U.S. patent application number 10/621832 was filed with the patent office on 2004-05-20 for systems, methods and devices for removing obstructions from a blood vessel.
Invention is credited to Dieck, Martin, Gia, Son, Sepetka, Ivan.
Application Number | 20040098025 10/621832 |
Document ID | / |
Family ID | 24422442 |
Filed Date | 2004-05-20 |
United States Patent
Application |
20040098025 |
Kind Code |
A1 |
Sepetka, Ivan ; et
al. |
May 20, 2004 |
Systems, methods and devices for removing obstructions from a blood
vessel
Abstract
A system for removing an obstruction from a blood vessel
includes an obstruction engaging element and an expandable capture
element. The capture element preferably has a flexible cover and an
expandable support structure. The engaging element engages the
obstruction and moves the obstruction into the capture element. The
capture element protects the obstruction when the obstruction is
moved into the catheter.
Inventors: |
Sepetka, Ivan; (Los Altos,
CA) ; Dieck, Martin; (Cupertino, CA) ; Gia,
Son; (San Jose, CA) |
Correspondence
Address: |
HOEKENDIJK & LYNCH, LLP
P.O. BOX 4787
BURLINGAME
CA
94011-4787
US
|
Family ID: |
24422442 |
Appl. No.: |
10/621832 |
Filed: |
July 16, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10621832 |
Jul 16, 2003 |
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09756476 |
Jan 8, 2001 |
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6663650 |
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09756476 |
Jan 8, 2001 |
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09605143 |
Jun 29, 2000 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 2018/00214
20130101; A61B 2017/22034 20130101; A61B 2017/2215 20130101; A61F
2002/018 20130101; A61B 17/22031 20130101; A61F 2002/016 20130101;
A61M 25/0082 20130101; A61F 2230/0091 20130101; A61B 2017/2217
20130101; A61B 17/221 20130101; A61B 2017/2212 20130101; A61M
25/0074 20130101; A61B 18/1492 20130101; A61B 2018/00898 20130101;
A61M 25/008 20130101; A61M 25/0068 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 029/00 |
Claims
What is claimed is:
1. A system for removing an obstruction from a blood vessel,
comprising: a catheter having a lumen; an expandable capture
element which is contained within the lumen of the catheter, the
capture element being slidable within the lumen of the catheter
between a collapsed position contained within the lumen and an
expanded position in which the capture element is positioned
outside the lumen; and an obstruction engaging device having a
filament, the filament being movable from a collapsed position to
an expanded position, the obstruction engaging element passing
through the catheter.
2. The system of claim 1, wherein: the expandable capture element
is naturally biased toward the expanded position when positioned
outside the lumen.
3. The system of claim 3, wherein: the expandable capture element
has a support structure with a flexible cover attached to the
support structure.
4. The system of claim 3, wherein: the self-expanding support
structure has a closed loop having integrally formed hinges.
5. The system of claim 4, wherein: the hinges are V-shaped
interconnecting elements.
6. The system of claim 3, wherein: the support structure has a
plurality of longitudinal struts extending from the loop.
7. The system of claim 1, wherein: the capture element has an
expandable loop at the distal end.
8. The system of claim 7, wherein: the loop is formed by an eyelet
with a control arm extending through the eyelet.
9. The system of claim 1, wherein: the capture element has a
flexible cover, the cover having a length which is at least three
times an expanded diameter of the capture element.
10. The system of claim 9, wherein: the length of the cover is at
least five times the expanded diameter of the capture element.
11. The system of claim 1, wherein: the engaging device has 1-4
filaments.
12. A method of removing an obstruction from a blood vessel
comprising the steps of: providing a catheter, an obstruction
engaging device and an expandable capture element, the capture
element being contained within a lumen of the catheter in a
collapsed position, the capture element moving to an expanded
position when positioned outside the lumen, the obstruction
engaging device having a filament which is movable from a collapsed
position to an expanded position; introducing the catheter into a
blood vessel of a patient; engaging an obstruction with the
filament; expanding the capture element; and moving the obstruction
into the capture element with the engaging device after the
engaging and expanding steps.
13. The method of claim 12, wherein: engaging step is carried out
with the filament penetrating and ensnaring the obstruction.
14. The method of claim 12, wherein: the expanding step is carried
out with the capture element being naturally biased toward the
expanded position with a self-expanding support structure.
15. The method of claim 14, wherein: the providing step is carried
out with a flexible material attached to the support structure.
16. The method of claim 15, wherein: the providing step is carried
out with the self-expanding support structure having a closed
loop.
17. The method of claim 15, wherein: the providing step is carried
out with the loop being integrally formed.
18. The method of claim 15, wherein: the providing step is carried
out with the support structure has a plurality of longitudinal
struts.
19. The method of claim 18, wherein: the providing step is carried
out with the loop being formed by a number of integrally formed
hinges.
20. The method of claim 19, wherein: the providing step is carried
out with the hinges being V-shaped elements.
21. The method of claim 12, wherein: the obstruction engaging
element has 1-4 filaments.
22. A system for removing an obstruction from a blood vessel,
comprising: a catheter having a lumen; an expandable capture
element contained within the lumen of the catheter, the capture
element being in a collapsed position when contained within the
lumen and being in an expanded position when positioned outside the
lumen, the expandable capture element having a support structure
forming a closed loop having a plurality of integrally formed
hinges; and an obstruction engaging device which extends through
the expandable capture element, the engaging device having a
collapsed shape and an expanded shape.
23. The system of claim 22, wherein: the capture element has a
flexible cover attached to the support structure, the cover having
a distal end which is positioned at the loop so that the loop opens
the distal end of the cover.
24. The system of claim 22, wherein: the support structure has a
plurality of longitudinal struts which extend proximally from the
loop.
