U.S. patent application number 14/662464 was filed with the patent office on 2015-10-01 for transcatheter mitral valve stent frames.
The applicant listed for this patent is ST. JUDE MEDICAL, CARDIOLOGY DIVISION, INC.. Invention is credited to Thomas Mark Benson, Theodore Paul Dale, Jason Diedering, Saravana B. Kumar, Andrea N. Para, Gaurav Satam.
Application Number | 20150272737 14/662464 |
Document ID | / |
Family ID | 52823806 |
Filed Date | 2015-10-01 |
United States Patent
Application |
20150272737 |
Kind Code |
A1 |
Dale; Theodore Paul ; et
al. |
October 1, 2015 |
TRANSCATHETER MITRAL VALVE STENT FRAMES
Abstract
A prosthetic heart valve may include a stent having an inflow
end, an outflow end, a collapsed condition, and an expanded
condition. The prosthetic valve may also include a collapsible and
expandable valve assembly disposed within the stent and having a
plurality of leaflets. The prosthetic valve and/or stent may
include features to anchor the prosthetic valve to a native valve
annulus and to seal the prosthetic valve with respect to the native
valve annulus, such as planar and/or nonplanar annular sealing
members coupled to ends of the stent. The stent may include one or
more circumferential rows of anchor members or hooks extending
radially outwardly from the stent. These hooks may be configured to
extend in a particular direction when the stent is in the collapsed
condition to facilitate resheathing of the stent if, upon
deployment, a user determines the prosthetic heart valve is not
positioned optimally.
Inventors: |
Dale; Theodore Paul;
(Corcoran, MN) ; Para; Andrea N.; (Plymouth,
MN) ; Satam; Gaurav; (Falcon Heights, MN) ;
Diedering; Jason; (Minneapolis, MN) ; Benson; Thomas
Mark; (Minneapolis, MN) ; Kumar; Saravana B.;
(Otsego, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ST. JUDE MEDICAL, CARDIOLOGY DIVISION, INC. |
St. Paul |
MN |
US |
|
|
Family ID: |
52823806 |
Appl. No.: |
14/662464 |
Filed: |
March 19, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61970443 |
Mar 26, 2014 |
|
|
|
Current U.S.
Class: |
623/2.37 ;
623/2.4 |
Current CPC
Class: |
A61F 2/2409 20130101;
A61F 2220/0008 20130101; A61F 2/2445 20130101; A61F 2/2418
20130101; A61F 2220/0016 20130101; A61F 2230/0069 20130101; A61F
2230/0065 20130101; A61F 2/2442 20130101 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A prosthetic heart valve, comprising: a stent having an inflow
end, an outflow end, a center portion between the inflow end and
the outflow end, a collapsed condition, and an expanded condition;
a collapsible and expandable valve assembly disposed within the
stent and having a plurality of leaflets; a first annular sealing
member coupled to the inflow end; and a second annular sealing
member coupled to the outflow end.
2. The prosthetic heart valve of claim 1, wherein the first and
second sealing members each have a diameter greater than a diameter
of the stent when the stent is in the expanded condition.
3. The prosthetic heart valve of claim 2, wherein the stent is
substantially cylindrical in the expanded condition.
4. The prosthetic heart valve of claim 2, wherein the first sealing
member has a substantially planar configuration when the stent is
in the expanded condition.
5. The prosthetic heart valve of claim 2, wherein the inflow end
and the outflow end of the stent each has a diameter greater than a
diameter of the center portion of the stent when the stent is in
the expanded condition.
6. The prosthetic heart valve of claim 2, wherein the first sealing
member is substantially nonplanar when the stent is in the expanded
condition.
7. The prosthetic heart valve of claim 6, wherein an outer
perimeter of the first sealing member is closer to the outflow end
than an inner perimeter of the first sealing member when the stent
is in the expanded condition.
8. The prosthetic heart valve of claim 6, wherein an outer
perimeter of the second sealing member is closer to the inflow end
than an inner perimeter of the second sealing member when the stent
is in the expanded condition.
9. A stent having an expanded condition and a collapsed condition,
comprising: a substantially cylindrical body having a first end and
a second end; a flared portion coupled to the first end of the body
and extending radially outwardly from the body and away from the
second end of the body when the stent is in the expanded condition;
and a plurality of anchor members each having a first end coupled
to the body and a second free end extending radially outwardly from
the body and toward the first end of the body when the stent is in
the expanded condition, wherein the flared portion and the second
free ends of the anchor members are configured to extend away from
the second end of the body when the stent is in the collapsed
condition.
10. The stent of claim 9, wherein the flared portion and the body
are each formed of a plurality of struts that form cells having an
area, the area of each cell of the body being greater than the area
of each cell of the flared portion when the stent is in the
expanded condition.
11. The stent of claim 9, wherein the flared portion and the body
are each formed of a plurality of struts having a thickness, the
thickness of the struts forming the flared portion being less than
the thickness of the struts forming the body.
12. A stent having an expanded condition and a collapsed condition,
comprising: a substantially cylindrical center body having a first
end and a second end; a first plurality of anchor members each
having a first end coupled to the first end of the body and a
second free end extending radially outwardly from the body and
toward the second end of the body when the stent is in the expanded
condition; and a second plurality of anchor members each having a
first end coupled to the body and a second free end extending
radially outwardly from the body and toward the second end of the
body when the stent is in the expanded condition, wherein the first
and second plurality of anchor members are configured to extend
toward the second end of the body when the stent is in the
collapsed condition.
13. A stent having an expanded condition and a collapsed condition,
comprising: a substantially cylindrical center body having a first
end and a second end; a first plurality of anchor members each
having a first end coupled to the body and a second free end
extending radially outwardly from the body and toward the first end
of the body when the stent is in the expanded condition; and a
second plurality of anchor members each having a first end coupled
to the first end of the body and a second free end extending
radially outwardly from the body and toward the second end of the
body when the stent is in the expanded condition, wherein the first
plurality of anchor members extend toward the first end of the body
and the second plurality of anchor members extend toward the second
end of the body when the stent is in the collapsed condition.
14. The stent of claim 13, wherein the second plurality of anchor
members includes a first group of anchor members and a second group
of anchor members, the first group being configured to engage a
native posterior mitral valve leaflet and the second group being
configured to engage a native anterior mitral valve leaflet when
the stent is implanted in a native mitral valve annulus of a
patient.
15. A stent having an expanded condition and a collapsed condition,
comprising: a substantially cylindrical center body having a first
end, a second end, and a longitudinal axis extending between the
first end and the second end; a first plurality of anchor members
each having a first end coupled to the body and a second free end
extending radially outwardly from the body and substantially
perpendicular to the longitudinal axis of the body when the stent
is in the expanded condition; and a second plurality of anchor
members each having a first end coupled to the body and a second
free end extending radially outwardly from the body and
substantially perpendicular to the longitudinal axis of the body
when the stent is in the expanded condition, wherein the first
plurality of anchor members extend away from the second end of the
body and the second plurality of anchor members extend away from
the first end of the body when the stent is in the collapsed
condition.
16. The stent of claim 15, further comprising: a plurality of
struts forming a first circumferential row of cells and a second
circumferential row of cells, wherein each of the first plurality
of anchor members is at least partially formed from one of the
cells in the first circumferential row and each of the second
plurality of anchor members is at least partially formed from one
of the cells in the second circumferential row.
17. A prosthetic heart valve, comprising: a stent having an inflow
end, an outflow end, a collapsed condition, and an expanded
condition, the stent being formed from wire and having a first
series of hooks and a second series of hooks; and a cuff coupled to
the stent, wherein, when the stent is in the expanded condition,
each hook of the first series extends radially outwardly from the
stent at the inflow end and each hook of the second series includes
a first portion that extends radially outwardly from the stent at
the outflow end and a second portion that extends toward the inflow
end.
18. The prosthetic heart valve of claim 17, wherein the cuff has a
first substantially flat portion that spans across and is coupled
to the first series of hooks.
19. A prosthetic heart valve, comprising: a stent having an inflow
end, an outflow end, a collapsed condition, and an expanded
condition, the stent being formed of a plurality of struts; a
collapsible and expandable valve assembly disposed within the stent
and having a plurality of leaflets; and a commissure attachment
feature attached to at least one of the plurality of struts and
positioned between the inflow end and the outflow end when the
stent is in the expanded condition.
