U.S. patent application number 12/393010 was filed with the patent office on 2010-08-26 for mitral valve replacement with atrial anchoring.
This patent application is currently assigned to Edwards Lifesciences. Invention is credited to Mark Chau, Phillip P. Corso, JR., Kevin Golemo, Son V. Nguyen, Jane M. Olin, Michael Popp, Seung Yi.
Application Number | 20100217382 12/393010 |
Document ID | / |
Family ID | 42631661 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100217382 |
Kind Code |
A1 |
Chau; Mark ; et al. |
August 26, 2010 |
MITRAL VALVE REPLACEMENT WITH ATRIAL ANCHORING
Abstract
A prosthetic mitral valve assembly and method of inserting the
same is disclosed. In certain disclosed embodiments, the prosthetic
mitral valve assembly includes a stent and valve combination. The
stent is designed so that the anchoring portion is positioned above
the annulus of the mitral valve and in the left atrium. The stent
is radially expandable so that it can expand into position against
the walls of the left atrium and accommodate a wide range of
anatomies. Contact between the stent and the native tissue in the
left atrium reduces paravalvular leakage and prevents migration of
the stent once in place.
Inventors: |
Chau; Mark; (Aliso Viejo,
CA) ; Yi; Seung; (Aliso Viejo, CA) ; Corso,
JR.; Phillip P.; (Irvine, CA) ; Popp; Michael;
(Lake Forest, CA) ; Golemo; Kevin; (Mission Viejo,
CA) ; Olin; Jane M.; (Irvine, CA) ; Nguyen;
Son V.; (Irvine, CA) |
Correspondence
Address: |
EDWARDS LIFESCIENCES CORPORATION
LEGAL DEPARTMENT, ONE EDWARDS WAY
IRVINE
CA
92614
US
|
Assignee: |
Edwards Lifesciences
|
Family ID: |
42631661 |
Appl. No.: |
12/393010 |
Filed: |
February 25, 2009 |
Current U.S.
Class: |
623/1.26 ;
623/2.12 |
Current CPC
Class: |
A61F 2220/0016 20130101;
A61F 2/2457 20130101; A61F 2230/0054 20130101; A61F 2250/0039
20130101; A61F 2220/0075 20130101; A61F 2/2436 20130101; A61F
2/2418 20130101; A61F 2230/0078 20130101 |
Class at
Publication: |
623/1.26 ;
623/2.12 |
International
Class: |
A61F 2/06 20060101
A61F002/06; A61F 2/24 20060101 A61F002/24 |
Claims
1. A prosthetic mitral valve assembly for implantation in a heart
having a native mitral valve positioned between a left atrium and
left ventricle, comprising: a radially-expandable stent sized so
that an anchoring portion of the stent is implantable in the left
atrium above an annulus of the native mitral valve with a pressure
or friction fit against the atrium walls; and a valve portion
coupled to the stent.
2. The prosthetic mitral valve assembly of claim 1, wherein the
valve portion is designed to work in series with the native mitral
valve.
3. The prosthetic mitral valve assembly of claim 1, wherein the
anchoring portion is an upper portion of the stent and the stent
further includes a lower portion for extending into the native
mitral valve, the valve portion being mounted in the lower portion
of the stent so that the portion of the stent for anchoring the
valve is independent of the portion of the stent for anchoring the
mitral valve assembly in the heart.
4. The prosthetic mitral valve assembly of claim 1, wherein the
stent is made of shape memory material formed in a lattice
pattern.
5. The prosthetic mitral valve assembly of claim 1, wherein the
stent includes anchoring arms designed to extend from the stent for
contacting an upper portion of the atrium.
6. The prosthetic mitral valve assembly of claim 5, wherein each
anchoring arm has a first end coupled to the stent and a second end
designed to contact an upper portion of the atrium, wherein the
second ends of the anchoring arms are coupled together.
7. The prosthetic mitral valve assembly of claim 5, wherein the
anchoring arms are made of a flexible metal or polymer.
8. The prosthetic mitral valve assembly of claim 1, wherein the
stent includes at least one anchoring arm designed to extend from
the stent, the anchoring arm having a distal end for mounting in a
pulmonary vein of a patient.
9. The prosthetic mitral valve assembly of claim 1, wherein the
stent has an upper domed-shaped portion designed to contact an
upper portion of the atrium.
10. The prosthetic mitral valve assembly of claim 1, wherein the
valve portion further includes prosthetic leaflets and further
including tension members coupled to the prosthetic leaflets for
preventing the prosthetic leaflets from everting and reducing
stresses induced by ventricular contraction.
11. The prosthetic mitral valve assembly of claim 10, wherein the
tension members are coupled to the prosthetic leaflets at a first
end of the tension members and coupled at an opposite end to the
stent or to a patient's heart.
12. The prosthetic mitral valve assembly of claim 1, further
including a tether coupled to the stent on one end thereof, the
tether being configured to couple the stent to a portion of the
heart remote from the stent.
13. The prosthetic mitral valve assembly of claim 1, further
including prongs extending outwardly from the stent that are
integral with the stent or separate barbs coupled to the stent.
14. A prosthetic mitral valve assembly, comprising: a
radially-expandable stent having an upper portion sized so that an
anchoring portion of the stent is implantable in a left atrium
above an annulus of a native mitral valve with a pressure or
friction fit and a lower portion for extending into the native
mitral valve, the upper portion of the stent having a circumference
that is greater than a circumference of the lower portion; and a
valve portion coupled within the lower portion to the stent.
15. The prosthetic mitral valve assembly of claim 14, wherein the
stent is made of shape memory material formed in a lattice
pattern.
16. The prosthetic mitral valve assembly of claim 14, wherein the
stent includes anchoring arms designed to extend from the stent for
contacting an upper portion of the atrium.
17. The prosthetic mitral valve assembly of claim 16, wherein each
anchoring arm has a first end coupled to the stent and a second end
designed to contact an upper portion of the atrium, wherein the
second ends of the anchoring arms are coupled together.
18. The prosthetic mitral valve assembly of claim 16, wherein the
anchoring arms are made of a flexible metal or polymer.
19. The prosthetic mitral valve assembly of claim 14, wherein the
stent includes at least one anchoring arm designed to extend from
the stent, the anchoring arm having a distal end for mounting in a
pulmonary vein of a patient.
20. The prosthetic mitral valve assembly of claim 14, wherein the
upper portion of the stent has a domed-shaped end designed to
contact an upper portion of the atrium.
21. The prosthetic mitral valve assembly of claim 14, wherein the
prosthetic mitral valve assembly is adapted to expand into contact
with the native mitral valve tissue to create the pressure or
friction fit and secure the mitral valve assembly in a fixed
position in the heart.
22. The prosthetic mitral valve assembly of claim 14, wherein the
lower portion is tapered and is designed to only partially extend
into the native mitral valve.
