U.S. patent application number 15/645752 was filed with the patent office on 2017-10-26 for vascular and bodily duct treatment devices and methods.
This patent application is currently assigned to CONCENTRIC MEDICAL, INC.. The applicant listed for this patent is CONCENTRIC MEDICAL, INC.. Invention is credited to Ryan M. Grandfield, Elliot H. Sanders, Scott D. Wilson.
Application Number | 20170303944 15/645752 |
Document ID | / |
Family ID | 46603332 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170303944 |
Kind Code |
A1 |
Grandfield; Ryan M. ; et
al. |
October 26, 2017 |
VASCULAR AND BODILY DUCT TREATMENT DEVICES AND METHODS
Abstract
Devices including, but not limited to, a self-expandable member
having a proximal end portion and a main body portion. The
self-expandable member is movable from a first delivery position to
a second placement position, in the first delivery position the
expandable member being in an unexpanded position and having a
nominal first diameter and in the second position the expandable
member being in a radially expanded position and having a second
nominal diameter greater than the first nominal diameter for
deployment within a vessel or duct of a patient. The expandable
member includes a plurality of cell structures with the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member and the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member.
Inventors: |
Grandfield; Ryan M.;
(Livermore, CA) ; Wilson; Scott D.; (Redwood City,
CA) ; Sanders; Elliot H.; (Hilo, HI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CONCENTRIC MEDICAL, INC. |
Fremont |
CA |
US |
|
|
Assignee: |
CONCENTRIC MEDICAL, INC.
Fremont
CA
|
Family ID: |
46603332 |
Appl. No.: |
15/645752 |
Filed: |
July 10, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14792367 |
Jul 6, 2015 |
9700331 |
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15645752 |
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13365884 |
Feb 3, 2012 |
9072537 |
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14792367 |
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13303890 |
Nov 23, 2011 |
8529596 |
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13365884 |
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13021364 |
Feb 4, 2011 |
8357179 |
|
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13303890 |
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12832857 |
Jul 8, 2010 |
8357178 |
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13021364 |
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12643942 |
Dec 21, 2009 |
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12832857 |
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12573676 |
Oct 5, 2009 |
8795345 |
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12643942 |
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12499713 |
Jul 8, 2009 |
8795317 |
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12573676 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/32075 20130101;
A61F 2/915 20130101; A61F 2230/0006 20130101; A61F 2002/018
20130101; A61B 2017/00778 20130101; A61B 17/320725 20130101; A61B
17/3207 20130101; A61B 17/221 20130101; A61B 2017/2215 20130101;
A61F 2230/0097 20130101; A61F 2002/016 20130101; A61F 2/01
20130101; A61F 2230/0069 20130101; A61F 2002/825 20130101; A61B
2017/22045 20130101 |
International
Class: |
A61B 17/221 20060101
A61B017/221; A61F 2/01 20060101 A61F002/01 |
Claims
1-20. (canceled)
21. An embolic obstruction retrieval device comprising: an elongate
self-expandable member having a radially expanded configuration and
a radially constrained configuration, the expandable member being
biased in the expanded configuration and comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements of the plurality being interconnected in a manner to form
a plurality of diagonally disposed cells defining a cell pattern,
the expandable member having a proximal portion, an elongate
central body portion, and a distal portion, wherein the cell
structures in the central body portion are circumferentially
disposed about a longitudinal axis of the expandable member, and
wherein a longitudinal slit free of undulating elements extends
lengthwise along the central body portion of the expandable
member.
22. The embolic obstruction retrieval device of claim 21, wherein
the slit extends along an entire length of the expandable
member.
23. The embolic obstruction retrieval device of claim 21, wherein
the slit extends diagonally, the slit defining a spiral free of
undulating elements around the longitudinal axis of the central
body portion.
24. The embolic obstruction retrieval device of claim 23, wherein
the slit extends diagonally along an entire length of the
expandable member.
25. The embolic obstruction retrieval device of claim 21, wherein a
first undulating element in the proximal portion comprises a first
substantially linear rail, and a second undulating element in the
proximal portion forms a second substantially linear rail, each of
the first and second substantially linear rails forming acute
angles with the longitudinal axis of the expandable member, and
wherein the slit originates at one of the first and second
substantially linear rails.
26. The embolic obstruction retrieval device of claim 21, wherein
the plurality of adjacent undulating elements are disposed and
interconnected in a manner so as to cause each cell of the
plurality to be diagonally disposed relative to another cell of the
plurality.
27. The embolic obstruction retrieval device of claim 21, further
comprising a proximally extending elongate wire coupled to a
proximal-most end of the proximal portion of the expandable
member.
28. The embolic obstruction retrieval device of claim 21, further
comprising a distally extending wire segment coupled to a
distal-most end of the distal portion of the expandable member.
29. The embolic obstruction retrieval device of claim 21, wherein
the cells in the central body portion of the expandable member are
symmetrically aligned with one another along a length of the
central body portion.
30. The embolic obstruction retrieval device of claim 21, wherein
the cells in the central body portion of the expandable member are
symmetrically unaligned with one another along a length of the
central body portion.
31. The embolic obstruction retrieval device of claim 21, wherein
at least a portion of the expandable member is coated with a
radiopaque material or otherwise comprises radiopaque markers.
32. An embolic obstruction retrieval device comprising: an elongate
self-expandable member having a radially expanded configuration and
a radially constrained configuration, the expandable member being
biased in the expanded configuration and comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements of the plurality being interconnected in a manner to form
a plurality of diagonally disposed cells defining a cell pattern,
the expandable member having a proximal portion, an elongate
central body portion, and a distal portion, wherein the cell
structures in the central body portion are circumferentially
disposed about a longitudinal axis of the expandable member,
wherein a longitudinal slit free of undulating elements extends
lengthwise and diagonally along the expandable member, the slit
defining a spiral free of undulating elements around the
longitudinal axis, and wherein a first undulating element in the
proximal portion comprises a first substantially linear rail, and a
second undulating element in the proximal portion forms a second
substantially linear rail, each of the first and second
substantially linear rails forming acute angles with the
longitudinal axis of the expandable member, and wherein the slit
originates at one of the first and second substantially linear
rails.
33. The embolic obstruction retrieval device of claim 32, wherein
the slit extends along an entire length of the expandable
member.
34. The embolic obstruction retrieval device of claim 32, wherein
the plurality of adjacent undulating elements are disposed and
interconnected in a manner so as to cause each cell of the
plurality to be diagonally disposed relative to another cell of the
plurality.
35. The embolic obstruction retrieval device of claim 32, wherein
at least a portion of the expandable member is coated with a
radiopaque material or otherwise comprises radiopaque markers.
Description
RELATED APPLICATION
[0001] This application claims the benefit to and is a continuation
of U.S. patent application Ser. No. 13/365,884, filed Feb. 3, 2012,
which is a continuation-in-part of U.S. patent application Ser. No.
13/303,890, filed Nov. 23, 2011, which is a continuation-in-part of
U.S. patent application Ser. No. 13/021,364, filed Feb. 4, 2011,
which is a continuation-in-part of U.S. patent application Ser. No.
12/832,857, filed Jul. 8, 2010, which is a a continuation-in-part
of U.S. patent application Ser. No. 12/643,942, filed Dec. 21,
2009, which is a continuation-in-part of U.S. patent application
Ser. No. 12/573,676, filed Oct. 5, 2009, which is a
continuation-in-part of U.S. patent application Ser. No.
12/499,713, filed Jul. 8, 2009, the disclosures of all of which
being incorporated herein by reference in their entireties as if
fully set forth here.
TECHNICAL FIELD
[0002] This application relates to devices and methods for treating
the vasculature and other ducts within the body.
BACKGROUND
[0003] Self-expanding prostheses, such as stents, covered stents,
vascular grafts, flow diverters, and the like have been developed
to treat ducts within the body. Many of the prostheses have been
developed to treat blockages within the vasculature and also
aneurysms that occur in the brain. What are needed are improved
treatment methods and devices for treating the vasculature and
other body ducts, such as, for example, aneurysms, stenoses,
embolic obstructions, and the like.
SUMMARY OF THE DISCLOSURE
[0004] In accordance with one implementation a vascular or bodily
duct treatment device is provided that comprises an elongate
self-expandable member movable from a first delivery position to a
second placement position, in the first delivery position the
expandable member being in an unexpanded position and having a
nominal first diameter and in the second position the expandable
member being in a radially expanded position and having a second
nominal diameter greater than the first nominal diameter for
deployment within the bodily duct or vasculature of a patient, the
expandable member comprising a plurality of cell structures, the
expandable member having a proximal end portion with a proximal
end, a cylindrical main body portion and a distal end portion with
a distal end, the cell structures in the main body portion
extending circumferentially around a longitudinal axis of the
expandable member, the cell structures in the proximal and distal
end portions extending less than circumferentially around the
longitudinal axis of the expandable member, the outer-most cell
structures in the proximal end portion having proximal-most linear
wall segments that, in a two-dimensional view, form first and
second substantially linear rail segments that each extend from a
position at or near the proximal-most end of the expandable member
to a distal position at or near the cylindrical main body portion.
In one implementation the self-expandable member has a longitudinal
slit extending along at least a portion of the length of the
self-expandable member between the proximal end and the distal
end.
[0005] In accordance with another implementation a kit is provided
that comprises an elongate flexible wire having a proximal end and
a distal end with an elongate self-expandable member coupled to the
distal end, the self-expandable member movable from a first
delivery position to a second placement position, in the first
delivery position the expandable member being in an unexpanded
position and having a nominal first diameter and in the second
position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment in the bodily duct or
vasculature of a patient, the self-expandable member comprising a
plurality of cell structures, the self-expandable member having a
proximal end portion with a proximal end, a cylindrical main body
portion and a distal end portion with a distal end, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal and distal end portions extending less
than circumferentially around the longitudinal axis of the
expandable member, the outer-most cell structures in the proximal
end portion having proximal-most linear wall segments that, in a
two-dimensional view, form first and second substantially linear
rail segments that each extend from a position at or near the
proximal-most end of the expandable member to a distal position at
or near the cylindrical main body portion, the elongate wire with
the expandable member having a first length; and a delivery
catheter having a second length and sufficient flexibility to
navigate the vasculature or bodily duct of the patient, the
delivery catheter having a proximal end, a distal end and an inner
lumen, the inner lumen having a diameter sufficient to receive the
self-expandable member in its unexpanded position and for advancing
the unexpanded member from the proximal end to the distal end of
the catheter, the second length being less than the first length to
allow distal advancement of the self-expandable member beyond the
distal end of the catheter to permit the expandable member to
deploy toward its expanded position, the distal end of the catheter
and the self-expandable member configured to permit proximal
retraction of the self-expandable member into the lumen of the
catheter when the self-expandable member is partially or fully
deployed outside the distal end of the catheter. In one
implementation, the self-expandable member has a longitudinal slit
extending along at least a portion of the length of the
self-expandable member between the proximal end and the distal
end.
[0006] In accordance with one implementation, a bodily duct or
vascular treatment device is provided having an elongate
self-expandable member movable from a first delivery position to a
second placement position, in the first delivery position the
expandable member being in an unexpanded position and having a
nominal first diameter and in the second position the expandable
member being in a radially expanded position and having a second
nominal diameter greater than the first nominal diameter for
deployment within the bodily duct or vasculature of a patient, the
expandable member comprising a plurality of generally longitudinal
undulating elements with adjacent undulating elements being
interconnected in a manner to form a plurality of diagonally
disposed cell structures, the expandable member having a proximal
end portion, a cylindrical main body portion and a distal end
portion, the cell structures in the main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal and distal end portions
extending less than circumferentially around the longitudinal axis
of the expandable member, the outer-most cell structures in the
proximal end portion having proximal-most linear wall segments
that, in a two-dimensional view, form first and second
substantially linear rail segments that each extend from a position
at or near the proximal-most end of the expandable member to a
position at or near the cylindrical main body portion. In one
implementation, connected to the proximal-most end of the
expandable member is a proximally extending elongate flexible wire
having a length and flexibility sufficient for navigating and
accessing the vasculature or bodily duct of the patient.
[0007] In accordance with another implementation, a vascular
treatment device is provided that includes an elongate
self-expandable member movable from a first delivery position to a
second placement position, in the first delivery position the
expandable member being in an unexpanded position and having a
nominal first diameter and in the second position the expandable
member being in a radially expanded position and having a second
nominal diameter greater than the first nominal diameter for
deployment within the vasculature of a patient, the expandable
member comprising a plurality of generally longitudinal undulating
elements with adjacent undulating elements being interconnected in
a manner to form a plurality of cell structures that are arranged
to induce twisting of the expandable member as the expandable
member transitions from the unexpanded position to the expanded
position, the expandable member having a proximal end portion, a
cylindrical main body portion and a distal end portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal and distal end portions extending less
than circumferentially around the longitudinal axis of the
expandable member, the outer-most cell structures in the proximal
end portion having proximal-most linear wall segments that form
first and second substantially linear rail segments that each
extend from a position at or near the proximal-most end of the
expandable member to a position at or near the cylindrical main
body portion. In one implementation, connected to the proximal-most
end of the expandable member is a proximally extending elongate
flexible wire having a length and flexibility sufficient for
navigating and accessing the vasculature or bodily duct of the
patient.
[0008] In accordance with another implementation, a bodily duct or
vascular treatment device is provided that includes an elongate
self-expandable member movable from a first delivery position to a
second placement position, in the first delivery position the
expandable member being in an unexpanded position and having a
nominal first diameter and in the second position the expandable
member being in a radially expanded position and having a second
nominal diameter greater than the first nominal diameter for
deployment within the bodily duct or vasculature of a patient, the
expandable member comprising a plurality of generally longitudinal
undulating elements with adjacent undulating elements being
interconnected to form a plurality of diagonally disposed cell
structures, the expandable member having a cylindrical portion and
a distal end portion, the cell structures in the cylindrical
portion extending circumferentially around a longitudinal axis of
the expandable member, the cell structures in the distal end
portion extending less than circumferentially around the
longitudinal axis of the expandable member, the proximal-most cell
structures in the main body portion having proximal-most end
points. One or more of the proximal-most end points of the
expandable member have a proximally extending elongate flexible
wire having a length and flexibility sufficient for navigating and
accessing the vasculature or bodily duct of the patient.
[0009] In accordance with another implementation, a kit is provided
that includes an elongate flexible wire having a proximal end and a
distal end with an elongate self-expandable member attached to the
distal end, the self-expandable member movable from a first
delivery position to a second placement position, in the first
delivery position the expandable member being in an unexpanded
position and having a nominal first diameter and in the second
position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within a bodily duct or
vasculature of a patient, the expandable member comprising a
plurality of generally longitudinal undulating elements with
adjacent undulating elements being interconnected in a manner to
form a plurality of diagonally disposed cell structures, the
expandable member having a proximal end portion, a cylindrical main
body portion and a distal end portion, the cell structures in the
main body portion extending circumferentially around a longitudinal
axis of the expandable member, the cell structures in the proximal
and distal end portions extending less than circumferentially
around the longitudinal axis of the expandable member, the
outer-most cell structures in the proximal end portion having
proximal-most linear wall segments that, in a two-dimensional view,
form first and second substantially linear rail segments that each
extend from a position at or near the proximal-most end of the
expandable member to a position at or near the cylindrical main
body portion, the elongate wire and expandable member having a
first length, and a delivery catheter having a second length and
sufficient flexibility to navigate the vasculature or bodily duct
of a patient, the delivery catheter having a proximal end, a distal
end and an inner diameter, the inner diameter sufficient to receive
the expandable member in its unexpanded position and for advancing
the unexpanded member from the proximal end to the distal end of
the catheter, the second length being less that the first length to
allow distal advancement of the expandable member beyond the distal
end of the catheter to permit the expandable member to deploy
toward its expanded position, the distal end of the catheter and
the expandable member configured to permit proximal retraction of
the expandable member into the catheter when the expandable member
is partially or fully deployed outside the distal end of the
catheter.
[0010] In accordance with another implementation, a method for
removing an embolic obstruction from a vessel of a patient is
provided that includes (a) advancing a delivery catheter having an
inner lumen with proximal end and a distal end to the site of an
embolic obstruction in the intracranial vasculature of a patient so
that the distal end of the inner lumen is positioned distal to the
embolic obstruction, the inner lumen having a first length, (b)
introducing an embolic obstruction retrieval device comprising an
elongate flexible wire having a proximal end and a distal end with
an elongate self-expandable member attached to the distal end into
the proximal end of the inner lumen of the catheter and advancing
the self-expandable member to the distal end of the lumen, the
self-expandable member movable from a first delivery position to a
second placement position, in the first delivery position the
expandable member being in an unexpanded position and having a
nominal first diameter and in the second position the expandable
member being in a radially expanded position and having a second
nominal diameter greater than the first nominal diameter for
deployment within an embolic obstruction of a patient, the
expandable member comprising a plurality of generally longitudinal
undulating elements with adjacent undulating elements being
interconnected in a manner to form a plurality of cell structures,
the expandable member having a proximal end portion, a cylindrical
main body portion and a distal end portion, the cell structures in
the main body portion extending circumferentially around a
longitudinal axis of the expandable member, the cell structures in
the proximal and distal end portions extending less than
circumferentially around the longitudinal axis of the expandable
member, the outer cell structures in the proximal end portion
having proximal linear wall segments that, in a two-dimensional
view, form first and second substantially linear rail segments that
each extend from a position at or near the proximal end of the
expandable member to a position at or near the cylindrical main
body portion, the elongate wire and expandable member in
combination having a second length longer than the first length,
(c) proximally retracting the delivery catheter sufficient to
deploy the self-expandable device so that the one or more of the
cell structures entrap at least a portion of the embolic
obstruction, and (d) proximally retracting the delivery catheter
and self-expandable device to outside the patient. In an
alternative implementation, the self-expandable member is partially
or fully retracted into the inner lumen of the delivery catheter
prior to proximally retracting the delivery catheter and
self-expandable device to outside the patient.
[0011] In accordance with another implementation, a device is
provided comprising an elongate self-expandable member movable from
a first delivery position to a second placement position, in the
first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within a vessel or duct of a
patient, the expandable member comprising a plurality of cell
structures, the expandable member having a proximal end portion
with a proximal end and a cylindrical main body portion, the cell
structures in the main body portion comprise a first plurality of
intersecting struts and extend circumferentially around a
longitudinal axis of the expandable member, the cell structures in
the proximal end portion comprise a second plurality of
intersecting struts and extend less than circumferentially around
the longitudinal axis of the expandable member, at least some of
the first plurality of intersecting struts having a thickness to
width ratio of greater than one.
[0012] In accordance with yet another implementation, a device is
provided comprising a delivery wire, an elongate self-expandable
member movable from a first delivery position to a second placement
position, in the first delivery position the expandable member
being in an unexpanded position and having a nominal first diameter
and in the second position the expandable member being in a
radially expanded position and having a second nominal diameter
greater than the first nominal diameter for deployment within a
vessel or duct of a patient, the expandable member comprising a
plurality of cell structures, the expandable member having a
proximal end portion with a proximal end and a cylindrical main
body portion, the proximal end having an integrally formed wire
segment extending therefrom with a coil positioned about the wire
segment, the coil comprising a first closely wound segment and a
second loosely wound segment that contains at least one gap, the
cell structures in the main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal end portion extending
less than circumferentially around the longitudinal axis of the
expandable member, a proximal end of the wire segment attached to a
distal end of the delivery wire by a bonding agent within the
second loosely wound segment of the coil.
[0013] In accordance with yet another implementation, a device is
provided comprising an elongate self-expandable member movable from
a first delivery position to a second placement position, in the
first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within a vessel or duct of a
patient, the expandable member comprising a plurality of cell
structures, the expandable member having a proximal end portion
with a proximal end and a cylindrical main body portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member, the cell structures having dimensional and material
characteristics that result in about a -1.5N to a about a -3.5N
overall reduction in radial force along the length of the
expandable member per millimeter of expansion during about an
initial 0.50 mm diametric range of expansion from the nominal
diameter and that results in about a -0.10N to about a -0.50N
overall reduction in radial force along the length of the
expandable member per millimeter of expansion during subsequent
diametric ranges of expansion. In one implementation the elongate
self-expandable member has a designated maximum second nominal
diameter, the radial force exerted by the elongate self-expandable
member being greater than zero when expanded to the maximum second
nominal diameter.
[0014] In accordance with yet another implementation, a device is
provided comprising an elongate self-expandable member movable from
a first delivery position to a second placement position, in the
first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within the bodily duct or
vasculature of a patient, the expandable member comprising a
plurality of generally longitudinal undulating elements with
adjacent undulating elements being interconnected in a manner to
form a plurality of diagonally disposed cell structures, the
expandable member having a proximal end portion, a cylindrical main
body portion and a distal end portion, the cell structures in the
main body portion extending circumferentially around a longitudinal
axis of the expandable member, the cell structures in the proximal
and distal end portions extending less than circumferentially
around the longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member, the cell structures having dimensional and material
characteristics that result in about a -1.5N to a about a -3.5N
overall reduction in radial force along the length of the
expandable member per millimeter of expansion during about an
initial 0.50 mm diametric range of expansion from the first nominal
diameter and that results in about a -0.10N to about a -0.50N
overall reduction in radial force along the length of the
expandable member per millimeter of expansion during subsequent
diametric ranges of expansion. In one implementation the elongate
self-expandable member has a designated maximum second nominal
diameter, the radial force exerted by the elongate self-expandable
member being greater than zero when expanded to the maximum second
nominal diameter.
[0015] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion and a cylindrical main body portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member to form first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth set of cell structures, the
proximal-most cell structure and the first set of cell structures
having circumferential outer-most strut members that define the
first peripheral rail, the proximal-most cell structure and the
second set of cell structures having circumferential outer-most
strut members that define the second peripheral rail, at least some
of the circumferential outer-most strut members having different
width dimensions and arranged so that the first and second
peripheral rails vary between a first width dimension at the
proximal end segment to second width dimension at the distal end
segment, the second width dimension less than the first width
dimension. In one implementation the first and second peripheral
rails are devoid of undulations and the percentage change between
the first width dimension and second width dimension is between
about 20.0% and about 50.0%.
[0016] In another implementations a clot retrieval devices is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion and a cylindrical main body portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member to form first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth set of cell structures, the
proximal-most cell structure and the first set of cell structures
having circumferential outer-most strut members that define the
first peripheral rail, the proximal-most cell structure and the
second set of cell structures having circumferential outer-most
strut members that define the second peripheral rail, at least some
of the circumferential outer-most strut members having different
width dimensions and arranged so that the first and second
peripheral rails vary between a first width dimension at the
proximal end segment to second width dimension at the distal end
segment, the second width dimension less than the first width
dimension, the percentage change between the first width dimension
and second width dimension is between about 20.0% and about 50.0%,
the third set of cell structures comprising struts having a third
width dimensions less than the second width dimension, the fourth
set of cell structures comprising struts having a fourth width
dimensions less than the second width dimension, the percentage
difference between the second width dimension and the third width
dimension being between about 10.0% and about 25.0%, the percentage
difference between the second width dimension and the fourth width
dimension being between about 10.0% and about 25.0%.
[0017] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion and a cylindrical main body portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member to form first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth set of cell structures, the
proximal-most cell structure and the first set of cell structures
having circumferential outer-most strut members that define the
first peripheral rail, the proximal-most cell structure and the
second set of cell structures having circumferential outer-most
strut members that define the second peripheral rail, at least some
of the circumferential outer-most strut members having different
width dimensions and arranged so that the first and second
peripheral rails vary between a first width dimension at the
proximal end segment to second width dimension at the distal end
segment, the second width dimension less than the first width
dimension, the percentage change between the first width dimension
and second width dimension is between about 20.0% and about 50.0%,
the third set of cell structures comprising struts having a third
width dimension less than the second width dimension, the fourth
set of cell structures comprising struts having a fourth width
dimension substantially the same as the second width dimension, the
percentage difference between the second width dimension and the
third width dimension being between about 10.0% and about
25.0%.
[0018] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion and a cylindrical main body portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member to form first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth and fifth set of cell
structures, the proximal-most cell structure and the first set of
cell structures having circumferential outer-most strut members
that define the first peripheral rail, the proximal-most cell
structure and the second set of cell structures having
circumferential outer-most strut members that define the second
peripheral rail, at least some of the circumferential outer-most
strut members having different width dimensions and arranged so
that the first and second peripheral rails vary between a first
width dimension at the proximal end segment to second width
dimension at the distal end segment, the second width dimension
less than the first width dimension, the size of the cell
structures in the third and fifth set of cell structures being
substantially the same, the size of the cell structures in the
fourth set of cell structures being greater than the size of the
cell structures in the third set of cell structures, the cell
structures in the third, fourth and fifth set of cell structures
comprising third, fourth and fifth struts, respectively, at least
some of the fourth and fifth struts, or segments thereof, having a
width dimension that is greater than the width dimension of the
third struts.
[0019] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion and a cylindrical main body portion, the cell
structures in the main body portion extending circumferentially
around a longitudinal axis of the expandable member, the cell
structures in the proximal end portion extending less than
circumferentially around the longitudinal axis of the expandable
member to form first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth and fifth set of cell
structures, the proximal-most cell structure and the first set of
cell structures having circumferential outer-most strut members
that define the first peripheral rail, the proximal-most cell
structure and the second set of cell structures having
circumferential outer-most strut members that define the second
peripheral rail, at least some of the circumferential outer-most
strut members having different width dimensions and arranged so
that the first and second peripheral rails vary between a first
width dimension at the proximal end segment to second width
dimension at the distal end segment, the second width dimension
less than the first width dimension, the size of the cell
structures in the third and fifth set of cell structures being
substantially the same, the size of the cell structures in the
fourth set of cell structures being greater than the size of the
cell structures in the third set of cell structures, the cell
structures in the third, fourth and fifth set of cell structures
comprising third, fourth and fifth struts, respectively, the width
dimension of the third struts being less than the second width
dimension, at least some of the fourth and fifth struts, or
segments thereof, having a width dimension substantially equal to
the second width dimension.