20. The prosthetic heart valve of claim 19, wherein the commissure
attachment feature has a first end attached to at least one of the
plurality of struts and a second free end extending toward the
inflow end when the stent is in the expanded condition.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of the filing
date of U.S. Provisional Patent Application No. 61/970,443 filed
Mar. 26, 2014, the disclosure of which is hereby incorporated
herein by reference.
BACKGROUND
[0002] The present disclosure relates to heart valve replacement
and, in particular, to collapsible prosthetic heart valves. More
particularly, the present disclosure relates to designs for stent
frames for collapsible prosthetic heart valves.
[0003] Prosthetic heart valves that are collapsible to a relatively
small circumferential size can be delivered into a patient less
invasively than valves that are not collapsible. For example, a
collapsible valve may be delivered into a patient via a tube-like
delivery apparatus such as a catheter, a trocar, a laparoscopic
instrument, or the like. This collapsibility can avoid the need for
a more invasive procedure such as full open-chest, open-heart
surgery.
[0004] Collapsible prosthetic heart valves typically take the form
of a valve structure mounted on a stent. There are two types of
stents on which the valve structures are ordinarily mounted: a
self-expanding stent and a balloon-expandable stent. To place such
valves into a delivery apparatus and ultimately into a patient, the
valve is generally first collapsed or crimped to reduce its
circumferential size.
[0005] When a collapsed prosthetic valve has reached the desired
implant site in the patient (e.g., at or near the annulus of the
patient's heart valve that is to be replaced by the prosthetic
valve), the prosthetic valve can be deployed or released from the
delivery apparatus and re-expanded to full operating size. For
balloon-expandable valves, this generally involves releasing the
entire valve, assuring its proper location, and then expanding a
balloon positioned within the valve stent. For self-expanding
valves, on the other hand, the stent automatically expands as the
sheath covering the valve is withdrawn.
BRIEF SUMMARY
[0006] According to one embodiment of the disclosure, a prosthetic
heart valve may include a stent having an inflow end, an outflow
end, a center portion between the inflow end and the outflow end, a
collapsed condition, and an expanded condition. A collapsible and
expandable valve assembly may be disposed within the stent and may
have a plurality of leaflets. A first annular sealing member may be
coupled to the inflow end and a second annular sealing member may
be coupled to the outflow end.
[0007] According to another embodiment of the disclosure, a stent
having an expanded condition and a collapsed condition may include
a substantially cylindrical body having a first end and a second
end. A flared portion may be coupled to the first end of the body
and may extend radially outwardly from the body and away from the
second end of the body when the stent is in the expanded condition.
A plurality of anchor members may each have a first end coupled to
the body and a second free end extending radially outwardly from
the body and toward the first end of the body when the stent is in
the expanded condition. The flared portion and the second free ends
of the anchor members may be configured to extend away from the
second end of the body when the stent is in the collapsed
condition.
[0008] According to a further embodiment of the disclosure, a stent
having an expanded condition and a collapsed condition may include
a substantially cylindrical center body having a first end and a
second end. A first plurality of anchor members may each have a
first end coupled to the first end of the body and a second free
end extending radially outwardly from the body and toward the
second end of the body when the stent is in the expanded condition.
A second plurality of anchor members may each have a first end
coupled to the body and a second free end extending radially
outwardly from the body and toward the second end of the body when
the stent is in the expanded condition. The first and second
plurality of anchor members may be configured to extend toward the
second end of the body when the stent is in the collapsed
condition.
[0009] According to still another embodiment of the disclosure, a
stent having an expanded condition and a collapsed condition may
include a substantially cylindrical center body having a first end
and a second end. A first plurality of anchor members each having a
first end coupled to the body and a second free end may extend
radially outwardly from the body and toward the first end of the
body when the stent is in the expanded condition. A second
plurality of anchor members each having a first end coupled to the
first end of the body and a second free end may extend radially
outwardly from the body and toward the second end of the body when
the stent is in the expanded condition. The first plurality of
anchor members may extend toward the first end of the body and the
second plurality of anchor members may extend toward the second end
of the body when the stent is in the collapsed condition.
[0010] According to yet another embodiment of the disclosure, a
stent having an expanded condition and a collapsed condition may
include a substantially cylindrical center body having a first end,
a second end, and a longitudinal axis extending between the first
end and the second end. A first plurality of anchor members may
each have a first end coupled to the body and a second free end
extending radially outwardly from the body and substantially
perpendicular to the longitudinal axis of the body when the stent
is in the expanded condition. A second plurality of anchor members
may each have a first end coupled to the body and a second free end
extending radially outwardly from the body and substantially
perpendicular to the longitudinal axis of the body when the stent
is in the expanded condition. The first plurality of anchor members
may extend away from the second end of the body and the second
plurality of anchor members may extend away from the first end of
the body when the stent is in the collapsed condition.
[0011] According to yet a further embodiment of the disclosure, a
prosthetic heart valve may include a stent having an inflow end, an
outflow end, a collapsed condition, and an expanded condition. The
stent may be formed from wire and may have a first series of hooks
and a second series hooks. A cuff may be coupled to the stent. When
the stent is in the expanded condition, each hook of the first
series may extend radially outwardly from the stent at the inflow
end and each hook of the second series may include a first portion
that extends radially outwardly from the stent at the outflow end
and a second portion that extends toward the inflow end.
[0012] According to an even further embodiment of the disclosure, a
prosthetic heart valve may include a stent having an inflow end, an
outflow end, a collapsed condition, and an expanded condition. The
stent may be formed of a plurality of struts. A collapsible and
expandable valve assembly may be disposed within the stent and may
have a plurality of leaflets. A commissure attachment feature may
be attached to at least one of the plurality of struts and may be
positioned between the inflow end and the outflow end when the
stent is in the expanded condition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Various embodiments of the present disclosure are described
herein with reference to the drawings, wherein:
[0014] FIG. 1 is a schematic cutaway representation of a human
heart showing a transapical delivery approach;
[0015] FIG. 2 is a schematic representation of a native mitral
valve and associated cardiac structures;
[0016] FIG. 3A is a side view of a prosthetic heart valve according
to the prior art;
[0017] FIG. 3B is a longitudinal cross-section of the prosthetic
heart valve of FIG. 3A;
[0018] FIG. 4A is a schematic perspective view of a prosthetic
heart valve according to the present disclosure;
[0019] FIG. 4B is a longitudinal cross-section of the prosthetic
heart valve of FIG. 4A;
[0020] FIG. 4C is a schematic representation of the prosthetic
heart valve of FIG. 4A disposed in a native valve annulus;
[0021] FIG. 5A is a schematic cut-away perspective view of another
prosthetic heart valve according to the present disclosure;
[0022] FIG. 5B is a longitudinal cross-section of the prosthetic
heart valve of FIG. 5A;
[0023] FIG. 5C is a schematic representation of the prosthetic
heart valve of FIG. 5A disposed in a native valve annulus;
[0024] FIG. 6A is a schematic perspective view of a docking station
for use with a prosthetic heart valve;
[0025] FIG. 6B is a cross-sectional view of the docking station of
FIG. 6A;
[0026] FIG. 6C is a schematic representation of the docking station
of FIG. 6A disposed in a native valve annulus with a prosthetic
heart valve disposed within the docking station.
[0027] FIG. 7A is a perspective view of a stent of a prosthetic
heart valve according to the present disclosure;
[0028] FIG. 7B is a schematic representation of the stent of FIG.
7A disposed in a native valve annulus;
[0029] FIG. 7C is a perspective view of another stent of a
prosthetic heart valve according to the present disclosure;
[0030] FIG. 7D is a schematic representation of the stent of FIG.
7C disposed in a native valve annulus;
[0031] FIG. 8A is a side view of another stent of a prosthetic
heart valve according to the present disclosure;
[0032] FIG. 8B is a schematic representation of the stent of FIG.
8A disposed in a native valve annulus;
[0033] FIG. 9 is a developed view of a further stent of a
prosthetic heart valve according to the present disclosure;
[0034] FIG. 10 is a perspective view of yet another stent of a
prosthetic heart valve according to the present disclosure;
[0035] FIG. 11 is a perspective view of another prosthetic heart
valve according to the present disclosure;
[0036] FIG. 12 is a side view of a further prosthetic heart valve
according to the present disclosure; and
[0037] FIG. 13 is a perspective view of still another stent of a
prosthetic heart valve according to the present disclosure.
[0038] Various embodiments of the present disclosure will now be
described with reference to the appended drawings. It is to be
appreciated that these drawings depict only some embodiments of the
disclosure and are therefore not to be considered limiting of its
scope.
