U.S. patent application number 14/938732 was filed with the patent office on 2016-03-03 for obstruction removal system.
This patent application is currently assigned to MICROVENTION, INC.. The applicant listed for this patent is Heath Bowman. Invention is credited to Heath Bowman.
Application Number | 20160058459 14/938732 |
Document ID | / |
Family ID | 49778878 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160058459 |
Kind Code |
A1 |
Bowman; Heath |
March 3, 2016 |
Obstruction Removal System
Abstract
An obstruction removal device is described, having one or more
engaging members which can engage portions of the clot. The one or
more engaging members have a collapsed, delivery state, and an
expanded, deployed state.
Inventors: |
Bowman; Heath; (Trabuco
Canyon, CA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Bowman; Heath |
Trabuco Canyon |
CA |
US |
|
|
Assignee: |
MICROVENTION, INC.
Tustin
CA
|
Family ID: |
49778878 |
Appl. No.: |
14/938732 |
Filed: |
November 11, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13844148 |
Mar 15, 2013 |
9211132 |
|
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14938732 |
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61665280 |
Jun 27, 2012 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 17/221 20130101;
A61B 2017/2212 20130101; A61B 2017/22034 20130101; A61B 2017/22001
20130101; A61B 17/22032 20130101 |
International
Class: |
A61B 17/22 20060101
A61B017/22; A61B 17/221 20060101 A61B017/221 |
Claims
1. An obstruction removal device comprising: a plurality of linked
engaging members; a proximal structure connected to at least one of
said plurality of independent engaging members; a sheath; wherein
said plurality of independent engaging members include a collapsed
configuration when contained in said sheath and an expanded
configuration when released from said sheath; wherein each of said
engaging members assumes said collapsed and expanded configurations
independently of the other engaging members.
2. The obstruction removal device of claim 1 wherein in said
expanded configuration, at least one of said plurality of linked
engaging members forms a shape selected from the group consisting
of round, oval, elliptical, hourglass, spherical, basket, stent,
countered, rectangular, prismatic and cage.
3. The obstruction removal device of claim 1 wherein at least one
of said plurality of linked engaging members comprises a center of
gravity that is displaced from a geometric center of said engaging
member.
4. The obstruction removal device of claim 1 further comprising a
radiopaque distal structure connected to a distal end of said
plurality of linked engaging members.
5. The obstruction removal device of claim 1 wherein at least one
of said plurality of linked engaging members may rotate
independently of other engaging members.
6. The obstruction removal device of claim 1 wherein each of said
plurality of linked engaging members comprises a cell pattern.
7. The obstruction removal device of claim 1 wherein said cell
patterns of said engaging members are selected based on a function
assigned to each engaging member.
8. A method of removing an obstruction from a body lumen
comprising: navigating a catheter to an obstruction in a body lumen
containing an obstruction removal device therein, said obstruction
removal device including a plurality of linked engaging members in
a collapsed configuration; unsheathing said obstruction removal
device thereby allowing a plurality of linked engaging members to
assume an expanded configuration; retracting said obstruction
removal device through said obstruction; resheathing said engaging
members independently of distally adjacent engaging members;
removing said obstruction removal device and said obstruction.
9. The method of claim 8 wherein navigating a catheter to an
obstruction in a body lumen containing an obstruction removal
device therein, said obstruction removal device including a
plurality of linked engaging members in a collapsed configuration
comprises navigating a catheter to an obstruction in a body lumen
containing an obstruction removal device therein, said obstruction
removal device including a plurality of engaging members, each
engaging member able to rotate independently of the other engaging
members.
10. The method of claim 9 further comprising allowing each of said
plurality of linked engaging members to rotate freely as said
engaging member interacts with said obstruction.
11. The method of claim 8 wherein unsheathing said obstruction
removal device comprises unsheathing said obstruction removal
device distal of said obstruction.
12. The method of claim 8 wherein unsheathing said obstruction
removal device comprises unsheathing said obstruction removal
device such that at least one of said plurality of linked engaging
members is distal of said obstruction and at least one of said
plurality of linked engaging members is not distal of said
obstruction.
13. An obstruction removal device comprising: a plurality of
self-expanding linked engaging members each able to rotate about a
longitudinal axis independently of each other and each including: a
distal end and a proximal end; a collapsed configuration in which
said engaging member is contained within a sheath; an expanded
configuration in which a body of said engaging member between said
proximal and distal ends expands radially while said proximal and
distal ends does not expand such that said engaging member assumes
a bulbous shape.
