U.S. patent application number 11/980838 was filed with the patent office on 2008-06-12 for devices, systems, and methods for reshaping a heart valve annulus.
This patent application is currently assigned to Ample Medical, Inc.. Invention is credited to Robert T. Chang, Timothy R. Machold, John A. Macoviak, David A. Rahdert.
Application Number | 20080140188 11/980838 |
Document ID | / |
Family ID | 35428814 |
Filed Date | 2008-06-12 |
United States Patent
Application |
20080140188 |
Kind Code |
A1 |
Rahdert; David A. ; et
al. |
June 12, 2008 |
Devices, systems, and methods for reshaping a heart valve
annulus
Abstract
Devices, systems, and methods employ a heart implant structure
that is sized and configured to be positioned in a left atrium
above the plane of a native mitral heart valve annulus to affect
mitral heart valve function. The implant structure includes a
portion sized and configured to engage a wall of the left atrium
above the plane of the native mitral valve annulus and to extend
across the left atrium along a minor axis of the annulus.
Inventors: |
Rahdert; David A.; (San
Francisco, CA) ; Machold; Timothy R.; (Moss Beach,
CA) ; Macoviak; John A.; (La Jolla, CA) ;
Chang; Robert T.; (Belmont, CA) |
Correspondence
Address: |
Daniel D. Ryan;RYAN KROMHOLZ & MANION, S.C.
Post Office Box 26618
Milwaukee
WI
53226-0618
US
|
Assignee: |
Ample Medical, Inc.
|
Family ID: |
35428814 |
Appl. No.: |
11/980838 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10846850 |
May 14, 2004 |
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11980838 |
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10677104 |
Oct 1, 2003 |
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10846850 |
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Current U.S.
Class: |
623/2.1 ;
623/2.38 |
Current CPC
Class: |
A61F 2210/009 20130101;
A61B 17/00234 20130101; A61B 2017/00783 20130101; A61B 17/0401
20130101; A61B 2017/00876 20130101; A61B 2017/00243 20130101; A61B
2017/0647 20130101; A61B 2017/0437 20130101; A61F 2002/30079
20130101; A61B 17/064 20130101; Y10S 623/904 20130101; A61B
2017/0427 20130101; A61B 2017/0464 20130101; A61F 2/2445 20130101;
A61B 2017/0641 20130101; A61B 2017/0414 20130101; A61B 2017/0412
20130101; A61B 2017/0419 20130101; A61B 2017/0417 20130101; A61B
2017/0496 20130101 |
Class at
Publication: |
623/2.1 ;
623/2.38 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A method comprising providing a heart implant sized and
configured to be positioned in a left atrium above the plane of a
native mitral heart valve annulus to affect mitral heart valve
function, the implant including a first portion sized and
configured to engage a wall of the left atrium above the plane of
the native mitral valve annulus and to extend across the left
atrium along a minor axis of the annulus, the implant including a
second portion sized and configured to extend through a septum to
rest in a right atrium, establishing an intravascular access path
that extends from the right atrium through the septum and into the
left atrium, deploying the implant through the intravascular path
into the left atrium, and positioning the implant with the first
portion engaging a wall of the left atrium above the plane of the
native mitral valve annulus and extending across the left atrium
along a minor axis of the annulus and with the second portion
extending through the septum to rest in the right atrium, such that
the implant affects mitral heart valve function.
2. A method according to claim 1 wherein the implant is positioned
so that the implant changes the shape of the native mitral heart
valve annulus.
3. A method according to claim 1 wherein the implant inwardly
displaces tissue to shorten the minor axis.
4. A heart implant comprising an implant structure sized and
configured to be positioned in a left atrium above the plane of a
native mitral heart valve annulus to affect mitral heart valve
function, the implant structure including a first portion sized and
configured to engage a wall of the left atrium above the plane of
the native mitral valve annulus and to extend across the left
atrium along a minor axis of the annulus, the implant structure
including a second portion sized and configured to extend through a
septum to rest in a right atrium.
5. A heart implant according to claim 4 wherein the implant
structure is sized and configured so that, in use, the implant
structure changes the shape of the native mitral heart valve
annulus.
6. A heart implant according to claim 4 wherein the implant
structure inwardly displaces tissue to shorten the minor axis.