25. The system of claim 24, wherein: the struts do not intersect
and form a form a conical shape when the capture element is in the
expanded.
26. The system of claim 22, wherein: the loop has integrally formed
hinges.
27. The system of claim 26, wherein: the hinges are formed by
V-shaped elements.
28. The system of claim 22, wherein: the obstruction engaging
device has a filament configured to penetrate and engage an
obstruction.
29. A system for removing an obstruction from a blood vessel,
comprising: a catheter having a lumen: an expandable capture
element which is contained within the lumen of the catheter, the
capture element being slidable within the lumen of the catheter,
the capture element having an actuator for manually expanding and
contracting the capture element; and an obstruction engaging device
which passes through the capture element.
30. The system of claim 29, wherein: the obstruction engaging
devices includes a filament for engaging the obstruction.
31. The system of claim 29, wherein: the actuator has a control arm
and a stable arm, the control arm being manipulated to expand and
collapse the capture element.
32. The system of claim 29, wherein: the actuator has a loop and a
control arm which is manipulated to open and close the loop.
33. The system of claim 29, wherein: the capture element everts
when moving outside the lumen.
34. The system of claim 29, wherein: the actuator includes a tube
and a wire extending through the tube.
35. The system of claim 29, wherein: the actuator includes at least
two wires.
36. The system of claim 35, wherein: the actuator includes first
and second stabilizing wires and at least one actuating wire.
37. A catheter for capturing an obstruction, comprising: a catheter
having a lumen; a capture element positioned in the lumen of the
catheter, the capture element being expandable, the capture element
having an expandable support structure and a cover attached to the
support structure, the cover having a length which is at least
three times a diameter of the support structure in the expanded
position.
38. The catheter of claim 37, wherein: the cover has a length which
is at least five times a diameter of the support structure in the
expanded position.
39. A device for removing an obstruction from a blood vessel,
comprising: an expandable loop which is movable from a collapsed
position to an expanded position; a cover coupled to the loop, the
distal end of the cover being moving from a closed position to an
open position when the loop moves from the collapsed to expanded
positions; and a tube having an actuator extending therethrough,
the actuator being coupled to the loop so that relative movement
between the tube and the actuator causes the loop to move between
the expanded and collapsed positions.
40. The device of claim 39, wherein: the tube is positioned outside
the cover.
41. The device of claim 39, further comprising: a catheter passing
through the cover; and an obstruction engaging device passing
through the catheter.
42. A device for removing an obstruction from a blood vessel,
comprising: a tube; a support structure movable between a collapsed
position and an expanded position, the support structure extending
through the tube and being naturally biased toward the expanded
position, wherein the support structure expands when moved out of
the distal end of the tube and is in the collapsed position when
contained within the tube, the support structure being bowed
outward; a cover coupled to the structure, the cover moving from a
closed position to an open position when the loop moves from the
collapsed position to the expanded position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of
application Ser. No. 09/605,143, filed Jun. 29, 2000, entitled,
"Methods and Devices for Removing an Obstruction From a Blood
Vessel," by inventors Sepetka, et al., the full disclosure of which
is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention is directed to methods and devices for
removing obstructions from blood vessels. The device may be used to
retrieve and remove clots and other biological obstructions. The
device may also be used to retrieve embolic coils and the like
which have been misplaced or have migrated to an undesirable
location.
[0003] One such obstruction removal device is disclosed in U.S.
Pat. No. 5,895,398 which is hereby incorporated by reference. The
device has an expandable engaging member which is introduced into
the blood vessel to engage the obstruction for removal.
[0004] The present invention is also directed to devices, systems
and methods which use an expandable capture element when removing
obstructions from a blood vessel. One such system for removing
obstructions in a blood vessel is described in U.S. Pat. No.
5,102,415 to Guenther et al. The system described in U.S. Pat. No.
5,102,415 has a balloon catheter and a catheter having an
expandable tip which receives the obstruction. The balloon catheter
is passed through the obstruction while the balloon is deflated.
The balloon is then inflated and the tip of the catheter is
expanded. The balloon is then moved proximally so that the
obstruction is pulled into the expanded tip of the catheter. A
problem with the system of U.S. Pat. No. 5,102,415 is that the
interaction between the balloon catheter and the leading edge of
the catheter may tend to shear off portions of the obstruction.
This can cause obvious problems when working in sensitive vascular
areas.
[0005] The present invention is directed to additional devices and
methods for removing obstructions in a blood vessel.
SUMMARY OF THE INVENTION
[0006] In accordance with the present invention, device and methods
for removing obstructions are provided. In a first aspect of the
invention, an obstruction removal device is provided which has an
obstruction engaging element extending from an insertion element.
The engaging element is movable from a collapse position to an
expanded position. The engaging element forms coils having varying
diameter wherein the coils at a distal portion are larger than
coils at an intermediate portion. The distal portion forms a
relatively closed structure which prevents the obstruction, or any
part thereof, from migrating downstream. The distal portion is
expanded distal to the obstruction while the proximal portion
engages to and holds the obstruction.
[0007] In another aspect of the present invention, another
obstruction removal device is provided which has at least one
closed loop and preferably two closed loops. The closed loop
provides an advantage when advanced through a catheter or sheath in
that the closed loop produces opposing radial forces on the
catheter or sheath through which the loop is advanced. In this
manner, the obstruction removal device can be advanced more easily
through the catheter or sheath to prevent binding or kinking of the
device during advancement. In a preferred embodiment, the
obstruction removal device has two loops of varying diameter with
the distal loop having a larger diameter. Each of the loops lie in
a plane with the planes of the two loops preferably being
perpendicular to one another.