[0020] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion, a cylindrical main body portion and a distal
end portion, the cell structures in the main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal and distal end portions
extending less than circumferentially around the longitudinal axis
of the expandable member, the cell structures in the proximal end
portion forming first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth set of cell structures, the
cell structures in the distal end portion comprising a sixth set of
cell structures, the proximal-most cell structure and the first set
of cell structures having circumferential outer-most strut members
that define the first peripheral rail, the proximal-most cell
structure and the second set of cell structures having
circumferential outer-most strut members that define the second
peripheral rail, at least some of the circumferential outer-most
strut members having different width dimensions and arranged so
that the first and second peripheral rails vary between a first
width dimension at the proximal end segment to second width
dimension at the distal end segment, the second width dimension
less than the first width dimension. In one implementation the
first and second peripheral rails are devoid of undulations and the
percentage change between the first width dimension and second
width dimension is between about 20.0% and about 50.0%.
[0021] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion, a cylindrical main body portion and a distal
end portion, the cell structures in the main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal and distal end portions
extending less than circumferentially around the longitudinal axis
of the expandable member, the cell structures in the proximal end
portion forming first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth and fifth set of cell
structures, the cell structures in the distal end portion
comprising a sixth set of cell structures, the proximal-most cell
structure and the first set of cell structures having
circumferential outer-most strut members that define the first
peripheral rail, the proximal-most cell structure and the second
set of cell structures having circumferential outer-most strut
members that define the second peripheral rail, at least some of
the circumferential outer-most strut members having different width
dimensions and arranged so that the first and second peripheral
rails vary between a first width dimension at the proximal end
segment to second width dimension at the distal end segment, the
second width dimension less than the first width dimension, the
size of the cell structures in the third, fifth and sixth set of
cell structures being substantially the same, the size of the cell
structures in the fourth set of cell structures being greater than
the size of the cell structures in the third, fifth and sixth set
of cell structures, the cell structures in the third, fourth, fifth
and sixth set of cell structures comprising third, fourth, fifth
and sixth struts, respectively, at least some of the fourth and
fifth struts, or segments thereof, having a width dimension that is
greater than the width dimension of the third and sixth struts.
[0022] In another implementation a clot retrieval device is
provided comprising: an elongate self-expandable member movable
from a first delivery position to a second placement position, in
the first delivery position the expandable member being in an
unexpanded position and having a nominal first diameter and in the
second position the expandable member being in a radially expanded
position and having a second nominal diameter greater than the
first nominal diameter for deployment within an embolic obstruction
of a patient, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal end portion, a cylindrical main body portion and a distal
end portion, the cell structures in the main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal and distal end portions
extending less than circumferentially around the longitudinal axis
of the expandable member, the cell structures in the proximal end
portion forming first and second peripheral rails having proximal
and distal end segments, the cell structures in the proximal end
portion comprising a first set of cell structures arranged to form
the first peripheral rail, a second set of cell structures arranged
to form the second peripheral rail and a third set of cell
structures located between the first and second set of cell
structures, the first and second set of cell structures having in
common a proximal-most cell structure, the cell structures in the
main body portion comprising a fourth and fifth set of cell
structures, the cell structures in the distal end portion
comprising a sixth set of cell structures, the proximal-most cell
structure and the first set of cell structures having
circumferential outer-most strut members that define the first
peripheral rail, the proximal-most cell structure and the second
set of cell structures having circumferential outer-most strut
members that define the second peripheral rail, at least some of
the circumferential outer-most strut members having different width
dimensions and arranged so that the first and second peripheral
rails vary between a first width dimension at the proximal end
segment to second width dimension at the distal end segment, the
second width dimension less than the first width dimension, the
size of the cell structures in the third, fifth and sixth set of
cell structures being substantially the same, the size of the cell
structures in the fourth set of cell structures being greater than
the size of the cell structures in the third, fifth and sixth set
of cell structures, the cell structures in the third, fourth, fifth
and sixth set of cell structures comprising third, fourth, fifth
and sixth struts, respectively, the width dimension of the third
and sixth struts being less than the second width dimension, at
least some of the fourth and fifth struts, or segments thereof,
having a width dimension substantially equal to the second width
dimension.
[0023] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
movable from a first delivery position to a second placement
position, in the first delivery position the expandable member
being in an unexpanded position and having a nominal first diameter
and in the second position the expandable member being in a
radially expanded position and having a second nominal diameter
greater than the first nominal diameter for deployment within an
embolic obstruction of a patient, the expandable member comprising
a plurality of generally longitudinal undulating elements with
adjacent undulating elements being interconnected in a manner to
form a plurality of diagonally disposed cell structures, the
expandable member having a proximal antenna, a proximal end portion
and a cylindrical main body portion, the cell structures in the
main body portion extending circumferentially around a longitudinal
axis of the expandable member, the cell structures in the proximal
and distal end portions extending less than circumferentially
around the longitudinal axis of the expandable member, the
outer-most cell structures in the proximal end portion having
proximal-most wall segments that form first and second rail
segments that each extend from a position at or near the
proximal-most end of the expandable member to a position at or near
the cylindrical main body portion, the proximal-most cell structure
of the proximal end portion comprising first and second outer
struts that extend distally from the proximal antenna, in a
two-dimensional layout at least a portion of each of the first and
second outer struts comprise a straight segment, each of the
straight segment being coextensive to the proximal antenna.
[0024] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
movable from a first delivery position to a second placement
position, in the first delivery position the expandable member
being in an unexpanded position and having a nominal first diameter
and in the second position the expandable member being in a
radially expanded position and having a second nominal diameter
greater than the first nominal diameter for deployment within an
embolic obstruction of a patient, the expandable member comprising
a plurality of generally longitudinal undulating elements with
adjacent undulating elements being interconnected in a manner to
form a plurality of diagonally disposed cell structures, the
expandable member having a proximal antenna, a proximal end portion
and a cylindrical main body portion, the cell structures in the
main body portion extending circumferentially around a longitudinal
axis of the expandable member, the cell structures in the proximal
and distal end portions extending less than circumferentially
around the longitudinal axis of the expandable member, a first set
of outer-most cell structures in the proximal end portion having
proximal-most wall segments that form a non-undulating rail segment
that extends from a position at or near the proximal-most end of
the expandable member to a position at or near the cylindrical main
body portion, and a second set of outer-most cell structures in the
proximal end portion having proximal-most wall segments that form
an undulating rail segment that extends from a position at or near
the proximal-most end of the expandable member to a position at or
near the cylindrical main body portion.
[0025] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
having a radially expanded configuration and a radially unexpanded
configuration, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal antenna, a proximal end portion and a cylindrical main
body portion comprising a proximal section and a distal section,
the cell structures in the cylindrical main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal end portion extending
less than circumferentially around the longitudinal axis of the
expandable member, in the expanded configuration the distal section
of the cylindrical main body portion having an average diameter
greater than the average diameter of the proximal section of the
cylindrical main body portion. In some implementations the average
length of the cell structures in the distal section of the
cylindrical main body portion is greater than the average length of
the cell structures in the proximal section of the cylindrical main
body portion, the average length of the cell structures in the
proximal section of the cylindrical main body portion being greater
than the average length of the cell structures in the proximal end
portion, the average length to width ratio of the cell structures
in the proximal end portion and cylindrical main body portion being
greater than one when the self-expandable member is in the
constrained and unconstrained configuration.
[0026] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
having a radially expanded configuration and a radially unexpanded
configuration, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal antenna, a proximal end portion and a cylindrical main
body portion comprising a proximal section and a distal section,
the cell structures in the cylindrical main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal end portion extending
less than circumferentially around the longitudinal axis of the
expandable member, the average length to width ratio of the cell
structures in the distal section of the cylindrical main body
portion being greater than the average length to width ratio of the
cell structures in the proximal section of the cylindrical main
body portion, the average length to width ratio of the cell
structures in the proximal section of the cylindrical main body
portion being greater than the average length to width ratio of the
cell structures in the proximal end portion, the average length to
width ratio of the cell structures in the proximal end portion
being greater than one when the self-expandable member is in the
unexpanded and expanded configuration.
[0027] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
having a radially expanded configuration and a radially unexpanded
configuration, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal antenna, a proximal end portion and a cylindrical main
body portion, the cell structures in the cylindrical main body
portion extending circumferentially around a longitudinal axis of
the expandable member, the cell structures in the proximal end
portion extending less than circumferentially around the
longitudinal axis of the expandable member, the cell structures in
the cylindrical main body portion comprising proximal and distal
facing V-like structures that are interconnected by a pair of
diagonally extending and circumferentially spaced-apart struts, the
proximal and distal V-like structures having a first average width
dimension and the pair of diagonally extending and
circumferentially spaced-apart struts having a second average width
dimension that is greater than the first average width
dimension.
[0028] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
having a radially expanded configuration and a radially unexpanded
configuration, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal antenna, a proximal end portion and a cylindrical main
body portion comprising a proximal section and a distal section,
the cell structures in the cylindrical main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal end portion extending
less than circumferentially around the longitudinal axis of the
expandable member, the cell structures in the cylindrical main body
portion comprising proximal and distal facing V-like structures
that are interconnected by a pair of diagonally extending and
circumferentially spaced-apart struts, the diagonally extending and
circumferentially spaced-apart struts comprising first end
segments, second end segments, and a middle segment disposed
between the first and second end segments, the first end segments
being coupled to the proximal V-like structure and the second end
segments being coupled to the distal V-like structure, the proximal
and distal V-like structures having a first average width
dimension, the middle segments of the diagonally extending and
circumferentially spaced-apart struts having a second average width
dimension that is greater than the first average width dimension,
the first and second end segments of the diagonally extending and
circumferentially spaced-apart struts having a third average width
dimension that is greater than the first average width dimension
and less than the second average width dimension.
[0029] In other implementations embolic obstruction retrieval
devices are provided comprising; an elongate self-expandable member
having a radially expanded configuration and a radially unexpanded
configuration, the expandable member comprising a plurality of
generally longitudinal undulating elements with adjacent undulating
elements being interconnected in a manner to form a plurality of
diagonally disposed cell structures, the expandable member having a
proximal antenna, a proximal end portion and a cylindrical main
body portion comprising a proximal section and a distal section,
the cell structures in the cylindrical main body portion extending
circumferentially around a longitudinal axis of the expandable
member, the cell structures in the proximal end portion extending
less than circumferentially around the longitudinal axis of the
expandable member, the cell structures in the cylindrical main body
portion comprising proximal and distal V-like structures that are
interconnected by a pair of diagonally extending and
circumferentially spaced-apart struts, at least some of the
diagonally extending and circumferentially spaced-apart struts
having one or more wires or ribbons wound thereabout so as to
enhance the average deflection stiffness of all or a portion of the
cylindrical main body portion when the self-expandable member is in
the radially expanded configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Alternative implementations of the present disclosure are
described herein with reference to the drawings wherein:
[0031] FIG. 1A illustrates a two-dimensional plane view of an
expandable member of a treatment device in one embodiment.
[0032] FIG. 1B is an isometric view of the expandable member
illustrated in FIG. 1A
[0033] FIG. 2 illustrates a distal wire segment that extends
distally from an expandable member in one embodiment.
[0034] FIG. 3 illustrates the distal end of an expandable member
having an atraumatic tip.
[0035] FIG. 4A illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0036] FIG. 4B is an enlarged view of the proximal-most segment of
the expandable member illustrated in FIG. 4A.
[0037] FIG. 5 illustrates a distal end of an expandable member in
one embodiment.
[0038] FIG. 6A illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0039] FIG. 6B is an isometric view of the expandable member
illustrated in FIG. 6A.
[0040] FIG. 7A illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0041] FIG. 7B is an isometric view of the expandable member
illustrated in FIG. 7A.
[0042] FIG. 7C illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0043] FIG. 8 illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0044] FIG. 9 illustrates an expandable member in an expanded
position having a bulge or increased diameter portion.
[0045] FIG. 10 illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0046] FIG. 11A illustrates a two-dimensional plane view of an
expandable member of a treatment device in one implementation.
[0047] FIG. 11B is an isometric view of the expandable member
illustrated in FIG. 11A.
[0048] FIG. 12 illustrates a two-dimensional plane view of an
expandable member of a treatment device in another
implementation.
[0049] FIGS. 13A through 13C illustrate a method for retrieving an
embolic obstruction in accordance with one implementation.
[0050] FIG. 14 illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0051] FIG. 15 illustrates a two-dimensional plane view of an
expandable member of a treatment device in yet another
embodiment.
[0052] FIG. 16 illustrates an isometric view of an expandable
member in another embodiment having an internal wire segment.
[0053] FIG. 17 illustrates an isometric view of an expandable
member in another embodiment having an external wire segment.
[0054] FIG. 18 illustrates an isometric view of an expandable
member in yet another embodiment having a distal emboli capture
device.
[0055] FIG. 19 illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0056] FIG. 20 illustrates the expandable member of FIG. 19 having
a longitudinal slit.
[0057] FIG. 21 illustrates the expandable member of FIG. 19 having
a spiral slit.
[0058] FIG. 22 illustrates the expandable member of FIG. 19 having
a partial spiral slit.
[0059] FIG. 23 illustrates a two-dimensional plane view of an
expandable member of a treatment device in another embodiment.
[0060] FIG. 24A illustrates a two-dimensional plane view of an
expandable member of a treatment device in yet another
embodiment.
[0061] FIG. 24B is an isometric view of the expandable member
illustrated in FIG. 24A.
[0062] FIG. 25 illustrates a manner in which the proximal extending
wire segment of an expandable device is attached to a delivery wire
in one embodiment.
[0063] FIG. 26 illustrates a two-dimensional plane view of an
expandable member of a treatment device in yet another
embodiment.
[0064] FIGS. 27A and 27B illustrate isometric side and top views,
respectively, of the expandable member depicted in FIG. 26.
[0065] FIGS. 28A and 28B illustrate a proximal wire segment and a
distal wire segment, respectively, of an expandable member in one
implementation.
[0066] FIG. 29 is a graph representing a radial force curve of an
expandable member according to one implementation.
[0067] FIG. 30 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0068] FIG. 31 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0069] FIGS. 32A-C illustrate cell structures according to some of
the implementations of FIG. 31.
[0070] FIG. 33A illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0071] FIGS. 33B and 33C illustrate top and side isometric views of
the device illustrated in FIG. 33A.
[0072] FIG. 34A illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0073] FIGS. 34B and 34C illustrate top and side isometric views of
the device illustrated in FIG. 34A.
[0074] FIG. 35A illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0075] FIGS. 35B and 35C illustrate top and side isometric views of
the device illustrated in FIG. 35A.
[0076] FIG. 36 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0077] FIG. 37 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0078] FIG. 38 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0079] FIG. 39 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0080] FIG. 40A illustrates a two-dimensional plane view of a clot
retrieval device according to one implementation.
[0081] FIG. 40B illustrates a three-dimensional view of the clot
retrieval device of FIG. 40A.
[0082] FIG. 41 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0083] FIG. 42A illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0084] FIG. 42B illustrates an enlarged two-dimensional plane view
of the proximal tapered end portion of the retriever device
depicted in FIG. 45A.
[0085] FIG. 43 illustrates a two-dimensional plane view of a
proximal-most cell structure according some implementations.
[0086] FIG. 44 illustrates a two-dimensional plane view of a
proximal-most cell structure according some implementations.
[0087] FIGS. 45A-C illustrate two-dimensional plane views of clot
retrieval devices according some implementations.
[0088] FIG. 46 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0089] FIG. 47A illustrates a two-dimensional plane view of a
distal end of clot retrieval devices according some
implementations.
[0090] FIG. 47B illustrates a three-dimensional view of the distal
end depicted in FIG. 47A.
[0091] FIG. 48A illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0092] FIG. 48B illustrates a three-dimensional view of the clot
retrieval device depicted in FIG. 48A.
[0093] FIG. 49 illustrates a two-dimensional plane view of clot
retrieval devices according some implementations.
[0094] FIG. 50 illustrates a two-dimensional plane view of distal
segment of a retrieval device according some implementations.
[0095] FIGS. 51A-D illustrate two-dimensional plane views of
retrieval devices according to some implementations.
[0096] FIGS. 52A and 52B illustrate two-dimensional plane views of
retrieval devices according to some implementations.
[0097] FIG. 53 illustrates a two-dimensional plane view of a
retrieval device according to some implementations.
[0098] FIG. 54 illustrates a two-dimensional plane view of a
retrieval device according to some implementations.
[0099] FIG. 55 illustrates a two-dimensional plane view of a
retrieval device according to some implementations.
[0100] FIGS. 56A and 56B illustrates a two-dimensional plane view
of retrieval devices according to some implementations.
[0101] FIG. 57 illustrates a two-dimensional plane view of a
retrieval device according to some implementations.
[0102] FIG. 58A illustrates a two-dimensional plane view of a
retrieval device according to some implementations.
[0103] FIG. 58B illustrates an enlarged view of cell structures
depicted in FIG. 58A.
[0104] FIG. 59A illustrates a side view of a joint member according
to one implementation.
[0105] FIG. 59B illustrates a cross-sectional view of the joint
member depicted in FIG. 59A.
[0106] FIGS. 60A and 60B show wire attachment configurations
according to some implementations.
DETAILED DESCRIPTION
[0107] FIGS. 1A and 1B illustrate a vascular or bodily duct
treatment device 10 in accordance with one embodiment of the
present invention. Device 10 is particularly suited for accessing
and treating the intracranial vascular of a patient, such as for
example treating aneurysms or capturing and removing embolic
obstructions. It is appreciated however, that device 10 may be used
for accessing and treating other locations within the vasculature
and also other bodily ducts. Other uses include, for example,
treating stenoses and other types of vascular diseases and
abnormalities. FIG. 1A depicts device 10 in a two-dimensional plane
view as if the device were cut and laid flat on a surface. FIG. 1B
depicts the device in its manufactured and/or expanded tubular
configuration. Device 10 includes a self-expandable member 12 that
is attached or otherwise coupled to an elongate flexible wire 40
that extends proximally from the expandable member 12. In one
embodiment, the expandable member 12 is made of shape memory
material, such as Nitinol, and is preferably laser cut from a tube.
In one embodiment, the expandable member 12 has an integrally
formed proximally extending wire segment 42 that is used to join
the elongate flexible wire 40 to the expandable member 12. In such
an embodiment, flexible wire 40 may be joined to wire segment 42 by
the use of solder, a weld, an adhesive, or other known attachment
method. In an alternative embodiment, the distal end of flexible
wire 40 is attached directly to a proximal end 20 of the expandable
member 12. In one embodiment, the distal end of wire 40 has a flat
profile with a width of about 0.005 inches with the width and
thickness of the wire segment 42 being about 0.0063 and about
0.0035 inches, respectively.
[0108] In one embodiment, the distal end of wire 40 is attached to
the proximally extending wire segment 42 by the following method,
resulting in the joint illustrated in FIG. 25. In one
implementation, a coil 41 is positioned over wire segment 42, the
coil having a closely wrapped segment 41a abutting the proximal end
of expandable member 12, and a loosely wrapped segment 41b that
includes one or more gaps 41c. The size of the one or more gaps 41c
being sufficient to introduce a bonding agent into at least the
inner cavity of coil segment 41b. In one embodiment, the length of
wire segment 42 and the coil 41 are equal. In one embodiment the
length of the wire segment 42 is 4.0 millimeters with the coil 41
being of equal length. Once the coil 41 has been placed over the
wire segment 42, the distal end of wire 40 is placed within coil
segment 41b so that it makes contact with and overlaps the proximal
end portion of wire segment 42. A bonding agent is then applied
through the gaps 41c of coil 41 to bond the wire 40 with wire
segment 41. The bonding agent may be an adhesive, solder, or any
other suitable bonding agent. When the bonding agent is a solder, a
preceding step in the process involves coating the distal end
portion of wire 40 and the proximal end portion of wire segment 42
with tin or another suitable wetting agent. In one implementation
the solder is gold and is used to enhance the radiopacity of the
joint so that the joint may serve as a proximal radiopaque marker.
In addition to the use of gold, all or portions of the coil may be
made of a radiopaque material to further enhance the radiopacity of
the joint. According to one embodiment, the length of overlap
between the wire 40 and wire segment 42 is between 0.75 and 1.0
millimeters. In the same implementation or in other
implementations, the length of coil segment 41b is equal, or
substantially equal, to the overlap length of the wire 40 and wire
segment 42. In an alternative embodiment, in lieu of the use of a
single coil 41, two or more coils in abutting relationship are used
with, for example, a first closely wound coil abutting the proximal
end 20 of the expandable member 12 and a second loosely wound coil
with gaps situated proximal to the closely wound coil. Although not
shown in the figures, in one embodiment a distal end length of wire
40 is tapers in the distal direction from a nominal diameter to a
reduced profile. Along this length is provided a distal wire coil
of a constant outer diameter with no taper. In accordance with one
implementation, the diameter of coil 41 has the same outer diameter
as the distal wire coil.
[0109] One advantage of the joint construction is that it is
resistant to buckling while the device is being pushed through a
delivery catheter while at the same time being sufficiently
flexible to enable the device to be delivered through the tortuous
anatomy of a patient. In addition, the joint is able to withstand
high tensile and torque loads without breaking. Load test have
shown the joint of the previously described embodiment can
withstand in excess of 2 pounds of tensile stress. In one
embodiment, coil 41 is made of a radiopaque material to also
function as a proximal radiopaque marker.
[0110] FIG. 28A depicts an alternative proximal wire segment
construction. As shown, the proximal wire segment 4002 comprises a
first section 4002a and a second section 4002b, with the second
section 4002b having a width W greater than the width of the first
section. In one implementation a tapered transition section 4003
joins the first and second sections 4002a and 4002b. In one
implementation the width of the first section 4002a is about 0.0063
inches while the width W of the second section is between about
0.0085 inches and about 0.0105 inches. In one implementation the
length L between the proximal end 4005 of the expandable member
4004 and second section 4002b of the wire segment 4002 is between
about 0.017 inches and about 0.022 inches. An advantage of the
inclusion of the second section 4002b is that the greater width
dimension provides a larger surface area for bonding the wire
segment 4002 to the elongate wire 40 used in the delivery and
retraction of the elongate member from a duct of a patient. In one
implementation the first section 4002a has a circular or
substantially circular construction and the second section 4002b
has a flat profile formed by a pressing/coining operation.
[0111] In the embodiment of FIGS. 1A and 1B, expandable member 12
includes a plurality of generally longitudinal undulating elements
24 with adjacent undulating elements being out-of-phase with one
another and connected in a manner to form a plurality of diagonally
disposed cell structures 26. The expandable member 12 includes a
proximal end portion 14, a cylindrical main body portion 16 and a
distal end portion 18 with the cell structures 26 in the main body
portion 16 extending continuously and circumferentially around a
longitudinal axis 30 of the expandable member 12. The cell
structures 26 in the proximal end portion 14 and distal end portion
18 extend less than circumferentially around the longitudinal axis
30 of the expandable member 12.
[0112] In one embodiment, expandable member 12 has an overall
length of about 33.0 millimeters with the main body portion 16
measuring about 16.0 millimeters in length and the proximal and
distal end portions 14 and 18 each measuring about 7.0 millimeters
in length. In alternative embodiments, the length of the main body
portion 16 is generally between about 2.5 to about 3.5 times
greater than the length of the proximal and distal end portions 14
and 18.
[0113] In use, expandable member 12 is advanced through the
tortuous vascular anatomy or bodily duct of a patient to a
treatment site in an unexpanded or compressed state (not shown) of
a first nominal diameter and is movable from the unexpanded state
to a radially expanded state of a second nominal diameter greater
than the first nominal diameter for deployment at the treatment
site. In alternative exemplary embodiments the first nominal
diameter (e.g., average diameter of main body portion 16) ranges
between about 0.017 to about 0.030 inches, whereas the second
nominal diameter (e.g., average diameter of main body portion 16)
is between about 2.5 to about 5.0 millimeters. In one
implementation, the dimensional and material characteristics of the
cell structures 26 residing in the main body portion 16 of the
expandable material 12 are selected to produce sufficient radial
force and contact interaction to cause the cell structures 26 to
engage with an embolic obstruction residing in the vascular in a
manner that permits partial or full removal of the embolic
obstruction from the patient. In alternative embodiments the
dimensional and material characteristics of the cell structures 26
in the main body portion 16 are selected to produce a radial force
per unit length of between about 0.005 N/mm to about 0.050 N/mm,
preferable between about 0.010 N/mm to about 0.050 N/mm, and more
preferably between about 0.030 N/mm and about 0.050 N/mm. In one
embodiment, the diameter of the main body portion 16 in a fully
expanded state is about 4.0 millimeters with the cell pattern,
strut dimensions and material being selected to produce a radial
force of between about 0.040 N/mm to about 0.050 N/mm when the
diameter of the main body portion is reduced to between about 1.0
millimeters to about 1.5 millimeters. In the same or alternative
embodiment, the cell pattern, strut dimensions and material(s) are
selected to produce a radial force of between about 0.010 N/mm to
about 0.020 N/mm when the diameter of the main body portion is
reduced to 3.0 millimeters.
