U.S. patent application number 11/679750 was filed with the patent office on 2008-08-28 for method and apparatus for replacing a prosthetic valve.
Invention is credited to Stanton J. Rowe.
Application Number | 20080208327 11/679750 |
Document ID | / |
Family ID | 39493393 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080208327 |
Kind Code |
A1 |
Rowe; Stanton J. |
August 28, 2008 |
METHOD AND APPARATUS FOR REPLACING A PROSTHETIC VALVE
Abstract
In one aspect, the present disclosure concerns a percutaneously
delivered adapter stent that is deployed within a previously
implanted prosthetic valve and serves as an anchor or platform for
implanting a percutaneously delivered replacement valve within the
previously implanted valve. The adapter stent can be delivered to
the implantation site via the patient's vasculature and positioned
within the previously implanted valve. The stent can then be
deployed to cause the stent to expand and become anchored to the
inner surface of the previously implanted valve. Subsequently, the
replacement valve can be positioned within the adapter stent and
deployed to cause the replacement valve to expand and become
anchored to the adapter stent. The adapter stent and the
replacement valve can be mounted on the same catheter for delivery
to the implantation site.
Inventors: |
Rowe; Stanton J.; (Newport
Beach, CA) |
Correspondence
Address: |
EDWARDS LIFESCIENCES CORPORATION
LEGAL DEPARTMENT, ONE EDWARDS WAY
IRVINE
CA
92614
US
|
Family ID: |
39493393 |
Appl. No.: |
11/679750 |
Filed: |
February 27, 2007 |
Current U.S.
Class: |
623/2.11 ;
604/509; 623/1.11 |
Current CPC
Class: |
A61F 2250/0039 20130101;
A61F 2230/0078 20130101; A61F 2/2436 20130101; A61F 2/2433
20130101; A61F 2250/006 20130101; A61F 2220/0075 20130101; A61F
2250/0069 20130101; A61F 2220/0008 20130101; A61F 2/243 20130101;
A61F 2/2418 20130101; A61F 2/2427 20130101; A61F 2230/0054
20130101; A61F 2220/0016 20130101 |
Class at
Publication: |
623/2.11 ;
604/509; 623/1.11 |
International
Class: |
A61F 2/24 20060101
A61F002/24; A61F 2/06 20060101 A61F002/06; A61M 35/00 20060101
A61M035/00 |
Claims
1. A method of percutaneously implanting a replacement prosthetic
valve at a site occupied by a previously implanted prosthetic
valve, the method comprising: positioning a stent within the
previously implanted valve; deploying the stent to cause the stent
to become anchored to the previously implanted valve; positioning
the replacement valve within the deployed stent; and deploying the
replacement valve to cause the replacement valve to become anchored
to the stent.
2. The method of claim 1 wherein the stent and the replacement
valve are mounted on a common delivery catheter, which is used to
position stent and the replacement valve at their respective
deployment positions.
3. The method of claim 2 wherein: the stent is mounted on a first
balloon of the catheter and the replacement valve is mounted on a
second balloon of the catheter; deploying the stent comprises
inflating the first balloon to cause the stent to expand and engage
the previously implanted valve; and deploying the replacement valve
comprises inflating the second balloon to cause the replacement
valve to engage the stent.
4. The method of claim 2, wherein: the stent is self-expandable and
is retained in a radially compressed state on the catheter by a
sheath; and deploying the stent comprises withdrawing the sheath
from the stent to allow the stent to expand and engage the
previously implanted valve.
5. The method of claim 4, wherein: the replacement valve is
self-expandable and is retained in a radially compressed state on
the catheter by the sheath; and deploying the replacement valve
comprises withdrawing the sheath from the replacement valve to
allow it to expand and engage the stent.
6. The method of claim 1, wherein: the stent has a length that is
greater than the length of the previously implanted valve and
enlarged opposite end portions that are greater in diameter than an
intermediate portion of the stent when the stent is deployed; and
when the stent is deployed, the enlarged opposite end portions of
the stent are positioned outside of the previously implanted valve
to assist in retaining the deployed stent in place.
7. The method of claim 1, the stent comprises an annular sealing
member that creates a seal between the previously implanted valve
and the replacement valve once deployed.