7. A method comprising providing a heart implant sized and
configured to be positioned in a left atrium above the plane of a
native mitral heart valve annulus to affect mitral heart valve
function, the implant including a portion sized and configured to
engage a wall of the left atrium above the plane of the native
mitral valve annulus and to extend across the left atrium along a
minor axis of the annulus, establishing an intravascular access
path that extends from the right atrium through the septum and into
the left atrium, deploying the implant through the intravascular
path into the left atrium, and positioning the implant with the
portion engaging a wall of the left atrium above the plane of the
native mitral valve annulus and extending across the left atrium
along a minor axis of the annulus to affect mitral heart valve
function.
8. A method according to claim 7 wherein the implant is positioned
so that the implant changes the shape of the native mitral heart
valve annulus.
9. A method according to claim 7 wherein the implant inwardly
displaces tissue to shorten the minor axis.
10. A heart implant comprising an implant structure sized and
configured to be positioned in a left atrium above the plane of a
native mitral heart valve annulus to affect mitral heart valve
function, the implant structure including a portion sized and
configured to engage a wall of the left atrium above the plane of
the native mitral valve annulus and to extend across the left
atrium along a minor axis of the annulus.
11. A heart implant according to claim 10 wherein the implant
structure is sized and configured so that, in use, the implant
structure changes the shape of the native mitral heart valve
annulus.
12. A heart implant according to claim 10 wherein the implant
structure inwardly displaces tissue to shorten the minor axis.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 10/846,850, filed May 14, 2004, which is a
continuation-in-part of U.S. patent application Ser. No.
10/677,104, filed Oct. 1, 2003, and entitled "Devices, Systems, and
Methods for Reshaping a Heart Valve Annulus," which claims the
benefit of U.S. patent application Ser. No. 09/666,617, filed Sep.
20, 2000 and entitled "Heart Valve Annulus Device and Methods of
Using Same," which is incorporated herein by reference. This
application also claims the benefit of Patent Cooperation Treaty
Application Serial No. PCT/US 02/31376, filed Oct. 1, 2002 and
entitled "Systems and Devices for Heart Valve Treatments," which
claimed the benefit of U.S. Provisional Patent Application Ser. No.
60/326,590, filed Oct. 1, 2001, which are incorporated herein by
reference. This application also claims the benefit of U.S.
Provisional Application Ser. No. 60/429,444, filed Nov. 26, 2002,
and entitled "Heart Valve Remodeling Devices;" U.S. Provisional
Patent Application Ser. No. 60/429,709, filed Nov. 26, 2002, and
entitled "Neo-Leaflet Medical Devices;" and U.S. Provisional Patent
Application Ser. No. 60/429,462, filed Nov. 26, 2002, and entitled
"Heart Valve Leaflet Retaining Devices," which are each
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention is directed to devices, systems, and methods
for improving the function of a heart valve, e.g., in the treatment
of mitral valve regurgitation.
BACKGROUND OF THE INVENTION
I. The Anatomy of a Healthy Heart
[0003] The heart (see FIG. 1) is slightly larger than a clenched
fist. It is a double (left and right side), self-adjusting muscular
pump, the parts of which work in unison to propel blood to all
parts of the body. The right side of the heart receives poorly
oxygenated ("venous") blood from the body from the superior vena
cava and inferior vena cava and pumps it through the pulmonary
artery to the lungs for oxygenation. The left side receives
well-oxygenation ("arterial") blood from the lungs through the
pulmonary veins and pumps it into the aorta for distribution to the
body.
[0004] The heart has four chambers, two on each side--the right and
left atria, and the right and left ventricles. The atria are the
blood-receiving chambers, which pump blood into the ventricles. A
wall composed of membranous and muscular parts, called the
interatrial septum, separates the right and left atria. The
ventricles are the blood-discharging chambers. A wall composed of
membranous and muscular parts, called the interventricular septum
separates the right and left ventricles.
[0005] The synchronous pumping actions of the left and right sides
of the heart constitute the cardiac cycle. The cycle begins with a
period of ventricular relaxation, called ventricular diastole. The
cycle ends with a period of ventricular contraction, called
ventricular systole.
[0006] The heart has four valves (see FIGS. 2 and 3) that ensure
that blood does not flow in the wrong direction during the cardiac
cycle; that is, to ensure that the blood does not back flow from
the ventricles into the corresponding atria, or back flow from the
arteries into the corresponding ventricles. The valve between the
left atrium and the left ventricle is the mitral valve. The valve
between the right atrium and the right ventricle is the tricuspid
valve. The pulmonary valve is at the opening of the pulmonary
artery. The aortic valve is at the opening of the aorta.
