U.S. patent application number 13/617308 was filed with the patent office on 2013-01-10 for implant retrieval system.
This patent application is currently assigned to ATRITECH, INC.. Invention is credited to Andrew G.C. Frazier, Alexander K. Khairkhahan, Alan R. Klenk, Marc S. Kreidler, Stewart M. Kume, Darrell H. Ogi, Chad C. Roue, Erik J. van der Burg.
Application Number | 20130012982 13/617308 |
Document ID | / |
Family ID | 21870043 |
Filed Date | 2013-01-10 |
United States Patent
Application |
20130012982 |
Kind Code |
A1 |
Khairkhahan; Alexander K. ;
et al. |
January 10, 2013 |
IMPLANT RETRIEVAL SYSTEM
Abstract
Disclosed is an adjustable occlusion device for use in a body
lumen such as the left atrial appendage. The occlusion device is
removably carried by a deployment catheter. The device may be
enlarged or reduced to facilitate optimal placement or removal.
Methods are also disclosed.
Inventors: |
Khairkhahan; Alexander K.;
(Palo Alto, CA) ; Frazier; Andrew G.C.; (Mountain
View, CA) ; Klenk; Alan R.; (San Jose, CA) ;
Kreidler; Marc S.; (Sunnyvale, CA) ; Kume; Stewart
M.; (Belmont, CA) ; Ogi; Darrell H.;
(Sunnyvale, CA) ; Roue; Chad C.; (Fremont, CA)
; van der Burg; Erik J.; (Sunnyvale, CA) |
Assignee: |
ATRITECH, INC.
Plymouth
MN
|
Family ID: |
21870043 |
Appl. No.: |
13/617308 |
Filed: |
September 14, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10441600 |
May 19, 2003 |
8287563 |
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13617308 |
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|
10033371 |
Oct 19, 2001 |
7044134 |
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10441600 |
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09435562 |
Nov 8, 1999 |
7128073 |
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10033371 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 17/12122 20130101;
A61B 17/12022 20130101; A61M 2210/125 20130101; A61B 17/12172
20130101; A61M 25/10 20130101; A61F 2/01 20130101; A61B 2017/00592
20130101; A61B 17/122 20130101; A61B 2017/00597 20130101; A61F
2230/0071 20130101; A61B 2017/12095 20130101; A61F 2/011 20200501;
A61B 2017/081 20130101; A61B 17/0057 20130101; A61B 2017/00623
20130101; A61B 2017/00579 20130101; A61F 2002/018 20130101; A61F
2230/008 20130101; A61B 2017/00575 20130101; A61B 2017/1205
20130101; A61B 2017/00619 20130101; A61B 2017/00243 20130101; A61M
2025/1054 20130101; A61B 2017/00615 20130101; A61F 2230/0006
20130101; A61B 2017/00557 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61F 2/01 20060101
A61F002/01 |
Claims
1. (canceled)
2. An implantable occlusion device comprising: a proximal occluding
member having a compressed configuration and a radially expanded
configuration, the occluding member being biased to the radially
expanded configuration; a distal stabilizing member having a
compressed configuration and a radially expanded configuration, the
stabilizing member being biased to the radially expanded
configuration; a hinge element disposed between the proximal
occluding member and the distal stabilizing member; and a plurality
of axially-extending struts disposed between the proximal occluding
member and the distal stabilizing member; wherein the occluding
member includes a barrier disposed on a frame.
3. The implantable occlusion device of claim 2, wherein the hinge
element is disposed adjacent the proximal occluding member and the
plurality of axially-extending struts is disposed between the hinge
element and the distal stabilizing member.
4. The implantable occlusion device of claim 2, wherein the distal
stabilizing member includes a plurality of legs, wherein in the
radially expanded configuration, the plurality of legs is inclined
radially outwardly in a proximal direction.
5. The implantable occlusion device of claim 4, wherein the
plurality of legs each terminate at an atraumatic proximal end.
6. The implantable occlusion device of claim 4, wherein the
plurality of legs and the plurality of axially-extending struts are
each formed from a single piece of tubular material.
7. The implantable occlusion device of claim 2, wherein the hinge
element is configured to orient a longitudinal axis of the
occluding member at a non-coincident angle relative to a
longitudinal axis of the stabilizing member.
8. The implantable occlusion device of claim 2, wherein the hinge
element includes a coil member.
9. The implantable occlusion device of claim 8, wherein the coil
member and the plurality of axially-extending struts are each
formed from a single piece of tubular material.
10. The implantable occlusion device of claim 2, wherein the
barrier comprises a first layer of porous polymer material and a
second layer of porous polymer material.
11. The implantable occlusion device of claim 10, wherein the
barrier comprises a third porous layer disposed between the first
layer and the second layer.
12. The implantable occlusion device of claim 2, wherein when the
occluding member is in the radially expanded configuration, the
occluding member has a diameter and a length, wherein the diameter
is greater than the length.
13. A method of manufacturing an implantable occlusion device,
comprising: obtaining a single tubular member; laser cutting the
single tubular member to form a proximal expandable frame, a hinge
element disposed distally of the frame, a plurality of
axially-extending struts disposed distally of the hinge element,
and a distal hub disposed at a distal end of the struts; modifying
the frame to include a self-bias towards a radially expanded
orientation; and attaching a barrier to the frame.
14. The method of claim 13, further including laser cutting the
single tubular member to form a plurality of legs extending
proximally from the distal hub.
15. The method of claim 14, wherein the plurality of legs is
circumferentially interspersed between the plurality of
axially-extending struts.
16. The method of claim 14, further including modifying the
plurality of legs to include a self-bias towards a radially
expanded orientation in which the plurality of legs is inclined
radially outwardly in a proximal direction.
17. The method of claim 14, wherein the plurality of legs include
different lengths.
18. The method of claim 13, wherein the expandable frame includes a
plurality of spokes and the barrier includes a first porous layer
bonded to a second porous layer around the plurality of spokes.
19. The method of claim 18, wherein the plurality of spokes each
terminate at an end contained within the barrier.
20. The method of claim 18, wherein the plurality of spokes each
terminate at an end extending beyond the barrier.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/441,600, filed May 19, 2003, which is a
divisional of U.S. patent application Ser. No. 10/033,371, filed
Oct. 19, 2001, now U.S. Pat. No. 7,044,134, which is a
continuation-in-part of U.S. patent application Ser. No.
09/435,562, filed Nov. 8, 1999, now U.S. Pat. No. 7,128,073, the
disclosures of which are incorporated in their entirety herein by
reference.
BACKGROUND OF THE INVENTION
[0002] Embolic stroke is the nation's third leading killer for
adults, and is a major cause of disability. There are over 700,000
strokes per year in the United States alone. Of these, roughly
100,000 are hemoragic, and 600,000 are ischemic (either due to
vessel narrowing or to embolism). The most common cause of embolie
stroke emanating from the heart is thrombus formation due to atrial
fibrillation. Approximately 80,000 strokes per year are
attributable to atrial fibrillation. Atrial fibrillation is an
arrhythmia of the heart that results in a rapid and chaotic
heartbeat that produces lower cardiac output and irregular and
turbulent blood flow in the vascular system. There are over five
million people worldwide with atrial fibrillation, with about four
hundred thousand new cases reported each year. Atrial fibrillation
is associated with a 500 percent greater risk of stroke due to the
condition. A patient with atrial fibrillation typically has a
significantly decreased quality of life due, in part, to the fear
of a stroke, and the pharmaceutical regimen necessary to reduce
that risk.
