U.S. patent application number 11/527769 was filed with the patent office on 2007-04-05 for prosthetic cardiac and venous valves.
Invention is credited to Timothy R. Ryan.
Application Number | 20070078510 11/527769 |
Document ID | / |
Family ID | 37563745 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070078510 |
Kind Code |
A1 |
Ryan; Timothy R. |
April 5, 2007 |
Prosthetic cardiac and venous valves
Abstract
A prosthetic heart or venous valve, the valve including a
central tissue structure with multiple tissue lobes extending from
a common central area, wherein each of the lobes includes a
longitudinal slot. The valve further includes a plurality of
leaflets, each extending from the central tissue structure and
positioned between two adjacent lobes, wherein each of the leaflets
has a free end spaced from the central tissue structure, and also
has a compressible and expandable stent frame with a plurality of
extending arms, wherein each of the extending arms of the stent
frame is positioned at least partially within one of the
longitudinal slots of the central tissue structure.
Inventors: |
Ryan; Timothy R.;
(Shorewood, MN) |
Correspondence
Address: |
KAGAN BINDER, PLLC
SUITE 200, MAPLE ISLAND BUILDING
221 MAIN STREET NORTH
STILLWATER
MN
55082
US
|
Family ID: |
37563745 |
Appl. No.: |
11/527769 |
Filed: |
September 26, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60720398 |
Sep 26, 2005 |
|
|
|
Current U.S.
Class: |
623/1.26 ;
623/2.18 |
Current CPC
Class: |
A61F 2/2418 20130101;
A61F 2220/0066 20130101; A61F 2220/0016 20130101; A61F 2220/005
20130101; A61F 2/2436 20130101; A61F 2/2475 20130101 |
Class at
Publication: |
623/001.26 ;
623/002.18 |
International
Class: |
A61F 2/06 20060101
A61F002/06 |
Claims
1. A prosthetic heart or venous valve, comprising: a central tissue
structure comprising multiple tissue lobes extending from a common
central area, wherein each of the lobes includes a longitudinal
slot; a plurality of leaflets, each of which extends from the
central tissue structure and is positioned between two adjacent
lobes, wherein each of the leaflets comprises a free end spaced
from the central tissue structure; and a flexible stent frame
comprising a plurality of extending arms, wherein each of the
extending arms of the stent frame is positioned at least partially
within one of the longitudinal slots of the central tissue
structure.
2. The valve of claim 1, wherein the central tissue structure
comprises a native valve segment that has been inverted to provide
the plurality of leaflets.
3. The valve of claim 2, wherein the multiple tissue lobes are
formed by folded portions of an aortic wall of the native valve
segment.
4. The valve of claim 3, wherein the native valve segment comprises
a porcine valve segment.
5. The valve of claim 1, wherein the plurality of extending arms
are connected to each other at a common point that is positioned at
an inflow end of the valve, wherein the stent frame comprises a
distal portion that extends beyond the central tissue structure at
an outflow end of the valve, and wherein the distal portion of the
stent frame further comprises an anchoring mechanism.
6. The valve of claim 5, wherein the anchoring mechanism comprises
at least one connector extending from each of the extending arms
that is engageable with a thickness of tissue.
7. The valve of claim 5, wherein the anchoring mechanism comprises
a compressible and expandable engagement structure extending from
the stent frame.
8. The valve of claim 7, wherein the engagement structure comprises
a self-expanding material.
9. The valve of claim 1, wherein the plurality of leaflets are
moveable from a first position in which their free ends are spaced
at a first distance from the central tissue structure to a second
position in which their free ends are spaced at a second distance
from the central tissue structure that is greater than the first
distance, wherein the first position of the leaflets defines a
plurality of channels between adjacent lobes of the central tissue
structure and provides an open position of the valve.
10. The valve of claim 9, wherein the second position of the
leaflets eliminates the plurality of channels between adjacent
lobes of the central tissue structure and provides a closed
position of the valve.
11. A prosthetic valve, comprising: a flexible tube having an
inflow end and a outflow end, wherein the inflow end of the tube is
folded against and attached to itself and the outflow end of the
tube is open; and a stent having multiple longitudinally extending
members located at least partially within the tube and extending to
the open outflow end of the tube, wherein portions of the tube that
are adjacent to the outflow end of the tube and between the
longitudinally extending members of the stent are moveable toward
and away from a central area of the valve to provide a plurality of
valve leaflets.
12. A prosthetic valve according to claim 11, wherein the stent
comprises a distal portion that extends beyond the outflow end of
the tube, and wherein the distal portion of the stent further
comprises an anchoring mechanism.
13. The valve of claim 12, wherein the anchoring mechanism
comprises at least one connector extending from each of the
extending members that is engageable with a thickness of
tissue.
14. The valve of claim 12, wherein the anchoring mechanism
comprises a compressible and expandable engagement structure
extending from the stent.
15. The valve of claim 14, wherein the engagement structure
comprises a self-expanding material.
16. The valve of claim 11, further comprising at least one spacer
positioned between portions of the tube that are adjacent the open
outflow end of the tube.
17. The valve of claim 16, wherein the at least one spacer extends
from and is attached to the inflow end of the tube and extends
generally along a central longitudinal axis of the tube.
18. The valve of claim 11, wherein the stent comprises three
longitudinally extending members and wherein the valve comprises
three leaflets defined by the three extending members and the open
outflow end of the tube.
19. The valve of claim 18, wherein the stent and leaflets are sized
to provide a central aperture that is open to the inside of the
tube at the outflow end of the tube when the valve is in its open
position and when the valve is in its closed position.
20. The valve of claim 11, wherein the stent comprises two
longitudinally extending members and the valve comprises two
leaflets.