[0008] In another aspect of the invention, another obstruction
removal device is provided which has wound sections formed by one
or more filaments which are separated by sections substantially
free of the filaments. The intermittent wound sections provide
discrete portions where the obstruction can be engaged. In an
embodiment, the wound sections can slide on the core element to
provide flexibility when advancing the obstruction removal device.
The wound sections and sections free of filament are preferably
about 1-5 mm long. The obstruction removal device preferably has at
least three wound sections and more preferably at least five wound
sections.
[0009] In still another aspect of the invention, another
obstruction removal device is provided which has alternating large
and small diameter portions. In a preferred embodiment, the
obstruction removal device has at least four large diameter
sections and three smaller diameter portions. The alternating large
and small diameter portions may help to engage certain types of
obstructions and can also help to prevent parts of the obstruction
from breaking off and migrating downstream.
[0010] Any of the obstruction removal devices described herein may
also be used with a source of power coupled to the obstruction
removal device for use as described below. The source of power may
simply produce a positive or negative charge or may be an RF energy
source. The source of power may be used to help the obstruction
removal device penetrate and engage the obstruction and may also be
used to adhere the obstruction to the obstruction removal device as
will be described. In a preferred embodiment, a negative charge is
provided when advancing the obstruction removal device into the
obstruction and a positive charge, or RF energy, is supplied to
adhere the device to the obstruction.
[0011] The devices of the present invention may be manufactured in
any suitable manner. In another aspect of the present invention,
the obstruction removal device has a core element surrounded by a
sheath. A strand, preferably about four strands, are positioned
between the core element and the tube. The strand and the tube
prevent any part of the obstruction removal device from breaking
free should the core element fail. The strand and tube will hold
the obstruction removal device together even if the core element
breaks. The sheath is preferably flexible so that the sheath can
undergo much larger deflections than the core element.
[0012] The obstruction removal devices of the present invention may
also be advanced through a guide catheter having a flow restricting
element which is preferably a balloon but may be any other suitable
structure. The flow restricting element is expanded to reduce blood
flow through the obstructed vessel to minimize the likelihood that
the obstruction will migrate downstream.
[0013] In another aspect of the invention, a system is provided
which has an expandable capture element and an obstruction engaging
device which together work to remove an obstruction from a blood
vessel. The capture element is advanced through the patient in a
collapsed position and is expanded when at the desired location.
The obstruction engaging device preferably has one or more
filaments which provide a relatively flexible interaction between
the engaging device and the capture element. This provides
advantages over the use of a balloon catheter as described in
greater detail below. The obstruction engaging device preferably
has 1-4 filaments and more preferably 1-2 filaments. Of course, the
obstruction engaging device may have more filaments without
departing from various aspects of the invention and, in fact, the
device may form a filter which further helps to prevent portions of
the obstruction from being carried downstream.
[0014] The capture element is preferably naturally biased toward
the expanded position although the capture element may also be
manually actuated as described below. The capture element has a
support structure with a flexible cover attached thereto. The
support structure preferably has a closed loop which opens the
distal end of the cover. The loop is preferably integrally formed
and has a number of integrally formed hinges which deflect when the
loop is expanded and collapsed. The hinges are preferably V-shaped
although other shapes may be used. A plurality of struts extend
proximally from the loop.
[0015] The capture element may also be expanded by the user so that
the user may select the appropriate time for expansion of the
capture element. In this manner, the user may advance the capture
element to a suitable location for expansion. The user may also
collapse the capture element before withdrawing the capture element
into a catheter. The capture element has an actuator for opening
and closing the capture element. The actuator may have a control
arm and a stable arm although any suitable actuator may be used.
The control arm is manipulated to expand and contract a loop at the
distal end of the capture element. Alternatively, the actuator may
be a tube which cinches the loop closed. In a specific embodiment,
the capture element may also evert when moving to the expanded
position.
[0016] The device of the present invention may be used in various
different locations and for various different purposes. In one
embodiment, the device may be used in connection with a guide
catheter. When used with the guide catheter, the device may be
expanded to slow or even stop blood flow when performing other
procedures downstream of the guide catheter such as removing a clot
or placing a stent.
[0017] Alternatively, the device may be passed through a
conventional guide catheter so that the device may be introduced
further into the vasculature. In this system, the capture element
passes through the guide catheter. The obstruction engaging device
is then used to engage the obstruction and move the obstruction
into the capture element.
[0018] These and other advantages of the invention will become
apparent from the following description, drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows a system for removing an obstruction.
[0020] FIG. 2 shows the obstruction removal device in a collapsed
condition.
[0021] FIG. 3 shows the obstruction removal device with a distal
portion of the obstruction removal device expanded.
[0022] FIG. 4 shows the obstruction removal device with a proximal
portion expanded to engage an obstruction.
[0023] FIG. 5 shows another obstruction removal device.
[0024] FIG. 6 shows yet another obstruction removal device.
[0025] FIG. 7 shows still another obstruction removal device.
[0026] FIG. 8 is an end view of the obstruction removal device of
FIG. 7.
[0027] FIG. 9 is an exploded view showing a method of constructing
an obstruction removal device.
[0028] FIG. 10 shows another system for removing an obstruction
from a blood vessel.
[0029] FIG. 11 shows a capture element in an expanded position with
an obstruction engaging element engaging an obstruction
[0030] FIG. 12 shows the obstruction moved into the capture element
with the obstruction engaging element.
[0031] FIG. 13 shows the capture element collapsed and contained
within a catheter.
[0032] FIG. 14 shows an alternative structure for the capture
element.
[0033] FIG. 15 shows another capture element.
[0034] FIG. 16 shows a distal end of the capture element of FIG.
15.
[0035] FIG. 17 shows the support structure for the capture element
of FIGS. 15 and 16.