[0003] For patients who develop atrial thrombus from atrial
fibrillation, the clot normally occurs in the left atrial appendage
(LAA) of the heart. The LAA is a cavity which looks like a small
finger or windsock and which is connected to the lateral wall of
the left atrium between the mitral valve and the root of the left
pulmonary vein. The LAA normally contracts with the rest of the
left atrium during a normal heart cycle, thus keeping blood from
becoming stagnant therein, but often fails to contract with any
vigor in patients experiencing atrial fibrillation due to the
discoordinate electrical signals associated with AF. As a result,
thrombus formation is predisposed to form in the stagnant blood
within the LAA.
[0004] Blackshear and Odell have reported that of the 1288 patients
with non-rheumatic atrial fibrillation involved in their study, 221
(17%) had thrombus detected in the left atrium of the heart.
Blackshear J L, Odell J A., Appendage Obliteration to Reduce Stroke
in Cardiac Surgical Patients With Atrial Fibrillation. Ann Thorac.
Surg., 1996. 61(2):755-9. Of the patients with atrial thrombus, 201
(91%) had the atrial thrombus located within the left atrial
appendage. The foregoing suggests that the elimination or
containment of thrombus formed within the LAA of patients with
atrial fibrillation would significantly reduce the incidence of
stroke in those patients.
[0005] Pharmacological therapies for stroke prevention such as oral
or systemic administration of warfarin or the like have been
inadequate due to serious side effects of the medications and lack
of patient compliance in taking the medication. Invasive surgical
or thorascopic techniques have been used to obliterate the LAA,
however, many patients are not suitable candidates for such
surgical procedures due to a compromised condition or having
previously undergone cardiac surgery. In addition, the perceived
risks of even a thorascopic surgical procedure often outweigh the
potential benefits. See Blackshear and Odell, above. See also
Lindsay B D., Obliteration of the Left Atrial Appendage: A Concept
Worth Testing, Ann Thorac. Surg., 1996. 61(2):515.
[0006] Despite the various efforts in the prior art, there remains
a need for a minimally invasive method and associated devices for
reducing the risk of thrombus formation in the left atrial
appendage.
SUMMARY OF THE INVENTION
[0007] There is provided in accordance with one aspect of the
present invention an adjustable occlusion device deployment system,
for implanting an occlusion device within a tubular structure in
the body. The system comprises an occlusion device, movable between
a reduced cross section and an enlarged cross section. A deployment
catheter is provided, releasably attached to the occlusion device.
A releasable lock for retaining the occlusion device is provided on
the catheter, along with a core, for changing the cross section of
the occlusion device.
[0008] The occlusion device comprises an expandable frame, which
may have at least two and preferably at least about six spokes. In
one embodiment, the occlusion device has sixteen spokes. Each spoke
is moveable from an axial orientation when the occlusion device is
in a reduced cross section, to an inclined orientation when the
occlusion device is in an enlarged cross section. Preferably, at
least one tissue attachment element is provided on the occlusion
device.
[0009] In accordance with another aspect of the present invention,
there is provided an occlusion device for occluding a tubular body
structure. The device comprises a plurality of spokes, which are
moveable between an axial orientation and an inclined orientation.
A threaded aperture is carried by the device, and a stop surface is
also carried by the device. A threaded core is rotatable within the
aperture, to cause the core to contact the stop surface and axially
elongate the device.
[0010] In accordance with a further aspect of the present
invention, there is provided an implantable device. The device
comprises a radially enlargeable frame having a proximal end and a
distal end. A proximally facing stop surface is provided within the
frame, and a threaded aperture is positioned in the frame,
proximally of the stop surface. Distal axial advancement of a
threaded core through the threaded aperture distally advances the
stop surface, thereby axially elongating and radially reducing the
implantable device. In one embodiment, the implantable device is an
occlusion device. In an alternate embodiment, the implantable
device is a filter.
[0011] In accordance with another aspect of the present invention,
there is provided an occlusion device implantation system. The
system comprises a deployment catheter, having an elongate flexible
body with a proximal end and a distal end. An anti-rotation lock is
provided on the body. A rotatable core extends axially through the
body, and a radially expandable implant is releasably connected to
the distal end of the body.
[0012] In accordance with a further aspect of the present
invention, there is provided a method of implanting a device in the
left atrial appendage. The method comprises the steps of providing
a deployment catheter, having an elongate flexible body with a
proximal end and a distal end, a control on the proximal end and a
device removably carried by the distal end. At least a portion of
the device is positioned within the left atrial appendage, and the
control is manipulated to enlarge the device under positive
force.
[0013] In one application of the invention, the manipulating step
comprises rotating the control. In general, the device comprises an
expandable frame having at least two and preferably at least about
six spokes. Each spoke is movable from an axial orientation when
the device is in a reduced cross section to an inclined orientation
when the device is in an enlarged cross section.
[0014] In accordance with a further aspect of the present
invention, there is provided a method of removing a device having
tissue anchors thereon, from a site in the body. The method
comprises the steps of positioning a retrieval catheter with
respect to the device such that the anchors are within a flared
distal end on the retrieval catheter. The diameter of the flared
distal end is reduced, with the anchors therein. The retrieval
catheter is thereafter removed from the site. In one aspect of the
method, the reducing step comprises positioning the flared distal
end within an outer tubular sleeve.
[0015] In accordance with a further aspect of the present
invention, there is provided a retrieval catheter for retrieving a
device from an implantation site within the body. The retrieval
catheter comprises an elongate flexible body, having a proximal end
and a distal end. A grasping structure is provided on or carried
within the flexible body, for grasping the device, and a flared
tubular sleeve is provided for surrounding at least a portion of
the device. An outer tubular sleeve, for surrounding the flared
tubular sleeve is also provided. The flared tubular sleeve in one
embodiment comprises a plurality of petals, which are movable
between an axial orientation and an inclined orientation.
[0016] Further features and advantages of the present invention
will become apparent to those of ordinary skill in the art in view
of the detailed description of preferred embodiments which follows,
when considered together with the attached drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective view of an occlusion device in
accordance with the present invention.
[0018] FIG. 2 is a side elevational view of the occlusion device
shown in FIG. 1.
[0019] FIG. 3 is a perspective view of an alternate embodiment of
the present invention.
[0020] FIG. 4 is a side elevational view of the embodiment shown in
FIG. 3.
[0021] FIG. 5 is a perspective view of a further embodiment of the
present invention.
[0022] FIG. 6 is a side elevational view of the embodiment of FIG.
5.
[0023] FIG. 7 is a perspective view of a support structure for a
further occlusion device in accordance with the present
invention.
[0024] FIG. 7A is a side elevational view of the device of FIG.
7.
[0025] FIG. 7B is an end view taken along the line 7B-7B of FIG.
7A.
[0026] FIG. 8 is a schematic illustration of an inflatable balloon
positioned within the occlusion device of FIG. 7.
[0027] FIG. 9 is a schematic view of a pull string deployment
embodiment of the occlusion device of FIG. 7.
[0028] FIGS. 10 and 11 are side elevational schematic
representations of partial and complete barrier layers on the
occlusion device of FIG. 7.
[0029] FIG. 12 is a side elevational schematic view of an alternate
occlusion device in accordance with the present invention.