Description
PRIORITY CLAIM
[0001] This application claims the benefit of U.S. Provisional
Patent Application having Ser. No. 60/720,398 filed on Sep. 26,
2005, entitled "Prosthetic Cardiac Valves", the entire disclosure
of which is incorporated herein by reference for all purposes.
TECHNICAL FIELD
[0002] The present invention relates to prosthetic heart and venous
valves used in the treatment of cardiac and venous valve disease.
More particularly, it relates to minimally invasive and
percutaneous replacement of cardiac and venous valves.
BACKGROUND
[0003] Recently, there has been a substantial level of interest in
minimally invasive and percutaneous replacement of cardiac valves.
In the specific context of pulmonary valve replacement, U.S. patent
application Publication Nos. 2003/0199971 A1 and 2003/0199963 A1,
(Tower et al.), which are incorporated herein by reference in their
entireties, describe a valved segment of bovine jugular vein
mounted within an expandable stent, for use as a replacement
pulmonary valve. The replacement valve is mounted on a balloon
catheter and delivered percutaneously via the vascular system to
the location of the failed pulmonary valve and expanded by the
balloon to compress the valve leaflets against the right
ventricular outflow tract, anchoring and sealing the replacement
valve. The valve is also useful to replace failed pulmonary valves
located in valved conduits.
[0004] U.S. Pat. No. 5,411,552 (Andersen et al.) discloses a
percutaneously deliverable valve for aortic valve replacement. Like
the Tower et al. valve, this valve system employs a stent external
to the valve to exert pressure against the vessel at the implant
site to provide a seal. This pressure of the stent against the
vessel also helps to keep the valve from becoming displaced once it
has been implanted. With these and other percutaneously delivered
valves, the stent or other expandable member is typically designed
to surround at least the valve orifice. This basic configuration
allows blood to flow through the center of the valve when the valve
is open, with the multiple valve leaflets sealing against
themselves to close the valve. Because the native aortic valve
annulus in which the replacement is to be implanted may be
calcified and have an irregular perimeter, this basic configuration
can be problematic, particularly in the context of replacement
aortic valves. For example, a valve annulus with an irregular
perimeter can make it difficult for an expanded stent to accurately
follow the contours of the native annulus, which can result in
peripheral fluid leakage. This problem is typically not present in
traditional surgically implanted valves, since their relatively
rigid stents are typically sealed to the valve annulus with a
sealing ring that is attached to the annulus by means of numerous
sutures.
[0005] Other procedures and devices that have been developed
include, for example, surgically implantable valves disclosed in
U.S. Pat. Nos. 4,339,831 (Johnson) and 5,449,384 (Johnson), both of
which are incorporated herein in their entireties. These valves
have a configuration that is essentially the opposite of the
natural configuration, such that the valve leaflets open inwardly
and close by expanding outwardly to contact the native aortic valve
annulus. These valves further include a framework comprising a
plurality of struts that are sutured to the patient's annulus or an
artificial annulus reconstruction ring and a flexible membrane
attached to the framework to allow the membrane segments or
leaflets to freely open inward to allow forward blood flow through
the valve. Although the struts are described as being flexible,
these valves are not contemplated to be implanted percutaneously
due to the need to physically suture these implantable valves to
the annulus of a patient. Another type of valve that was developed
is described in U.S. Pat. No. 3,671,979 (Moulopoulos). This
reference discloses a valve that can be inserted, withdrawn and
retained relative to its desired implanted position with the use of
a catheter. A membrane of the valve expands outward like an
umbrella to seal against the interior of the aorta, downstream of a
damaged aortic valve, and collapses and enfolds the catheter to
allow flow of blood when the valve is open. However, this valve is
not capable of being retained in this position and functioning as a
valve without the use of its catheter.
[0006] There is a continued desire to provide cardiac valves that
can be implanted in a minimally invasive and percutaneous manner,
while minimizing or eliminating paravalvular leakage.
SUMMARY
[0007] The present invention is particularly directed to
improvements in minimally invasive and percutaneously delivered
valves for use in pulmonary and aortic positions. However, the
invention may also be useful in other types of valves, including
other heart valves and peripheral venous valves. In particular, a
valve of the invention has leaflets that are configured to operate
in an essentially an opposite manner from a typical artificial
valve. Using this reverse or opposite configuration in a minimally
invasively or percutaneously delivered valve with a collapsible
stent can provide certain benefits. In particular, the outwardly
sealing valve leaflets may adapt themselves or conform more readily
to irregular configurations of the orifice in which the valve is
mounted, thereby overcoming or reducing the sealing problems
sometimes associated with expandable stents that are external to
the valve leaflets.
[0008] The present invention also includes embodiments of a variety
of outwardly sealing multi-leaflet valves, which are believed to be
especially useful in conjunction with a number of different
embodiments of collapsible stents.
[0009] In some embodiments of the invention, the valve leaflets are
produced by inverting a section of a naturally valved vessel, such
as a porcine aorta or a bovine jugular vein. In other embodiments,
the valve leaflets are produced by sealing one end of a flexible
tube and employing the unsealed end to define the leaflets. In yet
other embodiments, the valve is produced by stitching together
leaflets of flexible material such as pericardial tissue to provide
a generally cup shaped structure. With any of these described
embodiments, the valve leaflets are mounted to an expandable stent
which is to be anchored to the orifice in which the valve is
implanted. This valve implantation is positioned to be downstream
of or adjacent to the free edges of the leaflets.
[0010] In some embodiments of the invention, the expandable stent
may be configured with a flexible frame that is manufactured of a
material consistent with being collapsed to allow delivery through
a tubular percutaneous catheter or minimally invasive tubular
surgical port type device. In other embodiments, the stent may
include a self-expanding or balloon expandable circumferential
stent that is located downstream of the free edges of the valve
leaflets. In still other embodiments the stent may include
outwardly extending barbs that are preferably, but not necessarily,
located downstream of the free edges of the leaflets.
