U.S. patent application number 15/294708 was filed with the patent office on 2017-05-04 for embolus removal device with blood flow restriction and related methods.
This patent application is currently assigned to NeuroVasc Technologies, Inc.. The applicant listed for this patent is NeuroVasc Technologies, Inc.. Invention is credited to Jianlu Ma.
Application Number | 20170119408 15/294708 |
Document ID | / |
Family ID | 58630579 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170119408 |
Kind Code |
A1 |
Ma; Jianlu |
May 4, 2017 |
Embolus Removal Device with Blood Flow Restriction and Related
Methods
Abstract
A clot removal device has an expandable treatment member having
a distal tip and a proximal end, a delivery wire having a distal
end coupled to the proximal end of the expandable treatment member,
and a flow restrictor carried along the delivery wire at a location
that is separate and proximal from the expandable treatment member.
The flow restrictor has a body with a distal section and a proximal
section, the distal section being covered and the proximal section
being uncovered. The expandable treatment member is moveable
relative to the flow restrictor, and can be retracted into the
distal section.
Inventors: |
Ma; Jianlu; (Irvine,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NeuroVasc Technologies, Inc. |
Laguna Hills |
CA |
US |
|
|
Assignee: |
NeuroVasc Technologies,
Inc.
Laguna Hills
CA
|
Family ID: |
58630579 |
Appl. No.: |
15/294708 |
Filed: |
October 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62251069 |
Nov 4, 2015 |
|
|
|
62249249 |
Oct 31, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/0021 20130101;
A61F 2002/016 20130101; A61B 2090/3966 20160201; A61F 2/013
20130101; A61F 2230/0067 20130101; A61M 2025/0042 20130101; A61B
17/12131 20130101; A61B 2017/1205 20130101; A61B 17/12109 20130101;
A61B 2017/2212 20130101; A61B 90/39 20160201; A61B 2017/00867
20130101; A61B 2017/22038 20130101; A61B 2017/2215 20130101; A61B
2017/00893 20130101; A61B 2017/22079 20130101; A61B 2017/2217
20130101; A61B 17/221 20130101 |
International
Class: |
A61B 17/221 20060101
A61B017/221 |
Claims
1. A method for removing a clot or embolus from a blood vessel,
comprising: providing a clot removal device, comprising: an
expandable treatment member having a distal tip and a proximal end;
a delivery wire having a distal end coupled to the proximal end of
the expandable treatment member; a flow restrictor carried along
the delivery wire at a location that is separate and proximal from
the expandable treatment member, the flow restrictor having a body
with a distal section and a proximal section, the distal section
being covered and the proximal section being uncovered; delivering
an access catheter to a location proximal to a location of a clot
or embolus in a blood vessel; delivering the clot removal device
through a lumen in the access catheter to the location of the clot
or embolus in the blood vessel; expanding the expandable treatment
member at a location that is at or distal to the location of the
clot or embolus; catching or engaging the clot or embolus in or
with the expandable treatment member; positioning the access
catheter with respect to the flow restrictor such that the
uncovered proximal section is completely covered by the distal end
of the access catheter and the covered distal section forms a seal
with the distal end of the access catheter; and applying aspiration
through the access catheter and through the uncovered proximal
section to remove the clot or embolus from the blood vessel.
2. The method of claim 1, further including the step of withdrawing
the expandable treatment member into the distal section of the flow
restrictor.
3. The method of claim 2, further including the step of withdrawing
the expandable treatment member and the flow restrictor from the
blood vessel.
4. The method of claim 1, wherein the uncovered proximal section
has a smaller diameter than the covered distal section.
5. The method of claim 4, wherein the uncovered proximal section is
tapered and the covered distal section is cylindrical.
6. The method of claim 4, wherein the covered distal section is
covered by a biocompatible polymer covering.
7. The method of claim 1, wherein the expandable treatment member
is configured to define a catch basket.
8. A method for removing a clot or embolus from a blood vessel,
comprising: providing a clot removal device, comprising: an
expandable treatment member having a distal tip and a proximal end;
a delivery wire having a distal end coupled to the proximal end of
the expandable treatment member; a flow restrictor carried along
the delivery wire at a location that is separate and proximal from
the expandable treatment member, the flow restrictor having a body
that defines a receiving section; delivering the clot removal
device to a location of a clot or embolus in a blood vessel;
expanding the expandable treatment member at a location that is at
or distal to the location of the clot or embolus; catching or
engaging the clot or embolus in or with the expandable treatment
member; withdrawing the expandable treatment member into the
receiving section of the flow restrictor; and withdrawing the
expandable treatment member and the flow restrictor from the blood
vessel.
9. The method of claim 8, wherein the step of withdrawing the
expandable treatment member into the receiving section of the flow
restrictor is performed with the flow restrictor held stationary
with respect to the expandable treatment member.
10. The method of claim 8, further including applying aspiration
through the flow restrictor to remove the clot or embolus from the
blood vessel.
11. A clot removal device, comprising: an expandable treatment
member having a distal tip and a proximal end; a delivery wire
having a distal end coupled to the proximal end of the expandable
treatment member; and a flow restrictor carried along the delivery
wire at a location that is separate and proximal from the
expandable treatment member, the flow restrictor having a body with
a distal section and a proximal section, the distal section being
covered and the proximal section being uncovered.
12. The device of claim 11, wherein the uncovered proximal section
has a smaller diameter than the covered distal section.
13. The device of claim 12, wherein the uncovered proximal section
is tapered and the covered distal section is cylindrical.
14. The device of claim 12, wherein the covered distal section is
covered by a biocompatible polymer covering.
15. The device of claim 11, wherein the expandable treatment member
is configured to define a catch basket.