[0036] FIG. 18 shows the capture element collapsed around the
obstruction prior to withdrawal.
[0037] FIG. 19 shows the capture element contained within the
catheter in an inverted position when collapsed.
[0038] FIG. 20 shows another support structure for the capture
element with the support structure in an expanded position.
[0039] FIG. 21 shows the support structure of FIG. 20 in a
collapsed position.
[0040] FIG. 22 shows still another support structure for the
capture element.
[0041] FIG. 23 shows another capture element having a support
structure which bows outward to preferentially close the distal
end.
[0042] FIG. 24 shows the capture element of FIG. 23 with an
obstruction contained within the capture element.
[0043] FIG. 25 shows another capture element.
[0044] FIG. 26 shows yet another capture element in an expanded
position.
[0045] FIG. 27 shows the capture element of FIG. 26 in a collapsed
position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] Referring now to FIGS. 1-4, a system 2 for removing an
obstruction is shown. A guide catheter 4 is advanced to a location
proximal to an obstruction. When accessing the cerebral
vasculature, for example, the guide catheter 4 is often positioned
in the carotid or vertebral artery. Of course, the guide catheter 4
may not be necessary or may be positioned in any other suitable
location depending upon the location of the obstruction. The guide
catheter 4 preferably has a flow restricting element 6 which
restricts or even stops blood flow through the vessel as described
below. The flow restricting element 6 is preferably a balloon 5
coupled to a source of inflation fluid 7 which is used to inflate
the balloon 5.
[0047] An obstruction removing device 8 is advanced through the
guide catheter 4 to the obstruction. A microcatheter 10 may also be
positioned within the guide catheter 4 to deliver the obstruction
removing device 8 further into the vasculature. The obstruction
removing device may be advanced by itself through the microcatheter
10 or may be contained within a sheath 12 which is advanced through
the microcatheter 10. A source power 14 may also be coupled to the
obstruction removal device 8 for use in the manner explained below.
The power source 14 may simply produce a positive or negative
charge or may be an RF or other suitable power source.
[0048] The obstruction removing device 8 has an engaging element 16
extending from an insertion element 18. The engaging element 16 is
movable from a collapsed position (FIG. 2) to an expanded position
(FIGS. 3 and 4). When the engaging element 16 is contained within
the sheath 12 or microcatheter 10, the engaging element 16 is in a
relatively straight configuration. The engaging element 16 has a
distal portion 20, which forms a relatively closed structure, which
can catch or trap the obstruction, or any part thereof, to prevent
migration of the obstruction or part thereof. The engaging element
16 has a proximal portion 22 which is formed with smaller coils
than the distal portion 20. The proximal portion 22 engages the
obstruction as described below.
[0049] The engaging element 16 preferably has a number of markers
23, 25, 27 which provide an indication as to how much of the
engaging element 16 extends from the sheath 12 or microcatheter 10.
For example, markers 23, 25, 27 may indicate when the engaging
element 16 is {fraction (1/2, 3/4)} or fully exposed. In this
manner, the user may quickly advance the engaging element engaging
element 16 through the sheath 12 or microcatheter 10 without
inadvertently exposing and advancing the engaging element 16 out of
the sheath 12 or microcatheter. The markers 23, 25, 27 can also be
used to provide a controlled diameter of the engaging element 16
since the diameter of the engaging element 16 is known for the
various positions corresponding to the markers 23, 25, 27. The
markers 23, 25, 27 may also be used to size the vessel in which the
engaging element 16 is positioned by observing when the engaging
element 16 engages the vessel walls and determining the size of the
engaging element 16 using the markers 23, 25, 27.
[0050] The insertion element 18 is preferably made of a
superelastic material or stainless steel having a diameter of 0.004
to 0.038 inch and preferably about 0.010 inch. Although the
insertion element 18 is preferably a solid, elongate element, the
insertion element 18 may take any other suitable structure such as
a hollow tube. The engaging element 16 is preferably made of a
superelastic material, such as nitinol, and has a diameter of
0.005-0.018 inch, more preferably 0.005-0.010 inch and most
preferably about 0.008 inch. The engaging element 16 has a rounded,
atraumatic tip 24 to prevent damage to the vessel and facilitate
advancement through the vessel, microcatheter 10 and/or sheath 12.
A radiopaque wire 26, such as platinum ribbon 28 having a width of
0.004 inch and a thickness of 0.002 inch, is preferably wrapped
around the engaging element 16 to improve radiopacity.
[0051] The device 8 is preferably self-expanding but may also be
expanded with an actuator 29. The actuator 29 is preferably a thin
filament which is tensioned to move the device 8 to the expanded
position. An advantage of the invention is that the filament 29
extends through the same lumen as the device 8 thereby minimizing
the overall size of the device. It is understood that throughout
discussion of the devices and methods herein that any of the
devices may be expanded using the actuator 29 rather than being
self-expanding without departing from the scope of various aspects
of the invention.
[0052] The device 8 may also include a cover 9 which extends
between adjacent coils. The cover 9 may be a number of individual
strands 11 which extend between the coils or may be an elastic
membrane which covers the coils. The strands 11 are preferably
elastic to stretch when the device 8 is expanded.
[0053] Use of the obstruction removing device 8 is now described.
The guide catheter 4 is introduced into the patient and delivered
proximal to the target vessel such as to the carotid or vertebral
artery. The microcatheter 10 is then advanced through the guide
catheter 4 further into the vasculature to a position proximal to,
within or distal to the obstruction. The obstruction removal device
8 is then advanced through the microcatheter 10 either by itself or
pre-loaded within the sheath 12. The obstruction removal device 8
is then advanced to the obstruction. Before advancing the
obstruction removal device 8 further, the flow restricting element
6 on the guide catheter 4 is expanded to reduce and even stop flow
through the vessel. Stopping flow in the vessel may help prevent
the obstruction, or any parts thereof, from migrating downstream.