[0011] In one embodiment of the invention, a prosthetic heart or
venous valve is provided, the valve comprising a central tissue
structure comprising multiple tissue lobes extending from a common
central area, wherein each of the lobes includes a longitudinal
slot. The valve further comprises a plurality of leaflets extending
from the central tissue structure and positioned between two
adjacent lobes, wherein each of the leaflets comprises a free end
spaced from the central tissue structure, and also comprises a
compressible and expandable stent frame comprising a plurality of
extending arms, wherein each of the extending arms of the stent
frame is positioned at least partially within one of the
longitudinal slots of the central tissue structure. The central
tissue structure can comprise a native valve segment that has been
inverted to provide the plurality of leaflets, wherein the multiple
tissue lobes can be formed by folded portions of an aortic wall of
the native valve segment.
[0012] In another aspect of the invention, a prosthetic valve is
provided, which comprises a flexible tube having an inflow end and
a outflow end, wherein the inflow end of the tube is folded against
and attached to itself and the outflow end of the tube is
unattached to itself, and a stent having multiple longitudinally
extending members located at least partially within the tube and
extending to the open outflow end of the tube, wherein portions of
the tube that are adjacent the outflow end of the tube and between
the longitudinally extending members of the stent are moveable
toward and away from a central area of the valve to provide a
plurality of valve leaflets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will be further explained with
reference to the appended Figures, wherein like structure is
referred to by like numerals throughout the several views, and
wherein:
[0014] FIG. 1 is a top view of a natural aortic valve;
[0015] FIG. 2 is a top view of the natural aortic valve of FIG. 1
with the valve structure turned "inside-out" on itself such that
the leaflets are positioned on the outside of the valve in a
tri-lobed configuration;
[0016] FIG. 3 is a side view of the natural aortic valve turned
"inside-out" as in FIG. 2, with the aortic wall sutured to itself
at an inflow end of the valve;
[0017] FIG. 4 is a side view of the natural aortic valve turned
"inside-out" as in FIG. 2, with the aortic wall sutured to itself
at an inflow end of the valve, wherein the aortic wall is trimmed
to more closely match the configuration of typical valve
leaflets;
[0018] FIG. 5 is a side view of one embodiment of a stent for use
in conjunction with valves of the type illustrated in FIGS. 3 and
4;
[0019] FIG. 6 is a side view of the stent of FIG. 5 mounted inside
a valve of the type illustrated in FIG. 4 to provide one embodiment
of a completed replacement valve of the invention;
[0020] FIG. 7 is a side view of the replacement valve of FIG. 6, as
positioned within an aortic annulus, which is illustrated in
cross-section;
[0021] FIG. 8 is a side view of a delivery catheter or device
positioned within an aortic annulus, with the replacement valve of
FIG. 6 partially advanced from one end of the catheter or
device;
[0022] FIG. 9 is a side view of the delivery catheter or device
illustrated in FIG. 8, with the replacement valve of FIG. 6 being
further advanced from one end of the catheter into the aortic
annulus;
[0023] FIG. 10 is a side view of the replacement valve of FIG. 6 in
a desired position within an aortic annulus, which is also the
position it will generally be in after it has been completely
advanced from the end of the delivery device of FIGS. 8 and 9;
[0024] FIG. 11 is a side view of a delivery catheter within an
aortic annulus that includes a balloon catheter that is radially
expandable to anchor a replacement valve into the tissue of a
patient;
[0025] FIG. 12 is a side view of an alternative embodiment of a
replacement valve of the type illustrated in FIG. 6 as positioned
within an aortic annulus, which includes an alternative embodiment
for anchoring the valve;
[0026] FIG. 13 is a side view of another alternative embodiment of
a replacement valve of the type illustrated in FIG. 6 as positioned
within an aortic annulus, which includes another alternative
embodiment for anchoring the valve;
[0027] FIG. 14 is a top view of a replacement valve generally of
the type illustrated in FIG. 6, which further includes optional
tissue or fabric portions to prevent leakage adjacent the valve
commissures;
[0028] FIG. 15 is a side view of an alternative structure to
provide valve leaflets that are mounted to a stent to provide an
alternative embodiment of a completed replacement valve of the
invention;
[0029] FIG. 16 is a side view of the alternative valve leaflet
structure of FIG. 15, which uses an alternative stent
configuration;
[0030] FIG. 17 is a side view of a flexible tube of natural or
synthetic material as can be used for replacement valves of the
invention;
[0031] FIG. 18 is a perspective view of a replacement valve
fabricated from the tube of FIG. 17 and mounted to a stent, which
includes having its inflow end sutured to produce a tri-lobed
structure;
[0032] FIG. 19 is a top view of the replacement valve of FIG. 18,
as located within the aortic annulus;
[0033] FIG. 20 is a top view of an alternative structure of the
replacement valve of FIG. 18;
[0034] FIG. 21 is at top view of another alternative structure of
the replacement valve of FIG. 18;
[0035] FIG. 22 is an enlarged top view of a portion of the
replacement valve of FIG. 21;
[0036] FIG. 23 is a perspective view of a replacement valve
fabricated from the tube of the type illustrated in FIG. 17 and
mounted to a stent, which includes having its inflow end sutured to
create a bi-lobed structure;
[0037] FIG. 24 is an enlarged top view of a portion of the
replacement valve of FIG. 23;
[0038] FIG. 25 is a perspective view of an alternative embodiment
of the replacement valve of FIG. 23, which is folded onto itself to
provide for passage through a catheter;
[0039] FIG. 26 is a perspective view of an alternative stent
configuration for use with the leaflets configured in accordance
with the present invention;
[0040] FIG. 27 is a top view of another embodiment of a replacement
valve having a bi-lobed structure; and
[0041] FIG. 28 is a top view of another embodiment of a replacement
valve having a bi-lobed structure.