[0007] At the beginning of ventricular diastole (i.e., ventricular
filling) (see FIG. 2), the aortic and pulmonary valves are closed
to prevent back flow from the arteries into the ventricles. Shortly
thereafter, the tricuspid and mitral valves open (as FIG. 2 shows),
to allow flow from the atria into the corresponding ventricles.
Shortly after ventricular systole (i.e., ventricular emptying)
begins, the tricuspid and mitral valves close (see FIG. 3)--to
prevent back flow from the ventricles into the corresponding
atria--and the aortic and pulmonary valves open--to permit
discharge of blood into the arteries from the corresponding
ventricles.
[0008] The opening and closing of heart valves occur primarily as a
result of pressure differences. For example, the opening and
closing of the mitral valve occurs as a result of the pressure
differences between the left atrium and the left ventricle. During
ventricular diastole, when ventricles are relaxed, the venous
return of blood from the pulmonary veins into the left atrium
causes the pressure in the atrium to exceed that in the ventricle.
As a result, the mitral valve opens, allowing blood to enter the
ventricle. As the ventricle contracts during ventricular systole,
the intraventricular pressure rises above the pressure in the
atrium and pushes the mitral valve shut.
[0009] The mitral and tricuspid valves are defined by fibrous rings
of collagen, each called an annulus, which forms a part of the
fibrous skeleton of the heart. The annulus provides attachments for
the two cusps or leaflets of the mitral valve (called the anterior
and posterior cusps) and the three cusps or leaflets of the
tricuspid valve. The leaflets receive chordae tendineae from more
than one papillary muscle. In a healthy heart, these muscles and
their tendinous cords support the mitral and tricuspid valves,
allowing the leaflets to resist the high pressure developed during
contractions (pumping) of the left and right ventricles.
[0010] In a healthy heart, the chordae tendineae become taut,
preventing the leaflets from being forced into the left or right
atria and everted. Prolapse is a term used to describe this
condition. This is normally prevented by contraction of the
papillary muscles within the ventricle, which are connected to the
mitral valve leaflets by the chordae tendineae. Contraction of the
papillary muscles is simultaneous with the contraction of the
ventricle and serves to keep healthy valve leaflets tightly shut at
peak contraction pressures exerted by the ventricle.
II. Characteristics and Causes of Mitral Valve Dysfunction
[0011] In a healthy heart (see FIG. 4), the dimensions of the
mitral valve annulus create an anatomic shape and tension such that
the leaflets coapt, forming a tight junction, at peak contraction
pressures. Where the leaflets coapt at the opposing medial and
lateral sides of the annulus are called the leaflet commissures,
and are designated in FIG. 4 and in other Figures as CM (denoting
the medial commissure) and CL (denoting the lateral
commissure).
[0012] Valve malfunction can result from the chordae tendineae (the
chords) becoming stretched, and in some cases tearing. When a chord
tears, the result is a leaflet that flails. Also, a normally
structured valve may not function properly because of an
enlargement of or shape change in the valve annulus. This condition
is referred to as a dilation of the annulus and generally results
from heart muscle failure. In addition, the valve may be defective
at birth or because of an acquired disease.
[0013] Regardless of the cause (see FIG. 5), mitral valve
dysfunction can occur when the leaflets do not coapt at peak
contraction pressures. As FIG. 5 shows, the coaptation line of the
two leaflets is not tight at ventricular systole. As a result, an
undesired back flow of blood from the left ventricle into the left
atrium can occur. This condition is called regurgitation.
[0014] In some cases (see FIG. 6), the leaflets do not form a tight
coaptation junction because the dimensions of the mitral valve
annulus, measured along the major axis from commissure to
commissure--CM to CL--and/or measured along the minor axis anterior
to posterior--A to P--change. The changed dimensions no longer
create the anatomic shape and tension in which the leaflets coapt
at peak contraction pressures.
[0015] Comparing a healthy annulus in FIG. 4 to an unhealthy
annulus in FIG. 6, the unhealthy annulus is dilated and, in
particular, the anterior-to-posterior distance along the minor axis
is increased. As a result, the shape and tension defined by the
annulus becomes less oval (see FIG. 4) and more round (see FIG. 6).