14. The obstruction removal device of claim 13 wherein in said
bulbous shape is a shape selected from the group consisting of
round, oval, elliptical, hourglass, spherical, basket, stent,
countered, rectangular, prismatic and cage.
15. The obstruction removal device of claim 13 wherein at least one
of said plurality of linked engaging members comprises a center of
gravity that is displaced from a geometric center of said engaging
member.
16. The obstruction removal device of claim 13 further comprising a
radiopaque distal structure connected to a distal end of said
plurality of linked engaging members.
17. The obstruction removal device of claim 13 wherein at least one
of said plurality of linked engaging members expands independently
of other engaging members.
18. The obstruction removal device of claim 13 wherein each of said
plurality of linked engaging members comprises a cell pattern.
19. The obstruction removal device of claim 18 wherein said cell
patterns of said engaging members are selected based on a function
assigned to each engaging member.
20. The obstruction removal device of claim 19 wherein said
functions include dislodging obstructions and catching
obstructions.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/844,148 filed Mar. 15, 2013 entitled Obstruction
Removal System, which claims priority to U.S. Provisional
Application Ser. No. 61/665,280 filed Jun. 27, 2012 entitled
Obstruction Removal System, both of which are hereby incorporated
herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to devices used to capture and
remove obstructions, such as clots or other matter, from the
vascular system, and delivery of these devices to a target area
within the vascular system.
[0003] The buildup of thrombus in vasculature can lead to formation
of blood clots. The formation of clots can result in restricted
blood supply to downstream areas of the vasculature. When these
clots are located in the neurovascular system, these clots can lead
to stroke. Recent technologies to deal with clot removal utilize
devices designed to hold and capture the clot, followed by
withdrawal of the device to physically remove these clots from the
body. Several of these devices may fail to capture the clot in its
entirety, or may promote clot fragmentation which may allow
thrombus to dislodge and accumulate at another site, thus
continuing the risk of stroke. In addition, several of these
devices may promote endothelial denudation due to high friction
between the device and the vessel wall. There is need for an
obstruction removal device which reduces the likelihood of
fragmented thrombus staying in the vasculature while maximizing the
chance of mechanically capturing the clot, and limiting the risk of
endothelial denudation.
SUMMARY OF THE INVENTION
[0004] In one embodiment according to the present invention, an
obstruction removal device is described having a proximal axial
core structure, a distal bumper structure and one or more engaging
members mounted to the distal bumper structure.
[0005] In another embodiment according to the present invention, an
obstruction removal device is described having a proximal
structure, distal structure, and one or more connected engaging
members between the two structures.
[0006] In another embodiment according to the present invention, an
obstruction removal device is described having a proximal
structure, distal structure, and one or more connected engaging
members between the two structures, where at least one of the
engaging members acts as a filter.
[0007] In one example of the previously described embodiments, the
plural engaging members are substantially similar to each
other.
[0008] In another example of the previously described embodiments,
some of the plural engaging members are not substantially similar
to the other engaging members.
[0009] In another example of the previously described embodiments,
some of the plural engaging members actively engage the clot while
one or more of the remaining engaging members do not engage the
clot.
[0010] In one embodiment, the obstruction removal device is
sheathed within a delivery device and delivered through a
catheter.
[0011] In another embodiment, the obstruction removal device is
delivered directly through the catheter.
[0012] In another embodiment, the device is used to retrieve
foreign objects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These and other aspects, features and advantages of which
embodiments of the invention are capable of will be apparent and
elucidated from the following description of embodiments of the
present invention, reference being made to the accompanying
drawings, in which:
[0014] FIG. 1 is an engaging member used in an obstruction removal
device.
[0015] FIG. 2 is another view of the engaging member used in an
obstruction removal device.
[0016] FIG. 3 is an obstruction removal device according to one
embodiment of the present invention;
[0017] FIG. 4 is an obstruction removal device according to another
embodiment of the present invention;
[0018] FIG. 5 is an exploded view of the obstruction removal device
shown in FIG. 4;
[0019] FIG. 6 is a magnified view of the proximal engaging member
of the obstruction removal device of FIGS. 4 and 5.