8. The method of claim 7, wherein the sealing member comprises an
elastomer.
9. The method of claim 8, wherein the sealing member comprises
sponge rubber.
10. The method of claim 1, wherein the previously implanted valve
is located in the aortic annulus of a patient and the stent and the
replacement valve are delivered to the deployment site via the
aorta.
11. The method of claim 1, wherein the replacement valve comprises
a frame and a valve member secured to the stent.
12. A method of percutaneously implanting a replacement prosthetic
valve in a patient at a site occupied by a previously implanted
prosthetic valve, the method comprising: advancing a catheter
carrying a stent through the patient's vasculature to position the
stent within the previously implanted valve, the catheter also
carrying the replacement valve; deploying the stent to cause the
stent to become anchored to the previously implanted valve;
re-positioning the catheter to position the replacement valve
within the deployed stent; and deploying the replacement valve to
cause the replacement valve to become anchored to the stent.
13. The method of claim 12 wherein: the stent is mounted on a first
balloon of the catheter and the replacement valve is mounted on a
second balloon of the catheter; deploying the stent comprises
inflating the first balloon to cause the stent to expand and engage
the previously implanted valve; and deploying the replacement valve
comprises inflating the second balloon to cause the replacement
valve to engage the stent.
14. The method of claim 12, wherein when the stent is deployed,
opposite end portions of the stent extend outside opposite ends of
the previously implanted valve and flare radially outwardly with
respect to the opposite ends of the previously implanted valve.
15. An assembly for percutaneous replacement of a previously
implanted prosthetic valve without removal of the previously
implanted valve, the assembly comprising: an adapter stent
comprising a frame and an annular sealing member, the adapter stent
being adapted to be deployed within the previously implanted valve;
and a percutaneous, replacement prosthetic valve comprising a frame
and a flexible valve member, the valve being adapted to be deployed
within the deployed stent such that the sealing member provides a
seal between the previously implanted valve and the replacement
valve.
16. The assembly of claim 15 wherein the sealing member comprises
an elastomer.
17. The assembly of claim 15, wherein the sealing member extends
substantially the entire length of the frame of the adapter
stent.
18. The assembly of claim 15, wherein the sealing member is mounted
on the outside of the frame of the adapter stent.
19. The assembly of claim 15, wherein the sealing member is mounted
on the inside of the frame of the adapter stent.
20. The assembly of claim 15, wherein the frame of the adapter
stent has an inlet end portion, an outlet end portion, and an
intermediate portion extending between the end portions, the end
portions being greater in diameter than the intermediate
portion.
21. The assembly of claim 15, wherein the frame of the adapter
stent has a length of at least about 10 mm.
22. The assembly of claim 15, wherein the frames of the replacement
valve and the adapter stent are self-expandable.
23. The assembly of claim 15, wherein the replacement valve is a
prosthetic heart valve.
24. An assembly for percutaneous replacement of a previously
implanted prosthetic valve without removal of the previously
implanted valve, comprising; a replacement prosthetic valve having
a frame and a flexible valve member, the replacement prosthetic
valve being radially expandable and collapsible; and means for
anchoring and sealing the replacement valve to the previously
implanted valve, said means being separately deployable within the
previously implanted valve prior to deploying the replacement valve
within said means.
25. The assembly of claim 24, wherein said means comprises an
expandable frame and an annular sealing member secured to the
frame.
Description
FIELD
[0001] The present invention relates to embodiments of a method and
apparatus for replacing a previously implanted prosthetic valve,
such as a surgically implanted prosthetic heart valve, without
removing the previously implanted valve from the body.
BACKGROUND
[0002] Prosthetic valves, such as prosthetic heart valves, are
implanted in the body to replace a failing or diseased natural
valve. Should the prosthetic valve begin to fail, it also may need
to be replaced with another prosthetic valve. Surgically implanted,
prosthetic heart valves, such as a prosthetic aortic valve,
typically are replaced about every 15 years. The current method for
replacing a surgically implanted, prosthetic heart valve involves
open heart surgery wherein the patient's chest is opened and the
existing prosthetic valve is removed and replaced with a new
prosthetic valve. As can be appreciated, this is a traumatic and
high risk procedure accompanied by substantial morbidity and
mortality, and in some cases, cannot even be attempted due to the
advanced age and/or medical condition of the patient.