23. The prosthetic mitral valve assembly of claim 14, wherein the
lower portion is designed to fully extend into the native mitral
valve.
24. The prosthetic mitral valve assembly of claim 14, further
including prongs extending outwardly from the stent that are
integral with the stent or separate barbs coupled to the stent.
25. A method of implanting a prosthetic mitral heart valve,
comprising: inserting a prosthetic mitral valve assembly in a
collapsed state into a heart using a delivery catheter; expanding
the prosthetic mitral valve assembly; and positioning the
prosthetic mitral valve assembly so that an anchoring portion of
the stent is implantable in the left atrium above an annulus of the
native mitral valve with a pressure fit.
26. The method of claim 25, further including positioning the
prosthetic mitral valve assembly so that a first portion of the
mitral valve assembly is in contact with a roof of a left atrium or
is in contact with pulmonary veins in order to provide a downward
force on a second portion of the mitral valve assembly and prevent
the mitral valve assembly from upward migration.
27. The method of claim 25, wherein the mitral valve assembly
includes a stent and a valve coupled to the stent.
28. The method of claim 25, wherein positioning the prosthetic
mitral valve assembly includes wedging the mitral valve assembly
into place so that an upper end thereof is prevented from moving
upward through contact with a roof of the left atrium or through
contact with the pulmonary veins and a lower end thereof is
prevented from moving downward by leaflets of the native mitral
valve.
Description
FIELD
[0001] The present disclosure concerns a prosthetic mitral heart
valve and a method for implanting such a heart valve.
BACKGROUND
[0002] Prosthetic cardiac valves have been used for many years to
treat cardiac valvular disorders. The native heart valves (such as
the aortic, pulmonary, tricuspid and mitral valves) serve critical
functions in assuring the forward flow of an adequate supply of
blood through the cardiovascular system. These heart valves can be
rendered less effective by congenital, inflammatory, infectious
conditions or disease. Such damage to the valves can result in
serious cardiovascular compromise or death. For many years the
definitive treatment for such disorders was the surgical repair or
replacement of the valve during open heart surgery, but such
surgeries are prone to many complications. More recently a
transvascular technique has been developed for introducing and
implanting a prosthetic heart valve using a flexible catheter in a
manner that is less invasive than open heart surgery.
[0003] In this technique, a prosthetic valve is mounted in a
crimped state on the end portion of a flexible catheter and
advanced through a blood vessel of the patient until the valve
reaches the implantation site. The valve at the catheter tip is
then expanded to its functional size at the site of the defective
native valve such as by inflating a balloon on which the valve is
mounted.
[0004] Another known technique for implanting a prosthetic aortic
valve is a transapical approach where a small incision is made in
the chest wall of a patient and the catheter is advanced through
the apex (i.e., bottom tip) of the heart. Transapical techniques
are disclosed in U.S. Patent Application Publication No.
20070112422, which is hereby incorporated by reference. Like the
transvascular approach, the transapical approach includes a balloon
catheter having a steering mechanism for delivering a
balloon-expandable prosthetic heart valve through an introducer to
the aortic annulus. The balloon catheter includes a deflecting
segment just proximal to the distal balloon to facilitate
positioning of the prosthetic heart valve in the proper orientation
within the aortic annulus.
[0005] The above techniques and others have provided numerous
options for high-risk patients with aortic valve stenosis to avoid
the consequences of open heart surgery and cardiopulmonary bypass.
While procedures for the aortic valve are well-developed, such
procedures are not necessarily applicable to the mitral valve.
[0006] Mitral valve repair has increased in popularity due to its
high success rates, and clinical improvements noted after repair.
Unfortunately, a significant percentage of patients still receive
mitral valve replacement due to stenosis or anatomical limitations.
There are a number of technologies aimed at making mitral repair a
less invasive procedure. These technologies range from iterations
of the Alfieri stitch procedure to coronary sinus-based
modifications of mitral anatomy to subvalvular placations or
ventricular remodeling devices, which would incidently correct
mitral regurgitation.
[0007] However, for mitral valve replacement, few less-invasive
options are available. There are approximately 60,000 mitral valve
replacements (MVR) each year and it is estimated that another
60,000 patients should receive a MVR due to increased risk of
operation and age. The large majority of these replacements are
accomplished through open-heart surgery. One potential option for a
less invasive mitral valve replacement is disclosed in U.S. Patent
Application 2007/0016286 to Herrmann. However, the stent disclosed
in that application has a claw structure for attaching the
prosthetic valve to the heart. Such a claw structure could have
stability issues and limit consistent placement of a transcatheter
mitral replacement valve.
[0008] Accordingly, further options are needed for less-invasive
mitral valve replacement.
SUMMARY
[0009] A prosthetic mitral valve assembly and method of inserting
the same is disclosed.
[0010] In certain disclosed embodiments, the prosthetic mitral
valve assembly includes a stent and valve combination. The stent is
designed so that the anchoring portion is positioned above the
annulus of the mitral valve and in the left atrium. The stent is
radially expandable and can press against the walls of the left
atrium with a pressure or friction fit to accommodate a wide range
of anatomies.
[0011] In one embodiment, the entire prosthetic mitral valve
assembly is positioned above the native annulus so that the native
mitral valve leaflets and chordae are preserved. As a result, the
prosthetic mitral valve and the native mitral valve function in
series.
[0012] In another embodiment, a majority of the prosthetic mitral
valve assembly is implantable in the left atrium. However, a lower
portion of the mitral valve assembly extends into the native mitral
valve rendering the native mitral valve incompetent. Contact
between the stent and the native tissue in the left atrium reduces
paravalvular leakage and prevents migration of the stent once in
place.
[0013] In another embodiment, a majority of the prosthetic mitral
valve assembly is implantable in the left atrium. A lower tapered
portion partially extends into the native mitral valve but does not
extend into the left ventricle in order to ensure that the chordae
tendineae are not contacted by portions of the stent. This
embodiment can improve cardiac performance while preserving the
function of the chordae tendineae.
[0014] In yet another embodiment, the mitral valve assembly
includes additional anchoring with one or more anchoring arms that
contact an upper portion of the atrium or the pulmonary veins. The
anchoring arms utilize the natural anatomy of the patient's heart
in order to resist against upward migration of the assembly. Other
embodiments also use the upper portion of the atrium or the
pulmonary veins without using anchoring arms.
[0015] The foregoing and other objects, features, and advantages of
the invention will become more apparent from the following detailed
description, which proceeds with reference to the accompanying
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of an embodiment of a mitral
valve assembly that can be inserted into the native mitral valve,
but that is anchored above a native annulus.
[0017] FIG. 2 is a perspective view of another embodiment of a
mitral valve assembly that can work in series with the native
mitral valve.