Reducing flow through the vessel may also reduce the likelihood
that the obstruction is disrupted by a combination of flow and the
obstruction removal device 8.
[0054] The obstruction removal device 8 is then placed into the
obstruction and preferably through the obstruction. The engaging
element 16 is then advanced out of the microcatheter 10 or sheath
12 to permit the distal portion 20 of the engaging element 16 to
expand at a location beyond the obstruction. In this manner, the
relatively closed distal portion 20 prevents the obstruction, or
any part thereof, from migrating downstream. The proximal portion
22 is then advanced out of the sheath 12 or microcatheter 10 so
that the smaller coils of the proximal portion 22 engage the
obstruction as shown in FIG. 4.
[0055] Referring to FIG. 5, another obstruction removal device 8A
is shown wherein the same or similar reference numbers refer to the
same or similar structure. The obstruction removal device 8A has a
first section 30 with larger diameter coils than a second section
32. A third section 34 also has larger coils than the second
section 32 with the second section 32 positioned between the first
and third sections 30, 34. The obstruction removal device 8A may
have a number of alternating small and large sections 30, 32, 34
which can enhance the ability of the obstruction removal device 8A
to engage various obstructions. In the preferred embodiment of FIG.
5, the obstruction removal device 8A has four large sections 32, 34
with relatively large coils and three sections 30 having smaller
coils.
[0056] The obstruction removal device 8A may be used in any
suitable manner to engage the obstruction. For example, the
microcatheter 10 or sheath 12 may be advanced through the
obstruction and then retracted to expose the obstruction removal
device 8A. The obstruction removal device 8A is then retracted into
the obstruction to engage the obstruction. The obstruction removal
device 8A may be rotated when moved into the obstruction to take
advantage of the generally helical shape of the obstruction removal
device. The obstruction removal device 8A may also be used to
engage the obstruction by simply retracting the microcatheter 10 or
sheath 12 with the obstruction removal device 8A expanding within
the obstruction. Finally, the engaging element 16A may be exposed
and expanded proximal to the obstruction and then advanced into the
obstruction. When advancing the obstruction removal device 8A into
the obstruction, the user may also twist the obstruction removal
device 8A to take advantage of the generally helical shape. The
alternating large and small sections 30, 32, 34 enhance the ability
of the engaging element 16A to engage varying shapes and sizes of
obstructions.
[0057] Referring to FIG. 6, still another obstruction removal
device 8B is shown wherein the same or similar reference numbers
refer to the same or similar structure. The obstruction removal
device 8B has the insertion element 18 with an engaging element 16B
extending therefrom. The engaging element 16B forms a helical coil
38 with a generally frustoconical shape, however, the engaging
element 16B may take any other shape without departing from the
scope of the invention including any shape disclosed in this
application or any patent incorporated by reference herein.
[0058] A filament 40, preferably a radiopaque filament, is wrapped
around the engaging element 16B. The filament 40 is wrapped
somewhat loosely around the engaging element 16B so that the
filament 40 provides additional surface area to engage the
obstruction. The filament 40 forms a wound section 42, and more
preferably at least five wound sections 42, which are separated by
substantially exposed sections 44 of the engaging element 16B. The
wound and exposed sections 42, 44 may be 1-5 mm long. Stated
another way, the wound and exposed sections 42, 44 are at least 1
mm, more preferably at least 3 mm long, and no more than 8 mm long.
The wound sections 42 may be formed by a single filament 40 which
extends continuously between the wound sections 42 or may be formed
by independent filaments 40 at each wound section 42 which are
attached to the engaging element 16B.
[0059] The wound sections 40 may be movable along the engaging
element 16B to provide flexibility when advancing the obstruction
removal device 8B through small and tortuous vessels. The movable
wound sections 40 may also allow different parts of the obstruction
removal device 8B to grip different parts of the obstruction to
hold the obstruction together or engage different parts of the
obstruction. The obstruction removal device 8B is used in
substantially the same manner as the other obstruction removal
devices described herein. The obstruction removal device 8B has a
handle 41 with a lead screw 43 which engages threads 55. The handle
41 is rotated to advance and retract the engaging element 16B.
[0060] Referring to FIG. 7, still another obstruction removal
device 8C is shown wherein the same or similar reference numbers
refer to the same or similar structure. The obstruction removal
device 8C has an engaging element 16C, which forms a first closed
loop 50, and a second closed loop 52. The first loop 50 is
preferably somewhat larger than the second closed loop 52 with the
first loop 50 having a diameter of about 1.5-8.0 mm and the second
loop 52 having a diameter of about 1.5-6.0 mm. A tip 54 extends
from the first loop 50 for a distance of about 5 mm. A radiopaque
element 56, such as platinum ribbon, is preferably wrapped around
the loops 50, 52 to improve radiopacity and to enhance the ability
of the engaging element 16C to hold the obstruction. The radiopaque
element 56 also may provide advantages when engaging an obstruction
in a manner similar to the obstruction removal devices described
above with reference to FIG. 6.
[0061] An advantage of the obstruction removal device 8C is that
the loops 50, 52 exert substantially equal and opposing forces on
the sheath 12 or microcatheter 10 through which the obstruction
removal device 8C is advanced. In this manner, kinking or binding
of the obstruction removal device 8C during advancement can be
minimized or reduced altogether. Referring to the end view of FIG.
8, the first and second loops 50, 52 preferably lie in first and
second planes 58, 60, respectively, which are preferably
perpendicular to one another.
