U.S. patent application number 11/451354 was filed with the patent office on 2007-03-01 for devices and methods for heart valve treatment.
This patent application is currently assigned to Myocor, Inc.. Invention is credited to Jason E. Kalgreen, David Kusz, Todd J. Mortier, Richard Schroeder, Cyril J. JR. Schweich, Robert M. Vidlund.
Application Number | 20070050022 11/451354 |
Document ID | / |
Family ID | 21912921 |
Filed Date | 2007-03-01 |
United States Patent
Application |
20070050022 |
Kind Code |
A1 |
Vidlund; Robert M. ; et
al. |
March 1, 2007 |
Devices and methods for heart valve treatment
Abstract
Devices and methods for treating heart valves include members
that assist the valve in closing during at least a portion of the
cardiac cycle. Such devices include members configured to alter the
shape of a valve annulus, reposition at least one papillary muscle,
and/or plug an orifice of the valve so as to provide a coaptation
surface for the valve leaflets.
Inventors: |
Vidlund; Robert M.;
(Maplewood, MN) ; Kalgreen; Jason E.; (Plymouth,
MN) ; Mortier; Todd J.; (Minneapolis, MN) ;
Schweich; Cyril J. JR.; (Maple Grove, MN) ;
Schroeder; Richard; (Fridley, MN) ; Kusz; David;
(Minneapolis, MN) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Myocor, Inc.
|
Family ID: |
21912921 |
Appl. No.: |
11/451354 |
Filed: |
June 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10866990 |
Jun 15, 2004 |
7077862 |
|
|
11451354 |
Jun 13, 2006 |
|
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10040784 |
Jan 9, 2002 |
6764510 |
|
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10866990 |
Jun 15, 2004 |
|
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Current U.S.
Class: |
623/2.37 |
Current CPC
Class: |
A61F 2/2481 20130101;
A61B 2017/00243 20130101; A61B 17/00234 20130101; A61B 2017/0496
20130101; A61F 2/246 20130101; A61B 17/0401 20130101; A61B
2017/06052 20130101; A61F 2/2487 20130101; A61F 2/2445 20130101;
A61F 2/2451 20130101; A61B 17/0487 20130101; A61F 2/2454 20130101;
A61B 2017/0417 20130101; A61B 2017/0464 20130101 |
Class at
Publication: |
623/002.37 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A method for treating a heart valve, comprising: providing a
device having an arcuate portion and at least one elongate portion
configured to extend from the arcuate portion; encircling at least
a portion of an annulus of a heart valve with the arcuate portion;
adjusting a size of at least one of the arcuate portion and the
elongate portion so as to alter a shape of the portion of the
annulus; and securing the at least one elongate portion to an
exterior surface of the heart.
2-124. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to devices and related methods
for treating and improving the function of dysfunctional heart
valves. More particularly, the invention relates to devices and
related methods that passively assist to close a heart valve to
improve valve function of poorly functioning valves.
[0003] 2. Description of the Related Art
[0004] Various etiologies may result in heart valve insufficiency
depending upon both the particular valve as well as the underlying
disease state of the patient. For instance, a congenital defect may
be present resulting in poor coaptation of the valve leaflets, such
as in the case of a monocusp aortic valve, for example. Valve
insufficiency also may result from an infection, such as rheumatic
fever, for example, which may cause a degradation of the valve
leaflets. Functional regurgitation also may be present. In such
cases, the valve components may be normal pathologically, yet may
be unable to function properly due to changes in the surrounding
environment. Examples of such changes include geometric alterations
of one or more heart chambers and/or decreases in myocardial
contractility. In any case, the resultant volume overload that
exists as a result of an insufficient valve may increase chamber
wall stress. Such an increase in stress may eventually result in a
dilatory process that further exacerbates valve dysfunction and
degrades cardiac efficiency.
[0005] Mitral valve regurgitation often may be driven by the
functional changes described above. Alterations in the geometric
relationship between valvular components may occur for numerous
reasons, including events ranging from focal myocardial infarction
to global ischemia of the myocardial tissue. Idiopathic dilated
cardiomyopathy also may drive the evolution of functional mitral
regurgitation. These disease states often lead to dilatation of the
left ventricle. Such dilatation may cause papillary muscle
displacement and/or dilatation of the valve annulus. As the
papillary muscles move away from the valve annulus, the chordae
connecting the muscles to the leaflets may become tethered. Such
tethering may restrict the leaflets from closing together, either
symmetrically or asymmetrically, depending on the relative degree
of displacement between the papillary muscles. Moreover, as the
annulus dilates in response to chamber enlargement and increased
wall stress, increases in annular area and changes in annular shape
may increase the degree of valve insufficiency. Annular dilatation
is typically concentrated on the posterior aspect, since this
aspect is directly associated with the expanding left ventricular
free wall and not directly attached to the fibrous skeleton of the
heart. Annular dilatation also may result in a flattening of the
valve annulus from its normal saddle shape.
[0006] Alterations in functional capacity also may cause valve
insufficiency. In a normally functioning heart, the mitral valve
annulus contracts during systole to assist in leaflet coaptation.
Reductions in annular contractility commonly observed in ischemic
or idiopathic cardiomyopathy patients therefore hamper the closure
of the valve. Further, in a normal heart, the papillary muscles
contract during the heart cycle to assist in maintaining proper
valve function. Reductions in or failure of the papillary muscle
function also may contribute to valve regurgitation. This may be
caused by infarction at or near the papillary muscle, ischemia, or
other causes, such as idiopathic dilated cardiomyopathy, for
example.
[0007] The degree of valve regurgitation may vary, especially in
the case of functional insufficiency. In earlier stages of the
disease, the valve may be able to compensate for geometric and/or
functional changes in a resting state. However, under higher
loading resulting from an increase in output requirement, the valve
may become incompetent. Such incompetence may only appear during
intense exercise, or alternatively may be induced by far less of an
exertion, such as walking up a flight of stairs, for example.
[0008] Conventional techniques for managing mitral valve
dysfunction include either surgical repair or replacement of the
valve or medical management of the patient. Medical management
typically applies only to early stages of mitral valve dysfunction,
during which levels of regurgitation are relatively low. Such
medical management tends to focus on volume reductions, such as
diuresis, for example, or afterload reducers, such as vasodilators,
for example.
[0009] Early attempts to surgically treat mitral valve dysfunction
focused on replacement technologies. In many of these cases, the
importance of preserving the native subvalvular apparatus was not
fully appreciated and many patients often acquired ventricular
dysfunction or failure following the surgery. Though later
experience was more successful, significant limitations to valve
replacement still exist. For instance, in the case of mechanical
prostheses, lifelong therapy with powerful anticoagulants may be
required to mitigate the thromboembolic potential of these devices.
In the case of biologically derived devices, in particular those
used as mitral valve replacements, the long-term durability may be
limited. Mineralization induced valve failure is common within ten
years, even in older patients. Thus, the use of such devices in
younger patient groups is impractical.
[0010] Another commonly employed repair technique involves the use
of annuloplasty rings. These rings originally were used to
stabilize a complex valve repair. Now, they are more often used
alone to improve mitral valve function. An annuloplasty ring has a
diameter that is less than the diameter of the enlarged valve
annulus. The ring is placed in the valve annulus and the tissue of
the annulus sewn or otherwise secured to the ring. This causes a
reduction in the annular circumference and an increase in the
leaflet coaptation area. Such rings, however, generally flatten the
natural saddle shape of the valve and hinder the natural
contractility of the valve annulus. This may be true even when the
rings have relatively high flexibility.
[0011] To further reduce the limitations of the therapies described
above, purely surgical techniques for treating valve dysfunction
have evolved. Among these surgical techniques is the Alfiere stitch
or so-called bowtie repair. In this surgery, a suture is placed
substantially centrally across the valve orifice between the
posterior and anterior leaflets to create leaflet apposition.
Another surgical technique includes plication of the posterior
annular space to reduce the cross-sectional area of the valve
annulus. A limitation of each of these techniques is that they
typically require opening the heart to gain direct access to the
valve and the valve annulus. This generally necessitates the use of
cardiopulmonary bypass, which may introduce additional morbidity
and mortality to the surgical procedures. Additionally, for each of
these procedures, it is very difficult, if not impossible, to
evaluate the efficacy of the repair prior to the conclusion of the
operation.
[0012] Due to these drawbacks, devising effective techniques that
could improve valve function without the need for cardiopulmonary
bypass and without requiring major remodeling of the valve may be
advantageous. In particular, passive techniques to change the shape
of the heart chamber and associated valve and/or reduce
regurgitation while maintaining substantially normal leaflet motion
may be desirable. Further, advantages may be obtained by a
technique that reduces the overall time a patient is in surgery and
under the influence of anesthesia. It also may be desirable to
provide a technique for treating valve insufficiency that reduces
the risk of bleeding associated with anticoagulation requirements
of cardiopulmonary bypass. In addition, a technique that can be
employed on a beating heart would allow the practitioner an
opportunity to assess the efficacy of the treatment and potentially
address any inadequacies without the need for additional bypass
support.
SUMMARY OF THE INVENTION
[0013] A recently developed passive technique that addresses at
least some of the drawbacks discussed above includes applying
passive devices to the heart, for example the left ventricle, to
change the shape of the ventricle and concomitantly to improve
coaptation of the mitral valve leaflets. In one embodiment, the
technique involves implanting splints across the left ventricle.
Examples of various splinting approaches are disclosed in U.S.
application Ser. No. 09/680,435, filed Oct. 6, 2000, entitled
"Methods and Devices for the Improvement of Mitral Valve Function,"
which is assigned to the same assignee as the present application
and which is incorporated by reference in its entirety herein.
[0014] The devices and related methods which will be disclosed
herein also operate passively to treat valve insufficiency, by
altering the shape of the valve annulus and/or repositioning the
papillary muscles, for example. Some of the devices of the present
invention may be used in combination with the splinting treatments
disclosed in U.S. application Ser. No. 09/680,435, incorporated by
reference herein.
[0015] It should be understood that the invention disclosed herein
could be practiced without performing one or more of the objects
and/or advantages described above. Other aspects will become
apparent from the detailed description which follows. As embodied
and broadly described herein, the invention includes a method for
treating a heart valve comprising providing a device having an
arcuate portion and at least one elongate portion configured to
extend from the arcuate portion. The method may further comprise
encircling at least a portion of an annulus of a heart valve with
the arcuate portion and adjusting a size of at least one of the
arcuate portion and the elongate portion so as to alter a shape of
the portion of the annulus. The method also may include securing
the at least one elongate portion to an exterior surface of the
heart.
[0016] According to another aspect, a method of treating a heart
valve comprises providing a device having an arcuate portion and at
least one elongate member configured to extend from the arcuate
portion. The method further comprises placing the arcuate portion
proximate an annulus of a heart valve and extending the at least
one elongate member from the arcuate portion. The method also may
comprise securing the at least one elongate member to an exterior
surface of the heart, wherein the at least one elongate member
extends from the arcuate portion to the heart wall in substantially
the same plane as the arcuate portion.
[0017] Yet another aspect includes a device for treating a heart
valve comprising an arcuate portion configured to at least partly
encircle an annulus of the heart valve and at least one elongate
portion extending from the arcuate portion and configured to be
secured to an exterior surface of a heart wall surrounding a heart
chamber associated with the valve. At least one of the arcuate
portion and the elongate portion is configured to be adjusted in
size so as to alter a shape of at least a portion of the
annulus.
[0018] In yet another aspect, a device for treating a heart valve
comprises an arcuate portion configured to be positioned proximate
an annulus of the heart valve and at least one elongate member
extending from the arcuate portion and configured to be secured to
an exterior surface of the heart wall. The at least one elongate
member extends from the arcuate portion to the heart wall in
substantially the same plane as the arcuate portion.