[0003] Therefore, it would be preferable to replace a prosthetic
heart valve with a percutaneously implanted valve that is delivered
to the implantation site via the patient's vasculature and deployed
within the previously implanted valve. However, because existing
prosthetic heart valves can vary widely in size and shape, there
are substantial difficulties associated with the development and
validation of a percutaneously delivered replacement valve that is
compatible with different types of existing prosthetic heart
valves. More particularly, difficulties arise because a replacement
valve that does not conform to the geometry of the previously
implanted valve may not be able to adequately anchor to the
previously implanted valve and/or form an effective seal with the
previously implanted valve.
SUMMARY
[0004] In one aspect, the present disclosure concerns a
percutaneously delivered adapter stent that is deployed within a
previously implanted prosthetic valve and serves as an anchor or
platform for implanting a percutaneously delivered replacement
valve within the previously implanted valve. The replacement valve
can be any known percutaneous valve. The adapter stent can be
adapted to provide a suitable mounting platform for implanting a
percutaneous replacement valve in a wide range of existing surgical
valves, which typically vary widely in size and shape from patient
to patient. In one advantageous feature, the adapter stent
increases the frictional forces between the percutaneous
replacement valve and the failing surgical valve, thereby providing
a more predictable orientation and securement of the percutaneous
replacement valve. Hence, this technique is particularly suited for
replacing a surgically implanted prosthetic heart valve, but also
could be used for replacing a percutaneously implanted prosthetic
valve.
[0005] The adapter stent can be delivered to the implantation site
via the patient's vasculature and positioned within the previously
implanted valve. The stent can then be deployed to cause the stent
to expand and become anchored to the inner surface of the
previously implanted valve. Subsequently, the replacement valve can
be positioned within the adapter stent and deployed to cause the
replacement valve to expand and become anchored to the adapter
stent.
[0006] In particular embodiments, the adapter stent and the
replacement valve can be mounted on the same delivery catheter for
delivery to the implantation site. In one implementation, for
example, the adapter stent and the replacement valve can be crimped
around respective first and second balloons of a double-balloon
catheter. In this approach, the adapter stent is positioned in the
previously implanted valve and expanded into contact with the
previously implanted valve by inflating the first balloon. The
catheter is then repositioned to place the replacement valve in the
deployed adapter stent, after which the valve is expanded into
contact with the adapter stent by inflating the second balloon. In
another implementation, the adapter stent and the replacement valve
are self-expandable. The self-expandable adapter stent and valve
can be mounted on a common delivery catheter adapted to retain the
stent and the valve in compressed positions while they are advanced
through the patient's vasculature. Using the catheter, the adapter
stent and the valve can be successively positioned and deployed
within the previously implanted valve.
[0007] The adapter stent in exemplary embodiments can comprise an
expandable frame that mounts a flexible annular sealing member. The
sealing member provides a seal between the previously implanted
valve and the replacement valve to prevent or at least minimize
blood flow between the original and replacement valves.
[0008] The adapter stent may be configured to have a length that is
greater than the length of the previously implanted valve that
needs to be replaced. This allows the stent to extend over the
entire inner surface of the previously implanted valve to provide
sufficient surface area for anchoring the replacement valve and to
ensure that the previously implanted valve does not interfere with
the positioning and deployment of the replacement valve. In certain
embodiments, the adapter stent, when expanded, has enlarged end
portions that flare or extend radially outwardly past the adjacent
ends of the previously implanted valve to assist in securing the
adapter stent in place.
[0009] In one representative embodiment, a method is provided for
percutaneously implanting a replacement prosthetic valve at a site
occupied by a previously implanted prosthetic valve. The method
includes positioning an adapter stent within the previously
implanted valve, deploying the adapter stent to cause the adapter
stent to become anchored to the previously implanted valve,
positioning the replacement valve within the deployed adapter
stent, and deploying the replacement valve to cause the replacement
valve to become anchored to the adapter stent.
