U.S. patent application number 13/802314 was filed with the patent office on 2013-09-26 for apparatus and methods for filtering emboli during precutaneous aortic valve replacement and repair procedures with filtration system coupled to distal end of sheath.
This patent application is currently assigned to NEXEON MEDSYSTEMS, INC.. The applicant listed for this patent is Mark C. Bates. Invention is credited to Mark C. Bates.
Application Number | 20130253570 13/802314 |
Document ID | / |
Family ID | 48040426 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130253570 |
Kind Code |
A1 |
Bates; Mark C. |
September 26, 2013 |
APPARATUS AND METHODS FOR FILTERING EMBOLI DURING PRECUTANEOUS
AORTIC VALVE REPLACEMENT AND REPAIR PROCEDURES WITH FILTRATION
SYSTEM COUPLED TO DISTAL END OF SHEATH
Abstract
Embodiments of the present invention provide apparatus and
methods for embolic filtering during percutaneous valve replacement
and repair procedures. Under one aspect, an apparatus comprises a
sheath and a filter. The sheath has proximal and distal ends and a
lumen therebetween. The distal end may be introduced into the
aortic arch via the peripheral arteries and ascending aorta, while
the proximal end may be disposed outside of the body. The lumen
permits percutaneous aortic valve replacement or repair
therethrough. The filter has a frame with an inlet and an outlet
and an emboli-filtering mesh attached to the frame. The inlet is
substantially spans the aortic arch in a region between the aortic
valve and the great arteries. The outlet is coupled to the distal
end of the sheath without leaving any gaps through which emboli
could pass and without obstructing the lumen at the distal end of
the sheath.
Inventors: |
Bates; Mark C.; (Encinitas,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bates; Mark C. |
Encinitas |
CA |
US |
|
|
Assignee: |
NEXEON MEDSYSTEMS, INC.
Charleston
WV
|
Family ID: |
48040426 |
Appl. No.: |
13/802314 |
Filed: |
March 13, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61613896 |
Mar 21, 2012 |
|
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|
Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2/2427 20130101;
A61F 2/011 20200501; A61F 2/013 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61F 2/01 20060101
A61F002/01 |
Claims
1. Apparatus for filtering emboli during a percutaneous aortic
valve replacement or repair procedure, the apparatus comprising: a
sheath having proximal and distal ends and a lumen therebetween,
the distal end being configured for introduction into the aortic
arch via the peripheral arteries and ascending aorta, the proximal
end being configured to be disposed outside of the body, the lumen
being sized to permit percutaneous aortic valve replacement or
repair therethrough; and a filter having a frame and an
emboli-filtering mesh attached to the frame, the frame having an
inlet and an outlet, the inlet being configured to substantially
span the aortic arch in a region between the aortic valve and the
great arteries, the outlet being coupled to the distal end of the
sheath without leaving any gaps through which emboli could pass and
without obstructing the lumen at the distal end of the sheath.
2. The apparatus of claim 1, further comprising a release line
coupled to the frame of the filter and passing out of the body
through the lumen, the release line being retractable from outside
of the body to detach the outlet of the filter from the distal end
of the sheath.
3. The apparatus of claim 2, wherein a groove is defined in the
lumen of the sheath and configured to receive the release line.
4. The apparatus of claim 2, further comprising a snare coupled to
the frame of the filter and passing out of the body through the
lumen, the snare being retractable from outside of the body to draw
the filter into the lumen.
5. The apparatus of claim 4, wherein a groove is defined in the
lumen of the sheath and configured to receive the snare.
6. The apparatus of claim 1, further comprising a snare coupled to
the frame of the filter and passing out of the body through the
lumen, the snare being retractable from outside of the body to
detach the outlet of the filter from the distal end of the sheath
and to draw the filter into the lumen.
7. The apparatus of claim 1, wherein the frame comprises a
generally cylindrical ring defining the inlet.
8. The apparatus of claim 7, wherein the frame further comprises a
generally cylindrical ring defining the outlet.
9. The apparatus of claim 8, wherein the frame further comprises a
plurality of struts between the rings defining the inlet and the
outlet.
10. The apparatus of claim 1, wherein the sheath has an inner
diameter of 18 French or less.
11. The apparatus of claim 10, wherein the outlet of the filter has
an outer diameter that is greater than the inner diameter of the
sheath.
12. The apparatus of claim 10, wherein the outlet of the filter has
an inner diameter that is greater than the inner diameter of the
sheath.
13. The apparatus of claim 1, the filter having a compressed state
and a deployed state, the apparatus further comprising a guidewire
and an introducer for use in percutaneously introducing the filter
and the distal end of the sheath into the aortic arch, the
introducer comprising: a tapered distal nose; a proximal end; a
guidewire lumen configured to receive the guidewire; and a recess
between the distal nose and the proximal end, the recess being
configured to receive the filter in the compressed state, the
introducer being configured for insertion within the lumen at the
distal end of the sheath and to retain the filter in the compressed
state within the recess, the introducer, the filter, and the distal
end of the sheath being percutaneously introducible into the aortic
arch by pushing the introducer over the guidewire via the
sheath.
14. The apparatus of claim 13, further comprising a control wire
coupled to the introducer, the control wire configured to advance
the introducer while the sheath is held in place, such advancement
of the introducer allowing the filter to expand from the compressed
state to the deployed state.
15. The apparatus of claim 14, the introducer being retrievable
through the outlet of the filter and the lumen of the sheath after
the filter expands to the deployed state by retracting the control
wire.
16. The apparatus of claim 13, wherein a portion of the sheath is
pre-curved to conform to the aortic arch, wherein the introducer
straightens the pre-curved portion of the sheath when inserted
therein.