[0030] FIG. 13 is a schematic view of a bonding layer mesh for use
in forming a composite barrier membrane in accordance with the
present invention.
[0031] FIG. 14 is an exploded cross sectional view of the
components of a composite barrier member in accordance with the
present invention.
[0032] FIG. 15 is a cross sectional view through a composite
barrier formed from the components illustrated in FIG. 14.
[0033] FIG. 16 is a top plan view of the composite barrier
illustrated in FIG. 15.
[0034] FIG. 17 is a schematic view of a deployment system in
accordance with the present invention.
[0035] FIG. 17A is an enlarged view of a releasable lock in an
engaged configuration.
[0036] FIG. 17B is an enlarged view as in FIG. 17A, with the core
axially retracted to release the implant.
[0037] FIG. 18 is a perspective view of a flexible guide tube for
use in the configurations of FIG. 17 and/or FIG. 19.
[0038] FIG. 19 is a schematic view of an alternate deployment
system in accordance with the present invention.
[0039] FIGS. 19A-19B illustrate a removal sequence for an implanted
device in accordance with the present invention.
[0040] FIG. 20 is a schematic cross sectional view through the
distal end of a retrieval catheter having an occlusion device
removably connected thereto.
[0041] FIG. 20A is a side elevational schematic view of the system
illustrated in FIG. 20, with the occlusion device axially elongated
and radially reduced.
[0042] FIG. 20B is a side elevational schematic view as in FIG.
20A, with the occlusion device drawn part way into the delivery
catheter.
[0043] FIG. 20C is a schematic view as in FIG. 20B, with the
occlusion device and delivery catheter drawn into a transeptal
sheath.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0044] Referring to FIGS. 1 and 2, there is illustrated one
embodiment of the occlusion device 10 in accordance with the
present invention. Although the present invention will be described
primarily in the context of an occlusion device, the present
inventors also contemplate omitting the fabric cover or enlarging
the pore size to produce implantable filters or other devices which
are enlargeable at a remote implantation site.
[0045] The occlusion device 10 comprises an occluding member 11
comprising a frame 14 and a barrier 15. In the illustrated
embodiment, the frame 14 comprises a plurality of radially
outwardly extending spokes 17 each having a length within the range
of from about 0.5 cm to about 2 cm from a hub 16. In one
embodiment, the spokes have an axial length of about 1.5 cm.
Depending upon the desired introduction crossing profile of the
collapsed occlusion device 10, as well as structural strength
requirements in the deployed device, anywhere within the range of
from about 3 spokes to about 40 spokes may be utilized. In some
embodiments, anywhere from about 12 to about 24 spokes are
utilized, and, 18 spokes are utilized in one embodiment.
[0046] The spokes are advanceable from a generally axially
extending orientation such as to fit within a tubular introduction
catheter to a radially inclined orientation as illustrated in FIG.
1 and FIG. 2 following deployment from the catheter. In a
self-expandable embodiment, the spokes are biased radially
outwardly such that the occlusion member expands to its enlarged,
implantation cross-section under its own bias following deployment
from the catheter. Alternatively, the occlusion member may be
enlarged using any of a variety of enlargement structures such as
an inflatable balloon, or a catheter for axially shortening the
occlusion member, as is discussed further below.
[0047] Preferably, the spokes comprise a metal such as stainless
steel, Nitinol, Elgiloy, or others which can be determined through
routine experimentation by those of skill in the art. Wires having
a circular or rectangular cross-section may be utilized depending
upon the manufacturing technique. In one embodiment, rectangular
cross section spokes are cut such as by known laser cutting
techniques from tube stock, a portion of which forms the hub
16.
[0048] The barrier 15 may comprise any of a variety of materials
which facilitate cellular in-growth, such as ePTFE. The suitability
of alternate materials for barrier 15 can be determined through
routine experimentation by those of skill in the art. The barrier
15 may be provided on either one or both axially facing sides of
the occlusion member. In one embodiment, the barrier 15 comprises
two layers, with one layer on each side of the frame 14. The two
layers may be bonded to each other around the spokes 17 in any of a
variety of ways, such as by heat bonding with or without an
intermediate bonding layer such as polyethylene or FEP, adhesives,
sutures, and other techniques which will be apparent to those of
skill in the art in view of the disclosure herein. The barrier 15
preferably has a thickness of no more than about 0.003'' and a
porosity within the range of from about 5 .mu.m to about 60
.mu.m.
[0049] The barrier 15 in one embodiment preferably is securely
attached to the frame 14 and retains a sufficient porosity to
facilitate cellular ingrowth and/or attachment. One method of
manufacturing a suitable composite membrane barrier 15 is
illustrated in FIGS. 13-16. As illustrated schematically in FIG.
13, a bonding layer 254 preferably comprises a mesh or other porous
structure having an open surface area within the range of from
about 10% to about 90%. Preferably, the open surface area of the
mesh is within the range of from about 30% to about 60%. The
opening or pore size of the bonding layer 254 is preferably within
the range of from about 0.005 inches to about 0.050 inches, and, in
one embodiment, is about 0.020 inches. The thickness of the bonding
layer 254 can be varied widely, and is generally within the range
of from about 0.0005 inches to about 0.005 inches. In a preferred
embodiment, the bonding layer 254 has a thickness of about 0.001 to
about 0.002 inches. One suitable polyethylene bonding mesh is
available from Smith and Nephew, under the code SN9.
[0050] Referring to FIG. 14, the bonding layer 254 is preferably
placed adjacent one or both sides of a spoke or other frame element
14. The bonding layer 254 and frame 14 layers are then positioned
in-between a first membrane 250 and a second membrane 252 to
provide a composite membrane stack. The first membrane 250 and
second membrane 252 may comprise any of a variety of materials and
thicknesses, depending upon the desired functional result.
Generally, the membrane has a thickness within the range of from
about 0.0005 inches to about 0.010 inches. In one embodiment, the
membranes 250 and 252 each have a thickness on the order of from
about 0.001 inches to about 0.002 inches, and comprise porous
ePTFE, having a porosity within the range of from about 10 microns
to about 100 microns.
[0051] The composite stack is heated to a temperature of from about
200.degree. to about 300.degree., for about 1 minute to about 5
minutes under pressure to provide a finished composite membrane
assembly with an embedded frame 14 as illustrated schematically in
FIG. 15. The final composite membrane has a thickness within the
range of from about 0.001 inches to about 0.010 inches, and,
preferably, is about 0.002 to about 0.003 inches in thickness.
However, the thicknesses and process parameters of the foregoing
may be varied considerably, depending upon the materials of the
bonding layer 254 the first layer 250 and the second layer 252.
[0052] As illustrated in top plan view in FIG. 16, the resulting
finished composite membrane has a plurality of "unbonded" windows
or areas 256 suitable for cellular attachment and/or ingrowth. The
attachment areas 256 are bounded by the frame 14 struts, and the
cross-hatch or other wall pattern formed by the bonding layer 254.
Preferably, a regular window 256 pattern is produced in the bonding
layer 254.
[0053] The foregoing procedure allows the bonding mesh to flow into
the first and second membranes 250 and 252 and gives the composite
membrane 15 greater strength (both tensile and tear strength) than
the components without the bonding mesh. The composite allows
uniform bonding while maintaining porosity of the membrane 15, to
facilitate tissue attachment. By flowing the thermoplastic bonding
layer into the pores of the outer mesh layers 250 and 252, the
composite flexibility is preserved and the overall composite layer
thickness can be minimized.