[0062] Referring to FIG. 9, an exploded view of a construction of
the obstruction removal device 8, 8A, 8B, 8C is shown. A tube 62,
which is preferably a thermoplastic polymer such as polyester or
urethane is positioned over a core element 64. As mentioned above,
the core element 64 is preferably a superelastic or stainless steel
element at either the insertion element 18 or the engaging element
16 (FIGS. 2-7). A reinforcing strand 66 is trapped between the tube
62 and the core element 64 to reinforce the obstruction removal
device. The strand 66 is preferably small and has a diameter or
thickness of less than 0.005 inch, more preferably less than 0.0001
inch, so that the overall size of the obstruction removal device is
not increased significantly with use of the strand 66. The strand
66 may be made of any suitable material including VECTRAN made by
Celanese Acetate LLP or DACRON or KEVLAR which are both
manufactured by Dupont. VECTRAN is a thermoplastic multifilament
yarn spun from a liquid crystal polymer.
[0063] The strand 66 provides a degree of safety in that the strand
66 and tube 62 together prevent any part of the obstruction removal
device from breaking free from the rest of the device. The tube 62
will resist breaking since it is more flexible than the core
element 64 and can undergo larger deflections and displacements
without breaking. In a preferred embodiment, 2-8 strands 66,
preferably about 4 strands 66, are used. The overall size of the
device is also relatively small with the outer diameter of the
resulting structure being no more than 0.020 inch and more
preferably no more than 0.012 inch.
[0064] The power source 14 may be also be used with any of the
obstruction removal devices in the following manner, however, the
methods and devices of the present invention may, of course, be
practiced without the power source 14. As mentioned above, the
power source 14 may simply produce a charge at the engaging element
16 or may be a source of RF energy. In one particular method of the
present invention, the power source 14 produces a negative charge
while advancing the engaging element 16 through the obstruction.
The negative charge may aid in passing the engaging element 16
through the obstruction and may help to dissolve part of the
obstruction. The power supply is then changed to produce a positive
charge to adhere the obstruction to the engaging element 16.
Alternatively, the power source 14 may be an RF energy source,
which delivers RF to the engaging element 16 which also adheres the
obstruction to the engaging element 16 and may help provide a
controlled penetration into the obstruction. The obstruction is
then removed by moving the obstruction into the guide catheter 4,
which is then withdrawn to remove the obstruction. Use of the power
source 14 is particularly useful when the obstruction is a biologic
structure such as a clot.
[0065] Referring to FIGS. 10-14, another system 100 for removing an
obstruction is shown. The system 100 is particularly useful for
removing clots and thrombus from blood vessels but may also be used
to remove other obstructions such as embolic coils and the like.
The system 100 includes an expandable capture element 102 and an
obstruction engaging device 106 which work together to capture the
obstruction. The obstruction engaging device 106 engages the
obstruction and moves the obstruction into the capture element 102
as described below. After the obstruction has been captured, the
capture element 102 may then be used in various ways for ultimate
removal of the obstruction. The capture element 102 may be advanced
through the guide catheter 4 or through another catheter 107 which
is advanced through the guide catheter 4. As will be explained
below, the capture element 102 is preferably advanced over the
obstruction engaging device 106.
[0066] The obstruction engaging device 106 may be any of the
engaging or removal devices described herein or any other suitable
device. Various aspects of the invention preferably include one or
more features of the obstruction removing devices described herein
and all aspects, features, dimensions, and characteristics of the
obstruction removing and engaging devices described herein are
incorporated here. It is understood that the term obstruction
removal device and obstruction engaging device are interchangeable.
The obstruction engaging device 106 may be contained within the
sheath 12 or may be advanced by itself through the guide catheter 4
and/or catheter 107.
[0067] The engaging device 106 may have one or more filaments 108,
preferably 1-4 and more preferably 1-2 filaments, which engage the
obstruction. The filament 108 forms a relatively small, flexible
interaction between the engaging device 106, capture element 102
and obstruction which provides advantages over the prior art method
of using a balloon catheter. The filament 108 may deflect and
displace to accommodate the geometry and orientation of the
obstruction when the obstruction enters the capture element 102.
The interaction between the balloon catheter and the expandable
catheter of the prior art tends to shear off portions of the
obstruction due to the relatively rigid interaction between the
balloon catheter and expanded catheter. The filament 108 also has a
relatively small size which further enhances the flexibility of the
obstruction engaging device 108. The filament 108 may also form one
or more loops 110 which further serve to create a soft, flexible
interaction between the obstruction engaging device 106 and capture
element 102. The filaments 108 may also form a filter which further
prevents the obstruction or portions thereof from travelling
downstream.
[0068] The capture element 102 preferably has a support structure
112 with a flexible cover 114 attached thereto. The support
structure 112 is preferably self-expanding although the support
structure 112 may also be selectively expanded by the user as
explained below. The support structure 112 preferably has a loop
116 having integrally formed hinges 117. The hinges 117 are
preferably formed by V-shaped interconnecting elements 120 although
other shapes, such as U-shaped, may be used. The loop 116 is
preferably formed as an integral structure with the loop 116 being
formed from a tube of material which is cut, etched, treated or
otherwise formed into the loop 116 with hinges 117. The loop is
preferably made of a superelastic material although any suitable
material may be used.
[0069] Struts 122 extend proximally from the loop 116. The struts
122 do not intersect and generally form a cone 124 when expanded.