[0019] According to yet another aspect, the invention includes a
device for treating a heart valve comprising at least one
substantially elongate member configured to be implanted in a lumen
of a coronary vessel so as to encircle at least a portion of an
annulus of the heart valve and alter a shape of at least the
portion of the annulus. The device may further comprise a shape
change element associated with the elongate member and configured
to impart a local shape change to a portion of the valve annulus at
a location corresponding to the shape change element.
[0020] Yet another aspect includes a device for treating a heart
valve comprising at least one substantially elongate member
configured to be implanted in a lumen of a coronary vessel so as to
encircle at least a portion of an annulus of the heart valve and
alter a shape of at least the portion of the valve annulus. The
shape of at least a portion of the elongate member may be
configured to be adjustable so as to impart a local shape change to
a portion of the valve annulus at a location corresponding to at
least the adjustable portion.
[0021] Yet another aspect of the invention includes a method for
treating a heart valve comprising providing at least one
substantially elongate member and extending at least a portion of
the elongate member within a heart wall surrounding a chamber of
the heart associated with the heart valve so as to encircle at
least a portion of the heart chamber. The method may further
comprise securing the elongate member in place with respect to the
heart and compressing at least a portion of a heart wall
surrounding at least the portion of the heart chamber so as to move
leaflets of the valve toward each other so as to assist the valve
in closing during at least a portion of the cardiac cycle.
[0022] In yet another aspect, a method for treating a heart valve
comprises providing at least one substantially elongate member and
extending at least a portion of the elongate member within a lumen
of a coronary sinus so as to encircle at least a portion of a heart
chamber. The method further comprises securing the elongate member
in place with respect to the heart via securement mechanisms and
compressing at least a portion of a heart wall surrounding the
portion of the heart chamber so as to move leaflets of the valve
toward each other so as to assist the valve in closing during at
least a portion of the cardiac cycle.
[0023] Yet another aspect of the invention includes a device for
treating a heart valve comprising an elongate member having first
and second oppositely disposed ends, with the elongate member being
relatively rigid, a first anchoring member configured to be
attached to the first end of the elongate member, and a second
anchoring member configured to be attached to the second end of the
elongate member. The first anchoring member may be configured to
engage a first exterior surface of a wall of the heart and the
second anchoring member may be configured to engage a second
exterior surface of the wall of the heart to maintain a position of
the elongate member transverse a heart chamber associated with the
valve and substantially along a line of coaptation of the valve.
The length of the elongate member may be such that the elongate
member is capable of maintaining a substantially normal distance
between trigones of the valve.
[0024] In yet another aspect, a method for treating a heart valve
comprises providing a relatively rigid elongate member having first
and second oppositely disposed ends, securing the first end of the
elongate member to a first exterior heart wall surface, and
securing the second end of the elongate member to a second exterior
heart wall surface, the second exterior surface being located
substantially opposite to the first exterior surface such that the
elongate member extends substantially transverse a heart chamber
associated with the valve and substantially along a line of
coaptation of the valve. The method also may comprise maintaining a
substantially normal distance between the trigones of the valve via
the elongate member.
[0025] Yet another aspect of the invention includes a device for
treating leakage of a heart valve comprising an expandable plug
member having an external surface, with at least a portion of the
plug member being configured to be positioned proximate leaflets of
the heart valve. The device also may comprise a securement
mechanism attached to the plug member and configured to secure the
plug member with respect to the heart such that during at least a
portion of the cardiac cycle, the leaflets abut the external
surface of the plug member to restrict bloodflow through the
valve.
[0026] According to another aspect, a device for treating leakage
of a heart valve comprises a plug member having a piston-like
configuration and an external surface being configured to abut free
ends of leaflets of the valve to restrict bloodflow through the
valve during at least the portion of the cardiac cycle. The device
may further comprise a securement mechanism attached to the plug
member and configured to secure the plug member with respect to the
heart.
[0027] Yet another aspect of the invention includes a method of
preventing leakage in a heart valve comprising providing an
expandable plug member having an external surface, delivering the
plug member to a heart chamber containing a valve, and positioning
the plug member proximate leaflets of the valve such that the
leaflets contact the external surface of the plug member during at
least a portion of the cardiac cycle so as to restrict bloodflow
through the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate several
embodiments of the invention and together with the description,
serve to explain certain principles. In the drawings,
[0029] FIG. 1a is a short-axis cross-sectional view of the
heart;
[0030] FIG. 1b is a partial short axis cross-sectional view of the
heart;
[0031] FIG. 2a is a top view of a properly functioning mitral valve
in an open position;
[0032] FIG. 2b is a top view of a properly functioning mitral valve
in a closed position;
[0033] FIG. 2c is a top view of an improperly functioning mitral
valve in a "closed" position;
[0034] FIG. 3a is a side view of a properly functioning mitral
valve shown with its connection to the papillary muscles;
[0035] FIG. 3b is a side view of an improperly functioning mitral
valve shown with its connection to the papillary muscles;
[0036] FIG. 4a is a cross-sectional view of a mitral valve and a
coronary sinus with an exemplary embodiment of a curved frame
member implanted in the coronary sinus according to an aspect of
the invention;
[0037] FIG. 4b is a cross-sectional view of another exemplary
embodiment of a curved frame member implanted in a coronary sinus
according to an aspect of the invention;
[0038] FIG. 4c is a perspective view of yet another exemplary
embodiment of a curved frame member implanted in a coronary sinus
according to an aspect of the invention;
[0039] FIG. 4d is a perspective view of yet another exemplary
embodiment of a curved frame member for implantation in a coronary
sinus according to an optional aspect of the invention;
[0040] FIG. 4e is a perspective view of yet another exemplary
embodiment of a curved frame member for implantation in a coronary
sinus according to an aspect of the invention;
[0041] FIG. 4f is a perspective view of yet another embodiment of a
curved frame member for implantation in a coronary sinus according
to an aspect of the invention;
[0042] FIG. 4g is a perspective view of the curved frame member of
FIG. 4f in a curved configuration;
[0043] FIG. 4h is a perspective view of yet another exemplary
embodiment of a curved frame member according to an aspect of the
invention;
[0044] FIG. 4i is a perspective view of the curved frame member of
FIG. 4h in a curved configuration;
[0045] FIG. 5a is a long axis, partial, cross-sectional view of a
heart with a snare device delivered to the mitral valve according
to an exemplary embodiment of the invention;
[0046] FIG. 5b is a short axis, cross-sectional view of a heart
with filaments delivered to the mitral valve and captured by the
snare device of FIG. 5a according to an exemplary embodiment of the
invention;
[0047] FIG. 5c is a long axis, partial, cross-sectional view of a
heart with the filaments of FIG. 5b drawn through the left atrium
by the snare device according to an exemplary embodiment of the
invention;
[0048] FIG. 5d is a short axis, cross-sectional view of a heart
showing an embodiment of a floating ring device implanted to treat
the mitral valve according to an optional aspect of the
invention;
[0049] FIG. 5e is a perspective view of an exemplary embodiment of
a floating ring device according to an aspect of the invention;
[0050] FIG. 6a is a short axis cross-sectional view of a heart
showing an exemplary embodiment of an annular noose implanted to
treat the mitral valve according to an aspect of the invention;
[0051] FIG. 6b is a cross-sectional view of a mitral valve with
another exemplary embodiment of an annular noose implanted to treat
the mitral valve according to an aspect of the invention;
[0052] FIG. 6c is a cross-sectional view of a mitral valve with yet
another exemplary embodiment of an annular noose implanted to treat
the mitral valve according to an aspect of the invention;
[0053] FIG. 6d is a short axis cross-sectional view of a heart with
another exemplary embodiment of an annular noose implanted to treat
the mitral valve according to an aspect of the invention;
[0054] FIG. 6e is a short axis cross-sectional view of a heart with
another exemplary embodiment of an annular noose according to an
aspect of the invention;
[0055] FIG. 7a is a short axis, cross-sectional view of a heart
showing an exemplary embodiment of an elongate bar and a snare
device around the elongate bar implanted to treat the mitral valve
according to an aspect of the invention;
[0056] FIG. 7b is a short axis, cross-sectional view of a heart
showing an embodiment of an internal strut device implanted to
treat the mitral valve according to an optional aspect of the
present invention;
[0057] FIG. 8 is a short axis, cross-sectional view of a heart
implanted with an exemplary embodiment of an intrawall splint
according to an aspect of the invention;
[0058] FIG. 9 is a partial perspective view of a heart implanted
with an exemplary embodiment of an external plication device
according to an aspect of the invention;
[0059] FIG. 10a is a schematic side view of an improperly
functioning mitral valve during systole;
[0060] FIG. 10b is a schematic side view of the valve of FIG. 10a
with an exemplary embodiment of a plug device implanted in the
valve orifice according to an aspect of the invention;
[0061] FIG. 11a is an exemplary embodiment of a spherical plug
device implanted in the valve orifice between the valve leaflets
according to an aspect of the invention;
[0062] FIG. 11b is an exemplary embodiment of an ellipsoidal plug
device implanted in the valve orifice between the valve leaflets
according to an aspect of the invention;
[0063] FIG. 11c is an exemplary embodiment of a disk-shaped plug
device implanted in the valve orifice between the valve leaflets
according to an aspect of the invention;
[0064] FIG. 11d is an exemplary embodiment of a wing-shaped plug
device implanted in the valve orifice between the valve leaflets
according to an aspect of the invention;
[0065] FIG. 11e is an exemplary embodiment of a sheet-like plug
device implanted in the valve orifice between the valve leaflets
according to an aspect of the invention;
[0066] FIG. 11f is an exemplary embodiment of an inflatable
sheet-like plug device configured to be implanted in the valve
orifice between the valve leaflets according to an aspect of the
invention;
[0067] FIG. 11g(i) is a perspective view of an exemplary embodiment
of collapsible tube plug device in its expanded configuration
according to an aspect of the invention;
[0068] FIG. 11g(ii) is a perspective view of the collapsible tube
plug device of FIG. 11g(i) in its collapsed configuration according
to an aspect of the invention;
[0069] FIG. 11h(i) is another exemplary embodiment of a collapsible
plug device in its expanded configuration implanted in the valve
according to an aspect of the invention;
[0070] FIG. 11h(ii) shows the collapsible plug device of FIG.
11h(i) in its collapsed configuration implanted in the valve
according to an aspect of the invention;
[0071] FIG. 11i(i) is yet another exemplary embodiment of a
collapsible plug device in its expanded configuration implanted in
the valve according to an aspect of the invention;
[0072] FIG. 11i(ii) shows the collapsible plug device of FIG.
11i(i) in its collapsed configuration implanted in the valve
according to an aspect of the invention;
[0073] FIG. 11j(i) is yet another exemplary embodiment of a
collapsible plug device in its expanded configuration implanted in
the valve according to an aspect of the invention;
[0074] FIG. 11j(ii) shows the collapsible plug device of FIG.
11j(i) in its collapsed configuration implanted in the valve
according to an aspect of the invention;
[0075] FIG. 11k is an exemplary embodiment of a piston-like plug
device implanted in the valve according to an aspect of the
invention;
[0076] FIG. 11l(i) is another exemplary embodiment of a piston-like
plug device shown in a collapsed configuration implanted in the
valve according to an aspect of the invention;
[0077] FIG. 11l(ii) shows the piston-like plug device of FIG.