[0054] Referring back to FIGS. 1 and 2, the occlusion device 10 may
be further provided with a bulking element or stabilizer 194. The
stabilizer 194 may be spaced apart along an axis from the occluding
member 11. In the illustrated embodiment, a distal end 190 and a
proximal end 192 are identified for reference. The designation
proximal or distal is not intended to indicate any particular
anatomical orientation or deployment orientation within the
deployment catheter. As shown in FIGS. 1 and 2, the stabilizer 194
is spaced distally apart from the occluding member 11.
[0055] For use in the LAA, the occluding member 11 has an expanded
diameter within the range of from about 1 cm to about 5 cm, and, in
one embodiment, about 3 cm. The axial length of the occluding
member 11 in an expanded, unstressed orientation from the distal
end 192 to the hub 16 is on the order of about 1 cm. The overall
length of the occlusion device 10 from the distal end 192 to the
proximal end 190 is within the range of from about 1.5 cm to about
4 cm and, in one embodiment, about 2.5 cm. The axial length of the
stabilizer 194 between distal hub 191 and proximal hub 16 is within
the range of from about 0.5 cm to about 2 cm, and, in one
embodiment, about 1 cm. The expanded diameter of the stabilizer 194
is within the range of from about 0.5 cm to about 2.5 cm, and, in
one embodiment, about 1.4 cm. The outside diameter of the distal
hub 191 and proximal hub 16 is about 2.5 mm.
[0056] Preferably, the occlusion device 10 is provided with one or
more retention structures for retaining the device in the left
atrial appendage or other body cavity or lumen. In the illustrated
embodiment, a plurality of barbs or other anchors 195 are provided,
for engaging adjacent tissue to retain the occlusion device 10 in
its implanted position and to limit relative movement between the
tissue and the occlusion device. The illustrated anchors are
provided on one or more of the spokes 17, or other portion of frame
14. Preferably, every spoke, every second spoke or every third
spoke are provided with one or two or more anchors each.
[0057] The illustrated anchor is in the form of a barb, with one on
each spoke for extending into tissue at or near the opening of the
LAA. Depending upon the embodiment, two or three barbs may
alternatively be desired on each spoke. In the single barb
embodiment of FIG. 7, each barb is inclined in a proximal
direction. This is to inhibit proximal migration of the implant out
of the left atrial appendage. In this context, distal refers to the
direction into the left atrial appendage, and proximal refers to
the direction from the left atrial appendage into the heart.
[0058] Alternatively, one or more barbs may face distally, to
inhibit distal migration of the occlusion device deeper into the
LAA. Thus the implant may be provided with at least one proximally
facing barb and at least one distally facing barb. For example, in
an embodiment of the type illustrated in FIG. 12, discussed below,
a proximal plurality of barbs may be inclined in a first direction,
and a distal plurality of barbs may be inclined in a second
direction, to anchor the implant against both proximal and distal
migration.
[0059] One or more anchors 195 may also be provided on the
stabilizer 194, such that it assists not only in orienting the
occlusion device 10 and resisting compression of the LAA, but also
in retaining the occlusion device 10 within the LAA. Any of a wide
variety of structures may be utilized for anchor 195, either on the
occluding member 11 or the stabilizer 194 or both, such as hooks,
barbs, pins, sutures, adhesives, ingrowth surfaces and others which
will be apparent to those of skill in the art in view of the
disclosure herein.
[0060] In use, the occlusion device 10 is preferably positioned
within a tubular anatomical structure to be occluded such as the
left atrial appendage. In a left atrial appendage application, the
occluding member 11 is positioned across or near the opening to the
LAA and the stabilizer 194 is positioned within the LAA. The
stabilizer 194 assists in the proper location and orientation of
the occluding member 11, as well as resists compression of the LAA
behind the occluding member 11. The present inventors have
determined that following deployment of an occluding member 11
without a stabilizer 194 or other bulking structure to resist
compression of the LAA, normal operation of the heart may cause
compression and resulting volume changes in the LAA, thereby
forcing fluid past the occluding member 11 and inhibiting or
preventing a complete seal. Provision of a stabilizer 194
dimensioned to prevent the collapse or pumping of the LAA thus
minimizes leakage, and provision of the barbs facilitates
endothelialization or other cell growth across the occluding member
11.
[0061] The stabilizer 194 is preferably movable between a reduced
cross-sectional profile for transluminal advancement into the left
atrial appendage, and an enlarged cross-sectional orientation as
illustrated to fill or to substantially fill a cross-section
through the LAA. The stabilizing member may enlarge to a greater
cross section than the (pre-stretched) anatomical cavity, to ensure
a tight fit and minimize the likelihood of compression. One
convenient construction includes a plurality of elements 196 which
are radially outwardly expandable in response to axial compression
of a distal hub 191 towards a proximal hub 16. Elements 196 each
comprise a distal segment 198 and a proximal segment 202 connected
by a bend 200. The elements 196 may be provided with a bias in the
direction of the radially enlarged orientation as illustrated in
FIG. 2, or may be radially expanded by applying an expansion force
such as an axially compressive force between distal hub 191 and
proximal hub 16 or a radial expansion force such as might be
applied by an inflatable balloon. Elements 196 may conveniently be
formed by laser cutting the same tube stock as utilized to
construct the distal hub 191, proximal hub 16 and frame 14, as will
be apparent to those of skill in the art in view of the disclosure
herein. Alternatively, the various components of the occlusion
device 10 may be separately fabricated or fabricated in
subassemblies and secured together during manufacturing.
[0062] As a post implantation step for any of the occlusion devices
disclosed herein, a radiopaque dye or other visualizable media may
be introduced on one side or the other of the occlusion device, to
permit visualization of any escaped blood or other fluid past the
occlusion device. For example, in the context of a left atrial
appendage application, the occlusion device may be provided with a
central lumen or other capillary tube or aperture which permits
introduction of a visualizable dye from the deployment catheter
through the occlusion device and into the entrapped space on the
distal side of the occlusion device. Alternatively, dye may be
introduced into the entrapped space distal to the occlusion device
such as by advancing a small gauge needle from the deployment
catheter through the barrier 15 on the occlusion device, to
introduce dye.
[0063] Modifications to the occlusion device 10 are illustrated in
FIGS. 3-4. The occlusion device 10 comprises an occlusion member 11
and a stabilizing member 194 as previously discussed. In the
present embodiment, however, each of the distal segments 198
inclines radially outwardly in the proximal direction and
terminates in a proximal end 204. The proximal end 204 may be
provided with an atraumatic configuration, for pressing against,
but not penetrating, the wall of the left atrial appendage or other
tubular body structure. Three or more distal segments 198 are
preferably provided, and generally anywhere within the range of
from about 6 to about 20 distal segments 198 may be used. In one
embodiment, 9 distal segments 198 are provided. In this embodiment,
three of the distal segments 198 have an axial length of about 5
mm, and 6 of the distal segments 198 have an axial length of about
1 cm. Staggering the lengths of the distal segments 198 may axially
elongate the zone in the left atrial appendage against which the
proximal ends 204 provide anchoring support for the occlusion
device.