17. A method of filtering emboli during a percutaneous aortic valve
replacement or repair procedure, the method comprising: providing a
sheath having proximal and distal ends and a lumen therebetween;
providing a filter having a compressed state and a deployed state,
the filter having a frame and an emboli-filtering mesh attached to
the frame, the frame having an inlet and an outlet, the inlet being
configured to substantially span the aortic arch in a region
between the aortic valve and the great arteries in the deployed
state, the outlet being coupled to the distal end of the sheath
without leaving any gaps through which emboli could pass and
without obstructing the lumen at the distal end of the sheath;
percutaneously introducing the distal end of the sheath into the
aortic arch; and expanding the filter from the compressed state to
the deployed state within the aortic arch.
18. The method of claim 17, further comprising detaching the outlet
of the filter from the distal end of the sheath by retracting a
release line coupled to the frame of the filter and passing out of
the body through the lumen.
19. The method of claim 18, further comprising retracting the
filter into the lumen with a snare coupled to the frame of the
filter and passing out of the body through the lumen.
20. The method of claim 17, further comprising: providing a
guidewire and an introducer having a guidewire lumen configured to
receive the guidewire, the introducer having a recess configured to
receive the filter in the compressed state; compressing the filter
to the compressed state within the recess of the introducer;
inserting the introducer into the lumen at the distal end of the
sheath and retaining the filter in the compressed state within the
recess and between the introducer and the sheath; and
percutaneously introducing the introducer, the filter, and the
sheath into the aortic arch by pushing the introducer over the
guidewire via the sheath.
21. The method of claim 20, wherein said expanding comprises
advancing the introducer while maintaining the sheath in place so
as to expose the filter and allow the filter to expand from the
compressed state to the deployed state.
22. The method of claim 21, further comprising retrieving the
introducer through the outlet of the filter and the lumen of the
sheath after the filter expands to the deployed state.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority of U.S.
Provisional Application Ser. No. 61/613,896, filed Mar. 21,
2012.
FIELD OF THE INVENTION
[0002] This application generally relates to filtering emboli
during interventional procedures, particularly percutaneous aortic
valve replacement and repair procedures.
BACKGROUND OF THE INVENTION
[0003] The recent development of prosthetic valves that can be
placed through a catheter into the heart without thoracotomy
represents a significant advance in the field of cardiovascular
medicine. Early results are very promising and overall reduction in
mortality has been achieved with transcatheter aortic valve
implantation (TAVI) in high surgical risk patients when compared to
medical therapy. One of the limitations for wide acceptance of this
technology is the inherent risk of embolic complication during
valve access, dilation and implantation. For example, each
guidewire, introducer, balloon, cutter, or prosthetic valve that is
introduced into the heart via the peripheral arteries and the
ascending aorta may inadvertently dislodge one or more emboli,
e.g., fragments of unstable plaque, irregular atherosclerotic
calcified lesions, or mural thrombus, from the aortic arch, the
area surrounding the aortic valve, or the chambers of the heart.
The great vessels, which branch off the greater curve of the aortic
arch, may transport such emboli to vulnerable locations like the
eyes and brain causing stroke or blindness. In addition embolic
material can flow past the arch and occlude vessels to the spinal
cord causing paralysis, to the bowel causing life threatening
mesenteric ischemia/infarction, or to the renal vessels causing
kidney failure, for example.
[0004] Numerous filters have been developed with the purpose of
preventing emboli from entering the great vessels, particularly the
carotid artery. For example, U.S. Pat. No. 8,062,324 to Shimon et
al. describes a filter that is supported by a skeleton having a
horizontal plane, and that is pressed against the upper portion of
the aortic arch by one or more bows so as to filter any blood
passing into the great arteries. Shimon describes that the filter
may be inserted using a catheter. However, Shimon does not disclose
how to remove the filter in such a manner as to prevent filtered
emboli from re-entering the blood stream, nor so as to prevent
additional emboli from being dislodged by the edges of the skeleton
or the bows during removal. Additionally, if additional devices are
percutaneously introduced via the ascending aorta, such devices may
scrape against the filter and thus potentially cause trauma to the
aortic wall or dislodge emboli from the filter. In any such device
designed to deflect particles by resting on the greater curve of
the arch there is also the issue of device interaction and
entanglement since the typical valve is a high profile stiff
catheter that will have significant outward bias along the greater
curve during advancement across the arch. This type of interaction
could result in marriage of the devices together with catastrophic
consequences as well as product incompetence if it folds up during
catheter exchanges.
[0005] U.S. Pat. No. 8,052,713 to Khosravi et al. describes an
apparatus for filtering emboli from the ascending aorta, that
includes a thin, flexible, blood permeable sac having a mouth
defined by a support hoop affixed to a guide wire, and a relatively
short delivery sheath with a tapered proximal nose and a square
distal end. Khosravi describes that the sac and support hoop may be
disposed in the delivery sheath, which may be introduced to the
ascending aorta via a guidewire. Khosravi describes that the sac
may be deployed in the ascending aorta by retracting the support
hoop proximally relative to the delivery sheath (in the direction
away from the tapered nose), which draws the hoop out of the sheath
and allows the sac to open across the aorta, proximal of the
brachiocephalic trunk. Khosravi describes that the sac may be
retrieved by advancing the support hoop back into the delivery
sheath to collapse the sac, and then retracting the delivery sheath
back down the ascending aorta. However, the square distal end of
the delivery sheath may scrape the aortic arch as it is retrieved
and thus potentially loosen additional occlusive material, such as
emboli, from the aortic arch. Additionally, because the sac spans
the aorta when deployed, the sac may impede the physician's ability
to percutaneously introduce other devices to the aorta because such
devices may become trapped in the sac, or alternatively may create
a gap between the edge of the sac and the aortic wall, thus
providing an avenue for emboli or other occlusive material to
bypass the sac.