16. The device of claim 11, wherein the expandable treatment member
is moveable relative to the flow restrictor.
17. The device of claim 11, wherein the expandable treatment member
is retractable into the distal section of the flow restrictor.
Description
RELATED CASES
[0001] This application claims priority from U.S. Provisional
Application Ser. No. 62/249,249, filed on Oct. 31, 2015, and U.S.
Provisional Application Ser. No. 62/251,069, filed on Nov. 4, 2015,
the contents of each of which are incorporated by this reference as
if fully set forth herein in their entirety.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The present invention generally relates to devices and
methods useful for clot retrieval, and removal devices to treat,
among other things, ischemic stroke.
[0004] Description of the Prior Art
[0005] Currently, the FDA-approved treatment options for an acute
ischemic stroke include intravenous (IV) delivery of clot
dissolving medicine and mechanical thrombectomy.
[0006] For treatment use, clot dissolving medicine, such as the
thrombolytic agent (Tissue Plasminogen Activator (t-PA)), is
injected into the vasculature to dissolve blood clots that are
blocking blood flow to the neurovasculature. Intravenous t-PA is
currently limited in use because it must be used within a
three-hour window from the onset of a stroke and can result in an
increased risk of bleeding. This standard of care leaves room for
upgrade, and is only the appropriate approach to treatment for a
limited class of individuals, groups and temporally-limited exigent
cases.
[0007] A second option includes the use of mechanical thrombectomy
devices. Such devices are designed to physically capture an embolus
or clot, and to remove it from the blocked vessel, thereby
restoring blood flow. The major advantage of the mechanical
thrombectomy device is it can expand the treatment window from
three hours to over ten hours.
[0008] Some existing mechanical thrombectomy devices used for
increasing blood flow through an obstructed blood vessel include:
1) a filter trap designed and built to collect and remove emboli;
2) a cork-screw guidewire-like device to retrieve embolus; and 3) a
stent-like device connected to a delivery wire to retrieve embolus.
All of these devices suffer from certain disadvantages.
[0009] First, filter-type thrombectomy devices tend to be
cumbersome and difficult to deliver and deploy, and a
larger-profile guide catheter may be needed to fully remove the
embolus. In addition, it is difficult to coordinate precise and
predictable movement to position the device properly in the vessel.
The device can drift within the vessel, twist, or not be adequately
conforming to the vessel wall and, therefore not effective for
removing embolus.
[0010] Cork-screw guidewire devices can only capture and remove
emboli that are firm, or subject to certain mechanical variables
such as being held together by itself as one piece. Cork-screw
guidewire devices are not effective in removing particulate matter
that may be scattered or broken up.
[0011] Stent-like mechanical thrombectomy devices are not capable
of capturing small emboli that break off from a large embolus (if
any), and can lead to complications such as the blockage of distal
smaller vessels, vessel dissection, perforation, and hemorrhage
arising as a result of over-manipulation in the vessel.
[0012] The disadvantages common to all of the devices described
above include, for example: 1) the device may capture an embolus,
but then lose grasp of it and migrate/deposit it incidentally into
another area of the neurovasculature, creating the potential for a
new stroke in a different part of the neurovasculature; 2) the
device is not capable of capturing small embolus breaking off from
the larger embolus and preventing it from migrating to a more
distal area of the neurovasculature; 3) the relative large device
profile prevents these devices from treating the distal smaller
diameter vessels; and 4) risk of sICH (symptomatic Intra-cerebral
Hemorrhage) after intra-arterial clot removal in acute stroke
patients.
[0013] Other flaws in the current mechanical thrombectomy designs
include poor visibility/radiopacity, lack of variation in the
delivery portion to enhance and improve deliverability, and lack of
coatings or modified surface textures on the treatment portion to
enhance embolus affinity, etc. In conclusion, there is a great need
for improved devices, systems, and methods for restoring blood flow
through a blood vessel. None of the existing medical mechanical
thrombectomy devices address all necessary needs to date.
SUMMARY OF THE DISCLOSURE
[0014] The present invention is directed to a method and devices
for removing clots, emboli and other luminal blockages from a blood
vessel. A clot removal device is provided, having an expandable
treatment member having a distal tip and a proximal end, a delivery
wire having a distal end coupled to the proximal end of the
expandable treatment member, and a flow restrictor carried along
the delivery wire at a location that is separate and proximal from
the expandable treatment member. The flow restrictor has a body
with a distal section and a proximal section, the distal section
being covered and the proximal section being uncovered. An access
catheter is delivered to a location proximal to a location of a
clot or embolus in a blood vessel, and then the clot removal device
is delivered through a lumen in the access catheter to the location
of the clot or embolus in the blood vessel. The expandable
treatment member is expanded at a location that is at or distal to
the location of the clot or embolus, and the clot or embolus is
caught in, or engaged with, the expandable treatment member. The
access catheter is then positioned with respect to the flow
restrictor such that the uncovered proximal section is completely
covered by the distal end of the access catheter and the covered
distal section forms a seal with the distal end of the access
catheter, and then aspiration is applied through the access
catheter and through the uncovered proximal section to remove the
clot or embolus from the blood vessel.
[0015] The clot removal device of the present invention can also be
used in accordance with another method, where the clot removal
device is delivered to a location of a clot or embolus in a blood
vessel, the expandable treatment member is expanded at a location
that is at or distal to the location of the clot or embolus, the
clot or embolus is caught in, or engaged with, the expandable
treatment member, the expandable treatment member is withdrawn into
the distal section of the flow restrictor, and the expandable
treatment member and the flow restrictor are withdrawn from the
blood vessel.