DETAILED DESCRIPTION
[0039] Blood flows through the mitral valve from the left atrium to
the left ventricle. As used herein, the term "inflow end," when
used in connection with a prosthetic mitral heart valve, refers to
the end of the heart valve closest to the left atrium when the
heart valve is implanted in a patient, whereas the term "outflow
end," when used in connection with a prosthetic mitral heart valve,
refers to the end of the heart valve closest to the left ventricle
when the heart valve is implanted in a patient. Further, when used
herein with reference to a delivery device, the terms "proximal"
and "distal" are to be taken as relative to a user using the device
in an intended manner. "Proximal" is to be understood as relatively
close to the user and "distal" is to be understood as relatively
farther away from the user. Also, as used herein, the terms
"substantially," "generally," and "about" are intended to mean that
slight deviations from absolute are included within the scope of
the term so modified. Generally, materials described as being
suitable for components in one embodiment may also be suitable for
similar components described in other embodiments.
[0040] FIG. 1 is a schematic cutaway representation of human heart
100. The human heart includes two atria and two ventricles: right
atrium 112 and left atrium 122, and right ventricle 114 and left
ventricle 124. Heart 100 further includes aorta 110, and aortic
arch 120. Disposed between the left atrium and the left ventricle
is mitral valve 130. Mitral valve 130, also known as the bicuspid
valve or left atrioventricular valve, is a dual-flap that opens as
a result of increased pressure in left atrium 122 as it fills with
blood. As atrial pressure increases above that of left ventricle
124, mitral valve 130 opens and blood passes into left ventricle
124. Blood flows through heart 100 in the direction shown by arrows
"B".
[0041] A dashed arrow, labeled "TA", indicates a transapical
approach of implanting a prosthetic heart valve, in this case to
replace the mitral valve. In transapical delivery, a small incision
is made between the ribs and into the apex of left ventricle 124 to
deliver the prosthetic heart valve to the target site. A second
dashed arrow, labeled "TS", indicates a transseptal approach of
implanting a prosthetic heart valve in which the valve is passed
through the septum between right atrium 112 and left atrium 122.
Other approaches for implanting a prosthetic heart valve are also
possible.
[0042] FIG. 2 is a more detailed schematic representation of native
mitral valve 130 and its associated structures. As previously
noted, mitral valve 130 includes two flaps or leaflets, posterior
leaflet 136 and anterior leaflet 138, disposed between left atrium
122 and left ventricle 124. Cord-like tendons, known as chordae
tendineae 134, connect the two leaflets 136, 138 to the medial and
lateral papillary muscles 132. During atrial systole, blood flows
from higher pressure in left atrium 122 to lower pressure in left
ventricle 124. When left ventricle 124 contracts in ventricular
systole, the increased blood pressure in the chamber pushes
leaflets 136, 138 to close, preventing the backflow of blood into
left atrium 122. Since the blood pressure in left atrium 122 is
much lower than that in left ventricle 124, leaflets 136, 138
attempt to evert to the low pressure regions. Chordae tendineae 134
prevent the eversion by becoming tense, thus pulling on leaflets
136, 138 and holding them in the closed position.
[0043] FIGS. 3A and 3B are a side view and a longitudinal
cross-sectional view of prosthetic heart valve 300 according to the
prior art. Prosthetic heart valve 300 is a collapsible prosthetic
heart valve designed to replace the function of the native mitral
valve of a patient (see native mitral valve 130 of FIGS. 1-2).
Generally, prosthetic valve 300 has a substantially cylindrical
shape with inflow end 310 and outflow end 312. When used to replace
native mitral valve 130, prosthetic valve 300 may have a low
profile so as not to interfere with atrial function in the native
valve annulus.
[0044] Prosthetic heart valve 300 may include stent 350, which may
be formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 350 may include a plurality of struts 352 that form
cells 354 connected to one another in one or more annular rows
around the stent. Cells 354 may all be of substantially the same
size around the perimeter and along the length of stent 350.
Alternatively, cells 354 near inflow end 310 may be larger than the
cells near outflow end 312. Stent 350 may be expandable to provide
a radial force to assist with positioning and stabilizing
prosthetic heart valve 300 in the native valve annulus.
[0045] Prosthetic heart valve 300 may also include a substantially
cylindrical valve assembly 360 including a pair of leaflets 362
(FIG. 3B) attached to a cuff 364 (FIG. 3A). Leaflets 362 replace
the function of native mitral valve leaflets 136 and 138 described
above with reference to FIG. 2. That is, leaflets 362 coapt with
one another to function as a one-way valve. Though prosthetic heart
valve 300 is illustrated as having a valve assembly 360 with two
leaflets 362, it will be appreciated that prosthetic heart valve
300 may have more than two leaflets when used to replace the mitral
valve or other cardiac valves within a patient. Both cuff 364 and
leaflets 362 may be wholly or partly formed of any suitable
biological material, such as bovine or porcine pericardium, or
polymers, such as polytetrafluoroethylene (PTFE), urethanes and the
like. Valve assembly 360 may be secured to stent 350 by suturing to
struts 352 or by using tissue glue, ultrasonic welding or other
suitable methods.
[0046] When prosthetic heart valve 300 is implanted in a patient,
for example at the annulus of native mitral valve 130, it is biased
towards an expanded condition, providing radial force to anchor the
valve in place. However, if the radial force is too high, damage
may occur to heart tissue. If, instead, the radial force is too
low, the heart valve may move from its implanted position, for
example, into either left ventricle 124 or left atrium 122,
requiring emergency surgery to remove the displaced valve. The
potential for such movement may be heightened in mitral valve
applications, particularly if a low profile valve is used.
[0047] Another potential issue with prosthetic heart valves is
inadequate sealing between the prosthetic valve and the native
tissue. For example, if prosthetic heart valve 300 is implanted at
the annulus of mitral valve 130 in a patient, improper or
inadequate sealing may result in blood flowing from left ventricle
124 into left atrium 122, even if leaflets 362 of valve assembly
360 are working properly. This may occur, for example, if blood
flows in a retrograde fashion between the outer perimeter of
prosthetic heart valve 300 and the native tissue at the site of
implantation. This phenomenon is known as perivalvular (or
paravalvular) leak ("PV leak").
[0048] FIGS. 4A and 4B illustrate a prosthetic heart valve 400
according to one embodiment of the disclosure in perspective and
longitudinal cross-section views, respectively. Prosthetic heart
valve 400 is a collapsible prosthetic heart valve designed to
replace the function of the native mitral valve of a patient.
Generally, prosthetic valve 400 has inflow end 410 and outflow end
412.
[0049] Prosthetic heart valve 400 may include stent 450, which may
be formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 450 may include a plurality of struts 452 that form
cells 454 connected to one another in one or more annular rows
around the stent. Stent 450 may be radially expandable to provide a
radial force to assist with positioning and stabilizing prosthetic
heart valve 400 in the native mitral valve annulus. Stent 450 may
be substantially cylindrically shaped when in the expanded
condition.
[0050] Prosthetic heart valve 400 may also include valve assembly
460 including a pair of leaflets 462. Leaflets 462 function
similarly to leaflets 362 described above in connection with FIG.
3B, and more or fewer leaflets may be used in other
applications.
[0051] A number of sealing elements may be provided on prosthetic
heart valve 400. In particular, prosthetic heart valve 400 may
include a first sealing ring 480 positioned at inflow end 410 and a
second sealing ring 490 positioned at outflow end 412. Each sealing
ring 480, 490 may be formed of a biocompatible material that allows
tissue ingrowth. For example, sealing rings 480 and 490 may be
formed of fabrics and/or polymers, such as polytetrafluoroethylene
(PTFE), urethanes and the like. Alternatively, sealing rings 480
and 490 may be formed of traditional stent materials, such as shape
memory alloys including Nitinol, and may take forms including
Nitinol coils. In still other embodiments, sealing rings 480 and
490 may be formed from a metal or polymer mesh or braid. Still
further, sealing rings 480, 490 may be formed of tissue, such as
porcine cardiac tissue. Some or all of the above materials may be
used in combination with a coating, such as a collagen coating, a
fibrin coating, or a polymer coating (such as a silicone coating).
Sealing rings 480 and 490 may be attached to inflow end 410 and
outflow end 412, respectively, by, for example, sutures, adhesives,
ultrasonic welding or other suitable methods. Alternatively, if
sealing rings 480 and 490 are formed of the same material as stent
450, sealing rings 480 and 490 may be formed integrally with stent
450.