[0010] In another representative embodiment, a method of
percutaneously implanting a replacement prosthetic valve in a
patient at a site occupied by a previously implanted prosthetic
valve includes advancing a catheter carrying an adapter stent
through the patient's vasculature to position the adapter stent
within the previously implanted valve. The catheter also carries
the replacement valve. The method further includes deploying the
adapter stent to cause the adapter stent to become anchored to the
previously implanted valve, repositioning the catheter to position
the replacement valve within the deployed adapter stent, and
deploying the replacement valve to cause the replacement valve to
become anchored to the adapter stent.
[0011] In another representative embodiment, an assembly is
provided for percutaneous replacement of a previously implanted
prosthetic valve without removal of the previously implanted valve.
The assembly comprises an adapter stent comprising a frame and an
annular sealing member. The adapter stent is adapted to be deployed
within the previously implanted valve. The assembly also includes a
percutaneous, replacement prosthetic valve comprising a frame and a
flexible valve member. The valve is adapted to be deployed within
the deployed adapter stent such that the sealing member provides a
seal between the previously implanted valve and the replacement
valve.
[0012] In yet another representative embodiment, an assembly for
percutaneous replacement of a previously implanted prosthetic valve
comprises a percutaneous, replacement prosthetic valve comprising a
frame and a flexible valve member. The assembly also includes means
for anchoring and sealing the replacement valve to the previously
implanted valve, said means being separately deployable within the
previously implanted valve prior to deploying the replacement valve
within said means.
[0013] The foregoing and other features and advantages of the
invention will become more apparent from the following detailed
description, which proceeds with reference to the accompanying
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a side elevation view of one embodiment of an
assembly comprising a percutaneous prosthetic valve and an adapter
stent for anchoring the prosthetic valve within a previously
implanted prosthetic valve.
[0015] FIG. 2 is a perspective view of the prosthetic valve shown
in FIG. 1.
[0016] FIG. 3 is a schematic side view of an embodiment of a
double-balloon catheter showing the prosthetic valve and the
adapter stent of FIG. 1 crimped around respective balloons on the
catheter for percutaneous delivery to an implantation site.
[0017] FIGS. 4A-4G illustrate the successive steps of one specific
embodiment of an implantation procedure employing the
double-balloon catheter shown in FIG. 2 for implanting the adapter
stent and the prosthetic valve inside a failing surgically
implanted, prosthetic valve previously implanted in the aortic
orifice of a patient.
[0018] FIG. 5 is a schematic side view of one embodiment of
delivery catheter that can be used to implant a self-expanding
adapter stent and replacement valve inside a previously implanted
valve.
[0019] FIG. 6 is a side elevation view of another embodiment of an
adapter stent that can be used to anchor a replacement valve within
a previously implanted prosthetic valve.
[0020] FIG. 7 illustrates another embodiment of an implantable
assembly for replacing a previously implanted prosthetic valve.
[0021] FIG. 8 illustrates the assembly of FIG. 7 deployed within a
previously implanted surgical valve.
DETAILED DESCRIPTION
[0022] As used herein, the singular forms "a," "an," and "the"
refer to one or more than one, unless the context clearly dictates
otherwise.
[0023] As used herein, the term "includes" means "comprises." For
example, a device that includes or comprises A and B contains A and
B but may optionally contain C or other components other than A and
B. A device that includes or comprises A or B may contain A or B or
A and B, and optionally one or more other components such as C.
[0024] In one aspect, the present disclosure concerns a
percutaneously delivered adapter stent that is deployed within a
previously implanted prosthetic valve and serves as an anchor or
platform for implanting a percutaneously delivered replacement
valve within the previously implanted valve. As used herein, the
term "stent" refers generally to any luminal structure. The
replacement valve can be any known percutaneous valve. The adapter
stent can be advanced through the patient's vasculature and
positioned within the previously implanted valve. The adapter stent
can then be deployed to cause the adapter stent to expand and
become anchored to the inner surface of the previously implanted
valve. The replacement valve can then be positioned within the
adapter stent and deployed to cause the replacement valve to expand
and become anchored to the adapter stent. In one respect, the
adapter stent is configured to increase the frictional forces
between the replacement valve and the failing previously implanted
valve, thereby providing a more predictable orientation and
securement of the replacement valve. In the following description,
the adapter stent and the replacement valve are shown and described
in connection with replacing a previously implanted aortic valve.
