U.S. patent application number 11/357485 was filed with the patent office on 2006-08-31 for apparatus and methods for replacing a cardiac valve.
This patent application is currently assigned to The Cleveland Clinic Foundation. Invention is credited to Jose A. Navia, Jose L. Navia, Carlos Oberti.
Application Number | 20060195183 11/357485 |
Document ID | / |
Family ID | 36609618 |
Filed Date | 2006-08-31 |
United States Patent
Application |
20060195183 |
Kind Code |
A1 |
Navia; Jose L. ; et
al. |
August 31, 2006 |
Apparatus and methods for replacing a cardiac valve
Abstract
An apparatus and method for replacing a cardiac valve includes
an expandable support member having oppositely disposed first and
second ends, a main body portion extending between the ends, and a
prosthetic valve within the main body portion. The main body
portion has an annular shape for expanding into position in the
annulus of the valve. The first and second ends include a plurality
of upper and lower wing members movable from a collapsed condition
into an extended condition for respectively engaging a first
section of cardiac tissue surrounding the valve and for engaging a
portion of the native valve leaflets to pin the leaflets back
against the annulus. The second end further includes at least two
strut members spaced apart from each other. A respective one of the
strut members is attached to at least one commissural section of
the prosthetic valve to prevent prolapse of the valve leaflets.
Inventors: |
Navia; Jose L.; (Shaker
Heights, OH) ; Navia; Jose A.; (Buenos Aires, AR)
; Oberti; Carlos; (Westlake, OH) |
Correspondence
Address: |
TAROLLI, SUNDHEIM, COVELL & TUMMINO L.L.P.
1300 EAST NINTH STREET, SUITE 1700
CLEVEVLAND
OH
44114
US
|
Assignee: |
The Cleveland Clinic
Foundation
|
Family ID: |
36609618 |
Appl. No.: |
11/357485 |
Filed: |
February 18, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60654725 |
Feb 18, 2005 |
|
|
|
Current U.S.
Class: |
623/2.18 ;
623/2.11; 623/2.38 |
Current CPC
Class: |
A61F 2220/0075 20130101;
A61F 2/2457 20130101; A61F 2/2409 20130101; A61F 2230/0013
20130101; A61F 2002/8483 20130101; A61F 2/2445 20130101; A61F
2/2418 20130101; A61F 2220/0016 20130101; A61F 2/2412 20130101 |
Class at
Publication: |
623/002.18 ;
623/002.38; 623/002.11 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. An apparatus for replacing a cardiac valve having at least two
native valve leaflets, said apparatus comprising: an expandable
support member having oppositely disposed first and second ends and
a main body portion extending between said ends, said main body
portion of said support member having an annular shape for
expanding into position in the annulus of the cardiac valve; said
first end of said support member comprising a plurality of upper
wing members that extend from said main body portion, each of said
upper wing members being movable from a radially collapsed
condition into a radially extended condition for engaging a first
section of cardiac tissue surrounding one-side of the cardiac
valve; said second end of said support member comprising a
plurality of lower wing members that extend from said main body
portion, each of said lower wing members being movable from a
radially collapsed condition into a radially extended condition for
engaging a portion of the native valve leaflets to pin the leaflets
back against the annulus of the native cardiac valve; said second
end of said support member further including at least two strut
members that are spaced apart from each other; and a prosthetic
valve secured within said main body portion of said support member,
said prosthetic valve having at least two valve leaflets that are
coaptable to permit unidirectional flow of blood, each of said at
least two valve leaflets being joined together at at least two
commissural sections that are spaced apart from each other, each of
said at least two commissural sections being attached to a
respective one of said strut members to prevent prolapse of said
valve leaflets.
2. The apparatus of claim 1 wherein said plurality of upper wing
members, in their radially extended condition, extend transverse to
the direction of blood flow through said prosthetic valve.
3. The apparatus of claim 1 wherein at least one of said plurality
of upper wing members includes at least one attachment mechanism
for embedding into the first section of cardiac tissue to help
secure said support member in the annulus of the cardiac valve.
4. The apparatus of claim 3 wherein said at least one attachment
mechanism includes at least one barb.
5. The apparatus of claim 1 wherein at least one of said plurality
of lower wing members includes at least one attachment mechanism
for embedding into a portion of the native valve leaflets to help
secure said support member in the annulus of the cardiac valve.
6. The apparatus of claim 1 wherein said main body portion has a
concave cross-sectional shape for conforming to the convex shape of
the annulus of the cardiac valve.
7. The apparatus of claim 1 wherein said plurality of lower wing
members includes first and second lower wing members for
positioning at the commissures of the native cardiac valve.
8. The apparatus of claim 7 wherein said first and second lower
wing members are spaced approximately 180.degree. apart.
9. The apparatus of claim 8 wherein said plurality of lower wing
members further includes third and fourth lower wing members for
positioning directly over respective central portions of the at
least two native valve leaflets.
10. The apparatus of claim 9 wherein said third and fourth lower
wing members are spaced approximately 180.degree. apart and are
located in-between said first and second lower wing members,
respectively.
11. The apparatus of claim 1 wherein said plurality of lower wing
members includes a first group of lower wing members for
positioning at the commissures of the native cardiac valve.
12. The apparatus of claim 11 wherein said plurality of lower wing
members further includes a second group of lower wing members for
positioning directly over respective central portions of the at
least two native valve leaflets, said first and second groups of
lower wing members being arranged in an alternating fashion.
13. The apparatus of claim 1 wherein said plurality of lower wing
members includes at least two lower wing members for positioning
directly over respective central portions of the at least two
native valve leaflets.
14. The apparatus of claim 1 further comprising a layer of
biocompatible material covering at least a portion of said support
member.
15. The apparatus of claim 1 wherein at least a portion of said
support member is treated with at least one therapeutic agent for
eluting into cardiac tissue.
16. The apparatus of claim 1 wherein a plurality of portions of
said support member are separately treated with a different
therapeutic agent.
17. A method for replacing a cardiac valve having at least two
native valve leaflets, said method comprising the steps of:
providing a prosthetic valve that includes an expandable support
member having oppositely disposed first and second ends and a main
body portion extending between the ends, a plurality of upper wing
members that extend from a one end of the main body portion, and a
plurality of lower wing members that extend from an opposite end of
the main body portion, the second end of the support member further
including at least two strut members, the prosthetic valve having
at least two valve leaflets that are joined together at at least
two commissural sections, each of the at least two commissural
sections being attached to a respective one of the strut members to
prevent prolapse of the valve leaflets; placing the main body
portion of the prosthetic valve within the annulus of the cardiac
valve to be replaced; expanding the main body portion into
engagement with the annulus of the cardiac valve to secure the
prosthetic valve in the annulus; deploying the upper wing members
from a radially collapsed condition into a radially extended
condition into engagement with a first section of cardiac tissue
surrounding one side of the cardiac valve; and deploying the lower
wing members from a radially collapsed condition into a radially
extended condition into engagement with a portion of the native
valve leaflets to pin the leaflets back against the annulus of the
native cardiac valve.