[0052] Each sealing ring 480, 490 is generally annular, with a
center portion of each sealing ring being attached to stent 450 so
that blood may flow through the stent. Sealing rings 480 and 490
may each have an outer diameter that is greater than the diameter
of stent 450 when in the expanded condition. When stent 450 is in
the expanded condition, sealing rings 480 and 490 each have a
substantially planar configuration. However, other shapes and sizes
may be suitable depending on the particular anatomy of the patient.
FIG. 4C shows prosthetic heart valve 400 implanted within native
valve annulus VA between left atrium 122 and left ventricle 124. In
the implanted position, first sealing ring 480 is positioned on the
atrial side of native valve annulus VA while second sealing ring
490 is positioned on the ventricular side of native valve annulus
VA. Sealing rings 480 and 490 may help prevent PV leak by
preventing blood from flowing from left ventricle 124 to left
atrium 122 between the native valve annulus VA and the outer
perimeter of prosthetic heart valve 400. This function may be
enhanced once tissue begins to grow into first sealing ring 480 and
second sealing ring 490.
[0053] In addition to helping prevent PV leak, sealing ring 480 may
provide an anchoring effect, helping to prevent prosthetic heart
valve 400 from migrating toward left ventricle 124. Similarly,
second sealing ring 490 may also provide an anchoring effect,
helping to prevent prosthetic heart valve 400 from migrating toward
left atrium 122. This additional anchoring ability may reduce the
radial force required of stent 450 to keep prosthetic heart valve
400 secured in native valve annulus VA, which, in turn, may allow
stent 450 to have a smaller fully expanded diameter than
traditional stents. This reduction in size may be possible, in
part, due to a reduction or elimination of the need to have a
relatively large stent frame to maximize the range of anatomies
which could accept the stent and still have enough radial force to
hold the stent in place. The relatively smaller diameter which may
be possible due to the above-described features may result in lower
hydrodynamic load on prosthetic heart valve 400, which may reduce
the stresses on valve assembly 460 and which also may reduce the
strain on the material forming stent 450.
[0054] FIGS. 5A and 5B illustrate a prosthetic heart valve 500
according to another embodiment of the disclosure. Prosthetic heart
valve 500 is similar to prosthetic heart valve 400 in certain
respects. For example, prosthetic heart valve 500 may include stent
550, which may be formed from biocompatible materials that are
capable of self-expansion, such as, for example, shape memory
alloys including Nitinol. Stent 550 may include a plurality of
struts 552 that form cells 554 connected to one another in one or
more annular rows around the stent. Stent 550 may be radially
expandable to provide a radial force to assist with positioning and
stabilizing prosthetic heart valve 500 in the native valve annulus.
Stent 550 has the general shape of a cylinder, except that it is
bowed inwardly from inflow end 510 and outflow end 512 toward the
center. In other words, stent 550 has a concave shape, wherein the
center of stent 550 has a smaller diameter than that of inflow end
510 and outflow end 512 when in the expanded condition.
[0055] Prosthetic heart valve 500 may also include valve assembly
560 including a pair of leaflets 562. Leaflets 562 function
similarly to leaflets 362 described above in connection with FIG.
3B, and more or fewer leaflets may be used in other
applications.
[0056] Prosthetic heart valve 500 may also include a number of
sealing elements. In particular, prosthetic heart valve 500 may
include a first sealing ring 580 positioned at inflow end 510 and a
second sealing ring 590 positioned at outflow end 512. Sealing
rings 580, 590 may be generally similar to sealing rings 480, 490,
with the exception that first sealing ring 580 is curved toward
outflow end 512 and second sealing ring 590 is curved toward inflow
end 510. In other words, sealing rings 580 and 590 are
substantially non-planar when stent 550 is in the expanded
condition. Sealing rings 580, 590 may be formed of the same
biocompatible materials described above for forming sealing rings
480 and 490, and may be attached to inflow end 510 and outflow end
512, respectively, in the same manner as sealing rings 480 and
490.
[0057] Each sealing ring 580, 590 is generally annular, with a
center portion of each sealing ring being attached to stent 550 so
that blood may flow through the stent. As described above, sealing
rings 580, 590 may be curved away from the ends of stent 550 to
which the rings are attached. In other words, the outer perimeter
of first sealing ring 580 is closer to outflow end 512 than the
inner perimeter of that sealing ring. Similarly, the outer
perimeter of second sealing ring 590 is closer to inflow end 510
than the inner perimeter of that sealing ring. However, other
shapes and sizes may be suitable depending on the particular
anatomy of the patient.
[0058] FIG. 5C shows prosthetic heart valve 500 implanted within
native valve annulus VA between left atrium 122 and left ventricle
124. In the implanted position, first sealing ring 580 is
positioned on the atrial side of native valve annulus VA while
second sealing ring 590 is positioned on the ventricular side of
native valve annulus VA. In these positions, sealing rings 580 and
590 mitigate PV leak by preventing blood from flowing from left
ventricle 124 to left atrium 122 between the native valve annulus
VA and the outer perimeter of prosthetic heart valve 500. Once
tissue begins to grow into first sealing ring 580 and second
sealing ring 590, PV leak may be mitigated to an even greater
extent.
[0059] In addition to helping prevent PV leak, first sealing ring
580 may provide an anchoring effect, helping to prevent prosthetic
heart valve 500 from migrating toward left ventricle 124.
Similarly, second sealing ring 590 may also provide an anchoring
effect, helping to prevent prosthetic heart valve 500 from
migrating toward left atrium 122. The curvature of sealing rings
580 and 590 may dictate, in part, how prosthetic heart valve 500
interacts with the anatomy and how stresses are distributed in
valve 500. The above-described curvature may have an enhanced
effect on sealing and anchoring in comparison to a relatively flat
or planar sealing ring. This may be due, in part, to the anatomy
near the implant site having generally non-planar surfaces.
Further, the curvature of sealing rings 580 and 590 may effectively
pinch tissue of the annulus resulting in enhanced sealing and
anchoring, while also increasing apposition to the annulus by
forcing any irregular anatomic geometries into the pinched area. In
addition, the inwardly bowed shape of stent 550 may provide a
greater contact area between stent 550 and the native valve annulus
VA.
[0060] FIGS. 6A and 6B illustrate a prosthetic heart valve docking
station 600 according to one embodiment of the disclosure in
perspective and longitudinal cross-sectional views, respectively.
As is described below, docking station 600 may first be implanted
in a native valve annulus, and a prosthetic heart valve may be
subsequently implanted in docking station 600.
[0061] Docking station 600 has inflow end 610 and outflow end 612,
and may be formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Docking station 600 may alternatively be made of a
material that is not self-expandable, such as stainless steel,
which may be expanded with the use of a separate expandable
structure, such as a balloon.
[0062] Docking station 600 may have the general form of a hollow
tube with a cylindrical center section 670 and anchoring members
extending radially outwardly at inflow end 610 and outflow end 612.
For example, the illustrated embodiment of docking station 600
includes first anchor rim 680 and second anchor rim 690. The
particular shape of each anchor rim 680, 690 may be varied. For
example, first anchor rim 680 may have a cylindrical outer surface
682 that is substantially concentric to cylindrical center section
670. One end surface 684 of anchor rim 680 coextensive with inflow
end 610 may lie in a plane perpendicular to the axis of rotation of
central section 670. The other end surface 686 of anchor rim 680
may be inclined at an oblique angle to the axis of rotation of
central section 670. Second anchor rim 690 may have a similar
structure. That is, second anchor rim 690 may have a cylindrical
outer surface 692 that is substantially concentric to center
section 670. One end surface 694 of anchor rim 690 coextensive with
outflow end 612 may lie in a plane perpendicular to the axis of
rotation of center section 670, while the other end surface 696 of
anchor rim 690 may be inclined at an oblique angle to that axis of
rotation. The inclined surfaces of anchor rims 680 and 690 may
provide better contact with a native valve annulus, but may be
varied and still be within the scope of this disclosure.
[0063] FIG. 6C shows docking station 600 implanted within native
valve annulus VA between left atrium 122 and left ventricle 124. In
the implanted position, first anchor rim 680 is positioned on the
atrial side of native valve annulus VA while anchor rim 690 is
positioned on the ventricular side of native valve annulus VA.
Anchor rims 680 and 690 may provide an anchoring effect, helping
prevent docking station 600 from migrating toward left ventricle
124 or left atrium 122. Once docking station 600 has been implanted
as described, prosthetic heart valve PHV may be assembled to the
docking station.