[0016] The devices of the present invention can be made from either
metallic biocompatible material (such as Nitinol, stainless steel,
Co--Cr base alloy, Ta, Ti, etc.) or polymer based biocompatible
material (polymers with shape memory effect, PTFE, HDPE, LDPE,
Dacron, Polyester, etc.). For ischemic stroke treatment, the
expandable treatment member must be flexible enough to negotiate
the torturous vasculature of the brain and without modifying the
vessel profile at the target location. The profile of the
expandable treatment member must be small enough to reach target
treatment site as known to artisans.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a side view of a fully expanded clot removal
device according to a first embodiment of the present
invention.
[0018] FIG. 2 is a side view of the clot removal device of FIG. 1
shown in a compacted orientation inside a microcatheter.
[0019] FIG. 3A is a side view of the clot removal device of FIGS. 1
and 2 shown with the expandable treatment member fully pushed
outside the microcatheter.
[0020] FIG. 3B is a side view of the clot removal device of FIGS. 1
and 2 shown with the control arms and the expandable treatment
member slightly pushed outside the microcatheter.
[0021] FIG. 4 is a side view of a fully expanded clot removal
device according to a second embodiment of the present
invention.
[0022] FIG. 5 is a side view of the clot removal device of FIG. 4
showing the collection of a clot in a vessel.
[0023] FIG. 6A is a side view of the clot removal device of FIG. 4
showing the clot collected inside the expandable treatment
member.
[0024] FIG. 6B is a side view of the clot removal device of FIG. 4
showing the clot collected inside the expandable treatment member,
and the expandable treatment member inside the proximal flow
restrictor.
[0025] FIG. 7 is a side view of a fully expanded clot removal
device according to a third embodiment of the present invention
shown with a clot caught on the surface of, and between the cell
spaces, of the expandable treatment member.
[0026] FIG. 8 is a side view of the clot removal device of FIG. 7
showing the expandable treatment member being pulled into the
proximal flow restrictor.
[0027] FIG. 9 is a side view of the clot removal device of FIG. 7
showing the expandable treatment member inside the proximal flow
restrictor.
[0028] FIG. 10 is a side view of a fully expanded clot removal
device according to a fourth embodiment of the present
invention.
[0029] FIG. 11 is a side view of the removal device of FIG. 10
showing the expandable treatment member being pulled into the
proximal flow restrictor with the clot engaged on its outer
surface.
[0030] FIG. 12 is a side view of the removal device of FIG. 10
showing the expandable treatment member inside the proximal flow
restrictor.
[0031] FIG. 13A is an enlarged side view of an exemplary proximal
flow restrictor design.
[0032] FIG. 13B is an enlarged side view of an exemplary proximal
flow restrictor design with a push wire connected from the proximal
end.
[0033] FIG. 13C is an enlarged side view of an exemplary proximal
flow restrictor design with a through lumen on the delivery element
from the proximal end.
[0034] FIG. 14A is an exemplary application of the proximal flow
restrictor of FIG. 13B combined with an access catheter, such as a
guide catheter, or other procedure support catheters (not in
aspiration position).
[0035] FIG. 14B is an exemplary application of the proximal flow
restrictor of FIG. 13B combined with an access catheter, such as a
guide catheter, or other procedure support catheters, in an
aspiration position.
[0036] FIGS. 15A-15C illustrate another embodiment of the clot
removal device according to the present invention where the
expandable treatment member is omitted.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] The following detailed description is of the best presently
contemplated modes of carrying out the invention. This description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating general principles of embodiments of the
invention. The scope of the invention is best defined by the
appended claims.
[0038] The present invention is directed to a device for removing
emboli and other luminal blockages. The device includes an
expandable treatment member, such as a mesh or a cage, that is
associated with a proximal flow restrictor. During treatment, the
expandable treatment member is positioned within or distal to an
embolus within a blood vessel and then transitioned into an
expanded state. In certain embodiments, the expandable treatment
member's normal state is the expanded configuration, and the
expandable treatment member is compacted and delivered to the
treatment site in the compacted configuration through a delivery
sheath or catheter. The expandable treatment member is deployed,
from the delivery sheath, which causes it to return to its normal
expanded profile by the elastic energy stored in the device.
Expansion of the expandable treatment member engages the expandable
treatment member with the emboli or clot at the blockage. In
addition, the proximal flow restrictor can also expand to a larger
diameter state when it is deployed from the delivery sheath or
catheter. Expansion of the proximal flow restrictor advantageously
limits or restricts forward blood flow and creates a pressure
gradient within the blood vessel between locations distal and
proximal to the flow restrictor. The pressure gradient helps to
prevent the clots from being flushed away from the treatment
member, thereby assisting in removal of the embolus from the blood
vessel. Specifically, the pressure difference can act like a vacuum
to assist in removal of the embolus from the blood vessel. After
expansion, the expandable treatment member and the emboli engaged
with the expandable treatment member are removed from the blood
vessel. During clot removal, the expandable treatment member (with
the blood clot engaged) can also be pulled inside the proximal flow
restrictor first (i.e., the clot retrieval component with clots
engaged are housed inside proximal restrictor), and then pulled
back into guide catheter, and removed from the blood vessel.
Furthermore, aspiration/vacuum suction can be applied through the
lumen of the access catheter lumen and proximal flow restrictor to
prevent clots from breaking off and flowing downstream.
[0039] In addition, the proximal flow restrictor regulates the
forward blood flow and allows the controlled (gradual) restoration
of the blood flow, and reduces the risk of sICH (symptomatic
Intra-cerebral Hemorrhage) after intra-arterial clot removal in
acute stroke patients.