[0020] FIG. 7 is an obstruction removal device according to another
embodiment of the present invention;
[0021] FIG. 8 is an exploded view of the obstruction removal device
shown in FIG. 7;
[0022] FIG. 9 is one of the distal engaging members used in the
device shown in FIGS. 7 and 8.
[0023] FIGS. 10-12 illustrate a method of deploying the obstruction
removal device described in the previous embodiments.
[0024] FIG. 13 illustrates a hypotube used to create an engaging
member
[0025] FIGS. 14-16 illustrate a process used to help set the final
shape of an engaging member
DESCRIPTION OF EMBODIMENTS
[0026] Specific embodiments of the invention will now be described
with reference to the accompanying drawings. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. The terminology used in the
detailed description of the embodiments illustrated in the
accompanying drawings is not intended to be limiting of the
invention. In the drawings, like numbers refer to like
elements.
[0027] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0028] For the purposes of the terminology described below, the
terms clot, thrombus, embolus, and obstruction can be used
synonymously. Though an obstruction removal device is described,
the device can also be used to capture clot, thrombus, embolus,
foreign bodies, or other matter. Engaging members on the device can
engage clot, thrombus, embolus, foreign bodies, obstructions, or
other matter.
[0029] FIGS. 1 and 2 show an engaging member 100 used with the
obstruction removal device of the present invention. One or more
engaging members are used as part of an obstruction removal device
in order to engage thrombus which can accumulate within a vascular
system. General engaging member shapes can include, but are not
limited to, round, oval, elliptical, hourglass, spherical, basket,
stent, countered, rectangular, prismatic, cage. Each engaging
member 100 has a number of struts 101 which define a number of
cells, or openings 102, and a pair of opposing holes 103 and 104.
For the sake of convention, hole 103 is a distal hole and hole 104
is a proximal hole.
[0030] Each engaging member may be uniquely configured with
different struts, cells, cell sizes, materials, and/or shapes. The
strut design can have a linear, wave, sinusoidal, or zig-zag
pattern, or can have a non-symmetrical design (i.e. where struts on
one side of the engaging member are not mirrored on the other side
of said engaging member). The non-symmetrical strut design may help
facilitate a rotational component on the member as it travels
through a vessel, by shifting the center of gravity from the
geometric center of the engaging member. This ease of rotation
makes it easier for the engaging members, and therefore the
obstruction removal device, to move more easily through the
anatomy, especially after the clot has been engaged and the device
is being pulled back through the vasculature. This ease of rotation
can also limit the amount of damage to the vessel wall due to
excessive contact friction by limiting the damage to a particular
section of the wall. The engaging members may have either identical
or unique designs on each end of the engaging member. This may be
done by varying shape of the struts and/or cells, and/or varying
the cell density of each end, thus--for example--allowing for large
cell sizes on one end and smaller cell sizes on the opposing end.
This variability may allow for different properties to allow for
enhanced ability to engage the clot, or enhanced ability to track
the obstruction removal device and deployed engaging members
through the vessel.
[0031] FIG. 2 shows an engaging member 100 having a plurality of
struts 101 having different thicknesses. More specifically, a
plurality of end struts 101a branch out from the material defining
proximal hole 104, and one or more of these struts 101a split to
form struts 101b. Struts 101b are shown with features 105
protruding therefrom. Features 105 may be any interruption in the
otherwise continuous surface of the strut 101. Non-limiting
examples include barbs, bumps, protrusions, spikes, branches, nubs,
and the like. The struts 101b are then shown as joining an adjacent
struts 101b to form thicker struts 101c, which then split again to
form additional struts 101d, also shown as having features 105.
These struts 101d then join together again to form thicker struts
101e, which are connected to define distal hole 103. As such, it is
seen that, in this particular embodiment, the struts interconnect
to form a web of struts that span from the proximal hole 104 to the
distal hole 103.
[0032] Another strut configuration could utilize a single strut
pattern. An example includes a contiguous, helical strut
configuration running between the proximal and distal ends of the
engaging member, or running between a portion of the length
spanning the proximal and distal ends of the engaging member.
[0033] Each engaging member has a collapsed configuration when
sheathed within a delivery device, and takes on an expanded
configuration as shown in FIGS. 1 and 2 when unsheathed. Each
engaging member can be self-collapsible and self-expandable based
on whether an external force is applied to constrain it (as would
be the case when sheathed in a delivery device), or no constraining
force is present (as would be the case when unsheathed).