[0018] FIG. 3 is a perspective view of another embodiment of a
mitral valve assembly having outwardly extending prongs for
anchoring the assembly.
[0019] FIG. 4 is a perspective view of another embodiment of a
mitral valve assembly that can extend partially into the native
mitral valve.
[0020] FIG. 5 is a cross-sectional view of a heart with the mitral
valve assembly of FIG. 2 mounted in the left atrium.
[0021] FIG. 6 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with the mitral valve assembly extending to a roof of the
atrium.
[0022] FIG. 7 is a cross-sectional view of a heart with another
embodiment of the mitral valve assembly mounted in the left atrium
and having at least one anchoring arm extending to a roof of the
atrium.
[0023] FIG. 8 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending into at least one
pulmonary vein.
[0024] FIG. 9 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending to a roof of the
atrium.
[0025] FIG. 10 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending into at least one
pulmonary vein.
[0026] FIG. 11 is a cross-sectional view of a heart having the
mitral valve assembly of FIG. 1 mounted in the left atrium with a
lower portion of the mitral valve assembly positioned in the native
mitral valve.
[0027] FIG. 12 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with the mitral valve assembly extending to the roof of the atrium
and with a lower portion of the mitral valve assembly positioned in
the native mitral valve.
[0028] FIG. 13 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending to a roof of the atrium
and with a lower portion of the mitral valve assembly positioned in
the native mitral valve.
[0029] FIG. 14 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending into pulmonary veins and
with a lower portion of the mitral valve assembly positioned in the
native mitral valve.
[0030] FIG. 15 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending to a roof of the atrium
and with a lower portion of the mitral valve assembly positioned in
the native mitral valve.
[0031] FIG. 16 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending into pulmonary veins and
with a lower portion of the mitral valve assembly positioned in the
native mitral valve.
[0032] FIG. 17 is a cross-sectional view of a heart having the
mitral valve assembly of FIG. 4 mounted in the left atrium.
[0033] FIG. 18 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with the mitral valve assembly extending to a roof of the
atrium.
[0034] FIG. 19 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending to a roof of the atrium
and with a lower portion of the mitral valve assembly partially
extending into the native mitral valve.
[0035] FIG. 20 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending into pulmonary veins and
with a lower portion of the mitral valve assembly partially
extending into the native mitral valve.
[0036] FIG. 21 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending to a roof of the atrium
and with a lower portion of the mitral valve assembly partially
extending into the native mitral valve.
[0037] FIG. 22 is a cross-sectional view of a heart having another
embodiment of the mitral valve assembly mounted in the left atrium
with at least one anchoring arm extending into pulmonary veins and
with a lower portion of the mitral valve assembly partially
extending into the native mitral valve.
[0038] FIG. 23A is a cross-sectional view of the distal end portion
of a delivery apparatus that can be used to implant a prosthetic
mitral valve in the heart, according to another embodiment.
[0039] FIG. 23B is an enlarged view of a portion of FIG. 23A
showing the connection between the valve stent and the distal end
of the delivery apparatus.
[0040] FIG. 23C is a perspective view of the delivery apparatus of
FIG. 23A.
[0041] FIGS. 23D and 23E illustrate the valve being deployed from
the delivery apparatus shown in FIG. 23A.
[0042] FIG. 24A is a perspective view of a delivery apparatus for a
prosthetic valve shown with the sheath of the delivery apparatus in
a retracted position for deploying the valve, according to another
embodiment.
[0043] FIG. 24B is a perspective view of the delivery apparatus of
FIG. 24A shown with the sheath in a distal position for covering
the valve during valve delivery.
[0044] FIG. 24C is an enlarged, perspective view of an end piece of
the delivery apparatus of FIG. 24A and three posts of a valve stent
that are received within respective recesses in the end piece.
[0045] FIG. 24D is a cross-sectional view of the end piece shown in
FIG. 24C.
[0046] FIG. 25 is a perspective view of an embodiment of a
prosthetic valve assembly having tensioning members coupled to
prosthetic leaflets of the valve to simulate chordae tendineae.
[0047] FIG. 26 is a perspective view of a prosthetic valve assembly
having tensioning members, according to another embodiment.
[0048] FIG. 27 is a perspective view of a prosthetic valve assembly
having tensioning members, according to another embodiment.
DETAILED DESCRIPTION
[0049] As used herein, the singular forms "a," "an," and "the"
refer to one or more than one, unless the context clearly dictates
otherwise.
[0050] As used herein, the term "includes" means "comprises." For
example, a device that includes or comprises A and B contains A and
B but can optionally contain C or other components other than A and
B. A device that includes or comprises A or B may contain A or B or
A and B, and optionally one or more other components such as C.
[0051] FIG. 1 is a perspective view of a mitral valve assembly 8
that can be used as a mitral valve replacement. The mitral valve
assembly 8 includes a radially compressible and expandable stent 10
having an upper portion 12 with an enlarged end, a tapered middle
portion 14 and a lower portion 16 with a circumference that is less
than that of the upper portion 12. The stent can be an inverted
bell shape, but other shapes can be used. Additionally, although
only the middle portion 14 is shown as tapered, the stent 10 can
have a continuous taper from the upper portion 12 to the lower
portion 16. An upper edge 18 of the stent 10 can be a sawtoothed or
scalloped pattern to maximize a surface area with which the stent
connects to the native tissue. Alternatively, the upper edge can be
a straight edge, or some other pattern.
[0052] The stent 10 can have a self-expanding frame 20 formed from
a shape memory material, such as, for example, Nitinol. The
illustrated embodiment shows that the stent frame 20 can include
metal strips or struts arranged in a lattice pattern, but other
patterns can be used. In certain embodiments the stent frame 20 can
be made of stainless steel or any other suitable materials. The
tapered middle portion 14 can have certain of the metal strips
intentionally disconnected from the upper portion 12 in order to
create prongs 22 extending outwardly from the stent 10 that assist
in holding the prosthetic mitral valve assembly to the native
tissue. Alternatively, barbs (not shown) can be separately attached
to the stent in order to create the prongs. One advantage of the
illustrated embodiment is that the prongs 22 are formed from the
frame itself or integral with the frame, rather than being
separately added. In other embodiments (not shown), the
disconnected metal strips can be connected, if the prongs 22 are
not desired. In such a case, each cell of the tapered portion 14
can be connected to the upper portion 12. A biocompatible sheet or
fabric material 24 can be connected to the inner surface of the
frame 20 to form an inner layer or envelope covering the open
portions of the stent to reduce paravalular leakage. The sheet or
fabric 24 can be made from synthetic materials, such as a polyester
material or a biocompatible polymer. One example of a polyester
material is polyethylene terephthalate (PET). Alternative materials
can be used. For example, the sheet or fabric can be made from
biological matter, such as natural tissue, pericardial tissue
(e.g., bovine, porcine or equine pericadium) or other biological
tissue. The sheet or fabric 24 can be connected to the frame 20 by
sutures, such as shown at 26.