This condition is called dilation. When the annulus is dilated, the
shape and tension conducive for coaptation at peak contraction
pressures progressively deteriorate. Instead, at peak contraction
pressures, the leaflets do not coapt completely, and a gap forms
between the leaflets. During ventricular systole, regurgitation can
occur through this gap. It is believed that the ratio between the
commissure-to-commissure distance along the major axis and
anterior-to-posterior distance along the minor axis bears a
relationship to the effectiveness of leaflet coaptation. If the
anterior-to-posterior distance along the minor axis increases, the
ratio changes, and when the ratio reaches a certain value,
regurgitation or the likelihood of regurgitation is indicated.
[0016] As a result of regurgitation, "extra" blood back flows into
the left atrium. During subsequent ventricular diastole (when the
heart relaxes), this "extra" blood returns to the left ventricle,
creating a volume overload, i.e., too much blood in the left
ventricle. During subsequent ventricular systole (when the heart
contracts), there is more blood in the ventricle than expected.
This means that: (1) the heart must pump harder to move the extra
blood; (2) too little blood may move from the heart to the rest of
the body; and (3) over time, the left ventricle may begin to
stretch and enlarge to accommodate the larger volume of blood, and
the left ventricle may become weaker.
[0017] Although mild cases of mitral valve regurgitation result in
few problems, more severe and chronic cases eventually weaken the
heart and can result in heart failure. Mitral valve regurgitation
can be an acute or chronic condition. It is sometimes called mitral
insufficiency.
III. Prior Treatment Modalities
[0018] In the treatment of mitral valve regurgitation, diuretics
and/or vasodilators can be used to help reduce the amount of blood
flowing back into the left atrium. An intra-aortic balloon
counterpulsation device is used if the condition is not stabilized
with medications. For chronic or acute mitral valve regurgitation,
surgery to repair or replace the mitral valve is often
necessary.
[0019] To date, invasive, open heart surgical approaches have been
used to repair mitral valve dysfunction. During these surgical
repair procedures, efforts are made to cinch or resect portions
and/or fix in position large portions of the dilated annulus.
During these surgical repair procedures, the annulus can be
reshaped with annular or peri-annular rings or similar ring-like
devices. The repair devices are typically secured to the annulus
and surrounding tissue with suture-based fixation. The repair
devices extend over the top and over much or all of the
circumference of the annulus and leaflet surfaces.
[0020] A physician may decide to replace an unhealthy mitral valve
rather than repair it. Invasive, open heart surgical approaches are
used to replace the natural valve with either a mechanical valve or
biological tissue (bioprosthetic) taken from pigs, cows, or
horses.
[0021] The need remains for simple, cost-effective, and less
invasive devices, systems, and methods for treating dysfunction of
a heart valve, e.g., in the treatment of mitral valve
regurgitation.
SUMMARY OF THE INVENTION
[0022] The invention provides devices, systems, and methods that
employ an implant sized and configured to attach, at least in part,
in, on, or near the annulus of a dysfunctional heart valve. In use,
the implant extends either across the minor axis of the annulus to
shorten the minor axis, or across the major axis of the annulus to
lengthen the major axis, or both. The implant restores to the heart
valve annulus and leaflets a more functional anatomic shape and
tension. The more functional anatomic shape and tension are
conducive to coaptation of the leaflets, which, in turn, reduces
retrograde flow or regurgitation.
[0023] One aspect of the invention provides devices, systems, and
methods that include a heart implant structure that is sized and
configured to be positioned in a left atrium above the plane of a
native mitral heart valve annulus to affect mitral heart valve
function. The implant structure includes a portion sized and
configured to engage a wall of the left atrium above the plane of
the native mitral valve annulus and to extend across the left
atrium along a minor axis of the annulus.
[0024] Another aspect of the invention provides devices, systems,
and methods that include an implant structure sized and configured
to be positioned in a left atrium above the plane of a native
mitral heart valve annulus to affect mitral heart valve function.
The implant structure includes a first portion sized and configured
to engage a wall of the left atrium above the plane of the native
mitral valve annulus and to extend across the left atrium along a
minor axis of the annulus. The implant structure also includes a
second portion sized and configured to extend through a septum to
rest in a right atrium.