DETAILED DESCRIPTION
[0042] Referring now to the Figures, wherein the components are
labeled with like numerals throughout the several Figures, and
initially to FIG. 1, a natural aortic valve 3 is illustrated, which
generally comprises three leaflets 2 extending from an aortic wall
4. The leaflets 2 meet at their free edges 6 to seal the valve
orifice when the valve 3 is in its closed position. The free edges
6 can move away from each other and toward the aortic wall 4,
however, when the valve 3 is in its open configuration, thereby
creating an open passage for blood flow. Such a natural aortic
valve 3 may be a valved segment of a porcine valve, for example,
which can be particularly advantageous in certain aspects of the
invention due to the relatively thin aortic walls of these
valves.
[0043] FIG. 2 illustrates an top view of an aortic valve 16, which
is basically the valve 3 of FIG. 1 turned "inside-out" as compared
to its natural state. That is, the aortic wall 4 is folded or
rolled inwardly so that the side of the wall 4 that was previously
facing in an outward direction is on the inside of the valve 16.
The aortic wall 4 is further configured so that it defines a
tri-lobed configuration, with the leaflets 2 on the outside of the
valve 16 rather than the inside of the valve, as will be described
in further detail below. In this configuration, the free edges 6 of
leaflets 2 are located at the external periphery of the valve 16
such that the free edges 6 no longer will be in contact with each
other when the valve 16 is in its closed configuration, but instead
will be in contact with the vessel in which it is implanted (e.g.,
aorta). In fact, the leaflets 2 are facing in a generally opposite
direction from the direction they are facing in a valve in its
natural state.
[0044] In the embodiment of FIG. 2, the aortic wall 4 further
defines three internal longitudinally extending slots 8 in the area
where the wall 4 is folded onto or toward itself. That is, each of
the lobes of the tri-lobed configuration includes a slot 8
extending through it. Because the valve 16 opens inwardly, rather
than outwardly, relative to the structure in which it is positioned
(e.g., an aorta), the leaflets 2 will seal against the aorta or
other structure in which the valve is positioned when the valve 16
is in a closed state and will move toward the inner, tri-lobed
structure when the valve 16 is in an open state. Thus, paravalvular
leakage can be minimized or eliminated as compared to valves in
which the radial strength of a stent is an issue.
[0045] In order to allow the free edges 6 of leaflets 2 of FIG. 2
to better conform to the tissue annulus in which the valve 16 is
positioned, it is desirable for the leaflets 2 to have a certain
level of elasticity. This can be accomplished by fixing the valve
material with glutaraldehyde, for example, using conventional high,
low or zero pressure fixation techniques, although other fixing
techniques and materials can be used. In some embodiments, the
aortic wall 4 may be trimmed to reduce the thickness of the wall,
which will provide different properties for the valve (e.g.,
strength, flexibility, and the like). In addition to the porcine
valve material discussed above, such a valve structure can be
produced, for example, starting with a valved segment of bovine
jugular vein that is trimmed to make its walls thinner and thus
more adaptable to at least some of the valve configurations of the
invention.
[0046] FIG. 3 illustrates a side view of the valve 16 of FIG. 2,
with adjacent portions of an inflow end 12 of the folded aortic
wall 4 attached to each other by sutures 10 to seal the end of the
valve 16 and maintain the tri-lobed structure. Alternatively,
adhesive or other surgical fasteners can be used to secure the
inflow end 12 of the structure in such a configuration. In either
case, in order to pull the sections of the wall 4 closer to each
other along the slots 8, a vacuum can be pulled on the valve 16
prior to using the sutures or other material to seal the end of the
valve 16. FIG. 4 illustrates an alternative embodiment of the
aortic valve of FIG. 3, with the inflow end 12 of the aortic wall 4
being trimmed into a curved shape to more closely match the
configuration of the bases of the valve leaflets 2 and to eliminate
excess valve material extending beyond the leaflets 2.
[0047] Referring now to FIG. 5, one embodiment of a stent 18 is
shown, which can be used in conjunction with valves of the type
illustrated in FIGS. 3 and 4. The stent 18 includes three
longitudinally extending curved arms 20 that extend from a common
point 22, which will be positioned adjacent to the inflow end of a
replacement valve. The arms 20 are shown as being generally the
same length as each other in this figure, which will be adaptable
to the implantation location of most replacement valves. It is
possible, however, that at least one of the arms 20 is a different
length than the other arms 20, such as in cases where particular
anatomical needs of a patient need to be accommodated, when certain
anchoring techniques are used, or when other considerations of the
patient, the valve, or the delivery systems need to be considered,
for example. The three arms 20 can be angularly displaced
approximately 120 degrees from one another so that they are evenly
spaced around the perimeter of the stent 18; however, it may
instead be desirable to position the arms 20 at different angular
spacings from each other.
[0048] In one embodiment of the invention, one or more of the arms
20 further include outwardly extending barbs or connectors 24 at an
outflow end 14 of the stent 18. These connectors 24 are designed to
engage with the wall of the aorta or other tissue structure in
which the stent 18 may be positioned. Connectors 24 can include a
wide variety of configurations and features, such as the
arrow-shaped tips shown, or other configurations that provide for
engagement with tissue through a piercing or other similar motion,
and further do not allow the connector to disengage from the tissue
with normal movement of the stent within the tissue. Each of the
arms 20 of this embodiment are shown as including two barb-like
connectors 24; however, more or less than two connectors 24 may
extend from a single arm 20, and each of the arms 20 of a stent 18
may include the same or a different number of connectors 24.