11l(i) shown in an expanded configuration implanted in the valve
according to an aspect of the invention;
[0078] FIG. 11m(i) is yet another exemplary embodiment of a plug
device shown implanted in the heart during systole according to an
aspect of the invention;
[0079] FIG. 11m(ii) shows the plug device of FIG. 11m(i) shown
implanted in the heart during diastole according to an aspect of
the invention;
[0080] FIG. 12 is a partial perspective view of the heart showing a
plug device implanted in the heart according to an optional aspect
of the invention;
[0081] FIG. 13a is a long axis cross-sectional view of the left
ventricle and left atrium of a heart showing schematically various
exemplary positions for a plug device according to an optional
aspect of the invention;
[0082] FIG. 13b is a long axis cross-sectional view of the left
ventricle and left atrium of a heart showing schematically various
exemplary positions for a plug device according to an aspect of the
invention;
[0083] FIG. 13c is a basal cut away cross-sectional view of the
heart showing schematically various exemplary positions for a plug
device according to an aspect of the invention;
[0084] FIG. 13d is a long axis cross-sectional view of the left
ventricle and left atrium of a heart showing schematically an
exemplary position for a plug device according to an aspect of the
invention;
[0085] FIG. 14a is a partial perspective view of the left ventricle
and left atrium of a heart showing an exemplary embodiment of a
needle and stylet assembly for delivering a plug device according
to an aspect of the invention;
[0086] FIG. 14b is a long axis cross-sectional view of the heart
showing the placement of the needle and stylet assembly of FIG. 14a
relative to the mitral valve leaflets according to an aspect of the
invention;
[0087] FIG. 14c is a partial perspective view of the left ventricle
and left atrium with a leader assembly and sheath retaining a plug
device being advanced through the needle of FIG. 14a according to
an aspect of the invention;
[0088] FIG. 14d is a partial perspective view of the left ventricle
and left atrium showing an exemplary embodiment of a sheath
retaining a plug device being advanced through the heart according
to an aspect of the invention;
[0089] FIG. 14e is a partial short axis cross-sectional view of the
heart during systole viewed from the top and showing an exemplary
embodiment of a plug device implanted in the valve according to an
aspect of the invention;
[0090] FIG. 14f is a partial short axis cross-sectional view of the
heart during diastole viewed from the top and showing an exemplary
embodiment of a plug device implanted in the valve according to an
aspect of the invention;
[0091] FIG. 15a is a perspective view of an exemplary embodiment of
a trocar and needle assembly for delivery of a plug device
according to an aspect of the invention;
[0092] FIG. 15b is a perspective view of the trocar and needle
assembly of FIG. 15a with an exemplary embodiment of a pusher
assembly used to advance an anchor of a plug device out of the
trocar and needle assembly according to an aspect of the
invention;
[0093] FIG. 15c is a perspective view of the trocar and needle
assembly of FIG. 15a with an exemplary embodiment of plug member
advanced out of the trocar and needle assembly according to an
aspect of the invention;
[0094] FIG. 16a is a perspective view of an exemplary embodiment of
a plug device with a plug member in a folded configuration
according to an aspect of the invention;
[0095] FIG. 16b is a partial perspective view of a left ventricle
and left atrium with the plug device of FIG. 16a delivered to the
heart in a folded configuration according to an aspect of the
invention;
[0096] FIG. 16c is a partial perspective view of a left ventricle
and left atrium showing an exemplary embodiment for unfolding the
plug member of FIG. 16a according to an aspect of the
invention;
[0097] FIG. 16d is a partial perspective view of a left ventricle
and left atrium showing the plug device of FIG. 16a implanted in
the heart in an unfolded configuration according to an aspect of
the invention;
[0098] FIG. 17a is a cross-sectional view of the heart showing an
exemplary embodiment of an endovascular delivery path for
delivering a plug device according to an aspect of the
invention;
[0099] FIG. 17b is a cross-sectional view of the heart showing
another exemplary embodiment of an endovascular delivery path for
delivering a plug device according to an aspect of the
invention;
[0100] FIG. 17c is a cross-sectional view of the heart showing yet
another exemplary embodiment of an endovascular delivery path for
delivering a plug device according to an aspect of the
invention;
[0101] FIG. 18a is a perspective view of an exemplary embodiment of
a plug device and anchoring frame according to an aspect of the
invention;
[0102] FIG. 18b is a long axis partial cross-sectional view of the
heart showing an exemplary embodiment of the implantation of the
plug device and anchoring frame of FIG. 18a according to an aspect
of the invention;
[0103] FIG. 19 is a long axis partial cross-sectional view of the
heart showing an exemplary embodiment of an inflation device and a
plug device having an inflatable plug member and anchors according
to an aspect of the invention; and
[0104] FIG. 20 is a perspective view of an exemplary embodiment of
an inflatable plug device according to an aspect of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0105] Certain aspects of the invention that will be discussed
herein generally pertain to devices and methods for treating valve
insufficiency arising from heart conditions, including, for
example, ventricle dilatation, valve incompetencies, congenital
defects, and other conditions. The various devices to be described
may operate passively in that, once implanted in the heart, they do
not require an active stimulus, either mechanical, electrical, or
otherwise, to function. Implanting one or more of the devices of
the present invention may assist in closing a valve to prevent
regurgitation by, for example, assisting in the proper coaptation
of the heart valve leaflets, either against one another or
independently against another surface. Assisting this coaptation
may be accomplished by directly geometrically altering the shape of
the dysfunctional mitral valve annulus, by repositioning one or
both of the papillary muscles to a more normal state, and/or by
otherwise facilitating annular contraction during systole. In
addition, these devices may be placed in conjunction with other
devices that, or may themselves function to, alter the shape or
geometry of one or more heart ventricles, locally and/or globally,
and thereby further increase the heart's efficiency. That is, the
heart may experience an increased pumping efficiency and
concomitant reduction in stress on the heart walls through an
alteration in the shape or geometry of one or more of the
ventricles and through an improvement in valve function.
[0106] The inventive devices and related methods may offer numerous
advantages over the existing treatments for various valve
insufficiencies. The devices are relatively easy to manufacture and
use, and the surgical techniques and tools for implanting the
devices of the present invention do not require the invasive
procedures of current surgical techniques. For instance, the
surgical techniques do not require removing portions of the heart
tissue, nor do they necessarily require opening the heart chamber
or stopping the heart during operation. All of the techniques
described may be performed without placing the patient on
cardiopulmonary bypass, which, as discussed above, is routinely
required for conventional procedures to repair and/or replace the
mitral valve. Avoiding placing the patient on cardiopulmonary
bypass may permit the inventive devices and related methods to be
adjusted "real time" so as to optimize the performance of the
valve. Furthermore, the inventive devices and related methods may
avoid the need to place the patient on long-term anticoagulation,
which currently is required for many current valve repair
techniques. For these reasons, the surgical techniques for
implanting the devices of the present invention also are less risky
to the patient than other techniques. The less invasive nature of
the surgical techniques and tools of the present invention may also
allow for earlier intervention in patients with heart failure
and/or valve incompetencies.
[0107] Although many of the methods and devices are discussed below
in connection with their use in the left ventricle and for the
mitral valve of the heart, these methods and devices may be used in
other chambers and for other valves of the heart for similar
purposes. The left ventricle and the mitral valve have been
selected for illustrative purposes because a large number of the
disorders that the present invention treats occur in connection
with the mitral valve. Furthermore, as will be shown, certain
devices disclosed herein for improving valve function can be used
either as stand-alone devices (i.e., solely for treatment of valve
insufficiency) or in conjunction with other devices for changing
the shape of a heart chamber or otherwise reducing heart wall
stress.
[0108] Reference will now be made in detail to some optional
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
numbers will be used throughout the drawings to refer to the same
or like parts.
[0109] FIG. 1a is a short-axis cross-sectional view of the heart
illustrating the mitral valve MV in relation to the other valves of
the heart, namely, the aortic valve AO, the tricuspid valve TV, and
the pulmonary valve PV. The mitral valve has two leaflets, an
anterior leaflet A and a posterior leaflet P. The anterior leaflet
A is adjacent the aorta, AO, and the posterior leaflet P is
opposite the aorta AO. An annulus AN surrounds the mitral valve
leaflets. FIG. 1b is a partial short-axis cross-sectional view
showing the mitral valve MV in relation to the coronary sinus CS.
The coronary sinus CS wraps around a significant portion of the
posterior aspect of the mitral valve annulus AN. The ostium OS of
the coronary sinus CS drains into the right atrium RA.
[0110] In FIGS. 2a and 2b, a top view of a properly functioning
mitral valve MV is shown. FIG. 2a shows the valve MV in its open
position during diastole in which the posterior leaflet P is
separated from the anterior leaflet A. Portions of the chordae C
also can be seen in FIG. 2a. FIG. 2b shows the properly functioning
mitral valve MV in the closed position during systole. In this
figure, the anterior leaflet A and the posterior leaflet P contact
one another along a line of coaptation to close the mitral valve MV
and prevent blood from flowing through the valve MV from the left
atrium to the left ventricle.
[0111] FIG. 2c shows a top view of an improperly functioning mitral
valve MV in the "closed" position (i.e., during systole). In FIG.
2c, the anterior leaflet A and the posterior leaflet P do not
properly co-apt when the valve MV is in the closed position. This
may be caused by, for example, a dilatation of the annulus AN
caused by an enlargement of the left ventricle, or other similar
mechanisms discussed above. As shown in FIG. 2c, this improper
coaptation prevents the complete closure of the orifice O between
the valve leaflets, thereby permitting blood to leak through the
valve from the left ventricle to the left atrium during systole. In
other words, although the mitral valve is in a contracted state, it
is not actually closed so as to prevent blood flow therethrough
since the leaflets are prevented from completely coming
together.
[0112] FIG. 3a shows a side view of a properly functioning mitral
valve in the closed position with the valve leaflets L properly
coapted so as to prevent blood flow through the valve. FIG. 3b
shows a side view of an improperly functioning mitral valve in
which the valve leaflets L are not properly coapted due to, for
example, dislocation of the papillary muscles PM. Such dislocation
of the papillary muscles also may be caused by enlargement of the
left ventricle, for example. The arrows in FIG. 3a show the
movement of the papillary muscles PM down and to the right
resulting from such ventricle dilatation.
[0113] Such dysfunctioning valves, as shown in FIGS. 2c and 3b, may
cause a reduction in forward stroke volume from the left ventricle.
Also, a blood flow reversal into the pulmonary veins may occur.
Mitral valve regurgitation may also arise from a combination of
valve annulus dilation and papillary muscle dislocation.
[0114] It should be noted that dilatation of the left ventricle
represents an example of a condition that can lead to improper
valve function. Other conditions, discussed above, also may cause
such valve dysfunction, and the devices and techniques discussed
herein can be used to treat valve insufficiencies caused by these
conditions.
[0115] Exemplary embodiments of a device for treating the mitral
valve via a change in shape of the valve annulus, which may include
a reduction in the effective circumference of the valve annulus,
are shown in FIGS. 4a-4i. The devices of FIGS. 4a-4i may be
implanted on a beating heart, without the need for cardiopulmonary
bypass. The devices of FIGS. 4a-4i comprise curved frame members
configured to be inserted into the coronary sinus to effect a shape
change of the posterior aspect of the mitral valve annulus. In
certain embodiments, as will be discussed, the frame members
include mechanisms that allow for creating a focused shape change
at selected locations along a portion of the mitral valve annulus
adjacent the frame members. That is, the frame members may allow
for differing shape change effects along the length of the frame
member. The ability to selectively alter the shape in one region of
the annulus differently than another region may be particularly
advantageous when treating patients whose mitral valve
insufficiency has arisen from local myocardial ischemia or
infarction, since such patients may experience relatively localized
geometrical alterations of the mitral valve annulus, as opposed to
an overall radial increase of the annulus.