[0040] Devices of the present invention are suitable for removal of
blockages in body lumens, and are particularly well-suited for
removal of thrombi, emboli, or atheroma in the vasculature,
including those in arteries and veins. It is understood that the
dimensions of the device may be modified to suit a particular
application. For example, devices of the invention used for
treatment of deep vein thrombosis may have a larger cross-section
than devices of the invention used for treatment of brain
ischemia.
[0041] Compared with existing mechanical thrombectomy devices, the
unique device design included in this invention has the advantage
of providing a proximal flow restriction feature to block the
forward flow of blood when the device is deployed during use. This
feature can help to eliminate or reduce the risk of flush, or the
break-up of the blood clots during the procedure.
[0042] Another important advantage provided by the present
invention is the central lumen of the proximal flow restrictor can
be used or combined with the lumen of the access catheter to apply
aspiration/suction force to help with the complete removal of the
blood clots in the vasculature.
[0043] Thus, the device described in the present invention
overcomes the shortcomings of the existing technologies and can be
delivered to the target vasculature smoothly, can be retrieved
safely, and can remove the entire embolus with fewer passes. In
use, the mechanical thrombectomy device described in the present
invention can be compacted to a low profile and loaded onto a
delivery system and delivered to the target location in the vessel
by a medical procedure such as through use of a delivery catheter.
The mechanical thrombectomy device can be released from the
delivery system when it reaches the target implant site and
expanded to its normal expanded profile by the elastic energy
stored in the device (self-expandable device).
[0044] As for the relative position of the expandable treatment
member in relation to the embolus or blood clot, it can either be
deployed at the site of the embolus, or deployed distal to the
embolus. In dealing with long embolus, the expandable treatment
member can also be used to remove the embolus from the proximal
portion to the distal portion with multiple passes, until the
entire embolus is removed.
[0045] Turning now to the drawings, FIGS. 1-2 illustrate a device
100 for removing emboli and other luminal blockages according to
the present invention. The device 100 can be made from one piece or
multiple pieces of Nitinol.TM. super elastic material or
Nitinol.TM. super-elastic alloy tubing. It can also be made from
other biocompatible materials that exhibit super-elastic or shape
memory properties. The device 100 can be made by laser cutting,
mechanical machining, chemical machining, electrochemical
machining, EDM, braiding and related techniques known to those
skilled in the art.
[0046] The device 100 has an expandable treatment member 102
carried along a delivery wire 104 adjacent the distal end of the
delivery wire 104. The delivery wire 104 has a soft distal tip 106
that extends distal from the expandable treatment member 102, and
has a marker coil embedded therein. A plurality of laser cut
control arms 108 couple the proximal portion of the expandable
treatment member 102 with a hub 110 along the delivery wire 104.
Specifically, each control arm 108 has opposite ends connecting the
proximal portion of the expandable treatment member 102 and the hub
110. A proximal flow restrictor 112 is carried on the delivery wire
104 proximal to the hub 110. Marker bands or marker coils can be
incorporated into the proximal flow restrictor 112 and the
expandable treatment member 102 for visibility. At least one end of
the proximal flow restrictor 112 can move freely along the delivery
wire 104.
[0047] The expandable treatment member 102 can be configured to act
as a catch basket for the clot or embolus, and in this embodiment
is shaped as a cone in its fully expanded configuration, with an
apex 120 at the distal-most portion of the expandable treatment
member 102 secured to the delivery wire 104 adjacent the distal tip
106, and with the expandable treatment member 102 increasing
radially in diameter until reaching its proximal-most ring 122. The
expandable treatment member 102 can be made of a Nitinol.TM.
braided mesh and can be shape-set to the cone shape by a thermal
mechanical process. Most significantly, the expandable treatment
member 102 is not cylindrical in configuration which allows it to
better conform to the vessel contour and to move more freely inside
the vessel. The size of the opening for the ring 122 can range from
0.5 mm to 12 mm. The length of the distal cone portion from the
apex 120 to the ring 122 can range from 2 mm to 40 mm.
[0048] The meshed frame of the expandable treatment member 102 can
be provided with a plurality of openings. Frame members or struts
form the body of the meshed frame and define the plurality of
openings. In certain embodiments, the frame members are a plurality
of intersecting wires or other threads. The frame members may form
a mesh or cage-like structure that defines the plurality of
openings. In certain embodiments, the expandable treatment member
102 can include a plurality of protrusions 150 on the frame. See
FIG. 1 The plurality of protrusions 150 further engages the embolus
for removal.
[0049] As an alternative to, or in addition to, the plurality of
protrusions 150, the expandable treatment member 102 may include
one or more surface modifications or treatments. For example, as
explained in greater detail below, the surface of the expandable
treatment member 102 may be roughened to improve clot adhesion. The
main geometrical axis of the expandable treatment member 102 can be
offset or different from the longitudinal center axis of the native
blood vessel. When the expandable treatment member 102 is in use,
both the delivery catheter (e.g., microcatheter 124) and/or the
movement axis of the expandable treatment member 102 can be
different from the longitudinal central axis of the vessel, and can
contact the side wall of the blood vessel.
[0050] The delivery wire 104 can be made of super-elastic Nitinol
wire, stainless steel wire, braided stainless steel wire, Co--Cr
alloy and other biocompatible materials. The diameter of the
delivery wire 104 can range from 0.008'' to 0.030'', and the
delivery wire 104 can have variable diameters/stiffness along its
length.
[0051] This distal tip 106 can be made of Ta, Pt, W, Pt--W, or
Pt--Ir alloys for radiopacity, and from radiopaque coils or
markers.
[0052] The control arms 108 can be laser-cut from a super-elastic
Nitinol material. They are preferably taut when the expandable
treatment member 102 is in its full expanded configuration. The
control arms 108 function to control the opening diameter of the
ring 122, so that the largest diameter of the ring 122 can be
achieved when the control arms 108 are completely pushed out of the
sheath of a microcatheter 124 (see FIG. 2). The diameter of the
ring 122 can be adjusted by the length of the control arms 108
being pushed out of the microcatheter 124. Even though the present
embodiments are being described as having three control arms 108,
it is possible to provide one, or more than two, control arms
108.