[0049] The stent 18 is constructed of a material that is
sufficiently flexible that it can be collapsed for percutaneous
insertion into a patient. The material is also preferably
self-expanding (e.g., Nitinol) such that it can be readily
compressed and re-expanded. The material should further be chosen
so that when the stent 18 is positioned within an aorta, for
example, it exerts sufficient pressure against the aortic walls
that fluids cannot leak past the stent 18. In particular, the stent
18 should provide enough radial outward force so that the tips or
ends of the fold material of a tri-lobed structure can press
against the inside walls of an aorta or other structure of a
patient in such a way that blood cannot flow past these tips of the
replacement valve. In this and any of the embodiments of the
invention, the replacement valves and associated stents can be
provided in a variety of sizes to accommodate the size requirements
of different patients.
[0050] FIG. 6 illustrates the stent 18 of FIG. 5 mounted inside a
valve 16 of the type illustrated in FIG. 4 to provide a completed
replacement valve 26. As shown, the ends of the arms 20 extend
beyond the ends of the valve 16 at the outflow end 14 of the valve;
therefore, an area of the stent 18 relatively near the common point
22 (not visible in this figure) is positioned adjacent to the
inflow end 12 of the valve 26. The adjacent tissue portions of the
lobes at both the inflow end 12 and the outflow end 14 of the
replacement valve 26 can be sewed or otherwise connected to each
other, such as by sutures 10, in order to prevent or minimize the
possibility of blood entering the slots 8 (see FIG. 2) of the
tri-lobed structure.
[0051] The stent 18 is preferably retained in position within the
slots 8 of aortic wall 4 by means of adhesive, sutures or other
surgical fasteners. In one exemplary construction, the stent 18 is
positioned within the slots 8 before the tissue is sutured or
attached to itself at one or both of the inflow and outflow ends
12, 14. When the tissue at the inflow end 12 is sutured, the
adjacent stent 18 can be sutured to the valve 26 at the same time,
such that one stitching operation can serve the dual purpose of
sealing the inflow end 12 of the valve 26 and also securing the
stent 18 to the valve 26.
[0052] Referring now to FIG. 7, a replacement valve of the type
generally shown as the valve 26 in FIG. 6 is illustrated, as
mounted in an aortic annulus 28 of a patient. The valve 26 is
positioned so that the free edges 6 of the leaflets 2 contact the
annulus 28 around at least a substantial portion of the
circumference of the aortic annulus 28, and preferably contact the
annulus 28 around its entire circumference. The valve 26 is further
positioned along the length of the aorta so that the connectors 24
are above the sinuses of Valsalva 32 and adjacent to a wall 30 of
the patient's aorta. The connectors 24 are shown here as being
slightly spaced from the wall 30, such as when the valve 26 is in
an at least slightly compressed or unexpanded state. However, the
arms 20 will be move or be forced to move at least slightly outward
toward the walls 30 until the connectors 24 are imbedded or engaged
with at least a portion of the thickness of the walls 30. These
connectors 24 will then serve the purpose of retaining the valve 26
in its desired implant location relative to the aorta. In one
embodiment, the connectors 24 can be designed to extend through the
entire thickness of the walls 30 such that they will basically be
anchored to the outside surface of the aortic walls 30.
Alternatively, the connectors may be designed to extend only
through a portion of the thickness of the walls 30, which, in order
to keep the valve 26 securely in place, may require a different
style of connector than a connector that extends entirely through
an aortic wall. That is, connectors that need to engage within the
thickness of a tissue can include a number of barbs or tissue
engaging structures on each connector, while a connector that
extends all the way through the tissue may only need to have a
relatively wide base that will not easily pass backward through the
hole it created when originally passing through the tissue.
[0053] In order to prevent possible interference between the
patient's native valve and a replacement valve of the type
illustrated in FIG. 6, for example, the native valve can be
completely or partially removed. In some cases, the native valve
may be left in its original location; however, the replacement
valve in such a circumstance should be positioned in such a way
that the remaining native valve does not interfere with its
operation. In cases where the native valve is to be removed,
exemplary valve removal or resection devices that can be used are
described, for example, in PCT Publication WO/0308809A2, which is
incorporated herein by reference in its entirety.
[0054] FIGS. 8-10 illustrate an end portion of one exemplary
delivery device and exemplary sequential steps for using such a
device for delivering a replacement valve 26 to its desired
location within a patient. In particular, FIG. 8 illustrates a
tubular delivery device 34 that has been advanced to the general
location where the replacement valve 26 will be implanted. In order
to reach this location, the delivery device 34 is inserted into the
body using one of a number of different approaches. For example,
the device 34 can reach the aorta through a retrograde approach
originating at a location distal to the heart, such as the femoral
artery. Alternatively, an antegrade approach could be used, which
originates at a location distal to the heart, such as the femoral
vein or an incision in the ventrical wall or apex. In any case, the
device 34 is moved to the desired implantation area of the body
with a replacement valve 26 being partially or entirely enclosed
within an outer sheath 35. As shown in the figure, the portion of
sheath 35 at the distal end of device 34 is at least slightly
larger in diameter than the adjacent portion of the device 34,
which will help to keep the valve 26 positioned near the distal end
of device 34 (i.e., keep it from translating along the length of
the device 34). However, the distal end of the sheath 35 may
additionally or alternatively include a stop or some other
configuration that keeps the valve 26 from migrating away from the
distal end of device 34.
[0055] With particular reference to FIG. 8, the replacement valve
26 is shown as it is beginning to be advanced out of the end of a
tubular delivery device 34 by pulling back the sheath 35, thereby
releasing or exposing one end of the replacement valve 26. In
accordance with the invention, the valve 26 is delivered in a
radially compressed configuration to ease passage of the device 34
through the vascular system; however, the valve 26 will be able to
expand after it is released from the end of the device 34. The
leaflets 2 of the valve 26 are first are advanced distally out of
the end of the device 34, as illustrated in FIG. 8, so that they
can be properly located relative to the aortic annulus 28. FIG. 9
illustrates the replacement valve 26 as it is further released from
the device 34 by further retraction of the sheath 35. As the
delivery device 34 is withdrawn, the stent 18 of the valve 26 is
allowed to expand and seat the replacement valve 26 in its desired
location.