[0034] The engaging member may be formed from nitinol, or a similar
material, and may be laser cut to achieve the profile shape. Other
materials and other cutting and/or machining processes would fit
within the scope of the invention.
[0035] The distal and proximal holes, 103 and 104, on respective
distal and proximal end of the engaging member, may facilitate
placement of a common rod on which each engaging member sits, or
they may fit separate connection pieces to connect multiple
components of the obstruction removal device with the respective
engaging members.
[0036] FIG. 3 illustrates an obstruction removal device 200
according to one embodiment of the present invention. The
obstruction removal device comprises a proximal core structure 201
at one end of the device, a distal bumper structure 202 connected
to the proximal core structure 201, and one or more engaging
members 203 mounted to the distal bumper structure 202. In one
example, the device is pushed and/or pulled from the core structure
201 end. A pusher may sit under the core structure, or the core
structure itself may act as a pusher.
[0037] Core structure 201 may be made of a variety of materials,
including, but not limited to, nitinol, stainless steel, cobalt
chromium, or a polymeric material such as PTFE, Pebax, TPE, Engage,
polyethylene, or other similar materials. Core structure
configurations can include, but are not limited to, a coil, a
braid, or a coil/braid combination.
[0038] The bumper structure 202 may be made of a radiopaque
material, including, but not limited to, platinum, tantalum,
palladium, or other similar material. A radiopaque material is
preferred to make imaging of the device easier during the device
insertion procedure, although non-radiopaque materials may also be
used. The engaging members being mounted to the bumper structure,
where the bumper structure is made of a radiopaque material, aids
in imaging the device during the clot removal procedure. The
engaging members may be mounted to the bumper structure in several
ways. For example, the bumper structure may have a threaded outer
profile, where the holes of the engaging members have a
corresponding receiving structure to rotatably mate to the threaded
bumper structure profile. Alternatively, the bumper structure may
have a non-threaded outer configuration, and the engaging members
may be affixed to the bumper structure by a heat treatment
procedure, such as welding. Other mechanical means or other heat
treatment procedures can also be used to affix the engaging members
to bumper structure.
[0039] FIG. 4 illustrates an obstruction removal device 300
according to another embodiment of the present invention. The
obstruction removal device 300 includes a proximal structure 301
connected to one or more engaging members 303. There may be a
distal structure 302 attached to a distal-most engaging member
(labeled as 306 for clarity, though it may be structurally the same
or different as the other engaging members 303). The one or more
engaging members 303 are connected to the proximal structure in
such a way as to allow the one or more engaging members 303 to
rotate independently of the proximal structure 301. The one or more
engaging members 303 may be linked together to allow the engaging
members 303 to rotate independently of each other as well, as
discussed in more detail below. The obstruction removal device 300
is preferably pushed/pulled from one end of the proximal structure
301, thus the terms proximal portion structure and distal structure
are used relative to the pushing/pulling end. Although five
engaging members are illustrated in the figure, fewer or more
engaging members can be used. Like all of the embodiments described
herein, the engaging members 303 are constructed with one or more
struts 101, as described above.
[0040] FIG. 5 illustrates an exploded view of an embodiment of the
obstruction removal device 300 of FIG. 4. The proximal structure
301 may include a core wire 307 which sits under a coil 309, which
may sit under a tube 310. The core wire 307 includes a flared end
308. The core wire 307 may be made of nitinol, or a similar
material, although other materials are within the scope of the
invention. The coil 309 may be made of tantalum, or other
radiopaque materials, although non-radiopaque materials may also be
used. The tube 310 may be made of PET, or other polymeric material,
although non-polymeric materials may be used as well. The proximal
structure also includes another coil 311 which is preferably more
gapped than coil 309, and can be made of a similar material. Coil
311 sits between core wire 307 and the over-coil 309, and helps
center core wire 307 within coil 309. Proximal structure 301 is
connected to a proximal engaging member 302, which can in turn be
connected to another engaging member if more than one engaging
member is used in the obstruction removal device.
[0041] The distal structure 302 includes a monofilament 315 which
sits under a coil 316. Alternatively, multiple monofilaments can be
bonded together to produce a monofilament structure 315. The
monofilament 315 can be made of a stretch-resistant polymer such as
Engage, although other materials may be used. The coil 316 may be
made of tantalum, or other radiopaque materials, although
non-radiopaque materials may also be used. Adhesive, preferably UV
curable adhesive, 317 is used at both ends of the coil structure
316 in order to keep the monofilament 315 integral within the coil
316. In one example, the distal structure can act as a
guidewire.