[0053] The hub 110 can be made from radiopaque materials, and can
move freely along, and with respect to, the delivery wire 104. The
hub 110 can also be secured to a fixed location along the delivery
wire 104
[0054] The proximal flow restrictor 112 can be a bulbous structure
and can be made of a Nitinol.TM. mesh, and it is fixedly connected
to the delivery wire 104 at its proximal end, while the distal end
of the proximal flow restrictor 112 can move freely along, and with
respect to, the delivery wire 104. In another embodiment, the
proximal flow restrictor 112 can be fixedly connected to the
delivery wire 104 at its distal end, while the proximal end of the
proximal flow restrictor 112 can move freely along, and with
respect to, the delivery wire 104. The proximal flow restrictor 112
can have a first smaller compacted profile for delivery through the
microcatheter 124 possible. The proximal flow restrictor 112 can
have a second larger expanded diameter/profile when released from
the microcatheter 124 or other delivery system to block, limit, or
restrict the blood flow. The bulbous structure can be a braided or
laser cut structure, and made from a film, membrane, braided or
netted material. In certain embodiments, the proximal flow
restrictor 112 is a polymeric film or membrane. In other
embodiments, the proximal flow restrictor 112 is a braided or woven
net formed from a metal, polymer, or combination thereof. The type
and material of the proximal flow restrictor 212 may be chosen
based on the desired coverage (i.e. amount of flow to be
restricted). The surface of the proximal flow restrictor can be
either entirely or partially covered by some polymer materials to
restrict the blood flow. It can be fabricated from the one or two
element(s) of the device 100, or fabricated from other pieces of
material, then attached to the delivery wire 104 by mechanical
means, or via a thermal (laser or soldering) process, or
adhesive/glue, or heat shrink technology. The bulbous structure can
also be fabricated from the same piece of Nitinol.TM. tubing as
that of the device 100 by laser cutting or chemical processes and
then shape-set to a larger diameter than the raw Nitinol.TM.
tubing.
[0055] The proximal flow restrictor 112 can have a diameter in its
fully expanded configuration that is about the same as the diameter
of the opening ring 122 of the expandable treatment member 102 when
the expandable treatment member 102 is in its fully expanded
configuration. The diameter of the proximal flow restrictor 112 can
range from 0.5 mm to 12 mm, and its length can range from 2 mm to
60 mm.
[0056] Radiopaque markers can be attached on any portion of the
device 100 for positioning. One way to provide full visibility for
the device 100 is to run a radiopaque material through the entire
or partial lumen of the delivery wire 104. Markers can also be
placed on the expandable treatment member 102 to aid in
positioning. In addition, radiopaque markers (marker coils, marker
bands, radiopaque wire(s), radiopaque coatings, etc.) can be
integrated into the proximal flow restrictor 112.
[0057] The device 100 can have a surface treatment on selected
portions to improve performance for the selected portions of the
device 100. Both the proximal flow restrictor 112 and the
expandable treatment member 102 can either be coated or covered,
entirely or partially, by typical biocompatible materials for
lubricity. The surface of the expandable treatment member 102 can
have either a positive or negative charge for improved clot
adhesion. The surface of the expandable treatment member 102 can
also be either mechanically or chemically treated to have a "rough"
surface for improved clot adhesion. The "rough" surface can be
achieved by (i) a porous surface coating or layer (ii) a micro
blasted surface or micropinning, or (iii) an irregular strut
geometry or arrangement.
[0058] The expandable treatment member 102 can be fully or
partially coated with chemical(s), drug(s) or other bioagents to
prevent clotting and/or for the better adhesion between the device
and embolus. In addition, the surfaces of the expandable treatment
member 102 and the proximal flow restrictor 112 can be treated to
form different surface layers (e.g., oxidation layer, Nitro or
carbonized or N--C-combined surface layer, etc.) for better
adhesion between the expandable treatment member 102 and the
embolus.
[0059] FIG. 2 shows the device 100 compressed and fitted inside a
microcatheter 124. In use, a guide wire can be inserted through the
vasculature to the target treatment site, and then the
microcatheter 124 is delivered over the guide wire to a target
location in a vessel with the device 100 housed therein using
conventional delivery techniques that are known to those skilled in
the art. Alternatively, the microcatheter 124 can be inserted over
the guide wire first, then the compacted device 100 can be inserted
through the inner lumen of the microcatheter 124. The distal end of
the microcatheter 124 can be positioned proximal to, or inside, or
distal to, the clot or embolus at the target location, and there is
no need for the microcatheter 124 to traverse the clot or embolus,
thereby minimizing the possibility of pushing the clot or embolus
downstream in the vessel.
[0060] The microcatheter 124 can then be pulled back (proximally)
to expose first the expandable treatment member 102 (see FIG. 3A),
then the control arms 108, and then later on the proximal flow
restrictor 112. Before the control arms 108 are fully exposed, the
expandable treatment member 102 will not reach its full diameter,
which makes it possible for the expandable treatment member 102 to
not disturb clots before the device 100 reaches its desired
position. Instead of pulling back the microcatheter 124, it is also
possible to deploy the expandable treatment member 102 by inserting
the device 100 into the microcatheter 124 until the distal tip 106
reaches the distal end of the microcatheter 124, and then holding
the proximal end of the microcatheter 124 in a stationary position,
pushing the device 100 distally out of the microcatheter 124. Under
this alternative, there is no need to withdraw the microcatheter
124, which allows the positioning to be more accurate. The
expandable treatment member 102 will not fully deploy (i.e., reach
its largest diameter) until the control arms 108 have been
completely pushed out of the microcatheter 124. This allows for a
gap, volume, or space (see FIG. 3B) between the expandable
treatment member 102 and the actual clot in the vessel, so that the
clot will not be pushed downstream and dislodged by the expandable
treatment member 102 when the expandable treatment member 102 is
pushed out of the microcatheter 124 and located distal to the clot.