[0025] In one embodiment, the implant structure is sized and
configured so that, in use, the implant structure changes the shape
of the native mitral heart valve annulus.
[0026] In one embodiment, the implant structure inwardly displaces
tissue to shorten the minor axis.
[0027] Other features and advantages of the invention shall be
apparent based upon the accompanying description, drawings, and
claims.
DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a perspective, anterior anatomic view of the
interior of a healthy heart.
[0029] FIG. 2 is a superior anatomic view of the interior of a
healthy heart, with the atria removed, showing the condition of the
heart valves during ventricular diastole.
[0030] FIG. 3 is a superior anatomic view of the interior of a
healthy heart, with the atria removed, showing the condition of the
heart valves during ventricular systole.
[0031] FIG. 4 is a superior anatomic view of a healthy mitral valve
during ventricular systole, showing the leaflets properly
coapting.
[0032] FIG. 5 is a superior anatomic view of the interior of a
heart, with the atria removed, showing the condition of the heart
valves during ventricular systole, and further showing a
dysfunctional mitral valve in which the leaflets are not properly
coapting, causing regurgitation.
[0033] FIG. 6 is a superior anatomic view of a disfunctional mitral
valve during ventricular systole, showing that the leaflets are not
properly coapting, causing regurgitation.
[0034] FIGS. 7A and 7B are side perspective views of implants sized
and configured to rest at or near a heart valve annulus and apply a
direct mechanical force along the minor axis of the annulus to
inwardly displace tissue toward the center of the annulus, the
implant shown in FIG. 7A being configured to extend significantly
above the plane of the valve, and the implant shown in FIG. 7B
being configured to extend a short distance above the plane of the
valve.
[0035] FIG. 8 is a lateral perspective view of the implant shown in
FIG. 7A deployed at or near the mitral valve annulus in the left
atrium.
[0036] FIG. 9 is a superior view of the implant and heart shown in
FIG. 8.
[0037] FIGS. 10A. 10B, and 10C are perspective anterior views of
the intravascular deployment of a catheter from the right atrium
across the septum into the left atrium for the purpose of
implanting an implant of the type shown in FIG. 7A.
[0038] FIGS. 11A, 11B, and 11C are lateral perspective views of the
sequential deployment of the implant shown in FIG. 7A from the
catheter shown in FIGS. 10A, 10B, and 10C in the left atrium, with
a balloon being shown in FIG. 11C inflated to place the implant
into tension across the minor axis of the mitral valve.
[0039] FIG. 12 is a side perspective view of an alternative
embodiment of an implant sized and configured to rest at or near a
heart valve annulus and apply a direct mechanical force along the
minor axis of the annulus to inwardly displace tissue toward the
center of the annulus, the implant shown in FIG. 12 including
bell-shaped protrusions that can be grasped to aid in the
positioning and/or tensioning of the implant.
[0040] FIG. 13 is a lateral perspective view of the implant shown
in FIG. 12 deployed at or near the mitral valve annulus in the left
atrium, with one of the bell-shaped protrusions extending through
and anchored to the septum in the right atrium.
[0041] FIG. 14 is a side view of an alternative embodiment of an
implant sized and configured to rest at or near a heart valve
annulus and apply a direct mechanical force along the minor axis of
the annulus to inwardly displace tissue toward the center of the
annulus, the implant shown in FIG. 14 having an anterior component
that is sized and configured to pass through the septum and project
into the right atrium.
[0042] FIG. 15 is a lateral perspective view of a pair of the
implants shown in FIG. 14 deployed at or near the mitral valve
annulus in the left atrium, with the anterior component extending
through and anchored to the septem in the right atrium.
[0043] FIG. 16 is a superior view of the implants and the heart
shown in FIG. 15.
[0044] FIGS. 17A and 17B are lateral side views of the deployment
of one of the implants shown in FIGS. 15 and 16 from the right
atrium and through the septum into the left atrium.
[0045] FIGS. 18A and 18B are superior views of a mitral valve
annulus having different embodiments of magnetic force systems
implanted at or near the annulus, to generate a magnetic field that
attract tissue regions of the annulus toward one another, the
magnetic force systems being arranged to shorten the minor axis of
the annulus.
[0046] FIG. 18C is an anterior side view of the magnetic force
systems shown in FIGS. 18A and 18B.