[0056] Finally, FIG. 10 illustrates the stent of the replacement
valve 26 after the delivery device 34 has been retracted a
sufficient amount that it is completely separated from the valve
26. In this embodiment, the arms 20 are configured so that they
tend to expand radially outwardly once they are released from the
sheath 35. The outward radial force causes the barbs or connectors
24 to embed or otherwise engage with the wall 30 of the patient's
aorta to anchor the replacement valve 26.
[0057] Although the arms 20 are shown as relatively straight wires
in the embodiment of the replacement valve 26 described above, the
stents of the invention may be shaped and/or positioned differently
than previously described. For one example, the stent arms could
instead be curved outwardly (i.e., convex) to conform at least
somewhat to the location of the body in which it will be positioned
(e.g., aorta for aortic valve, pulmonary trunk for the pulmonic
vein, vein for venous valve, and ventricle of mitral/tricuspid
valve). This outward curvature of the stent arms can help to secure
or anchor the valve in place and thus can have different degrees or
amounts of curvature depending on the configuration of the
particular replacement valve. Further, the barbs or connectors that
extend from the stent arms can be positioned near the distal ends
of the arms (i.e., spaced relatively far from the valve, such as
valve 16), as shown and described above, in order for these
connectors to be positioned beyond the sinuses of Valsalva of the
aortic valve of a patient. However, the barbs or connectors could
alternatively or additionally be located closer to the valve, such
as valve 16, which would position the connectors closer to the
outflow end of the replacement valve.
[0058] FIG. 11 illustrates an optional additional use of a balloon
catheter 36 on the delivery device 34 to help to anchor the valve
26 in place in the aorta or other tissue of a patient. In
particular, balloon catheter 36 includes a balloon 38, which is
located radially between the arms 20 of the stent 18 when the
sheath 35 has been retracted from the valve 26. During the process
of inserting the device 34 into the patient, balloon 38 will
generally be at least partially deflated in order to minimize its
size and allow for easier percutaneous insertion of the valve 26.
Once the valve 26 is in its desired location relative to the walls
30 with which it will be engaged, the balloon 38 is inflated via
the balloon catheter 36. The inflation of balloon 38 can be
carefully monitored, such as by measuring pressures of forces, to
expand the arms 20 outwardly by a particular amount, thereby
driving the barbs or connectors 24 toward and into the wall 30 of
the patient's aorta.
[0059] While the procedure illustrated in FIGS. 8-11 illustrates
placement in the aortic annulus using a percutaneous catheter to
deliver the valve retrograde to blood flow, antegrade delivery of
the valve is also within the scope of the invention. Similarly,
while delivery using a catheter is illustrated, the valve could
alternatively be compressed radially and delivered in a minimally
invasive fashion using a tubular surgical trocar or port. In
addition, as noted above and as will be discussed further below,
the valve may be delivered to sites other than the aortic
annulus.
[0060] FIGS. 12 and 13 illustrate alternative replacement valves
that are similar in structure to the valve 26 discussed above, but
include alternative structures for anchoring the replacement valve.
These replacement valves are again shown in the general location in
which they will be positioned within an aortic annulus 28 of a
patient. FIG. 12 illustrates a replacement valve that includes the
stent 18 having multiple arms 20, but instead of these arms 20
including barbs or connectors, the arms 20 are stent wires that are
coupled to a slotted-tube type stent ring 40. As is described above
relative to another embodiment, the arms 20 of this embodiment may
also be curved outwardly to conform at least somewhat to the
location of the body in which it will be positioned. This outward
curvature of the stent arms can help to secure or anchor the valve
in place. Delivery of this valve can be performed using a procedure
that is similar to that described above relative to FIGS. 8-11, or
a different method can be used. Alternatively or additionally, some
type of adhesive may be applied to the stent ring or a
biocompatible covering (e.g., fabric, tissue, polymer, and the
like) to help to keep the stent in place. In any case, stent ring
40 may be self-expanding or may be expanded by a balloon or other
device that can radially expand the ring 40.
[0061] FIG. 13 illustrates a replacement valve that again includes
the stent 18 having multiple arms 20. In this embodiment, the arms
20 are coupled to a stent 42 that is formed of one or more zig-zag
wires. The wires are arranged relative to each other in such a way
that they provide sufficient radial strength to keep the valve in
place relative to the aortic annulus 28 or other location to which
the valve is delivered. Again, delivery of this valve can be
performed using a procedure that is similar to that described above
relative to FIGS. 8-11, or a different method can be used. In any
case, stent 42 may be self-expanding or may be expanded by a
balloon or other device that can radially expand the stent 42.
[0062] FIG. 14 illustrates another embodiment of the replacement
valve 26 of FIG. 6. In particular, a replacement valve 43 is shown,
which includes the same basic structure of the aortic valve 3 of
FIG. 2, and further including the stent 18 including arms 20, as in
FIG. 5. The tips of the arms 20 of stent 18 are located in the
slots 8 and are visible in this top view of the valve 43. The valve
43 further includes optional bulbous portions 44 that extend from
each of the tips of the lobes of the tri-lobed structure of the
valve 43. These portions 44 are provided to further insure secure
contact between the valve 43 and the aorta or other structure in
the areas adjacent to the leaflets 2, thereby further minimizing or
preventing leakage adjacent the valve commissures. These portions
44 may be made of a tissue, fabric, or other material, as
desired.