[0114] In the embodiments of FIGS. 1A and 1B, each of the cell
structures 26 are shown having the same dimensions with each cell
structure including a pair of short struts 32 and a pair of long
struts 34. In an exemplary embodiment, struts 32 have a length of
between about 0.080 and about 0.100 inches, struts 34 have a length
of between about 0.130 and about 0.140 inches, with each of struts
32 and 34 having an as-cut width and thickness of about 0.003
inches and about 0.0045 inches, respectively, and a post-polishing
width and thickness of between about 0.0022 inches and about 0.0039
inches, respectively. An advantage of having a strut thickness to
width ratio of greater than one is that it promotes integration of
the strut into the embolic obstruction. In alternative embodiments,
the post-polishing width and thickness dimensions varies between
about 0.0020 inches to about 0.0035 and about 0.0030 inches to
about 0.0040 inches, respectively, with the thickness to width
ratio varying between about 1.0 to about 2.0, and preferably
between about 1.25 to about 1.75.
[0115] In one embodiment, only the strut elements of the main body
portion 16 have a thickness to width dimension ratio of greater
than one. In another embodiment, only the strut elements of the
main body portion 16 and distal end portion 18 have a thickness to
width dimension ratio of greater than one. In another embodiment,
only a portion of the strut elements have a thickness to width
dimension ratio of greater than one. In yet another embodiment,
strut elements in different parts of the expandable member have
different thickness to width dimension ratios, the ratios in each
of the parts being greater than one. As an example, because the
radial force exerted by the proximal end portion 14 and distal end
portion 18 of the expandable member 12 may generally be less than
the radial force exerted by the main body portion 16, the strut
elements in the distal and/or proximal end portions can have a
thickness to width ratio that is greater than the thickness to
width ratio of the struts in the main body portion 16. An advantage
of this construction is that the ability of the expandable member
12 to integrate into an embolic obstruction is made to be more
uniform along the length of the expandable member.
[0116] In other embodiments, certain, or all of the strut elements
have a tapered shape with the outer face of the strut having a
width dimension less than the width dimension of the inner face of
the strut. In other embodiments, the expandable member 12 may
comprise strut elements having a generally rectangular
cross-section and also strut elements having a tapered shape.
[0117] It is important to note that the present invention is not
limited to expandable members 12 having uniform cell structures nor
to any particular dimensional characteristics. As an example, in
alternative embodiments the cell structures 26 in the proximal
and/or distal end portions 14 and 18 are either larger or smaller
in size than the cell structures 26 in the main body portion 16. In
one embodiment, the cell structures 26 in the proximal and distal
end portions 14 and 18 are sized larger than those in the main body
portion 16 so that the radial forces exerted in the end portions 14
and 18 are lower than the radial forces exerted in the main body
portion 16.
[0118] The radial strength along the length of the expandable
member 12 may be varied in a variety of ways. One method is to vary
the mass (e.g., width and/or thickness) of the struts along the
length of the expandable member 12. Another method is to vary the
size of the cell structures 26 along the length of the expandable
member 12. The use of smaller cell structures will generally
provide higher radial forces than those that are larger. Varying
the radial force exerted along the length of the expandable member
can be particularly advantageous for use in entrapping and
retrieving embolic obstructions. For example, in one embodiment the
radial force in the distal section of the main body portion 16 of
the expandable member 12 in its expanded state is made to be
greater than the radial force in the proximal section of the main
body portion 16. Such a configuration promotes a larger radial
expansion of the distal section of the main body portion 16 into
the embolic obstruction as compared to the proximal section.
Because the expandable member 12 is pulled proximally during the
removal of the embolic obstruction from the patient, the
aforementioned configuration will reduce the likelihood of
particles dislodging from the embolic obstruction during its
removal. In an alternative embodiment the radial force in the
proximal section of the main body portion 16 of the expandable
member 12 in its expanded state is made to be greater than the
radial force in the distal section of the main body portion 16. In
yet another embodiment, the main body portion 16 of the expandable
member 12 includes a proximal section, a midsection and a distal
section with the radial force in the proximal and distal sections
being larger than the radial force in the midsection when the
expandable member 12 is in an expanded state.
[0119] In alternative embodiments, as exemplified in FIG. 9, the
main body portion 16 may include an increased diameter portion or
bulge 70 to enhance the expandable member's ability to entrap or
otherwise engage with an embolic obstruction. In FIG. 9, a single
increased diameter portion 70 is provided within the midsection of
main body portion 16. In alternative embodiments, the increased
diameter portion 70 may be positioned proximally or distally to the
midsection. In yet other embodiments, two or more increased
diameter portions 70 may be provided along the length of the main
body portion 16. In one implementation, the two or more increased
diameter portions 70 have essentially the same manufactured nominal
diameter. In another implementation, the distal-most increased
diameter portion 70 has a greater manufactured nominal diameter
than the proximally disposed increased diameter portions. In
alternative exemplary embodiments the nominal diameter of the
increased diameter portion 70 is between about 25.0 to about 45.0
percent greater than the nominal diameter of the main body portion.
For example, in one embodiment, the nominal expanded diameter of
main body portion 16 is about 3.0 millimeters and the nominal
diameter of the increased diameter portion 70 is about 4.0
millimeters. In another embodiment the nominal expanded diameter of
main body portion 16 is about 3.50 millimeters and the nominal
diameter of the increased diameter portion 70 is about 5.00
millimeters. In one embodiment, the one or more increased diameter
portions 70 are formed by placing an expandable mandrel into the
internal lumen of the main body portion 16 and expanding the
mandrel to create the increased diameter portion 70 of a desired
diameter. In another embodiment, one or more of the increased
diameter portions 70 are formed by placing a mandrel of a given
width and diameter into the main body portion 16 and then crimping
the expandable member 12 in a manner to cause at least a portion of
the main body portion 16 to be urged against the mandrel.
[0120] In one embodiment, the strut elements in the increased
diameter portion or portions 70 have a thickness dimension to width
dimension ratio that is greater than the thickness to width ratio
of the other struts in the main body portion 16. In yet another
embodiment, the strut elements in the increased diameter portion or
portions 70 have a thickness dimension to width dimension ratio
that is less than the thickness to width ratio of the other struts
in the main body portion 16.
[0121] In one implementation, a distal wire segment 50, that is
attached to or integrally formed with expandable member 12, extends
distally from the distal end 22 of the expandable member 12 and is
configured to assist in guiding the delivery of the expandable
member to the treatment site of a patient. FIG. 2 shows a distal
wire segment 50 in one embodiment having a first section 52 of a
uniform cross-section and a second section 54 having a distally
tapering cross-section. In an exemplary embodiment, the first
section 52 has a length of about 3.0 millimeters and an as-cut
cross-sectional dimension of about 0.0045 inches by about 0.003
inches, and whereas the second section 54 has a length of about 4.0
millimeters and tapers to a distal-most, as-cut, cross-sectional
dimension of about 0.002 inches by about 0.003 inches.
Post-polishing of the device generally involves an etching process
that typically results in a 40% to 50% reduction in the as-cut
cross-sectional dimensions. In another embodiment, as depicted in
FIG. 3, the distal wire segment 50 is bound by a spring member 57
of a uniform diameter and is equipped with an atruamatic distal tip
58. In alternative embodiments, the spring element 57 and/or the
atraumatic tip 58 are made or coated with of a radiopaque material,
such as, for example, platinum.
[0122] FIG. 28b illustrates an alternative distal wire segment
construction. As depicted, the distal wire segment 4010 includes a
first section 4011a and a second section 4011b, the second section
4011b having a width W greater than the width of the first section
4011a. In one implementation a tapered transition section 4012
joins the first and second sections 4011a and 4011b. In one
implementation the width W of the second section is between about
0.003 inches and about 0.004 inches with the length L between the
distal end 4013 of the expandable member 4014 and the second
section 4011b of the wire segment 4010 being between about 0.015
inches and about 0.020 inches. An advantage of the inclusion of the
second section 4011b is that the greater width dimension provides a
larger surface area for bonding a coil/spring segment 57 to the
wire segment 4010. In one implementation the first section 4011a
has a circular or substantially circular construction and the
second section 4011b has a flat profile formed by a
pressing/coining operation.
[0123] In one embodiment, as will be described in more detail
below, the expandable member 12 is delivered to the treatment site
of a patient through the lumen of a delivery catheter that has been
previously placed at the treatment site. In an alternative
embodiment, the vascular treatment device 10 includes a sheath that
restrains the expandable member 12 in a compressed state during
delivery to the treatment site and which is proximally retractable
to cause the expandable member 12 to assume an expanded state.
[0124] In one implementation, the expandable member 12 in the
expanded state is able to engage an embolic obstruction residing at
the treatment site, for example by embedding itself into the
obstruction, and is removable from the patient by pulling on a
portion of the elongate flexible wire 40 residing outside the
patient until the expandable member 12 and at least a portion of
the embolic obstruction are removed from the patient.
[0125] The use of interconnected and out-of-phase undulating
elements 24 to create at least some of the cell structures 26 in
alternative embodiments provides several advantages. First, the
curvilinear nature of the cell structures 26 enhances the
flexibility of the expandable member 12 during its delivery through
the tortuous anatomy of the patient to the treatment site. In
addition, the out-of-phase relationship between the undulating
elements facilitates a more compact nesting of the expandable
member elements permitting the expandable member 12 to achieve a
very small compressed diameter. A particular advantage of the
expandable member strut pattern shown in FIG. 1A, and various other
embodiments described herein, is that they enable sequential
nesting of the expandable member elements which permit the
expandable members to be partially or fully deployed and
subsequently withdrawn into the lumen of a delivery catheter. The
out-of-phase relationship also results in a diagonal orientation of
the cell structures 26 which may induce a twisting action as the
expandable member 12 transitions between the compressed state and
the expanded state that helps the expandable member to better
engage with the embolic obstruction. In alternative embodiments,
the cell structures 26 of the expandable member 12 are specifically
arranged to produce a desired twisting action during expansion of
the expandable member 12. In this manner, different expandable
members each having different degrees of twisting action may be
made available to treat, for example, different types of embolic
obstructions.
[0126] To enhance visibility of the device under fluoroscopy, the
expandable member may be fully or partially coated with a
radiopaque material, such as tungsten, platinum, platinum/iridium,
tantalum and gold. Alternatively, or in conjunction with the use of
a radiopaque coating, radiopaque markers 60 may be positioned at or
near the proximal and distal ends 20 and 22 of the expandable
device and/or along the proximal and distal wire segments 42 and 50
and/or on selected expandable member strut segments. In one
embodiment, the radiopaque markers 60 are radiopaque coils, such as
platinum coils.
[0127] FIG. 4A depicts a vascular treatment device 100 in a
two-dimensional plane view in another embodiment of the present
invention. In its manufactured and/or expanded tubular
configuration, device 100 has a similar construction as device 10
shown in FIG. 1B. Like device 10 described above in conjunction
with FIGS. 1A and 1B, device 100 includes a self-expandable member
112 that is coupled to an elongate flexible wire 140. The
expandable member 112 includes a proximal end portion 114, a
cylindrical main body portion 116 and a distal end portion 118. As
mentioned above, delivery of the expandable member 112 in its
unexpanded state to the treatment site of a patient is accomplished
in one manner by placing the expandable member 112 into the
proximal end of a delivery catheter and pushing the expandable
member 112 through the lumen of the delivery catheter until it
reaches a distal end of the catheter that has been previously
placed at or across the treatment site. The proximally extending
elongate flexible wire 140 which is attached to or coupled to the
proximal end 120 of the expandable member 112 is designed to
transmit a pushing force applied to it to its connection point with
the elongate flexible member 112. As shown in FIG. 4A, and in more
detail in FIG. 4B, device 100 is distinguishable from the various
embodiments of device 10 described above in that the proximal-most
cell structures 128 and 130 in the proximal end portion 114 include
strut elements having a width dimension W1 larger than the width
dimension W2 of the other strut elements within the expandable
member 112. As shown, the proximal-most wall sections 160, 162 and
164 of cell structures 128 are made of struts having width W1.
Moreover, all the struts of the proximal-most cell structure 130
have an enhanced width W1. The inclusion and placement of the
struts with width W1 provides several advantages. One advantage is
that they permit the push force applied by the distal end of the
elongate wire 140 to the proximal end 120 of elongate member 112 to
be more evenly distributed about the circumference of the
expandable member 112 as it is being advanced through the tortuous
anatomy of a patient. The more evenly distributed push force
minimizes the formation of localized high force components that
would otherwise act on individual or multiple strut elements within
the expandable member 112 to cause them to buckle. Also, by
including the struts of width W1 in the peripheral regions of
proximal end portion 114, they greatly inhibit the tendency of the
proximal end portion 114 to buckle under the push force applied to
it by elongate wire 140. In one exemplary embodiment the as-cut
width dimension W1 is about 0.0045 inches and the as-cut width
dimension W2 is about 0.003 inches. As discussed above,
post-polishing of the device generally involves an etching process
that typically results in a 40% to 50% reduction in the as-cut
cross-sectional dimensions.
[0128] It is important to note that although the width dimension W1
is shown as being the same among all struts having an enhanced
width, this is not required. For example, in one embodiment wall
segments 158 may have an enhanced width dimension greater than the
enhanced width dimension of wall segments 160, and wall segments
160 may have an enhanced width dimension greater than the enhanced
width dimension of wall segments 162, and so on. Moreover, the
inner strut elements 166 of the proximal-most cell structure 130
may have an enhanced width dimension less than the enhanced width
dimensions of struts 158. Also, in alternative embodiments, the
radial thickness dimension of struts 158, 160, 162, 164, etc. may
be enhanced in lieu of the width dimension or in combination
thereof.
[0129] In yet another embodiment, as shown in FIG. 5, some of the
strut elements 180 in the distal end portion 118 of the expandable
member 112 have a mass greater than that of the other struts to
resist buckling and possible breaking of the struts as device 100
is advanced to a treatment site of a patient. In the embodiment
shown, struts 180 are dimensioned to have the same width as distal
wire segment 150. In alternative embodiments, the thickness
dimension of struts 180 may be enhanced in lieu of the width
dimension or in combination thereof.
[0130] FIGS. 6A and 6B illustrate a vascular treatment device 200
in accordance with another embodiment of the present invention.
FIG. 6A depicts device 200 in a two-dimensional plane view as if
the device were cut and laid flat on a surface. FIG. 6B depicts the
device in its manufactured and/or expanded tubular configuration.
Device 200 includes an expandable member 212 having a proximal end
portion 214, a cylindrical main body portion 216 and a distal end
portion 218 with an elongate flexible wire 240 attached to or
otherwise coupled to the proximal end 220 of the expandable member.
The construction of device 200 is similar to device 100 described
above in conjunction with FIGS. 4A except that the proximal wall
segments 260 of cell structures 228 and 230 comprise linear or
substantially linear strut elements as viewed in the two dimension
plane view of FIG. 6A. In one embodiment, the linear strut elements
260 are aligned to form continuous and substantially linear rail
segments 270 that extend from the proximal end 220 of proximal end
portion 214 to a proximal-most end of main body portion 216 (again,
as viewed in the two dimension plane view of FIG. 6A) and
preferably are of the same length, but may be of different lengths.
When the pattern of FIG. 6A is applied to laser cutting a tubular
structure, the resulting expandable member configuration is that as
shown in FIG. 6B. As shown in FIG. 6B, rail segments 270 are not in
fact linear but are of a curved and non-undulating shape. This
configuration advantageously provides rail segments 270 devoid of
undulations thereby enhancing the rail segments' ability to
distribute forces and resist buckling when a push force is applied
to them. In alternative preferred embodiments, the angle .theta.
between the wire segment 240 and rail segments 270 ranges between
about 140 degrees to about 150 degrees. In one embodiment, one or
both of the linear rail segments 270 have a width dimension W1
which is greater than the width dimension of the adjacent strut
segments of cell structures 228 and 230. An enhanced width
dimension W1 of one or both the linear rail segments 270 further
enhances the rail segments' ability to distribute forces and resist
buckling when a push force is applied to them. In another
implementation, one or both of the linear rail segments 270 are
provided with an enhanced thickness dimension, rather than an
enhanced width dimension to achieve the same or similar result. In
yet an alternative implementation, both the width and thickness
dimensions of one or both of the linear rail segments 270 are
enhanced to achieve the same or similar results. In yet another
implementation, the width and/or thickness dimensions of each of
the rail segments 270 differ in a manner that causes a more even
compression of the proximal end portion 214 of the expandable
member 212 when it is loaded or retrieved into a delivery catheter
or sheath (not shown).
[0131] FIGS. 7A and 7B illustrate a vascular treatment device 300
in accordance with another embodiment of the present invention.
FIG. 7A depicts device 300 in a two-dimensional plane view as if
the device were cut and laid flat on a surface. FIG. 7B depicts the
device in its manufactured and/or expanded tubular configuration.
Device 300 includes an expandable member 312 having a proximal end
portion 314, a cylindrical main body portion 316 and a distal end
portion 318 with an elongate flexible wire 340 attached to or
otherwise coupled to the proximal end 320 of the expandable member.
The construction of device 300 is similar to device 200 described
above in conjunction with FIGS. 6A and 6B except that the
proximal-most cell structure 330 comprises a substantially diamond
shape as viewed in the two-dimensional plane of FIG. 7A. The
substantially diamond-shaped cell structure includes a pair of
outer strut elements 358 and a pair of inner strut elements 360,
each having an enhanced width and/or enhanced thickness dimension
as previously discussed in conjunction with the embodiments of
FIGS. 4 and 6. In alternative preferred embodiments, the inner
strut elements 360 intersect the outer strut elements 358 at an
angle .beta. between about 25.0 degrees to about 45.0 degrees as
viewed in the two-dimensional plane view of FIG. 7A. Maintaining
the angular orientation between the inner and outer struts within
in this range enhances the pushabilty of the expandable member 312
without the occurrence of buckling and without substantially
affecting the expandable member's ability to assume a very small
compressed diameter during delivery.
[0132] In one embodiment, the inner strut elements 360 have a mass
less than that of the outer strut elements 358 that enables them to
more easily bend as the expandable member 312 transitions from an
expanded state to a compressed state. This assists in achieving a
very small compressed diameter. In another embodiment, as shown in
FIG. 7C, the inner strut elements 360 are coupled to the outer
strut elements 358 by curved elements 361 that enable the inner
strut elements 360 to more easily flex when the expandable member
312 is compressed to its delivery position.
[0133] FIG. 8 illustrates an alternative embodiment of a vascular
treatment device 400. Device 400 has a similar construction to that
of device 200 depicted in FIGS. 6A and 6B with the exception that
the expandable member 412 of device 400 is connected at its
proximal end portion 414 with two distally extending elongate
flexible wires 440 and 441. As illustrated, wire 440 is attached to
or otherwise coupled to the proximal-most end 420 of proximal end
portion 414, while wire 441 is attached to or otherwise coupled to
the distal-most end 422 of the proximal end portion 414 at the
junction with rail segment 470. In yet another embodiment, an
additional elongate flexible wire (not shown) may be attached to
the distal-most end 424. The use of two or more elongate flexible
wires 440 and 441 to provide pushing forces to the proximal end
portion 414 of elongate member 412 advantageously distributes the
pushing force applied to the proximal end portion 414 to more than
one attachment point.
[0134] FIG. 10 illustrates a two-dimensional plane view of a
vascular treatment device 500 in another embodiment of the present
invention. In the embodiment of FIG. 10, expandable member 512
includes a plurality of generally longitudinal undulating elements
524 with adjacent undulating elements being out-of-phase with one
another and connected in a manner to form a plurality of diagonally
disposed cell structures 526. The expandable member 512 includes a
cylindrical portion 516 and a distal end portion 518 with the cell
structures 526 in the main body portion 516 extending continuously
and circumferentially around a longitudinal axis 530 of the
expandable member 512. The cell structures 526 in the distal end
portion 518 extend less than circumferentially around the
longitudinal axis 530 of the expandable member 512. Attached to or
otherwise coupled to each of the proximal-most cell structures 528
are proximally extending elongate flexible wires 540. The use of
multiple elongate flexible wires 540 enables the pushing force
applied to the proximal end of the expandable member 512 to be more
evenly distributed about its proximal circumference. In another
embodiment, although not shown in FIG. 10, the proximal-most strut
elements 528 have a width and/or thickness greater than the struts
in the other portions of the expandable member 512. Such a feature
further contributes to the push force being evenly distributed
about the circumference of the expandable member 512 and also
inhibits the strut elements directly receiving the push force from
buckling.
[0135] FIGS. 11A and 11B illustrate a vascular treatment device 600
in accordance with another embodiment of the present invention.
FIG. 11A depicts device 600 in a two-dimensional plane view as if
the device were cut and laid flat on a surface. FIG. 11B depicts
the device in its manufactured and/or expanded tubular
configuration. In the embodiment of FIGS. 11A and 11B, expandable
member 612 includes a plurality of generally longitudinal
undulating elements 624 with adjacent undulating elements being
interconnected by a plurality of curved connectors 628 to form a
plurality of closed-cell structures 626 disposed about the length
of the expandable member 612. In the embodiment shown, the
expandable member 612 includes a proximal end portion 614 and a
cylindrical portion 616 with the cell structures 626 in the
cylindrical portion 616 extending continuously and
circumferentially around a longitudinal axis 630 of the expandable
member 612.
[0136] The cell structures 626 in the proximal end portion 614
extend less than circumferentially around the longitudinal axis 630
of the expandable member 612. In an alternative embodiment, the
expandable member 612 includes a proximal end portion, a
cylindrical main body portion and a distal end portion, much like
the expandable member 12 depicted in FIGS. 1A and 1B. In such an
embodiment, the cell structures 626 in the distal end portion of
the expandable member would extend less than circumferentially
around the longitudinal axis 630 of the expandable member 612 in a
manner similar to the proximal end portion 614 shown in FIG. 11A.
Moreover, it is appreciated that the expandable members of FIGS.
1A, 4A, 6A, 7A, 7C, 10, 14, 15 and 19-24 may be modified in a way
so as to eliminate the distal end portion (e.g., distal end portion
18 in FIG. 1A) so that there exists only a proximal end portion and
main body portion like that of FIG. 11A.
[0137] FIG. 12 illustrates a vascular treatment device 700 in
accordance with another embodiment of the present invention. FIG.
12 depicts device 700 in a two-dimensional plane view as if the
device were cut and laid flat on a surface. In the embodiment of
FIG. 12, expandable member 712 includes a plurality of generally
longitudinal undulating elements 724 with adjacent undulating
elements being interconnected by a plurality of curved connectors
728 to form a plurality of closed-cell structures 726 disposed
about the length of the expandable member 712. In the embodiment
shown, the expandable member 712 includes a cylindrical portion 716
and a distal end portion 718 with the cell structures 726 in the
cylindrical portion 716 extending continuously and
circumferentially around a longitudinal axis 730 of the expandable
member 712. The cell structures 726 in the distal end portion 718
extend less than circumferentially around the longitudinal axis 730
of the expandable member 712. In a manner similar to that described
in conjunction with the embodiment of FIG. 10, attached to or
otherwise coupled to each of the proximal-most cell structures 728
are proximally extending elongate flexible wires 740. This
arrangement enables the pushing force applied to the proximal end
of the expandable member 712 to be more evenly distributed about
its proximal circumference. In another embodiment, although not
shown in FIG. 12, the proximal-most strut elements 730 have a width
and/or thickness greater than the struts in the other portions of
the expandable member 712. Such a feature further contributes to
the push force being evenly distributed about the circumference of
the expandable member 712 and also inhibits the strut elements
directly receiving the push force from buckling.
[0138] As previously discussed, in use, the expandable members of
the present invention are advanced through the tortuous vascular
anatomy of a patient to a treatment site, such as an embolic
obstruction, in an unexpanded or compressed state of a first
nominal diameter and are movable from the unexpanded state to a
radially expanded state of a second nominal diameter greater than
the first nominal diameter for deployment at the treatment site.
One manner of delivering and deploying expandable member 912 at the
site of an embolic obstruction 950 is shown in FIGS. 13A through
13C. As shown in FIG. 13A, a delivery catheter 960 having an inner
lumen 962 is advanced to the site of the embolic obstruction 950 so
that its distal end 964 is positioned distal to the obstruction.
After the delivery catheter 960 is in position at the embolic
obstruction 950, the retrieval device 900 is placed into the
delivery catheter by introducing the expandable member 912 into a
proximal end of the delivery catheter (not shown) and then
advancing the expandable member 912 through the lumen 962 of the
delivery catheter by applying a pushing force to elongate flexible
wire 940. By the use of radiopaque markings and/or coatings
positioned on the delivery catheter 960 and device 900, the
expandable member 912 is positioned at the distal end of the
delivery catheter 960 as shown in FIG. 13B so that the main body
portion 916 is longitudinally aligned with the obstruction 950.
Deployment of the expandable member 912 is achieved by proximally
withdrawing the delivery catheter 960 while holding the expandable
member 912 in a fixed position as shown in FIG. 13C. Once the
expandable member 912 has been deployed to an expanded position
within the obstruction 950, the expandable member 912 is retracted,
along with the delivery catheter 960, to a position outside the
patient. In one embodiment, the expandable member 912 is first
partially retracted to engage with the distal end 964 of the
delivery catheter 960 prior to fully retracting the devices from
the patient.
[0139] In one embodiment, once the expandable member 912 is
expanded at the obstruction 950, it is left to dwell there for a
period of time in order to create a perfusion channel through the
obstruction that causes the obstruction to be lysed by the
resultant blood flow passing through the obstruction. In such an
embodiment, it is not necessary that the expandable member 912
capture a portion of the obstruction 950 for retrieval outside the
patient. When a sufficient portion of the obstruction 950 has been
lysed to create a desired flow channel through the obstruction, or
outright removal of the obstruction is achieved by the resultant
blood flow, the expandable member 912 may be withdrawn into the
delivery catheter 960 and subsequently removed from the
patient.