[0064] A number of benefits may result from using a two-step
process in which docking station 600 is first implanted within
native valve annulus VA and then prosthetic heart valve PHV is
assembled to docking station 600. For example, when implanted,
prosthetic heart valve PHV, which may take the form of any
traditional prosthetic heart valve or any of the embodiments
disclosed herein, will encounter a predictable environment. That
is, the variability in anatomy from one patient to another will
have less effect on the positioning and functioning of prosthetic
heart valve PHV, because prosthetic heart valve PHV will interact
directly with docking station 600 rather than with the anatomy of
native valve annulus VA.
[0065] FIG. 7A illustrates a stent 700 of a prosthetic heart valve
according to one embodiment of the disclosure. Stent 700 is
collapsible and expandable for use in a prosthetic heart valve
intended to replace the function of the native mitral valve of a
patient. In FIG. 7A, stent 700 is illustrated in its expanded
condition. The remaining components that would be attached to stent
700 to form a prosthetic heart valve, such as leaflets and a cuff,
are omitted from the figures for clarity.
[0066] Stent 700 has inflow end 710 and outflow end 712, and may be
formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 700 may include a plurality of struts 752 that form
cells connected to one another in one or more annular rows around
the stent.
[0067] Stent 700 may be thought of as having at least three main
portions. At inflow end 710 is flared portion 770, which flares
radially outwardly in a direction away from outflow end 712. Flared
portion 770 may include one or more circumferential rows of
relatively small cells 754a. Each cell 754a is formed from a group
of struts 752 that defines a geometric shape having a relatively
small area, in this case generally a diamond shape.
[0068] Stent 700 also includes a substantially cylindrical body 780
that extends from flared portion 770 to outflow end 712 of the
stent. Body 780 may include one or more circumferential rows of
relatively large cells 754b. Each cell 754b is formed from a group
of struts 752 that defines a geometric shape having a relatively
large area, in this case generally a diamond shape. Struts 752
forming larger cells 754b may be thicker and stronger than struts
752 forming smaller cells 754a. Rows of relatively small cells 754a
may be thought of as being a high-density arrangement of cells,
while rows of relatively large cells 754b may be thought as being a
low-density arrangement of cells.
[0069] Stent 700 also includes a portion with anchor members, in
this case hooks 790. Hooks 790 are formed of struts 752 that extend
radially outwardly toward inflow end 710. Hooks 790 may be integral
with stent 700, being formed from the same single piece of starting
material, and may be connected to stent 700 anywhere on body 780.
It should be noted that the term hooks may include other anchoring
structures, for example barbs or clips.
[0070] When being used in a prosthetic heart valve for replacing
the native mitral valve of a patient, stent 700 is crimped to a
collapsed condition and positioned within a catheter or similar
structure of a delivery device. The delivery device may, for
example, be inserted through the apex of the heart (transapical
delivery) or through the femoral artery and passed through the
vasculature to the implant site (transfemoral delivery). Once the
delivery device is near the site of implantation, the sheath or
other member compressing stent 700 may be slowly retracted to
reveal stent 700 and allow it to expand to the expanded condition.
If a transapical method is used with a split sheath, as a proximal
portion of the sheath is retracted proximally, hooks 790 are first
released from the proximal portion of the sheath and expand. The
release of hooks 790 may be performed in left ventricle 124 and
then pushed distally until hooks 790 catch native leaflets 136 and
138. Alternately, the release of hooks 790 may be performed in left
atrium 122, then pulled proximally into left ventricle 124 and then
pushed back to catch native leaflets 136 and 138. The initial
release of hooks 790 may be accomplished with other types of
sheaths, for example with a double proximal sheath with a slot or
other opening in the inner sheath to allow hooks 790 to deploy
first. It should be noted that in the collapsed condition, hooks
790 point toward inflow end 710, rather than toward outflow end
712. In other words, hooks 790 (as well as flared portion 770) are
folded toward left atrium 122 during deployment, such that hooks
790 may gradually expand outwardly as the delivery sheath is slowly
retracted. If, on the other hand, hooks 790 were delivered folded
toward left ventricle 124, once the delivery sheath cleared hooks
790, the hooks would suddenly flip nearly 180 degrees, possibly
causing trauma to native valve annulus VA.
[0071] Once hooks 790 are in place, the distal portion of the split
sheath may be pushed distally to release flared portion 770. As it
is released, flared portion 770 begins to expand on the atrial side
of the native valve annulus VA. Prosthetic heart valve 700 is
illustrated after full release in FIG. 7B. The inclusion of smaller
cells 754a in a high-density arrangement in flared portion 770
allows for relatively greater tissue ingrowth and also facilitates
creating and maintaining the flared shape of flared portion 770,
which provides for better alignment and sealing at inflow end 710
of stent 700.
[0072] With body 780 and hooks 790 in the expanded condition, hooks
790 hook around the native anterior and posterior mitral valve
leaflets, helping secure stent 700 in place. Because body 780 is
generally comprised of larger cells 754b formed of thicker struts
752 instead of smaller cells 754a formed of thinner struts, body
780 is somewhat more rigid and facilitates better anchoring by
hooks 790. This better anchoring may be partly due to the fact that
hooks 790 are connected to body 780, and may also be formed of
relatively thick struts 752 to provide additional strength. In
addition, because hooks 790 point toward inflow end 710 during
delivery and deployment, stent 700 may be resheathed any time prior
to release of flared portion 770 into the expanded condition, for
example by pushing a proximal portion of a split sheath distally
before the distal portion of the split sheath is released. If a
double proximal sheath were used, stent 700 could be resheathed at
any time prior to release of the entire stent into the expanded
condition.
[0073] Referring back to FIG. 7A, stent 700 may include one or more
commissure attachment features ("CAFs") 792 and one or more
retention members 794 as are known in the art. Each CAF 792
provides a site for the prosthetic valve leaflets to be attached to
stent 700. Each retention member 794 provides a feature for
connecting stent 700 to the delivery device, the connection being
maintained until stent 700 is fully released from the delivery
device. It should further be noted that, although hooks 790 are
shown as being formed integrally with stent 700, hooks 790 may be
formed separately of any one or a combination of a variety of
materials, including for example Nitinol, polymers such as
polyvinyl alcohol ("PVA"), and tissues such as bovine or porcine
cardiac tissue.
[0074] FIG. 7C illustrates an alternate embodiment of stent 700' of
a prosthetic heart valve according to another embodiment of the
disclosure. (It should be noted in FIG. 7C that an opaque strip of
material is positioned within stent 700' to more clearly
demonstrate features of the stent. This strip of material forms no
part of stent 700' or the prosthetic valve incorporating the
stent.) Stent 700' has features in common with stent 700. For
example, stent 700' is collapsible and expandable, has inflow end
710' and outflow end 712', and may be formed from biocompatible
materials that are capable of self-expansion. Stent 700' may
include a plurality of struts 752' that form cells connected to one
another in one or more annular rows around the stent. Stent 700'
includes flared portion 770' at inflow end 710'. Flared portion
770' extends radially outwardly in a direction away from outflow
end 712' and may include one or more circumferential rows of cells
754'. Stent 700' may also include a substantially cylindrical body
780' that extends from outflow end 712' toward inflow end 710'.
Body 780' may include one or more circumferential rows of cells
754'. Each cell 754' may be formed from a group of struts 752' that
defines a general diamond shape.
[0075] Stent 700' may also include a portion with anchor members,
such as hooks 790'. Hooks 790' may be formed of struts 752' that
extend radially outwardly toward inflow end 710', and then angle
back such that they extend generally parallel to a longitudinal
axis of stent 700'. Hooks 790' may be integral with stent 700',
being formed from the same single piece of starting material, and
may be connected to stent 700' anywhere on body 780'. Hooks 790'
may be generally similar to hooks 790 of stent 700, with at least
two distinctions. First, as described above, rather than extend at
a generally constant angle radially outward from body 780', hooks
790' extend at a first angle and then angle back such that a free
end of each hook 790' is generally parallel to the longitudinal
axis of stent 700'. As illustrated in FIG. 7D, this configuration
may provide a better clamping action of native valve leaflets 136
and 138. It should be noted that the free end of hooks 790' need
not be exactly parallel to the longitudinal axis and variations
from parallel may exist. Second, the free end of hooks 790' may be
rounded or otherwise curved. Compared to a free end with a sharp
angle, hooks 790' may be less traumatic to the native tissue.