[0006] Thus, there is a need in the art for embolic filters that
may be deployed in the ascending aorta, that safely sequester any
filtered occlusive material, such as emboli or thrombus, are shaped
to avoid dislodging additional when retrieved, provide protection
during all stages of the procedure and allow percutaneous valve
replacement or repair procedures to be performed via the peripheral
arteries and the ascending aorta without increasing the profile of
the delivery sheath, which already may be at the limits of femoral
vessel tolerance.
SUMMARY OF THE INVENTION
[0007] Embodiments of the present invention provide apparatus and
methods for filtering occlusive material such as emboli or thrombus
during percutaneous valve replacement and repair procedures. Such
apparatus and methods may safely sequester any filtered emboli, are
shaped to avoid dislodging additional emboli when retrieved, are
fully compatible with percutaneous valve replacement or repair
procedures performed via the peripheral arteries and the ascending
aorta, and do not require use of a delivery sheath larger than
those already adopted for such percutaneous procedures (e.g., 18
French).
[0008] Under one aspect of the present invention, an apparatus for
filtering emboli during a percutaneous aortic valve replacement or
repair procedure comprises a sheath and a filter. The sheath has
proximal and distal ends and a lumen therebetween. The distal end
is configured for introduction into the aortic arch via the
peripheral arteries and ascending aorta, while the proximal end
being configured to be disposed outside of the body. The lumen is
sized to permit percutaneous aortic valve replacement or repair
therethrough. The filter has a frame and an emboli-filtering mesh
attached to the frame. The frame has an inlet and an outlet. The
inlet is configured to substantially span the aortic arch in a
region between the aortic valve and the great arteries. The outlet
is coupled to the distal end of the sheath without leaving any gaps
through which emboli could pass and without obstructing the lumen
at the distal end of the sheath.
[0009] In some embodiments, a release line is coupled to the frame
of the filter and passes out of the body through the lumen, and is
retractable from outside of the body to detach the outlet of the
filter from the distal end of the sheath. A groove may be defined
in the lumen of the sheath and configured to receive the release
line. A snare may be coupled to the frame of the filter and pass
out of the body through the lumen, and may be retractable from
outside of the body to draw the filter into the lumen. A groove may
be defined in the lumen of the sheath and configured to receive the
snare.
[0010] In an alternative embodiment, a snare may be coupled to the
frame of the filter and pass out of the body through the lumen, and
may be retractable from outside of the body to both detach the
outlet of the filter from the distal end of the sheath and to draw
the filter into the lumen.
[0011] In some embodiments, the frame comprises a distal, generally
cylindrical ring defining the inlet and/or a proximal, generally
cylindrical ring defining the outlet. The frame further may
comprise a plurality of struts between the rings defining the inlet
and the outlet.
[0012] In some embodiments, the sheath has an inner diameter of 18
French or less. The outlet of the filter may have an outer diameter
that is greater than the inner diameter of the sheath.
Alternatively, the outlet of the filter may have an inner diameter
that is greater than an inner diameter of the sheath.
[0013] In some embodiments, the filter has a compressed state and a
deployed state. The apparatus may further include a guidewire and
an introducer for use in percutaneously introducing the filter and
the distal end of the sheath into the aortic arch. The introducer
may include a tapered distal nose, a proximal end, a guidewire
lumen configured to receive the guidewire, and a recess between the
distal nose and the proximal end. The recess may be configured to
receive the filter in the compressed state. The introducer may be
configured for insertion within the lumen at the distal end of the
sheath when the filter is expanded and coupled distally. The filter
may be crimped into the recess during the manufacturing process and
retained the compressed state within the recess. The introducer,
the filter, and the distal end of the sheath may be percutaneously
introducible into the aortic arch by pushing the introducer and
sheath in their married position (or coupled together) over the
guidewire. A control wire may be coupled to the introducer, and the
control wire may be configured to advance the introducer while the
sheath is maintained in position, allowing for slow deliberate
expansion of the filter and avoiding traumatic sudden expansion and
advancement out the end of the sheath. The introducer may be
retrievable through the outlet of the filter and the lumen of the
sheath after the filter expands to the deployed state by retracting
the control wire. A portion of the sheath may be pre-curved to
conform to the aortic arch, and the introducer may straighten the
pre-curved portion of the sheath when inserted therein.
[0014] Under another aspect of the present invention, a method of
filtering emboli during a percutaneous aortic valve replacement or
repair procedure may include providing a sheath having proximal and
distal ends and a lumen therebetween; and providing a filter
coupled to the distal end of the sheath. The filter may have a
compressed state and a deployed state, a frame, and an
emboli-filtering mesh attached to the frame. The frame may have an
inlet and an outlet, the inlet being configured to substantially
span the aortic arch in a region between the aortic valve and the
great arteries in the deployed state. The outlet of the filter is
coupled to the distal end of the sheath within the aortic arch
without leaving any gaps through which emboli could pass and
without obstructing the lumen at the distal end of the sheath. The
filter may be advanced through the previously positioned sheath via
an introducer with a recess that will accommodate the filter and a
control wire mechanism coupled to the introducer may be used to
control expansion during deployment of the filter.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1A illustrates a perspective view of a catheter for use
in percutaneous aortic valve replacement or repair including an
embolic filter and sheath assembly in an expanded configuration,
according to some embodiments of the present invention.
[0016] FIG. 1B illustrates a detailed perspective view of the
embolic filter and sheath assembly of FIG. 1A.
[0017] FIG. 2A illustrates a perspective view of an exemplary
coupling/release mechanism that may be used with the embolic filter
and sheath assembly of FIGS. 1A-1B.