[0116] As shown in FIG. 4a, a curved frame member 110a is
configured to be delivered endovascularly to and implanted in the
coronary sinus CS. The origin of the coronary sinus CS is located
in the wall of the right atrium (not shown), and may be accessed
by, for example, catheterization of the femoral, jugular, or
subclavian veins, so as to endovascularly implant the frame member
110a. Alternatively, the frame member 110a could be implanted via a
surgical approach. In any case, the frame member 110a may be
positioned in the coronary sinus CS proximate the posterior aspect
of the mitral valve annulus, as shown in FIG. 4a. In this position,
the frame 110a may be used to alter the shape of the posterior
aspect of the valve annulus, creating a configuration that
effectively reduces the annular circumference and/or creates a
greater degree of coaptation between the anterior and posterior
leaflets A, P. Alternatively, the frame member 110a may be used to
stabilize the shape of the posterior aspect of the valve annulus,
thereby substantially preventing continued dilation or deformation
of the valve annulus.
[0117] The frame member 110a may be made of a substantially rigid
material such that the frame member 110a can be bent or otherwise
formed into the desired shape and placed within the coronary sinus
CS, causing the annulus of the mitral valve MV, or portions
thereof, to change shape. The frame member 110a may engage within
the coronary sinus CS via a friction fit to maintain its position
within the coronary sinus CS. A further alternative is to fabricate
the frame member 110a of a shape memory material, such as
nickel-titanium alloy, for example. In this manner, the frame
member 110a may be chilled prior to implantation such that it has
some flexibility. This may permit the frame member 110a to be
introduced into the coronary sinus CS in a relatively atraumatic
manner. Once in place, the blood may warm the frame member 110a,
causing a shape change to a preformed initial shape. This shape
change of the frame member 110a may in turn alter the shape of the
coronary sinus CS and thus the valve annulus.
[0118] As shown in FIG. 4b, one or both ends of the frame member
110a may exit the coronary sinus CS and anchor assemblies 105 may
be provided on the ends of the frame member 110a. This may allow
the frame member 110a to impart a shape change to the valve annulus
beyond the somewhat limited extent of the coronary sinus CS around
the posterior aspect of the valve. The frame member 110a may be
anchored to an exterior surface of the heart wall via the anchor
assemblies 105. The ends of the frame member 110a may puncture
through the coronary sinus CS to pass externally and allow
connection of the anchor assemblies 105 to the exterior surface of
the heart. The anchor assemblies 105 may be in the form of anchor
pads. Some examples of such anchor pads are described in U.S.
application Ser. No. 09/680,435, incorporated above. The anchor
assemblies 105 may be sutured, or secured by other similar
attachment mechanisms, such as by providing a surface of the anchor
assemblies 105 with a tissue ingrowth promoting material, to an
exterior surface of the heart wall to hold the frame 110a in place
with respect thereto. To further facilitate obtaining the desired
shape change of the mitral valve annulus, the anchor assemblies 105
may be positionable along the length of the frame member 110 prior
to fixation of the frame member 110 with respect to the heart or
the frame member 110 may have a variable length. For example, the
frame member 110a may be provided with a telescoping mechanism or
the like.
[0119] In yet another exemplary embodiment, as shown in FIG. 4c,
the frame member 110c may be configured to anchor itself into the
vessel wall in order to maintain its position. For example, in the
optional configuration shown in FIG. 4c, the frame member 110c is
provided with barbs 111 along its length. The frame member 110c may
be delivered endovascularly such that the barbs 111 do not engage
the wall of the coronary sinus CS. Once the frame member 110c is
placed within the coronary sinus CS in the desired position, it may
be manipulated, for example, by rotation or by moving the frame
member 11c in a direction opposite to the direction of advancement
through the coronary sinus CS, so as to engage the barbs 111 with
the coronary sinus wall. This engagement helps to maintain the
position of the frame member 110c.
[0120] FIG. 4d shows another embodiment of a curved frame member
10d configured to be implanted in the coronary sinus CS for
treating the mitral valve. In this embodiment, the frame member
110d may support a shape change element 106 configured to move
along a length of the frame member 110d. The shape change element
106 may be configured to protrude radially with respect to the
frame 110d, thereby providing a more localized shape change in an
area along the posterior aspect of the mitral valve. A desired
location for the shape change may be determined by moving the shape
change element 106 along the length of the frame member 110d to a
particular position and viewing the effects on mitral valve
function through real-time imaging techniques. The shape change
element 106 also may be detachable from the frame member 110d for
easy removal from the frame member 110d if the localized shape
change is no longer desired. The shape change element 101 may be
mechanically detachable or it may be detached electrolytically in a
manner similar to the detachment mechanism of the Guglielmi
detachable coil. A delivery tool, which may be in the form of a
delivery wire 106', may be used to deliver the shape change element
101 over the frame member
[0121] FIG. 4e shows another exemplary embodiment of a curved frame
for insertion into the coronary sinus proximate the posterior
aspect of the mitral valve. In this embodiment, the frame member
110e serves as a support for an adjustable shape change member 107.
As an example, the curved frame 110e may define at least one slot
108 extending along at least part of the length of the frame 110e.
A moveable pin 109 may engage with the slot 108 so as to slide
along the length of the slot 108. A wire 112 may extend along the
portion of the curved frame 110e that lies adjacent the posterior
aspect of the mitral valve annulus. The wire 112 may have one end
attached to the pin 109 and an opposite end attached at an end of
the frame 110e substantially opposite to the moveable pin 109. For
example, as shown in FIG. 4e, the wire 112 may be attached to a
fixed pin 109'. Alternatively, the wire may attach directly to the
frame member 110e. Upon movement of the pin 109 toward a center of
the frame member 110e, the wire 112 curves, forming a bulge that
causes the mitral valve annulus to change shape.
[0122] The frame member 110e optionally may have two pins disposed
at opposite ends of the frame in either a single slot running
substantially the entire length of the frame 110e or two different
slots disposed at substantially opposite ends of the frame 110e. In
an exemplary embodiment, both of the pins 109, 109' shown in FIG.
4e, may be moveable. In either case, the movement of one pin or
both pins may cause the wire 112 to bulge outward, thereby
imparting a variable degree of shape change to the mitral valve
annulus. Preferably, the wire 112 is sufficiently flexible so as to
permit bending of the wire due to the movement of the pin 109
within the slot 108. However, the wire 112 also should be
sufficiently rigid so as to maintain its bulged configuration and
cause the desired shape change and/or repositioning of the valve
annulus and/or papillary muscles.
[0123] FIGS. 4f and 4g illustrate yet another exemplary embodiment
of a curved frame member 110f for implanting in the coronary sinus
to alter the shape of the mitral valve annulus. FIG. 4f is a
perspective view of the frame member 110f, which is formed from
segments 113 configured to rotate relative to each other. Rotating
the segments 113 about their respective longitudinal axes and
relative to each other may alter the curvature of the frame 110f
along its length so as to produce various degrees of curvature in
particular locations as desired. Such curvature of the frame member
110f is illustrated in FIG. 4g. As a direct surgical implant, the
curved frame member 110f can have its segments 113 individually
manipulated via direct rotation to achieve a desired final shape
prior to insertion into the coronary sinus CS. A wire (not shown)
extending down the center of the segments 113 may hold the segments
113 in their final desired configuration, for example, due to
frictional engagement.
[0124] In another contemplated embodiment, shown in FIGS. 4h and
4i, a curved frame member 110h may comprise an actuation mechanism
90 attached to a portion of the frame member 110h. For example, the
actuation mechanism 90 may be attached to a distal end of the frame
member 110h. The frame member 110h may be formed of a plurality of
substantially wedge-shaped segments 95. Actuating the actuation
mechanism 90, by, for example, pulling mechanism 90 proximally,
causes the distal end to retract so as to change the shape of the
frame member 110h, as shown in FIG. 4i. This in turn may alter the
shape of the mitral valve annulus when the frame member 110h is
implanted in the coronary sinus CS. The actuation mechanism 90 may
comprise a pull-actuated wire attached to a distal end of the frame
member, as shown in FIGS. 4h and 4i, or alternatively to an anchor
assembly provided on the distal end of the frame member. The
desired final shape of the frame member 110h may reduce or enlarge
a radius of curvature of the valve annulus, or a combination of
both, i.e., increasing the curvature in some regions and decreasing
the curvature in other regions.
[0125] The various curved frame devices of FIGS. 4a-4i may be
configured to be implanted on a beating heart. Optionally, the
frame devices may be implanted during an open chest or minimally
invasive thoracic surgical procedure. For example, the frame member
may be directly inserted into the coronary sinus through an
incision in either the right atrium or the coronary sinus. In an
alternative exemplary embodiment, the frame devices could be
implanted endovascularly into the coronary sinus using
catheter-based delivery techniques. For example, a catheter may be
inserted into either the jugular vein or the vena cava and into the
right atrium and then the coronary sinus.
[0126] FIGS. 5a-5e show an exemplary embodiment of a floating ring
device for treating mitral valve dysfunction by altering the shape
of the mitral valve annulus. The floating ring device according to
the invention may be implanted into the region of the mitral valve
annulus itself (either above, at, or below the annulus) in order to
effect the desired shape change of the mitral valve annulus.
[0127] A short axis cross-sectional view of the heart implanted
with an exemplary embodiment of a floating ring device 115 is shown
in FIG. 5d. The device comprises a semi-flexible ring 116
configured to be placed in the left atrium LA, proximate the mitral
valve annulus. A plurality of tightening members 117, which may
have the form of tension members, are secured to the ring 116. An
anchor mechanism, for example in the form of a pad 118, attaches to
the free end of each tightening member 117 opposite to the ring
116. The anchor pads 118 are adapted to be secured to the
tightening members 117 and placed externally of the heart wall, for
example on the posterior wall of the left atrium LA, to secure the
floating ring device 115 in place with respect to the heart. Prior
to securing the anchor pads 118 to the tightening members 117, the
tightening members 117 may be tightened (i.e., their lengths
between the valve annulus and heart wall altered) until the desired
annular shape of the mitral valve is obtained. The tightening
members 117 may be individually tightened to produce differing
effects on the shape of the mitral valve annulus depending on the
position around the annulus. The flexibility of the ring 116 also
may assist in producing a varying effect on the mitral valve
annulus geometry. It is contemplated that sutures or other
attachment mechanisms may be employed instead of the anchor pads
118 to secure the tightening members 117 to the heart wall once the
desired tensioning of the tightening members 117 has been
achieved.
[0128] Referring to FIGS. 5a-5d, an exemplary delivery technique
for implanting a floating ring device will be described. The
technique described preferably is performed on a beating heart. As
shown in FIG. 5a, a snare 119 is first delivered through a
relatively small incision in the wall of the appendage of the left
atrium LA. As an example, the incision may be made at a location
superior to the mitral valve MV. A trocar (not shown) also may
assist in the delivery of the snare 119 through the incision. The
snare 119 comprises a loop portion 119a at a distal end of the
device and a handling portion 119b extending from the loop portion
119a. The handling portion 119b forms a proximal end of the snare
119. The handling portion 119b may extend out of the left atrium
upon deployment of the snare 119 within the heart. According to an
alternative aspect, the snare 119 may be delivered through the
venous system to the right atrium (not shown) and then into the
left atrium LA via the atrial septum. In either case, once the
snare 119 is delivered into the left atrium LA, the loop portion
119a may be positioned with its perimeter resting on substantially
the outermost edges of the mitral valve annulus AN.
[0129] After appropriately positioning the snare 119 with respect
to the mitral valve annulus AN, a plurality of tightening members
117, which may have a substantially filament-like structure, may be
inserted from external the heart, through the wall of the left
atrium LA, and into the left atrial chamber. For example, as shown
in FIG. 5b, a hollow, needle-like delivery tool 300 may be used to
insert the tightening members 117 through the heart wall by
inserting the delivery tool 300 carrying the tightening members 117
through the heart wall and ejecting the members 117 out of the
delivery tool 300.