[0076] Flared portion 770' may also vary from flared portion 770 of
stent 700, at least in that flared portion 770' is not connected to
body 780' at the tip of a cell 754'. Rather than being connected to
the portion of body 780' that is closest to inflow end 710', flared
portion 770' is connected to body 780' farther toward outflow end
712'. In the illustrated embodiment, flared portion 770' is
connected to body 780' at a point where two adjacent cells 754' in
the same circumferential row meet. This configuration results in
some overlap in the longitudinal direction of flared portion 770'
and body 780'. When implanted, as illustrated in FIG. 7D, flared
portion 770' makes contact with native valve annulus VA, while the
points on body 780' closest to inflow end 710' extend a distance
into left atrium 122. Because structures including a cuff and valve
assembly (not illustrated in FIGS. 7C-D) would be attached to body
780', retaining the cylindrical geometry of body 780' near the
point of contact between flared portion 770' and native valve
annulus VA may help more evenly distribute the pressures and forces
exerted on stent 700' during normal operation. The delivery and
deployment of a prosthetic heart valve incorporating stent 700' may
be substantially the same as described above in relation to stent
700.
[0077] FIG. 8A illustrates a stent 800 of a prosthetic heart valve
according to another embodiment of the disclosure. Stent 800 is
collapsible and expandable for use in a prosthetic heart valve for
replacing the function of the native mitral valve of a patient. In
FIG. 8A, stent 800 is illustrated in its expanded condition.
[0078] Stent 800 has inflow end 810 and outflow end 812, and may be
formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 800 may include a plurality of struts 852 that form
cells 854 connected to one another in one or more annular rows
around the stent.
[0079] Stent 800 includes a substantially cylindrical body 870 and
two anchor sections. The anchor sections may take the form of a
first circumferential row of hooks 880 and a second circumferential
row of hooks 890. Each hook 880 in the first circumferential row
has a first end attached to inflow end 810 of stent 800 and a free
end extending radially outwardly and toward outflow end 812 of
stent 800 in the expanded condition. (It should be noted in FIG. 8A
that an opaque strip of material is positioned between first
circumferential row of hooks 880 and body 870 to more clearly
demonstrate their relative radial positioning. This strip of
material forms no part of stent 800 or the prosthetic valve
incorporating the stent.) Each hook 890 in the second
circumferential row has a first end attached to body 870 of stent
800 at a spaced distance from inflow end 810 and a free end
extending radially outwardly and toward outflow end 812 in the
expanded condition.
[0080] When being used in a prosthetic heart valve for replacing
the native mitral valve of a patient, stent 800 is crimped to a
collapsed condition and positioned within a catheter or similar
structure of a delivery device. In the collapsed condition, the
free ends of hooks 880 in the first circumferential row and the
free ends of hooks 890 in the second circumferential row all point
toward outflow end 812 of stent 800. If a transfemoral or
transaortic delivery route is used, once at the site of
implantation, a sheath covering stent 800 may be retracted such
that outflow end 812 of stent 800 expands first. As outflow end 812
of stent 800 expands and the sheath is retracted further, hooks 890
in the second circumferential row are released from constraint.
Upon further retraction of the sheath, the remainder of stent 800,
along with hooks 880 in the first circumferential row, are released
from the constraint of the sheath and expand.
[0081] FIG. 8B illustrates stent 800 in its fully expanded state
within native mitral valve annuls VA. In particular, hooks 880 in
the first circumferential row are positioned on, and in contact
with, the atrial side of native valve annulus VA. Hooks 890 in the
second circumferential row are positioned on, and in contact with,
the ventricular side of native valve annulus VA. This positioning
facilitates anchoring of stent 800 in native valve annulus VA, and
helps to prevent PV leak.
[0082] Because the free ends of hooks 880 and 890 are all pointed
toward outflow end 812 during deployment, stent 800 may be
resheathed any time prior to release of the entire stent into the
expanded condition. Similarly, because of this orientation of hooks
880 and 890 during deployment, the transition of hooks 880 and 890
from the collapsed condition to the expanded condition is
relatively gradual, decreasing the likelihood of trauma to native
valve annulus VA during release of stent 800 from the sheath. It
should be understood that a similar result may be achieved with a
transapical delivery route if a sheath with a distal pull-off is
used. Further, other routes not specifically mentioned herein, such
through the inferior vena cava, may be used with an appropriate
sheath to allow the desired order of release and resheathing
capabilities, as would be understood by one of ordinary skill in
the art.
[0083] Referring back to FIG. 8A, stent 800 may include one or more
CAFs 892 and one or more retention members 894 as are known in the
art. It should be noted that retention members 894 are on inflow
end 810 in this case because inflow end 810 is intended to be
released at the end of deployment. This is in contrast to retention
members 794 of stent 700 in FIG. 7A, which are on outflow end 712
because outflow end 712 of stent 700 is intended to be released at
the end of deployment.
[0084] FIG. 9 illustrates stent 900 of a prosthetic heart valve
according to a further embodiment of the disclosure. Stent 900 is
collapsible and expandable for use in a prosthetic heart valve
intended to replace the function of the native mitral valve of a
patient. In FIG. 9, stent 900 is illustrated as if it were cut
longitudinally and laid out in a flat, expanded condition.
[0085] Stent 900 has inflow end 910 and outflow end 912 and may be
formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 900 may include a plurality of struts 952 that form
cells 954 connected to one another in one or more annular rows
around the stent.
[0086] Stent 900 includes a substantially cylindrical body 970 and
two anchor sections. The anchor sections may take the form of a
first circumferential row of hooks 980 and a second circumferential
row of hooks 990. Each hook 980 in the first circumferential row
has a first end attached to inflow end 910 of stent 900 and a free
end extending radially outwardly and toward outflow end 912 of
stent 900 when in the expanded condition. Each hook 990 in the
second circumferential row has a first end attached to body 970 of
stent 900 at a spaced distance from inflow end 910 and a free end
extending radially outwardly and toward inflow end 910 of stent 900
when in the expanded condition. It should be noted that, when in
the expanded condition, hooks 980 and 990 may extend generally
perpendicular to stent body 970 or at an oblique angle towards
either inflow end 910 or outflow end 912. It should also be noted
that each circumferential row of hooks 980 or 990 need not be
continuous. For example, groups of one, two, or more hooks 990 may
be provided to anchor stent 900 to native anterior and posterior
mitral valve leaflets, with a number of cells 954 without hooks 990
being positioned between the groups.
[0087] When used in a prosthetic heart valve intended to replace
the native mitral valve of a patient, stent 900 is crimped to a
collapsed condition and positioned within a catheter or similar
structure of a delivery device. In the collapsed condition, the
free ends of hooks 980 in the first circumferential row and the
free ends of hooks 990 in the second circumferential row all point
toward the center of stent 900. This may be particularly useful
when a split sheath is being used to deploy stent 900.
[0088] Generally, a split sheath refers to a sheath that is
configured to house stent 900 in a collapsed condition and a
portion of the sheath housing the stent may move distally with
respect to the stent while the remainder of the sheath housing the
stent may remain stationary or may independently move proximally
with respect to the stent. With a split sheath inflow end 910 may
be exposed before or after outflow end 912. In other words, distal
movement of one portion of the sheath housing will expose inflow
end 910, while proximal movement of the remainder of the sheath
housing will expose outflow end 912. Although hooks 980 and 990 may
be deployed in any desired order, it may be preferable to first
deploy second circumferential row of hooks 990 in left ventricle
124 and then push stent 900 such that hooks 990 engage native valve
leaflets 136 and 138. Once engaged, and first circumferential row
of hooks 980 may be deployed in left atrium 122 while keeping a
portion of the distal delivery sheath covering inflow end 910. Once
proper positioning is verified, the distal sheath may be pushed
beyond inflow end 910 and the proximal sheath may be pulled off the
outflow end 912 to fully release stent 900. When in the fully
expanded condition, stent 900 may be anchored to the native mitral
valve in a manner similar to that illustrated in FIG. 8B. However,
unlike other embodiments described herein, the configurations of
hooks 980 and 990 allow the entire stent 900 to be resheathed prior
to the full release of the stent when a split sheath device is used
for deployment.
[0089] FIG. 10 illustrates a stent 1000 of a prosthetic heart valve
according to a further embodiment of the disclosure. Stent 1000 is
collapsible and expandable for use in a prosthetic heart valve for
replacing the function of the native mitral valve of a patient. In
FIG. 10, stent 1000 is illustrated in the expanded condition.
[0090] Stent 1000 has inflow end 1010 and outflow end 1012 and may
be formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 1000 may include a plurality of struts 1052 that
form cells 1054 connected to one another in one or more annular
rows around the stent.