18. The method of claim 17 wherein said step of placing the main
body portion of the prosthetic valve within the annulus of the
cardiac valve to be replaced further comprises the steps of:
placing the support member around an inflatable balloon in a
secured manner; inserting the balloon and support member into an
atrial chamber; advancing the balloon until the support member is
positioned within the annulus of the cardiac valve to be replaced;
and expanding the support member with the balloon so that the
support member engages the annulus of the cardiac valve to secure
the support member in the annulus.
19. The method of claim 18 wherein the balloon has an hourglass
shape defined by first and second bulb sections connected by a
center section having a smaller diameter than the bulb sections,
said step of placing the support member around the balloon further
comprising the step of positioning the support member about the
center section.
20. The method of claim 19 wherein said step of advancing the
balloon until the support member is positioned within the valve
annulus further includes the step of positioning the first bulb
section within the leaflets of the native valve so that when the
balloon is inflated the first bulb pushes the valve leaflets back
to protect the leaflets during expansion of the support member.
21. The method of claim 18 wherein said step of expanding the
support member with the balloon so that the support member engages
the annulus of the cardiac valve includes the step of conforming
the main body portion to the shape of the valve annulus to help
locate and secure the support member in the valve annulus by
radially forcing the main body portion into the valve annulus.
22. The method of claim 17 wherein each of the plurality of wing
members include at least one attachment mechanism for embedding
into cardiac tissue.
23. The method of claim 22 wherein the attachment mechanism
includes at least one barb extending from each of the wing members,
said method further including the step of embedding the at least
one barb into cardiac tissue to further secure the support member
in the valve annulus.
24. The method of claim 23 wherein each of the wing members has a
concave cross-sectional shape for conforming to the convex shape of
the valve annulus, said method further comprising the step of
pulling the wing members into a flatter cross-sectional shape with
a constraining wire for placement of the support member, the at
least one barb extending generally radially when the wing members
are being held by the constraining wire.
25. The method of claim 24 further comprising the step of releasing
the constraining wire after said step of expanding the support
member with the balloon so that the upper wing members spring
radially outward to engage the first section of cardiac tissue, and
the lower wing members spring radially outward to engage a portion
of the native valve leaflets.
26. The method of claim 25 wherein said step of releasing the
constraining wire causes the at least one barb to embed into
cardiac tissue in the distal direction.
27. The method of claim 17 wherein said step of inserting the
balloon and the prosthetic valve into the heart chamber is done
percutaneously via an intravascular catheter.
28. The method of claim 27 wherein said step of inserting the
balloon and the prosthetic valve into the heart chamber is done via
a minimally invasive approach.
29. The method of claim 27 wherein said step of inserting the
balloon and the prosthetic valve into the heart chamber is done via
an open-chest procedure.
30. The method of claim 17 wherein at least a portion of the
support member is treated with at least one therapeutic agent for
eluting into cardiac tissue, the method further comprising the step
of allowing the at least one therapeutic agent to elute into the
cardiac tissue.
Description
RELATED APPLICATION
[0001] This application claims priority from U.S. provisional
patent application Ser. No. 60/654,725, filed on Feb. 18, 2005, the
subject matter of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an apparatus and methods
for treating a diseased cardiac valve, and is particularly directed
to an apparatus and methods for the correction of mitral valve and
tricuspid valve disorders via a minimally invasive or percutaneous
approach.
BACKGROUND OF THE INVENTION
[0003] There are two atrio-ventricular valves in the heart; one on
the left side of the heart and one on the right side of the heart.
The left side atrio-ventricular valve is the mitral valve and the
right side atrio-ventricular
[0004] The mitral and tricuspid valves differ significantly in
anatomy. While the annulus of the mitral valve is generally
D-shaped, the annulus of the tricuspid valve is more circular. The
effects of the valvular dysfunction vary between the mitral valve
and the tricuspid valve. Mitral valve regurgitation has more severe
physiological consequences to the patient than does tricuspid valve
regurgitation, a small amount of which is tolerable.
[0005] In mitral valve insufficiency, the valve leaflets do not
fully close and a certain amount of blood leaks back into the left
atrium when the left ventricle contracts. As a result, the heart
has to work harder by pumping not only the regular volume of the
blood, but also the extra volume of blood that regurgitated back
into the left atrium. The added workload creates an undue strain on
the left ventricle. This strain can eventually wear out of the
heart and result in morbidity when the conditions are prolonged and
severe enough. Consequently, proper function of the mitral valve is
critical to the pumping efficiency of the heart.
[0006] Mitral and tricuspid valve disease is traditionally treated
by either surgical repair with an annuloplasty ring or surgical
replacement with a valve prosthesis. However, surgical valve
replacement or repair is often an exacting operation that is done
through a surgical technique where the thoracic cavity is opened.
The operation requires use of a heart-lung machine for external
circulation of the blood as the heart is stopped and opened during
the surgical intervention and the artificial cardiac valves and/or
annuloplasty rings are sewed in under direct vision. This operation
exposes the patient to many risks especially in the elderly
population. A percutaneous procedure that can be performed under
local anesthesia in the cardiac catherization lab, rather than in
cardiac surgery, could therefore offer tremendous benefits for
these patients, many of whom have no options today. Consequently,
an apparatus for replacing a diseased atrioventricular valve using
a minimally invasive, percutaneous approach would be very helpful
to provide additional opportunities to treat patients with severe
valvular insufficiency, end stage heart failure, atrial
fibrillation, and/or other associated arrhythmias.
SUMMARY OF THE INVENTION
[0007] In one aspect of the present invention, an apparatus for
replacing a cardiac valve having at least two native valve leaflets
is provided. The apparatus comprises an expandable support member
having oppositely disposed first and second ends and a main body
portion extending between the ends. The main body portion of the
support member has an annular shape for expanding into position in
the annulus of the cardiac valve. The first end comprises a
plurality of upper wing members that extend from the main body
portion. Each of the upper wing members is movable from a radially
collapsed condition into a radially extended condition for engaging
a first section of cardiac tissue surrounding one side of the
cardiac valve. The second end comprises a plurality of lower wing
members that extend from the main body portion. Each of the lower
wing members is movable from a radially collapsed condition into a
radially extended condition for engaging a portion of the native
valve leaflets to pin the leaflets back against the annulus of the
native cardiac valve. The second end of the support member further
includes at least two strut members that are spaced apart from each
other. The at least two valve leaflets are joined at at least two
commissural sections that are spaced apart from each other. Each of
the at least two commissural sections are attached to a respective
one of the strut members to prevent prolapse of the valve leaflets.
A prosthetic valve is secured within the main body portion of the
support member. The prosthetic valve has at least two valve
leaflets that are coaptable to permit unidirectional flow of
blood.
[0008] In another aspect of the present invention, at least a
portion of the support member is treated with at least one
therapeutic agent for eluting into cardiac tissue.