[0064] The occlusion device 10 illustrated in FIGS. 3 and 4 is
additionally provided with a hinge 206 to allow the longitudinal
axis of the occlusion member 11 to be angularly oriented with
respect to the longitudinal axis of the stabilizing member 194. In
the illustrated embodiment, the hinge 206 is a helical coil,
although any of a variety of hinge structures can be utilized. The
illustrated embodiment may be conveniently formed by laser cutting
a helical slot through a section of the tube from which the
principal structural components of the occlusion device 10 are
formed. At the distal end of the hinge 206, an annular band 208
connects the hinge 206 to a plurality of axially extending struts
210. In the illustrated embodiment, three axial struts 210 are
provided, spaced equilaterally around the circumference of the
body. Axial struts 210 may be formed from a portion of the wall of
the original tube stock, which portion is left in its original
axial orientation following formation of the distal segments 198
such as by laser cutting from the tubular wall.
[0065] The occlusion member 11 is provided with a proximal zone 212
on each of the spokes 17. Proximal zone 212 has an enhanced degree
of flexibility, to accommodate the fit between the occlusion member
11 and the wall of the left atrial appendage. Proximal section 212
may be formed by reducing the cross sectional area of each of the
spokes 17, which may be provided with a wave pattern as
illustrated.
[0066] Each of the spokes 17 terminates in a proximal point 214.
Proximal point 214 may be contained within layers of the barrier
15, or may extend through or beyond the barrier 15 such as to
engage adjacent tissue and assist in retaining the occlusion device
10 at the deployment site.
[0067] Referring to FIGS. 5 and 6, a further variation on the
occlusion device 10 illustrated in FIGS. 1 and 2 is provided. The
occlusion device 10 is provided with a proximal face 216 on the
occlusion member 11, instead of the open and proximally concave
face on the embodiment of FIGS. 1 and 2. The proximal face 216 is
formed by providing a proximal spoke 218 which connects at an apex
220 to some or all of the distal spokes 17. The proximal spoke 218,
and corresponding apex 220 and distal spoke 17 may be an integral
structure, such as a single ribbon or wire, or element cut from a
tube stock as has been discussed.
[0068] Proximal spokes 218 are each attached to a hub 222 at the
proximal end 192 of the occlusion device 10. The barrier 15 may
surround either the proximal face or the distal face or both on the
occlusion member 11. In general, provision of a proximal spoke 218
connected by an apex 220 to a distal spoke 17 provides a greater
radial force than a distal spoke 17 alone, which will provide an
increased resistance to compression if the occlusion member 11 is
positioned with the LAA.
[0069] Referring to FIGS. 7-12, alternate structures of the
occlusion device in accordance with the present invention are
illustrated. In general, the occlusion device 10 comprises an
occluding member but does not include a distinct stabilizing member
as has been illustrated in connection with previous embodiments.
Any of the embodiments previously disclosed herein may also be
constructed using the occluding member only, and omitting the
stabilizing member as will be apparent to those of skill in the art
in view of the disclosure herein.
[0070] The occluding device 10 comprises a proximal end 192, a
distal end 190, and a longitudinal axis extending therebetween. A
plurality of supports 228 extend between a proximal hub 222 and a
distal hub 191. At least two or three supports 228 are provided,
and preferably at least about ten. In one embodiment, sixteen
supports 228 are provided. However, the precise number of supports
228 can be modified, depending upon the desired physical properties
of the occlusion device 10 as will be apparent to those of skill in
the art in view of the disclosure herein, without departing from
the present invention.
[0071] Each support 228 comprises a proximal spoke portion 218, a
distal spoke portion 17, and an apex 220 as has been discussed.
Each of the proximal spoke portion 218, distal spoke portion 17 and
apex 220 may be a region on an integral support 228, such as a
continuous rib or frame member which extends in a generally curved
configuration as illustrated with a concavity facing towards the
longitudinal axis of the occlusion device 10. Thus, no distinct
point or hinge at apex 220 is necessarily provided.
[0072] At least some of the supports 228, and, preferably, each
support 228, is provided with one or two or more barbs 195. In the
illustrated configuration, the occlusion device 10 is in its
enlarged orientation, such as for occluding a left atrial appendage
or other body cavity or lumen. In this orientation, each of the
barbs 195 projects generally radially outwardly from the
longitudinal axis, and is inclined in the proximal direction. One
or more barbs may also be inclined distally, as is discussed
elsewhere herein. In an embodiment where the barbs 195 and
corresponding support 228 are cut from a single ribbon, sheet or
tube stock, the barb 195 will incline radially outwardly at
approximately a tangent to the curve formed by the support 228.
[0073] The occlusion device 10 constructed from the frame
illustrated in FIG. 7 may be constructed in any of a variety of
ways, as will become apparent to those of skill in the art in view
of the disclosure herein. In one method, the occlusion device 10 is
constructed by laser cutting a piece of tube stock to provide a
plurality of axially extending slots in-between adjacent supports
228. Similarly, each barb 195 can be laser cut from the
corresponding support 228 or space in-between adjacent supports
228. The generally axially extending slots which separate adjacent
supports 228 end a sufficient distance from each of the proximal
end 192 and distal end 190 to leave a proximal hub 222 and a distal
hub 191 to which each of the supports 228 will attach. In this
manner, an integral cage structure may be formed. Alternatively,
each of the components of the cage structure may be separately
formed and attached together such as through soldering, brazing,
heat bonding, adhesives, and other fastening techniques which are
known in the art. A further method of manufacturing the occlusion
device 10 is to laser cut a slot pattern on a flat sheet of
appropriate material, such as a flexible metal or polymer, as has
been discussed in connection with previous embodiments. The flat
sheet may thereafter be rolled about an axis and opposing edges
bonded together to form a tubular structure.
[0074] The apex portion 220 which carries the barb 195 may be
advanced from a low profile orientation in which each of the
supports 228 extend generally parallel to the longitudinal axis, to
an implanted orientation as illustrated, in which the apex 220 and
the barb 195 are positioned radially outwardly from the
longitudinal axis. The support 228 may be biased towards the
enlarged orientation, or may be advanced to the enlarged
orientation under positive force following positioning within the
tubular anatomical structure, in any of a variety of manners.
[0075] For an example of enlarging under positive force, referring
to FIG. 8, an inflatable balloon 230 is positioned within the
occlusion device 10. Inflatable balloon 230 is connected by way of
a removable coupling 232 to an inflation catheter 234. Inflation
catheter 234 is provided with an inflation lumen for providing
communication between an inflation media source 236 outside of the
patient and the balloon 230. Following positioning within the
target body lumen, the balloon 230 is inflated, thereby engaging
barbs 195 with the surrounding tissue. The inflation catheter 234
is thereafter removed, by decoupling the removable coupling 232,
and the inflation catheter 234 is thereafter removed. The balloon
230 may be either left in place within the occlusion device 10, or
deflated and removed by the inflation catheter 234.
[0076] In an alternate embodiment, the supports 228 are radially
enlarged such as through the use of a deployment catheter 238. See
FIG. 9. Deployment catheter 238 comprises a lumen for movably
receiving a deployment element such as a flexible line 240.