[0063] FIG. 15 illustrates a replacement valve 48, which includes
an alternative structure to provide valve leaflets. In this
embodiment, leaflets 50 are cut or otherwise formed from a natural
or synthetic flexible material (e.g., pericardial tissue, polymeric
material, fabric, and the like), and are attached to multiple arms
52 of a stent via sutures, glue, or some other attachment material
or method. The leaflets 50 are further attached to one another by
means of sutures 54 to define a generally cup-shaped structure. The
valve leaflets 50 comprise the regions of the cup-shaped structure
located between the longitudinally extending arms 52 of the stent.
The arms 52 of the stent can correspond generally to the arms 20 of
the stent of FIG. 5, or can be arranged and configured differently.
The stent and leaflets could also be constructed together using
processes and materials disclosed, for example, in U.S. Pat. Nos.
6,458,153; 6,652,578; and 7,018,408 (all to Bailey et al.), which
are incorporated herein by reference. In this embodiment of FIG.
15, the arms 52 are coupled to an expandable slotted tube type
stent 56, which may be self-expanding or balloon-expandable similar
to the stent 40 of FIG. 12. Other forms of circumferential stents,
barbs, or other structures may be used in addition to or as an
alternative to the slotted tube type stent structure 56 shown in
this figure. Delivery of the valve can correspond generally to the
procedure described above relative to FIGS. 8-11, although other
delivery devices and methods can be used.
[0064] FIG. 16 illustrates another embodiment of a replacement
valve 57, which uses the valve leaflet structure of FIG. 15 with a
different anchoring embodiment in place of the stent 56. In
particular, replacement valve 57 includes stent arms 56a that
correspond generally to those of the stent 18 described above, but
do not extend as far past the outflow end of the replacement valve
as the stent arms of the replacement valve 26 of FIG. 6. Because
the valve leaflets 50 of this embodiment present an essentially
planar circular free edge, the stent may be anchored to tissue
closely adjacent the aortic valve annulus. Barbs, connectors,
and/or various forms of circumferential stents may be used in
combination with the stent arms 56a to anchor the replacement valve
57 in place. Delivery of the valve 57 can correspond generally to
the procedure described above relative to FIGS. 8-11, although
other delivery devices and methods can be used.
[0065] In the embodiments of FIGS. 15 and 16 described above, the
stent arms are illustrated as being positioned in the interior
portion of the cup-shaped structure; however, the arms could
alternatively be positioned and attached on the outside of the
cup-shaped structure. Attachment of the stent to the valve
structure could be accomplished by suturing, perforating the wire
through the leaflets, adhering, welding, and the like. In any of
these embodiments, the method used to attach the leaflets to each
other in a cup-shaped structure may be the same or different than
the method used to attach a stent either to the inside or outside
of this cup-shaped structure
[0066] FIG. 18 illustrates another embodiment of a replacement
valve 100, which can be fabricated from a piece of flexible tubing,
such as is shown in FIG. 17 as a flexible tube 102. Flexible tube
102 may be a natural or synthetic material, such as pericardial
tissue, for example (which is discussed, for example, in U.S. Pat.
No. 5,482,424, the contents of which are incorporated herein by
reference). Replacement valve 100 utilized the flexible tube 102,
which is sutured to itself by sutures 60 at an inflow end 104,
although other attachment methods may additionally or alternatively
be used, such as adhesive or other surgical fasteners. The
attachment of the tube 102 to itself produces a tri-lobed structure
much like that of the inflow end of the aortic wall 4 of the
replacement valve 26 of FIG. 6. However, in this embodiment, the
flexible tube 102 is not sutured or attached to itself at an
outflow end 106.
[0067] The valve 100 further includes a stent that is similar to
the stent 18 illustrated in FIGS. 5 and 6, which includes multiple
extending arms 20. In this embodiment, the tube 102 is mounted so
that the arms 20 extend through slots in the tri-lobed structure
and can be attached thereto by sutures, adhesives or other means.
However, other stent configurations can also be used, such as using
three separate straight wires in substitution for arms 20, which
wires can be mounted within the lobes of the tube 102 in its
tri-lobed configuration. In any case, the arms 20 or other stent
structures can include barbs or connectors 24 for attachment to the
walls of an aortic annulus or other tissue structure. As with other
embodiments of replacement valve attachment discussed above,
self-expanding or balloon expandable stents may alternatively or
additionally be attached to or extend from arms 20 for attachment
to tissue of a patient.
[0068] In this embodiment of a replacement valve 100, the outflow
end 106 is not sealed to itself, allowing the downstream portion of
the tube located between the arms 20 of the stent 18 to serve as
the leaflets of the valve. That is, the replacement valve 100 is
illustrated in FIG. 18 in its open position, where blood can flow
past the outer surfaces of the valve from the inflow end 104 toward
the outflow end 106. Delivery of the valve corresponds to the
procedure illustrated in FIGS. 8-11. When the replacement valve 100
is in its closed, position, the outflow end 106 essentially flares
outwardly toward the walls of the aorta or other structure in which
it is positioned, as will be discussed in further detail below.
[0069] FIG. 19 is a top view of the replacement valve 100 of FIG.
18, as located within a patient's aortic annulus 62. In this view
it can be seen that the free end of the tube, in conjunction with
the arms 20 of the stent 18, define three leaflets 64. In order for
the leaflets 64 to properly close, it is desirable to have an entry
point for backflow of blood to enter the interior of the tube to
expand the leaflets 64. For this reason, the stent and leaflets of
this embodiment can be sized so that a small central opening 66
remains open to the interior of the tube, even when the valve is
open as illustrated. The same construction may be applied to valves
48 and 57 described above and illustrated in FIGS. 15 and 16.