[0130] As shown in FIG. 5b, the tightening members 117 may be
positioned along the posterior aspect of the mitral valve MV
approximately at the level of the mitral valve annulus AN. As the
tightening members 117 are inserted into the atrial chamber, they
may be carried through the snare loop 119a via the blood flowing
from the left atrium LA through the mitral valve MV and to the left
ventricle LV. To facilitate delivery of the tightening members 117,
especially with regard to their insertion through the heart wall,
the tightening members 117 optionally may be attached to needles
which penetrate the heart wall first. In this case, the bloodflow
would carry the needles with the tightening members 117 attached
from the left atrium LA and through the snare loop portion
119a.
[0131] Once the tightening members 117 have been drawn through the
snare loop portion 119a, the snare 119 may then be retracted and
the tightening members 117 captured within the loop portion 119a.
By pulling proximally on the handling member 119b, the snare 119
with the captured tightening members 117 may be retrieved from the
left atrium LA. As shown in FIG. 5c, the free ends of the
tightening members 117 may be pulled out of the left atrium
appendage through the incision previously made to insert the snare
device 119. The snare device 119 may be removed from the tightening
members 117 once they are pulled out of the left atrium LA.
[0132] The free ends of the tightening members 117 may then be
secured to the flexible ring 116, for example, by tying the ends to
the ring. The flexible ring 116 may then be reinserted into the
left atrium LA by pulling on the tightening members 117 at their
respective insertion points in the left atrial wall. Thus, the
flexible ring 116 may be inserted through the same delivery path
that was used to insert the snare 119.
[0133] The flexible ring 116 preferably has enough flexibility so
as to permit insertion of the ring 116 into a trocar and/or an
incision made in the left atrial appendage and through the left
atrium LA. Furthermore, the ring 116 and the tightening members 117
preferably are covered with a hemocompatible material, such as
expanded PTFE, for example. This covering may facilitate the
endothelialization of any portion of the ring 116 and tightening
members 117 residing in the blood flow path near the mitral
valve.
[0134] After tightening each tightening member 117 to a desired
amount, a securing mechanism, such as the anchor pads 118 shown in
FIG. 5d, may secure the tightening members 117 externally to the
heart wall. Depending on the position and number of tightening
members 117, and the relative degree of tightening of each, various
annular geometries of the mitral valve may be obtained.
Echocardiographic visualization may be employed to assist in
adjusting the floating ring device. For example, the device can be
selectively tightened in various locations and/or to various
degrees until minimal or no mitral valve regurgitation is observed
using the echocardiographic visualization.
[0135] A further exemplary embodiment of a floating ring device is
illustrated in FIG. 5e. In this embodiment, the anterior-most pairs
of tightening members 117e are relatively rigid. A single elongate
anchor pad 118e connects to the ends of each of the pairs of
tightening members 117e. In this manner, the position of the ring
116 over the central portion of the mitral valve may be maintained,
even as the posterior-oriented tightening members 117e are
tightened.
[0136] Yet another optional embodiment of a device for treating the
mitral valve is illustrated in FIGS. 6a-6d. The device shown in
these figures is referred to herein as an "annular noose," so-named
due to its noose-like configuration. The annular noose 120 is
formed from a flexible rope-like member 121. The member 121 may be
made of a braided polyester, or other similar material, that allows
the member 121 to flex without forming kinks and/or permanent
bends. The rope-like member 121 is shaped into a loop portion 122
that is placed around the exterior of the left atrium (not shown),
as close as possible to the atrioventricular groove (not shown),
and in substantially the same plane as the mitral valve annulus AN.
It may be necessary for the portion between the anterior leaflet
and the aorta to be passed through the tissue of the left atrium.
An adjusting mechanism manipulable from external the heart, such as
a cinch ring 125, for example, may be used to adjust the size of
the loop portion 122 and secure the free ends 123a, 123b of the
member 121 that extend from the loop portion 122. After the loop
portion 122 has been properly positioned with respect to the mitral
valve annulus AN, the cinch ring 125 may be tightened, thereby
permitting a reduction in the circumference of the mitral valve
annulus AN.
[0137] FIGS. 6b and 6c show various elements that may be used in
conjunction with the annular noose 120 of FIG. 6a so as to provide
a more focused geometrical shape change in selected regions of the
mitral valve. For example, as shown in both FIGS. 6b and 6c, a
relatively rigid member 126 may be placed over the flexible member
121. In the optional embodiment shown in FIGS. 6b and 6c, the
relatively rigid member 126 has a tubular configuration that may be
advanced over either of the free ends of the flexible member 121
and positioned as desired along the loop portion 122.
Alternatively, the relatively rigid member 126 may be permanently
secured to the loop portion 122 of the flexible member 121. In the
embodiment of FIG. 6b, the annular noose 120, with the relatively
rigid member 126 disposed thereon, is positioned with respect to
the mitral valve MV such that the relatively rigid member 126 rests
by the anterior leaflet side of the mitral valve MV. This placement
may permit a more focused circumferential reduction to take place
at a location proximate the posterior leaflet, since this portion
is more flexible and will tend to draw the noose down as it is
tightened.
[0138] FIG. 6c shows another embodiment of an element for use in
conjunction with the annular noose 120. A shape change securing pad
127 may be used for adjusting the size of the loop portion 122 and
for securing the free ends 123a, 123b. As shown in FIG. 6c, the
shape change pad 127 may have a substantially disk-like
configuration with a central, substantially longitudinal passage
through which the ends 123a, 123b of the flexible member 121
extend. A securing pin 128 may operate to move toward and away from
the center of the pad to pass through the flexible members ends
123a, 123b and secure the annular noose 120 into position. A
surface 129 of the pad 127 that faces the mitral valve annulus may
have a substantially non-concave profile, for example the surface
129 may be either convex or flat. When the pad 127 is moved so as
to tighten the annular noose 120, the pad 127 may press against the
mitral valve annulus and thereby cause a relatively focused shape
change in the region of the pad 127.
[0139] As shown in FIG. 6d, a plurality of pads 127 may be used to
change the shape of the mitral valve in the regions of the mitral
valve proximate the pads. Such a focused change may permit
increased co-aptation of the valve leaflets in the various regions
of the focused shape change. The shape change pad 127 and the
relatively rigid member 126 may be used either in combination, as
shown in FIG. 6c, or individually to create a focused shape change
of the mitral valve. Such a focused shape change is in addition to
the overall circumferential reduction achieved by the annular noose
120 alone.
[0140] FIG. 6e illustrates an alternative exemplary embodiment of a
noose device. The noose device in FIG. 6e comprises a relatively
rigid member 126e, similar to the relatively rigid member 126 of
FIG. 6b. The member 126e is positioned on the posterior side of the
mitral valve MV. Preferably, the rigid member 126e, which is placed
on the loop portion 122, may be formed by bending or the like to a
desired shape so as to impart a desired shape change to the
posterior annulus. The rigid member 126e can be of any desired
shape, and may include one or more local regions of
indentations.
[0141] Another aspect of the present invention includes an internal
strut device that operates to treat mitral valve dysfunction by
causing a shape change to the mitral valve annulus while
maintaining or restoring the normal distance between the trigones
of the valve. The device also may move the posterior leaflet face
closer to the anterior leaflet face. Combined, these movements tend
to increase the coaptation area of the mitral valve leaflets and
improve mitral valve function. An exemplary embodiment of an
internal strut device is shown in FIGS. 7a and 7b.
[0142] The embodiment of the internal strut device shown in FIGS.
7a and 7b generally comprises a relatively rigid elongate member
130 positioned so as to extend substantially along the line of
leaflet coaptation of the mitral valve. The relatively rigid
elongate member 130 may be positioned in close proximity to the
valve annulus AN, either slightly above or slightly below the
annulus AN, so as to appropriately affect the valve leaflets and
move them into a desired position. A second elongate member 136 may
be provided so as to extend substantially perpendicular to the
relatively rigid elongate member 130 and to the line of leaflet
coaptation. The relatively rigid elongate member 130 may be fixed
to the outer walls of the left atrium or the left ventricle,
depending on the positioning of the member 130 with respect to the
mitral valve MV. Sutures, anchor pads, or other similar mechanisms
may secure the member 130 with respect to the leaf. FIGS. 7a and 7b
illustrate the use of anchor pads 132 for securing the relatively
rigid, elongate member 130.
[0143] Providing a relatively rigid elongate member 130 may
substantially prevent the member from bending or buckling, which
may in turn help to maintain the desired trigonal distance. The
member 130 may be a rigid bar made from biocompatible metals, such
as nitinol, titanium, chrome-alloys, MP-35N, and other similar
metals, or from biocompatible polymers, such as PEEK, acetyl, or
other similar materials. Optionally, the bar may be an extendable,
telescoping bar (not shown). This may permit the length of the bar
to be adjusted as necessary to optimize the trigonal distance.
[0144] The second elongate member 136 may optionally be in the form
of a snare having a loop portion 136a that is secured around the
relatively rigid member 130. The snare may be tightened as desired
and the free end 136b may be secured via an anchor pad 134 placed
adjacent an exterior surface of the heart wall. Once secured, the
snare essentially forms a tension member anchored at one end to the
relatively rigid member 130 and at the opposite end to the heart
wall. Together, the relatively rigid member 130 and the second
elongate member 136 impart a shape change to the mitral valve
annulus, while maintaining the distance between the valve trigones
T. Alternatively, the distance between the valve trigones also may
be altered to achieve a more normal distance between them if
necessary.
[0145] An exemplary embodiment for the delivery and implantation of
the internal strut device of FIGS. 7a and 7b will now be explained.
An introducer 138, such as a trocar or other suitable introducer
mechanism, may be inserted through the heart wall proximate the
level of the mitral valve annulus AN. As shown in FIG. 7a, the
introducer 138 may be inserted in a substantially perpendicular
direction relative to the line of coaptation of the mitral valve
leaflets. Once the introducer is inserted, the second elongate
member 136, in the form of a snare in FIGS. 7a and 7b, may be
inserted through the introducer 138 and positioned with the loop
portion 136a substantially in the middle of the mitral valve
annulus AN. The relatively rigid elongate member 130 may then be
inserted through the left atrial wall (not shown) at approximately
the same annular level as the snare 136. However, the member 130 is
advanced in a direction along the line of coaptation of the mitral
valve leaflets and substantially perpendicular to the snare 136.
The member 130 may be passed through the loop portion 136a of the
snare 136 and through the wall surrounding the left atrium located
substantially opposite to the wall through which the member 130 was
inserted. Once extended transverse the left atrium LA, securing
mechanisms, such as anchor pads 132, for example, may fix the
member 130 with respect to the heart. Prior to securing the member
130, its length between the chamber walls may be adjusted, as
described above, in order to alter the distance between the valve
trigones as desired.
[0146] Once the relatively rigid elongate member 130 is secured
into position, the snare loop portion 136a may be tightened around
it and the snare 136 secured on the external surface of the atrial
wall by a securing mechanism, such as anchor pad 134 as shown in
FIG. 7b. Thus, the snare 136 also may induce a shape change to the
mitral valve annulus AN, as shown by the indented region of the
mitral valve annulus in FIG. 7b. Both the relatively rigid elongate
member 130 and the snare 136 may have their lengths adjusted as
necessary to provide the overall desired shape change of the mitral
valve annulus. The snare 136 may optionally be secured using a
securing mechanism that extends from the annular level of the left
atrium LA down the epicardial surface to a region proximate the
left ventricle LV. This would allow the strut device to change the
shape of the mitral valve both at a level of the valve annulus and
at a subvalvular level.
[0147] In an alternate embodiment (not shown), the relatively rigid
bar may be replaced by a splint assembly similar to the splint
assemblies disclosed in U.S. application Ser. No. 09/680,435,
incorporated by reference herein. Such a splint assembly would be
relatively flexible and capable of adjusting in length by adjusting
the position of the anchor members with respect to the tension
member of the splint assembly. The splint assembly may extend along
the line of coaptation of the valve leaflets. In this case, the
length of the tension member between the heart walls may be
adjusted in order to maintain or achieve a more desirable trigonal
distance.