[0009] In yet another aspect of the present invention, a method for
replacing a cardiac valve having at least two native valve leaflets
is provided. According to the inventive method, a prosthetic valve
having at least two valve leaflets that are coaptable to permit
unidirectional flow of blood is provided. The prosthetic valve
includes an expandable support member having oppositely disposed
first and second ends and a main body portion extending between the
ends. The expandable support member further includes a plurality of
upper wing members that extend from one end of the main body
portion, and a plurality of lower wing members that extend from an
opposite end of the main body portion. The second end of the
support member further includes at least two strut members. The
prosthetic valve includes at least two valve leaflets that are
joined together at at least two commissural sections. Each of the
at least two commissural sections are attached to a respective one
of the strut members to prevent prolapse of the valve leaflets. The
main body portion of the prosthetic valve is placed within the
annulus of the cardiac valve to be replaced, and is then expanded
into engagement with the annulus of the cardiac valve to secure the
prosthetic valve in the annulus. The upper wing members are
deployed from a radially collapsed condition into a radially
extended condition into engagement with a first section of cardiac
tissue surrounding one side of the cardiac valve. The lower wing
members are deployed from a radially collapsed condition into a
radially extended condition into engagement with a portion of the
native valve leaflets to pin the leaflets back against the annulus
of the native cardiac valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing and other features of the present invention
will become apparent to those skilled in the art to which the
present invention relates upon reading the following description
with reference to the accompanying drawings, in which:
[0011] FIG. 1 is a schematic sectional view of an apparatus for
replacing a diseased cardiac valve in accordance with the present
invention and illustrating the apparatus being delivered to the
diseased valve in a collapsed condition through a percutaneous
procedure;
[0012] FIG. 2 is a perspective view of the apparatus of FIG. 1 in a
radially expanded condition;
[0013] FIG. 3 is a perspective view showing an alternative
embodiment of the apparatus in FIG. 2;
[0014] FIG. 4 is a perspective view showing another alternative
embodiment of the apparatus shown in FIG. 2;
[0015] FIG. 5 is a view similar to FIG. 1 illustrating the
placement of the apparatus in the annulus of the cardiac valve in
the expanded condition;
[0016] FIG. 6 is a schematic sectional view taken along 6-6 in FIG.
5;
[0017] FIG. 7 is a schematic top view taken along line 7-7 in FIG.
5 with parts omitted for clarity;
[0018] FIG. 8 is a schematic bottom view taken along line 8-8 in
FIG. 5 with parts omitted for clarity;
[0019] FIG. 9 is a plan view of the apparatus in FIG. 4
illustrating an alternative embodiment of the apparatus;
[0020] FIG. 10 is a view similar to FIG. 9 illustrating another
alternative construction of the apparatus;
[0021] FIG. 11 is a perspective view showing an alternative
embodiment of the apparatus in FIG. 4 having artificial chordae;
and
[0022] FIG. 12 is a schematic top view similar to FIG. 7 and
illustrating an alternate embodiment of the apparatus.
DETAILED DESCRIPTION OF EMBODIMENTS
[0023] The present invention relates to an apparatus and methods
for treating a diseased cardiac valve, and is particularly directed
to an apparatus and methods for the correction of mitral valve and
tricuspid valve disorders via a minimally invasive and/or
percutaneous approach. As representative of the present invention,
FIGS. 1 and 2 illustrate an apparatus 10 that includes a prosthetic
valve 12 for replacing a dysfunctional cardiac valve, such as a
mitral valve 14, by inserting the prosthetic valve over the native
mitral valve so that the prosthetic valve assumes the valvular
function. It should be understood, however, that the apparatus 10
disclosed herein could also be used to replace other cardiac
valves, such as a tricuspid, pulmonary, or aortic valve.
[0024] As shown in FIG. 1, the mitral valve 14 is located between
the left atrium 16 and the left ventricle 18 and functions to
prevent the backflow of blood from the left ventricle into the left
atrium during contraction. The mitral valve 14 has a D-shaped
annulus 20 that defines the opening between the left atrium 16 and
the left ventricle 18. The mitral valve 14 is formed by two
leaflets; namely, the anterior leaflet 22 and the posterior leaflet
24 (FIG. 6). The anterior leaflet 22 extends along the generally
planar base of the D-shaped valve annulus 20, while the posterior
leaflet 24 extends arcuately around the curved portion of the
D-shaped annulus of the mitral valve 14. Chordae tendinea 26 (FIG.
1) extend between the free edges 28 of both leaflets 22 and 24 to
the papillary muscles 30 in the left ventricle 18.
[0025] The apparatus 10 for replacing the dysfunctional mitral
valve 14 includes an expandable support member 40 (FIG. 2),
commonly referred to as a stent, and the prosthetic valve 12. The
support member 40 has a known stent configuration that allows it to
be collapsed and expanded. The support member 40 may be made from
any suitable medical grade metal or plastic, including shape memory
materials such as Nitinol, stainless steel, and/or titanium.
[0026] The support member 40 is annular in shape and includes
oppositely disposed first and second ends 42 and 44 with a main
body portion 46 extending between the ends. As shown in FIGS. 2-8,
when the support member 40 is expanded, the main body portion 46
has a concave cross-sectional shape for conforming to the convex
shape of the valve annulus 20.
[0027] The apparatus 10 may further include a layer 50 (FIG. 3) of
biocompatible material covering at least a portion of the support
member 40. The layer 50 of biocompatible material may be a
synthetic such as Dacron.RTM. (Invista, Wichita, Kans.),
Gore-Tex.RTM. (W. L. Gore & Associates, Flagstaff, Ariz.),
woven velour, polyurethane, polytetrafluoroethylene (PTFE), or
heparin-coated fabric. Alternatively, the layer 50 may be a
biological material such as bovine or equine pericardium,
peritoneal tissue, an allograft, a homograft, patient graft, or a
cell-seeded tissue. The layer 50 can cover either the inside
surface of the support member 40, the outside surface of the
support member, or can be wrapped around both the inside and
outside surfaces. The layer 50 may be attached around the entire
circumference of the support member 40 or, alternatively, may be
attached in pieces or interrupted sections to allow the support
member to more easily expand and contract. As shown in FIG. 3, for
example, only the main body portion 46 of the prosthetic valve 12
may be covered with the layer 50 of biocompatible material.
Alternatively, the support member 40 may be entirely covered with
the layer 50 of biocompatible material (FIG. 4).
[0028] The first end 42 of the support member 40 comprises a
plurality of upper wing members 60 that extend integrally from the
main body portion 46. In the embodiment illustrated in FIGS. 1-8,
there are four upper wing members 60 spaced about the circumference
of the support member 40, but it should be understood that more or
less than four upper wing members could be used. The upper wing
members 60 are movable from the radially collapsed condition of
FIG. 1 to the radially extended condition of FIGS. 2-8. Each upper
wing member 60 may also include at least one attachment mechanism
62, such as a barb 64 or suture, for embedding into a first section
of cardiac tissue (e.g., the wall of the left atrium 16) to help
secure the support member 40 in the annulus 20 of the mitral valve
14.
[0029] The second end 44 of the support member 40 comprises a
plurality of lower wing members 70 that extend integrally from the
main body portion 46. In the embodiment illustrated in FIGS. 1-8,
there are four lower wing members 70 spaced about the circumference
of the support member 40. More specifically, there are first and
second lower wing members 72 and 74, spaced approximately
180.degree. apart, for positioning at the commissures of the native
mitral valve 14, and third and fourth lower wing members 76 and 78
(FIG. 7), spaced approximately 180.degree. apart, for positioning
directly over respective central portions of the native leaflets 22
and 24. The third and fourth lower wing members 76 and 78 are
spaced in-between the first and second lower wing members 72 and
74, respectively. It is contemplated, however, that more or less
than four lower wing members 70 could be used. Further, it is
contemplated that the third and fourth lower wing members 76 and 78
positioned over the leaflets 22 and 24 could be omitted
completely.