[0042] A distal structure 302 may be connected to the distal-most
engaging member 306. This distal structure may be radiopaque in
order to aid in imaging of the device during deployment. In the
embodiment of FIG. 5, the coil of the distal structure 302 fits
within the hole 103 of the distal-most engaging member 306, and a
retaining piece 312 fits on the other end to keep the distal
portion 302 integral with engaging member 306. The retaining piece
is welded within the interior of the structure of hole 103. The
engaging member 306 can still rotate. The retaining piece may be of
a tubular construction, and may be made from nitinol, although
similar materials can also be used. In order to aid in imaging, the
retaining piece may be made from nitinol filled with a radiopaque
material. Alternatively, the retaining piece may be coated with a
radiopaque material to aid in imaging of the device during the
procedure. Alternatively, the retaining piece may be made of a
radiopaque material.
[0043] The connection mechanism used to connect the engaging
members together is shown in FIGS. 5 and 6. FIG. 6 illustrates the
connection structure of engaging member 303, which is connected to
the proximal structure 301 of the obstruction removal device.
[0044] The connection mechanism includes a link 313 with two flared
ends 314, and retaining pieces 312. The link 313 may be made of
stainless steel, although similar materials may be used. The flared
ends extend within the opposing holes 103, 104 of the engaging
members being connected, and the retaining piece 312 fits next to
the flared end 314 to secure the link 313 within the hole of the
engaging member. This connecting structure is used to connect the
engaging members together, if more than one engaging member is used
in the obstruction removal device. Retaining piece 312 is welded to
the hole, and the link can rotate while secured within the hole of
the engaging member. The engaging members may independently
rotate.
[0045] Engaging member 303 is also connected to the proximal
structure 301, as shown in FIGS. 5 and 6. The flared end 308 of the
core wire sits past hole 104 of engaging member 303 and a retaining
piece 312 sits over the core wire 307 to secure the proximal
structure 301 to engaging member 303, where retaining piece 312 is
welded within hole 104. A smaller, gapped coil 311 sits within the
distal end of coil 309 and serves to help center the core wire 307
within the coil 309.
[0046] In one example, the connecting piece 313 is placed within
the hole structure, and retaining piece 312 is welded into the hole
over the connecting piece. The flared end 313 can subsequently be
laser welded on the end of the connecting piece. In another
example, the retaining piece 312 is welded into the hole and the
connecting piece is placed within, and the flared end is laser
welded. Although laser welding is specified, other similar heat
treatment techniques can be utilized as well. This procedure can
also be utilized at the end of core wire 307 to produce flared end
308, and to connect proximal-most engaging member 303 to the
proximal portion 301 of the device. In one example, this procedure
can be utilized at the end of the coil 316 when connecting the
distal portion of the device to distal-most engaging member
306.
[0047] Each engaging member has a rotational component; this
ability to rotate can aid in capturing the thrombus and navigating
the vessel. This can also help limit the amount of endothelial
denudation that may occur as the device is being pushed and/or
pulled through the vessel, by helping to limit any excessive forces
that build up due to excessive contact friction between the struts
and the vessel wall. The engaging members may also be configured to
have a more rounded, smoother profile (as illustrated in the
figures) which would eliminate any sharp edges on the engaging
members which may otherwise promote denudation due to high contact
friction. Furthermore, due to the space between the engaging
members, less material physically contacts the vessel than other
designs which may utilize, for example, a longer one-piece clot
engaging unit. Less material contacting the vessel will also serve
to limit endothelial denudation during the clot removal
procedure.
[0048] In one example, the proximal portion 301 of the obstruction
removal device can include means to detach the engaging members
from the obstruction removal device. The detachment means can be
included on the portion of the proximal portion 301 contacting
engaging member 303 (the proximal-most engaging member) and can
include electrolytic, mechanical, thermal, or other means known in
the art to induce severing and/or degradation of a linkage.