Once the control arms 108 have been completely pushed out of the
microcatheter 124, then the expandable treatment member 102 will
reach its full diameter to catch the clot from the distal side of
the clot. At this point, the microcatheter 124 and the elongated
delivery wire 102 will be pulled back or withdrawn at the same time
to remove the clot.
[0061] During this procedure, the proximal flow restrictor 112
eliminates or reduces the forward blood flow to minimize the risk
of poor clot retention and clot dislodgement. The expandable
treatment member 102 can collect all the clots/emboli to prevent
them from flowing downstream. The proximal flow restrictor 112 also
regulates the flow of blood during and immediately after the
procedure to eliminate the effect of sICH for a better clinical
outcome.
[0062] In other embodiments, the proximal flow restrictor can
surround (i) an outer surface or diameter of a proximal portion of
the expandable treatment member, or (ii) both the inner and outer
surfaces or diameters of the proximal portion of the expandable
treatment member. In these embodiments, the proximal flow
restrictor can cover a length extending between (i) a proximal end
of the expandable treatment member to about half of the length of
the expandable treatment member, or (ii) between a proximal end of
the expandable treatment member to about one-quarter of the length
of the expandable treatment member.
[0063] For example, FIGS. 4-6 illustrate another embodiment of a
device 200 for removing emboli and other luminal blockages. The
device 200 also has an expandable treatment member 202, a soft
distal tip 206 (with marked coil), a delivery wire 204, control
arms 208, a hub 210 and a proximal flow restrictor 212 that
correspond to the expandable treatment member 102, soft distal tip
106 (with marked coil), delivery wire 104, control arms 108, hub
110 and proximal flow restrictor 112, respectively, for the first
embodiment, except for a few differences.
[0064] First, the expandable treatment member 202 has a slightly
different configuration. Instead of the conical configuration of
the expandable treatment member 102, the expandable treatment
member 202 has a frusto-conical body 228 where its distal-most end
does not terminate in an apex, but has a small distal opening.
[0065] Second, the proximal flow restrictor 212 has a different
configuration, having a body that includes a cylindrical distal
section 230 and a generally conical (or frusto-conical) proximal
section 232 that has a tapering configuration. The two sections 230
and 232 combine to define a receiving section.
[0066] The body 228 and the sections 230 and 232 can all be laser
cut from the same material (e.g., a Nitinol.TM. tubing or sheet),
but the sizes of the cells or openings 234 in the body 228 and the
sections 230 and 232 can be varied to vary the flexibility of the
different body 228 or sections 230, 232. The section 232 can have
an annular distal edge 240 that functions as an open mouth. The
sections 230 and 232 can also have different size/porosity, and can
either be covered by a biocompatible polymer or left uncovered. One
example is to leave the section 232 uncovered, while covering
section 230. The uncovered section 232 can be incorporated with
other access catheters to facilitate the aspiration/suction
function. The proximal flow restrictor 112 can have a braided
configuration.
[0067] Third, the delivery wire 204 can have a deflected section
238 extending distally from the section 230 at an angle with
respect to the central longitudinal axis to the hub 210, which is
offset from the central longitudinal axis occupied by the delivery
wire 204. In this regard, the control arms 208 extend from the hub
210 towards the body 228 at different angles. The different angles
allows the expandable treatment member 202 to navigate the vascular
anatomy more easily, and also better facilitates the collection of
clots and particles by the expandable treatment member 202. In
addition, the different angles for the control arms 208 allow the
proximal opening of the expandable treatment member 202 to remain
open, and not to collapse, during the procedure. The different
angles also makes it easier for the control arms 208 to control the
diameter or staged deployment of the expandable treatment member
202 during the procedure.
[0068] The proximal flow restrictor 212 is configured so that it
can experience relative movement with respect to the expandable
treatment member 202. This is accomplished by not having a fixed
connection between the proximal flow restrictor 212 and the
delivery wire 204, and by allowing the proximal flow restrictor 212
to slide along the delivery wire 204. In other words, the
expandable treatment member 202 can move independent of the
proximal flow restrictor 212. This provides a more effective
capture and removal of the clot as described below.
[0069] In use, the device 200 is loaded inside a microcatheter 124,
which is delivered to a target location in a vessel with the device
200 housed therein using conventional delivery techniques that are
known to those skilled in the art. The distal end of the
microcatheter 124 can again be positioned proximal to, or inside,
the clot or embolus at the target location, and there is no need
for the microcatheter 124 to traverse the clot or embolus. The
device 200 can then be pushed distally out of the distal end of the
microcatheter 124 to expose first the expandable treatment member
202 and then later on the proximal flow restrictor 212. See FIG. 5.
The device 200 is then pulled back or withdrawn so that the
expandable treatment member 202 catches the clot. See FIG. 6A. When
the delivery wire 204 is pulled back and the expandable treatment
member 202 is pulled back with it, the proximal flow restrictor 212
can stay at the same location within the vessel, so that when the
annular distal edge 240 of the proximal flow restrictor 212
contacts the annular proximal edge or ring 222 of the body 228, and
further proximal pulling of the delivery wire 204 will cause the
expandable treatment member 202 to be pulled back into the
cylindrical section 230 so that the entire device 200 is removed
from the vessel. As a result, the entire clot or embolus can be
retained inside a cage defined by the expandable treatment member
202 and the proximal flow restrictor 212 during removal so as to
prevent dislodgement or disengagement of the clot. See FIG. 6B. The
expanded diameter of the annular proximal edge 222 is preferably
slightly smaller than the expanded diameter of the cylindrical
section 230 and its annular proximal edge 240 so that the
expandable treatment member 202 can be retained inside the
cylindrical section 230.