[0018] FIG. 2B illustrates a perspective view of the distal end of
an exemplary sheath that may be used with the embolic filter and
sheath assembly of FIGS. 1A-1B.
[0019] FIG. 2C illustrates a plan view of a pre-curved sheath that
optionally may be used with the embolic filter and sheath assembly
of FIGS. 1A-1B.
[0020] FIGS. 3A-3F illustrate cross-sectional views of an
introducer that may be used with the embolic filter and sheath
assembly of FIGS. 1A-1B.
[0021] FIG. 4 illustrates steps in a method of using the embolic
filter and sheath assembly of FIGS. 1A-1B and the introducer of
FIGS. 3A-3F in an aortic arch during a percutaneous procedure.
[0022] FIGS. 5A-5C illustrate cross-sectional views of the embolic
filter and sheath assembly of FIGS. 1A-1B and the introducer of
FIGS. 3A-3F in an aortic arch during various steps of the method of
FIG. 4.
[0023] FIGS. 6A-6C illustrate perspective views of an exemplary
release mechanism that may be used to remove the embolic filter and
sheath assembly of FIGS. 1A-1B.
[0024] FIGS. 7A-7I illustrate perspective views of another
exemplary release mechanism that may be used to remove the embolic
filter and sheath assembly of FIGS. 1A-1B.
[0025] FIGS. 8A-8C illustrate perspective views of another
exemplary release mechanism that may be used to remove the embolic
filter and sheath assembly of FIGS. 1A-1B.
[0026] FIGS. 9A-9D illustrate perspective views of the operation of
an exemplary release mechanism that may be used to remove the
embolic filter and sheath assembly of FIGS. 1A-1B.
DETAILED DESCRIPTION
[0027] Embodiments of the invention provide embolic filters that
readily may be used during percutaneous aortic valve replacement
and repair procedures and that overcome the above-noted
shortcomings of previously-known systems. The inventive filters may
be coupled to the distal end of a sheath suitable for percutaneous
delivery into the aorta, e.g., an 18 F sheath, and then compressed
and mounted on an introducer that has a tapered nose and is
disposed in the distal end of the sheath. The sheath, introducer,
and compressed filter then are introduced to the aortic arch via
the peripheral arterial system (e.g., femoral artery) and ascending
aorta. The filter then is deployed from the distal end of the
sheath by advancing the introducer relative to the sheath such that
the filter expands to a deployed configuration at a location
upstream of the great arteries, and the introducer then removed via
the lumen of the sheath. The filter is securely coupled to the
distal end of the sheath in such a manner that the full lumen of
the sheath may be used for additional percutaneous procedures,
e.g., to percutaneously introduce a guidewire, introducer, balloon,
cutter, and/or prosthetic valve to the heart via the sheath. Then,
when the percutaneous procedure is complete and any other devices
have been removed from the lumen of the sheath, a release line may
be retracted from outside of the body to detach the filter from the
end of the sheath, and a snare on the filter may be used to close
the filter and retract the filter and any captured emboli into the
lumen of the sheath after venting the sheath. The sheath then may
be removed by refracting it from the ascending aorta and peripheral
arterial system. As such, the inventive filters do not interfere
with other percutaneously introduced devices, are compatible with
18 French sheaths, safely sequester filtered emboli when removed,
and are shaped to avoid dislodging additional emboli when
removed.
[0028] First, an overview of a catheter system including the
inventive embolic filter and sheath assembly will be described.
Then, further details will be provided on the construction of the
sheath and embolic filter, respectively. Lastly, some alternative
embodiments will be described.
[0029] FIG. 1A illustrates percutaneous catheter 100 including
sheath 110, filter 120, and handle 130. Sheath 110 generally is in
the form of an elongated tube having proximal end 111 and distal
end 112, with lumen 113 therebetween. Preferably, sheath 110 has a
diameter suitable for percutaneous use, e.g., has an inner diameter
of 18 French or smaller. In some embodiments, sheath 110 includes
reinforcing rings of metal or polymer to inhibit collapse of the
sheath when curved around the aortic arch.
[0030] Filter 120 includes a frame and an emboli-filtering mesh
attached to the frame. The frame defines an inlet and an outlet of
filter 120. Preferably, the inlet has lateral dimensions
approximately equal to those of the aortic arch between the aortic
valve and the great arteries, where the filter will be deployed, so
that the emboli-filtering mesh will filter substantially all of the
blood passing through the aorta and remove emboli therefrom. The
outlet of filter 120 is detachably coupled to distal end 112 of
sheath 110, preferably without any gaps therebetween that would
allow emboli to pass. The outlet of filter 120 also preferably has
an inner lumen with a diameter that is at least as large as the
inner diameter of sheath 110, so that filter 120 does not obstruct
the lumen at the distal end of the sheath, thus allowing a
physician to perform percutaneous procedures via the sheath without
interference from filter 110.
[0031] Handle 130 is coupled to proximal end 111 of sheath 110, and
includes release line 131 via which filter 120 may be detached from
distal end 112 of sheath 110 while deployed, snare control 132 via
which filter 120 may be retrieved by retracting the filter into the
lumen at the distal end 112 of sheath 110, and various additional
ports and passages, generally designated 139, via which a physician
may introduce additional percutaneous devices. Handle 130 also may
include a controller line (not shown) for controlling an introducer
that may be used to deploy the filter, such as described below with
reference to FIGS. 3A-3C.
[0032] Note that as used herein with reference to elements for
insertion into the body, the term "distal" refers to the end that
is inserted into the body first, e.g., the leading end of sheath
110 or filter 120 during advancement into the body, whereas the
term "proximal" refers to the opposite end.