However, the embodiments described herein can also be used to
replace prosthetic valves implanted at other locations in the heart
or in other body channels having native valves, such as veins or
other organs.
[0025] FIG. 1 shows an assembly 10 comprising a percutaneous
prosthetic heart valve 12 and an adapter stent 30, according to one
embodiment. The adapter stent 30 can be deployed within a failing,
previously implanted valve, such as the prosthetic aortic valve 60
shown in FIG. 4A. Once the adapter stent 30 is deployed within the
previously implanted valve, the new valve 12 can be deployed within
the adapter stent 30 to replace the previously implanted valve 60.
The previously implanted valve 60 shown in the figures is a
surgical valve (i.e., a valve implanted via open heart surgery),
although the adapter stent 30 and the replacement valve 12 can also
be deployed within a previously implanted percutaneous valve.
[0026] The valve 12 and the adapter stent 30 are each crimpable or
compressible to a reduced diameter for percutaneous delivery to the
implantation site, such as using a delivery catheter. When expanded
to their functional size (FIG. 1), the outer diameter of the valve
12 desirably is approximately equal to the inner diameter of the
adapter stent and the outer surface of the valve 12 generally
conforms to an inner surface portion of the adapter stent 30 to
promote attachment of the valve 12 to the adapter stent 30. Methods
for implanting the adapter stent 30 and the valve 12 are described
in greater detail below.
[0027] As shown in FIGS. 1 and 2, the valve 12 in the illustrated
embodiment includes an annular frame 14 that mounts a flexible
valve member 16. The frame 14 in the illustrated embodiment
comprises a plurality of angularly-spaced axial struts, or support
members, 18 that extend axially (longitudinally) along the frame
and a plurality of support posts, or beams, 20 (one of which is
shown in FIGS. 1 and 2) spaced in the illustrated example at
120-degree intervals from each other around the frame 14. The
support posts 20 can be formed with apertures 22 to facilitate
attachment of the valve member 16 to the posts 20, such as, for
example, by suturing the valve member 16 to the posts. The frame 14
can also include a plurality of axially-spaced, circumferential
bands, or struts, 24 attached to the axial struts 18 and the
support posts 20. The struts 24 are formed with multiple bends that
allow the frame 14 to be crimped to a smaller diameter for delivery
to an implantation site and expanded to its functional size for
anchoring the valve assembly to the adapter stent 30 at the
implantation site. For example, each of the struts 24 in the
illustrated configuration includes a plurality of linear strut
members 26a, 26b arranged in a zig-zag or saw-tooth configuration
defining bends between adjacent strut members.
[0028] In alternative embodiments, the frame can have other
configurations. For example, one or more of the circumferential
bands 24 can have a curved or serpentine shape rather than a
zig-zag shape. Further, the frame 14 can include various attachment
elements (not shown), such as barbs, staples, flanges, and the like
for enhancing the ability of the frame to anchor to the adapter
stent 30.
[0029] The frame 14 can be made from any of various suitable
ductile and/or elastic materials and is typically made of a metal,
such as stainless steel, titanium, or other biocompatible metals.
The frame 14 or components thereof can also be made from a shape
memory alloy such as nickel titanium (NiTi) shape memory alloys, as
marketed, for example, under the trade name Nitinol. The
shape-memory components allow the valve 12 to be self-expandable;
that is, the valve 12, when restrained in a radially compressed
state by an outer restraint (e.g., a sheath covering the valve),
automatically expands to its functional size when the outer
restraint is removed.
[0030] The valve member 16 can have a leafed-valve configuration,
such as the tricuspid valve configuration shown in the illustrated
embodiment. The valve member 16 can be formed from three pieces of
pliant material connected to each other at seams aligned with posts
20 to form collapsible leaflets 28 (FIG. 2). The valve member 16
can be made from biological matter, such as natural tissue,
pericardial tissue (such as bovine, porcine or equine pericardium),
a harvested natural valve or other biological tissue.
Alternatively, the valve member 16 can be made from biocompatible
polymers or similar materials.