[0047] FIGS. 19A and 19B are superior views of a mitral valve
annulus with other alternative embodiments of implanted magnetic
force systems of the types shown in FIGS. 18A, 18B, and 18C
implanted at or near the annulus, to generate a magnetic field that
attract tissue regions of the annulus toward one another to shorten
the minor axis of the annulus.
[0048] FIG. 20 is a superior view of a mitral valve annulus with an
alternative embodiment of an implanted magnetic force system
implanted at or near the annulus along one side of the annulus, to
generate a magnetic field that attract tissue regions along that
side of the annulus toward one another.
[0049] FIG. 21 is a representative embodiment of button-shaped
magnetic elements that can be used to create the magnetic force
systems shown in FIGS. 18A, 18B, 18C, 19A, 19B, and 20.
[0050] FIG. 22 is a side section view of a button-shaped magnetic
element taken generally along line 22-22 is FIG. 21.
[0051] FIGS. 23A and 23B are a representative embodiment of a
button-shaped magnetic element that can be used to create the
magnetic force systems shown in FIGS. 18A, 18B, 18C, 19A, 19B, and
20, the magnetic element including a leaflet retaining appendage
that overlays a native valve leaflet, FIG. 23A being a side
perspective view and FIG. 23B being a side section view of the
magnetic element and appendage.
[0052] FIG. 24 is a superior view of a mitral valve with the
magnetic elements shown in FIGS. 23A and 23B implanted along
opposite anterior and posterior sides of the annulus.
[0053] FIG. 25 is a superior view of a heart showing the presence
of a magnetic force system having one magnetic element implanted
within the coronary sinus above the posterior annulus of the mitral
valve and a second magnetic element implanted on the septum in the
right atrium close to the anterior annulus of the mitral valve, to
create between them a force of magnetic attraction that shortens
the minor axis of the mitral valve.
[0054] FIG. 26 is a lateral perspective view of the left atrium
showing the implantation at or near a mitral valve of an implant
along the major axis and an implant along the minor axis, forming a
combined implant system that can concurrently lengthen the major
axis and shorten the minor axis.
[0055] FIG. 27 is a superior view of the combined implant system
and heart shown in FIG. 26.
[0056] FIG. 28 is a side view of a representative embodiment of an
implant that can be implanted along the major axis of a valve
annulus in association with the system shown in FIGS. 26 and 27,
the implant being sized to apply a direct mechanical force along
the major axis of the annulus to lengthen the major axis.
[0057] FIG. 29 is a side perspective view of an alternative
embodiment of an implant that can be implanted along the major axis
of a valve annulus in association with the system shown in FIGS. 26
and 27.
[0058] FIG. 30 is a lateral perspective view showing the implant
shown in FIG. 29 implanted along the major axis of a mitral valve
within the left atrium.
[0059] FIG. 31 is a side perspective view of a multiple function
implant that is sized and configured to rest about a valve annulus
to concurrently reshape the valve annulus along both major and
minor axes, the implant in FIG. 31 having barbs that can be placed
into contact with tissue at or near the annulus.
[0060] FIG. 32 is a lateral perspective view showing the implant
shown in FIG. 31 implanted about a mitral valve within the left
atrium.
[0061] FIG. 33 is a side perspective view of an alternative
embodiment of a multiple function implant that is sized and
configured to rest about a valve annulus to concurrently reshape
the valve annulus along both major and minor axes, the implant in
FIG. 35 having inwardly folded barbs that can be outwardly folded
by expansion of the implant into contact with tissue at or near the
annulus.
[0062] FIGS. 34, 35, and 36 are superior views of the outwardly
folding of the barbs of the implant shown in FIG. 33 in response to
the inflation of a balloon.
[0063] FIG. 37 is a lateral perspective view showing the implant
shown in FIG. 33 implanted about a mitral valve within the left
atrium.
[0064] FIGS. 38A, 38B, and 38C are lateral perspective views of the
sequential deployment of the implant shown in FIG. 28 from the
catheter shown in FIGS. 10A, 10B, and 10C, the implant being
deployed in compression across the major axis of the mitral valve
in the left atrium.
[0065] FIG. 39 is a side perspective view of an alternative
embodiment of an implant that can be implanted along the major axis
of a valve annulus in association with the system shown in FIGS. 26
and 27, the implant being sized and configured to rest at or near a
heart valve annulus and apply a direct mechanical force along the
major axis of the annulus to outwardly displace tissue away from
the center of the annulus, the implant shown in FIG. 39 including
bell-shaped protrusions that can be grasped to aid in the
positioning and/or placement of the implant into compression.