[0033] FIG. 1B illustrates a perspective view of an assembly
including filter 120 and distal end 112 of sheath 110. Filter 120
includes frame 121 and mesh 122 attached thereto, e.g., by sutures,
adhesives, dip molding, laser bonding, sandwich layers on each side
of the struts melted or glued together, heat setting or the like.
In the illustrated embodiment, frame 121 includes first and second
generally cylindrical rings 123, 124. First ring 123 defines the
inlet of filter 120, which as noted above preferably is of similar
dimension to the ascending aorta in the region where the filter is
to be deployed, e.g., between the aortic valve and the great
arteries, so as to securely seat against the aortic wall and
prevent emboli from slipping past the filter. Second ring 124
defines the outlet of filter 120, which is of similar dimension to
distal end 112 of sheath 110. Specifically, second ring 124 is
sized such that it does not obstruct lumen 113 of sheath 110 at
distal end 112, so that the physician may conduct percutaneous
procedures through lumen 113 without interference from filter 120.
For example, second ring 124 may have an inner diameter that is
equal to, or larger than, the inner diameter of lumen 113, and/or
may have an outer diameter that is larger than the inner diameter
of lumen 113.
[0034] First and second rings 123, 124 preferably are formed of a
shape memory material, e.g., a metallic alloy such as Nitinol,
stainless steel, MP35N, elgiloy or a shape memory polymer such as
polyurethane or a block copolymer thereof, polyethylene
terephthalate or a block copolymer thereof, polyethylene oxide or a
block copolymer thereof, and the like. First and second rings 123,
124 respectively include struts 125, 126, which may be sinusoids,
zigzags, or other suitable shape that permits rings 123, 124 to be
radially compressed into a compressed state for delivery and to
return to a deployed state when expanded in the aortic arch.
Optionally, frame 121 includes struts 127 that extend between first
and second rings 123, 124. Struts 127 may have any suitable shape,
including linear, sinusoids, or curves, and may extend within the
interior surface of mesh 122 and/or may extend outside of the
exterior surface of mesh 122. In other embodiments, only mesh 122
extends between first and second rings 123, 124, allowing the rings
to freely move relative to one another so as to lessen the effect
of blood-flow-induced torque that otherwise may cause filter 120 to
tilt relative to sheath 110 and thus form a gap through which
emboli may pass.
[0035] Mesh 122 preferably covers the entire outer surface of
filter 120, including first and second rings 123, 124, such that
substantially all of the blood in the aorta flows through filter
120 with no gaps. Mesh 122 has a surface area and pore size
suitable to allow a sufficient volume of blood to pass therethrough
to maintain the patient's blood pressure in a normal range, and
also to avoid pressure buildup that otherwise may rupture mesh 122.
Mesh 122 may include any suitable material known in the art,
including a fabric, polymer, or flexible metal having pores of
appropriate size to filter emboli having diameters of, e.g., 20
.mu.m or greater, or 50 .mu.m or greater, or 100 .mu.m or greater,
or 150 .mu.m or greater, or 200 .mu.m or greater. In one
illustrative embodiment, mesh 122 is a polyurethane film of
thickness 0.0003 inches to about 0.0030 inches and having holes
defined therethrough, e.g., circular, square, or triangular holes
in a suitable size and density to permit substantially the entire
aortic blood flow to pass therethrough without a detrimental amount
of resistance.
[0036] FIG. 2A illustrates an exemplary coupling/release mechanism
that may be used to couple and subsequently detach filter 120 from
distal end 112 of sheath 110 and pull the filter into lumen 113 of
the sheath. Second ring 124 of filter 120 is coupled to a release
line 131 that passes out of the patient's body through sheath 110
via lumen 135 and into handle 130 as illustrated in FIG. 1A.
Release line 131 is coupled to, or includes, a wire or suture 133
that loops through sinusoids 126 of second ring 124, as well as
through sheath elements 134 which are embedded in distal end 112 of
sheath 110. Tension in wire/suture 133 causes second ring 124 to
securely seat against distal end 112. As described in greater
detail below with reference to FIGS. 6A-6C, retraction of release
line 131 from outside the body may break wire/suture 133, releasing
such tension and detaching ring 124 from distal end 112. In some
embodiments, wire/suture 133 and/or release line 131 is formed of a
relatively stiff material such as stainless steel or a shape memory
alloy, so as to maintain a relatively large amount of tension to
retain second ring 124 against distal end 112. In other
embodiments, wire/suture 133 and/or release line 131 may be formed
of a relatively flexible material such as fiber or polymer, so that
wire/suture 133 may easily be broken, thus detaching ring 124 from
distal end 112. Sheath elements 134 may be formed of a relatively
stiff material such as stainless steel or a shape memory alloy.
Other possible configurations for sheath elements 134 are described
further below with reference to FIGS. 7B-7C. Note also that instead
of looping wire/suture 133 through sinusoids 126 as described with
reference to FIG. 2A, a fabric ring may be coupled to second ring
124 and wire/suture 133 woven therethrough instead, such as
described further below with reference to FIGS. 7A-7I.
[0037] As illustrated in FIG. 2A, second ring 124 also is coupled
to snare 132, which is coupled to, or includes, wire 135 that loops
about second ring 124 and passes out of the patient's body through
groove 136 and into handle 130 as illustrated in FIG. 1A.
Retracting snare 132 via handle 130 first causes wire 135 to
radially contract second ring 124, and then pulls filter 120 into
lumen 113 sheath 110 for removal from the body. Such a process is
described further below with reference to FIGS. 6A-6C. In some
embodiments, wire 135 and/or snare 132 is formed of a relatively
stiff material such as stainless steel or a shape memory alloy, so
as to impose relatively large compressive forces on second ring
124.