[0031] Various other prosthetic valve configurations also can be
used. Examples of other valves that can be utilized are disclosed
in U.S. Pat. No. 6,730,118, U.S. Pat. No. 6,767,362, and U.S. Pat.
No. 6,908,481, which are incorporated herein by reference.
[0032] The adapter stent 30 in exemplary embodiments includes an
expandable frame 32 that mounts a flexible annular sealing member
34. The frame 32 is shown in FIG. 1 in its expanded, functional
size, and is configured to be crimpable to a reduced diameter for
percutaneous delivery, such as on a delivery catheter. The frame 32
can be made from any of various suitable ductile and/or elastic
materials and is typically made of a metal, such as stainless
steel, titanium, or other biocompatible metals. The frame 14 or
components thereof can also be made from a shape memory material,
which allows the stent 30 to be self-expandable.
[0033] The frame 32 is the illustrated embodiment comprises a
plurality of longitudinally extending, zig-zag struts 36 joined to
each other at junctures 38. The frame 32 has a length L measured
between the opposite ends thereof that desirably is greater than
the length of the previously implanted valve that needs to be
replaced. In this manner, the frame 32, when deployed within the
previously implanted valve, can extend over the entire inner
surface area of the previously implanted valve to provide
sufficient surface area for anchoring the replacement valve 12 and
to ensure that the previously implanted valve does not interfere
with the positioning and deployment of the replacement valve 12. In
particular embodiments, for example, the length L of the frame is
about 10 mm to about 40 mm, with about 30 mm being a specific
example,
[0034] As shown, the frame 32 in exemplary embodiments has a
generally cylindrical intermediate portion 44 extending between the
opposite end portions 40, 42, which are enlarged or flared relative
to the intermediate portion 44 when the frame is expanded. Each end
portion 40, 42 desirably expands to a diameter that is greater than
the diameter of the previously implanted valve. Hence, when the
adapter stent 30 is deployed within the previously implanted valve,
the end portions 40, 42 can extend radially outwardly past the
adjacent ends of the previously implanted valve to assist in
securing the adapter stent in place.
[0035] In alternative embodiments, the frame 32 can have various
other shapes or configurations. For example, the frame 32 can be
generally cylindrical or tubular along its entire length without
enlarged end portions. The frame 32 optionally can be provided with
various attachment elements (not shown), such as barbs, staples,
flanges, and the like for enhancing the ability of the frame to
anchor to the previously implanted valve 60 (FIG. 4A). If desired,
the frame 32 may be provided with attachment elements along the
inner surface for enhancing the ability of the frame 32 to securely
engage the frame 14 of the percutaneously delivered replacement
valve 12.
[0036] The sealing member 34 provides a seal between the previously
implanted valve 60 and the replacement valve 12 to prevent or at
least minimize blood flow between the valves. As shown in FIG. 1,
the sealing member 34 desirably extends nearly the entire length of
the frame 32 to maximize the surface area that can contact the
previously implanted valve 60 and the replacement valve 12. In
other embodiments, however, the sealing member can extend along
only a portion of the frame 32, such as the intermediate portion
44. With reference to the embodiment shown in FIG. 1, the sealing
member 34 is secured to the inner surface of the frame 32.
Alternatively, the sealing member can be secured to the outer
surface of the frame 32 as shown in FIG. 6 to prevent the leakage
of blood. In another implementation, a sealing member 34 can be
secured to both the inner and outer surfaces of the frame 32.
[0037] In particular embodiments, the sealing member 34 is made of
a natural or synthetic biocompatible elastomeric material, such as
foam rubber, thermoplastic elastomers (e.g., polyurethanes) or
other polymeric elastomers, such as a polymeric sponge. The sealing
member 34 can be secured to or formed on the frame using any
suitable techniques or mechanisms, such as by suturing the sealing
member to the frame or co-molding the sealing member to the frame.
The sealing member 34 also can be formed on the frame using
conventional coating techniques, such as spray coating, dip
coating, or roll coating.