[0070] In addition, it is possible to provide the delivery wire 204
with a lumen that opens at an opening that is located inside the
proximal flow restrictor 212 (see FIGS. 13-14 below), so that
suction can be applied from the proximal end of the access guide
catheters or microcatheter 124 to pull smaller clots and particles
into the proximal flow restrictor 212 using suction force, and then
removed from the vessel.
[0071] Finally, the suction/aspiration action through the lumen of
the access devices and the encapsulation of the expandable
treatment member 102 (with clot engaged) can happen either
simultaneously or in sequence during the procedure.
[0072] FIGS. 7-9 illustrate another embodiment of a device 300 for
removing emboli and other luminal blockages. The device 300 is
similar to the device 200 in that it also has an expandable
treatment member 302, a delivery wire 304, a hub 310 and a proximal
flow restrictor 312 that correspond to the expandable treatment
member 202, delivery wire 204, hub 210 and proximal flow restrictor
212, respectively, for the second embodiment, except for a few
differences.
[0073] First, the expandable treatment member 302 has a different
configuration, and can be configured as any of the removal devices
disclosed in co-pending United States Publication No. 2015-0150672,
filed Jan. 16, 2015, whose entire disclosure is incorporated by
this reference as if set forth fully herein. For this reason, there
are no control wires 108/208.
[0074] Second, the proximal flow restrictor 312 can be essentially
the same as the proximal flow restrictor 212 in FIGS. 4-6.
[0075] Third, the hub 310 can function as a marker or stopper.
During the procedure, when the expandable treatment member 302 is
being pulled back, the expandable treatment member 302 will start
to pull the proximal flow restrictor 312 with it once the hub 310
reaches and engages the proximal end of the inside of the proximal
flow restrictor 312. At this stage, the entire (or portion of)
expandable treatment member 302 with its collected clot would
already be retained inside the proximal flow restrictor 312. Again,
suction force can be applied from the proximal end of the access
guide catheter or microcatheter to help pull all the clots/emboli
inside the proximal flow restrictor 312.
[0076] Again, the body of the expandable treatment member 302 and
the sections of the proximal flow restrictor 312 can all be laser
cut from the same material (e.g., a Nitinol.TM. tubing or sheet),
but the sizes of the cells or openings in the expandable treatment
member 302 and the proximal flow restrictor 312 can be varied to
achieve varying flexibilities. The proximal tapered portion on the
proximal flow restrictor 312 can be uncovered, while the straight
portion of the proximal flow restrictor 312 can be covered, to
achieve the desired suction effect and suction control.
[0077] As shown in FIG. 7, the clot can be caught on the surface
of, and between the cell spaces, of the expandable treatment member
302, and the expandable treatment member 302 pulled inside the
proximal flow restrictor 312 (see FIGS. 8-9) completely before the
entire system (microcatheter and device 300) is removed from the
blood vessel. Since the proximal flow restrictor 312 has no fixed
joint with the delivery wire 304, it can remain in a fixed location
with respect to the delivery wire 304 and the expandable treatment
member 302 so that the expandable treatment member 302 (with the
blood clot engaged thereon) can be pulled inside the proximal flow
restrictor 312. The expandable treatment member 302 can be pulled
into the proximal flow restrictor 312 until the hub 310 (acting as
a stopper) contacts the narrowed portion of the proximal section
332 of the proximal flow restrictor 312. The proximal portion of
the expandable treatment member 302 has a tapered configuration so
that it can fit into the narrowed proximal section 332. At this
time, the proximal flow restrictor 312 will move together with the
expandable treatment member 302 (and blood clot housed inside) when
the delivery wire 304 is pulled out. The device 300 can be pulled
inside a guide catheter for removal out of the vessel, or can be
removed out of the vessel without being pulled inside a guide
catheter first. Again, suction force can be applied from the
proximal end of the access guide catheter or microcatheter to help
pull all the clots/embolus inside the proximal flow restrictor
312.
[0078] FIGS. 10-12 illustrate another embodiment of a device 400
for removing emboli and other luminal blockages. The device 400 is
similar to the device 100 in that it also has an expandable
treatment member 402, a delivery wire 404, distal tip 406 and a
proximal flow restrictor 412 that correspond to the expandable
treatment member 102, delivery wire 104, distal tip 106 and
proximal flow restrictor 112, respectively, for the first
embodiment, except for a few differences.
[0079] First, the expandable treatment member 402 has a different
configuration, and has a distal section 440 that is essentially the
same as the conical body of the expandable treatment member 102.
However, the expandable treatment member 402 also has a proximal
section 442 that is also conically shaped with an apex 444 at its
proximal end and with its largest diameter portion coupled to the
largest-diameter portion of the distal section 440. The double
tapered configuration of the expandable treatment member 402 allows
its distal end to be softer and less traumatic, and also provides a
less stiff proximal end, which together allow for easier navigation
of the vessel anatomy. The distal expandable treatment portion 402
can be either entirely or partially covered by polymer materials to
block the blood flow (flow from distal portion of the vessel to
proximal portion of the vessel, so that the aspiration effect from
the access catheter and proximal flow restrictor will be more
effective).
[0080] Second, the proximal flow restrictor 412 can be essentially
the same as the proximal flow restrictor 212 in FIGS. 4-6.