Deployment line 240 extends in a loop 244 formed by an aperture or
slip knot 242. As will be apparent from FIG. 9, proximal refraction
on the deployment line 240 while resisting proximal movement of
proximal hub 222 such as by using the distal end of the catheter
238 will cause the distal hub 191 to be drawn towards the proximal
hub 222, thereby radially enlarging the cross-sectional area of the
occlusion device 10. Depending upon the material utilized for the
occlusion device 10, the supports 228 will retain the radially
enlarged orientation by elastic deformation, or may be retained in
the enlarged orientation such as by securing the slip knot 242
immovably to the deployment line 240 at the fully radially enlarged
orientation. This may be accomplished in any of a variety of ways,
using additional knots, clips, adhesives, or other techniques known
in the art.
[0077] A variety of alternative structures may be utilized, to open
or enlarge the occlusion device 10 under positive force. For
example, Referring to FIG. 9, a pullwire 240 may be removably
attached to the distal hub 191 or other distal point of attachment
on the occlusion device 10. Proximal retraction of the pullwire 240
while resisting proximal motion of the proximal hub 222 such as by
using the distal end of the catheter 238 will cause enlargement of
the occlusion device 10 as has been discussed. The pullwire 240 may
then be locked with respect to the proximal hub 222 and severed or
otherwise detached to enable removal of the deployment catheter 238
and proximal extension of the pullwire 240. Locking of the pullwire
with respect to the proximal hub 222 may be accomplished in any of
a variety of ways, such as by using interference fit or friction
fit structures, adhesives, a knot or other technique depending upon
the desired catheter design.
[0078] Referring to FIGS. 10 and 11, the occlusion device 10 may be
provided with a barrier 15 such as a mesh or fabric as has been
previously discussed. Barrier 15 may be provided on only one
hemisphere such as proximal face 216, or may be carried by the
entire occlusion device 10 from proximal end 192 to distal end 190.
The barrier may be secured to the radially inwardly facing surface
of the supports 228, as illustrated in FIG. 11, or may be provided
on the radially outwardly facing surfaces of supports 228, or
both.
[0079] A further embodiment of the occlusion device 10 is
illustrated in FIG. 12, in which the apex 220 is elongated in an
axial direction to provide additional contact area between the
occlusion device 10 and the wall of the tubular structure. In this
embodiment, one or two or three or more anchors 195 may be provided
on each support 228, depending upon the desired clinical
performance. The occlusion device 10 illustrated in FIG. 12 may
also be provided with any of a variety of other features discussed
herein, such as a partial or complete barrier 15. In addition, the
occlusion device 10 illustrated in FIG. 12 may be enlarged using
any of the techniques disclosed elsewhere herein.
[0080] Referring to FIG. 17, there is schematically illustrated a
further aspect of the present invention. An adjustable implant
deployment system 300 comprises generally a catheter 302 for
placing a detachable implant 304 within a body cavity or lumen, as
has been discussed. The catheter 302 comprises an elongate flexible
tubular body 306, extending between a proximal end 308 and a distal
end 310. The catheter is shown in highly schematic form, for the
purpose of illustrating the functional aspects thereof. The
catheter body will have a sufficient length and diameter to permit
percutaneous entry into the vascular system, and transluminal
advancement through the vascular system to the desired deployment
site. For example, in an embodiment intended for access at the
femoral artery and deployment within the left atrial appendage, the
catheter 302 will have a length within the range of from about 50
cm to about 150 cm, and a diameter of generally no more than about
15 French. Further dimensions and physical characteristics of
catheters for navigation to particular sites within the body are
well understood in the art and will not be further described
herein.
[0081] The tubular body 306 is further provided with a handle 309
generally on the proximal end 308 of the catheter 302. The handle
309 permits manipulation of the various aspects of the implant
deployment system 300, as will be discussed below. Handle 309 may
be manufactured in any of a variety of ways, typically by injection
molding or otherwise forming a handpiece for single-hand operation,
using materials and construction techniques well known in the
medical device arts.
[0082] The implant 304 may be in the form of any of those described
previously herein, as modified below. In general, the implant is
movable from a reduced crossing profile to an enlarged crossing
profile, such that it may be positioned within a body structure and
advanced from its reduced to its enlarged crossing profile to
obstruct bloodflow or perform other functions while anchored
therein. The implant 304 may be biased in the direction of the
enlarged crossing profile, may be neutrally biased or may be biased
in the direction of the reduced crossing profile. Any modifications
to the device and deployment system to accommodate these various
aspects of the implant 304 may be readily accomplished by those of
skill in the art in view of the disclosure herein.
[0083] In the illustrated embodiment, the distal end 314 of the
implant 304 is provided with an implant plug 316. Implant plug 316
provides a stopping surface 317 for contacting an axially movable
core 312. The core 312 extends axially throughout the length of the
catheter body 302, and is attached at its proximal end to a core
control 332 on the handle 309.
[0084] The core 312 may comprise any of a variety of structures
which has sufficient lateral flexibility to permit navigation of
the vascular system, and sufficient axial column strength to enable
reduction of the implant 304 to its reduced crossing profile. Any
of a variety of structures such as hypotube, solid core wire,
"bottomed out" coil spring structures, or combinations thereof may
be used, depending upon the desired performance of the finished
device. In one embodiment, the core 312 comprises stainless steel
tubing.
[0085] The distal end of core 312 is positioned within a recess or
lumen 322 defined by a proximally extending guide tube 320. In the
illustrated embodiment, the guide tube 320 is a section of tubing
such as metal hypotube, which is attached at the distal end 314 of
the implant and extends proximally within the implant 304. The
guide tube 320 preferably extends a sufficient distance in the
proximal direction to inhibit buckling or prolapse of the core 312
when distal pressure is applied to the core control 332 to reduce
the profile of the implant 304. However, the guide tube 320 should
not extend proximally a sufficient distance to interfere with the
opening of the implant 304.
[0086] As will be appreciated by reference to FIG. 17, the guide
tube 320 may operate as a limit on distal axial advancement of the
proximal end 324 of implant 304. Thus, the guide tube 320
preferably does not extend sufficiently far proximally from the
distal end 314 to interfere with optimal opening of the implant
304. The specific dimensions are therefore relative, and will be
optimized to suit a particular intended application. In one
embodiment, the implant 304 has an implanted outside diameter
within the range of from about 5 mm to about 45 mm, and an axial
implanted length within the range of from about 5 mm to about 45
mm. The guide tube 320 has an overall length of about 3 mm to about
35 mm, and an outside diameter of about 0.095 inches.
[0087] An alternate guide tube 320 is schematically illustrated in
FIG. 18. In this configuration, the guide tube 320 comprises a
plurality of tubular segments 321 spaced apart by an intervening
space 323. This allows increased flexibility of the guide tube 320,
which may be desirable during the implantation step, while
retaining the ability of the guide tube 320 to maintain linearity
of the core 312 while under axial pressure. Although three segments
321 are illustrated in FIG. 18, as many as 10 or 20 or more
segments 321 may be desirable depending upon the desired
flexibility of the resulting implant.
[0088] Each adjacent pair of segments 321 may be joined by a hinge
element 325 which permits lateral flexibility. In the illustrated
embodiment, the hinge element 325 comprises an axially extending
strip or spine, which provides column strength along a first side
of the guide tube 320. The guide tube 320 may therefore be curved
by compressing a second side of the guide tube 320 which is
generally offset from the spine 325 by about 180.degree. A limit on
the amount of curvature may be set by adjusting the axial length of
the space 323 between adjacent segments 321. In an embodiment
having axial spines 325, each axial spine 325 may be rotationally
offset from the next adjacent axial spine 325 to enable flexibility
of the overall guide tube 320 throughout a 360.degree. angular
range of motion.