[0030] Each of the lower wing members 70 is movable from the
radially collapsed condition of FIG. 1 to the radially extended
condition of FIGS. 2-8 for engaging a portion of the native valve
leaflets 22 and 24 to pin the leaflets back against the native
valve annulus 20. The lower wing members 70 may also include at
least one attachment mechanism 62, such as a barb 64 or suture, for
embedding into at least one of the native valve leaflets 22 and 24
to help secure the support member 40 in the annulus 20 of the
mitral valve 14.
[0031] The second end 44 of the support member 40 additionally
includes at least two strut members 45. As shown in FIG. 2, the
valve leaflets of the prosthetic valve 12 are joined together at at
least two commissural sections 47 that are spaced apart from each
other. Each of the at least two commissural sections 47 are
attached to a representative one of the strut members 45 to prevent
prolapse of prosthetic valve leaflets 90 and 92, described in
detail below. The strut members 45 are securely attached to, and
extend in a generally axial manner from, the support member 40. The
strut members 45 are securely connected to the prosthetic valve 12
by sutures, for example, and may be made from any suitable medical
grade metal or plastic, including shape memory materials such as
Nitinol, stainless steel, and/or titanium. As illustrated in FIG.
2, the strut members 45 have a bare metal configuration and do not
extend beyond the length of the prosthetic valve 12. It is
contemplated, however, that the configuration of the strut members
45 may be varied as needed. For example, the strut members 45 may
be covered by a layer 50 of biocompatible material and extend
beyond the length of the prosthetic valve 12.
[0032] The prosthetic valve 12 of the present invention may
comprise a stentless prosthetic valve. By "stentless" it is meant
that the valve components including the leaflets of the prosthetic
valve 12 are not reinforced with a support structure, such as a
stent or other similar structure. The prosthetic valve 12 is
secured, for example, by sutures or other suitable means within the
main body portion 46 of the support member 40.
[0033] The prosthetic valve 12 may be fixed and preserved using a
variety of known methods. The use of chemical processes for the
fixation and preservation of biological tissues have been described
and are readily available in the art. For example, glutaraldehyde,
and other related aldehydes have seen widespread use in preparing
cross-linked biological tissues.
[0034] Glutaraldehyde is a five carbon aliphatic molecule with an
aldehyde at each end of the chain, rendering it bifunctional. These
aldehyde groups react under physiological conditions with primary
amine groups on collagen molecules resulting in the cross-linking
of collagen containing tissues. Methods for glutaraldehyde fixation
of biological tissues have been extensively described and are well
known in the art. In general, a tissue sample to be cross-linked is
simply contacted with a glutaraldeyde solution for a duration
effective to cause the desired degree of cross-linking within the
biological tissue being treated.
[0035] Many variations and conditions have been applied to optimize
glutaraldehyde fixation procedures. For example, lower
concentrations have been found to be better in bulk tissue
cross-linking compared to higher concentrations. It has been
proposed that higher concentrations of glutaraldehyde may promote
rapid surface cross-linking of the tissue, generating a barrier
that impedes or prevents the further diffusion of glutaraldehdye
into the tissue bulk. For most bioprosthesis applications, the
tissue is treated with a relatively low concentration
glutaraldehyde solution, e.g., typically between 0.1%-5%, for 24
hours or more to ensure optimum fixation. Various other
combinations of glutaraldehyde concentrations and treatment times
will also be suitable depending on the objectives for a given
application. Examples of such other combinations include, but are
not limited to, U.S. Pat. Nos. 6,547,827, 6,561,970, and 6,878,168,
all of which are hereby incorporated by reference in their
entirety.
[0036] In addition to bifunctional aldehydes, many other chemical
fixation procedures have been described. For example, some such
methods have employed polyethers, polyepoxy compounds,
diisocyanates, and azides. These and other approaches available to
the skilled individual in the art for treating biological tissues
are suitable for cross-linking vascular graft tissue according to
the present invention.
[0037] The prosthetic valve 12 may also be treated and preserved
with a dry tissue valve procedure as described in U.S. Pat. No.
6,534,004, the entire contents of which are hereby incorporated by
reference. Furthermore, the prosthetic valve 12 may be treated with
anti-calcification solutions, such as XenoLogiX.RTM. treatment
(Edwards Lifesciences, Irvine, Calif.) or the SynerGraft.RTM.
(CryoLife, Inc., Kennesaw, Ga.) treatment process, and/or
anti-calcification agents, such as alfa-amino oleic acid.
[0038] The prosthetic valve 12 can be made with only one piece of
pericardial tissue, for example, as shown in FIG. 9. Where a single
piece of pericardial tissue is used, a seam 96 is formed by
suturing the ends of the tissue. Alternatively, the prosthetic
valve 12 can be made with two pieces of pericardial tissue, one of
which will form the first leaflet 90 and the other forms the second
leaflet 92 of the prosthetic valve, as may be seen in FIG. 10.
Where two pieces of pericardial tissue are used (FIG. 10), it is
necessary to suture the tissue in two locations, thereby forming
two seams 98 and 100. The seams 96, 98, and 100 are always placed
at what will be the commissures of the prosthetic valve 12, where
the first leaflet 90 meets the second leaflet 92.
[0039] FIG. 11 illustrates an alternative embodiment of the present
invention. The apparatus 10.sub.a of FIG. 11 is identically
constructed as the apparatus 10 of FIGS. 2-8, except whereas
described below. In FIG. 11, structures that are identical as
structures in FIGS. 2-8 use the same reference numbers, whereas
structures that are similar but not identical carry the suffix
"a".
[0040] As shown in FIG. 11, the apparatus 10.sub.a includes an
expandable support member 40 having a flexible configuration and a
prosthetic valve 12.sub.a. The support member 40 is annular in
shape and includes oppositely disposed first and second ends 42 and
44 with a main body portion 40 extending between the ends. The
apparatus 10.sub.a may further include a layer 50 of biocompatible
material covering at least a portion of the support member 40.
[0041] The first and second ends 42 and 44 of the support member 40
respectively comprises a plurality of upper and lower wing members
60 and 70 that extend integrally from the main body portion 46. The
upper and lower wing members 60 and 70 are movable from the
radially collapsed condition of FIG. 1 to the radially extended
condition of FIG. 11. Each upper wing member 60 may also include at
least one attachment mechanism 62, such as a barb 64 or suture, for
embedding into a first section of cardiac tissue (e.g., the wall of
the left atrium 16) to help secure the support member 40 in the
annulus 20 of the mitral valve 14. The lower wing members 70 may
also include at least one attachment mechanism 62, such as a barb
64 or suture, for embedding into at least one of the native valve
leaflets 22 and 24 to help secure the support member 40 in the
annulus 20 of the mitral valve 14.