[0140] In another embodiment, the expandable member 912 is expanded
at the obstruction 950 and left to dwell there for a period of time
in order to create a perfusion channel through the obstruction that
causes the obstruction to be acted on by the resultant flow in a
manner that makes the embolic obstruction more easily capturable by
the expandable member and/or to make it more easily removable from
the vessel wall of the patient. For example, the blood flow created
through the embolic obstruction may be made to flow through the
obstruction for a period of time sufficient to change the
morphology of the obstruction that makes it more easily captured by
the expandable member and/or makes it more easily detachable from
the vessel wall. As in the preceding method, the creation of blood
flow across the obstruction 950 also acts to preserve tissue. In
one embodiment, the blood flow through the obstruction may be used
to lyse the obstruction. However, in this modified method, lysing
of the obstruction is performed for the purpose of preparing the
obstruction to be more easily captured by the expandable member
912. When the obstruction 950 has been properly prepared, for
example by creating an obstruction 950 of a desired nominal inner
diameter, the expandable member 912 is deployed from the distal end
964 of the delivery catheter 940 to cause it to engage with the
obstruction. Removal of all, or a portion, of the obstruction 950
from the patient is then carried out in a manner similar to that
described above.
[0141] In yet another embodiment, once the expandable member 912
has been delivered and expanded inside the obstruction 950, it may
be detached from the elongate wire 940 for permanent placement
within the patient. In such an embodiment, the manner in which the
elongate wire 940 is attached to the expandable member 912 allows
the two components to be detached from one another. This may be
achieved, for example, by the use of a mechanical interlock or an
erodable electrolytic junction between the expandable member 912
and the elongate wire 940.
[0142] As described herein, the expandable members of the various
embodiments may or may not include distal wire segments that are
attached to their distal ends. In alternative preferred
embodiments, vascular treatment devices that are configured to
permanently place an expandable member at the site of an embolic
obstruction do not include distal wire segments attached to the
distal ends of the expandable members.
[0143] One advantage associated with the expandable member cell
patterns of the present invention is that withdrawing the
expandable members by the application of a pulling force on the
proximal elongate wire flexible wire urges the expandable members
to assume a smaller expanded diameter while being withdrawn from
the patient, thus decreasing the likelihood of injury to the vessel
wall. Also, during clot retrieval as the profile of the expandable
members decrease, the cell structures collapse and pinch down on
the clot to increase clot retrieval efficacy. Another advantage is
that the cell patterns permit the expandable members to be
retracted into the lumen of the delivery catheter after they have
been partially or fully deployed. As such, if at any given time it
is determined that the expandable member has been partially or
fully deployed at an improper location, it may be retracted into
the distal end of the delivery catheter and repositioned to the
correct location.
[0144] With reference to FIG. 14, a modified version of the
vascular treatment device 200 of FIG. 6A is shown that includes
thin strut elements 280 intersecting at least some of the cell
structures 226 located in the cylindrical main body portion 216 of
expandable member 212. The thin strut elements 280 are dimensioned
to have a width of less than the strut elements 282 that form the
cell structures 226. In alternative exemplary embodiments, strut
elements 280 have an as-cut or polished width dimension that is
between about 25% to about 50% smaller than the respective as-cut
or polished width dimension of struts 262. When used for the
purpose of clot retrieval, a purpose of the thin struts 280 is to
enhance the expandable member's ability to engage with and capture
an embolic obstruction. This is accomplished by virtue of several
factors. First, the thinner width dimensions of the struts 280 make
it easier for the struts to penetrate the obstruction. Second, they
act to pinch portions of the entrapped obstruction against the
outer and wider strut elements 282 as the expandable member is
deployed within the obstruction. Third, they may be used to locally
enhance radial forces acting on the obstruction. It is important to
note that the use of thin strut elements 280 is not limited to use
within cell structures 226 that reside within the cylindrical main
body portion 216 of the expandable member 212. They may be
strategically positioned in any or all of the cell structures of
the expandable member. Moreover, it is important to note that the
use of thin strut elements 280 is not limited to the embodiment of
FIGS. 6, but are applicable to all the various embodiments
disclosed herein. Lastly, in alternative exemplary embodiments, as
shown in FIG. 15, multiple thin strut elements 280 are provided
within one or more of the cell structures 226, and may also be used
in conjunction with cell structures that have a single thin strut
element and/or cell structures altogether devoid of thin strut
elements.
[0145] In the treatment of aneurysms when the treatment device is
used for the purpose of diverting flow, the density of the cell
structures 226 is sufficient to effectively divert flow away from
the aneurysm sack. In alternative embodiments in lieu of, or in
combination with adjusting the density of the cell structures 226,
intermediate strut elements similar to the strut elements 280 of
FIGS. 14 and 15 are used to increase the effective wall surface of
the expandable member. In these embodiments, the intermediate strut
elements may have the same, smaller, larger, or any combination
thereof, dimensional characteristics of the cell structure struts.
Conversely, in alternative embodiments for use in the treatment of
aneurysms for the purpose placing coils or other like structures
within the sack of the aneurysm, the size of the cell structures
226 is sufficient to facilitate passage of the coils through the
cell structures.
[0146] FIG. 16 illustrates a treatment device according to the
embodiment of FIGS. 6A and 6B, wherein the pushability of the
expandable member 212 during its advancement to the treatment site
of a patient is enhanced by the inclusion of an internal wire
segment 241 that extends between the proximal end 220 and distal
end 222 of the expandable member 212. In this manner, the pushing
force applied by elongate wire 240 is transmitted to both the
proximal and distal ends of expandable device. The internal wire
segment may be a discrete element that is attached to the proximal
and distal ends of the expandable member, or may preferably be a
co-extension of the elongate flexible wire 240. During delivery of
the expandable member 212 to the treatment site in its compressed
state, the internal wire segment 241 assumes a substantially
straight or linear configuration so as to adequately distribute at
least a part of the pushing force to the distal end 222 of the
expandable member. When the expandable member 212 expands, it tends
to foreshorten causing slack in the internal wire segment 241 that
forms a long-pitched helix within the expandable member as shown in
FIG. 16. An additional advantage associated with the use the
internal wire segment 241 is that the formation of the internal
helix upon expansion of the expandable member 212 assists in
capturing the embolic obstruction.
[0147] In an alternative embodiment, as shown in FIG. 17, the
pushability of the expandable member 212 during its advancement to
the treatment site of a patient is enhanced by the inclusion of an
external wire segment 243 that extend between the proximal end 220
and distal end 222 of the expandable member 212. In this manner,
the pushing force applied by the elongate wire 240 is transmitted
to both the proximal and distal ends of the expandable device. The
external wire segment may be discrete element that is attached to
the proximal and distal ends of the expandable member, or may
preferably be a co-extension of the elongate flexible wire 240.
During delivery of the expandable member 212 to the treatment site
in its compressed state, the external wire segment 243 assumes a
substantially straight or linear configuration so as to adequately
distribute at least a part of the pushing force to the distal end
222 of the expandable member. When the expandable member 212
expands, it tends to foreshorten causing slack in the external wire
segment 243 as shown in FIG. 17. An additional advantage associated
with the use of the external wire segment 243 is that it directly
acts on the obstruction while the expandable member 212 is expanded
to assist in engaging and capturing the embolic obstruction.
[0148] In yet another embodiment, a distal emboli capture device
251 is disposed on the distal wire segment 250, or otherwise
attached to the distal end 222, of expandable member 212 as shown
in FIG. 18. The function of the distal emboli capture device 251 is
to capture emboli that may be dislodged from the embolic
obstruction during the expansion of the expandable member 212 or
during its removal from the patient to prevent distal embolization.
In FIG. 18, the distal emboli capture device is shown as a coil. In
alternative embodiments, baskets, embolic filters or other known
emboli capture devices may be attached to the distal end 222 or
distal wire segment 250 of expandable member 12.
[0149] Again, as with the embodiments of FIGS. 14 and 15, it is
important to note that the features described in conjunction with
FIGS. 16, 17 and 18 are not limited to the embodiment of FIGS. 6,
but are applicable to all the various embodiments disclosed
herein.
[0150] FIG. 19 illustrates a bodily duct or vascular treatment
device 1000 in accordance with another embodiment of the present
invention. FIG. 19 depicts device 1000 in a two-dimensional plane
view as if the device were cut and laid flat on a surface. Device
1000 includes an expandable member 1012 having a proximal end
portion 1024, a cylindrical main body portion 1026 and a distal end
portion 1028 with an elongate flexible wire 1014 attached to or
otherwise coupled to the proximal end 1020 of the expandable
member. The construction of device 1000 is similar to device 200
described above in conjunction with FIGS. 6A except that the cell
structures 1018 and 1019 in the proximal end portion 1024 are more
closely symmetrically arranged than the cell structures in the
proximal end portion 214 of device 200. The more substantial
symmetrical arrangement of the cell structures in the proximal end
portion 1024 of device 1000 facilitates the loading or retrieval of
the expandable member 1012 into a lumen of a delivery catheter or
sheath (not shown) by causing the proximal end portion 1024 to
collapse more evenly during compression. The proximal wall segments
1016 of cell structures 1018 and 1019 comprise linear or
substantially linear strut elements as viewed in the two dimension
plane view of FIG. 19. In one embodiment, the linear strut elements
1016 are aligned to form continuous and substantially linear rail
segments 1017 that extend from the proximal end 1020 of proximal
end portion 1024 to a proximal-most end of main body portion 1026
(again, as viewed in the two dimension plane view of FIG. 19) and
preferably are of the same length. In alternative embodiments, the
angle .theta. between the wire segment 1014 and rail segments 1017
ranges between about 140 degrees to about 150 degrees. In one
embodiment, one or both of the linear rail segments 1017 have a
width dimension W1 which is greater than the width dimension of the
adjacent strut segments of cell structures 1018 and/or 1019 and/or
1030. An enhanced width dimension W1 of one or both the linear rail
segments 1017 further enhances the rail segments' ability to
distribute forces and resist buckling when a push force is applied
to them. In another implementation, one or both of the linear rail
segments 1017 are provided with an enhanced thickness dimension,
rather than an enhanced width dimension to achieve the same or
similar result. In yet an alternative implementation, both the
width and thickness dimensions of one or both of the linear rail
segments 1017 are enhanced to achieve the same or similar results.
In yet another implementation, the width and/or thickness
dimensions of each of the rail segments 1017 differ in a manner
that causes a more even compression of the proximal end portion
1024 of the expandable member 1012 when it is collapsed as it is
loaded or retrieved into a delivery catheter or sheath.
[0151] Although the description that follows is directed to the
embodiment of FIG. 19, it is important to note that the provision
of a slit as contemplated by the embodiments of FIGS. 20-22 are
applicable to all the vascular treatment devices described herein,
and their numerous embodiments and modifications thereof.
[0152] Turning now to FIG. 20, the treatment device 1000 of FIG. 19
is depicted having a longitudinal slit 1040 that extends from the
proximal end 1020 to the distal end 1022 of the expandable member
1012. The slit 1040 permits the cell structures 1018, 1019 and 1030
to move relative to one another in a manner that inhibits the
individual strut elements 1032 of the expandable member 1012 from
buckling during compression of the expandable member 1012 as it is
loaded or retrieved into a delivery catheter or sheath. In
alternative embodiments, slit 1040 extends less than the entire
length of expandable member 1012 and is arranged to inhibit
buckling of strategically important strut elements that most affect
the expandable member's ability to be effectively loaded or
withdrawn into a delivery catheter or sheath. For example, in one
embodiment, slit 1040 is provided only in the proximal end portion
1024 of the expandable member 1012 where the likelihood of buckling
or bending of struts 1032 is most likely to occur. In another
embodiment, slit 1040 is provided in both the proximal end portion
1024 and the cylindrical main body portion 1026 of expandable
member 1012.
[0153] FIG. 21 illustrates the treatment device 1000 of FIG. 19
having a diagonally disposed/spiral slit 1050 that extends the
entire circumference of the expandable member 1012. In one
embodiment, as illustrated in FIG. 21, the spiral slit 1050
originates at the distal position, or at a point adjacent to the
distal position, of the proximal end portion 1024 of expandable
member 1012. With respect to the embodiments having linear rail
segments, such as the linear rail segments 1017 of FIG. 19, the
spiral slit 1050 originates at the distal position 1021 of one of
the linear rail segments 1017, or at a point distally adjacent to
the distal position 1021, as shown in FIG. 21. Testing of the
various vascular treatment devices described herein has shown that
the occurrence of buckling tends to occur at the strut elements
located adjacent to the distal positions of the proximal end
portions of the expandable members. This phenomenon is exacerbated
in the expandable members having proximal end portions with linear
rail segments. For this reason, and with reference to FIG. 21, the
originating point of spiral slit 1050 is located at or adjacent to
a distal position 1021 of one of the linear rail segments 1017. An
advantage of the diagonally disposed and/or spiral slit
configuration of FIG. 21 is that it originates where the buckling
tends to originate and further inhibits buckling of strut elements
1032 along the length of the expandable member 1012. As shown in
FIG. 22, in alternative embodiments slit 1050 extends diagonally
along only a portion of the circumference of the cylindrical main
body portion 1026 of the expandable member 1012. In the embodiment
of FIG. 22, slit 1050 originates at the distal position 1021 of
linear rail segment 1017. In alternative embodiments, where
buckling of individual strut elements 1032 originate at a point
other than at the distal point of the proximal end portion 1024 of
the expandable member 1012, the originating point of the slit 1050
is located at the origination point of the bucking (absent the slit
1050) and extends in a longitudinal direction distally
therefrom.
[0154] FIG. 23 illustrates a bodily duct or vascular treatment
device 2000 in accordance with an embodiment of the present
invention. FIG. 23 depicts device 2000 in a two-dimensional plane
view as if the device were cut and laid flat on a surface. Device
2000 includes a self-expandable member 2012 that is attached or
otherwise coupled to an elongate flexible wire 2040 that extends
proximally from the expandable member 2012. In one embodiment, the
expandable member 2012 is made of shape memory material, such as
Nitinol, and is preferably laser cut from a tube. In one
embodiment, the expandable member 2012 has an integrally formed
proximally extending wire segment 2042 that is used to join the
elongate flexible wire 2040 to the expandable member 2012. In such
an embodiment, flexible wire 2040 may be joined to wire segment
2042 by the use of solder, a weld, an adhesive, or other known
attachment method. In an alternative embodiment, the distal end of
flexible wire 2040 is attached directly to a proximal end 2020 of
the expandable member 2012.
[0155] In the embodiment of FIG. 23, expandable member 2012
includes a plurality of generally longitudinal undulating elements
2024 with adjacent undulating elements being coupled to one another
in a manner to form a plurality of circumferentially-aligned cell
structures 2026. The expandable member 2012 includes a proximal end
portion 2013, a cylindrical main body portion 2014 and a distal end
portion 2015 with the cell structures 2026 in the main body portion
2014 extending continuously and circumferentially around a
longitudinal axis 2032 of the expandable member 2012. The cell
structures in the proximal end portion 2013 and distal end portion
2015 extend less than circumferentially around the longitudinal
axis 2032 of the expandable member 2012. The proximal wall segments
2016 of cell structures 2027, 2028, 2029 and 2030 comprise linear
or substantially linear strut elements as viewed in the two
dimension plane view of FIG. 23. In one embodiment, the linear
strut elements 2016 are aligned to form continuous and
substantially linear rail segments 2017 that extend from the
proximal end 2020 of proximal end portion 2013 to a proximal-most
end of main body portion 2014 (again, as viewed in the two
dimension plane view of FIG. 23) and preferably are of the same
length. As described above in conjunction with FIGS. 6A and 6B,
rail segments 2017 are not in fact linear but are of a curved and
non-undulating shape. This configuration advantageously provides
rail segments 2017 devoid of undulations thereby enhancing the rail
segments' ability to distribute forces and resist buckling when a
push force is applied to them. In alternative preferred
embodiments, the angle .theta. between the wire segment 2042 or
2040, which ever the case may be, and rail segments 2017 ranges
between about 140 degrees to about 150 degrees. In one embodiment
the linear rail segments 2017 have a width dimension which is
greater than the width dimension of the adjacent strut segments of
cell structures 2027 and/or 2028 and/or 2029 and/or 2030 and/or
2026. An enhanced width of the linear rail segments 2017 further
enhances the rail segments' ability to distribute forces and resist
buckling when a push force is applied to the expandable member. In
another implementation the linear rail segments 2017 are provided
with an enhanced thickness dimension, rather than an enhanced width
dimension to achieve the same or similar result. In yet an
alternative implementation, both the width and thickness dimensions
of the linear rail segments 2017 are enhanced to achieve the same
or similar results.
[0156] In one embodiment, the width and/or thickness of the
internal strut elements 2080 of proximal-most cell structure 2027
is also enhanced so as to resist buckling of these elements while
the expandable member is being pushed through a sheath or delivery
catheter. In one exemplary embodiment, the "as-cut" nominal widths
of the enhanced strut elements 2016 and 2080 are about 0.0045
inches, while the "as-cut" nominal width of the other strut
elements are about 0.003 inches.
[0157] FIGS. 24A and 24B illustrate a vascular treatment device
3000 of another embodiment of the present invention. FIG. 24A
depicts device 3000 in a two-dimensional plane view as if the
device were cut and laid flat on a surface. FIG. 24B depicts the
device in its manufactured and/or expanded tubular configuration.
The overall design of device 3000 is similar to the design of
device 2000 depicted and described above in reference to FIG. 23.
The primary difference between the two designs lays in the length
"L" to width "W" ratio of the cell structures 2026, 2027, 2028,
2029 and 2030. The length to width ratios of the cells structures
of FIG. 24A are generally greater than the length to width ratios
of the respective cell structures of FIG. 23. As illustrated, the
lengths "L" of the cell structures of the device of FIG. 24A, in
the "as-cut" configuration are generally greater than the lengths
of the respective cell structures of FIG. 23, while the widths "W"
of the cell structures of the device of FIG. 24A are generally
smaller than the width of the respective cell structures of FIG.
23. As a result, the slope of the individual strut elements 2040 in
the cell structures of FIG. 24A are generally smaller than the
slopes of the respective strut elements in the cell structures of
FIG. 23. By reducing the slope of the strut elements 2040 and
leaving the other dimensional and material characteristics
constant, the effective radial force along the length of the struts
2040 is reduced. The effect of such a reduction is that the
summation of axial force components along lines A-A of the device
of FIG. 24 more closely matches the summation of the radial force
components along lines B-B as compared to the device of FIG. 23.
Through experimentation, the inventors have discovered that an
"as-cut" cell structure length to width ratio of greater than about
2.0, and an "expanded" cell structure length to width ratio of a
greater than about 1.25, advantageously resulted in a longitudinal
radial force distribution along the length of the expandable member
2012 that enhanced the expandable member's ability to be pushed
through and withdrawn into a lumen of a delivery catheter.
[0158] FIGS. 26, 27A and 27B illustrate an expandable member 5000
in another implementation. Expandable member 5000 includes a
plurality of generally longitudinal undulating elements 5024 with
adjacent undulating elements being out-of-phase with one another
and connected in a manner to form a plurality of diagonally
disposed cell structures 5026 angularly disposed between about 40.0
to about 50.0 degrees with respect to one another. In one
implementation, the cell structures are diagonally displaced along
about a 45.0 degree line. The expandable member 5000 includes a
proximal end portion 5014, a cylindrical main body portion 5016 and
a distal end portion 5018 with the cell structures 5026 in the main
body portion 5016 extending continuously and circumferentially
around a longitudinal axis of the expandable member 5000. The cell
structures 5026 in the proximal end portion 5014 and distal end
portion 5018 extend less than circumferentially around the
longitudinal axis of the expandable member 5000. In one
implementation, the expandable member has an unexpanded or crimped
nominal diameter of about 1.0 millimeters and a designed maximum
implantable diameter of about 4.0 millimeters.
[0159] In one embodiment, expandable member 5000 has an overall
length dimension A of about 36.0.+-.2.0 millimeters with the main
body portion 5016 having a length P of about 19.0.+-.2.0
millimeters. In one implementation the strut width dimension N and
thickness dimension O within the main body portion 5016 are about
0.0021.+-.0.0004 inches and about 0.0032.+-.0.0005 inches,
respectively, while the strut width dimension L of the proximal
rails 5030 is about 0.0039.+-.0.004 inches.
[0160] In use, expandable member 5000 is advanced through the
tortuous vascular anatomy or bodily duct of a patient to a
treatment site in an unexpanded or compressed state (not shown) of
a first nominal diameter and is movable from the unexpanded state
to a radially expanded state of a second nominal diameter greater
than the first nominal diameter for deployment at the treatment
site. In alternative exemplary embodiments the first nominal
diameter (e.g., average diameter of main body portion 5016) ranges
between about 0.017 to about 0.030 inches, whereas the second
nominal diameter (e.g., average diameter of main body portion 5016)
is between about 2.5 to about 5.0 millimeters. In one
implementation, the dimensional and material characteristics of the
cell structures 5026 residing in the main body portion 5016 of the
expandable material 5000 are selected to produce sufficient radial
force and contact interaction to cause the cell structures 5026 to
engage with an embolic obstruction residing in the vascular in a
manner that permits partial or full removal of the embolic
obstruction from the patient. In other embodiments the dimensional
and material characteristics of the cell structures 5026 in the
main body portion 5016 are selected to produce a radial force per
unit length of between about 0.005 N/mm to about 0.050 N/mm,
preferable between about 0.010 N/mm to about 0.050 N/mm, and more
preferably between about 0.030 N/mm and about 0.050 N/mm. In one
embodiment, the diameter of the main body portion 5016 in a
designed fully expanded implanted state is about 4.0 millimeters
with the cell pattern, strut dimensions and material being selected
to produce a radial force of between about 0.030 N/mm to about
0.050 N/mm when the diameter of the main body portion is reduced to
1.5 millimeters. In the same or alternative embodiment, the cell
pattern, strut dimensions and material(s) are selected to produce a
radial force of between about 0.010 N/mm to about 0.020 N/mm when
the diameter of the main body portion is reduced to 3.0
millimeters.
[0161] In one implementation, as shown in the graph of FIG. 29, the
cell structures are constructed to have dimensional and material
characteristics to create an overall radial force exerted along the
length of the expandable member 5000 of between about 1.70N and
about 2.50N when the expandable member 5000 is in the compressed or
crimped state. About a -1.0N to a about a -1.7N overall reduction
in radial force along the length of the expandable member occurs
during about an initial 0.50 mm diametric range of expansion from
the compressed or crimped state. In a subsequent 0.5 mm diametric
range of expansion that follows the initial 0.5 mm of expansion,
about a -0.18N to about a -0.19N overall reduction in radial force
along the length of the expandable member occurs. Advantageously,
the expandable member 5000 exerts a relatively high radial force
during its initial expansion to enhance the likelihood that the
struts of expandable member engage an obstruction within the duct
of a patient upon initial deployment of the device. In addition,
the rate at which the radial force diminishes is initially much
greater during the initial expansion of the device than during
subsequent expansion. In the exemplary embodiment depicted by FIG.
29, the initial rate of reduction in the radial force during about
the first 0.5 mm of expansion is about 5.5 to 9.7 times greater
than the rate of reduction during the subsequent 0.5 mm of
expansion. An advantage of this radial force characteristic is that
high radial force values can be achieved during initial deployment
of the expandable member to enhance integration of the struts of
the expandable member into the duct obstruction with a subsequent
large reduction in radial force after the initial expansion, the
large reduction facilitating or enhancing the ability of the
obstruction to be removed from the duct of the patient without
complications and with limited adverse interactions with the duct
(e.g., less damage to the duct wall, etc.). Another advantage of
the radial force characteristics depicted in FIG. 29 is that during
subsequent expansions, the rate of decrease in the over radial
force along the length of the expandable member decreases in a
linear-like fashion at a much reduced rate providing a level of
predictability of the radial force being exerted at the different
expandable member diameters. Also, advantageously, the radial force
exerted by the expandable member is designed to achieve a non-zero
value when the expandable member is at a designed maximum
implantable diameter.
[0162] FIG. 30 illustrates clot retrieval devices 6000 according to
other implementations where, among other features, the strut
elements of rail segments 6001 and 6002 have varying width
dimensions. FIG. 30 depicts a clot retrieval device in a
two-dimensional plane view as if the device were cut and laid flat
on a surface. FIG. 30 depicts the device in its manufactured
(as-cut) configuration. In one implementation, rail segment 6001
transitions from a maximum width dimension at or near its proximal
end 6014 to a minimum width dimension at or near its distal end
6015. In a like manner, rail segment 6002 transitions from a
maximum width dimension at or near its proximal end 6014 to a
minimum width dimension at or near its distal end 6016. As
previously discussed, the width dimensions of the rail segments are
selected to enhance their ability to distribute forces and to
resist buckling when a push force is applied to the proximal end
6014 of the vascular treatment device. In some implementations the
percentage change between the maximum rail width dimension and the
minimum rail width dimension is between about 20.0% and about
50.0%. In other implementations the percentage change between the
maximum rail width dimension and the minimum rail width dimension
is between about 25.0% and about 45.0%. In other implementations
the percentage change between the maximum rail width dimension and
the minimum rail width dimension is between about 35.0% and about
45.0%. In an exemplary implementation the width dimension of the
rail segments transitions from a maximum width dimension of about
0.0047.+-.0.0004 inches to a minimum width dimension of about
0.0027.+-.0.0004 inches. In another exemplary implementation the
width dimension of the rail segments transitions from a maximum
width dimension of about 0.0047.+-.0.0004 inches to a minimum width
dimension of about 0.0035.+-.0.0004 inches. In another exemplary
implementation the width dimension of the rail segments transitions
from a maximum width dimension of about 0.0047.+-.0.0004 inches to
a minimum width dimension of about 0.0037.+-.0.0004 inches. As
discussed above, post-polishing of the devices generally involve an
etching process that typically results in a 40% to 50% reduction in
the as-cut cross-sectional dimensions.