[0053] As shown in dashed lines, the mitral valve assembly 8
includes a valve 28 positioned in the lower portion 16 of the stent
10. The valve 28 can have a leafed-valve configuration, such as a
bicuspid valve or tricuspid valve configuration. The valve 28 can
be connected to the frame 20 using, for example, sutures 26 or
other suitable connection techniques well-known in the art.
Alternatively, the valve 18 can be a mechanical type valve, rather
than a leafed type valve. Still further, the valve 18 can be made
from biological matter, such as natural tissue, pericardial tissue
(e.g., bovine, porcine or equine pericadium), a harvested natural
valve, or other biological tissue. Alternatively, the valve can be
made from biocompatible synthetic materials (e.g., biocompatible
polymers), which are well known in the art. Blood flow through the
valve proceeds in a direction from the upper portion 12 to the
lower portion 16. Those skilled in the art will recognize that the
particular type of valve used is not of importance and a wide
variety of valves can be used.
[0054] The features of FIG. 1 can be used in any of the embodiments
herein described. Thus, for each of the embodiments below, the
materials that can be used for the valve, the biocompatible sheet,
and the frame will not be repeated and should be assumed to be at
least those described in FIG. 1. Additionally, the prongs and barbs
of FIG. 1 can be used in any of the embodiments described
herein.
[0055] FIG. 2 is a perspective view of another embodiment of a
mitral valve assembly 38 sized for atrial implantation and designed
to work in series with the native mitral valve, as further
described below. The mitral valve assembly 38 includes a stent 40
having a frame 42 supporting a biocompatible sheet or fabric 44,
both of which are similar to those already described. The stent
supports a valve (not visible in FIG. 2) attached to and sized to
be compatible with the frame 42. Any of the valves already
described can be used. However, because of the location of the
stent 40 in the atrium, the valve can be larger than that of FIG.
1.
[0056] FIG. 3 is a perspective view of another embodiment of a
mitral valve assembly, which is the same as FIG. 2, but with prongs
45 added. More particularly, cells of the frame's lattice structure
are left intentionally disconnected from adjacent cells and are
bent outwardly to create the prongs 45. FIG. 3 is illustrative that
prongs can be added to any of the embodiments described herein.
Alternatively, the prongs can be removed from any of the
embodiments simply by leaving the lattice structure fully
connected. Furthermore, in any of the embodiments herein described,
barbs (not shown) can be separately attached to the stent in order
to create the prongs.
[0057] FIG. 4 shows another embodiment 46 of a mitral valve
assembly having an upper portion and a lower tapered portion 47.
The mitral valve assembly includes a frame 48 having a lattice
structure with certain cells of the lattice left intentionally
disconnected to create outwardly extending prongs 49, similar to
those described in relation to FIG. 1 (the prongs can be eliminated
or separate barbs added, as already described above). The lower
tapered portion 47 partially extends into the native mitral valve,
but does not extend into the left ventricle, which can improve
cardiac performance and ensure that the chordae tendineae are not
damaged by the assembly.
[0058] FIG. 5 shows a cross-sectional view of a heart with the
prosthetic mitral-valve assembly 38 inserted into a patient's
heart. For purposes of background, the four-chambered heart is
explained further. On the left side of the heart, the native mitral
valve 50 is located between the left atrium 52 and left ventricle
54. The mitral valve 50 generally comprises two leaflets, an
anterior leaflet 56 and a posterior leaflet 58 that are attached to
the left ventricle by chordae tendineae 59, which prevent eversion
of the leaflets into the left atrium. The mitral valve leaflets are
attached to a mitral valve annulus 60, which is defined as the
portion of tissue surrounding the mitral valve orifice. More
specifically, the mitral annulus constitutes the anatomical
junction between the ventricle and the left atrium, and serves an
insertion site for the leaflet tissue. The left atrium 52 receives
oxygenated blood from the pulmonary veins 61 (only two of four
pulmonary veins are shown for simplicity). The oxygenated blood
that is collected in the left atrium 52 enters the left ventricle
54 through the mitral valve 50. Contraction of the left ventricle
54 forces blood through the left ventricular outflow tract and into
the aorta (not shown). As used herein, the left ventricular outflow
tract (LVOT) is intended to generally include the portion of the
heart through which blood is channeled from the left ventricle to
the aorta. On the right side of the heart, the tricuspid valve 66
is located between the right atrium 68 and the right ventricle 70.
The right atrium 68 receives blood from the superior vena cava 72
and the inferior vena cava (not shown). The superior vena cava 72
returns de-oxygenated blood from the upper part of the body and the
inferior vena cava returns de-oxygenated blood from the lower part
of the body. The right atrium 68 also receives blood from the heart
muscle itself via the coronary sinus. The blood in the right atrium
68 enters into the right ventricle 70 through the tricuspid valve
66. Contraction of the right ventricle forces blood through the
right ventricle outflow tract and into the pulmonary arteries. The
left and right sides of the heart are separated by a wall generally
referred to as the septum 78. The portion of the septum that
separates the two upper chambers (the right and left atria) of the
heart is termed the artial (or interatrial) septum while the
portion of the septum that lies between the two lower chambers (the
right and left ventricles) of the heart is called the ventricular
(or interventricular) septum. A healthy heart has a generally
conical shape that tapers from a base to an apex 80.
[0059] The mitral valve assembly 38 is shown as positioned above
the annulus 60 of the native mitral valve 50 and entirely within
the left atrium. As already described, the stent 40 is radially
expandable and is anchored in the atrium through a pressure or
friction fit with the surrounding tissue. Through radial expansion,
the frame 42 adapts to the natural anatomy of the patient's atrium.
For purposes of illustration, a valve 90 is shown as visible
through the biocompatible sheet 44. As shown, the native mitral
valve 50 is competent and works in series with the prosthetic
mitral valve assembly 38. Any regurgitant volume that passes back
through the native valve in the left atrium is immediately blocked
by the secondary prosthetic mitral valve assembly 38. The native
valve absorbs the majority of the systolic pressure, while the
prosthetic mitral valve assembly 38 receives only a fraction of the
systolic pressure imparted by the regurgitant volume. As a result,
the prosthetic mitral valve assembly can have improved durability
and reduced risk of valve migration. Such an ability to work in
series with the native mitral valve is also true of the embodiments
described in FIGS. 6-10.