The struts 122 are coupled to a lumen 121 which receives the
engaging device 106 so that the capture element 102 can be advanced
over the engaging device 106 as described below. Referring also to
FIG. 14, the struts 122 may also be coupled together at a hub 126
at the proximal end. The hub 126 has a lumen 127 which receives the
engaging device 106. A shaft 128 extends from the hub 126 and is
used to manipulate the capture element 102. The struts 122 are
preferably made of a superelastic material or stainless steel and
are attached to the closed loop 116 by soldering, welding, glue or
any other suitable attachment method. The struts 122 may also be
integrally formed with the loop 116. Of course, the supporting
structure 112 may be made of any other suitable material and may be
formed in any other suitable manner. The struts 122 may also be
bowed outward so that the distal end of the device is
preferentially closed before the entire device has been withdrawn
as shown in FIGS. 23 and 24.
[0070] The cover 114 is preferably attached to the support
structure 112 with glue, thread, suture or any other suitable
method. The cover 114 preferably lies over the support structure
112 but may also be contained within the support structure 112. The
cover 114 is relatively long to ensure that the entire obstruction
is captured. The cover 114 is preferably at least three times, more
preferably at least five times, and most preferably at least seven
times larger than the maximum expanded diameter of the support
structure 112 or cover 114. Of course, the capture element 102 may
have any other suitable dimensions depending upon the particular
application. The cover 114 is preferably made of ePTFE but may be
made of any other suitable material. The cover 114 may also be a
mesh-like structure, or any other suitable expandable structure
which can contain the obstruction and parts thereof, without
departing from the scope of the invention.
[0071] Various methods of the present invention are now described.
The methods are described in connection with system 100 of FIGS.
10-14 but may be practiced with other suitable devices and systems.
The present invention is well-suited for use in the cerebral
vasculature and a cerebral application is described, however, the
invention may be practiced in other vascular locations as well.
[0072] The guide catheter 4 is advanced to a suitable location. The
obstruction engaging device 106 is then advanced through the guide
catheter 4. Referring to FIGS. 11 and 12, the obstruction engaging
device 106 is then used to engage the obstruction in any manner
described herein. For example, the sheath 10 (see FIG. 10) may be
advanced through the obstruction and then retracted so that a
proximal portion 111 of the device 106 is contained within the
obstruction. The device 106 is then moved proximally, and is
preferably twisted, so that the loops 110 engage the obstruction.
In the specific embodiment of FIGS. 11-14, the device 106 ensnares
the obstruction with the loops 10 when twisted and moved
proximally.
[0073] The capture element 102 is then advanced over the engaging
device 106. The capture element 102 may be advanced through the
guide catheter 4 or may be advanced through the catheter 107 which
is advanced through the guide catheter 4 further into the cerebral
vasculature. The capture element 102 is then moved out the catheter
107 or guide catheter 4 so that the capture element 102 expands.
The obstruction is then moved into the capture element 102 with the
device 106 as shown in FIG. 13. When the obstruction is contained
within the capture element 102, the capture element 102 is then
withdrawn into the catheter 107 or guide catheter 4 as shown in
FIG. 14. The catheter 107 and/or guide catheter 4 are then
withdrawn from the patient thereby withdrawing the obstruction.
[0074] It may be desirable to reduce or even stop blood flow
through the blood vessel during the procedure to reduce flow forces
on the obstruction when manipulating the obstruction. Reducing flow
in the vessel may also prevent some parts of the obstruction from
breaking off and flowing downstream before entering the capture
element 102. Referring again to FIGS. 10 and 22, blood flow may be
reduced by inflating a balloon 131 on the guide catheter 4 or the
catheter 107. The balloon 131 is inflated using a suitable source
of inflation fluid 133. Alternatively, the capture element 102
itself may also be used to reduce blood flow through the vessel.
The capture element 102 naturally impedes blood flow since it
expands within the blood vessel. The capture element 102 may also
be designed to only partially occlude the vessel so that some blood
flow is provided to the area downstream from the capture element
102. The device 102 may be modified to include a second loop 130
extending between the struts 122 to enhance the ability of the
device 102 to occlude the vessel. The loop 130 preferably has the
features of the loop 116. Although it is preferred to reduce or
even stop flow in the vessel, the invention may also be practiced
without reducing blood flow.
[0075] The devices and methods of the present invention may also be
practiced with a source of vacuum 135 providing suction during
capture of the obstruction. The source of vacuum 135 may be
activated during engagement of the obstruction with the device 106,
movement of the obstruction into the capture element 102, and/or
withdrawal of the capture element 102 into the catheter 107 or
guide catheter 4. The source of vacuum 135 is coupled to the guide
catheter, 4, catheter 107 and lumen 121 for these purposes.
[0076] Referring to FIGS. 10 and 15-17, another capture element 132
for removing an obstruction is shown wherein the same or similar
reference numbers refer to the same or similar structure. The
capture element 132 is selectively expandable by the user which
provides various advantages described below. The cover 114 is
attached to a catheter 134 near or at the distal end 135. The
catheter 134 may be the guide catheter 4 or the catheter 107 in the
system 100 described above. An expandable and collapsible loop 136
is attached to the distal end of the cover 114 to expand and
collapse the distal end of the cover 114. The loop 136 is expanded
and collapsed by manipulating an actuator 138 which includes a
control arm 140 and a stable arm 142. The control arm 140 extends
and slides through an eyelet 144 when expanding and collapsing the
loop 136. The stable arm 142 extends from the loop 136 at or near
the eyelet 144 to stabilize the loop 136 when moving the control
arm 140. The cover 114 is attached to the loop 136 using any
suitable method. For example, the distal end may be inverted to
create a fold 141 which surrounds the loop 136.
[0077] Another advantage of the capture element 132 is that the
capture element 132 may be selectively expanded and contracted by
the user. The capture element 132 may be fully or partially
collapsed to trap the obstruction prior to withdrawal of the
capture element 132 into the catheter 107 or guide catheter 4 as
shown in FIG. 18. In fact, the capture element 132 may be withdrawn
by itself by simply closing the distal end and withdrawing the
capture element 132. In this manner, the capture element 132
protects the obstruction during withdrawal and prevents the
obstruction from escaping. This provides obvious advantages over
the system of Guenther described above.