[0148] Yet another exemplary embodiment for treating a heart valve
includes an intrawall splint comprising an elongate member
configured to be implanted within the heart wall so as to extend
around a portion of the chamber. The elongate member may optionally
be either wire-like, similar to the braided tension members used
with the splint assemblies of U.S. application Ser. No. 09/680,435,
incorporated by reference herein, or tubular. Because the device of
this optional embodiment is implanted within and exterior to the
heart wall, there is substantially no blood contact with the
device, reducing the risk of thrombus formation.
[0149] An example of an intrawall splint 140 according to an
exemplary embodiment of the invention is shown in FIG. 8. The
intrawall splint 140 comprises an elongate member 141 that may be
implanted within the lateral myocardial wall of the heart,
optionally near the atrio-ventricular groove, in an area
substantially coinciding with or slightly offset from the annular
edge of the posterior leaflet. In the embodiment shown in FIG. 8,
the elongate member 141 is secured to the heart using anchor
assemblies 148, which may have configurations similar to those
discussed with reference to FIGS. 4b, 5d, 7a, and 7b, for example.
The anchor assemblies 148 attach to the end portions of the
elongate member 141 at an exterior surface of the heart wall. The
anchor assemblies 148 may move along the length of the elongate
member 141 to adjust the degree of compression on the heart wall.
By appropriately positioning the anchor assemblies 148 on the
elongate member 141, the arc length of the mitral valve annulus
along the posterior side of the valve may be reduced. This may
increase the coaptation area between the valve leaflets and
decrease the annular cross-section. Once a suitable degree of shape
change of the valve annulus occurs, which may be determined by
observing the mitral valve regurgitation through the use of
echocardiagraphic or other similar visualization techniques, the
anchor assemblies 148 may be fixed to the elongate member 141 to
hold the elongate member 141 in place with respect to the heart.
The elongate member 141 and the anchor assemblies 148 shown in FIG.
8 may be implanted in a manner similar to the implantation
techniques for the splint assemblies of U.S. application Ser. No.
09/680,435, incorporated by reference herein.
[0150] The elongate member 141 may be made of bio-inert,
bio-stable, and/or bio-resorbable materials. In each of these
cases, the implantation of the elongate member 141 within the heart
wall may provoke a healing response by the heart wall. This healing
response may elicit a chronic process that results in the shrinkage
of the tissue in a direction along the axis of the elongate member.
In another exemplary configuration, the elongate member 141 may be
configured so as to deliver heat to the heart wall during delivery.
Such heat also may initiate a healing response in the heart wall
tissue, resulting in tissue shrinkage along the elongate member.
For example, the member 141 may be made of a conductive metal and
be heated, such as by temporarily exposing it to an electrical
current, preferably in the RF range. In an exemplary embodiment,
the RF range will be chosen so as to minimize electrical
interference with the heart's conduction system.
[0151] Another exemplary embodiment of the invention includes an
external plication device that may be positioned on an exterior
surface of the heart wall near the posterior mitral valve annulus
in substantially the same plane as the annulus. As with other
devices discussed herein, such an external plication device may be
placed so as to reduce the valve annulus cross-section and increase
the valve leaflet coaptation area. FIG. 9 shows an example of an
external plication device 150 according to an aspect of the
invention. The external plication device 150 comprises a curved rod
151 anchored on an exterior surface of the heart wall by a series
of sutures 152. A series of tissue anchors may be used instead of
sutures. The rod 151 may be shortened, for example, by telescoping,
to a fixed length to provide a reduction of the lateral heart wall
and/or posterior annular space. Alternatively, the external
plication device may be implanted so as to reposition the papillary
muscles, such as by reducing the intrapapillary distance, for
example.
[0152] The rod 151 may be either relatively rigid or relatively
flexible. A relatively flexible rod 151 may take the form of a
tension member, such as the tension members used with the splint
assemblies of U.S. application Ser. No. 09/680,435, incorporated by
reference herein. A relatively rigid rod may be preferable to
provide a local shape change, while a relatively flexible rod may
be preferable for changing the arc length of at least a portion of
the valve annulus. The external plication device may be made of
biocompatible materials. Alternatively, the external plication
device may be made of bioresorbable materials that provoke a
chronic healing response of the heart wall tissue. This healing
response may result in a scarring, causing the tissue to shrink in
a particular direction, thereby reducing the posterior annular arc
length.
[0153] As with the intrawall splint device of FIG. 8, the external
plication device is implanted so as to substantially avoid blood
contact within the heart chamber, which reduces the risk of
thrombus formation.
[0154] The devices of FIGS. 8 and 9 are shown in position on the
lateral wall of the heart proximate the posterior aspect of the
mitral valve annulus. It is contemplated, however, that these
devices may be implanted in other positions with respect to the
heart while still helping to reduce mitral valve regurgitation or
to treat other heart valves altogether.
[0155] Yet another aspect of the invention includes the use of
so-called "plug" devices, for treating incompetent heart valves.
These plug devices are intended assist in closing the mitral valve
to prevent regurgitation by increasing the coaptation area of the
mitral valve leaflets and/or decreasing the coaptation depth of the
mitral valve leaflets. This generally may be accomplished by
placing a plug device in the "hole" between the valve leaflets
(i.e., the valve orifice), thereby providing a surface against
which the valve leaflets may abut (i.e, coapt), in order to close
the mitral valve during systole. The plug devices described herein
assist in closing the mitral valve substantially without altering
the shape of the valve annulus and/or repositioning the papillary
muscles. To further understand how the plug devices according to
optional aspects of the invention operate to improve mitral valve
function, reference is made to the various optional embodiments of
the device shown in FIGS. 10b-11m(ii).
[0156] FIG. 10a illustrates a schematic side view of the leaflets L
of a dysfunctional mitral valve during systole. As seen in this
figure, the leaflets L do not coapt so as to close the mitral valve
orifice. Therefore, regurgitant flow will occur through the valve
during systole. FIG. 10b illustrates the valve of FIG. 10a during
systole with an exemplary embodiment of a plug member 160 of the
present invention implanted in the valve leaflet coaptation space.
As can be seen, the presence of the plug member 160 will block the
regurgitant flow through the valve during systole as the leaflets L
abut against the outer surface of the plug member 160. In other
words, the plug member 160 "plugs" the valve orifice during systole
to hinder or prevent blood from leaking through the valve.
[0157] In the exemplary embodiments of FIGS. 11a-11f, a plug member
is suspended in the coaptation space substantially in the area
where regurgitant blood flow occurs. The suspended plug member may
have a variety of shapes depending on factors such as the mitral
valve geometry, the alignment of the valve leaflets, and the size
and shape of the regurgitant opening during systole. For example,
the suspended plug member may have a spherical configuration (160a
in FIG. 11a), an ellipsoidal configuration (160b in FIG. 11b), a
disk-shaped configuration (160c in FIG. 11c), a wing-like
configuration (160d in FIG. 11d), or a sheet-like configuration
(160e in FIG. 11e, 160f in FIG. 11f). FIGS. 11a-11e show
schematically a partial cross-sectional view of the mitral valve
with the various plug members disposed between the valve leaflets L
and within the valve orifice.
[0158] In FIGS. 11a-11d, the valve is shown in an open position,
with a space between the valve leaflets L and the outer surface of
the plug member 160a-160d to allow blood flow therethrough. During
closure of the valve, the leaflets L abut against the outer surface
of the plug member 160a-160d, thereby preventing regurgitation
through the valve orifice, which may otherwise occur if the
leaflets are unable to properly coapt against one another. FIG. 11e
shows schematically a partial cross-sectional view of a mitral
valve during systole with a plug member 160e disposed between the
valve leaflets L. The presence of the plug member 160e permits the
valve to close during systole as a result of the valve leaflets L
coapting against the surface of the plug member 160e. This
coaptation will substantially prevent regurgitant blood flow from
occurring during systole.
[0159] A suspended member 160d having a wing-like configuration, as
shown in FIG. 11d, may provide an advantageous surface for the
valve leaflets L to close against due to its tapered configuration.
The tapered configuration substantially mutually corresponds to the
profile of the valve leaflets surfaces themselves. Such a tapered
and mutually corresponding shape may help to reduce thrombus
formation at the blood-surface contact points with the suspended
member 160d. Moreover, this shape may reduce insult to the valve
leaflets L as they close against the surface of the suspended
member 160d.
[0160] A suspended member 160e having a substantially sheet-like
configuration may be particularly suitable for use as a plug device
in patients having misaligned leaflets. In this case, as shown in
FIG. 11e, the ends of the valve leaflets L tend to reach the
centerline of the valve as they come together during systole.
However, the leaflets L are arranged such that the ends of the
leaflets L are in different transverse planes upon closing of the
valve, therefore hindering proper coaptation and valve closure. The
substantially planar plug member 160e in FIG. 11e may be suspended
substantially along the centerline of the valve, providing the
misaligned valve ends with a surface to abut against. Due to its
substantially planar configuration, the plug member 160e may
minimize the cross-sectional area of the blood flow path that is
blocked by the device, while also providing the desired closure of
the valve. In an alternative embodiment, shown in FIG. 11f, the
sheet-like plug 160f may be constructed of two layers sealed along
their perimeters. This embodiment therefore may form an inflatable
structure. Such an inflatable plug member may permit the
cross-section of the member to be selected and varied according to
the size of the "hole" between the improperly coapting valve
leaflets.
[0161] As shown in the FIGS. 11a-11f, the plug members 160 operate
to reduce mitral valve regurgitation and improve valve function by
providing a surface against which the mitral valve leaflets may
coapt during systole, thereby closing the valve to blood flow
therethrough. Thus, these plug members 160 may operate as plugs to
close the hole otherwise left open due to the inability of the
valve leaflets to properly coapt. Providing such a surface against
which the mitral valve leaflets may coapt may benefit both patients
having valve leaflets with a reduced range of motion, for example,
due to chordal tethering, and/or patients having leaflets unable to
coapt due to left ventricular dilatation. The plug devices of FIGS.
11a-11f also may enhance coaptation in patients whose leaflets are
misaligned, since each leaflet may coapt with the surface provided
by the plug member independently of the other leaflet.
[0162] Materials suitable for construction of the various plug
devices disclosed herein may be categorized generally into the
following broad groups: synthetic polymers, biological polymers,
metals, ceramics, and engineered tissues. Suitable synthetic
polymers may include flouroethylenes, silicones, urethanes,
poyamides, polyimides, polysulfone, poly-ether ketones, poly-methyl
methacrylates, and other similar materials. Moreover, each of these
compositions potentially may be configured from a variety of
molecular weights or physical conformations.
[0163] Suitable metals may be composed from a variety of
biocompatible elements or alloys. Examples include titanium,
Ti-6AL-4V, stainless steel alloys, chromium alloys, and cobalt
alloys. The stainless steel alloys may include, for example, 304
and 316 stainless steel alloys. The cobalt alloys may include
Elgiloy, MP35N, and Stellite, for example.
[0164] Suitable ceramic materials may be fashioned from pyrolytic
carbon and other diamond-like materials, such as zirconium, for
example. These materials may be applied to a variety of core
materials, such as graphite, for example.
[0165] As for biological materials for manufacturing the devices, a
variety of fixed tissues may be useful in the fabrication process.
Base materials, such as pericardium, facia mater, dura mater, and
vascular tissues may be fixed with a variety of chemical additives,
such as aldehydes and epoxies, for example, so as to render them
nonimmunogenic and biologically stable.
[0166] Tissues also may be engineered to meet the intended purpose.
Substrates may be constructed from a variety of materials, such as
resorbable polymers (e.g., polylactic acid, polyglycolic acid, or
collagen). These materials may be coated with biologically active
molecules to encourage cellular colonization. Additionally, these
tissues may be constructed in vitro, for example using the
patient's own cells or using universal cell lines. In this way, the
tissue may maintain an ability to repair itself or grow with the
patient. This may be particularly advantageous in the case of
pediatric patients, for example.