[0042] The prosthetic valve 12.sub.a of the apparatus 10.sub.a (and
also the previously described valve 12) may comprise a stentless
prosthetic valve, for example, having dimensions that correspond to
the dimensions of the native mitral valve 14. Where the prosthetic
valve 12.sub.a is comprised of biological material, the biological
material can include a harvested biological material such as bovine
pericardial tissue, equine pericardial tissue, porcine pericardial
tissue, animal or human peritoneal tissue, or mitral, aortic, and
pulmonary xenograft or homograft. The biocompatible material may
also include a suitable synthetic material such as polyurethane,
expanded PTFE, woven velour, Dacron.RTM., heparin-coated fabric, or
Gore-Tex.RTM..
[0043] The prosthetic valve 12.sub.a further includes first and
second leaflets 90 and 92 that mimic the three-dimensional
anatomical shape of the anterior and posterior leaflets 22 and 24,
respectively, of the mitral valve 14. The valve leaflets of the
prosthetic valve 12.sub.a are joined together at at least two
commissural sections 47 that are spaced apart from each other. The
prosthetic valve 12.sub.a also includes a distal end 86 that
defines a first annulus 94 at which the first and second leaflets
90 and 92 terminate.
[0044] Additionally, the prosthetic valve 12.sub.a includes first
and second pairs 102 and 104, respectively, of prosthetic chordae
106 that project from the first and second leaflets 90 and 92 at
the first annulus 94. Each of the prosthetic chordae 106 comprises
a solid uninterrupted extension of biocompatible material. Each of
the first pair 102 of prosthetic chordae 106 has a distal end 108
and each of the second pair 104 of prosthetic chordae has a distal
end 110.
[0045] As shown in FIG. 11, the second end 44 of the support member
40 may additionally include at least two strut members 45.sub.a
spaced apart from each other. Each of the at least two commissural
sections 47 of the prosthetic valve 12.sub.a are attached to a
respective one of the strut members 45 to prevent prolapse of the
valve leaflets 90 and 92. The strut members 45.sub.a are integrally
connected to the support member 40 and extend in a generally axial
manner along the prosthetic valve 12.sub.a. The strut members
45.sub.a may be attached to the distal ends 108 of the first pair
102 of the prosthetic chordae 106 by sutures, for example.
Alternatively, the strut members 45.sub.a may be attached to the
distal ends 110 of the second pair 104 of the prosthetic chordae
106. It is contemplated that the configuration of the strut members
45.sub.a may be varied as needed. For instance, the strut members
45.sub.a may have a shorter length than the length of the strut
members illustrated in FIG. 11. In this instance, the strut members
45.sub.a may be attached at a position proximal to the distal ends
108 and 110 of the prosthetic chordae 106, such as at or near the
first annulus 94 of the prosthetic valve 12.sub.a.
[0046] The present invention may be treated with at least one
therapeutic agent capable of preventing a variety of pathological
conditions including, but not limited to, thrombosis, restenosis
and inflammation. Accordingly, the therapeutic agent may include at
least one of an anticoagulant, an antioxidant, a fibrinolytic, a
steroid, an anti-apoptotic agent, and/or an anti-inflammatory
agent.
[0047] Optionally or additionally, the therapeutic agent may be
capable of. treating or preventing other diseases or disease
processes such as microbial infections, arrhythmias, and/or heart
failure. In these instances, the therapeutic agent may include an
antiarrhythmic agent, an inotropic agent, a chronotropic agent,
and/or a biological agent such as a cell or protein. More specific
types of these therapeutic agents are listed below, including other
types of therapeutic agents not discussed above.
[0048] Examples of acceptable therapuetic agents include Coumadin,
heparin, synthetic heparin analogues (e.g., fondaparinux), G(GP)
II.sub.b/III.sub.a inhibitors, vitronectin receptor antagonists,
hirudin, antithrombin III, drotrecogin alpha; fibrinolytics such as
alteplase, plasmin, lysokinase, factor XIIa, factor VIIa,
prourokinase, urokinase, streptokinase; thrombocyte aggregation
inhibitors such as ticlopidine, clopidogrel, abciximab, dextrans;
corticosteroids such as aldlometasones, amcinonides, augmented
betamethasones, beclomethasones, betamethasones, budesonides,
cortisones, clobetasol, clocortolones, desonides, desoximetasones,
dexamethasones, flucinolones, fluocinonides, flurandrenolides,
flunisolides, fluticasones, halcinonides, halobetasol,
hydrocortisones, methylprednisolones, mometasones, prednicarbates,
prednisones, prednisolones, triamcinolones; fibrinolytic agents
such as tissue plasminogen activator, streptokinase, dipyridamole,
ticlopidine, clopidine, and abciximab; non-steroidal
anti-inflammatory drugs such as salicyclic acid and salicyclic acid
derivatives, para-aminophenol derivatives, indole and indene acetic
acids (e.g., etodolac, indomethacin, and sulindac), heteroaryl
acetic acids (e.g., ketorolac, diclofenac, and tolmetin),
arylpropionic acids (e.g., ibuprofen and derivatives thereof),
anthranilic acids (e.g., meclofenamates and mefenamic acid), enolic
acids (e.g., piroxicam, tenoxicam, phenylbutazone, and
oxyphenthatrazone), gold compounds (e.g., auranofin,
aurothioglucose, and gold sodium thiomalate), diflunisal,
meloxicam, nabumetones, naproxen, oxaprozin, salsalate, celecoxib,
rofecoxib; cytostatics such as alkaloids and podophyllum toxins
such as vinblastin, vincristin; alkylants such as nitrosoureas and
nitrogen lost analogues; cytotoxic antibiotics such as
daunorubicin, doxorubicin, and other anthracyclins and related
substances, bleomycin, and mitomycin; antimetabolites such as folic
acid analogues, purine analogues and related inhibitors (e.g.,
mercaptopurine, thioguanine, pentostatin, and
2-chlorodeoxyadenosine), pyrimidine analogues (e.g., fluorouracil,
floxuridine, and cytarabine), and platinum coordination complexes
(e.g., cisplatinum, carboplatinum and oxaliplatinum); tacrolimus,
azathioprine, cyclosporine, paclitaxel, docetaxel, sirolimus;
amsacrin, irinotecan, imatinib, topotecan, interferon-alpha 2a,
interferon-alpha 2b, hydroxycarbamide, miltefosin, pentostatin,
porfimer, aldesleukin, bexarotene, and tretinoin; antiandrogens and
antiestrogens; antiarrythmics, in particular antiarrhythmics of
class I such as antiarrhythmics of the quinidine type (e.g.,
quinidine, dysopyramide, ajmaline, prajmalium bitartrate, and
detajmium bitartrate); antiarrhythmics of the lidocaine type,
(e.g., lidocaine, mexiletin, phenyloin, and tocainid);
antiarrhythmics of class I C (e.g., propafenone, flecainide
(acetate)); antiarrhythmics of class II, including betareceptor
blockers such as metoprolol, esmolol, propranolol, metoprolol,
atenolol, and oxprenolol; antiarrhythmics of class III such as
amiodaron and sotalol; antiarrhythmics of class IV such as
diltiazem, and verapamil; and other antiarrhythmics such as
adenosine, orciprenaline, and ipratropium bromide.