[0038] The valve 12 and the adapter stent 30 can be implanted using
a double-balloon catheter. FIG. 3, for example, shows the distal
end portion of an exemplary embodiment of a double-balloon
catheter, indicated at 70. The catheter 70 includes a shaft 72, on
which there are mounted first and second, spaced-apart balloons 74,
76, respectively, between a respective pair of rings 80, 82. The
adapter stent 30 and the replacement valve 12 are crimped around
the first balloon 74 and the second balloon 76, respectively. The
shaft 72 contains two lumens (not shown), each of which is fluidly
connected to a respective balloon 74, 76 for successive and
separate inflation of each balloon. The shaft 72 also contains
another lumen to accept a guide wire 78 so that the catheter can be
advanced over the guide wire 78 for guiding the catheter through
the patient's vasculature.
[0039] The catheter 70 can be introduced percutaneously into the
patient's vasculature (e.g., into a peripheral artery such as the
femoral artery) and advanced to the implantation site. For example,
for replacing a prosthetic aortic valve, the catheter in certain
embodiments has a length of at least about 80 cm, usually about
90-100 cm, to allow transluminal positioning of the shaft from the
femoral and iliac arteries to the ascending aorta. Alternatively,
the shaft may have a shorter length, e.g. about 20-60 cm, for
introduction through the iliac artery, through the brachial artery,
through the carotid or subclavian arteries, or through a
penetration in the aorta itself. In the femoral approach, the
catheter desirably is long enough and flexible enough to traverse
the path through the femoral artery, iliac artery, descending aorta
and aortic arch. At the same time, the catheter desirably has
sufficient pushability to be advanced to the ascending aorta by
pushing on the proximal end, and has sufficient axial, bending, and
torsional stiffness to allow the physician to control the position
of the distal end, even when the catheter is in a tortuous vascular
structure. Alternatively, the catheter may be passed through a port
between ribs in the patient's thorax above the heart and through an
incision in the heart wall (e.g., through the apex of the left
ventricle) or through an incision in the aortic arch, in a
so-called minimally-invasive procedure.
[0040] A procedure for implanting the valve 12 and the adapter
stent 30 using the catheter 70, according one embodiment, is
illustrated in FIGS. 4A-4G. FIG. 4A illustrates the previously
implanted valve 60 implanted in the aortic annulus between the left
ventricle chamber 86 and the ascending aorta 88. As noted above,
the illustrated valve 60 is a surgical valve, although the adapter
stent 30 and the replacement valve 12 can also be implanted within
an existing percutaneous valve. The catheter 70 can be introduced
percutaneously into the patient's vasculature and advanced to the
implantation site using known techniques. For example, a blood
vessel (e.g., the femoral artery) typically is dilated using a
conventional dilator to allow an introducer sheath to be inserted
into the blood vessel. The guide wire 78 can then be inserted into
the blood vessel via the introducer sheath and advanced to the
implantation site. Subsequently, the catheter 70 can be advanced
over the guide wire 78 to position the adapter stent 30 in the
previously implanted valve 60. More precisely, the adapter stent 30
desirably is positioned such that the end portions 40, 42 are
located outside the adjacent ends of the previously implanted valve
60, as shown in FIG. 4B.
[0041] As depicted in FIG. 4C, the balloon 74 is then inflated to
deploy the adapter stent 30, which expands to its functional size
and engages the inner surface of the previously implanted valve 60.
As shown, in its expanded stated, the end portion 40, 42 flare
radially outwardly past the adjacent ends of the previously
implanted valve to assist in retaining the adapter stent 30 in
place against the valve 60. In addition, the adapter stent 30, in
the illustrated example, also extends over the entire inner surface
area of the existing valve 60 and causes the flexible leaflets 62
of the valve to expand radially outwardly, thereby providing a
surface area suitable for mounting the replacement valve 12.
[0042] Thereafter, the balloon 74 is deflated (FIG. 4D) and the
catheter 70 is retracted slightly to position the replacement valve
12 within the deployed adapter stent 30 (FIG. 4E). The second
balloon 76 is then inflated to deploy the replacement valve 12,
which expands to its functional size and engages the inner surface
of the adapter stent 30 (FIG. 4F). Once the replacement valve 12 is
deployed, the balloon 76 can be deflated and the catheter 70 can be
removed from the body (FIG. 4G).