[0070] FIGS. 20-22 illustrate additional exemplary embodiments of
the replacement valve of FIGS. 18 and 19. In particular, FIG. 20 is
a top view of a replacement valve 110 that allows for fluid entry
into the interior of the tube facilitated by a small cylindrical or
conical lumen 69, which is mounted in the interior portion of the
stent. Lumen 69 acts as a type of a spacer to keep the leaflets 64
freely moveable relative to each other, thereby facilitating
closing of the valve 110 with sufficient pressure from blood flow.
That is, when the blood flow moves in a "backward direction
relative to the pumping blood flow, it should move the leaflets 64
apart from each other and toward the aortic annulus or other
structure in which it is positioned, thereby closing the valve
110.
[0071] FIG. 21 is a top view of a replacement valve 120 that allows
for fluid entry into the interior portion of the tube at the
commissures of leaflets 64 to facilitate closing of the valve 120.
Small openings between the lobes of the structure are provided by
means of enlarged segments on the arms 20a of the stent. FIG. 22
illustrates an enlarged detail of a portion of the embodiment of
FIG. 21. In this view, an enlarged cross section portion of arm 20a
of the stent and the associated small opening 68 are visible. All
of these alternative constructions of FIGS. 20-22 may be applied to
valves 48 and 57 described above and illustrated in FIGS. 15 and
16, along with other valves. Other structures may be used in
addition to or instead of the devices of FIGS. 19-22, any of which
should facilitate the closing of the valve.
[0072] FIG. 23 illustrates a replacement valve 130 that can be
fabricated from the tube 102 of FIG. 17, for example. Valve 130 has
its inflow end 122 sutured to itself to produce a flattened
structure and is mounted to a stent. The stent may be a
self-expanding stent taking the form of a u-shaped wire 70 having
laterally extending barbs 72. The contours of the wires 70 can also
be used to further secure the valve into its position within the
patient. Alternatively, the stent may comprise two separate
straight wires. The free end of the tube in conjunction with the
stent defines two valve leaflets 74 which, when open, expand
against the vessel or orifice in which the replacement valve is
mounted. Delivery of the valve corresponds to the procedure
illustrated in FIGS. 8-11, although other delivery devices and
methods can instead be used.
[0073] FIG. 24 illustrates a detail of the replacement valve 130 of
FIG. 23. As with the valve of FIG. 18, an inflow opening into the
interior of the valve may be desirable to facilitate separation of
the valve portions from each other to close the valve 130. In some
embodiments, this might be provided by enlarged cross section
portions of the wire 70. In alternative embodiments in which the
free edges of leaflets are attached directly to a valve orifice 76,
a simple staple 78 may be substituted, also providing an opening
into the valve 130. Staple 78 may be attached to the stent and may
self expand into the tissue of the annulus or may be balloon
expanded, for example.
[0074] FIG. 25 illustrates the replacement valve 130 of FIG. 23,
which is folded to allow passage through a catheter or other
tubular delivery device. In this embodiment, the u-shaped stent
wire 70 or other stent configuration is coupled to an expandable
stent 80. By folding the replacement valve 130 rather than
circumferentially compressing it, stress on the valve 130 is
reduced.
[0075] FIG. 26 illustrates an alternative stent configuration 79
for use with the leaflets of the above FIGS. 15-24. In this design,
rather than employing multiple curved, longitudinally extending
arms or wires, a single longitudinally extending wire 86 is used.
Wire 86 includes an enlarged base 88 against which the inflow end
of the valve leaflets rest. The commissures and thus the valve
leaflets 80 are defined by two or three laterally extending wires
82, which are attached to the edges of the valve leaflets 80. The
laterally extending wires 82 are provided with barbs or connectors
84 which anchor the replacement valve in place within the vessel or
orifice in which it is implanted.
[0076] FIGS. 27 and 28 illustrate additional features that can be
used with a replacement valve of the type described relative to
valve 130. In particular, a replacement valve 140 is formed from a
tube of material to create a bicuspid valve structure, as in FIG.
23. The valve has its inflow end sutured to itself to produce a
flattened structure with a central longitudinal opening 148 in
which a stent 146 is positioned. Again, the stent 146 may take the
shape of a u-shaped wire with laterally extending barbs or
connectors, or another stent configuration can be used. In any
case, the stent 146 of this embodiment works in conjunction with
the size of the slot 148 to provide at least a slight gap between
the opposing leaflets 144. The slot 148 helps to facilitate opening
of the leaflets 144 when the blood flows from the outflow end of
the valve toward the inflow end, thereby closing the valve 140.
[0077] FIG. 28 illustrates a replacement valve 150 that is similar
to valve 140, except that valve 150 includes a slot 152 that is not
particularly designed to include a space between opposing leaflets
154. In order to facilitate separation of the leaflets 154, this
valve 150 includes pockets 156 at both ends, which can be formed by
the ends 158 of a stent positioned therein. For example, these ends
158 may be enlarged relative to the stent wire so that the stent
can operate in its normal manner while the enlarged ends operate to
form the pockets 156.
[0078] While a number of the valves described above are shown as
having fixation barbs located downstream of the free edges of the
valve leaflets, this need not necessarily be so. In fact, the
planar, generally circular configuration of the free edges of the
valve leaflets in the closed position would in some cases allow the
barbs or connectors to extend outward through or adjacent to the
free edges of the valves. Further, while the discussion of the
valves above focuses mainly on placement in the aortic annulus, the
valves may be employed in other locations including replacement of
other heart valves and peripheral venous valves. Finally, while the
valves as disclosed are described mainly in the context of
percutaneously or minimally invasively delivered valves, they could
also be placed surgically.
[0079] The present invention has now been described with reference
to several embodiments thereof. The foregoing detailed description
and examples have been given for clarity of understanding only. No
unnecessary limitations are to be understood therefrom. It will be
apparent to those skilled in the art that many changes can be made
in the embodiments described without departing from the scope of
the invention. Thus, the scope of the present invention should not
be limited to the structures described herein.
* * * * *