[0081] Third, there is no hub 110 and no control wires 108/208.
[0082] Again, the body of the expandable treatment member 402 and
the sections of the proximal flow restrictor 412 can all be laser
cut from the same material (e.g., a Nitinol.TM. tubing or sheet),
but the sizes of the cells or openings in the expandable treatment
member 402 and the proximal flow restrictor 412 can be varied to
achieve varying flexibilities.
[0083] The clot can be engaged on the outside of the distal section
442 (see FIG. 11) and the expandable treatment member 402 can be
pulled inside the proximal flow restrictor 412 (see FIGS. 11 and
12) completely before the entire system (microcatheter and device
300) is removed from the blood vessel. Since the proximal flow
restrictor 412 has no fixed joint with the delivery wire 404, it
can remain in a fixed location with respect to the delivery wire
404 and the expandable treatment member 402 so that the expandable
treatment member 402 (with the blood clot engaged on its outer
surface) can be pulled inside the proximal flow restrictor 412. The
aspiration can be applied during the procedure through the lumen of
the access catheter or microcatheter and the proximal flow
restrictor as well.
[0084] FIGS. 13A, 13B, and 13C show some exemplary design
configurations for the braided proximal flow restrictor. The
proximal flow restrictor shown in FIGS. 13A-13C and 14A-14B can be
the same the proximal flow restrictor 212, although the principles
and concepts embodied in FIGS. 13A-13C and 14A-14B also apply to
the other proximal flow restrictors shown and described herein.
[0085] As shown in FIG. 13B, the proximal flow restrictor 212 can
have a central lumen 260 at the proximal end 262, a tapering
proximal portion 232, and a cylindrical distal portion 230. The
proximal portion 232 can be uncovered, and the distal portion 230
can be covered by biocompatible polymer materials. In use, suction
can be applied through the central lumen 260 from the access
catheters.
[0086] As shown in FIG. 13B, a push wire 264 can be connected to
the proximal portion 232 to operate the proximal flow restrictor
212. This design can be used or incorporated with other
commercially-available clot removal devices, and can also be used
or incorporated with an access catheter, guide catheter, DAC, or
microcatheter to apply suction during the clot removal
procedure.
[0087] As shown in FIG. 13C, a different central lumen structure
260a having a lumen can be connected to the proximal portion 232 to
operate the proximal flow restrictor 212. This design can be used
or incorporated with other commercially-available clot removal
devices, and can also be used or incorporated with an access
catheter, guide catheter, DAC, or microcatheter to apply suction
during the clot removal procedure.
[0088] FIGS. 14A and 14B show an exemplary application of the
proximal flow restriction feature. The proximal portion 232 can be
fully uncovered or partially uncovered, and the distal portion 230
can be covered by biocompatible polymer materials. In use, the
proximal flow restrictor 212 can be delivered to the target
location through a microcatheter or other access catheter 224. The
proximal central lumen 260 can be used to slide along a guidewire
or the push wire 264 of the clot retrieval device. Adjusting the
relative position/location of the microcatheter 224 with that of
the proximal flow restrictor 212, the proximal flow restrictor 212
can either allow proximal forward flow, or cut off the forward
flow. In the situation where forward flow is cut off, the suction
effect can be applied through the lumen of the microcatheter 224
for improved clot collection, retention and removal. For example,
when the push wire 264 connected to the proximal flow restrictor
212 is pulled back towards the access catheter or microcatheter
224, and the uncovered proximal portion 232 is completely covered
by the distal end of the access catheter or microcatheter 224 with
the covered distal portion 230 forming a seal with the distal end
of the access catheter or microcatheter 224, the forward flow is
totally cut off, and then the aspiration/suction can be applied
from the proximal end of the access catheter or microcatheter 224
to help retain and collect clots (as shown in FIG. 14B). From FIG.
14B, it is noted that the outer diameter of the access catheter 224
is less than the outer diameter of the fully expanded distal
portion 230, but that this seal can still be formed when the
proximal end of the distal portion 230 is pulled into the distal
opening of the access catheter 224 as the proximal part of the
distal portion 230 begins to compress and assume a tapered
configuration as the distal portion 230 is pulled into the access
catheter 224.
[0089] FIGS. 15A-15C illustrate a different embodiment of the
present invention, where the device 200 comprises only the flow
restrictor 212 and the push wire 264, and where the expandable
treatment member 202 is omitted. As shown in FIG. 15A, the distal
portion 230 is positioned proximal to the blood clot or embolus,
and the relative position/location of the access catheter 224 is
adjusted by operating the push wire 264, so that the proximal
portion 232 of the flow restrictor is covered by the distal end of
the access catheter 224. Aspiration is then applied to the lumen of
the access catheter 224 to suction or aspirate the blood clot into
the distal portion 230 and/or proximal portion 232 (see FIG. 15B),
and then the entire flow restrictor 212 (including the clot inside)
is pulled into the access catheter 224 (see FIG. 15C), and the
device 200 is removed out of the blood vessel.
[0090] As an alternative, if the embodiment shown in FIG. 13C is
used, the aspiration can be applied though the central lumen 260a,
instead of through the access catheter 224.
[0091] Thus, the embodiment of FIGS. 13C and 15A-15C show that the
expandable treatment member 202 can be omitted and the flow
restrictor 212 itself can be used to remove blood clots or embolus.
The structural arrangement of the flow restrictor 212 (uncovered
proximal portion 232 and covered distal portion 230) facilitates
this type of removal.
[0092] While the description above refers to particular embodiments
of the present invention, it will be understood that many
modifications may be made without departing from the spirit
thereof. The accompanying claims are intended to cover such
modifications as would fall within the true scope and spirit of the
present invention.
* * * * *