[0163] Although FIG. 30 represents rail segments devoid of
undulations, as previously described herein, it is appreciated that
rail segments such as those shown in FIGS. 1A and 4A are also
contemplated. Moreover, it is appreciated that other than the rail
width characteristics disclosed above, any number of the features
and/or characteristics of the vascular treatment devices previously
disclosed herein with respect to FIGS. 1 through 29 (e.g.,
dimensional, spatial, relational, etc.) may be incorporated into a
clot retrieval device 6000 according to FIG. 30.
[0164] In some implementations the width of rails 6001 and 6002
taper along their length (or a portion thereof) in a substantial
uniform and diminishing fashion. In some implementations discrete
portions of the rails have a substantially uniform width dimension
with transitional tapers being used to join rail portions of
different widths. In some implementations discrete portions of the
rails have a substantially uniform width dimension with stepped
transitions between rail portions of different widths. In other
implementations two or more of the preceding width transitional
methods are utilized. Although not required, it is preferable that
the width transitions occur at portions along the rail struts other
than at a junction of the struts (e.g., junctions 6030).
[0165] In some implementations, as previously described, struts
6012 and 6013 of the most proximal cell structure 6018 also have an
enhanced width dimension that may be equal to or less than the
maximum rail width dimension for the purpose of enhancing the
pushability of the clot retrieval device as it is advanced through
the tortuous anatomy of a patient. In some implementations less
than the entire length of struts 6012 and 6013 are provided with an
enhanced width dimension. For example, in some implementations an
enhanced width portion extends from a proximal most end of struts
6012 and 6013 and terminates a distance prior to juncture 6026. The
configuration of struts 6012 and 6013 may also be altered in
manners previously disclosed.
[0166] With continued reference to FIG. 30, in exemplary
implementations all or portions of struts 6003 and 6004 (and
optionally all or the proximal portions of struts 6005 and 6006)
have width dimensions between about 0.0045 inches and about 0.0050
inches, all or portions of struts 6007 and 6008 (and optionally all
or the distal portions of struts 6005 and 6006) have width
dimensions between about 0.0035 inches and about 0.0036 inches, all
or portions of struts 6009 and 6010 (and optionally all or the
distal portions of struts 6007 and 6008) have width dimensions
between about 0.0027 inches and about 0.0035 inches, and with a
substantial portion of the strut elements in the remaining portions
of the device (portions A, B and C) having width dimensions between
about 0.0027 inches and about 0.0034 inches. In one or more of the
immediately preceding implementations, the width dimension of
struts 6012 and 6013 is between about 0.0033 inches and about
0.0047 inches, and preferably between about 0.0033 inches and about
0.0040 inches. It is to be appreciated that the dimensions
disclosed throughout this disclosure relate to exemplary
implementations and are also subject to customary manufacturing
tolerances. Variations in the dimensions are possible and
contemplated.
[0167] Although not required, it is preferable that the width
transitions occur at portions along the struts themselves other
than at a junction of the struts (e.g., junctions 6030 and
6032).
[0168] In one exemplary implementation struts 6003-6006 have a
width dimension of about 0.0047 inches, struts 6007, 6008 and a
proximal portion of strut 6010 have a width dimension of about
0.0036 inches, struts 6009, 6011 and a distal portion of strut 6010
have a width dimension of about 0.0035 inches, struts 6012-6013
have a width dimension of about 0.0036 inches, with all or a
substantial portion of the remaining strut elements of the
treatment device having a width dimension of about 0.0027
inches.
[0169] Testing has shown the proximal taper region of the treatment
devices of FIG. 30 to possess good force transmission
characteristics along with good radial force characteristics that
provide good sheathing and re-sheathing of the proximal taper
portion into an introducer sheath and/or delivery catheter.
[0170] In another exemplary implementation struts 6003-6006 have a
width dimension of about 0.0047 inches, struts 6007, 6008 and a
proximal portion of strut 6010 have a width dimension of about
0.0036 inches, struts 6009, 6011 and a distal portion of strut 6010
have a width dimension of about 0.0035 inches, struts 6012-6013
have a width dimension of about 0.0036 inches, the remaining strut
elements in section A of the clot retrieval device having a width
dimension of about 0.0033 inches and the remaining strut elements
generally located in sections B and C of the clot retrieval device
having a width dimension of about 0.0027 inches. The increased
width dimension of the struts in section A advantageously reduces
the likelihood of struts buckling within the proximal taper region
of the clot retrieval device and also increases the radial strength
of the proximal taper region.
[0171] In another exemplary implementation struts 6003-6006 have a
width dimension of about 0.0047 inches, struts 6007, 6008 and a
proximal portion of strut 6010 have a width dimension of about
0.0036 inches, struts 6009, 6011 and a distal portion of strut 6010
have a width dimension of about 0.0035 inches, the remaining strut
elements in section D of the treatment device having a width
dimension of about 0.0033 inches and the remaining strut elements
of sections B and C of the treatment device having a width
dimension of about 0.0027 inches. The increased width dimension of
the struts in section A advantageously reduces the likelihood of
struts buckling within the proximal taper region of the clot
retrieval device during its delivery to a treatment site of a
patient and also increases the radial strength of the proximal
taper region.
[0172] In another exemplary implementation struts 6003-6006 have a
width dimension of about 0.0047 inches, struts 6007, 6008 and a
proximal portion of strut 6010 have a width dimension of about
0.0036 inches, struts 6009, 6011 and a distal portion of strut 6010
have a width dimension of about 0.0035 inches, struts 6012-6013
have a width dimension of about 0.0036 inches, the strut elements
generally located in section C of the clot retrieval device having
a width dimension of about 0.0033 inches, and the remaining strut
elements of sections A and B of the clot retrieval device having a
width dimension of about 0.0027 inches. The increased width
dimension of the struts in section C advantageously reduces the
likelihood of struts buckling within the distal taper region of the
clot retrieval device during its delivery to a treatment site of a
patient. The increased width dimension also increases the radial
strength of the proximal taper region that enhances the ability of
the distal taper region to remain open while the clot retrieval
device is withdrawn from a patient. This feature is particularly
advantageous when the clot retrieval device is used for clot
removal in that it enables the distal taper section to remain open
and sweep away remaining portions of the clot when the clot
retrieval device is being withdrawn from the patient.
[0173] According to some implementations the clot retrieval devices
6000 according to FIG. 30 are laser cut from a tube having an inner
diameter of about 2.667 millimeters and a wall thickness of between
about 0.102 millimeters to about 0.126 millimeters. In use, a clot
retrieval device 6000 according to an implementation of that shown
in FIG. 30 is advanced through the tortuous vascular anatomy or
bodily duct of a patient to a treatment site in an unexpanded or
compressed state of a first nominal diameter and is movable from
the unexpanded state to a radially expanded state of a second
nominal diameter greater than the first nominal diameter for
deployment at the treatment site. In alternative exemplary
embodiments the second nominal diameter (e.g., average diameter of
main body portion) is about 4.0.+-.0.5 millimeters. In some
implementation, the dimensional and material characteristics of the
cell structures 6020 generally residing in the main body (section
B) of the expandable material are selected to produce sufficient
radial force and contact interaction to cause the cell structures
6020 to engage with an embolic obstruction/clot residing in the
vascular in a manner that permits partial or full removal of the
embolic obstruction from the patient.
[0174] In some implementations the dimensional and material
characteristics of the elements along the expandable length of the
retrieval device are selected to produce a radial force per unit
length of between about 0.030 N/mm to about 0.055 N/mm when the
outer diameter of the retrieval device is restrained to 1.5
millimeters. In some implementations the dimensional and material
characteristics of the elements along the expandable length are
selected to produce a radial force per unit length of between about
0.035 N/mm to about 0.050 N/mm when the outer diameter of the
retrieval device is restrained to 1.5 millimeters. In some
implementations the dimensional and material characteristics of the
elements along the expandable length are selected to produce a
radial force per unit length of between about 0.037 N/mm to about
0.049 N/mm when the outer diameter of the retrieval device is
restrained to 1.5 millimeters. Among the same or alternative
implementations, the dimensional and material characteristics of
the elements along the expandable length of the retrieval device
are selected to produce a radial force of between about 0.010 N/mm
to about 0.020 N/mm when the nominal diameter of the main body
portion is about 3.0.+-.0.5 millimeters.
[0175] In the implementations of FIG. 30, many of the cell
structures (excluding those that are formed at least in part by
rail segments 6001 and 6002) are shown having similar shapes with
most of the cell structure including a pair of short struts 6022
and a pair of long struts 6023. According to some implementations
the area of the cells are about 4.00.+-.0.5 mm.sup.2. In an
exemplary implementation the cell areas are about 4.2 mm.sup.2. In
exemplary implementations, short struts 6022 have a length of
between about 0.080 and about 0.100 inches, long struts 6023 have a
length of between about 0.130 and about 0.140 inches to produce a
staggered cell arrangement about the circumference of the treatment
device. In some implementations the overall length of the
expandable portion of the clot retrieval device is between about
35.0 to about 45.0 millimeters with the main body portion (section
B) having a length of about 20.0 to about 25.0 millimeters. In one
exemplary embodiment the overall length of the expandable portion
of the clot retrieval device is about 42.7 millimeters with the
main body portion (section B) having a length of about 21.7
millimeters and the proximal and distal taper regions having a
length of about 12.4 millimeters and about 8.6 millimeters,
respectively.
[0176] FIG. 31 illustrates clot retrieval devices 6050 according to
other implementations where, among other features, the strut
elements of rail segments 6051 and 6052 have varying width
dimensions. Clot retrieval device 6050 is particularly adapted for
the treatment of small diameter vessels/duct. In one
implementation, as shown in FIG. 31, the circumference of the main
body portion (section A) comprises three cell structures 6080, but
is not limited to such a construction. FIG. 31 depicts the clot
retrieval treatment device 6050 in a two-dimensional plane view as
if the device were cut and laid flat on a surface. FIG. 31 depicts
the device in its manufactured (as-cut) configuration. In one
implementation, rail segment 6051 transitions from a maximum width
dimension at or near its proximal end 6053 to a minimum width
dimension at or near its distal end 6054. In a like manner, rail
segment 6052 transitions from a maximum width dimension at or near
its proximal end 6053 to a minimum width dimension at or near its
distal end 6055. As previously discussed, the width dimensions of
the rail segments are selected to enhance their ability to
distribute forces and to resist buckling when a push force is
applied to the proximal end 6053 of the vascular treatment device.
In some implementations the percentage change between the maximum
rail width dimension and the minimum rail width dimension is
between about 20.0% and about 30.0%, and preferably between about
20% and about 25%. In an exemplary implementation the width
dimension of the rail segments transitions from a maximum width
dimension of about 0.0047.+-.0.0004 inches to a minimum width
dimension of about 0.0036.+-.0.0004 inches.
[0177] Although FIG. 31 represents rail segments 6051 and 6052 that
are devoid of undulations, as previously described herein, it is
appreciated that rail segments such as those shown in FIGS. 1A and
4A are also contemplated. Moreover, it is appreciated that other
than the rail width characteristics disclosed above, any number of
the features and/or characteristics of the treatment devices
previously described herein with respect to FIGS. 1 through 29
(e.g., dimensional, spatial, relational, etc.) may be incorporated
into a clot retrieval device 6050 according to FIG. 31.
[0178] In some implementations the width of rail 6051 and 6052
taper along their length (or a portion thereof) in a substantial
uniform and diminishing fashion. In some implementations discrete
portions of the rails have a substantially uniform width dimension
with only transitional tapers being used to join rail portions of
different widths. In some implementations discrete portions of the
rails have a substantially uniform width dimension with stepped
transitions between rail portions of different widths. In other
implementations two or more of the preceding width transitional
methods are utilized. Although not required, it is preferable that
the width transitions occur at portions along the rail struts other
than strut junctions (e.g., junctions 6064).
[0179] In some implementations struts 6056 and 6057 of the most
proximal cell structure also have enhanced width dimensions that
may be equal to or less than the maximum rail width dimension for
the purpose of enhancing the pushability of the clot retrieval
device as it is advanced through the tortuous anatomy of a patient.
In some implementations less than the entire length of struts 6056
and 6057 are provided with an enhanced width dimension. For
example, in some implementations an enhanced width portion extends
from a proximal most end of struts 6056 and 6057 and terminates a
distance prior to juncture 6058. Moreover, the configuration of
struts 6056 and 6057 may also be altered in manners previously
disclosed.
[0180] With continued reference to FIG. 31, in exemplary
implementations rail portions 6060 and 6061 have width dimensions
of about 0.0047 and rail portions 6062 and 6063 have width
dimensions of about 0.0036 inches, with a substantial portion of
the strut elements in the remaining portions of the device 6050
having a width dimension of about 0.0027 inches. In other exemplary
implementations rail portions 6060 and 6061 have width dimensions
of about 0.0047 and rail portions 6062 and 6063 have width
dimensions of about 0.0036 inches, with the struts in a distal
portion 6070 of device (illustrated with dashed lines) having a
width dimension of about 0.0023 inches and a majority of the
remaining struts having a width dimension of about 0.0027 inches.
The reduced width dimension of distal portion 6070 produces a
region of lower radial strength that in smaller vessels or ducts
minimizes surface interactions between the distal portion 6070 and
the vessel/duct to prevent or minimize the occurrence of damage to
the vessel/duct wall while the clot retrieval device is proximally
withdrawn from a patient.
[0181] Testing has shown the proximal taper region of the clot
retrieval devices 6050 to possess good force transmission
characteristics along with good radial force characteristics that
provide good sheathing and re-sheathing of the proximal taper
portion into an introducer sheath and/or delivery catheter.
[0182] According to some implementations the clot retrieval devices
6050 according to FIG. 31 are laser cut from a tube having an inner
diameter of about 2.130 millimeters and a wall thickness of between
about 0.104 millimeters to about 0.128 millimeters. In use, a clot
retrieval device 6050 according to an implementation of that shown
in FIG. 31 is advanced through the tortuous vascular anatomy or
bodily duct of a patient to a treatment site in an unexpanded or
compressed state of a first nominal diameter and is movable from
the unexpanded state to a radially expanded state of a second
nominal diameter greater than the first nominal diameter for
deployment at the treatment site. In alternative exemplary
embodiments the second nominal diameter (e.g., average diameter of
main body portion) is about 3.0.+-.0.5 millimeters. In some
implementation, the dimensional and material characteristics of the
cell structures 6080 residing in the main body portion (section A)
are selected to produce sufficient radial force and contact
interaction to cause the cell structures 6080 to engage with an
embolic obstruction residing in the vascular in a manner that
permits partial or full removal of the embolic obstruction from the
patient.
[0183] In some implementations the dimensional and material
characteristics of the elements along the expandable length of the
retrieval device are selected to produce a radial force per unit
length of between about 0.015 N/mm to about 0.035 N/mm when the
outer diameter of the retrieval device is restrained to 1.5
millimeters. In some implementations the dimensional and material
characteristics of the elements along the expandable length are
selected to produce a radial force per unit length of between about
0.017 N/mm to about 0.033 N/mm when the outer diameter of the
retrieval device is restrained to 1.5 millimeters. Among the same
or alternative implementations, the dimensional and material
characteristics of the elements along the expandable length of the
retrieval device are selected to produce a radial force of between
about 0.010 N/mm to about 0.020 N/mm when the nominal diameter of
the main body portion is about 2.0.+-.0.5 millimeters.
[0184] In the implementations of FIG. 31, many of the cell
structures (excluding those that are formed at least in part by
rail segments 6051 and 6052) are shown having similar shapes with
most of the cell structure including a pair of short struts 6081
and a pair of long struts 6082 that are joined by connector regions
6083. In exemplary implementations (as shown in FIGS. 32A-C), short
struts 6081 have a linear length, L.sub.1, of about 0.055.+-.0.010
inches, long struts 6082 have a linear length, L.sub.3, of about
0.128.+-.0.010 inches and connector regions 6083 have a linear
length, L.sub.3, of about 0.0371.+-.0.010 inches. In one or more
implementations the cell structures 6080 have an area of about 4.5
mm.sup.2 to about 5.5 mm.sup.2. In one exemplary implementation the
cell structures 6080 have an area of about 5.0 mm.sup.2. In
exemplary implementations the overall length of the expandable
portion of the clot retrieval device is between about 25.0
millimeters and about 35.0 millimeters with the main body portion
(section A) having a length of between about 10.0 millimeters and
about 15.0 millimeters. In one exemplary implementation the overall
length of the expandable portion of the clot retrieval device is
about 30.7 millimeters with the main body portion (section A)
having a length of about 13.1 millimeters and the proximal and
distal taper regions having a length of about 10.9 millimeters and
about 6.7 millimeters, respectively.
[0185] Turning now to FIG. 33A, an alternative implementation to
the clot retrieval devices described above in conjunction with FIG.
30 is depicted. FIGS. 33B and 33C illustrate exemplary
three-dimensional top and side views of the clot retrieval devices
7000 of FIG. 33A. Sections of the treatment device 7000 that are
generally identified as regions E and G are in many respects
similar, and in some instances the same, to the same general
regions of the clot retrieval devices 6000 described above. As an
example, the width dimension of the struts generally located in
region G may in different implementations take different values to
establish any of a variety of desired distal taper characteristics
as disclosed above. In addition, region E may assume any of a
variety of implementations as previously disclosed above in
conjunction with the retrieval devices of FIG. 30. As shown in FIG.
33A, the sizes of the cell structures 7002 generally located in a
central region F of the device 7000 are larger than those in the
implementations of devices 6000 described above. An advantage of
the decreased strut density in the central region F of device 7000
is that it enhances the integration of an embolic obstruction/clot
within region F of the device. In the treatment devices 7000 of
FIGS. 33, the larger cell structures are created by the omission of
selected long struts 6022 in the device 6000 of FIG. 30 to create
cell structures 7002 having areas that are about double the size of
cells 7024. In one implementation, cell structures 7020 have an
area of between about 8.0 mm.sup.2 and about 8.5 mm.sup.2. In one
exemplary implementation cell structures 7020 have an area of about
8.3 mm.sup.2. It is important to note that any of a number of other
methods may be used to create the larger cell structures. A
particular advantage of the implementations of FIGS. 33 is that
good strut nesting characteristics are preserved to facilitate a
low profile delivery state of the device 7000.
[0186] A decrease in the strut density in a region generally
results in a lower radial strength within the region. In a clot
retrieval device this reduction can adversely affect the device's
ability to integrate with an embolic obstruction/clot. To
compensate for this reduction in radial strength, in some
implementations selective strut portions 7006 (denoted by dashed
lines) generally located within region F of the retrieval devices
are provided with a width dimension greater than the width
dimension of strut portions 7004 (denoted by solid lines). In
accordance with some implementations the width dimensions of strut
portions 7006 are selected so that the over-all radial strength per
unit length of expandable portion of the retrieval device is
similar to that absent the removal of struts to create the larger
sized cell structures. As an example, in the implementations
described above where decreased strut density is achieved by the
omission of certain long struts 6022 in a device of FIG. 30, the
width of struts 7006 are selected so that the over-all radial
strength per unit length of the expandable portion of the retrieval
device is similar to that of devices 6000 described above. For
example, in some implementations strut portions 7004 have a width
dimension of about 0.0027 inches with strut portions 7006 having a
width dimension of about 0.0035 inches so that the over-all radial
strength per unit length of the expandable portion is similar to
the same area of the retrieval devices 6000 having mostly unitary
cell sizes and strut width dimensions of about 0.0027 inches.
[0187] Although not required, as illustrated in FIG. 33A, the
transition of strut widths preferably occur at locations (denoted
by "x") other than junctions 7008. Although not required, the width
transitions preferably comprise tapers that provide a relatively
smooth transition between the different width dimensions.
[0188] Strut portions of enhanced width 7006 are one method of
creating a desired over-all radial strength per unit length. Other
methods are also available. For example, strut portions 7006 may
instead have an enhanced thickness dimension over strut portions
7004, or may have a combination of enhanced thickness and width
dimensions. In other implementations the width dimension of a
majority, substantially all or all of the struts generally located
in section F are enhanced to compensate for the reduction in strut
density.
[0189] With reference to FIG. 34A, alternative implementations to
the clot retrieval devices described above in conjunction with FIG.
30 are depicted. FIGS. 34B and 34C illustrate exemplary
three-dimensional top and side views of the clot retrieval devices
7020 of FIG. 34A. Sections of the treatment device 7020 that are
generally identified as regions E and G are in many respects
similar, and in some instances the same, to the same general
regions of the clot retrieval devices 6000 described above. As an
example, the width dimension of the struts in region G may, in
different implementations, take different values to establish any
of a variety of desired distal taper characteristics as disclosed
above. In addition, region E may assume any of a variety of
implementations as previously disclosed above in conjunction with
the retrieval devices of FIG. 30. As shown in FIG. 34A, the sizes
of some of the cell structures 7022 in a central region J of the
device 7020 are larger than those in the implementations of devices
6000 described above to provide circumferentially extending zones
of decreased strut density that are generally separated by
circumferentially extending rows of non-enlarged cell structures
7024. In the treatment devices 7020 of FIGS. 34, the larger cell
structures are created by the omission of selected long struts 6022
in the device 6000 of FIG. 30 to create cell structures 7022 having
areas of about double in size. In one implementation cell
structures 7022 have an area of about 8.3 mm.sup.2. It is important
to note that any of a number of other methods may be used to create
the larger cell structures. A particular advantage of the
implementations of FIGS. 34 is that good strut nesting
characteristics are preserved to facilitate a low profile delivery
state of the device 7020.
[0190] As discussed above, a decrease in the strut density in a
region generally results in a lower radial strength within the
region. In a clot retrieval device this reduction can adversely
affect the device's ability to integrate with an embolic
obstruction/clot. To compensate for this reduction in radial
strength, selective strut portions 7026 (denoted by dashed lines)
generally located within region J of the retrieval devices are
provided with a width dimension greater than the width dimension of
strut portions 7025 (denoted by solid lines). In accordance with
some implementations the width dimensions of strut portions 7026
are selected so that the over-all radial strength per unit length
of the expandable portion of the retrieval device is similar to
that absent the removal of struts to create the larger sized cell
structures. As an example, in the implementations described above
where decreased strut density is achieved by the omission of
certain long struts 6022 in a device of FIG. 30, the width of
struts 7026 are selected so that the over-all radial strength per
unit length of the expandable portion of the retrieval device is
similar to that of devices 6000 described above. For example, in
some implementations strut portions 7025 have a width dimension of
about 0.0027 inches with strut portions 7026 having a width
dimension of about 0.0035 inches so that the over-all radial
strength per unit length of the expandable portion of the retrieval
device is similar to the same area of the retrieval devices 6000
having mostly unitary cell sizes and strut width dimensions of
about 0.0027 inches. In some implementation the width of the struts
7029 have a width dimension of between 0.0031 inches and about
0.0033 inches similar to those previously discussed above with
respect to some implementations of device 6000.
[0191] In some implementations, as illustrated in FIG. 34A, the
transition of some or all of the strut widths occur at locations
other than junctions 7028, while in other implementations the
transition of some or all of the strut widths occur at locations
other than junctions 7028. Although not required, the width
transitions preferably comprise tapers that provide a relatively
smooth transition between the different width dimensions.
[0192] Strut portions of enhanced width 7026 are one method of
creating in region J a desired over-all radial strength. Other
methods are also available. For example, strut portions 7026 may
instead have an enhanced thickness dimension over strut portions
7025, or may have a combination of enhanced thickness and width
dimensions.
[0193] With reference to FIG. 35A, an alternative implementation to
the clot retrieval devices described above in conjunction with FIG.
30 is depicted. FIGS. 35B and 35C illustrate exemplary
three-dimensional top and side views of the clot retrieval devices
7050 of FIG. 35A. Sections of the treatment device 7050 that are
generally identified as regions E and G are in many respects
similar, and in some instances the same, to the same general
regions of the clot retrieval devices 6000 described above. As an
example, the width dimension of the struts generally located in
region G may in different implementations take different values to
establish any of a variety of desired distal taper characteristics
as disclosed above. In addition, region E may assume any of a
variety of implementations as previously disclosed above in
conjunction with the retrieval devices of FIG. 30. As shown in FIG.
35A, the sizes of some of the cell structures 7052 in a central
region K of the device 7050 are larger than those in the
implementations of devices 6000 described above to provide zones of
decreased strut density that are dispersed among non-enlarged cell
structures 7054. In the treatment devices 7050 of FIGS. 35, the
larger cell structures are created by the omission of selected long
struts 6022 in the device 6000 of FIG. 30 to create cell structures
7052 having areas of about double the size of cells 7054. In one
implementation the area of cell structures 7052 is about 8.3
mm.sup.2. It is important to note that any of a number of other
methods may be used to create the larger cell structures. A
particular advantage of the implementations of FIGS. 35 is that
good strut nesting characteristics are preserved to facilitate a
low profile delivery state of the device 7050.
[0194] As discussed above, a decrease in the strut density in a
region generally results in a lower radial strength within the
region. In a clot retrieval device this reduction can adversely
affect the device's ability to integrate with an embolic
obstruction/clot. To compensate for this reduction in radial
strength, selective strut portions 7056 (denoted by dashed lines)
generally located within region K of the retrieval devices are
provided with a width dimension greater than the width dimension of
strut portions 7055 (denoted by solid lines). In accordance with
some implementations the width dimensions of strut portions 7056
are selected so that the over-all radial strength per unit length
of the expandable portion of the retrieval device is similar to
that absent the removal of struts to create the larger sized cell
structures. As an example, in the implementations described above
where decreased strut density is achieved by the omission of
certain long struts 6022 in a device of
[0195] FIG. 30, the width of struts 7056 are selected so that the
over-all radial strength per unit length of the expandable portion
of the retrieval device is similar to that of devices 6000
described above. For example, in some implementations strut
portions 7055 have a width dimension of about 0.0027 inches with
strut portions 7056 having a width dimension of about 0.0035 inches
so that the over-all radial strength per unit length of the
expandable portion of the retrieval device is similar to the same
area of the retrieval devices 6000 having mostly unitary cell sizes
and strut width dimensions of about 0.0027 inches. In some
implementations the width of the struts 7059 have a width dimension
of between 0.0031 inches and about 0.0033 inches similar to those
previously discussed above with respect to some implementations of
device 6000.