[0167] Each of the previously mentioned materials also may be
subjected to surface modification techniques, for example, to make
them selectively bioreactive or nonreactive. Such modification may
include physical modification, such as texturing; surface coatings,
including hydrophilic polymers and ceramics (e.g., pyrolytic
carbon, zirconium nitrate, and aluminum oxide); electrical
modification, such as ionic modification, for example; or coating
or impregnation of biologically derived coatings, such as heparin,
albumin, a variety of growth healing modification factors, such as,
for example, vascular endothelial growth factors (VEGF), or other
cytokines.
[0168] The tethers used to suspend the plug members, which will be
described in more detail shortly, may be constructed of either
monofilament or multifilament constructions, such as braids or
cables, for example. Materials such as high strength polymers,
including liquid crystal polymers (Vectran) and ultra high
molecular weight polyethylene fibers (Spectra) may be suitable to
provide desirable mechanical and fatigue properties. Suitable
metals may include stainless steel, titanium alloys, and
cobalt-chrome alloys, for example.
[0169] The materials discussed above are exemplary and not intended
to limit the scope of the invention. Those skilled in the art would
recognize that a variety of other similar suitable materials may be
used for the plug devices and suspension members disclosed
herein.
[0170] The suspended plug members 160a-160f of FIGS. 11a-11f may be
anchored to the heart walls using anchoring members such as, for
example, internal tissue anchors or anchor pads attached externally
of the heart. An example of utilizing external anchor pads for
suspending the plug members 160 within the valve orifice is
illustrated in FIG. 12, which will be explained in more detail
shortly.
[0171] Yet another exemplary embodiment of a plug device is
illustrated in FIGS. 11g(i), 11g(ii). The device of FIGS. 1g(i),
11g(ii) comprises a tubular member 167 that may be at least
partially collapsible and flexible. The top portion of the tubular
member 167 may include a ring structure 168 that may be placed on
the mitral valve annulus. The remaining portions of the tubular
member 167 may be placed through the valve orifice between the
valve leaflets such that the tubular member 167 extends at least
partially into the left ventricular chamber. When pressure in the
left ventricle increases, such as during systole, for example, the
mitral valve leaflets may begin to close. As the leaflets begin to
close, the tubular member 167 collapses, as shown in FIG. 11g(ii),
so as to close the tube 167 at its distal end. This closure closes
the blood flow path between the left atrium and the left ventricle.
Once the pressure in the left atrium again becomes higher than the
pressure in the left ventricle, the tubular member 167 may open to
allow bloodflow therethrough. The tubular plug member 167 itself
therefore provides a type of valving mechanism without the need to
remove the natural valve or provide other mechanical valve
devices.
[0172] Other embodiments of expandable/collapsible plug devices
that operate to perform valving functions are shown in FIGS.
11h-11j. FIGS. 11h(i), 11h(ii) illustrate a collapsible plug member
169 that has a hollow, tapered configuration. During diastole, as
shown in FIG. 11h(i), the plug member 169 has an expanded
configuration so that blood can flow through the plug member 169
and also between the leaflets L and the outer surface of the plug
member 169. The plug member 169 is configured to collapse during
systole, as shown in FIG. 11h(ii), so that the bottom portion 169B
of the plug facing the left ventricle is closed off to prevent
blood flow through the plug 169. In the collapsed configuration,
the member 169 maintains a relatively wide profile at a top portion
169T and tapers toward the bottom portion 169B where the sides of
the plug member 169 come together to close the plug member 169 to
flow therethrough. The tapered sides also allow the valve leaflets
to close against the plug member 169 during systole. In this
manner, blood is substantially prevented from flowing through the
mitral valve during systole.
[0173] FIGS. 11i(i), 11i(ii) show yet another exemplary embodiment
of a collapsible and expandable plug member 170. The plug member
170 includes two wing members 170a, 17b, and an articulation 171
connecting the two wing members 170a, 170b at their top ends.
During systole, as shown in FIG. 11i(i), the pressure in the left
ventricle acts on the wing members 170a, 170b, causing them to
pivot about the articulation 171 in an outward direction (i.e., the
wing members 170a, 170b pivot away from each other). This pivoting
outward of the wing members 170a, 170b allows the wing members
170a, 170b to abut with the valve leaflets L, thus closing the
valve orifice to prevent bloodflow through the valve.
[0174] During diastole, as shown in FIG. 11i(ii), pressure from the
left atrium causes the wing members 170a, 170b to pivot about the
articulation 171 in an inward direction (i.e., the wing members
170a, 170b pivot toward each other). Thus, the wing members 170a,
170b separate from the leaflets L, allowing blood to flow through
the valve from the left atrium into the left ventricle.
[0175] Yet another exemplary embodiment of an expandable and
collapsible plug device is shown in FIGS. 11j(i), 11j(ii). FIG.
11j(i) shows a collapsible plug member 172 during systole and FIG.
11j(ii) shows the collapsible plug device 172 during diastole.
During systole, the plug member 172 essentially is in the form of a
hollow cone with a base of the cone disposed proximate the free
ends of the valve leaflets L. The sides 172a, 172b of the cone take
on a concave configuration during systole, as shown in FIG. 11j(ii)
so as to allow blood to flow between the sides 172a, 172b and the
valve leaflets L. During diastole, the blood flow through the valve
will cause the plug member 172 to expand, thereby billowing the
side walls 172a, 172b outwardly such that they abut the valve
leaflets L to restrict or prevent blood from flowing through the
valve.
[0176] Another exemplary embodiment for a plug device may comprise
a member that is suspended in place below the free edges of the
valve leaflets in a plane substantially parallel to the valve
annulus. Such a plug device is shown in FIG. 11k. In this
embodiment, a piston-like plug device 173 having a disk member 174
suspended on the end of an elongate member 174' is movable along
the longitudinal axis of the valve. The disk member 174, which
preferably has a circular or oval shape, is movable into and out of
contact with the free ends of the valve leaflets L in accordance
with the bloodflow through the heart. In this manner, the
piston-like plug device 173 may operate similar to a one-way check
valve, reducing regurgitation during systole by moving to seal the
free ends of the valve leaflets L with the disk-like member 174, as
shown in FIG. 11k, for example. During diastole, the piston-like
plug device 173 may move in a direction toward the left ventricle
such that the disk member 174 moves out of contact with the free
ends of the valve leaflets L. FIGS. 11l(i), 11l(ii) show an
alternative arrangement of the piston-like plug device 173 of FIG.
11k. In this embodiment, the disk member 174l is made of a flexible
or semi-flexible material. This material may allow the disk member
174l to obtain a reduced cross-sectional profile during diastole,
as shown in FIG. 11l(i), allowing for a relatively normal size
valve orifice blood flow area. During systole, the disk member 174l
expands and inverts as pressure in the left ventricle increases
causing blood to flow toward the valve. The disk member 174l
envelops the ends of the valve leaflets L to substantially prevent
regurgitant bloodflow through the valve, as shown in FIG.
11l(ii).
[0177] Yet another alternative arrangement of a plug device is
shown in FIGS. 11m(i), 11m(ii). In this exemplary embodiment, the
device 175 is implanted such that a disk-like member 176 is
situated substantially above the level of the valve leaflets L
proximate the valve annulus AN. As shown in the FIG. 11m(i), the
perimeter of the disk-like member 176 contacts the upper portions
of the valve leaflets L proximate the valve annulus AN as the
pressure in the left ventricle increases during systole, moving the
valve leaflets L toward one another. This contact facilitates
closure of the mitral valve orifice. On the other hand, during
diastole, as shown in FIG. 11m(ii), the leaflets L move away from
and out of contact with the disk-like member 176, allowing blood to
flow between the disk-like member 176 and the valve leaflets L from
the left atrium LA in to the left ventricle LV.
[0178] The various devices shown in FIGS. 11a-11m(ii) can be
delivered and implanted in the heart using numerous approaches.
FIG. 12 shows one example of an embodiment for implanting a plug
device of the invention, indicated generally as 200, in the heart.
In FIG. 12, the plug member 201 is suspended from at least one
elongate member 202. The elongate member 202 optionally has a
tether-like structure. Anchors 203 are provided on the ends of the
elongate member 202 to secure the device to exterior portions of
the heart wall HW. The anchors 203 optionally may be similar to the
anchors discussed above with reference to FIGS. 4b and 5d, for
example. FIG. 12 shows an exemplary implantation position, namely a
sub-annular position, for the plug device 200 with respect to the
heart.
[0179] Numerous other implantation positions for the plug devices,
discussed above with reference to FIGS. 11a-11m, are envisioned and
are considered within the scope of the invention. Some examples of
these positions are shown in FIGS. 13a-13d. The lines shown in
these figures represent the extension of the elongate member (or
members) 202, from which the plug member is suspended, between the
anchors 203 secured to the exterior portions of the heart wall HW.
FIG. 13a shows a long axis cross-sectional view (from the lateral
side) of the left ventricle LV and left atrium LA. Each of the
positions shown by lines A-D represents anterior-to-posterior
positioning of a plug device. Line A represents a supra-annular,
anterior-to-posterior position; line B represents a sub-annular,
anterior-to-posterior position; line C represents a supra-annular,
anterior to sub-annular, posterior position, and line D represents
a, supra-annular, posterior to sub-annular, anterior position. FIG.
13b shows various lateral-medial positions for a plug device. The
various positions are indicated by lines E-H in FIG. 13b. Line E
represents an intraventricular septum S to sub-annular, lateral
wall LW position; line F represents an intraventricular septum S to
supra-annular, lateral wall LW position; line G represents an
atrial septum AS to supra-annular, lateral wall LW position; and
line H represents an atrial septum AS to sub-annular, lateral wall
LW position. FIG. 13c shows a basal cut-away, cross-sectional view
of the heart with the various positions corresponding to lines A-H
in FIGS. 13a and 13b represented. FIG. 13c also shows two
additional optional positions, indicated by lines I and J, for the
implantation of the plug devices. Line I represents an
anterior-medial, supra-annular atrial wall AW to supra-annular
atrial wall AW position and line J represents an anterior-medial,
supra-annular atrial wall AW to sub-annular atrial wall AW
position. FIG. 13d shows a long-axis cross-sectional view of the
left ventricle LV and left atrium LA with an apical wall APW to
atrial wall AW position, indicated by line K.
[0180] The particular position selected to implant a plug device
may depend on a variety of factors, such as the condition of the
patient's heart, including the heart valves, the delivery technique
utilized to implant the device, the type of plug device utilized to
treat the valve, and other similar factors. Each of the positions
shown in FIGS. 13a-13d, however, permits proper positioning of the
plug device to prevent regurgitation and avoids damage to key
coronary structure. Further, particular positions may be selected
based on factors such as, for example, the geometry, including size
and shape, of the valve orifice.
[0181] The plug devices of FIGS. 11a-11m(ii) may be delivered to
the heart in several ways, including ways that do not require
placing the patient on bypass. Perhaps the most direct approach
includes obtaining open chest access to the left ventricular and
atrial walls. However, the devices also may be implanted using
off-pump surgical techniques or endovascular techniques.
[0182] An example of an approach for delivery of the plug device of
FIG. 12 is illustrated in FIGS. 14a-14c. For exemplary purposes,
the position of the plug device resulting from the delivery shown
in FIGS. 14a-14c corresponds to position B, as shown in FIGS. 13a
and 13c. However, other positions for the plug device could be
obtained using the delivery approach which will now be described.
Moreover, plug devices other than that of FIG. 12 could be
implanted via the delivery techniques to be described.
[0183] In FIG. 14a, a needle and stylet assembly 210 is passed
through the left ventricle LV between the mitral valve leaflets L.