[0049] One or more of the engaging members may actively engage the
clot, while other members can sit either distally beyond, or
proximally before, the thrombus--depending on the size of the clot
and the number of engaging members utilized on the device. Due to
the potential variability in the individual shape and/or profile of
each engaging member, as well as the number of engaging members
used in the obstruction removal device compared to the size of the
clot, one or more engaging members may sit distally past the clot
and have a denser cell configuration to act as a filter for
catching thrombus that may dislodge when capturing the clot
utilizing the obstruction removal device. The engaging member(s)
which act as a filter may have a mesh configuration; said mesh
configuration can be throughout the whole engaging member or be
located on one particular side of the engaging member, in order to
maximize the chances of catching loose thrombus without the
thrombus dislodging. In one example, the engaging member(s) which
act as a filter has a denser cell configuration on the more-distal
portion of said member in order to catch thrombus dislodged from
interaction of the more proximal engaging members with the clot.
This arrangement can be useful when the more proximal engaging
members interact with the clot and portions of the clot macerate.
The more distal engaging members with the filter configuration can
catch macerated thrombus that otherwise might accumulate in the
bloodstream. The engaging members which act as a filter may be
formed from nitinol, stainless steel, or similar materials.
Alternatively, they may be formed from laser cut polymers.
Alternatively these engaging members acting as filters may have an
inverted braid configuration, or other basket-type configurations,
or other configurations known within the embolic protection device
art. One or more of the engaging members may also be composed of a
thrombogenic material, or may be coated with a thrombogenic
material in order to aid in the clot retrieval procedure, by
promoting adhesion between the engaging member and the thrombus.
Alternatively, an anti-thrombogenic material can be used, or an
anti-thrombogenic coasting can be used in order to help dissolve a
portion of the clot that is in contact with the engaging members.
This can be useful with, for instance, retrieval operations
involving a large clot.
[0050] FIGS. 7 and 8 illustrate another embodiment of the
obstruction removal device utilizing one or more engaging members
which act as a filter in order to catch thrombus that may become
dislodged during the clot removal procedure. FIG. 7 illustrates the
obstruction removal device, with a proximal portion 401 and distal
portion 402. The proximal portion includes engaging members 303.
The distal portion includes engaging members 407 and 408. The
distal engaging members 407 and 408 have a denser cell
configuration to act as a filter to trap dislodged thrombus which
may shear off during the clot removal procedure, the clot removal
procedure being generally described above. The denser cell
configuration is due to an inner and outer structure used to form
the engaging member, as illustrated in FIG. 8. As illustrated in
FIG. 8, the two distal engaging members 407 and 408 are each
composed of an inner structure 409 and outer structure 410, where
the inner structure may nest within the outer structure. The inner
structure 409 and outer structure 410 which comprise the distal
engaging members 407 and 408 may be made from laser cut nitinol, or
a similar material. The proximal portion 401 and distal portion 402
are configured the same as the embodiment presented in FIGS. 4-5,
as are the linkages between each of the engaging members, although
this filtering engaging member structure can be applied to any of
the engaging members presented in any of the presented obstruction
removal device embodiments.
[0051] The cell pattern may be slightly offset on the inner and
outer structure in order to create a denser cell profile when the
inner structure is nested within the outer structure. As shown in
FIG. 9, the distal part 510 of the engaging member 408 has a denser
cell profile than the proximal part 511 in order to catch
dislocated thrombus which may escape during the clot removal
procedure. This arrangement can be useful when the more proximal
engaging members interact with the clot and portions of the clot
macerate. The more distal engaging members with the filter
configuration can catch macerated thrombus that otherwise might
accumulate in the bloodstream. Although FIGS. 7 and 8 illustrate
two engaging members having the inner and outer structure to act as
a filter, more or fewer engaging members can have this filter
structure.
[0052] In one embodiment for delivery of the device described in
the previous embodiments, an obstruction removal device is sheathed
within a delivery device, and the delivery device is delivered
through a catheter. In one example, the delivery device can be a
microcatheter. The delivery device is delivered to the site of the
obstruction and then pulled back. Pulling back the delivery device
unsheathes the obstruction removal device, such that the engaging
members expand upon retraction of the delivery device.
Alternatively, the obstruction removal device is pushed out of the
delivery device, which subsequently allows the engaging members to
expand. Depending on the number of engaging members on the
obstruction removal device, the size of the clot, and the location
of delivery relative to the obstruction, some members may sit
distally past, and/or proximally before, the obstruction. The
obstruction removal device may be maneuverable via the core wire.
Once the obstruction removal device engages the obstruction, the
delivery device can be withdrawn to a point just past the distal
end of the catheter, and then the catheter can be withdrawn.