[0049] Other types of therapeutic agents may include digitalis
glycosides such as acetyl digoxin/methyldigoxin, digitoxin, and
digoxin; heart glycosides such as ouabain and proscillaridin;
antihypertensives such as centrally effective antiadrenergic
substances (e.g., methyldopa and imidazoline receptor agonists);
calcium channel blockers of the dihydropyridine type, such as
nifedipine and nitrendipine; ACE inhibitors (e.g., quinaprilate,
cilazapril, moexipril, trandolapril, spirapril, imidapril, and
trandolapril); angiotensin-II-antagonists (e.g.,
candesartancilexetil, valsartan, telmisartan, olmesartan medoxomil,
and eprosartan); peripherally effective alpha-receptor blockers
such as prazosin, urapidil, doxazosin, bunazosin, terazosin, and
indoramin; vasodilators such as dihydralazine, diisopropyl amine
dichloroacetate, minoxidil, and nitropiusside-sodium; other
antihypertonics such as indapamide, codergocrin mesilate,
dihydroergotoxin methane sulphonate, cicletanin, bosentan, and
fludrocortisone; phosphodiesterase inhibitors, such as milrinone
and enoximone, as well as antihypotonics (e.g., adrenergics and
dopaminergic substances such as dobutamine, epinephrine,
etilefrine, norfenefrine, norepinephrine, oxilofrine, dopamine,
midodrine, pholedrine, and amezinium methyl) and partial
adrenoceptor agonists (e.g., dihydroergotamine); fibronectin,
polylysines and ethylene vinyl acetates; and adhesive substances
such as cyanoacrylates, beryllium, and silica.
[0050] Additional therapeutic agents may also include antibiotics
and antiinfectives such as .beta.-lactam antibiotics (e.g.,
.beta.-lactamase-sensitive penicillins, including benzyl
penicillins (penicillin G) and phenoxymethylpenicillin (penicillin
V)); .beta.-lactamase-resistant penicillins, such as
aminopenicillins, which include amoxicillin, ampicillin, and
bacampicillin; acylaminopenicillins such as mezlocillin and
piperacillin; carboxypenicillines and cephalosporins (e.g.,
cefazolin, cefuroxim, cefoxitin, cefotiam, cefaclor, cefadroxil,
cefalexin, loracarbef, cefixim, cefuroximaxetil, ceftibuten,
cefpodoximproxetil, and cefpodoximproxetil); aztreonam, ertapenem,
and meropenem; .beta.-lactamase inhibitors such as sulbactam and
sultamicillintosilates; tetracyclines such as doxycycline,
minocycline, tetracycline, chlorotetracycline, oxytetracycline;
aminoglycosides such as gentamicin, neomycin, streptomycin,
tobramycin, amikasin, netilmicin, paromomycin, framycetin, and
spectinomycin; makrolide antibiotics such as azithromycin,
clarithromycin, erythromycin, roxithromycin, spiramycin, and
josamycin; lincosamides such as clindamycin and lincomycin; gyrase
inhibitors, such as fluoroquinolones, which include ciprofloxacin,
ofloxacin, moxifloxacin, norfloxacin, gatifloxacin, enoxacin,
fleroxacin, and levofloxacin; quinolones such as pipemidic acid;
sulphonamides such as trimethoprim, sulphadiazin, and sulphalene;
glycopeptide antibiotics such as vancomycin and teicoplanin;
polypeptide antibiotics, such as polymyxins, which include
colistin, polymyxin-b, and nitroimidazol derivatives (e.g.,
metronidazol and tinidazol); aminoquinolones such as chloroquin,
mefloquin, and hydroxychloroquin; biguanides such as proguanil;
quinine alkaloids and diaminopyrimidines such as pyrimethamine;
amphenicols such as chloramphenicol; rifabutin, dapsone, fusidinic
acid, fosfomycin, nifuratel, telithromycin, fusafungin, fosfomycin,
pentamidindiisethionate, rifampicin, taurolidine, atovaquone, and
linezolid; virostatics such as aciclovir, ganciclovir, famciclovir,
foscamet, inosine (dimepranol-4-acetamidobenzoate), valganciclovir,
valaciclovir, cidofovir, and brivudin; tyrosine kinase inhibitors;
anti-apoptotic agents such as caspase inhibitors (e.g.,
fluoromethylketone peptide derivatives), calpain inhibitors,
cathepsin inhibitors, nitric oxide synthase inhibitors, flavonoids,
vitamin A, vitamin C, vitamin E, vitamin D, pycnogenol, super
oxidedismutase, N-acetyl cysteine, selenium, catechins, alpha
lipoic acid, melatonin, glutathione, zinc chelators, calcium
chelators, and L-arginine; warfarin; beta-blockers; diuretics;
spirolactone; and natural products such as vinca alkaloids (e.g.,
vinblastine, vincristine and vinorelbine).
[0051] As noted above, the therapeutic agent may also include a
biological agent. The biological agent may include organic
substances such as peptides, proteins, enzymes, carbohydrates
(e.g., monosaccharides, oligosaccharides and polysacchardies),
lipids, phospholipids, steroids, lipoproteins, glycoproteins,
glycolipids, proteoglycans, polynucleotides (e.g., DNA and RNA),
antisense polynucleotides (e.g., c-myc antisense), antibodies
(e.g., monoclonal or polycolonal) and/or antibody fragments (e.g.,
anti-CD34 antibody), bioabsorbable polymers (e.g., polylactonic
acid), chitosan, extracellular matrix modulators, such as matrix
metalloproteinases (MMP), which include MMP-2, MMP-9 and
Batimastat; and protease inhibitors.
[0052] Biological agents may include, for example, agents capable
of stimulating angiogenesis in the myocardium. Such agents may
include vascular endothelial growth factor (VEGF), basic fibroblast
growth factor (bFGF), non-viral DNA, viral DNA, and endothelial
growth factors (e.g., FGF-1, FGF-2, VEGF, TGF). Other growth
factors may include erythropoietin and/or various hormones such as
corticotropins, gonadotropins, sonlatropin, thyrotrophin,
desmopressin, terlipressin, oxytocin, cetrorelix, corticorelin,
leuprorelin, triptorelin, gonadorelin, ganirelix, buserelin,
nafarelin, and goserelin. Additional growth factors may also
include cytokines, epidermal growth factors (EGF), platelet derived
growth factor (PDGF), transforming growth factors-.beta.
(TGF-.beta.), transforming growth factor-.alpha. (TGF-.alpha.),
insulin-like growth factor-I (IGF-I), insulin-like growth factor-II
(IGF-II), interleukin-1 (IL-1), interleukin-2 (IL-2), interleukin-6
(IL-6), interleukin-8 (IL-8), tumour necrosis factor-.alpha.
(TNF-.alpha.), tumour necrosis factor-.beta. (TNF-.beta.),
interferon-.gamma. (INF-.gamma.), colony stimulating factors
(CSFs); monocyte chemotactic protein, and fibroblast stimulating
factor 1.