[0091] Stent 1000 includes a substantially cylindrical body 1070
and two anchor sections. The anchor sections may take the form of a
first circumferential row of hooks 1080 and a second
circumferential row of hooks 1090. Each hook 1080 in the first
circumferential row has a first end attached to inflow end 1010 of
stent 1000 and a free end extending radially outwardly. Each hook
1090 in the second circumferential row has a first end attached to
outflow end 1012 of stent 1000 and a free end extending radially
outwardly. In the expanded condition, hooks 1080 and 1090 may
extend substantially perpendicularly to the central axis of body
1070 or, for each circumferential row, the hooks in that
circumferential row may extend at an angle towards the hooks in the
other circumferential row. Each hook 1080 may be a part of a single
cell 1054 that is also part of body 1070. Similarly, each hook 1090
may be part of a single cell 1054 that is also part of body 1070.
The first circumferential row of hooks 1080 may extend continuously
around the perimeter of inflow end 1010. In other words, each cell
1054 at inflow end 1010 may form a hook 1080. However, it should be
understood that hooks 1080 need not extend continuously around the
perimeter of inflow end 1010 and cells 1054 not forming a hook may
be interposed between cells that do form hooks. The second
circumferential row of hooks 1090 is preferably not continuous. In
other words, at least some cells 1054 at outflow end 1012
preferably do not from a hook 1090. For example, cells 1054
terminating in a CAF 1094 preferably do not form a hook 1090,
otherwise the ability to attach a prosthetic valve to stent 1000
could be hindered.
[0092] When used in a prosthetic heart valve to replace the native
mitral valve of a patient, stent 1000 is crimped to a collapsed
condition and positioned within a catheter or similar structure of
a delivery device. In the collapsed condition, the free ends of
hooks 1080 in the first circumferential row point away from outflow
end 1012 and the free ends of hooks 1090 in the second
circumferential row point away from inflow end 1010.
[0093] Depending on the particular mode of delivery and sheath used
to deploy stent 1000, stent 1000 may be only partially
resheathable. In other words, if the hooks in only one
circumferential row have been deployed from the delivery device,
stent 1000 may be resheathed to reposition its associated
prosthetic valve. If, on the other hand, the hooks in both
circumferential rows have been deployed from the delivery device,
stent 1000 may no longer be resheathed even if retention members
1094 are still connected to the delivery device. Despite being only
partially resheathable, the configuration of stent 1000 may provide
a number of benefits. For example, stent 1000 generally has a less
complex structure than, for example, stents 700, 800, and 900,
which may result in simplified manufacturing. Also, at least partly
because hooks 1080 and 1090 are portions of cells 1054 of body
1070, all cells 1000 of stent 1050 may be arranged in a
high-density format. The high-density format may provide, for
example, a greater surface area of material to interact with the
native anatomy as well as for supporting a cuff, valves, and/or
sealing materials attached thereto. In addition, when in the
crimped condition, there is no overlap between either row of hooks
and cylindrical body 1070, permitting a smaller crimp profile to be
obtained. Similarly to stents 700, 800, and 900, once stent 1000 is
properly positioned in native valve annulus VA, hooks 1080 and 1090
may function to both anchor stent 1000 in place and to help seal
against PV leak.
[0094] FIG. 11 illustrates a prosthetic heart valve 1100 according
to another embodiment of the disclosure. Prosthetic heart valve
1100 is collapsible and expandable and designed to replace the
function of the native mitral valve of a patient. In FIG. 11,
prosthetic heart valve 1100 is illustrated in the expanded
condition.
[0095] Prosthetic heart valve 1100 may include wire-form stent
1150, which may be formed from biocompatible materials that are
capable of self-expansion, such as, for example, shape memory
alloys including Nitinol. Unlike other embodiments described
herein, stent 1150 may be formed from a single wire 1152 shaped as
desired, as opposed to, for example, a single tube laser cut to a
desired shape. In the illustrated embodiment, stent 1150 includes
two anchor sections. In particular, the anchor sections may include
a first series of hooks 1180 and a second series of hooks 1190.
Each hook 1180 in the first series may extend radially outward from
inflow end 1110 of stent 1150. Each hook 1190 in the second series
may extend radially outward from outflow end 1112 of stent 1150. A
free end of each hook 1190 may be bent back toward inflow end
1110.
[0096] Prosthetic heart valve 1100 may include a cuff 1164 attached
to stent 1150. Cuff 1164 may include a first generally flat portion
1164a that spans across and is attached to first series of hooks
1180. Preferably, hooks 1180 extend substantially in a continuous
pattern around the circumference of prosthetic heart valve 1100 to
provide adequate support for first cuff portion 1164a. When
prosthetic heart valve 1100 is implanted, first cuff portion 1164a
is positioned on the atrial side of the native valve annulus and
may act as a sealing member similar to sealing members 480 and 580
of prosthetic heart valves 400 and 500, respectively. Cuff 1164 may
include a second portion 1164b projecting from flat portion 1164a
in the form of an annular wall surrounding an opening generally in
the center of the flat portion. Second portion 1164b provides
structure for the attachment of prosthetic leaflets to prosthetic
heart valve 1100. When prosthetic heart valve 1100 is implanted,
second series of hooks 1190 may be positioned on the ventricular
side of the native mitral valve annulus, and may hook around the
native mitral valve leaflets to provide anchoring for prosthetic
heart valve 1100. With this configuration, two groups of hooks 1190
corresponding to the positions of native mitral valve leaflets may
be sufficient for anchoring, without needing hooks 1190 to extend
around the entire circumference of stent 1150.
[0097] While prosthetic leaflets may be attached to cuff 1164 and
stent 1150 to form a fully functioning prosthetic heart valve, cuff
1164 and stent 1150 may be used in combination as a docking station
in a two-step delivery system, similar to docking station 600
described above. If used as a docking station, cuff 1164 and stent
1150 may be implanted in the native valve annulus first, followed
by the implantation of a traditional prosthetic heart valve or any
prosthetic heart valve described herein.
[0098] FIG. 12 is a side view of prosthetic heart valve 1200
according to a further embodiment of the disclosure. Prosthetic
heart valve 1200 is a collapsible prosthetic heart valve designed
to replace the function of the native mitral valve of a patient.
Prosthetic valve 1200 may be substantially cylindrical, with inflow
end 1210 and outflow end 1212. When used to replace native mitral
valve 130, prosthetic valve 1200 may have a low profile so as not
to interfere with atrial function in the native valve annulus.
[0099] Prosthetic heart valve 1200 may include stent 1250, which
may be formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 1250 may include a plurality of struts 1252 that
form cells 1254 connected to one another in one or more annular
rows around the stent.
[0100] Prosthetic heart valve 1200 may also include a valve
assembly similar to that described in connection with FIGS. 3A-B.
The prosthetic leaflets of the valve assembly replace the function
of native mitral valve leaflets 136 and 138. That is, the leaflets
coapt with one another to function as a one-way valve. The
prosthetic leaflets may be attached to stent 1250 at one or more
CAFs 1294. Each CAF 1294 may be integral with stent 1250, for
example by laser cutting the entire structure from a tube of
material.
[0101] For prosthetic mitral valves, the stents generally include
CAFs that extend in the outflow direction and which are connected
to a cell at the outflow end of the stent. In other words, CAFs are
generally positioned at an end of the stent. Due to this
positioning, and due to the fact that the prosthetic leaflets are
attached to the CAFs and are subjected to forces, for example from
restricting blood flow in the retrograde direction, the CAFs are
prone to deflect inwardly at times during normal operation. This is
particularly true when the mitral valve is closed and the pressure
in the left ventricle is greater than the pressure in the left
atrium.
[0102] As illustrated in FIG. 12, CAF 1294 is embedded within a
cell 1254 of stent 1250, rather than being positioned beyond
outflow end 1212. In other words, CAF 1294 is positioned between
inflow end 1210 and outflow end 1212. CAF 1294 has a first end
attached to struts 1252 and a second free end pointing toward
inflow end 1210. This configuration may reduce the torque
experienced by CAF 1294 due to the forces acting on the prosthetic
leaflets attached to CAF 1294, thereby reducing the deflection of
CAF 1294 during normal operation. This, in turn, may result in
better coaptation between the prosthetic leaflets and less
deterioration of the valve.
[0103] As illustrated in FIG. 12, CAF 1294 is embedded within a
cell 1254 of stent 1250, rather than being positioned beyond
outflow end 1212. In other words, CAF 1294 is positioned between
inflow end 1210 and outflow end 1212. CAF 1294 has a first end
attached to struts 1252 and a second free end pointing toward
inflow end 1210. This configuration may reduce the torque
experienced by CAF 1294 due to the forces acting on the prosthetic
leaflets attached to CAF 1294, thereby reducing the deflection of
CAF 1294 during normal operation. This, in turn, may result in
better coaptation between the prosthetic leaflets and less
deterioration of the valve.