[0196] Although not required, as illustrated in FIG. 35A, the
transition of strut widths preferably occur at locations other than
junctions 7058. Although not required, the width transitions
preferably comprise tapers that provide a relatively smooth
transition between the different width dimensions.
[0197] Strut portions of enhanced width 7056 are one method of
creating a desired over-all radial strength per unit length. Other
methods are also available. For example, strut portions 7056 may
instead have an enhanced thickness dimension over strut portions
7055, or may have a combination of enhanced thickness and width
dimensions.
[0198] FIG. 36 illustrates clot retrieval devices 6090 similar to
those of FIG. 30, with a difference in the size of the cell
structures 6091 generally located in region B of the device. As
illustrated in FIG. 36, cell structures 6091 are of a greater size
than the cell structures 6020 of the device shown in FIG. 30. As
previously discussed, an advantage of larger sized cell structures
within the main body portion of the retrieval device is that it
enhances clot integration into the main body portion when a radial
strength of the main body portion is properly provided. For the
purpose of providing sufficient radial strength in region B of the
device 6090, the struts 6092 (denoted by dashed lines) generally
located within region B have an enhanced width dimension, which in
one implementation is about 0.0035 inches. In one implementation
the width dimension of the struts 6092 generally located in region
B are similar to or the same as the width dimension of the distal
sections of rail segments 6001 and/or 6002 (e.g., having the same
or similar width dimension of one or more of struts 6009, 6010 and
6011). Although not required, the transition in width dimensions
preferably occur at locations other than at junctions 6045, as
illustrated in FIG. 36.
[0199] FIG. 37 illustrates clot retrieval devices 8000 according to
other implementations where, among other features, the strut
elements of rail segments 8001 and 8002 have varying width
dimensions. FIG. 37 depicts a clot retrieval device in a
two-dimensional plane view as if the device were cut and laid flat
on a surface. FIG. 37 depicts the device in its manufactured
(as-cut) configuration. In one implementation, rail segment 8001
transitions from a maximum width dimension at or near its proximal
end 8014 to a minimum width dimension at or near its distal end
8015. In a like manner, rail segment 8002 transitions from a
maximum width dimension at or near its proximal end 8014 to a
minimum width dimension at or near its distal end 8016. As
previously discussed, the width dimensions of the rail segments are
selected to enhance their ability to distribute forces and to
resist buckling when a push force is applied to the proximal end
8014 of the clot retrieval device. In some implementations the
percentage change between the maximum rail width dimension and the
minimum rail width dimension is between about 20.0% and about
35.0%. In other implementations the percentage change between the
maximum rail width dimension and the minimum rail width dimension
is between about 25.0% and about 30.0%. In an exemplary
implementation the width dimension of the rail segments transitions
from a maximum width dimension of about 0.0047.+-.0.0004 inches to
a minimum width dimension of about 0.0027.+-.0.0004 inches. In
another exemplary implementation the width dimension of the rail
segments transitions from a maximum width dimension of about
0.0047.+-.0.0004 inches to a minimum width dimension of about
0.0034.+-.0.0004 inches.
[0200] Although FIG. 37 represents rail segments that are devoid of
undulations, as previously described herein, it is appreciated that
rail segments such as those shown in FIGS. 1A and 4A are also
contemplated. Like the devices of FIG. 30 disclosed above, it is
appreciated that other than the rail width characteristics
disclosed in the preceding paragraph, any of a number of the
features and/or characteristics of the vascular treatment devices
described in conjunction with the devices of FIGS. 1-29 (e.g.,
dimensional, spatial, relational, etc.) may be incorporated into a
clot retrieval device 8000 according to FIG. 37.
[0201] In some implementations the width of rails 8001 and 8002
taper along their length (or a portion thereof) in a substantial
uniform and diminishing fashion. In some implementations discrete
portions of the rails have a substantially uniform width dimension
with only transitional tapers being used to join rail portions of
different widths. In some implementations discrete portions of the
rails have a substantially uniform width dimension with stepped
transitions between rail portions of different widths. In other
implementations two or more of the preceding width transitional
methods are utilized. Although not required, it is preferable that
the width transitions occur at portions along the rail struts other
than at a junction of the struts (e.g., junctions 8030).
[0202] In some implementations, as previously described, struts
8012 and 8013 of the most proximal cell structure 8018 also have an
enhanced width dimension that may be equal to or less than the
maximum rail width dimension for the purpose of enhancing the
pushability of the clot retrieval device as it is advanced through
the tortuous anatomy of a patient. In some implementations less
than the entire length of struts 8012 and 8013 are provided with an
enhanced width dimension. For example, in some implementations an
enhanced width portion extends from a proximal most end of struts
8012 and 8013 and terminates a distance prior to their juncture.
The configuration of struts 8012 and 8013 may also be altered in
manners previously disclosed.
[0203] With continued reference to FIG. 37, in exemplary
implementations all or portions of struts 8003 and 8004 (and
optionally all or portions of struts 8005 and 8006) have width
dimensions of about 0.0045 inches to about 0.0050 inches, all or
portions of struts 8007 and 8008 (and optionally all or portions of
struts 8005 and 8006) have width dimensions of about 0.0036 inches
to about 0.0040 inches, all or portions of struts 8009 and 8010
(and optionally all or portions of struts 8007 and 8008) have width
dimensions of about 0.0034 inches to about 0.0036 inches. In some
implementations the remainder of the struts generally located in
region M of the device have width dimensions of about 0.0027
inches, the struts in region N have width dimensions of about
0.0034 inches to about 0.0036 inches, and the struts generally
located in region O have a width dimension of about 0.0031 inches
to about 0.033 inches. In one or more of the immediately preceding
implementations, the width dimension of struts 8012 and 8013 is
between about 0.0036 inches and about 0.0047 inches. It is to be
appreciated that the dimensions disclosed relate to exemplary
implementations and are also subject to customary manufacturing
tolerances. Variations in the dimensions are also possible and
contemplated.
[0204] Although not required, it is preferable that the width
transitions occur at portions along the struts themselves other
than at a junction of the struts (e.g., junctions 8030 and
8032).
[0205] As illustrated in FIG. 37, the strut density in the region
generally identified by "N" is notably less than the strut
densities in the regions generally identified by "M" and "O". As a
consequence, the cell structures 8020 generally located in region N
are of a larger size than the cell structures 8021 generally
located in regions N and O. As previously discussed, an advantage
of larger sized cell structures within the main body portion of the
retrieval device is that it enhances clot integration into the main
body portion (region N) when a radial strength of the main body
portion is properly provided. For the purpose of providing
sufficient radial strength in region N of the device, the struts
within region have an enhanced width dimension as compared to the
cell struts generally residing in region M (other than the struts
8003-8013) and the cell struts generally residing in region O. In
one implementation the width dimension of the struts in region N
are similar to or the same as the width dimension of the distal
struts 8009, 8010 and/or 8011 of rail segments 8001 and/or
8002.
[0206] In an exemplary implementation struts 8003-8006 have a width
dimension of about 0.0047 inches, struts 8007, 8008, and a proximal
portion of strut 8010 have a width dimension of about 0.0040
inches, struts 8009, 8011 and a distal portion of strut 8010 have a
width dimension of about 0.0034 inches, struts 8012-8013 have a
width dimension of about 0.0040 inches. In some implementations the
remainder of the struts in region M of the device have width
dimensions of about 0.0027 inches, the struts in region N have
width dimensions of about 0.0034 inches, and the struts in region O
have a width dimension of about 0.0031 inches. The increased width
dimension of the struts in section O advantageously reduces the
likelihood of struts buckling within the distal taper region of the
clot retrieval device during its delivery to a treatment site of a
patient. The increased width dimension also increases the radial
strength of the distal taper region that enhances the ability of
the distal taper region to remain open while the clot retrieval
device is withdrawn from a patient so that it may sweep away
remaining portions of the clot when the clot retrieval device is
being withdrawn from the patient.
[0207] According to some implementations the clot retrieval devices
8000 according to FIG. 37 are laser cut from a tube having an inner
diameter of about 3.77 millimeters and a wall thickness of between
about 0.097 millimeters to about 0.131 millimeters. In use, a clot
retrieval device 8000 according to an implementation of that shown
in FIG. 37 is advanced through the tortuous vascular anatomy or
bodily duct of a patient to a treatment site in an unexpanded or
compressed state of a first nominal diameter and is movable from
the unexpanded state to a radially expanded state of a second
nominal diameter greater than the first nominal diameter for
deployment at the treatment site. In alternative exemplary
embodiments the second nominal diameter (e.g., average diameter of
main body portion) is about 5.5.+-.0.5 millimeters. In some
implementation, the dimensional and material characteristics of the
cell structures 8020 residing in the main body (section N) are
selected to produce sufficient radial force and contact interaction
to cause the cell structures 8020 to engage with an embolic
obstruction/clot residing in the vascular in a manner that permits
partial or full removal of the embolic obstruction from the
patient.
[0208] In some implementations the dimensional and material
characteristics of the elements along the expandable length of the
retrieval device are selected to produce a radial force per unit
length of between about 0.040 N/mm to about 0.065 N/mm when the
outer diameter of the retrieval device is restrained to 1.5
millimeters. In some implementations the dimensional and material
characteristics of the elements along the expandable length are
selected to produce a radial force per unit length of between about
0.045 N/mm to about 0.060 N/mm when the outer diameter of the
retrieval device is restrained to 1.5 millimeters. In some
implementations the dimensional and material characteristics of the
elements along the expandable length are selected to produce a
radial force per unit length of between about 0.050 N/mm to about
0.060 N/mm when the outer diameter of the retrieval device is
restrained to 1.5 millimeters. In some implementations the
dimensional and material characteristics of the elements along the
expandable length are selected to produce a radial force per unit
length of between about 0.049 N/mm to about 0.057 N/mm when the
outer diameter of the retrieval device is restrained to 1.5
millimeters. Among the same or alternative implementations, the
dimensional and material characteristics of the elements along the
expandable length of the retrieval device are selected to produce a
radial force of between about 0.010 N/mm to about 0.020 N/mm when
the nominal diameter of the main body portion is about 4.5.+-.0.5
millimeters.
[0209] In the implementations of FIG. 37, the cell structures in
regions M and 0 (excluding those that are formed at least in part
by rail segments 8001 and 8002) are shown having similar shapes
with the cell structures 8021 including a pair of short struts 8022
and a pair of long struts 8024. In exemplary implementations the
area of cell structures 8021 is between about 4.5 mm.sup.2 and
about 5.5 mm.sup.2. In one exemplary implementation the area of
cell structures 8021 is about 5.0 mm.sup.2 to about 5.2 mm.sup.2.
The cell structures 8020 generally located in region N, in one
implementation, comprise a shape consisting of two adjoining cell
structures 8021 with a long strut 8024 being omitted between them.
Although other types of large sized cell structures are
contemplated, an advantage of the cell construction illustrated in
FIG. 37 is that it possesses good nesting capability to permit the
retrieval device to achieve a small delivery profile.
[0210] In some implementations the overall length of the expandable
portion of the clot retrieval device is between about 55.0
millimeters and about 65.0 millimeters with the main body portion
(section N) having a length of between about 25 millimeters and
about 35.0 millimeters and the proximal and distal taper regions
having a length of between about 10.0 to about 20.0 millimeters. In
one exemplary embodiment the overall length of the expandable
portion of the clot retrieval device is about 58.4 millimeters with
the main body portion (section N) having a length of about 29.3
millimeters and the proximal and distal taper regions having a
length of about 16.6 millimeters and 12.5 millimeters,
respectively.
[0211] FIG. 38 illustrates clot retrieval devices 8500 according to
other implementations where, among other features, the strut
elements of rail segments 8051 and 8052 have varying width
dimensions. FIG. 38 depicts a clot retrieval device in a
two-dimensional plane view as if the device were cut and laid flat
on a surface. FIG. 38 depicts the device in its manufactured
(as-cut) configuration. In one implementation, rail segment 8051
transitions from a maximum width dimension at or near its proximal
end 8066 to a minimum width dimension at or near its distal end
8067. In a like manner, rail segment 8052 transitions from a
maximum width dimension at or near its proximal end 8066 to a
minimum width dimension at or near its distal end 8068. As
previously discussed, the width dimensions of the rail segments are
selected to enhance their ability to distribute forces and to
resist buckling when a push force is applied to the proximal end
8064 of the clot retrieval device. In some implementations the
percentage change between the maximum rail width dimension and the
minimum rail width dimension is between about 20.0% and about
35.0%. In other implementations the percentage change between the
maximum rail width dimension and the minimum rail width dimension
is between about 22.0% and about 27.0%. In an exemplary
implementation the width dimension of the rail segments transitions
from a maximum width dimension of about 0.0047.+-.0.0004 inches to
a minimum width dimension of about 0.0035 .+-.0.0004 inches.
[0212] Although FIG. 38 represents rail segments that are devoid of
undulations, as previously described herein, it is appreciated that
rail segments such as those shown in FIGS. 1A and 4A are also
contemplated. Like the devices of FIG. 30 disclosed above, it is
appreciated that other than the rail width characteristics
disclosed in the preceding paragraph, any of a number of the
features and/or characteristics of the vascular treatment devices
described in conjunction with the devices of
[0213] FIGS. 1-29 (e.g., dimensional, spatial, relational, etc.)
may be incorporated into a clot retrieval device 8050 according to
FIG. 38.
[0214] In some implementations the width of rails 8051 and/or 8052
taper along their length (or a portion thereof) in a substantial
uniform and diminishing fashion. In some implementations discrete
portions of the rails have a substantially uniform width dimension
with only transitional tapers being used to join rail portions of
different widths. In some implementations discrete portions of the
rails have a substantially uniform width dimension with stepped
transitions between rail portions of different widths. In other
implementations two or more of the preceding width transitional
methods are utilized. Although not required, it is preferable that
the width transitions occur at portions along the rail struts other
than at a junction of the struts (e.g., junctions 8070).
[0215] In some implementations, in a manner previously described,
struts 8064 and 8065 of the most proximal cell structure also have
an enhanced width dimension that may be equal to or less than the
maximum rail width dimension for the purpose of enhancing the
pushability of the clot retrieval device as it is advanced through
the tortuous anatomy of a patient. In some implementations less
than the entire length of struts 8064 and 8065 are provided with an
enhanced width dimension. For example, in some implementations an
enhanced width portion extends from a proximal most end of struts
8064 and 8065 and terminates a distance prior to their juncture.
The configuration of struts 8064 and 8065 may also be altered in
manners previously disclosed.
[0216] With continued reference to FIG. 38, in exemplary
implementations all or portions of struts 8053 and 8054 (and
optionally all or portions of struts 8055 and 8056) have width
dimensions of about 0.0045 inches to about 0.0050 inches, all or
portions of struts 8057 and 8058 (and optionally all or portions of
struts 8055, 8056, 8059 and 8060) have width dimensions of about
0.0036 inches to about 0.0040 inches, all or portions of struts
8059 and 8060 (and optionally all or portions of struts 8061, 8062
and 8063) have width dimensions of about 0.0034 inches to about
0.0036 inches. In some implementations the remainder of the struts
generally located in region P of the device have width dimensions
of about 0.0027 inches, the struts generally located in region Q
have width dimensions of about 0.0034 inches to about 0.0036
inches, and the struts generally located in region R have a width
dimension of about 0.0031 inches to about 0.033 inches. In one or
more of the immediately preceding implementations, the width
dimension of struts 8064 and 8065 is between about 0.0036 inches
and about 0.0047 inches. It is to be appreciated that the
dimensions disclosed relate to exemplary implementations and are
also subject to customary manufacturing tolerances. Variations in
the dimensions are possible and contemplated.
[0217] Although not required, it is preferable that the width
transitions occur at portions along the struts themselves other
than at a junction of the struts (e.g., junctions 8070 and
8071).
[0218] As illustrated in FIG. 38, the strut density in the region
generally identified by "Q" is notably less than the strut
densities in the regions generally identified by "P" and "R". As a
consequence, the cell structures 8080 generally located in region Q
are of a larger size than the cell structures 8081 generally
located in regions P and R. As previously discussed, an advantage
of larger sized cell structures within the main body portion of the
retrieval device is that it enhances clot integration into the main
body portion (region Q) when a radial strength of the main body
portion is properly provided. For the purpose of providing
sufficient radial strength in region Q of the device, the struts
generally located within region Q have an enhanced width dimension
as compared to the cell struts generally located in region P (other
than the struts 8053-8065) and the cell struts generally located in
region R. In one implementation the width dimension of the struts
in region Q are similar to or the same as the width dimension of
the distal sections of rails 8051 and 8052 (e.g., struts 8061, 8062
and/or 8063).
[0219] In an exemplary implementation struts 8003-8006 and a
proximal portion of struts 8055 and 8056 have a width dimension of
about 0.0047 inches, struts 8057, 8058, and a distal and proximal
portions of struts 8055,8056 and 8059,8060, respectively, have a
width dimension of about 0.0040 inches, struts 8009, 8011 and a
distal portion of strut 8010 have a width dimension of about 0.0034
inches, struts 8012-8013 have a width dimension of about 0.0040
inches, struts 8061, 8062, 8063 and the distal portions of struts
8059 and 8060 have a width dimension of about 0.0035 inches. In
some implementations the remainder of the struts generally located
in region P of the device have width dimensions of about 0.0027
inches, the struts generally located in region Q have width
dimensions of about 0.0035 inches, and the struts generally located
in region R have a width dimension of about 0.0031 inches. The
increased width dimension of the struts in section R advantageously
reduces the likelihood of struts buckling within the distal taper
region of the clot retrieval device during its delivery to a
treatment site of a patient. The increased width dimension also
increases the radial strength of the distal taper region that
enhances the ability of the distal taper region to remain open
while the clot retrieval device is withdrawn from a patient so that
it may sweep away remaining portions of the clot when the clot
retrieval device is being withdrawn from the patient.
[0220] According to some implementations the clot retrieval devices
8050 according to FIG. 38 are laser cut from a tube having an inner
diameter of about 3.77 millimeters and a wall thickness of between
about 0.097 millimeters to about 0.131 millimeters. In use, a clot
retrieval device 8050 according to an implementation of that shown
in FIG. 38 is advanced through the tortuous vascular anatomy or
bodily duct of a patient to a treatment site in an unexpanded or
compressed state of a first nominal diameter and is movable from
the unexpanded state to a radially expanded state of a second
nominal diameter greater than the first nominal diameter for
deployment at the treatment site. In alternative exemplary
embodiments the second nominal diameter (e.g., average diameter of
main body portion) is about 6.0.+-.0.5 millimeters. In some
implementation, the dimensional and material characteristics of the
cell structures 8080 residing in the main body (section Q) are
selected to produce sufficient radial force and contact interaction
to cause the cell structures 8080 to engage with an embolic
obstruction/clot residing in the vascular in a manner that permits
partial or full removal of the embolic obstruction from the
patient. In some implementation, the dimensional and material
characteristics are selected to produce a radial force per unit
length in the expandable portion of the retrieval device of between
about 0.010 N/mm to about 0.020 N/mm when the diameter of the main
body portion is reduced to about 5.0 .+-.0.5 millimeters.
[0221] In the implementations of FIG. 38, the cell structures
generally located in regions P and R (excluding those that are
formed at least in part by rail segments 8051 and 8052) are shown
having similar shapes with the cell structures 8081 including a
pair of short struts 8082 and a pair of long struts 8084. In an
exemplary implementation the area of cell structures 8081 is about
9.2 mm.sup.2. The cell structures 8080 generally located in region
Q, in one implementation, comprise a shape consisting of two
adjoining cell structures 8081 with a long strut 8084 being omitted
between them. Although other types of large sized cell structures
are contemplated, an advantage of the cell construction illustrated
in FIG. 38 is that it possesses good nesting capability to permit
the retrieval device to achieve a small delivery profile.
[0222] In some implementations the overall length of the expandable
portion of the clot retrieval device is between about 65.0
millimeters and about 75.0 millimeters with the main body portion
(section Q) having a length of between about 25.0 millimeters and
about 35.0 millimeters. In one exemplary implementation the overall
length of the expandable portion of the clot retrieval device is
about 71.9 millimeters with the main body portion (section Q)
having a length of about 32.3 millimeters and the proximal and
distal taper regions having a length of about 22.5 millimeters and
17.1 millimeters, respectively.
[0223] FIG. 39 depicts a two dimensional view of a duct obstruction
retrieval device 370 according to another implementation. As with
some of the other implementations previously described, the
retrieval device 370 comprises a proximal tapered end portion 371,
a cylindrical main body portion 372 and a distal tapered end
portion 373. A difference in the distal tapered end portion 373 as
compared to the distal tapered end portions previously described is
that the distal tapered end portion 373 has less than three full
rows of cell structures so as to reduce the distal taper length. In
the example of FIG. 39 the distal tapered end portion comprises two
full rows of cell structures 374 and 375 and a partial row of cell
structures 376. (For the sake of clarity, although row 375 in the
implementation of FIG. 39 includes a single cell structure, it is
in any case considered a row of cell structures.) The inclusion of
a distal tapered end portion in the retrieval device that
culminates into a distal antenna provides a number of advantages
over retrieval devices that would otherwise terminate in a blunt
end. One advantage is that once the retrieval device has been
positioned and expanded in a vessel of a patient the tapered end
provides a greater degree of placement adjustment over a retrieval
device having a blunt end. Another advantage is that the distal
tapered end portion is more atraumatic than a blunt end. The
reduced taper length achieved by limiting the construction of the
distal tapered end portion 373 to less than three full rows of cell
structures has been found to advantageously result in a distal
taper that is both more stable and more atraumatic than those
having a greater number of full rows of cell structures. In
retrievers having cell structures of different sizes, like those of
cell structures 376 and 377, it is preferable that the full rows of
cells in the distal tapered end portion 373 be comprised of
substantially all small-sized cell structures 377 like that shown
in FIG. 39.
[0224] According to some implementations the length of the distal
tapered end portion 373 in the as-cut manufactured state is less
than about 30% of the length of the main body portion 372, and
preferably less than about 25% of the length of the main body
portion 372. In one implementation the lengths of the main body
portion 372 and the distal tapered end portion 373 are about 26 mm
and 6 mm, respectively. In another implementation the distal
tapered end portion 373 has a length of between about 4.5 mm to
about 5.0 mm. According to some implementations the combined length
of the distal tapered end portion 373 and the distal antenna 379 is
less than about 10 mm.
[0225] FIG. 40A shows a two dimensional view of a duct obstruction
retrieval device 380 according to another implementation. Like the
retrieval device 370 shown in FIG. 39, retriever 380 comprises a
distal tapered end portion comprising less than three full rows of
cell structures. Retriever device 380 differs from retriever 370 in
that the distal tapered end portion comprises cell structures that
are bifurcated into a first set of cell structures 386 and a second
set of cell structures 387 with the first cell of cell structures
386 terminating at a first distal antenna 388 and the second set of
cell structures 387 terminating at a second distal antenna 389.
FIG. 40B depicts a three dimensional view of retrieval device 380
with the reference number 383 denoting the distal tapered end
portion of the device. As shown in FIG. 40B, distal antenna 388 and
distal antenna 389 are joined to form a retrieval device having a
distal tapered end portion with a closed end.
[0226] It is important to note that although the retrieval devices
370 and 380 have been described as comprising distal antennas, in
other implementations like retrieval devices are provided without
distal antennas. The same applies to each of the implementations
disclosed and contemplated herein. In addition, with reference to
the retrieval device 380 of FIG. 40, in another implementation only
a single distal antenna is provided that is chosen between distal
antenna 388 and distal antenna 389. In such an implementation the
retrieval device would possess an open distal end with the second
set of cell structures 387 being available to sweep along the
treatment vessel to capture dislodged material.
[0227] FIG. 41 is a two dimensional view of a duct obstruction
retrieval device 390 according to another implementation that
comprises a distal tapered end portion comprising less than three
full rows of cell structures. Like retrieval device 380, the distal
tapered end portion of retrieval device 390 has cell structures
that are bifurcated into a first set of cell structures 396 and a
second set of cell structures 397 with the first cell of cell
structures 396 terminating at a first distal antenna 398 and the
second set of cell structures 397 terminating at a second distal
antenna 399. As shown in FIG. 41, the first and second distal
antennas 398 and 399 are longitudinally off-set from one another.
In one implementation a radiopaque material, feature (e.g., flared
strut) or component (e.g., a coil) is positioned on each of the
first and second antennas. By virtue of there off-set construction,
a radiopaque component, for example, on each of the antennas
enables the distal end of the retrieval device and the distal
tapered end portion of the retrieval device to be visually
delineated during the treatment procedure.
[0228] FIG. 42A is a two dimensional view of a duct obstruction
retrieval device 450 according to another implementation. The
retrieval device 450 comprises an expandable member that has a
proximal tapered end portion 451, a cylindrical main body portion
452 and a distal tapered end portion 453. The outer-most cell
structures in the proximal tapered end portion have outer wall
segments that form first and second rail segments 454 and 455,
respectively. Each of the rail segments 454 and 455 extend from a
proximal-most end of the expandable member to a position at or near
the proximal end of the cylindrical main body portion 452. In the
implementation of FIG. 42, each of the rail segments 454 and 455
are undulating. A proximal antenna 457 extends proximally from a
proximal-most cell structure 456.