[0053] Still other biological agents may include regulatory
peptides such as somatostatin and octreotide; bisphosphonates
(e.g., risedronates, pamidronates, ibandronates, zoledronic acid,
clodronic acid, etidronic acid, alendronic acid, and tiludronic
acid); fluorides such as disodium fluorophosphate and sodium
fluoride; calcitonin and dihydrotachystyrene; histamine; fibrin or
fibrinogen; endothelin-1; angiotensin II; collagens; bromocriptin;
methylsergide; methotrexate; carbontetrachloride and
thioacetamide.
[0054] The present invention may also be treated (i.e., seeded)
with other biological agents, such as cells. Suitable cells may
include any one or combination of eukaryotic cells. Additionally or
optionally, the cells may be capable of producing therapeutic
agents and/or genetically engineered to produce therapeutic agents.
Suitable cells for use in the present invention include, for
example, progentior cells such as adult stem cells, embryonic stem
cells, and umbilical cord blood stem cells. The cells may be
autologous or allogenic, genetically engineered or non-engineered,
and may include, for example, mesenchymal or mesodermal cells,
including, but not limited to, endothelial progenitor cells,
endothelial cells, and fibroblasts. Mixtures of such cells can also
be used.
[0055] A variety of ex vivo or in vivo methods can be used to
deliver a nucleic acid molecule or molecules, such as a gene or
genes, to the cells. For example, the cells can be modified (i.e.,
genetically engineered) to produce or secrete any one or
combination of the aforementioned therapeutic agents, including,
but not limited to, anticoagulant agents, antiplatelet agents,
antifibrinolytic agents, angiogenesis factors, and the like. Ex
vivo gene transfer is a process by which cells are removed from the
body using well known techniques, genetically manipulated, usually
through transduction or transfection of a nucleic acid molecule
into the cells in vitro, and the returned to the body for
therapeutic purposes. This contrasts with in vivo genetic
engineering where a gene transfer vector is administered to a
patient resulting in genetic transfer into cells and tissues in the
intact patient. Ex vivo and in vivo gene transfer techniques are
well known to one of skill in the art.
[0056] To treat the present invention with at least one therapeutic
agent, a variety of methods, agents, and compositions may be used.
For example, the therapeutic agent can be simply linked to the
stent surface, embedded and released from within polymer materials,
such as a polymer matrix, or surrounded by and released through a
carrier. Several approaches to treating medical devices with
therapeutic agents exist. Some therapeutic agents can be loaded
directly onto metallic surfaces; however, a coating composition,
typically comprised of at least one polymer and at least one
therapeutic agent, is usually used to treat drug-eluting devices.
The coating composition ensures retention of the therapeutic agent
during deployment and modulates elution kinetics of the therapeutic
agent. By altering the release kinetics of different therapeutic
agents in the same coating composition, distinct phases of a given
disease process may be targeted.
[0057] The present invention may be treated with a coating
composition comprising at least one therapeutic agent and at least
one polymer or oligomer material. The polymer(s) and/or oligomer(s)
may be of various types and from various sources, including natural
or synthetic polymers, which are biocompatible, biodegradable,
bioabsorbable and useful for controlled release of the therapeutic
agent. For example, synthetic polymers can include polyesters, such
as polylactic acid, polyglycolic acid, and/or combinations thereof,
polyanhydrides, polycaprolactones, polyhydroxybutyrate valerates,
and other biodegradable polymers or mixtures of copolymers thereof.
Natural polymeric materials can include proteins such as collagen,
fibrin, elastin, extracellular matrix components, other biologic
agents, and/or mixtures thereof.
[0058] The polymer material or mixture thereof of the coating
composition can be applied with the therapeutic agent on the
surface of the present invention and can comprise a single layer.
Optionally, multiple layers of the polymer material can be applied
to form the coating composition. Multiple layers of the polymer
material can also be applied between layers of the therapeutic
agent. For example, the polymeric layers may be applied
sequentially, with the first layer directly in contact with the
uncoated surface of the apparatus and a second layer comprising the
therapeutic agent and having one surface in contact with the first
layer and the opposite surface in contact with a third layer of
polymeric material which is in contact with the surrounding tissue.
Additional layers of the polymeric material and therapeutic agent
can be added as required.
[0059] Alternatively, the coating composition can be applied as
multiple layers comprising one or more therapeutic agents
surrounded by polymer material. For instance, the coating
composition can comprise multiple layers of a single therapeutic
agent, one or more therapeutic agents in each layer, and/or
differing therapeutic agents in alternating layers. Alternatively,
the layers comprising the therapeutic agent can be separated from
one another by a layer of polymer material.
[0060] The coating composition may further comprise at least one
pharmaceutically acceptable polymers and/or pharmaceutically
acceptable carriers, for example, non-absorbable polymers, such as
ethylene vinyl acetate and methylmethacrylate. The non-absorbable
polymer, for example, can aid in further controlling release of the
therapeutic agent by increasing the molecular weight of the coating
composition and thereby delaying or slowing the rate of release of
the therapeutic agent.
[0061] The coating composition can be applied to the present
invention using standard techniques to cover the entire surface of
the apparatus, or partially, as a single layer in a dot matrix
pattern, for example. The coating composition can be applied using
various techniques available in the art, such as dipping, spraying,
vapor deposition, an injection-like and/or a dot matrix-like
approach. Upon contact of the coating composition with adjacent
tissue where implanted, the coating composition can begin to
degrade in a controlled manner. As the coating composition
degrades, the therapeutic agent is slowly released into adjacent
tissue and the therapeutic agent is eluted so that the therapeutic
agent can have its effect locally.
[0062] Where the therapeutic agent comprises a biological agent,
such as cells, the biological agent can be coated directly onto the
surface of the present invention or, alternatively, they can be
incorporated into the polymeric material (e.g., into a polymer
matrix). Such biological agents may also be included within at
least one microscopic containment vehicle (e.g., a liposome,
nanocapsule, nanoparticle, micelle, synthetic phospholipid,
gas-dispersion, emulsion, microemulsion, nanosphere, and the like)
that can be stimulated to release the biological agent(s) and/or
that release the biological agent(s) in a controlled manner. The
microscopic containment vehicle can be coated onto the surface of
the present invention or incorporated into the polymeric material.
Where the biological agent comprises cells, for example, the cells
can be induced to produce, activate, and/or release their cellular
products (including one or more therapeutic agents) by an external
stimulation device (e.g., an electrical impulse). Alternatively,
cells can constitutively release one or more therapeutic agents at
a desired level.
[0063] To enable delivery and deployment of the apparatus 10, the
apparatus is positioned about a balloon 120 (FIG. 1) for expanding
the main body portion 46 of the support member 40 into full and
complete contact with the annulus 20 of the mitral valve 14. The
balloon 120 may have an hourglass shape to conform to the concave
cross-sectional configuration of the main body portion 46. The
shape of the balloon 120 is defined by first and second bulb
sections 122 and 124 connected by a center section 126. Each of
these sections 122, 124 and 126 may have a D-shaped diameter (or
other shaped diameter) to match the D-shaped diameter of the valve
14 and the prosthetic valve 12. The center section 126 of the
balloon 120 has a smaller diameter than the bulb sections 122 and
124. The first and second bulb sections 122 and 124 and the center
section 126 may be inflated together or separately. Further, the
sections 122, 124 and 126 may have multiple chambers to accommodate
multiple fluids (i.e., an inflation fluid and a cooling fluid).