Alternatively, the obstruction removal device can be withdrawn from
the vasculature by withdrawing the delivery device into the
catheter, and subsequently withdrawing the catheter, or withdrawing
the delivery device and/or obstruction removal device through the
catheter. Alternatively, the catheter can be withdrawn wholly to
remove the delivery device and obstruction removal device. In
another example, the delivery device can be a hypotube.
[0053] In an alternative embodiment, the device may be delivered
directly through the catheter, without being sheathed in a delivery
device.
[0054] FIGS. 10-12 illustrate an example of a particular method for
deploying the obstruction removal device. In this example, the
delivery device 602 is delivered through the vasculature 600 to the
site of the clot 601. The obstruction removal device 603 is pushed
through the delivery device to the site of the clot. Although this
particular example illustrates the obstruction removal device
deployed in the middle of the clot, the device may be deployed
within the clot, or in a location proximal or distal relative to
the clot location. Some engaging members may sit distally past
and/or proximally before the clot, depending on the size of the
clot and the number of engaging members used on the obstruction
removal device. Delivery device 602 is then retracted which allows
the engaging members of the obstruction removal device to expand
and interact with portions of the clot. The obstruction removal
device 603 can be manipulated by the operator from the proximal
portion 604 of the device. Once the obstruction removal device has
secured the clot, the device can be withdrawn as described above.
Aspiration may also be used to aid in the clot/obstruction removal
procedure. FIGS. 10-12 illustrate a particular example for
illustrative purposes. Other delivery methods are contemplated
within the scope of the invention, such as pushing the obstruction
removal device from the delivery device.
[0055] The engaging members may all be the same size, may all be
different sizes, or may have some engaging members sized
differently from others. In one example, the diameter range for
spherically shaped engaging members may be between 1-12
millimeters. In another example a diameter range of 3-6 millimeters
is used.
[0056] The engaging members are formed from a hypotube which is
laser-cut into a particular pattern based on the shape of the
struts 101 and cells 102. This hypotube 700 is shown in FIG. 13.
The hypotube is heat treated, in one example the hypotube can be
heat set at 530-550 degrees Celsius for 5 minutes. The hypotube is
subsequently quenched in water to cool. An expansion plunger 702 is
then inserted and used to expand a portion of the hypotube (see
FIG. 14). The expanded hypotube is then heat-set to this expanded
shape. In one example it is heat set at 530-550 degrees Celsius for
3 minutes. The expanded hypotube is subsequently quenched in water.
Based on the size of the engaging member, the expansion plunger and
subsequent heat treatment step can be used on multiple portions of
the engaging member, where each section is heat set after
expansion. An expansion pin 704 is subsequently inserted within the
hypotube to help expand the walls of the hypotube (see FIG. 15).
The expanded hypotube 700 is placed in a fixture. The fixture
includes two plates 706, 708. Threaded rods connect the plates, and
the plates have an external mounted nut. The nut can be tightened
to compress the plates together in order to further expand the
hypotube. Once the appropriate shape is set, the expanded hypotube
can be heat treated (in one example, heat treated at 530-550
degrees Celsius for 5 minutes) and quenched to set the shape of the
engaging member.
[0057] The engaging members are subsequently pickled, etched, and
electropolished to set the final shape of the said members. The
obstruction removal device is then assembled together with the one
or more engaging members. Though the engaging members are heat-set
and treated into an expanded shape, they still retain a high degree
of shape memory due to factors such as material properties and
strut thickness. Thus, the engaging members will adopt an expanded
shape when not restrained (i.e. not sheathed in a delivery device)
and will adopt a contracted shape similar to the initial hypotube
shape when restrained (i.e. sheathed in a delivery device).
[0058] In an alternative embodiment, the device mentioned in the
previous embodiments can be used to retrieve foreign objects, in
addition to clots or other obstructions. Circumstances may arise
where foreign objects, such as embolic coils normally used to fill
an aneurysm, may break off or otherwise become detached within the
vasculature. The device can be used to retrieve the foreign body
utilizing a procedure similar to the procedure used during
obstruction removal.
[0059] Although the invention has been described in terms of
particular embodiments and applications, one of ordinary skill in
the art, in light of this teaching, can generate additional
embodiments and modifications without departing from the spirit of
or exceeding the scope of the claimed invention. Accordingly, it is
to be understood that the drawings and descriptions herein are
proffered by way of example to facilitate comprehension of the
invention and should not be construed to limit the scope
thereof.
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