[0043] The adapter stent 30, as well as the valve 12, can be
positioned at the implantation site with the assistance of
fluoroscopy and radiopaque markers, ultrasonic imaging, and the
like. For example, rings 80, 82 on the catheter shaft 72 can be
made of any of various suitable metals that are visible during
fluoroscopy for use in positioning the adapter stent and/or the
valve. Alternatively, radiopaque markers can be provided on
portions of the adapter stent 30 and/or the valve 12.
[0044] In an alternative approach, the replacement valve 12 can be
mounted on the first balloon 74 and the adapter stent 30 can be
mounted on the second balloon 76. In this approach, the adapter
stent 30 is first deployed within the previously implanted valve 60
while the first balloon 74 and the replacement valve 12 are
positioned in the aorta 88. After the adapter stent 30 is deployed,
the catheter 70 is advanced further into the left ventricle 86 to
position the first balloon 74 and the replacement valve 12 within
the deployed adapter stent 30. The replacement valve 12 can then be
deployed by inflating the first balloon 74.
[0045] As noted above, the frame 32 of the adapter stent 30 and the
frame 14 of the replacement valve 12, or portions thereof, can be
made of a shape-memory material, which allows the adapter stent 30
and the valve 12 to be self-expandable. FIG. 5 is a schematic view
of the distal end portion of a delivery catheter, indicated at 90,
which can be used to implant a self-expanding replacement valve and
adapter stent in the previously implanted valve 60. The catheter 90
includes a shaft 92 and an outer sheath 94, which is moveable
longitudinally relative to the shaft 92. The shaft 92 can include a
lumen for receiving a guide wire 78. The valve 12 and the adapter
stent 30 are mounted to the shaft 92 in their compressed states.
The outer sheath 94 extends over the valve 12 and the adapter stent
30 to retain the valve and adapter stent in their compressed states
until each is positioned for deployment at the implantation
site.
[0046] The catheter 90 can be introduced into the body and advanced
through the patient's vasculature in the same manner as the balloon
catheter 70. The adapter stent 30 is first positioned in the
previously implanted valve 60 and the outer sheath is retracted to
expose the adapter stent 30, which permits the adapter stent to
expand into contact with the previously implanted valve. The
catheter 90 is then advanced slightly to position the valve 12 in
the deployed adapter stent 30. The outer sheath 94 can then be
retracted to expose the valve 12, which permits the valve to expand
into contact with the adapter stent.
[0047] Although less desirable, the adapter stent 30 and the
replacement valve 12 can be delivered and implanted at the site of
the previously implanted valve using separate catheters. For
example, the adapter stent 30 and the valve 12 can be mounted on
separate balloon catheters. In this approach, the adapter stent 30
is implanted using a first balloon catheter, which is then removed
from the body to allow a second balloon catheter carrying the
replacement valve to be inserted into the body.
[0048] As noted above, surgical valves, such as valve 60, typically
vary widely in size and shape from patient to patient.
Advantageously, the adapter stent 30 can be adapted to provide a
suitable mounting platform for implanting a percutaneous
replacement valve in a wide range of surgical valves varying in
size and shape.
[0049] FIG. 7 illustrates another exemplary embodiment of an
assembly 100 comprising a percutaneous prosthetic valve 12 and an
adapter stent 102. The adapter stent 102, like adapter stent 30,
includes a radially compressible and expandable frame 102 that
mounts a flexible annular sealing member 106. FIG. 8 illustrates
the adapter stent 102 and the prosthetic valve 12 deployed within a
previously implanted surgical valve 60. The adapter stent 102 has a
length L that is preferably greater than the length of the
previously implanted valve 60 but need not be longer than the new
valve 12. In certain embodiments, the adapter stent 102 has a
length L of about 10 mm and the new valve 12 has a length of about
20 mm.
[0050] In view of the many possible embodiments to which the
principles of the disclosed invention may be applied, it should be
recognized that the illustrated embodiments are only preferred
examples of the invention and should not be taken as limiting the
scope of the invention. Rather, the scope of the invention is
defined by the following claims. I therefore claim as my invention
all that comes within the scope and spirit of these claims.
* * * * *