[0038] FIG. 2B illustrates distal end 112 of sheath 110 in greater
detail. Release line 131 (not shown in FIG. 2B) may be disposed
within lumen 135, and snare 132 (not shown in FIG. 2B) may be
disposed within groove 136 defined in the inner surface 118 of
sheath 110. Such an arrangement may inhibit interference between
release line 131 or snare 132 and any devices that may be
percutaneously introduced to the patient via sheath 110. In
particular, groove 136 may be of such a depth that snare 132 does
not reduce the effective inner diameter of lumen 113, thus allowing
the physician to make full use of lumen 113 without obstruction
during a percutaneous procedure. Alternative embodiments described
below with reference to FIGS. 8A-9D use a combined snare/release
mechanism that uses only a single groove through which filter 120
may be detached from distal end 112 of sheath 110 and pulled into
lumen 113, thus further simplifying construction of sheath 110 and
reducing the possibility of interference with instruments during
the percutaneous procedure.
[0039] Optionally, sheath 110 is pre-curved to follow the curve of
the patient's aortic arch, such as illustrated in FIG. 2C where
bend 119 is disposed proximal of distal end 112. Pre-curving sheath
110 as such may help to reduce tension the aortic arch may
otherwise place on sheath 110 and/or filter 120 when deployed
therein. Preferably, inserting introducer 300 (described further
below with reference to FIGS. 3A-3F) into sheath 110 temporarily
straightens bend 119; later, when introducer 300 is removed from
sheath 110, bend 119 returns and generally follows the curve of the
patient's aortic arch.
[0040] FIG. 3A illustrates an introducer 300 that may be used to
introduce and deploy filter 120 into a patient's aortic arch.
Introducer 300 includes tapered distal nose 301, proximal end 302,
a guidewire lumen 303 configured to receive a guidewire (not
illustrated in FIG. 3A), and a recess 304 between the distal nose
and proximal end having cover 305 disposed thereover. Recess 304 is
configured to receive filter 120 in a compressed state. For
example, as illustrated in FIG. 3B, compressed state filter 120'
may include radially compressed first ring 123', radially
compressed second ring 124', folded mesh 122', and compressed
struts 127'. Section 302 of introducer 300 may be tapered as shown
to accommodate tilting of compressed second ring 124' caused by
coupling of that ring to distal end 112 of sheath 110. Recess 304
of introducer 300 may be configured to have a length approximately
equal to the length of compressed state filter 120', and an outer
diameter (defined by the outer surface of cover 305) suitable for
percutaneous insertion. Cover 305 may retain sliding of filter 120'
in the proximal or lateral directions. Radiopaque markers (not
shown) may be provided on introducer 300 and/or on filter 120/120'
so as to assist the physician in properly positioning introducer
300 and filter 120/120' in the aortic arch.
[0041] As illustrated in FIG. 3B, when introducer 300 is inserted
into lumen 113 of sheath 110, tapered nose 301 and cover 305
provide a smooth surface when introducer 300, compressed state
filter 120', and distal end 112 of sheath 110 are percutaneously
advanced into the aortic arch by pushing introducer 300 over the
guidewire (not illustrated) via sheath 110. Preferably, introducer
300 also includes control line 306 which is coupled to proximal end
302 and which passes out of the body via lumen 113 of sheath 110
and an appropriate port (not illustrated). Control line 306 may be
used to advance introducer 300 while sheath 110 is held in place so
as to allow compressed state filter 120' to expand into the
deployed state, e.g., filter 120 illustrated in FIGS. 1A-1B.
[0042] For example, FIG. 3C illustrates the relative positioning of
introducer 300, filter 120, and sheath 110 when introducer 300 is
partially advanced out of lumen 113 of sheath 110 by advancing
control line 306 relative to sheath 110. As introducer 300 is moved
distally, partially deployed struts 127'' of partially deployed
filter 120'' bow outwardly as the struts are no longer retained
beneath cover 305. At the illustrated stage of deployment, first
ring 123' of filter 120'' is retained in the compressed state
within recess 304 and beneath cover 305. However, second ring 124
of filter 120'' is no longer in the compressed state because it is
no longer within recess 304 or beneath cover 305.
[0043] As illustrated in FIG. 3D, when introducer 300 is further
advanced out of lumen 113 of sheath 110 via control line 306, first
ring 123 of filter 120 opens to a fully deployed state, as do
struts 127, because first ring 123 is no longer within recess 304
or beneath cover 305. Then, as illustrated in FIG. 3E, introducer
300 may be removed via lumen 113 by retracting control line 306.
Further details on the use of introducer 300 to deploy filter 120
are described in greater detail below with reference to FIGS. 4 and
5A-5C.
[0044] A method of percutaneously deploying filter 120 and distal
end of sheath 112 in the aortic arch for filtering emboli during a
percutaneous procedure will now be described with reference to FIG.
4, which illustrates steps in method 400, and FIGS. 5A-5C, which
illustrate the relative positions of components of apparatus 100
and a patient's heart.
[0045] Method 400 includes providing a sheath having proximal and
distal ends and a lumen therebetween (step 410), for example sheath
110 illustrated in FIGS. 1A-2C.
[0046] A filter is also provided having a compressed state and a
deployed state, a frame having an inlet sized to span the aortic
arch in the deployed state and an outlet, and an emboli-filtering
mesh attached to the frame (step 420), for example filter 120/120'
illustrated in FIGS. 1A-1B.
[0047] The filter then may be coupled to the distal end of the
sheath (step 430), e.g., with a wire/suture such as illustrated in
FIG. 2A. The filter then may be compressed within the recess of an
introducer (step 440), e.g., as described above with reference to
FIGS. 3A-3F.