[0089] Alternatively, the flexible hinge point between each
adjacent segment 321 may be provided by cutting a spiral groove or
plurality of parallel grooves in a tubular element in between what
will then become each adjacent pair of segments 321. In this
manner, each tubular element 321 will be separated by an integral
spring like structure, which can permit flexibility. As a further
alternative, the entire length of the guide tube 320 may comprise a
spring. Each of the forgoing embodiments may be readily constructed
by laser cutting or other cutting from a piece of tube stock, to
produce a one piece guide tube 320. Alternatively, the guide tube
320 may be assembled from separate components and fabricated
together using any of a variety of bonding techniques which are
appropriate for the construction material selected for the tube
320.
[0090] Various distal end 314 constructions may be utilized, as
will be apparent to those of skill in the art in view of the
disclosure herein. In the illustrated embodiment, the distal
implant plug 316 extends within the implant 304 and is attached to
the distal end of the guide tube 320. The implant plug 316 may be
secured to the guide tube 320 and implant 304 in any of a variety
of ways, depending upon the various construction materials. For
example, any of a variety of metal bonding techniques such as a
welding, brazing, interference fit such as threaded fit or snap
fit, may be utilized. Alternatively, any of a variety of bonding
techniques for dissimilar materials may be utilized, such as
adhesives, and various molding techniques. In one construction, the
implant plug 316 comprises a molded polyethylene cap, and is held
in place utilizing a distal cross pin 318 which extends through the
implant 304, the guide tube 320 and the implant plug 316 to provide
a secure fit against axial displacement.
[0091] The proximal end 324 of the implant 304 is provided with a
releasable lock 326 for attachment to a release element such as
pull wire 328. Pull wire 328 extends proximally throughout the
length of the tubular body 306 to a proximal pull wire control 330
on the handle 309.
[0092] As used herein, the term pull wire is intended to include
any of a wide variety of structures which are capable of
transmitting axial tension or compression such as a pushing or
pulling force with or without rotation from the proximal end 308 to
the distal end 310 of the catheter 302. Thus, monofilament or
multifilament metal or polymeric rods or wires, woven or braided
structures may be utilized. Alternatively, tubular elements such as
a concentric tube positioned within the outer tubular body 306 may
also be used as will be apparent to those of skill in the art.
[0093] In the illustrated embodiment, the pull wire 328 is
releasably connected to the proximal end 324 of the implant 304.
This permits proximal advancement of the proximal end of the
implant 304, which cooperates with a distal retention force
provided by the core 312 against the distal end of the implant to
axially elongate the implant 304 thereby reducing it from its
implanted configuration to its reduced profile for implantation.
The proximal end of the pull wire 328 may be connected to any of a
variety of pull wire controls 330, including rotational knobs,
levers and slider switches, depending upon the design
preference.
[0094] The proximal end 324 of the implant 304 is thus preferably
provided with a releasable lock 326 for attachment of the pullwire
328 to the deployment catheter. In the illustrated embodiment, the
releasable lock is formed by advancing the pullwire distally around
a cross pin 329, and providing an eye or loop which extends around
the core 312. As long as the core 312 is in position within the
implant 304, proximal retraction of the pullwire 328 will advance
the proximal end 324 of the implant 304 in a proximal direction.
See FIG. 17A. However, following deployment, proximal retraction of
the core 312 such as by manipulation of the core control 332 will
pull the distal end of the core 312 through the loop on the distal
end of the pullwire 328. The pullwire 328 may then be freely
proximally removed from the implant 304, thereby enabling
detachment of the implant 304 from the deployment system 300 within
a treatment site. See FIG. 17B.
[0095] The implant. deployment system 300 thus permits the implant
304 to be maintained in a low crossing profile configuration, to
enable transluminal navigation to a deployment site. Following
positioning at or about the desired deployment site, proximal
retraction of the core 312 enables the implant 304 to radially
enlarge under its own bias to fit the surrounding tissue structure.
Alternatively, the implant can be enlarged under positive force,
such as by inflation of a balloon or by a mechanical mechanism as
is discussed elsewhere herein. Once the clinician is satisfied with
the position of the implant 304, such as by injection of dye and
visualization using conventional techniques, the core 312 is
proximally retracted thereby releasing the lock 326 and enabling
detachment of the implant 304 from the deployment system 300.
[0096] If, however, visualization reveals that the implant 304 is
not at the location desired by the clinician, proximal retraction
of the pull wire 328 with respect to the core 312 will radially
reduce the diameter of the implant 304, thereby enabling
repositioning of the implant 304 at the desired site. Thus, the
present invention permits the implant 304 to be enlarged or reduced
by the clinician to permit repositioning and/or removal of the
implant 304 as may be desired.
[0097] In an alternate construction, the implant may be radially
enlarged or reduced by rotating a torque element extending
throughout the deployment catheter. Referring to FIG. 19, the
elongate flexible tubular body 306 of the deployment catheter 302
includes a rotatable torque rod 340 extending axially therethrough.
The proximal end of the torque rod 340 may be connected at a
proximal manifold to a manual rotation device such as a hand crank,
thumb wheel, rotatable knob or the like. Alternatively, the torque
rod 340 may be connected to a power driven source of rotational
energy such as a motor drive or air turbine.
[0098] The distal end of the torque rod 340 is integral with or is
connected to a rotatable core 342 which extends axially through the
implant 304. A distal end 344 of the rotatable core 342 is
positioned within a cavity 322 as has been discussed.
[0099] The terms torque rod or torque element are intended to
include any of a wide variety of structures which are capable of
transmitting a rotational torque throughout the length of a
catheter body. For example, solid core elements such as stainless
steel, nitinol or other nickel titanium alloys, or polymeric
materials may be utilized. In an embodiment intended for
implantation over a guide-wire, the torque rod 340 is preferably
provided with an axially extending central guidewire lumen. This
may be accomplished by constructing the torque rod 340 from a
section of hypodermic needle tubing, having an inside diameter of
from about 0.001 inches to about 0.005 inches or more greater than
the outside diameter of the intended guidewire. Tubular torque rods
340 may also be fabricated or constructed utilizing any of a wide
variety of polymeric constructions which include woven or braided
reinforcing layers in the wall. Torque transmitting tubes and their
methods of construction are well understood in the intracranial
access and rotational atherectomy catheter arts, among others, and
are not described in greater detail herein. Use of a tubular torque
rod 340 also provides a convenient infusion lumen for injection of
contrast media within the implant 304, such as through a port
343.
[0100] The proximal end 324 of the implant 304 is provided with a
threaded aperture 346 through which the core 342 is threadably
engaged. As will be appreciated by those of skill in the art in
view of the disclosure herein, rotation of the threaded core 342 in
a first direction relative to the proximal end 324 of the implant
304 will cause the rotatable core 342 to advance distally. This
distal advancement will result in an axial elongation and radial
reduction of the implantable device 304. Rotation of the rotatable
core 342 in a reverse direction will cause a proximal refraction of
the rotatable core 342, thus enabling a radial enlargement and
axial shortening of the implantable device 304.