[0229] The proximal-most cell structure 456, as shown in greater
detail in FIG. 42B, comprises first and second outer struts 460 and
461, respectively, and first and second inner struts 462 and 463,
respectively. As shown in the layout of FIG. 42B, the first outer
strut 460 and a first portion 461a of the second outer strut 461
are straight in the two dimensional layout while the first inner
strut 462, second inner strut 463 and the second portion 461b of
strut 461 are curvilinear in the two dimensional layout. In the
manufactured, three dimensional configuration the first outer strut
460 and the first portion 461a of the second outer strut 461 are
curved and devoid of undulations. As a result of being oriented at
the proximal end of the expandable member and being co-extensive to
the proximal antenna, the straight strut segments of the
proximal-most cell structure 456 enhance the pushability of the
retrieval device 450 as it is delivered through the anatomy of a
patient as compared to retrieval devices having proximal-most cell
structure with only curved struts in the two dimensional
layout.
[0230] In some implementations, the total length of struts 460 and
462 (L1) and the total length of struts 461 and 463 (L2) are
substantially the same in order to promote a nesting of the struts
when the expandable member transitions from the expanded state to
the unexpanded state. According to some implementations the
difference in length between L1 and L2 is less than 5.0%, while in
other implementations the difference in length between L1 and L2 is
less than 1.0%.
[0231] FIG. 43 illustrates a variation of the proximal-most cell
structure 456. As depicted, each of struts 460 and 461 have an area
of reduced width 464 and 465, respectively, that are located
adjacent their junction 466 with the proximal antenna 457. The
inclusion of the reduced width areas 464 and 465 locally enhances
the proximal-most cell structure's ability to collapse by reducing
the amount of force needed to initiate and effectuate the collapse.
Thus, for example, when the retrieval device 450 is first
introduced into an introducer sheath for placement within a
delivery catheter or is withdrawn into a delivery catheter after
the expandable member has deployed inside a patient, the areas of
reduced width 464 and 465 cause the struts 460 and 461 to be more
easily folded in the area of the junction 466 with less force than
would otherwise be required absent the areas of reduced width. This
makes the retrieval device 450 more manageable when being handled
by healthcare professionals when the retrieval device 450 is being
introduced into the delivery catheter for the first time, thus
reducing the likelihood of the retrieval device being damaged
during the introduction process. As previously discussed, after the
retrieval device 450 has been introduced and expanded inside the
duct of a patient there may be occasions when the retrieval device
is proximally withdrawn back into the delivery catheter. This may
occur, for example, upon the retrieval device being improperly
placed in the duct or upon the completion of a retrieval procedure.
In each of these instances because less force is required to
collapse the expandable member of the retrieval device several
advantages are realized. One advantage is that it reduces the
likelihood of the retrieval device 450 acting upon the delivery
catheter in a manner that would cause an inadvertent displacement
of the delivery catheter within the duct of the patient. Another
advantage is that it reduces the likelihood of excessive force
being applied at the attachment between the proximal antenna 457
and the elongate wire (e.g. elongate wire 40 shown in FIG. 1A) that
would result in a failure at the junction.
[0232] In the implementation of FIG. 43 the areas of reduced width
464 and 465 comprise tapers. In other implementations the areas of
reduced width are denoted by a stepped reduction in strut width.
The amount by which the width is reduced in areas 464 and 465 will
vary according to the nominal widths of struts 460 and 461. In any
event, it is important that the amount of width reduction is
consistent with the radial force and structural integrity
requirements of the expandable member. It has been discovered that
a reduction of width in the as-cut manufactured state of between
about 5.0% and about 20.0% is suitable for struts having a nominal
width of between about 0.0057 inches and about 0.0027 inches, with
a preferable range being between about 10.0% and about 20.0% in
width reduction. In one implementation the width dimension W1 of
struts 460 and 461 is about 0.0053 inches with the minimum width
dimension of the areas of reduced width being 0.0047 inches. In
another implementation the width dimension W1 of struts 460 and 461
is about 0.0057 inches with the minimum width dimension of the
areas of reduced width being 0.0046 inches.
[0233] In some implementations the as-cut width dimensions of
struts 460 and 461 are different, with the width dimension of their
respective areas of reduced width 464 and 465 also being different.
For example, in one implementation strut 460 has a width dimension
of about 0.0050 inches, strut 461 has a width dimension of about
0.0057 inches, and areas of reduce width 464 and 465 have width
dimensions of about 0.0042 inches and about 0.0046 inches,
respectively.
[0234] FIG. 44 shows another variation of the proximal-most cell
structure 457 wherein outer struts 460 and 461 comprise a proximal
section 467, a midsection 468 and a distal section 469. Because the
width dimensions of the outer struts 460 and 461 of the
proximal-most cell structure 456 are generally made greater than
most of struts in the remaining portion of the retrieval device 450
for the purpose of enhancing the pushability of the expandable
member, the bulk of material at the junctures 471 and 472 located
at the distal end of the struts may impede the expandable member's
ability to collapse. For this reason, in the implementation of FIG.
44 the distal sections 469 have a reduced width dimension in order
to reduce the amount of material occupying the juncture regions 471
and 472. Although FIG. 44 also shows the proximal sections 467
having a reduced width dimension (similar to that described above),
in some implementations this is not the case. In a manner described
above, the sections of reduced width may comprise tapers and/or
steps.
[0235] Another advantage of the implementation depicted in FIG. 44
is that the midsection 468 of struts 460 and 461 may be provided
with a sufficient width to enhance the visibility of the device
under fluoroscopy without materially impacting the ability of the
proximal end of the proximal tapered region 451 to collapse or to
otherwise assume its unexpanded state. According to one
implementation the width dimension of the strut midsections 468 is
about 0.0053 inches and the minimum width dimension of the proximal
and distal sections 467 and 469 being 0.0047 inches and 0.0041
inches, respectively. As with some of the FIG. 43 implementations,
in some FIG. 44 implementations the width dimensions of struts 460
and 461 are different, with the width dimension of one or more of
their respective proximal sections, midsections and distal sections
being different.
[0236] FIG. 45A is a two dimensional view of a duct obstruction
retrieval device 800 according to another implementation. The
retrieval device 800 comprises an expandable member that has a
proximal tapered end portion 801, a cylindrical main body portion
802 and a distal tapered end portion 803. The outer-most cell
structures in the proximal tapered end portion have outer wall
segments that form on one side a non-undulating rail segment 804
and on the other side an undulating rail segment 805. Each of the
rail segments 804 and 805 extend from a proximal-most end of the
expandable member to a position at or near the proximal end of the
cylindrical main body portion 802. A proximal antenna 806 extends
proximally from a proximal-most cell structure 807 while a distal
antenna 808 extends distally from the distal end of distal tapered
section 803. The distal tapered section 803 is similar to that
described above in conjunction with FIG. 39. In some
implementations the proximal-most cell structure 807 has the same
features and characteristics as proximal-most cell structure 456 in
the implementations of FIGS. 42-44 above.
[0237] As a result of the diagonal disposition of the cell
structures in the retrieval device, the straight line length along
which rails 804 and 805 pass are different in the as-cut
manufactured state with the straight line length that passes along
rail 804 being longer than the straight line length that passes
along rail 805. The linear configuration of rail 804 in combination
with the undulating configuration of rail 805 advantageously
results in the rails 804 and 805 having lengths that more closely
approach one another when the retrieval device assumes it's
unexpanded/delivery state. According to one implementation, rails
804 and 805 are configured to achieve substantially the same length
when the retrieval device 800 is in the unexpanded/delivery state.
In some implementations, the difference in length between rails 804
and 805 is between about 0% to about 5% when the retrieval device
800 is in the unexpanded/delivery state.
[0238] As discussed earlier, the retrieval devices disclosed and
contemplated herein are generally laser cut from a tube and in
their actual three dimension configuration generally comprise tube
like structures. FIG. 45, like many of the other figures,
represents a retrieval device as it would appear in a two dimension
layout, that is, as if it were cut along its length and laid out on
a flat surface. With this in mind, and with reference to FIG. 45B,
in the two dimension layout the cell structures are polygons
comprising a plurality of struts. As shown, rail segments 804 and
805 are constructed by the outer walls of the outer most cell
structures 807, 810 and 811 in the proximal tapered section 810.
Undulating rail segment 805 is formed by a first outer wall 812 of
the proximal-most cell structure and the outer walls 814 of outer
cell structures 810, whereas the non-undulating rail segment 804 is
formed by a second outer wall 813 of the proximal-most cell
structure and the outer walls 815 of outer cell structures 811. As
represented in FIG. 45B, in the two dimension layout the outer
walls 814 are curvilinear and the outer walls 815 are straight. As
will be appreciated, when in the tubular form, the rail 804 will be
curved when the expandable member assumes an expanded state, but
will nonetheless be devoid of undulations. Rail 805 will also
assume an additional degree of curvature in its three dimensional
state, but unlike rail 804 will comprise undulations.
[0239] An advantage of the proximal tapered section 801 design is
that the non-undulating rail segment 804 provides the
aforementioned benefits related to pushability and kink resistance,
while the undulating rail segment 805 accommodates the inclusion of
a larger number of symmetric-shaped polygons and/or nearly
symmetric-shaped polygons within the section 801. The inclusion of
an increased number of symmetric-shaped and/or nearly
symmetric-shaped polygons in the distal tapered end portion 801
improves its ability to assume it's unexpanded or compressed state
and also provides for a more uniform and compact configuration.
Because symmetrically shaped cell structures have better nesting
tendencies than their non-symmetric counter-parts, the
aforementioned advantages are achieved, at least in part, by the
increased number of symmetrically shaped cell structures disposed
within the proximal tapered end portion 801.
[0240] Another advantage of a proximal tapered end portion having
one non-undulating rail segment 804 and one undulating rail segment
805 is that the inclusion of the undulating rail segment provides
more freedom in the design of the cell structures within the
proximal tapered end portion as opposed to a design having two
non-undulating rails. As shown in FIG. 45B, the outer cell
structures 811, along which the non-undulating rail segment 804 is
formed, comprise structures that are considerably more symmetric
than those, like for example, shown in FIG. 30.
[0241] With reference to FIG. 45C, according to one implementation
the retriever device 800 has the following as-cut dimensional
characteristics: L1=56.44 mm.+-.0.50 mm; L2=26.85 mm.+-.0.50 mm;
L3=2.0 mm.+-.0.1 mm; L4=4.0 mm.+-.0.3 mm; W1=0.0054
inches.+-.0.0004 inches; W2=0.0056 inches.+-.0.0004 inches;
W3=0.0047 inches.+-.0.0004 inches; W4=0.0047 inches.+-.0.0004
inches; W5=0.0040 inches.+-.0.0004 inches; W6=0.0027
inches.+-.0.0004 inches; W7=0.0034 inches.+-.0.0004 inches;
W8=0.0031 inches.+-.0.0004 inches; W9=0.010 inches.+-.0.007 inches;
W10=0.0035 inches.+-.0.0004 inches; W11=0.0025 inches.+-.0.0004
inches. In one implementation the length of the proximal tapered
end portion and the distal tapered end portion is about 13 mm and 7
mm, respectively.
[0242] FIG. 46 illustrates an obstruction retrieval device 830
according to another implementation wherein portions 833 of some
struts 832 in the distal tapered end portion 831 of the retriever
device are flared to enhance the radiopacity of the distal region
of the device. In some implementations during manufacture each of
portions 833 are laser cut so as to possess an enhanced width
dimension with respect to the remainder of strut 832. Besides in
themselves enhancing radiopacity, the flared portions (or portions
of enhanced width) provide a good platform for receiving a
radiopaque coating such as, for example, a gold coating. In the
implementation of FIG. 46 the flared portions 88 are positioned a
sufficient distance from the strut junctions 834 so as to not
interfere with the retriever's ability to compress. In the
implementation of FIG. 46 the flared portions 833 are also
longitudinally staggered so that when the retriever 830 is in the
compressed state no more than a single flared portion 833 will
occupy a longitudinal position. Such a configuration lessons the
impact the flared portions 833 may have on the retriever's lowest
achievable diameter dimension along the distal tapered end portion
831. In the embodiment of FIG. 46, the flared portions comprise
nodes which in one implementation have a diameter of about 0.015
inches. In other embodiments the flared portions 833 are
longitudinal in nature and occupy a substantial length of the
struts 832. In such implementations the flared portions 833 may
have a width of between about 0.0035 inches to about 0.0045
inches.
[0243] FIGS. 47A and 47B illustrate a distal segment of an
obstruction retrieval device 480 according to one implementation.
FIG. 47A depicts the device 480 in a two-dimensional layout as if
it were cut along its length and laid out on a flat surface. While
FIG. 47A depicts the device 480 in its as-cut configuration, the
three-dimensional representation of FIG. 47B shows the device 480
in a post-cut manufactured state.
[0244] With reference to FIG. 47A, the distal segment of device 480
comprises a plurality of distal cell structures 488-491 with a set
of antennas 481, 482 and 483 extending distally from the junction
regions 492-494 of cell structures 488-491. In some implementations
tabs 485-487, or other enhanced dimension features, are provided at
one or more ends of the distal most cell structures for the purpose
of identifying the distal end of the device under fluoroscopy by
virtue of their enhanced dimensional characteristics and/or as a
result of being endowed with a radiopaque material. As shown in
FIG. 47A, in some implementations the distal-most cell structures
are smaller than the adjacent cell structures in the main body
portion of the device 480.
[0245] As shown in FIG. 47B, at a point in time after the device
480 has been formed, such as being cut by a laser, the distal ends
of antennas 481, 482 and 483 are joined together at the juncture
484 so as to provide the internal cavity of device 480 with a
closed-end. In effect, the closed-end forms a basket that
facilitates the collection of particulates, such as embolic
material, that may become dislodged during a retrieval procedure.
In some implementations the juncture 484 is formed by soldering
together the distal ends of the antennas 481-483. In some
implementations the distal ends of the antennas 481-483 are
positioned within an encasement, such as a coil spring or other
perforated structure, with a solder or other bonding agent being
applied within and/or about the encasement to effectuate a bonding
together of the distal ends of the antennas 481-483. In some
implementations the encasement comprises a rounded atraumatic
distal tip. In some implementations the encasement comprises a
radiopaque material.
[0246] FIGS. 48A and 48B illustrate an obstruction retrieval device
850 according to one implementation. FIG. 48A depicts the device
850 in a two-dimensional layout as if it were cut along its length
and laid out on a flat surface. While FIG. 48A depicts the device
850 in its as-cut configuration, the three-dimensional
representation of FIG. 48B shows the device 480 in a post-cut
manufactured state. The device includes a proximal antenna 851, a
proximal taper portion 852, a main body portion 853 and a distal
portion 855. In the as-cut manufactured state the main body portion
853 and the distal portion 855 have the same, or substantially
same, diameter. At a point in time after the device 850 has been
cut, such as by laser cutting, the device 850 is formed so that the
unconstrained configuration of the distal portion 855 has a
diameter that is greater than that of the unconstrained main body
portion 853. The post as-cut form of the device 850 may be achieved
with the use of mandrels or other tools and methods known in the
art. In some implementation the ratio of the unconstrained diameter
of the distal portion 855 (absent the transition portion 854) and
the main body portion 853 is between about 1.2/1.0 and about
2.0/1.0. For example, according to one implementation the average
unconstrained diameter of the main body portion 853 is about 2.0
millimeters and the average unconstrained diameter of the distal
portion 855, absent the transition portion 864, is about 4.0
millimeters. According to some implementations the ratio of the
unconstrained length of the distal portion 855 (absent the
transition portion 854) and the unconstrained length of the main
body portion is between about 0.2 to about 0.7. For example,
according to one implementation the unconstrained length of the
main body portion 855 is between about 15 to 25 millimeters and the
unconstrained length of the distal portion (absent the transition
portion 854) is between about 5 to 10 millimeters.
[0247] According to some implementations, as depicted in FIG. 48A,
the cell structures in the main body portion 853 are larger in size
than those in the distal portion 855. The lower strut density in
the main body portion 853 facilitates an integration of the
retrieval device 850 within an obstruction. The higher strut
density in the distal portion 855 facilitates the entrapment of
dislodge particles as discussed in more detail below. Additionally,
in some implementations the retrieval device is constructed in a
manner that results in a radial force being exerted by the main
body portion 853 that is greater than the radial force exerted by
the distal portion 855 when the retrieval device 850 is deployed
within a duct of a patient. In such an implementation, the main
body portion 853 is situated to capture an obstruction while the
distal portion 855 more gently acts against a wall of the duct
distal to the obstruction to entrap portions of the obstruction
that become dislodged during and after its capture. As such,
according to one method the retrieval device 850 is placed at the
treatment site of a patient by use of a delivery catheter, as
previously disclosed herein. The retrieval device 850 is positioned
at a distal end of the delivery catheter so that the main body
portion 853 is positioned at the site of the obstruction to be
retrieved. When sheathed within the delivery catheter the main body
portion 853 and the distal portion 855 have the same, or
substantially the same, diameter. Thereafter, the delivery catheter
is withdrawn proximally to cause the constrained retrieval device
to expand at the treatment site so that the main body portion 853
is at least partially forced into the obstruction and so that at
least a portion of the distal portion 855 more gently rests against
the duct wall distal to the obstruction. Upon the obstruction being
captured within the main body portion 853 of device 850, the device
may be removed from the patient in a manner consistent with one or
more of the methods previously disclosed herein. During such
removal, as the retrieval device is pulled proximally the distal
portion 855 sweeps along the duct wall to entrap portions of the
obstruction that may have become dislodged. By virtue of its
enhanced diametric dimension, the distal portion 855 maintains
contact with the duct wall during all or a portion of the removal
procedure.
[0248] As discussed above, a lower strut density in the main body
portion 853 facilitates an integration of the retrieval device 850
within an obstruction. However, in some implementations the
retrieval device is constructed in a manner that results in a
radial force being exerted by the main body portion 853 that is
greater than the radial force exerted by the distal portion 855
when the retrieval device 850 is deployed within a duct of a
patient. To achieve this variation in a radial force, in some
implementations the width dimension of the struts in the main body
portion 853 of the retrieval device are cut to have a larger width
dimension of at least some or all of the struts in the distal
portion 855.
[0249] As shown in FIGS. 48A and 48B, in some implementations the
strut density in the distal segment 855 is further enhanced by the
inclusion of non-linear struts 860 in at least some of the cell
structures. In some implementations the non-linear struts extend
between the proximal end 864 and distal end 866 of cell structures.
In some implementations the non-linear struts 860 extend between
the proximal end 864 and distal end 866 of cell structures with the
non-linear strut 861 having substantially the same length as the
upper strut 861 and/or lower strut 862 in the as-cut configuration.
Such a construction enhances the ability of the cell structure
struts to nest resulting in a lower achievable constrained diameter
of the retrieval device. In some implementations the non-linear
struts 861 extend between the proximal end 864 and distal end 866
of cell structures with the upper, lower and non-linear struts 860,
862 and 861, respectively, having substantially the same length in
the as-cut configuration. So as not to greatly impact the radial
force produced in the distal segment 855, in some implementations
the non-linear struts 860 have a width dimension less than the
width dimension of the upper and lower struts 861 and 862. In some
implementations the ratio of the width dimension of struts 860 and
the width dimension of each of the upper and lower struts 861 and
862, respectively, is between about 0.70 and 0.80. For example,
according to one implementation each of the upper and lower struts,
361 and 362, have a width dimension of about 0.0035 inches while
strut 360 has a width dimension of about 0.0025 inches.
[0250] FIG. 49 illustrates a variation to the as-cut configuration
shown in FIG. 48A. As shown in FIG. 49, the retrieval device 870
comprises a proximal distal portion 871, a main body portion 872
and a distal portion 873, the distal portion being shorter in
length than that depicted in FIG. 48A.
[0251] FIG. 50 illustrates a distal segment of a retrieval device
similar to that shown in FIGS. 47A and 47B having one or more
radiopaque wires or ribbons 495 wound about the struts that form
cell structures 488-492. Throughout the remainder of the disclosure
the term "wire" is used broadly to include wires, ribbons, or like
structures. Although the entirety of the cell struts that form cell
structures 488-492 may be wound with one or more radiopaque wires
495 as shown in FIG. 50, in other implementations only a selected
number of struts may possess radiopaque wire windings. An advantage
of incorporating the radiopaque wire windings into the distal
segment of the retrieval device is that it enhances the visibility
of the distal end of the device under fluoroscopy. In addition,
when a sufficient number of distal member struts are endowed with
wire windings, such as shown in FIG. 50, the wire windings enhance
the stiffness of the distal segment. An advantage of increasing the
stiffness of the distal segment is that it inhibits prolapse of the
distal segment as the retrieval device is advanced through a
delivery catheter or treatment duct of a patient. In one
implementation the one or more wires comprise platinum. However, it
is to be appreciated that any of a number of other radiopaque
materials may be used. The one or more wires may comprise a core
structure, such as stainless steel, that is clad or otherwise
coated with a radiopaque material. The one or more wires may also
comprise a polymeric structure impregnated, doped or otherwise
coated with a radiopaque material. In some implementations the
cross-sectional area of the one or more wires varies to provide a
variation in radiopacity and/or stiffness within the distal
segment. In some implementations the diameter or width dimension of
the one or more wires 495 is in the range of between about 20% to
about 50% less than the width dimension of the struts which form
the distal segment.
[0252] Although not shown in FIG. 50, in some implementations small
recesses are provided in at least some of the struts of cell
structures 488-492 for the purpose of guiding the placement of the
wire windings to designated locations. Preferably, the recesses are
sized to receive only a portion of the wire so that only a portion
of the wire resides within the recess and a portion of the wire
resides outside the recess.
[0253] FIGS. 51A through 51D illustrate other aspects of a clot
retrieval device 550 which are in some ways similar to the
retrieval device 850 depicted in FIGS. 48A and 48B. FIGS. 51A-51D
depict the device 550 in a two-dimensional layout as if it were cut
along its length and laid out on a flat surface. The device
includes a proximal antenna 561, a proximal taper portion 551, a
main body portion 552a and a distal portion 552b. In the as-cut
manufactured state the main body portion 552a and the distal
portion 552b have the same, or substantially same, diameter. At a
point in time after the device 550 has been cut, such as by laser
cutting, the device 550 is formed so that the unconstrained
configuration of the distal portion 552b has a diameter that is
greater than that of the unconstrained main body portion 552a. The
post as-cut form of the device 550 may be achieved with the use of
mandrels or other tools and methods known in the art. In some
implementation the ratio of the unconstrained diameter of the
distal portion 552b and the main body portion 552a is between about
1.2/1.0 and about 2.0/1.0. For example, according to one
implementation the average unconstrained diameter of the main body
portion 552a is about 2.0 millimeters and the average unconstrained
diameter of the distal portion 552b is about 4.0 millimeters.
According to some implementations the ratio of the unconstrained
length of the distal portion 552b and the unconstrained length of
the main body portion 552a is between about 0.2 to about 0.7. For
example, according to one implementation the unconstrained length
of the main body portion 552a is between about 15 to 25 millimeters
and the unconstrained length of the distal portion is between about
5 to 10 millimeters.
[0254] According to some implementations, cell structures in the
proximal taper portion 551, main body portion 552 and distal
portion 552b are of different sizes. In the example of FIG. 51A,
the cell sizes are multiples of one another with cell structure 554
comprising an area approximately equal to two of cell structure 553
and cell structure 555 comprising an area approximately equal to
three of cell structures 553. It is important to note that cell
sizes that are multiples of one another are not required. FIG. 51B
illustrates the length dimension L1 and width dimension W1 of cell
structure 553. FIG. 51C illustrates the length dimension L2 and
width dimension W2 of cell structure 554. FIG. 51D illustrates the
length dimension L3 and width dimension W3 of cell structure
555.
[0255] According to some implementations cell structures 553, 554
and 555 each have an average length to width ratio greater than one
when the retrieval device is in an unexpanded state and when the
retrieval device is in an expanded state. The ability of the cell
structures 553, 554, and 555 to maintain an average length to width
ratio of greater than one inhibits the cells from collapsing
lengthwise as the device 550 travels through a delivery catheter or
duct of a patient. In other words, the cell structures of device
550 are inhibited from collapsing lengthwise on themselves in an
accordion like fashion due to their length to width ratios being
greater than one.
[0256] Another aspect is reflected in the length L3 of the cell
structures 555 in the distal portion 552b of the device. Because
the distal portion 552b assumes an expanded diameter that is
greater than the expanded diameter of the remaining portions of the
device, the length dimension L3 is selected to be sufficiently long
in comparison to its width dimension W3 so as to ensure that the
cell structures 555 maintain their length dimension to be greater
than their width dimensions when the retrieval device 550
transitions from an unexpanded to an expanded state.
[0257] In some implementations the average length to width ratio of
the cell structures in the distal portion 552b of the cylindrical
main body portion are greater than the average length to width
ratio of the cell structures in the proximal portion 552a of the
cylindrical main body portion, the average length to width ratio of
the cell structures in the proximal portion 552a of the cylindrical
main body portion being greater than the average length to width
ratio of the cell structures in the proximal end portion 551, and
with the average length to width ratio of the cell structures in
the proximal end portion being greater than one when the
self-expandable member is in the unexpanded and expanded
configuration.