[0060] FIG. 6 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 100 inserted into
the atrium. In this embodiment, a stent 102 has a self-expanding
frame similar to stent 40 described above. The mitral valve
assembly 100 has a dome-shaped upper portion 104 that can expand to
fit the natural anatomical geometry of a roof of the atrium. As a
result, the mitral valve assembly 100 can expand in two dimensions,
such as a horizontal direction and a vertical direction. By
expanding horizontally, the mitral-valve assembly uses side walls
of the atrium to anchor the assembly. By expanding vertically, the
assembly expands between the annulus of the mitral valve and the
roof of the atrium in order to anchor the assembly in the atrium.
Thus, the roof of the atrium can exert a downward pressure on the
assembly in order to prevent upward migration. A biocompatible
sheet 106 extends from a bottom edge of the stent to some point
below the pulmonary veins 61 so that blood flow through the
pulmonary veins remains unobstructed. A valve (not shown) can be
positioned at a lower end of the assembly and works in series with
the native mitral valve, similar to the embodiments already
described.
[0061] FIG. 7 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 120 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. The assembly 120 includes a radially-expandable stent 122
that is anchored in the atrium through a pressure or friction fit.
Through radial expansion, the frame of the stent adapts to the
natural anatomy of the patient's atrium. A valve 124 is shown as
visible through a biocompatible sheet 126. As shown, the native
mitral valve 50 is competent and works in series with the
prosthetic mitral valve assembly 120. Any regurgitant volume that
passes by the native valve is blocked by the secondary prosthetic
valve assembly. As already described, the result is an assembly
with improved durability and reduced risk of valve migration. As in
the other embodiments, the biocompatible sheet 126 is attached to
the stent 122 in order to prevent paravalvular leakage. Four
anchoring arms 128 are coupled to the stent frame 122 and are
equally spaced around the frame's circumference. The opposite ends
of the anchoring arms 128 are coupled together adjacent the roof of
the atrium to create an open-ended dome. The anchoring arms 128
allow the mitral valve assembly 120 to expand in two dimensions,
such as a horizontal direction and a vertical direction. By
expanding horizontally, the mitral-valve assembly uses side walls
of the atrium to anchor the assembly. By expanding vertically, the
assembly expands between the annulus of the mitral valve and the
roof of the atrium in order to anchor the assembly in the atrium.
Thus, the roof of the atrium can exert a downward pressure on the
assembly in order to prevent upward migration. Although four
anchoring arms are shown, any number of anchoring arms can be used
(e.g., 1, 2, 3, 5, 6, etc.) Additionally, the anchoring arms 128
can be made of a flexible metal (similar or identical to the stent)
or polymer.
[0062] FIG. 8 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 140 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. This embodiment also includes anchoring arms 142, similar
to FIG. 7, except the anchoring arms 142 are coupled to a stent
frame 144 at one end and to one or more pulmonary veins 61 at an
opposite end. To couple the anchoring arms 142 to the pulmonary
veins 61, pulmonary vein stents 146 are mounted into the pulmonary
veins and are coupled to one end of the anchoring arms 142. The
pulmonary vein stents 146 can be made from the same material as
other stents described above and can be radially expandable.
Additionally, the anchoring arms 142 can be made of a flexible
metal (similar or identical to the stent) or polymer. Furthermore,
although two anchoring arms are shown, any number of anchoring arms
can be used (e.g., 1, 2, 3, or 4). As in the other embodiments, a
biocompatible sheet 150 can be attached to the stent in order to
prevent paravalvular leakage.
[0063] FIG. 9 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 160 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. The embodiment of FIG. 9 is similar to the embodiment of
FIG. 7, but with one or more anchoring arms 162, each coupled at
one end to a stent 164 and left uncoupled at an opposing end. The
anchoring arms 162 can be made of a flexible metal (similar or
identical to the stent) or polymer. Furthermore, although three
anchoring arms are shown, any number of anchoring arms can be used
(e.g., 1, 2, 3, or 4). The anchoring arms press against the roof of
the atrium to provide a pressure on the stent 164 in a direction of
the mitral valve to prevent upward migration of the stent. As in
the other embodiments, a biocompatible sheet 170 can be attached to
the stent in order to prevent paravalvular leakage.
[0064] FIG. 10 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 180 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. This embodiment is similar to the embodiment of FIG. 8,
except anchoring arms 182 are coupled to a stent frame 184 at one
end and to one or more pulmonary veins 61 at an opposite end using
threaded pulmonary vein screws 186. The threaded screws 186 are
mounted into the pulmonary veins and secure the anchoring arms in
place. The anchoring arms can therefore provide a downward pressure
on the stent frame 184 in order to resist upward migration of the
stent. The pulmonary vein screws 186 can be hollow to allow blood
to flow therethrough. Additionally, the anchoring arms 182 can be
made of a flexible metal (similar or identical to the stent) or
polymer. Furthermore, although two anchoring arms are shown, any
number of anchoring arms can be used (e.g., 1, 2, 3, or 4). As in
the other embodiments, a biocompatible sheet 190 can be attached to
the stent in order to prevent paravalvular leakage.
[0065] FIG. 11 shows a cross-sectional view of a heart with the
prosthetic mitral-valve assembly 8 from FIG. 1 inserted into a
patient's heart. As shown, the lower portion 16 can displace the
native mitral valve leaflets 56, 58. The upper portion 12 allows
for anchoring the stent 10 in the atrium. More particularly, the
stent is secured in place using contact between the radially
expanding upper portion 12 and the atrium walls. The lower portion
16 may or may not contact the native mitral valve leaflets 56, 58
as indicated by gaps 200 between the lower portion 16 and the
mitral valve 50. A valve 202 is positioned in the lower portion 16
of the stent 10 so that the portion of the stent 10 for supporting
the valve 202 is independent from the portion of the stent 10 for
anchoring the stent in the heart. As in the other embodiments, a
biocompatible sheet (not shown) can be attached to the stent in
order to prevent paravalvular leakage.
[0066] FIG. 12 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 220 inserted into
the atrium. In this embodiment, a stent 222 has a self-expanding
frame similar to stents described above. The mitral valve assembly
222 has a dome-shaped upper portion 224 that can expand to fit the
natural anatomical geometry of a roof of the atrium. As a result,
the mitral valve assembly 220 can expand in two dimensions, such as
a horizontal direction and a vertical direction, as indicated by
the arrows. By expanding horizontally, the mitral-valve assembly
uses side walls of the atrium to anchor the assembly. By expanding
vertically, the assembly expands between the annulus of the mitral
valve and the roof of the atrium in order to anchor the assembly in
the atrium. Thus, the roof of the atrium can exert a downward
pressure on the assembly in order to prevent upward migration. A
valve 226 is positioned in the lower portion 230 of the stent so
that the portion of the stent for supporting the valve 226 is
independent from the portion of the stent for anchoring the stent
in the heart. As in the other embodiments, a biocompatible sheet
(not shown) is attached to the stent in order to prevent
paravalvular leakage. However, the biocompatible sheet is desirably
not be positioned so as to obstruct blood flow through the
pulmonary veins.