[0048] The introducer, the filter, and the distal end of the sheath
then may be introduced into the aortic arch (step 450). For
example, introducer 300 may be inserted into lumen 113 at distal
end 112 of sheath 110, and compressed state filter 120' may be
crimped into recess 304 of the introducer and covered with cover
305. Then, as illustrated in FIG. 5A, assembly 300, 120', 112
(filter 120' not shown in FIG. 5A) may be percutaneously advanced
into aortic arch 510 of a patient's heart 500 over guidewire 510
through guidewire lumen 303 of introducer 300, by pushing on the
proximal end 111 of sheath 110 from outside the patient's body.
Assembly 300, 120', 112 (filter 120' not shown in FIG. 5A) is
preferably pushed to a location in aortic arch 501 that is between
aortic valve 502 and great arteries 503.
[0049] Referring again to FIG. 4, the filter then may be expanded
from the compressed state to the deployed state within the aortic
arch (step 460). For example, as illustrated in FIG. 5B, introducer
300 may be advanced from outside the patient's body, e.g., using
control line 306 described above with reference to FIGS. 3A-3F,
while the position of sheath 110 is maintained. Such advancement of
introducer 300 allows compressed state filter 120' to expand to
deployed state filter 120 which, as illustrated in FIG. 5B,
substantially spans the aortic arch between aortic valve 502 and
the great arteries 503. In particular, control line 306 maintains
the relative positioning of compressed second (proximal) ring 124'
of compressed filter 120' and introducer 300, thus facilitating
slow, deliberate expansion of filter 120 as sheath 110 is retracted
and avoiding traumatic sudden expansion of filter 120 out of sheath
110. Introducer 300 then may be removed via lumen 113, e.g., by
retracting control line 306 from outside the body, leaving the
lumen of sheath 110 unobstructed, as illustrated in FIG. 5C.
[0050] Referring again to FIG. 4, a percutaneous procedure may be
performed on the aortic valve through the lumen of the sheath
(470). Such percutaneous procedures may involve, for example,
percutaneously introducing a guidewire, introducer, balloon,
cutter, and/or prosthetic valve to the heart through sheath 110 and
filter 120 as illustrated in FIG. 5C. For example, the physician
may implant a prosthetic aortic valve that is specifically
configured for percutaneous delivery via an 18 French sheath, such
as the COREVALVE.TM. device manufactured by Medtronic, or the
SAPIEN.TM. device manufactured by Edwards Lifesciences.
Advantageously, filter 120, tensioning lines 131, and snare 132 do
not obstruct lumen 113 of sheath 110, so that the physician may
perform any desired percutaneous procedure using the full diameter
of sheath 110. Filter 120 captures any emboli that may be freed
from the region surrounding the aortic valve during such procedure,
thus reducing the patient's risk of stroke from embolization.
[0051] An illustrative method of removing filter 120 and any
filtered emboli from the body will now be described with reference
to FIGS. 6A-6D. As illustrated in FIG. 6A, release line 131 may be
retracted from outside the body, causing breakage of suture/wire
133' and allowing free end 133'' of broken suture/wire 133' to come
loose from sheath elements 134 and sinusoids 126 of second ring
124, thus detaching filter 120 from sheath 110. Then, as
illustrated in FIG. 6B, retraction of snare 132 in the proximal
direction causes wire 135 to radially compress proximal end 129 of
second ring 124, resulting in partially compressed second ring 124'
having a generally hourglass shape as illustrated in FIG. 6B, and
to begin to retract partially compressed second ring 124' into
lumen 113 of sheath 110. Further retraction of snare 132 in the
proximal direction pulls proximal end 129 of second ring 124'''
fully into lumen 113 of sheath 110 as illustrated in FIG. 6C.
Further retraction of snare 132 in the proximal direction retracts
the entirety of filter 120, including any emboli therein, into a
compressed removal state within lumen 113 of sheath 110. Sheath 110
then may be withdrawn from the body by pulling the sheath in the
proximal direction. Advantageously, sheath 110 does not have any
sharp corners that would potentially loosen emboli during such
removal. Additionally, any emboli within filter 120 advantageously
remain within lumen 113 during the removal process, so as to
further reduce the patient's chance of stroke due to
embolization.
[0052] FIGS. 7A-7I illustrate an alternative mechanism that may be
used to release filter 120 from sheath 110 prior to retraction with
snare 132 into lumen 113. Referring to FIG. 7A, second ring 124 of
filter 120 is coupled via sutures, adhesive, or the like to fabric
ring 701, which is a ring of flexible, biocompatible fabric having
a length sufficiently short to avoid folding-in of the fabric
during device or introducer retraction. Wire/suture 733 is stitched
or woven through fabric ring 701 and sheath elements 734, which
secures filter 120 to distal end 112 of sheath 110. Sheath elements
734 may be closed arches having both ends embedded in distal end
112 of sheath 110, such as illustrated in FIGS. 7A-7B, or may have
a construction similar to the eye of a needle, with an aperture
spaced some distance away from distal end 112, such as illustrated
in FIG. 7C.
[0053] The two ends of wire/suture 733 are coupled to locking
mechanism 732, which in the illustrated embodiment includes a
"J"-shaped hook 735 that is coupled to release line 731 within
lumen 736. Hook 735 may be formed of a shape memory alloy such as
described above. As can be seen in FIG. 7A, a first end of
wire/suture 733 is coupled to one side of hook 735, which is
disposed within pocket 737 defined within distal end 112 of sheath
110, while the second end of wire/suture 733 is coupled to the
other side of hook 735. As such, hook 735 securely retains the ends
of wire/suture 733 and thus maintains coupling between filter 120
and sheath 110 until hook 735 is retracted via release line 731.