[0104] FIG. 13 illustrates a stent 1300 of a prosthetic heart valve
according to still another embodiment of the disclosure. Stent 1300
is collapsible and expandable for use in a prosthetic heart valve
intended to replace the function of the native mitral valve of a
patient. In FIG. 13, stent 1300 is illustrated in its expanded
condition.
[0105] Stent 1300 has inflow end 1310 and outflow end 1312, and may
be formed from biocompatible materials that are capable of
self-expansion, such as, for example, shape memory alloys including
Nitinol. Stent 1300 may include a plurality of struts 1352 that
form cells 1354 connected to one another in one or more annular
rows around stent 1300.
[0106] Stent 1300 may be thought of as having an atrial portion
1370 and a ventricular portion 1380. When implanted in native valve
annulus VA, atrial portion 1370 of stent 1300 is positioned on the
atrial side of native valve annulus VA, while ventricular portion
1380 of stent 1300 is positioned on the ventricular side of native
valve annulus VA. Atrial portion 1370 of stent 1300 has a generally
bulbous shape and is configured to protrude farther into left
atrium 122 than ventricular portion 1380 protrudes into left
ventricle 124. The bulbous shape of atrial portion 1370 provides
anchoring of stent 1300, helping to resist the migration of the
stent into left ventricle 124. The bulbous shape of atrial portion
1370 and the extent of anchoring in left atrium 122 reduce the
radial forced needed at native valve annulus VA to keep stent 1300
in place. As a result, ventricular portion 1380 need only extend
minimally into left ventricle 124, which may reduce interference
with chordae tendineae 134. For example, as illustrated, less than
a full row of cells 1354 is configured to be positioned in left
ventricle 124 when stent 1300 is implanted in native valve annulus
VA.
[0107] Various modifications may be made to the embodiments
disclosed herein without departing from the scope of the
disclosure. For example, although stents and prosthetic heart
valves are generally described for replacement of the mitral other
bicuspid valves, variations may be made to these devices to replace
tricuspid valves. Thus, the prosthetic valves may be provided with
three leaflets, or more or less leaflets as desired. Similarly,
although generally described as self-expanding prosthetic heart
valves or stents, the principles described herein are also
applicable to prosthetic valves that are not self-expanding, such
as balloon expandable prosthetic valves.
[0108] According to one embodiment of the disclosure, a prosthetic
heart valve comprises: a stent having an inflow end, an outflow
end, a center portion between the inflow end and the outflow end, a
collapsed condition, and an expanded condition; a collapsible and
expandable valve assembly disposed within the stent and having a
plurality of leaflets; a first annular sealing member coupled to
the inflow end; and a second annular sealing member coupled to the
outflow end; and/or [0109] the first and second sealing members
each have a diameter greater than a diameter of the stent when the
stent is in the expanded condition; and/or [0110] the stent is
substantially cylindrical in the expanded condition; and/or [0111]
the first sealing member has a substantially planar configuration
when the stent is in the expanded condition; and/or [0112] the
inflow end and the outflow end of the stent each has a diameter
greater than a diameter of the center portion of the stent when the
stent is in the expanded condition; and/or [0113] the first sealing
member is substantially nonplanar when the stent is in the expanded
condition; and/or [0114] an outer perimeter of the first sealing
member is closer to the outflow end than an inner perimeter of the
first sealing member when the stent is in the expanded
condition.
[0115] According to another embodiment of the disclosure, a stent
having an expanded condition and a collapsed condition comprises: a
substantially cylindrical body having a first end and a second end;
a flared portion coupled to the first end of the body and extending
radially outwardly from the body and away from the second end of
the body when the stent is in the expanded condition; and a
plurality of anchor members each having a first end coupled to the
body and a second free end extending radially outwardly from the
body and toward the first end of the body when the stent is in the
expanded condition, wherein the flared portion and the second free
ends of the anchor members are configured to extend away from the
second end of the body when the stent is in the collapsed
condition; and/or [0116] the flared portion and the body are each
formed of a plurality of struts that form cells having an area, the
area of each cell of the body being greater than the area of each
cell of the flared portion when the stent is in the expanded
condition; and/or [0117] the flared portion and the body are each
formed of a plurality of struts having a thickness, the thickness
of the struts forming the flared portion being less than the
thickness of the struts forming the body.
[0118] According to a further embodiment of the disclosure a stent
having an expanded condition and a collapsed condition comprises: a
substantially cylindrical center body having a first end and a
second end; a first plurality of anchor members each having a first
end coupled to the first end of the body and a second free end
extending radially outwardly from the body and toward the second
end of the body when the stent is in the expanded condition; and a
second plurality of anchor members each having a first end coupled
to the body and a second free end extending radially outwardly from
the body and toward the second end of the body when the stent is in
the expanded condition, wherein the first and second plurality of
anchor members are configured to extend toward the second end of
the body when the stent is in the collapsed condition.
[0119] According to still another embodiment of the disclosure, a
stent having an expanded condition and a collapsed condition
comprises: a substantially cylindrical center body having a first
end and a second end; a first plurality of anchor members each
having a first end coupled to the body and a second free end
extending radially outwardly from the body and toward the first end
of the body when the stent is in the expanded condition; and a
second plurality of anchor members each having a first end coupled
to the first end of the body and a second free end extending
radially outwardly from the body and toward the second end of the
body when the stent is in the expanded condition, wherein the first
plurality of anchor members extend toward the first end of the body
and the second plurality of anchor members extend toward the second
end of the body when the stent is in the collapsed condition;
and/or [0120] the second plurality of anchor members includes a
first group of anchor members and a second group of anchor members,
the first group being configured to engage a native posterior
mitral valve leaflet and the second group being configured to
engage a native anterior mitral valve leaflet when the stent is
implanted in a native mitral valve annulus of a patient.
[0121] According to yet another embodiment of the disclosure, a
stent having an expanded condition and a collapsed condition
comprises: a substantially cylindrical center body having a first
end, a second end, and a longitudinal axis extending between the
first end and the second end; a first plurality of anchor members
each having a first end coupled to the body and a second free end
extending radially outwardly from the body and substantially
perpendicular to the longitudinal axis of the body when the stent
is in the expanded condition; and a second plurality of anchor
members each having a first end coupled to the body and a second
free end extending radially outwardly from the body and
substantially perpendicular to the longitudinal axis of the body
when the stent is in the expanded condition, wherein the first
plurality of anchor members extend away from the second end of the
body and the second plurality of anchor members extend away from
the first end of the body when the stent is in the collapsed
condition; and/or [0122] a plurality of struts forming a first
circumferential row of cells and a second circumferential row of
cells, wherein each of the first plurality of anchor members is at
least partially formed from one of the cells in the first
circumferential row and each of the second plurality of anchor
members is at least partially formed from one of the cells in the
second circumferential row.
[0123] According to yet a further embodiment of the disclosure, a
prosthetic heart valve comprises: a stent having an inflow end, an
outflow end, a collapsed condition, and an expanded condition, the
stent being formed from wire and having a first series of hooks and
a second series of hooks; and a cuff coupled to the stent, wherein,
when the stent is in the expanded condition, each hook of the first
series extends radially outwardly from the stent at the inflow end
and each hook of the second series includes a first portion that
extends radially outwardly from the stent at the outflow end and a
second portion that extends toward the inflow end; and/or [0124]
the cuff has a first substantially flat portion that spans across
and is coupled to the first series of hooks.
[0125] According to an even further embodiment of the disclosure, a
prosthetic heart valve comprises: a stent having an inflow end, an
outflow end, a collapsed condition, and an expanded condition, the
stent being formed of a plurality of struts; a collapsible and
expandable valve assembly disposed within the stent and having a
plurality of leaflets; and a commissure attachment feature attached
to at least one of the plurality of struts and positioned between
the inflow end and the outflow end when the stent is in the
expanded condition; and/or [0126] the commissure attachment feature
has a first end attached to at least one of the plurality of struts
and a second free end extending toward the inflow end when the
stent is in the expanded condition.
[0127] It will be appreciated that the various dependent claims and
the features set forth therein can be combined in different ways
than presented in the initial claims. It will also be appreciated
that the features described in connection with individual
embodiments may be shared with others of the described
embodiments.
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