The stylet 211 is then removed, as shown by the arrow in FIG. 14a,
leaving only the hollow needle 212 in place. The position of the
needle 212 between the leaflets L is represented by the label X in
FIG. 14b. The plug device may then be delivered through the needle
212. Or, as shown in FIG. 14c, a leader assembly 213 may be
attached to the elongate member 202 from which the plug member 201
is suspended. The plug member 201 may have a folded configuration
or may be a collapsible and expandable member. A sheath 214 may
retain the plug member 201 during delivery across the heart
chamber. An anchor pad 203 may be attached to the proximal end of
the elongate member 202 during delivery. The anchor pad may
optionally be either fixed at a predetermined position on the
elongate member 202 or it may be movable with respect to the
elongate member 202 so that its position is adjustable. The leader
assembly 213 may be advanced through the heart wall at the side
opposite to the side the needle 212 entered, and the needle 212 may
then be removed from the heart. The leader assembly 213 and the
elongate member 202 may then be advanced further until the plug
member 201 is extracted from the sheath 214. This extraction causes
the plug member 201 to unfold. Once the plug member 201 is fully
extracted from the sheath 214 and appropriately positioned between
the mitral valve leaflets, retaining sheath 214 may be removed from
the heart and the leader assembly removed from the elongate member
202. A second anchor pad 203 may be placed on the distal end of the
elongate member 202 to hold the plug device in place, as shown in
FIG. 12.
[0184] An exemplary embodiment for delivering a plug device using a
retaining sheath is illustrated in FIG. 14d. Elongate member 202
may be connected to a leader member (not shown), which may be in
the form of a sharpened needle, or the like. The leader member is
configured to pass through the heart wall and across the ventricle.
As shown in FIG. 14d, removal of the plug member 201 from the
retaining sheath 214 may occur by advancing the sheath 214
partially through the heart wall HW and pulling the elongate member
202 extending through the heart wall HW opposite to the retaining
sheath 214. As the elongate member 202 is pulled, the plug member
201 advances out of the distal end of the sheath 214. Once the plug
member 201 advances entirely out of the distal end of the sheath
214, it will have an unfolded or expanded configuration and may be
positioned as desired between the mitral valve leaflets L by
pulling on the elongate member (in the direction of the arrow shown
in FIG. 14d).
[0185] FIG. 14e illustrates a top view of an implanted plug device,
including plug member 201, during systole, according to an
exemplary embodiment of the invention. The plug member 201 is
disposed between the valve leaflets L and occupies the position of
the valve opening O through which regurgitant flow would occur in
the absence of valve treatment. FIG. 14f shows a top view of the
implanted plug device during diastole, when the valve leaflets A, P
are opened. As shown, flow through the valve O is permitted in the
orifice space O between the leaflets A, P and the plug member
201.
[0186] FIGS. 15a-15c illustrate another delivery tool that may be
used in lieu of those discussed with reference to FIGS. 14a-14d. In
this embodiment, the elongate member 202, the folded plug member
201, and a deployable anchor member 218 may be retained in a trocar
and needle assembly 216, as shown in FIG. 15a. The assembly 216 may
be inserted across the heart such that it extends out of opposite
heart walls and transverse the mitral valve in any of the positions
discussed with reference to FIGS. 13a-13d, or other suitable,
desired positions. A pusher mechanism 217 may then be inserted
through the proximal end of the trocar and needle assembly 216 to
advance the plug device 200 from the distal end of the assembly
216. As shown in FIG. 15b, an anchor 218 attached to an elongate
member 202 exits the assembly 216 first. The anchor 218 is attached
to the elongate member 202 so as to extend substantially
perpendicularly to the elongate member 202. However, when placed in
the assembly 216, the anchor 218 is turned with respect to the
elongate member 202 such that it lies substantially parallel to the
elongate member 202.
[0187] Once the anchor 218 has advanced out of the assembly 216,
the pusher mechanism may be removed and the assembly 216 and plug
device 200 may be retracted back through the heart in a direction
opposite to the direction of advancement of the assembly 216 into
the heart. As the plug device 200 is retracted with the assembly
216, the anchor 218 will catch on the external surface of the heart
wall, preventing the plug device 200 from being pulled back through
the heart with the assembly 216. The assembly 216 may continue to
be retracted out of the heart and off of the plug device 200 until
the plug member 201 eventually exits the distal end of the assembly
216, as shown in FIG. 15c. Upon exiting the assembly 216, the plug
member 201 unfolds. The plug member 201 may then be positioned
appropriately with respect to the mitral valve and, once the
assembly 216 has been entirely removed from the plug device 200, an
anchor (not shown) may be placed on the free end of the elongate
member opposite to the anchor 218 to secure the plug device 200 in
position.
[0188] Yet another exemplary embodiment of a delivery technique for
a folded plug member is illustrated in FIGS. 16a-16d. In this
embodiment, the plug member 201 may have a folded configuration and
be attached to a plurality of elongate members 202 (e.g., tethers)
for suspending the plug member 201 in the mitral valve orifice
between the leaflets, as described above. These elongate members
202 also assist in the unfolding of the plug member 201. FIG. 16a
depicts the plug device 200 with the plug member 201 in a folded
configuration and attached to four elongate members 202a-202d. The
stylet and needle assembly, and the leader assembly described above
with reference to FIGS. 14a-14c may be used to deliver the plug
device 200 to the valve. In this manner, the elongate members 202a
and 202d may be advanced together through the needle assembly, for
example, in a supra-annular position, as shown in FIG. 16b. Once
advanced, the elongate members 202a and 202d exit one side of the
left atrial wall and the elongate members 202b and 202c exit the
left atrial wall at an opposite side. The plug member 201, still in
a folded configuration, is suspended slightly above the annular
level of the mitral valve MV adjacent the valve orifice.
[0189] To unfold the plug member 201, stylets 14 are attached to
the free ends of the elongate members 202c and 202d. Using the
needle stylets 14 to guide the free ends of the elongate members
202c, 202d, as shown in FIG. 16c, each member 202c, 202d is
advanced back through the heart to an opposite side and to a
sub-annular position, thus exiting through the left ventricular
wall on a side opposite to its original exit through the left
atrial wall. This action causes the plug member 201 to unfold and
extend between the valve leaflets. The elongate members 202a-202d
may then be secured with respect to the heart using external
anchors 203, as shown in FIG. 16d. The plug device 200 in FIG. 16d
thus has a supra-annular, sub-annular position.
[0190] Other techniques for delivery and implantation of the plug
devices of the invention are envisioned and are considered to be
within the scope of the invention. For example, the plug member and
at least one of the anchor members may be inflatable so that during
delivery the members can be in a deflated configuration to
facilitate passage through the heart wall or through a needle. As
shown in FIG. 19, once the plug device 200 (i.e., at least one
anchor and the plug member 202) is placed in the desired position
relative to the mitral valve MV and heart wall HW, an inflator,
which may optionally be in the form of a compressed air device or a
needle 250 (as shown in FIG. 19) containing a fluid, such as PMMA
(polymethylmethacrylate) P-HEMA (poly (2-hydroxyethyl
methacrylate)), for example, may be connected to the elongate
member and used to inflate the plug member 201 and the at least one
anchor member 203. The elongate member in this case would be
configured to allow passage of fluid therethrough to the plug
member and at least one anchor member.
[0191] FIG. 20 illustrates an additional exemplary embodiment of an
inflatable plug device 350. The plug device comprises plug member
351 made of two sheets 351a and 351b attached to each other along
the edges. The plug device 350 also comprises tethers 352, for
example, four tethers 352 attached to the plug member 351 proximate
the corners of the sheets 351a, 351b. At least one of the tethers
352 may define a lumen configured for fluid flow therethrough. The
lumen may be in flow communication with the plug member 351 so as
to permit inflation of the plug member 351 via the lumen. In this
manner, the plug member 351 may be filled to the desired shape and
size as is needed to at least substantially prevent regurgitation
through the valve.
[0192] Endovascular delivery techniques, including, for example,
catheter-based delivery techniques, also are envisioned as within
the scope of the invention. Such endovascular delivery techniques
may be utilized in combination with the methods discussed with
reference to FIGS. 14a-19. For example, the plug devices may be
delivered through a catheter advanced through the lumen of the
aorta AO and across the left atrial chamber LA, as shown in FIG.
17a. Alternatively, as shown in FIG. 17b, the delivery path may be
through the lumen of the coronary sinus CS and the coronary vein
CV, and from the coronary vein CV across the left atrial chamber
LA. Yet another embodiment of an endovascular delivery path is
shown in FIG. 17c. In this figure, the delivery path is through the
lumen of the vena cava CV into the right atrial chamber RA and
across the left atrial chamber LA.
[0193] The techniques for implanting the plug devices discussed
above include extending elongate members, with the plug member
suspended therefrom, substantially transversely from one wall of a
heart chamber to an opposite wall of a heart chamber. In an
alternative embodiment, shown in FIGS. 18a and 18b. The plug member
may be suspended from an elongate member that engages only on one
side of the heart. Such a configuration may alleviate the need to
traverse the entire heart chamber, thereby minimizing risk of
damaging internal cardiac structure.
[0194] FIG. 18a shows an exemplary embodiment of a plug device 230
and anchoring frame 233 for engaging only one side of the heart to
implant the plug device 230. The plug member 201, shown as an
ellipsoid plug member in this figure, depends from a beam member
231 having a horizontally extending portion 231h and a shorter,
vertically extending portion 231v. The plug member 201 is connected
to the vertically extending portion 231v so that the plug member
201 is placed within the valve orifice between the valve leaflets,
as shown in FIG. 18b. Optionally, a intramuscular ingrowth sleeve
232, made of a Dacron velour, for example, may be placed around the
horizontal portion 231h. The function of this sleeve 232 will be
explained with reference to the discussion of the implantation of
the device. The horizontal portion 231h connects to the anchoring
frame 233 at an end opposite to the plug member 201. The anchoring
frame 233 has a substantially I-shaped configuration and the
horizontal portion 231h of the beam member 231 connects to the
vertical leg 233v of the anchoring frame 233.
[0195] The horizontal legs 233h of the anchoring frame are placed
on the external surfaces of the atrial wall and the ventricular
wall, respectively, as shown in FIG. 18b. The vertical leg 233v is
thus spaced from the heart wall. The horizontal legs 233h may be
secured to the heart walls by suturing or other suitable, similar
attachment mechanisms. The horizontal portion 231h of the beam
member 231 extends from the vertical leg 233v and through the
atrial wall so as to suspend the plug member 201 in the appropriate
position relative to the mitral valve MV. The sleeve 232 is
positioned on the horizontal portion 231h, and optionally may be
slidable relative thereto, such that the heart wall surrounds the
sleeve 232. The sleeve 232 therefore provides a surface that
permits ingrowth of the heart wall muscle to assist in stabilizing
the device relative to the heart. The ingrowth of the heart wall
into the sleeve 232 also may prevent damage to the heart wall which
would otherwise occur as a result of relative motion between the
heart wall and the horizontal portion 231h caused by the heart's
beating.
[0196] It will be apparent to those skilled in the art that various
modifications and variations can be made in the devices and related
methods for improving mitral valve function of the present
invention and in construction of such devices without departing
from the scope or spirit of the invention. As an example, a
combination of devices depicted above may be used for achieving
improved mitral valve function. Moreover, although reference has
been made to treating the mitral valve and to the bloodflow
patterns relating to the mitral valve, it is envisioned that other
heart valves may be treated using the devices and methods of the
present invention. Those having skill in the art would recognize
how the devices and methods could be employed and/or modified to
treat valves other than the mitral valve, taking into consideration
factors such as the desired blood flow patterns through the valve.
Other optional embodiments of the invention will be apparent to
those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. The specification
and examples are exemplary only, with a true scope and spirit of
the invention being indicated by the following claims.
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