[0258] In some implementations the retrieval device 550 is
constructed in a manner that results in a radial force being
exerted by the main body portion 552a that is greater than the
radial force exerted by the distal portion 552b when the retrieval
device 550 is deployed within a duct of a patient. In such an
implementation, the main body portion 552a is situated to capture
an obstruction while the distal portion 552b more gently acts
against a wall of the duct distal to the obstruction to entrap
portions of the obstruction that become dislodged during and after
its capture. As such, according to one method the retrieval device
550 is placed at the treatment site of a patient by use of a
delivery catheter, as previously disclosed herein. The retrieval
device 550 is positioned at a distal end of the delivery catheter
so that the main body portion 552a is positioned at the site of the
obstruction to be retrieved. When sheathed within the delivery
catheter the main body portion 552a and the distal portion 552b
have the same, or substantially the same, diameter. Thereafter, the
delivery catheter is withdrawn proximally to cause the constrained
retrieval device to expand at the treatment site so that the main
body portion 552a is at least partially forced into the obstruction
and so that at least a portion of the distal portion 552b more
gently rests against the duct wall distal to the obstruction. Upon
the obstruction being captured within the main body portion 552a of
device 550, the device may be removed from the patient in a manner
consistent with one or more of the methods previously disclosed
herein. During such removal, as the retrieval device is pulled
proximally the distal portion 552b may sweep along the duct wall to
entrap portions of the obstruction that may have become dislodged.
By virtue of its enhanced diametric dimension, the distal portion
552b maintains contact with the duct wall during all or a portion
of the removal procedure.
[0259] As discussed above, a lower strut density in the main body
portion 552a (as compared to the strut density in the proximal
taper portion 551) facilitates an integration of the retrieval
device 550 within an obstruction. However, in some implementations
the retrieval device is constructed in a manner that results in a
radial force being exerted by the main body portion 552a that is
greater than the radial force exerted by the distal portion 552b
when the retrieval device 550 is deployed within a duct of a
patient. To achieve this variation in a radial force, in some
implementations the width dimension of the struts in the main body
portion 552a of the retrieval device are cut to have a larger width
dimension of at least some or all of the struts in the distal
portion 552b.
[0260] As shown in FIG. 51A, in some implementations the strut
density in the distal segment 552b is further enhanced by the
inclusion of non-linear struts 562 in at least some of the cell
structures. In some implementations the non-linear struts 562
extend between the proximal end 556 and distal end 557 of cell
structures. In some implementations the non-linear struts 562 (or
intermediate struts) extend between the proximal end 556 and distal
end 557 of cell structures with the non-linear strut 562 having
substantially the same length as the upper strut 558 and/or lower
strut 559 in the as-cut configuration. Such a construction enhances
the ability of the cell structure struts to nest resulting in a
lower achievable constrained diameter of the retrieval device. So
as not to greatly impact the radial force produced in the distal
segment 552b, in some implementations the non-linear struts 562
have a width dimension less than the width dimension of the upper
and lower struts 558 and 559. In some implementations the ratio of
the width dimension of struts 562 and the width dimension of each
of the upper and lower struts 558 and 559, respectively, is between
about 0.70 and 0.90. For example, according to one implementation
each of the upper and lower struts, 558 and 559, have an as-cut
width dimension of about 0.0035 inches while strut 562 has an
as-cut width dimension of about 0.0025 inches.
[0261] Although not shown in FIGS. 51A-51D, in some implementations
the cell structures in the distal segment 552b have wire windings
selectively woven through their struts in order to endow the distal
segment with a desired radiopacity and/or stiffness as discussed
above in relation to FIG. 50.
[0262] In some implementation, a plurality of antennas 560a, 560b
and 560c extend distally to the distal-most circumferential row of
cell structures in the distal segment 552b. In a manner like that
disclosed above in conjunction with the device of FIGS. 47A and
47B, the distal ends of antennas 560a, 560b and 560c are joined
together so as to provide the internal cavity of device 550 with a
partially closed-end. In effect, the closed-end forms a basket that
facilitates the collection of particulates, such as embolic
material, that may become dislodged during a retrieval procedure.
In some implementations the juncture of antennas 560a, 560b and
560c is formed by soldering together the distal ends of the
antennas. In some implementations the distal ends of the antennas
are positioned within an encasement, such as a coil spring or other
perforated structure, with a solder or other bonding agent being
applied within and/or about the encasement to effectuate a bonding
together of the distal ends of the antennas. In some
implementations the encasement comprises a rounded atraumatic
distal tip. In some implementations the encasement comprises a
radiopaque material.
[0263] FIG. 52A illustrates a retrieval device similar to that
disclosed in FIGS. 51A-51D. A difference lies in the construction
of the non-linear/intermediate struts 570 that are disposed in the
distal segment cell structures 555. As shown in FIG. 52A, the
intermediate strut 570 comprises first and second curvilinear
elements 571 and 572, respectively, between which are bifurcation
struts 573a and 573b. An advantage of the configuration of strut
570 is that it provides additional coverage, as compared to strut
562, to assist in entrapping embolic debris. In some
implementations the non-linear struts extend between the proximal
end 556 and distal end 557 of cell structures 555. In some
implementations the non-linear strut 570 extends between the
proximal end 556 and distal end 557 of cell structures with the
combined length of elements 571, 572 and 573a being approximately
the same length as the upper strut 558 and/or the combined length
of elements 571, 572 and 573b being substantially the same length
as the lower strut 559 in the as-cut configuration. So as not to
greatly impact the radial force produced in the distal segment
552b, in some implementations the non-linear struts 570 have a
width dimension less than the width dimension of the upper and
lower struts 558 and 559. In some implementations the ratio of the
width dimension of struts 570 and the width dimension of each of
the upper and lower struts 558 and 559, respectively, is between
about 0.70 and 0.90. For example, according to one implementation
each of the upper and lower struts, 558 and 559, have an as-cut
width dimension of about 0.0035 inches while strut 360 has an
as-cut width dimension of about 0.0025 inches.
[0264] FIG. 52B illustrates a variation to the retrieval device
shown in FIG. 52A with differences existing in the size of the cell
structures 579 in the proximal section 575 of the cylindrical body
portion and the inclusion of cell structure 577 in the distal
section 576 of the cylindrical body portion. As shown in FIG. 52B,
cell structures 579 are smaller in size to the similarly situated
cell structures in the retrieval device of FIG. 52A as a result of
additional struts being added (those depicted by dashed lines) to
essentially reduce the size of the cell structures by half. As
noted above, another difference lies in the inclusion of cell
structure 577 at the distal end of the retrieval device to provide
a the device with a substantial uniform circumferential end. In one
implementation an intermediate strut 578 extends between the
opposite ends of cell structure 577 in a manner similar to that
described above with respect to intermediate struts 562.
[0265] FIG. 53 illustrates a retrieval device 580 that comprises
different size cell structures along its length, similar to that
disclosed above in conjunction with the device 550 illustrated in
FIGS. 51A-51D. FIG. 53 depicts the device 580 in a two-dimensional
layout as if it were cut along its length and laid out on a flat
surface. The device includes a proximal antenna 581, a proximal
taper portion 582, a main body portion 583 and a distal portion
584. In the as-cut manufactured state the main body portion 583 and
the distal portion 584 have the same, or substantially same,
diameter. At a point in time after the device 580 has been cut,
such as by laser cutting, the device 580 is formed so that the
unconstrained configuration of the distal portion 584 has a
diameter that is greater than that of the unconstrained main body
portion 583. The post as-cut form of the device 580 may be achieved
with the use of mandrels or other tools and methods known in the
art. In some implementation the ratio of the unconstrained diameter
of the distal portion 584 and the main body portion 583 is between
about 1.2/1.0 and about 2.0/1.0. For example, according to one
implementation the average unconstrained diameter of the main body
portion 583 is about 2.0 millimeters and the average unconstrained
diameter of the distal portion 584 is about 4.0 millimeters.
[0266] As illustrated in FIG. 53, the cell structures in the
proximal taper portion 582, main body portion 583 and distal
portion 584 are of different sizes. In the example of FIG. 53, the
cell sizes are multiples of one another with cell structures 586
comprising an area approximately equal to two of cell structure 585
and cell structure 587 comprising an area approximately equal to
three of cell structures 585. It is important to note that cell
sizes that are multiples of one another are not required. As with
cell structures 553, 554 and 555 in device 550 described above,
cell structures 585, 586 and 587 each have an average length to
width ratio greater than one when the retrieval device 580 is in an
unexpanded state and when the retrieval device 580 is in an
expanded state. As discussed above, the ability of the cell
structures to maintain an average length to width ratio of greater
than one inhibits the cells from collapsing lengthwise as the
retrieval device travels through a delivery catheter or duct of a
patient. In other words, the cell structures of device 580 are
inhibited from collapsing lengthwise on themselves in an accordion
like fashion due to their length to width ratios being greater than
one.
[0267] Another aspect is reflected in the length of the cell
structures 587 in the distal portion 584 of the device. Because the
distal portion 584 assumes an expanded diameter that is greater
than the expanded diameter of the remaining portions of the device,
the length dimension of cell structure 587 is selected to be
sufficiently long in comparison to its width dimension so as to
ensure that the cell structure maintains its length dimension to be
greater than its width dimensions when the retrieval device 580
transitions from an unexpanded to an expanded state.
[0268] In some implementations the retrieval device 580 is
constructed in a manner that results in a radial force being
exerted by the main body portion 583 that is greater than the
radial force exerted by the distal portion 584 when the retrieval
device 580 is deployed within a duct of a patient. In such an
implementation, the main body portion 583 is situated to capture an
obstruction while the distal portion 584 more gently acts against a
wall of the duct distal to the obstruction to entrap portions of
the obstruction that become dislodged during and after its capture.
As such, according to one method the retrieval device 580 is placed
at the treatment site of a patient by use of a delivery catheter,
as previously disclosed herein. The retrieval device 580 is
positioned at a distal end of the delivery catheter so that the
main body portion 583 is positioned at the site of the obstruction
to be retrieved. When sheathed within the delivery catheter the
main body portion 583 and the distal portion 584 have the same, or
substantially the same, diameter. Thereafter, the delivery catheter
is withdrawn proximally to cause the constrained retrieval device
to expand at the treatment site so that the main body portion 583
is at least partially forced into the obstruction and so that at
least a portion of the distal portion 584 more gently rests against
the duct wall distal to the obstruction. Upon the obstruction being
captured within the main body portion 583 of device 580, the device
may be removed from the patient in a manner consistent with one or
more of the methods previously disclosed herein. During such
removal, as the retrieval device is pulled proximally the distal
portion 584 may sweep along the duct wall to entrap portions of the
obstruction that may have become dislodged. By virtue of its
enhanced diametric dimension, the distal portion 584 maintains
contact with the duct wall during all or a portion of the removal
procedure.
[0269] Although not shown in FIG. 53, in some implementations the
cell structures in the distal segment 584 have wire windings
selectively woven through their struts in order to endow the distal
segment with a desired radiopacity and/or stiffness as discussed
above in relation to FIG. 50.
[0270] The retrieval device 590 illustrated in FIG. 54 is similar
to device 580 with a difference being the manner in which the cell
structures 587 are interconnected. Cell structures 587 have a
proximal side 591, a distal side 592, a top side 593 and a bottom
side 594. As shown in FIG. 54, cell structures 587 are coupled with
the adjoining cell structures 586 along at least a portion of the
proximal side 591. However, the top and bottom sides 593 and 594 of
cell structures 587 are unattached. As mentioned above, it is
desirable that the length to width ratio of cell structures 587
remain greater than one when the retrieval device 590 is moved
through a delivery catheter or duct of a patient. By de-coupling
the top and bottom sides of the cell structures, forces that would
normally be applied to the cell structures during expansion to
cause them to appreciably expand in width are largely removed. This
assists in ensuring that the length to width ratio of cell
structures 587 remains greater than one when the device 590 assumes
an expanded state. As shown in FIG. 55, as a result of the
de-coupling of the distal-most circumferential row of cell
structures, the selection of smaller sized cell structures is
accommodated. For example, as shown in FIG. 55 the distal-most
circumferential row of cell structures 596 may comprise cell
structures that are the same or similar to proximally situated cell
structures 586. It is appreciated, however, that the size and shape
of the distal-most circumferential row of cell structures need not
mimic those of the proximally situated cell structures.
[0271] Turning now to FIG. 56A, a retrieval device 630 is shown
having a similar construction as the device 800 depicted in FIG.
45A, albeit with fewer cell structures and for use in smaller
diameter vessels/ducts. FIG. 56A is a two dimensional view of a
retrieval device 630 according to another implementation. The
retrieval device 630 comprises an expandable member that has a
proximal tapered end portion 631, a cylindrical main body portion
632 and a distal tapered end portion 633. The outer-most cell
structures in the proximal tapered end portion have outer wall
segments that form on one side a non-undulating rail segment 636
and on the other side an undulating rail segment 637. Each of the
rail segments 636 and 637 extend from a proximal-most end of the
expandable member to a position at or near the proximal end of the
cylindrical main body portion 632. A proximal antenna 634 extends
proximally from a proximal-most cell structure 638 while a distal
antenna 635 extends distally from the distal end of distal tapered
section 633. The cell structures 640 in the cylindrical main body
portion 632 comprise facing proximal and distal flexure elements
641 and 642, respectively, which generally comprise convex and/or
concave like structures, such as for example V-like and U-like
structures. The proximal and distal flexure elements 641 and 642
are interconnected by a pair of diagonally extending and
circumferentially spaced-apart struts 643 and 644.
[0272] FIG. 56B shows the as-cut width dimensions in inches of the
various struts in the proximal tapered end portion 631 according to
one implementation, each of the dimensions having a tolerance of
.+-.0.0004 inches. According to one implementation the struts in
the proximal tapered end portion 631 have an as-cut thickness
dimension of about 0.0045.+-.0.0004 inches.
[0273] As previously discussed, it is desirable that the
cylindrical main body portion 632 possess sufficient radial
strength to cause at least a partial integration of its struts into
an obstruction targeted for full or partial removal. However, the
radial strength of the cylindrical main body portion 632 must be
sufficiently low to avoid undue damage to the vessel or duct under
treatment. In order to achieve a desired radial strength the
cross-sectional area and/or width and/or thickness of the struts
that form the cylindrical main body portion 632 must be properly
dimensioned.
[0274] Another feature of consideration is that of flexibility. The
cylindrical main body portion 632 should possess sufficient
flexibility to permit the retrieval device 630 to be advanced and
retracted though the tortuous anatomy of a patient. However, the
cylindrical main body portion 632 should also possess sufficient
stiffness to permit it to be pushed through a delivery catheter and
a duct of a patient without it collapsing on itself. It has been
discovered that stiffness also plays a factor in the ability of the
retrieval device to be withdrawn into a delivery catheter at a
point in time after it has been deployed. As discussed above, upon
a misplacement of the retrieval device within a duct of a patient,
and sometimes upon removal of the retrieval device from the
patient, the retrieval device is fully or partially withdrawn back
into the delivery catheter. It has been discovered that in the
absence of a requisite amount of stiffness within the cylindrical
main body portion it is difficult to withdraw the retrieval device
back into the delivery catheter after it has been deployed. Tests
have shown that in some situations when all the struts within the
cylindrical main body portion have a uniform cross-section,
insufficient stiffness results when the struts are sized to achieve
a proper amount of radial force.
[0275] It has been discovered that the cross-section of flexure
elements 641 and 642 most significantly impact radial force in the
cylindrical main body portion 632 while the cross-section of
diagonally disposed struts 643 and 644 contributing little if any
to the radial force produced within the cylindrical main body
portion 632. According to some implementations, in order to achieve
the right combination of radial strength and stiffness within the
cylindrical main body portion 632, the cross-section of flexure
elements 641 and 642 is different than the cross-section of struts
643 and 644. Because in many instances the retrieval device is cut
from a tube of uniform thickness, the width dimensions of the
flexure elements 641, 642 and diagonally disposed struts 643, 644
are varied to achieve the desired radial force and stiffness
characteristics. However, it is to be appreciated that dimensions
other than width may be varied to achieve the same or similar
results.
[0276] According to some implementations all or substantially all
of the struts in the cylindrical main body portion 632 are of the
same thickness with the flexure elements 641 and 642 having a first
average width dimension and the diagonally disposed struts 643 and
644 having a second average width dimension that is greater than
the first average width dimension. The second average width
dimension is sufficiently large to compensate for the lack of
stiffness that would otherwise exists if the second average width
dimension was the same as the first average width dimension. In
some implementations the as-cut second average width dimension is
in the range of about 1.1 to about 2.0 times greater than the
as-cut first average width dimension. In other implementations the
as-cut second average width dimension is in the range of about 1.2
to about 1.5 times greater than the as-cut first average width
dimension. According to one experiment the as-cut first average
width dimension was about 0.0032 inches and the as-cut second
average width dimension was about 0.0040 inches. The results showed
that the average deflection stiffness of the cylindrical main body
portion 632 increased by about a 40% to 50% as a result of
increasing the width dimension of the diagonally disposed struts
643 and 644 from 0.0032 inches to 0.0040 inches. This occurs
without an appreciable increase in radial force.
[0277] FIG. 57 is illustrates a retrieval device 650 similar to
retrieval device 630 with a difference being in the construction of
the diagonally disposed struts 643 and 644. As shown in the
figures, struts 643 and 644 in retrieval device 630 are curvilinear
while struts 643 and 644 in retrieval device 650 are straight.
[0278] According to some implementations the width dimensions of
the diagonally disposed struts 643 and 644 are uniform along their
length. With respect to the example dimensions above, it would mean
that the entire length of struts 643 and 644 would have an average
width dimension of 0.0040 inches. In other implementations struts
643 and 644 comprise middle segments that are disposed between
opposite proximal and distal end segments, with the proximal end
segments being coupled to the proximal flexure element and the
distal end segments being coupled to the distal flexure element.
Using the same example dimensions above, the flexure elements 641
and 642 along with the proximal and distal segments of struts 643
and 644 may have an average width dimension of 0.0032 inches while
the middle segment of struts 643 and 644 may have an average width
dimension of 0.0040 inches. In other implementations struts 643 and
644 comprise middle segments that are disposed between opposite
proximal and distal tapered end segments, with the proximal tapered
end segments being coupled to the proximal flexure element 641 and
the distal tapered end segments being coupled to the distal flexure
element 642. Using the same example dimensions above, the flexure
elements 641 and 642 may have an average width dimension of 0.0032
inches with the middle segment of struts 643 and 644 having an
average width dimension of 0.0040 inches, the average width
dimension of the proximal and distal tapered end segments
transitioning from 0.0032 inches to 0.0040 inches.
[0279] As disclosed above in the description of the device depicted
in FIG. 50, a process of weaving/winding a wire or ribbon about the
struts of the retrieval device may be used for the purpose of
enhancing the radiopacity of the device and also for affecting the
stiffness of the device. In the implementations disclosed above,
the discussion was limited to incorporating such a feature into the
distal segment of retrieval devices. What follows is a description
that involves the use of such wire windings in other portions of
the device.
[0280] FIG. 58A illustrates a retrieval device 630 that has a
similar construction to the retrieval device 650 shown in FIG. 56.
The retrieval device 660 comprises wires that are wound about
selective struts for the purpose of enhancing the radiopacity of
the device 660 and/or to affect the stiffness of one or more
portions of the device. In the exemplary implementation of FIG. 58A
three radiopaque wires (or ribbons) 661, 662 and 663 are woven
along the length of the retrieval device to enhance the radiopacity
of the device along essentially its entire length and to enhance
the stiffness of at least the cylindrical main body portion 666. In
the implementation of FIG. 58A the wires 661-663 are woven about
the diagonally downward oriented struts (as viewed from left to
right) in the cylindrical main body portion 666 so that only the
short legs 670a of the flexure elements 670 possess wire windings.
As shown in detail in FIG. 58B, the long legs 670b of the flexure
elements 670 are free or substantially free of wire windings. A
virtue of this winding configuration is that it enables the wires
to be applied to the retrieval device, and particularly the
cylindrical main body portion 666, in a manner that
disproportionally affects stiffness and radial force. For example,
the average deflection stiffness of the cylindrical main body
portion 666 may be moderately to significantly increased without
there being a corresponding increase in the radial force exerted by
the cylindrical main body portion when it is in an unexpanded
state. Prototypes have shown that the average deflection stiffness
of the cylindrical main body portion 666 may be increased by up to
50% with there being relatively little to no increase in the radial
force.
[0281] According to one exemplary implementation, the struts in the
cylindrical main body portion 666 have an as-cut thickness
dimension of about 0.0045 inches with each of struts 670a, 670b and
671 having width dimensions of about 0.0032, 0.0032 and 0.0040
inches, respectively. In one implementation the wires comprise
platinum with a width and/or diameter of between about 0.0020
inches and 0.0025 inches with there being an average of about one
to ten windings per strut, and most generally one to five windings
per strut. It is to be appreciated that a single wire or any
multiple thereof may be used in lieu of the three wire
configurations depicted in FIG. 58A. Moreover, it is important to
note that, in the case of enhancing radiopacity that the wire or
wires may comprise any radiopaque material or combination of
materials as discussed above in conjunction with FIG. 50. In the
event that wire windings are applied only for the purpose of
affecting stiffness, the wire or wires may comprise any material
suitable for such purpose, such as for example metallic, polymeric
and composite materials. In some implementations the
cross-sectional area of the one or more wires varies to provide a
variation in radiopacity and/or stiffness along the length of the
device.
[0282] According to some implementations, the cylindrical main body
portion 666 has a first average deflection stiffness in the absence
of the one or more wires or ribbons 661-663 and a second average
deflection stiffness with presence of the one or more wires or
ribbons 661-663, the dimensional and material characteristics of
the one or more wires or ribbons 661-663 and the number of windings
per unit length of the diagonally extending and circumferentially
spaced-apart struts in the cylindrical main body portion selected
to cause the second average deflection stiffness to be greater than
the first average deflection stiffness by a factor of between about
1.2 to about 1.8 with there being a disproportionally lower
increase in the radial force exerted by the cylindrical main body
portion when it is in an unexpanded state.
[0283] According to some implementations the proximal and distal
end segments of wires 661-663 are coupled to the retriever device
660 as depicted in FIG. 59 and FIG. 60, respectively. It is
important to note that other attachment/coupling configurations are
also possible. FIG. 59A illustrate the proximal attachment of wires
661-663 at the location where the distal end of elongate wire 40
(see for example FIG. 1A) is attached to the proximal antenna 675.
In one embodiment, the distal end of wire 40 has a flat profile
with a width of about 0.005 inches with the width and thickness of
the proximal antenna 675 being about 0.0063 and about 0.0035
inches, respectively. FIG. 59B illustrates a cross-sectional view
of the resulting joint where in one implementation the proximal
ends of wires 661-663 reside on a bottom side of proximal antenna
675 and the distal end of elongate wire 40 resides on a top side of
proximal antenna 675.
[0284] In one implementation, the distal end of elongate wire 40,
the proximal ends of wires 661-663 and the proximal antenna 675 are
coupled together within a coil structure 680. In one implementation
the coil structure 680 has a closely wrapped distal segment 680a,
and a loosely wrapped proximal segment 680b that includes one or
more gaps 680c. In one implementation, the length of proximal
antenna 675 and the coil 680 are substantially equal. Upon the coil
680 being placed over the overlapping components a bonding agent is
introduced into the internal cavity of the coil 680 to bond the
elongate wire 40, proximal antenna 675 and wires 661-663 together
with at least a portion of the coil. In one implementation, the end
segments of wires 661-663 reside entirely within distal coil
segment 680a. The bonding agent may be an adhesive, solder, or any
other suitable bonding agent. When the bonding agent is a solder, a
preceding step in the process may involve coating the various
components with tin or another suitable wetting agent. In one
implementation the solder is gold and is used to enhance the
radiopacity of the joint so that the joint may serve as a proximal
radiopaque marker. This implementation is particularly applicable
in situations where wires 661-663 are non-radiopaque. In addition
to the use of gold, all or portions of the coil may be made of a
radiopaque material to further enhance the radiopacity of the
joint. In other implementations, in lieu of the use of a single
coil 680, two or more coils in abutting relationship are used with,
for example, a distal closely wound coil and a proximal loosely
wound coil with gaps situated proximal to the closely wound
coil.
[0285] FIGS. 60A and 60B illustrate several methods by which the
distal end segments of wires 661-663 may be attached to the distal
antenna 676. In the implementation of FIG. 60A the distal ends of
wires 661-663 are bonded directly to the distal antenna by use of a
bonding agent such as solder or glue. FIG. 60B shows another
implementation where the distal ends of wires 661-663 are
interposed between the distal antenna 676 and a coil 685 that
surrounds it. In such an implementation a bonding agent may be
introduced into the interior of the coil 685 to effectuate a
bonding together the coil 685, distal antenna 676 and wires
661-663.
[0286] While the above description contains many specifics, those
specifics should not be construed as limitations on the scope of
the disclosure, but merely as exemplifications of preferred
embodiments thereof. For example, dimensions other than those
listed above are contemplated. For example, retrieval devices
having expanded diameters of any where between 1.0 and 100.0
millimeters and lengths of up to 5.0 to 10.0 centimeters are
contemplated. Moreover, it is appreciated that many of the features
disclosed herein are interchangeable among the various
implementations. Those skilled in the art will envision many other
possible variations that are within the scope and spirit of the
disclosure. Further, it is to be appreciated that the delivery of a
vascular treatment device of the implementations disclosed herein
is achievable with the use of a catheter, a sheath or any other
device that is capable of carrying the device with the expandable
member in a compressed state to the treatment site and which
permits the subsequent deployment of the expandable member at a
vascular treatment site. The vascular treatment site may be (1) at
the neck of an aneurysm for diverting flow and/or facilitating the
placement of coils or other like structures within the sack of an
aneurysm, (2) at the site of an embolic obstruction with a purpose
of removing the embolic obstruction, (3) at the site of a stenosis
with a purpose of dilating the stenosis to increase blood flow
through the vascular, etc.
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