Further details on coupling wire/suture 733 to hook 735 are
provided further below with reference to FIGS. 7D-7G, and further
details on detaching filter 120 from sheath 110 using wire/suture
711, hook 735, and release line 731 are provided further below with
reference to FIGS. 7H-7I.
[0054] Referring now to FIG. 7D, hook 735 includes short end 738,
and long end 739. Short end 738 may be moved relative to distal end
112 of sheath 110 by pushing or retracting release line 731, which
may be integrally formed with hook 735, e.g., using a shape memory
alloy. As illustrated in FIG. 7E, first end 741 of wire/suture 733
may include a loop through which short end 738 of hook 735 fits,
while second end 742 of wire/suture 733 may include a loop through
which long end 739 of hook 735 fits. FIG. 7F illustrates motion of
hook 735 in the proximal direction when release line 731 is
partially retracted, during which short end 738 of hook 735 becomes
disposed in pocket 737 defined at distal end 112 of sheath 110. As
illustrated in FIG. 7G, such motion of hook 735 secures the first
and second ends 741, 742 of wire/suture 733, which as discussed
above securely couples filter 120 to sheath 110. FIG. 7H
illustrates further motion of hook 735 in the proximal direction
when release line 731 is more fully retracted, during which short
end 738 of hook 735 is pulled out of pocket 737 and drawn into
release line lumen 736. As illustrated in FIG. 71, such motion of
hook 735 releases the first and second ends 741, 742 of suture,
which as discussed above detaches filter 120 from sheath 110.
[0055] FIGS. 8A-8C illustrate another alternative mechanism that
may be used to release filter 120 from sheath 110 prior to
retraction into lumen 113. In this embodiment, a combined
release/retraction mechanism permits both functions to be performed
using only a single mechanism, thus simplifying the design of
sheath 110 by obviating the need to provide multiple separate
grooves or lumens to control release and retraction of filter 120.
Referring to FIG. 8A, second ring 124 of filter 120 is coupled via
sutures, adhesive, or the like to fabric ring 801, which is a ring
of flexible, biocompatible fabric having a length sufficiently
short to avoid folding-in of the fabric during device or introducer
retraction. Wire/suture 833 is stitched or woven through fabric
ring 801 and sheath elements 834, which secures filter 120 to
distal end 112 of sheath 110. Wire/suture 833 passes through
locking mechanism 832, which in the illustrated embodiment includes
an release segment 835 configured to break wire/suture 833 by
applying electrical current or voltage thereto.
[0056] As illustrated in FIGS. 8B-8C, in which filter 120 and
sheath 110 are not shown, electrical current or voltage may be
passed to release segment 835 along modified snare line 132', which
is coupled to current generator 836. Current generator 836 may
include a safety latch or cover 837 to protect against inadvertent
application of electrical current to release segment 835. Release
segment 835 includes first and second terminals 838, 839, across
which electrical current or voltage may be applied by disabling
safety latch or cover 837 and actuating current generator 836 such
as illustrated in FIG. 8C. The resulting breakage of wire/suture
833' detaches filter 120 from sheath 110 and allows filter 120 to
be retracted into lumen 113 of sheath 110 by retracting modified
snare line 132' in a similar manner as described above.
[0057] Materials suitable for use in wire/suture 833, e.g.,
materials that may be formed into wires or sutures and that break
when electrical current or voltage is applied thereto, are known in
the relevant art.
[0058] FIGS. 9A-9D illustrate another alternative mechanism that
may be used to release filter 120 from sheath 110 prior to
retraction into lumen 113. In this embodiment, a combined
release/retraction mechanism permits both functions to be performed
using only a single mechanism, thus simplifying the design of
sheath 110 by obviating the need to provide multiple separate
grooves or lumens to control release and retraction of filter 120.
Referring to FIG. 9A, second ring 124 of filter 120 is coupled via
sutures, adhesive, or the like to fabric ring 901, which is a ring
of flexible, biocompatible fabric having a length sufficiently
short to avoid folding-in of the fabric during device or introducer
retraction. Wire/suture 933 is stitched or woven through fabric
ring 901, and the first and second ends 941, 942 of wire/suture 933
are looped around pull pin 935. Pull pin 935 is disposed in pouch
936 attached to fabric ring 901. The combination of elements 901,
933, 935, and 936 secures filter 120 to the distal end of sheath
110.
[0059] As illustrated in FIG. 9B, modified snare line 132'' passes
through loop 937 of pin 935, and is attached to segment 938 which
has a larger outer diameter than the inner diameter of loop 937.
Modified snare line 132'' also includes slack portion 939 that
facilitates detachment of filter 120 from sheath 110 before the
filter is retracted into lumen 113 of sheath 110. Specifically, as
illustrated in FIG. 9C, initial retraction of modified snare line
132'' pulls segment 938 in the proximal direction, causing segment
938 to engage loop 937 of pin 935 while slack portion 939 is drawn
taut. Such motion pulls pin 935 proximally out of pouch 936, which
frees the first and second ends 941, 942 of wire/suture 933 and
detaches filter 120 from sheath 110. Further retraction of modified
snare line 132'' draws filter 120 into lumen 113 of sheath 110,
such as described above and as illustrated in FIG. 9D.
[0060] While various illustrative embodiments of the invention are
described above, it will be apparent to one skilled in the art that
various changes and modifications may be made therein without
departing from the invention. For example, although the embodiments
above have been described primarily with respect to configurations
suitable for use in the aortic arch, it should be appreciated that
the apparatus and methods suitably may be modified for percutaneous
use in other blood vessels and for other applications including but
not limited to: treatment of atherosclerotic arterial disease,
aneurysmal disease and venous thrombosis. The appended claims are
intended to cover all such changes and modifications that fall
within the true spirit and scope of the invention.
* * * * *