[0067] FIG. 13 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 250 inserted into
the atrium. As in the other embodiments, a biocompatible sheet 252
is attached to a stent frame 254 in order to prevent paravalvular
leakage. Four anchoring arms 256 are coupled to the stent frame 254
so that they are equally spaced around the frame's circumference.
The opposite ends of the anchoring arms 256 are coupled together
adjacent the roof of the atrium to create an open-ended dome. The
anchoring arms 256 allow the mitral valve assembly 250 to expand in
two dimensions, such as a horizontal direction and a vertical
direction. By expanding horizontally, the mitral-valve assembly
uses side walls of the atrium to anchor the assembly. By expanding
vertically, the assembly expands between the annulus of the mitral
valve and the roof of the atrium in order to anchor the assembly in
the atrium. Thus, the roof of the atrium can exert a downward
pressure on the assembly in order to prevent upward migration.
Although four anchoring arms are shown, any number of anchoring
arms can be used (e.g., 1, 2, 3, 5, 6, etc.) Additionally, the
anchoring arms 256 can be made of a flexible metal (similar or
identical to the stent) or polymer.
[0068] FIG. 14 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 270 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. This embodiment also includes anchoring arms 272, similar
to FIG. 13, except the anchoring arms 272 are coupled to a stent
frame 274 at one end and to one or more pulmonary veins 61 at an
opposite end. To couple the anchoring arms 272 to the pulmonary
veins 61, pulmonary vein stents 276 are mounted into the pulmonary
veins and are coupled to one end of the anchoring arms 272. The
pulmonary vein stents 276 can be made from the same material as
other stents described herein. Additionally, the anchoring arms 272
can be made of a flexible metal (similar or identical to the stent)
or polymer. Furthermore, although two anchoring arms are shown, any
number of anchoring arms can be used (e.g., 1, 2, 3, or 4). As in
the other embodiments, a biocompatible sheet (not shown) can be
attached to the stent in order to prevent paravalvular leakage.
[0069] FIG. 15 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 290 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. The embodiment of FIG. 15 is similar to the embodiment of
FIG. 13, but with one or more anchoring arms 292, each coupled at
one end to a stent 294 and left uncoupled at an opposing end. The
anchoring arms 292 can be made of a flexible metal (similar or
identical to the stent) or polymer. Furthermore, although three
anchoring arms are shown, any number of anchoring arms can be used
(e.g., 1, 2, 3, or 4). The anchoring arms use the roof of the
atrium to provide a pressure on the stent 294 in a direction of the
mitral valve to prevent upward migration of the stent. As in the
other embodiments, a biocompatible sheet (not shown) can be
attached to the stent in order to prevent paravalvular leakage.
[0070] FIG. 16 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 300 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. This embodiment is similar to the embodiment of FIG. 14,
except anchoring arms 302 are coupled to a stent frame 304 at one
end and to one or more pulmonary veins 61 at an opposite end using
threaded pulmonary vein screws 306. The threaded screws 306 are
mounted into the pulmonary veins and secure the anchoring arms in
place. The anchoring arms can therefore provide a downward pressure
on the stent frame 304 in order to resist upward migration of the
stent. The pulmonary vein screws 306 can be hollow to allow blood
to flow therethrough. Additionally, the anchoring arms 302 can be
made of a flexible metal (similar or identical to the stent) or
polymer. Furthermore, although two anchoring arms are shown, any
number of anchoring arms can be used (e.g., 1, 2, 3, or 4). As in
the other embodiments, a biocompatible sheet (not shown) can be
attached to the stent in order to prevent paravalvular leakage.
[0071] FIG. 17 shows a cross-sectional view of a heart with the
prosthetic mitral-valve assembly from FIG. 4 inserted into a
patient's heart. As shown, the lower tapered portion 47 can
partially displace the native mitral valve leaflets 56, 58. The
upper portion allows for anchoring the stent in the atrium. More
particularly, the stent is secured in place using contact between
the radially expanding upper portion and the atrium walls. The
lower portion 47 only partially engages the native mitral valve
leaflets 56, 58, but is sized so as not to extend into the left
ventricle. As in the other embodiments, a biocompatible sheet (not
shown) can be attached to the stent in order to prevent
paravalvular leakage.
[0072] FIG. 18 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 30 inserted into
the atrium. In this embodiment, a stent has a self-expanding frame
312 similar to stents described above. The mitral valve assembly
310 has a dome-shaped upper portion 314 that can expand to fit the
natural anatomical geometry of a roof of the atrium. As a result,
the mitral valve assembly can expand in two dimensions, such as a
horizontal direction and a vertical direction. By expanding
horizontally, the mitral-valve assembly uses side walls of the
atrium to anchor the assembly. By expanding vertically, the
assembly expands between the annulus of the mitral valve and the
roof of the atrium in order to anchor the assembly in the atrium.
Thus, the roof of the atrium can exert a downward pressure on the
assembly in order to prevent upward migration. A valve 316 is
positioned in the lower portion of the stent so that the portion of
the stent for supporting the valve can be independent from the
portion of the stent for anchoring the assembly in the heart. As in
the other embodiments, a biocompatible sheet (not shown) can be
attached to the stent in order to prevent paravalvular leakage.
However, the sheet should be sized so as not to obstruct blood flow
in the pulmonary veins.
[0073] FIG. 19 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 350 inserted into
the atrium. This embodiment has characteristics of the mitral valve
assembly of FIG. 4, but with additional atrial anchoring. As in the
other embodiments, a biocompatible sheet (not shown) can be
attached to a stent frame 354 in order to prevent paravalvular
leakage. Four anchoring arms 356 are coupled to the stent frame 354
so that they are equally spaced around the frame's circumference.
The opposite ends of the anchoring arms 356 are coupled together
adjacent the roof of the atrium to create an open-ended dome. The
anchoring arms 356 allow the mitral valve assembly 350 to expand in
two dimensions, such as a horizontal direction and a vertical
direction. By expanding horizontally, the mitral-valve assembly
uses side walls of the atrium to anchor the assembly. By expanding
vertically, the assembly expands between the annulus of the mitral
valve and the roof of the atrium in order to anchor the assembly in
the atrium. Thus, the roof of the atrium can exert a downward
pressure on the assembly in order to prevent upward migration.
Although four anchoring arms are shown, any number of anchoring
arms can be used (e.g., 1, 2, 3, 5, 6, etc.) Additionally, the
anchoring arms 356 can be made of a flexible metal (similar or
identical to the stent) or polymer. A lower tapered portion 360 of
the mitral valve assembly 350 partially extends into the native
mitral valve, but can remain distant enough from the left ventricle
so as not to damage the chordae tendineae.