[0064] In addition, releasable constraining wires (not shown) are
used to temporarily hold the upper wing members 60 and the lower
wing members 70 in the radially collapsed conditions shown in FIG.
1 during delivery and placement of the apparatus 10. The
constraining wires can be made from a variety of different
materials including metals, polymers, synthetics, fabrics, and
biological tissues. With the upper wing members 60, the lower wing
members 70, and the main body portion 46 of the support member 40
in their collapsed conditions, the apparatus 10 is then loaded into
the end of a 16 to 22 French catheter 128 in a known manner.
[0065] To replace the mitral valve 14 with the apparatus 10 using a
percutaneous (or intravascular) approach, the apparatus is first
sized for the particular mitral valve using fluoroscopic and/or
echocardiographic data. The catheter 128 is then introduced into
either the right or left jugular vein (not shown), a femoral vein
(not shown), or the subclavian vein (not shown) using a known
percutaneous technique, such as the Seldinger technique, and is
advanced through the superior or inferior vena cava (not shown) to
approach the right atrium (not shown). The catheter 128 is passed
through the interatrial septum (not shown) to reach the left atrium
16. From inside the left atrium 16, the apparatus 10 is then
positioned within the annulus 20 of the mitral valve 14 as is shown
in FIG. 1. It should be noted that the angular orientation of the
apparatus 10 within the mitral valve 14 is important, so a
diagnostic agent or agents, such as radiopaque markers (not shown),
may be used to ensure the apparatus is rotated to the proper
position prior to deployment.
[0066] Next, the catheter 128 is pulled back so that the support
member 40 can expand to the condition shown in FIG. 2 in the
annulus 20 of the native mitral valve 14. The balloon 120 is then
inflated, which pushes the main body portion 46 of the support
member 40 into engagement with the annulus 20 as shown in FIG.
5.
[0067] The constraining wires are then released, which allows the
upper wing members 60 and the lower wing members 70 of the support
member 40 to spring radially outward toward their expanded
conditions illustrated in FIGS. 2-8. The upper wing members 60, in
their radially extended condition, extend transverse to the
direction of blood flow through the prosthetic valve 12, and engage
the wall of the left atrium 16. Where the attachment mechanism 62
comprises barbs 64 as shown in FIG. 5, the barbs embed into the
wall of the left atrium 16 to help secure the support member 40 in
the annulus 20 of the mitral valve 14.
[0068] As the lower wing members 70 move from their radially
collapsed condition to their radially extended condition, each of
the lower wing members engages a portion of the native valve
leaflets 22 and 24. The first and second lower wing members 72 and
74 engage the commissures of the native mitral valve 14 (FIG. 5),
while the third and fourth lower wing members 76 and 78 engage
respective central portions of the native valve leaflets 22 and 24
(FIG. 6). The barbs 64 on the lower wing members 70 embed into the
native valve leaflets 22 and 24 to help secure the support member
40 in the annulus 20 of the mitral valve 14. In their radially
extended condition, the lower wing members 70 pin the native
leaflets 22 and 24 back against the valve annulus 20 so that the
prosthetic valve 12 can assume the valvular function. With the
apparatus 10 fully deployed, the balloon 120 is deflated and moved
out of the valve annulus 20.
[0069] It should be noted that the engagement of the main body
portion body 46 with the valve annulus 20, the engagement of the
upper wing members 60 with the wall of the left atrium 16, and the
engagement of the lower wing members 70 that pins the native valve
leaflets 22 and 24 back against the valve annulus provides a unique
three-way locking mechanism for securing the apparatus 10 in the
valve annulus.
[0070] It is contemplated that the apparatus 10 according to the
present invention could alternatively be placed by a retrograde,
percutaneous approach. For example, the apparatus 10 may be urged
in a retrograde fashion through a femoral artery (not shown),
across the aortic arch (not shown), through the aortic valve (not
shown), and into the left ventricle 18 where the apparatus may then
be appropriate positioned in the native mitral valve 14.
[0071] FIG. 12 illustrates another alternative embodiment of the
present invention. The apparatus 10.sub.b of FIG. 12 is identically
constructed as the apparatus 10 of FIGS. 2-8, except whereas
described below. In FIG. 12, structures that are identical as
structures in FIGS. 2-8 use the same reference numbers, whereas
structures that are similar but not identical carry the suffix
"b".
[0072] As shown in FIG. 12, the apparatus 10.sub.b comprises a
tri-leaflet prosthetic valve 12.sub.b. Examples of tri-leaflet
prosthetic valves, such as the prosthetic valves disclosed in U.S.
Pat. No. 5,156,621, which is hereby incorporated by reference in
its entirety, are known in the art. The tri-leaflet prosthetic
valve 12.sub.b, such as a porcine aortic valve, may be used in
either the mitral or tricuspid position. The prosthetic valve
12.sub.b may be made of other biological materials, including, but
not limited to, aortic xenografts, bovine pericardial tissue,
equine pericardial tissue, porcine pericardial tissue, peritoneal
tissue, and a homograft or allograft. Additionally, the prosthetic
valve 12.sub.b may be made of any one or combination of
biocompatible materials such as polyurethane, PTFE, expanded PTFE,
Dacron.RTM., woven velour, Gore-Tex.RTM., and heparin coated
fabric.
[0073] As may be seen in FIG. 12, in the tricuspid position, six
lower wing members 70 may be used so that a lower wing member is
positioned at each native commissure and directly over each native
valve leaflet. The support structure 40 of the apparatus 10.sub.b
also includes at least three strut members 45 that are spaced apart
from each other. The valve leaflets of the prosthetic valve
12.sub.b are joined together at at least three commissural sections
47. Each of the three commissural sections 47 are attached to a
representative one of the strut members 45 to prevent prolapse of
the valve leaflets 22 and 24. Other than this, the apparatus
10.sub.b with the tri-leaflet prosthetic valve 12.sub.b is deployed
and functions as described above with regard to the previous
embodiment. It should be understood that more or less than six
lower wing members 70 could be used.
[0074] The present invention thus allows for the apparatus 10 to be
delivered in a cardiac catheterization laboratory with a
percutaneous approach under local anesthesia using fluoroscopic as
well as echocardiographic guidance, thereby avoiding general
anesthesia and highly invasive open heart surgery techniques. This
approach offers tremendous advantages for high risk patients with
severe valvular disease. It should be understood, however, that the
present invention contemplates. various other approaches, including
standard open heart surgeries as well as minimally invasive
surgical techniques. Because the present invention omits stitching
of the apparatus 10 in the valve annulus 20, surgical time is
reduced regardless of whether an open, minimally invasive or
percutaneous approach is used.
[0075] From the above description of the invention, those skilled
in the art will perceive improvements, changes and modifications.
For example, it should be understood by those skilled in the art
that the various portions of the support member 40 could be
self-expanding or expanded by a change in temperature (because they
are made from a shape memory material). Such improvements, changes
and modifications within the skill of the art are intended to be
covered by the appended claims.
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