[0101] The deployment catheter 302 is further provided with an
antirotation lock 348 between a distal end 350 of the tubular body
306 and the proximal end 324 of the implant 304. In general, the
rotational lock 348 may be conveniently provided by cooperation
between a first surface 352 on the distal end 350 of the deployment
catheter 302, which engages a second surface 354 on the proximal
end 324 of the implantable device 304, to rotationally link the
deployment catheter 302 and the implantable device 304. Any of a
variety of complementary surface structures may be provided, such
as an axial extension on one of the first and second surfaces for
coupling with a corresponding recess on the other of the first and
second surfaces. Such extensions and recesses may be positioned
laterally offset from the axis of the catheter. Alternatively, they
may be provided on the longitudinal axis with any of a variety of
axially releasable anti-rotational couplings having at least one
flat such as a hexagonal or other multifaceted cross sectional
configuration.
[0102] As schematically illustrated in FIG. 19, one or more
projections 356 on the first surface 352 may engage a corresponding
recess 358 on the second surface 354. Any of a variety of
alternative complementary surface structures may also be provided,
as will be apparent to those of skill in the art in view of the
disclosure herein. For example, referring to FIG. 19A, the
projection 356 is in the form of an axially extending pin for
engaging a complimentary recess 358 on the proximal end 324 of the
implant 304. FIG. 19B illustrates an axially extending spline 356
for receipt within a complimentary axially extending recess 358.
The various pin, spline and other structures may be reversed
between the distal end of tubular body 306 and the proximal end 324
of the implant 304 as will be apparent to those of skill in the art
in view of the disclosure herein.
[0103] Upon placement of the implantable device 304 at the desired
implantation site, the torque rod 340 is rotated in a direction
that produces an axial proximal retraction. This allows radial
enlargement of the radially outwardly biased implantable device 304
at the implantation site. Continued rotation of the torque rod 340
will cause the threaded core 342 to exit proximally through the
threaded aperture 346. At that point, the deployment catheter 302
may be proximally retracted from the patient, leaving the implanted
device 304 in place.
[0104] By modification of the decoupling mechanism to allow the
core 342 to be decoupled from the torque rod 340, the rotatable
core 342 may be left within the implantable device 304, as may be
desired depending upon the intended deployment mechanism. For
example, the distal end of the core 342 may be rotatably locked
within the end cap 326, such as by including complimentary radially
outwardly or inwardly extending flanges and grooves on the distal
end of the core 342 and inside surface of the cavity 322. In this
manner, proximal retraction of the core 342 by rotation thereof
relative to the implantable device 304 will pull the end cap 326 in
a proximal direction under positive force. This may be desirable as
a supplement to or instead of a radially enlarging bias built into
the implantable device 304.
[0105] In the embodiment illustrated in FIG. 19, or any other of
the deployment and/or removal catheters described herein, the
distal end of the tubular body 306 may be provided with a zone or
point of enhanced lateral flexibility. This may be desirable in
order allow the implant to seat in the optimal orientation within
the left atrial appendage, and not be restrained by a lack of
flexibility in the tubular body 306. This may be accomplished in
any of a variety of way, such as providing the distal most one or
two or three centimeters or more of the tubular body 306 with a
spring coil configuration. In this manner, the distal end of the
tubular body 306 will be sufficiently flexible to allow the implant
304 to properly seat within the LAA. This distal flex zone on the
tubular body 306 may be provided in any of a variety of ways, such
as by cutting a spiral slot in the distal end of the tubular body
306 using laser cutting or other cutting techniques. The components
within the tubular body 306 such as torque rod 340 may similarly be
provided with a zone of enhanced flexibility in the distal region
of the tubular body 306.
[0106] The implantable device 304 may also be retrieved and removed
from the body in accordance with a further aspect of the present
invention. One manner of retrieval and removal will be understood
in connection with FIGS. 20 through 20c. Referring to FIG. 20, a
previously implanted device 304 is illustrated as releasably
coupled to the distal end of the tubular body 306, as has been
previously discussed. Coupling may be accomplished by aligning the
tubular body 306 with the proximal end 324 of the deployed implant
304, under fluoroscopic visualization, and distally advancing a
rotatable core 342 through the threaded aperture 346. Threadable
engagement between the rotatable core 342 and aperture 346 may
thereafter be achieved, and distal advancement of core 342 will
axially elongate and radially reduce the implant 304.
[0107] The tubular body 306 is axially moveably positioned within
an outer tubular delivery or retrieval catheter 360. Catheter 360
extends from a proximal end (not illustrated) to a distal end 362.
The distal end 362 is preferably provided with a flared opening,
such as by constructing a plurality of petals 364 for facilitating
proximal retraction of the implant 304 as will become apparent.
Petals 364 may be constructed in a variety of ways, such as by
providing axially extending slits in the distal end 362 of the
delivery catheter 360. In this manner, preferably at least about
three, and generally at least about four or five or six petals or
more will be provided on the distal end 362 of the delivery
catheter 360. Petals 364 manufactured in this manner would reside
in a first plane, transverse to the longitudinal axis of the
delivery catheter 360, if each of such petals 364 were inclined at
90 degrees to the longitudinal axis of the delivery catheter
360.
[0108] In one application of the invention, a second layer of
petals 365 are provided, which would lie in a second, adjacent
plane if the petals 365 were inclined at 90 degrees to the
longitudinal axis of the delivery catheter 360. Preferably, the
second plane of petals 365 is rotationally offset from the first
plane of petals 364, such that the second petals 365 cover the
spaces 367 formed between each adjacent pair of petals 365. The use
of two or more layers of staggered petals 364 and 365 has been
found to be useful in retrieving implants 304, particularly when
the implant 304 carries a plurality of tissue anchors 195.
[0109] The petals 364 and 365 may be manufactured from any of a
variety of polymer materials useful in constructing medical device
components such as the delivery catheter 360. This includes, for
example, polyethylene, PET, PEEK, PEBAX, and others well known in
the art. The second petals 365 may be constructed in any of a
variety of ways. In one convenient construction, a section of
tubing which concentrically fits over the delivery catheter 360 is
provided with a plurality of axially extending slots in the same
manner as discussed above. The tubing with a slotted distal end may
be concentrically positioned on the catheter 360, and rotated such
that the space between adjacent petals 365 is offset from the space
between adjacent petals 364. The hub of the petals 365 may
thereafter be bonded to the catheter 360, such as by heat
shrinking, adhesives, or other bonding techniques known in the
art.
[0110] The removal sequence will be further understood by reference
to FIGS. 20a through 20c. Referring to FIG. 20a, the radially
reduced implant 304 is proximally retracted part way into the
delivery catheter 360. This can be accomplished by proximally
retracting the tubular body 306 and/or distally advancing the
catheter 360. As illustrated in FIG. 20b, the tubular body 306
having the implant 304 attached thereto is proximally retracted a
sufficient distance to position the tissue anchors 195 within the
petals 364. The entire assembly of the tubular body 306, within the
delivery catheter 360 may then be proximally retracted within the
transeptal sheath 366 or other tubular body as illustrated in FIG.
20c. The collapsed petals 364 allow this to occur while preventing
engagement of the tissue anchors 195 with the distal end of the
transeptal sheath 366 or body tissue. The entire assembly having
the implantable device 304 contained therein may thereafter be
proximally withdrawn from or repositioned within the patient.
[0111] While particular forms of the invention have been described,
it will be apparent that various modifications can be made without
departing from the spirit and scope of the invention. Accordingly,
it is not intended that the invention be limited, except as by the
appended claims.
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