[0074] FIG. 20 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 400 inserted into
the atrium and a majority thereof positioned above the annulus 60
of the native mitral valve 50. This embodiment also includes
anchoring arms 402, similar to FIG. 8 with the anchoring arms 402
coupled to a stent frame 404 at one end and to one or more
pulmonary veins 61 at an opposite end. To couple the anchoring arms
402 to the pulmonary veins 61, pulmonary vein stents 406 are
mounted into the pulmonary veins and are coupled to one end of the
anchoring arms 402. The pulmonary vein stents 406 can be made from
the same material as other stents described herein. Additionally,
the anchoring arms 402 can be made of a flexible metal (similar or
identical to the stent) or polymer. Furthermore, although two
anchoring arms are shown, any number of anchoring arms can be used
(e.g., 1, 2, 3, or 4). As in the other embodiments, a biocompatible
sheet (not shown) can be attached to the stent in order to prevent
paravalvular leakage.
[0075] FIG. 21 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 420 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. The embodiment of FIG. 21 is similar to the embodiment of
FIG. 15, with one or more anchoring arms 422, each coupled at one
end to a stent 424 and left uncoupled at an opposing end. The
anchoring arms 422 can be made of a flexible metal (similar or
identical to the stent) or polymer. Furthermore, although three
anchoring arms are shown, any number of anchoring arms can be used
(e.g., 1, 2, 3, or 4). The anchoring arms use the roof of the
atrium to provide a pressure on the stent 424 in a direction of the
mitral valve to prevent upward migration of the stent. As in the
other embodiments, a biocompatible sheet (not shown) can be
attached to the stent in order to prevent paravalvular leakage.
[0076] FIG. 22 shows a cross-sectional view of a heart with another
embodiment of a prosthetic mitral-valve assembly 450 inserted into
the atrium and positioned above the annulus 60 of the native mitral
valve 50. This embodiment is similar to the embodiment of FIG. 16
with anchoring arms 452 coupled to a stent frame 454 at one end and
to one or more pulmonary veins 61 at an opposite end using threaded
pulmonary vein screws 456. The threaded screws 456 are mounted into
the pulmonary veins and secure the anchoring arms in place. The
anchoring arms can therefore provide a downward pressure on the
stent frame 454 in order to resist upward migration of the stent.
The pulmonary vein screws 456 can be hollow to allow blood to flow
therethrough. Additionally, the anchoring arms 452 can be made of a
flexible metal (similar or identical to the stent) or polymer.
Furthermore, although two anchoring arms are shown, any number of
anchoring arms can be used (e.g., 1, 2, 3, or 4). As in the other
embodiments, a biocompatible sheet (not shown) can be attached to
the stent in order to prevent paravalvular leakage.
[0077] Many of the embodiments described herein show one or more
optional extension arms 500 that are used to assist in the delivery
of the disclosed embodiments to the heart of a patient, as further
described below. The extension arms 500 are generally shown as
T-shaped extensions, but can be circular or other geometric shapes.
Likewise, the extension arms 500 can be made of metal or a suture
material.
[0078] FIGS. 23A-23E illustrate a delivery apparatus 700. The
delivery apparatus 700 comprises an outer catheter shaft 702 and an
inner catheter shaft 704 extending through the outer shaft. The
distal end portion of the outer shaft 702 comprises a sheath that
extends over a prosthetic, self-expanding stented valve 706 (shown
schematically) and retains it in a compressed state during delivery
through the patient's vasculature. The distal end portion of the
inner shaft 704 is shaped to cooperate with one or more mating
extension arms, or posts, 708 that extend from the stent of the
valve 706 to form a releasable connection between the valve and the
delivery apparatus. For example, in the illustrated embodiment each
post 708 comprises a straight portion terminating at a circular
ring portion and the distal end portion of the shaft 704 has a
correspondingly shaped recesses 710 that receive respective posts
708. Each recess 710 can include a radially extending projection
712 that is shaped to extend into an opening 714 in a respective
post 708. As best shown in FIG. 23B, each recess 710 and projection
712 can be sized to provide a small gap between the surfaces of the
post 708 and the adjacent surfaces within the recess to facilitate
insertion and removal of the post from the recess in the radial
direction (i.e., perpendicular to the axis of the shaft 704).
[0079] When the valve 706 is loaded into the delivery apparatus
700, as depicted in FIG. 23A, such that each post 708 of the valve
is disposed in a recess 710, the valve is retained against axial
movement relative to the shaft 704 (in the proximal and distal
directions) by virtue of the shape of the posts and the
corresponding recesses. Referring to FIG. 23D, as the outer shaft
702 is retracted to deploy the valve 706, the valve is allowed to
expand but is retained against "jumping" from the distal end of the
sheath by the connection formed by the posts and the corresponding
recesses for controlled delivery of the valve. At this stage the
partially deployed valve is still retained by the shaft 704 and can
be retracted back into the outer sheath 702 by retracting the shaft
704 relative to the outer sheath 702. Referring to FIG. 23E, when
the outer sheath is retracted in the proximal direction past the
posts 708, the expansion force of the valve stent causes the posts
to expand radially outwardly from the recesses 710, thereby fully
releasing the valve from the shaft 704.
[0080] While three posts 708 and corresponding recesses 710 are
shown in the illustrated embodiment, any number of posts and
recesses can be used. Furthermore, the posts and recesses can have
various other shapes, such as square, oval, rectangular,
triangular, or various combinations thereof. The posts can be
formed from the same material that is used to form the valve stent
(e.g., stainless steel or Nitinol). Alternatively, the posts can be
loops formed from less rigid material, such as suture material. The
loops are secured to the valve stent and are sized to be received
in the recesses 710.
[0081] FIGS. 24A-24D illustrate a delivery apparatus 800 that is
similar to the delivery apparatus shown in FIGS. 23A-23E. The
delivery apparatus 800 includes a handle portion 802 having a
rotatable knob 804, an outer catheter shaft 806 extending from the
handle portion 802, and an inner catheter shaft 808 extending from
the handle portion and through the outer catheter shaft 806. The
distal end of the inner catheter shaft 808 includes an end piece
810 that is formed with an annular recess 812 and a plurality of
axially extending, angularly spaced recesses 814. The recesses 812,
814 are sized and shaped to receive T-shaped posts 816 extending
from the stent of a valve (not shown in FIGS. 24A-24D). Each post
816 has an axially extending portion 816a that is received in a
corresponding recess 814 and a transverse end portion 816b that is
received in the annular recess 812. The outer shaft 806 includes a
sheath 818 that is sized and shaped to extend over the end piece
812 and the valve during delivery of the valve.