[0078] Referring to FIGS. 10 and 19, still another capture element
150 is shown in which the same or similar reference numbers refer
to the same or similar structure. The capture element 150 has the
cover 114 and the actuator 138 which includes the stable arm 142,
control arm 140, and loop 136 although other actuating structures
may be used. The capture element 150 is contained within the
catheter 107 or the guide catheter 4 during introduction and is
then everted out of the catheter 107 or catheter 4 when deployed.
The capture element 150 may be used in substantially the same
manner as the other capture elements described herein and in
particular the capture element 132 of FIGS. 15-17. The capture
element 150 may also be used to further collapse the cover 114
since the actuator 138 may be used to close the distal end with the
cover 114 deployed. After the obstruction is contained within the
capture element 150, the capture element 150 is withdrawn into the
catheter 107 or catheter 4. Although it is preferred to withdraw
the capture element 150 into the catheter 4 or catheter 107, the
capture element 150 may be collapsed and then inverted back into
the catheter 4, 107 thereby trapping the obstruction in the
catheter 4, 107 itself.
[0079] Referring to FIGS. 20 and 21, the distal end of yet another
capture element 152 is shown in which the same or similar reference
numbers refer to the same or similar structure. The capture element
152 has a self-expanding support structure 154 with an expandable
loop 156 at the distal end. The loop 156 has a tube 158 which
receives a wire 160 at both ends. The slidable connection between
the tube 158 and wire 160 permits the loop 156 to contract and
expand between the positions of FIGS. 20 and 21. Struts 162 extend
from the loop which engage the catheter to collapse the loop 156.
The cover 114 is attached to the loop 156 by any suitable method.
The capture element 152 is used in any manner described herein. The
capture element 152 is used in any manner described herein and
those methods are incorporated here.
[0080] Referring to FIG. 25, still another device 170 is shown
wherein the same or similar reference numbers refer to the same or
similar structure. The device 170 is similar to the device of FIG.
15 in that the device 170 may be selectively expanded and collapsed
by the user. The device 170 has a collar 172, which may also be a
continuous sheath or tube, which slides over the catheter 107 or
sheath 12. The engaging device 106 passes through the catheter 107
or sheath 12 (FIG. 10) and is used in the manner described herein.
A 174 wire, or other elongate member, is coupled to the collar 172
for advancing and manipulating the collar 172.
[0081] The cover 114 is coupled to a loop 176 which is selectively
expanded by the user as now explained. The loop 176 is manipulated
with the actuator 138 which may be any suitable mechanism. The
actuator 138 has a wire 139 passing through an actuator tube 178
and may also include the stable arm 142. The wire 139 is coupled to
the loop so that movement of the wire 139 opens and closes the loop
176. The actuator tube 178 may be simply advanced to cinch the loop
176 closed. The loop 176 is preferably naturally biased toward the
open position and is held closed by the tube 178.
[0082] The device 170 is used in substantially the same manner as
the other devices described herein and discussion of those methods
are specifically incorporated here. The device 170 may be advanced
by itself through the vasculature with the tube 178 holding the
loop 176 in the closed position. The cover 114 is advanced by
manipulating the tube 178, wire 139 and wire 174. The cover 114 is
advanced over the catheter 107 or sheath 12 and the tube 178 is
retracted to permit the loop 176 to expand. The obstruction is then
introduced into the cover 114 and the cover 114 is then closed by
advancing the tube 178 to cinch the loop 176 closed. The actuator
138 may also be manipulated to open or close the loop 176 together
with the tube 178 or independently of the tube 178.
[0083] Referring to FIGS. 26 and 27, still another device 180 is
shown wherein the same or similar reference numbers refer to the
same or similar structure. The device 180 has the cover 114 and a
loop 182 coupled to the distal end of the cover 114. Stabilizing
struts 184 extend from an end 186 of a tubular body 188 to the loop
182. Actuating arms 190 extend through the body 188 and are also
attached to the loop 182. The arms 190 are manipulated to move the
loop 182 between the collapsed and expanded positions of FIGS. 26
and 27. The engaging device 106 passes through the body 188 and may
be delivered through the catheter 107 or sheath 12. The device 180
is used in substantially the same manner as the device of FIG. 15
and discussion of those methods are incorporated here.
[0084] While the above is a description of the preferred
embodiments of the invention, various alternatives, substitutions
and modifications may be made without departing from the scope
thereof, which is defined by the following claims. Thus, the
preferred embodiments should not be taken as limiting the scope of
the invention. For example, although all of the obstruction removal
devices described herein are self-expanding structures, the
obstruction removal devices may also have actuating mechanisms for
moving the engaging element between the expanded and collapsed
positions. Furthermore, the present invention is directed to a
number of separate inventions and each of these inventions may be
claimed independently of one another. Each feature, aspect and
advantage of the invention may be claimed independent of one
another without departing from the scope of the invention. For
example, use of the power source 14 is independent of the using the
intermittent wound sections 42 but may be used with any of the
devices and methods described herein. As a further example, any
engaging device, even a balloon, may be used with some of the
inventive aspects of the capture element and any capture element
may be used with inventive aspects of the engaging device. Finally,
the devices of the present invention may also be used in connection
with simply controlling blood flow through an area and not
necessarily with removal of an obstruction. Thus, it is understood
that various aspects of the present invention are not limited to
removal of obstructions. Thus, the invention does not include a
single essential feature, aspect or advantage and the invention
should not be limited as such. Finally, the preferred dimensions,
materials and methods of manufacture described for any of the
embodiments is equally applicable for other embodiments.
* * * * *