[0082] The outer shaft 806 is operatively connected to the knob 804
to effect longitudinal movement of the outer shaft 806 and the
sheath 818 relative to the inner shaft 808 upon rotation of the
knob 804. In use, the valve is mounted for delivery by placing the
posts 816 of the valve in the recesses 812, 814 and moving the
sheath distally to extend over the valve to maintain the valve in a
compressed state. At or near the target site for implanting the
valve, the knob 804 is rotated to retract the sheath 818 relative
to the valve. As the sheath is retracted to deploy the valve, the
valve is allowed to expand but is retained against "jumping" from
the distal end of the sheath by the connection formed by the posts
and the corresponding recesses for controlled delivery of the
valve. At this stage the partially deployed valve is still retained
by the end piece 810 and can be retracted back into the sheath by
moving the shaft 806 distally relative to the valve. When the
sheath is retracted in the proximal direction past the posts 816,
the expansion force of the valve stent causes the posts to expand
radially outwardly from the recesses 812, 814, thereby fully
releasing the valve from the end piece 810.
[0083] FIG. 25 shows an embodiment comprising a prosthetic mitral
valve assembly 952 having leaflets 954. Each leaflet 954 can be
connected to a respective tension member 960, the lower ends of
which can be connected at a suitable location on the heart. For
example, the lower end portions of tension members 960 can extend
through the apex 962 and can be secured in placed at a common
location outside the heart. Tension members may be attached to or
through the papillary muscles. The lower ends of tension members
can be connected to an enlarged head portion, or anchor, 964, which
secures the tension members to the apex. Tension members 960 can
extend through a tensioning block 966. The tensioning block 966 can
be configured to slide upwardly and downwardly relative to tension
members 960 to adjust the tension in the tensioning members. For
example, sliding the tensioning block 966 upwardly is effective to
draw the upper portions of the tension members closer together,
thereby increasing the tension in the tension members. The
tensioning block 966 desirably is configured to be retained in
place along the length of the tension members, such as by crimping
the tensioning block against the tension members, once the desired
tension is achieved. The tension members can be made of any
suitable biocompatible material, such as traditional suture
material, GORE-TEX.RTM., or an elastomeric material, such as
polyurethane. The tension members 960 further assist in securing
the valve assembly in place by resisting upward movement of the
valve assembly and prevent the leaflets 954 from everting so as to
minimize or prevent regurgitation through the valve assembly. As
such, the tethering de-stresses the moveable leaflets.
[0084] FIG. 26 shows another embodiment of a mitral valve assembly
1052 having prosthetic chordae tendineae. The prosthetic chordae
tendineae comprise first and second tension members 1053 connected
to a respective leaflet 1054 of the valve assembly. As shown, the
lower end portions 1056 of each tension member 1053 can be
connected at spaced apart locations to the inner walls of the left
ventricle, using, for example, anchor members 1060. A slidable
tensioning block 1076 can be placed over each tension member 1053
for adjusting the tension in the corresponding tension member. In
certain embodiments, each tension member 1053 can comprise a suture
line that extends through a corresponding leaflet 1054 and has its
opposite ends secured to the ventricle walls using anchor members
1060.
[0085] In particular embodiments, the anchor member 1060 can have a
plurality of prongs that can grab, penetrate, and/or engage
surrounding tissue to secure the device in place. The prongs of the
anchor member 1060 can be formed from a shape memory material to
allow the anchor member to be inserted into the heart in a radially
compressed state (e.g., via an introducer) and expanded when
deployed inside the heart. The anchor member can be formed to have
an expanded configuration that conforms to the contours of the
particular surface area of the heart where the anchor member is to
be deployed, such as described in co-pending application Ser. No.
11/750,272, published as US 2007-0270943 A1, which is incorporated
herein by reference. Further details of the structure and use of
the anchor member are also disclosed in co-pending application Ser.
No. 11/695,583 to Rowe, filed Apr. 2, 2007, which is incorporated
herein by reference.
[0086] Alternative attachment locations in the heart are possible,
such as attachment to the papillary muscle (not shown). In
addition, various attachment mechanisms can be used to attach
tension members to the heart, such as a barbed or screw-type anchor
member. Moreover, any desired number of tension members can be
attached to each leaflet (e.g., 1, 2, 3 . . . etc.). Further, it
should be understood that tension members can be used on any of the
embodiments disclosed herein.
[0087] FIGS. 25-26 show the use of tension members that can mimic
the function of chordae. The tethers can have several functions
including preventing the valve from migrating into the left atrium,
distressing the leaflets by preventing eversion, and preserving
ventricular function by maintaining the shape of the left
ventricle. In particular, the left ventricle can lose its shape
over time as the natural chordae become stretched or break. The
artificial chordae can help to maintain the shape. Although FIGS.
25 and 26 show a tricuspid valve, a bicuspid valve can be used
instead.
[0088] FIG. 27 shows another embodiment of a mitral valve assembly
1090 including a valve 1092 and a stent 1094 (shown partially
cut-away to expose a portion of the valve). Tension members, shown
generally at 1096, can be connected between leaflets of the valve
1092 and the stent itself. Only two leaflets are shown, but
additional tension members can be used for a third leaflet in a
tricuspid valve. In the illustrated embodiment, the tension members
1096 can include groups 2002, 2004 of three tension members each.
The three tension members 1096 of group 2002 can be attached, at
one end, to one of the leaflets at spaced intervals and converge to
attach at an opposite end to a bottom of the stent 1094. Group 2004
can be similarly connected between another of the leaflets and the
bottom of the stent 1094. The tension members 1096 can be made of
any suitable biocompatible material, such as traditional suture
material, GORE-TEX.RTM., or an elastomeric material, such as
polyurethane. The tension members can prevent the leaflets from
everting so as to minimize or prevent regurgitation through the
valve assembly. As such, the tension members de-stress the moveable
portions of the leaflets when the leaflets close during systole
without the need to connect the tension members to the inner or
outer wall of the heart.
[0089] Although groups of three tension members are illustrated,
other connection schemes can be used. For example, each group can
include any desired number of tension members (e.g., 1, 2, 3, . . .
etc.). Additionally, the tension members can connect to any portion
of the stent and at spaced intervals, if desired. Likewise, the
tension members can connect to the leaflets at a point of
convergence, rather than at spaced intervals. Further, the tension
members can be used on bicuspid or tricuspid valves. Still further,
it should be understood that tension members extending between the
stent and the leaflets can be used on any of the embodiments
disclosed herein.
[0090] One skilled in the art will recognize that the tethering
shown in FIGS. 25-27 can be used with any of the embodiments
described herein.
[0091] In view of the many possible embodiments to which the
principles of the disclosed invention may be applied, it should be
recognized that the illustrated embodiments are only preferred
examples of the invention and should not be taken as limiting the
scope of the invention. Rather, the scope of the invention is
defined by the following claims. We therefore claim as our
invention all that comes within the scope of these claims.
* * * * *