[0066] FIG. 40 is a lateral perspective view of the implant shown
in FIG. 39 deployed at or near the mitral valve annulus in the left
atrium, with one of the bell-shaped protrusions extending through
and anchored to the septum in the right atrium.
[0067] FIG. 41 is a lateral perspective view of a combined implant
system of the type shown in FIG. 26 that can concurrently lengthen
the major axis and shorten the minor axis, the system including a
major axis implant and a minor axis implant both of which include a
bell-shaped protrusion that extends through and is anchored to the
septum in the right atrium.
[0068] FIG. 42 is a side perspective view of an alternative
embodiment of a multiple function implant that is sized and
configured to rest about a valve annulus to concurrently reshape
the valve annulus along both major and minor axes, the implant in
FIG. 42 having a major axis component that comprises an elastic
member of the type shown in FIG. 28 and a minor axis component that
comprises a magnetic force system of the type shown in FIG.
18A.
[0069] FIG. 43 is a superior section view of a heart showing the
installation of a point loaded annuloplasty system about the mitral
valve annulus.
[0070] FIGS. 44A, 44B, and 44C are perspective views of
representative embodiments of clip components that accommodate
passage of an elastic frame to create the point loaded annuloplasty
system shown in FIG. 43.
[0071] FIG. 45 is a superior section view of a heart showing the
installation of an alternative embodiment of a point loaded
annuloplasty system about the mitral valve annulus, the system
shown in FIG. 45 having a point attachment in the right atrium
across the septum.
[0072] FIG. 46 is a perspective view of an implant sized and
configured to perform commissural annuloplasty at or near the
mitral valve in the left atrium, the implant having elastic jaws
that squeeze the annulus together at the commissures to promote
leaflet coaptation.
[0073] FIG. 47 is a lateral perspective view of the left atrium,
showing the placement of the implant shown in FIG. 46 in the mitral
valve to perform commissural annuloplasty.
[0074] FIGS. 48A and 48B are enlarged superior views of the elastic
jaws that the implant shown in FIG. 46 includes to create pulling
forces at a commissure, FIG. 48A showing the jaws spread apart to
engage tissue at or near a commissure, and FIG. 48B showing the jaw
in an in-tension condition to squeeze the annulus together at the
commissure to promote leaflet coaptation.
[0075] FIG. 49 shows an anterior perspective view of a mitral valve
in which a structural variation of the implant shown in FIG. 46 has
been implanted, the structural variation having elastic jaws that
have been lengthened and shaped to follow the medial and lateral
contours of the annulus to be placed into tension across the minor
axis of the annulus to provide a mechanical force that shortens the
minor axis in the manner shown in FIG. 9.
[0076] FIG. 50 shows a perspective view of a variation of the
implant shown in FIG. 46, which includes a ring-like structure that
carries magnetic elements, to provide a magnetic force that
shortens the minor axis in the manner shown in FIG. 18A.
DETAILED DESCRIPTION
[0077] Although the disclosure hereof is detailed and exact to
enable those skilled in the art to practice the invention, the
physical embodiments herein disclosed merely exemplify the
invention, which may be embodied in other specific structure. While
the preferred embodiment has been described, the details may be
changed without departing from the invention, which is defined by
the claims.
I. Implants for Direct Shortening of the Minor Axis of a Heart
Valve Annulus
[0078] A. Intra-Atrial Implants
[0079] 1. Structure
[0080] FIGS. 7A and 7B show embodiments of implants 10 sized and
configured to rest at or near a heart valve annulus. In FIGS. 8 and
9, the embodiment of the implant 10 of FIG. 7A is shown resting in
a mitral valve. In this arrangement (as FIGS. 8 and 9 show), the
implant 10 extends along the minor axis (i.e., across the valve
annulus in an anterior-to-posterior direction).
[0081] As FIGS. 8 and 9 show, the implant 10 is sized and shaped so
that, in use, it applies a direct mechanical force along the minor
axis of the annulus. The direct mechanical force serves to inwardly
displace tissue (i.e., to displace tissue toward the center of the
annulus) to reshape the annulus. In the illustrated embodiment
(i.e., the mitral valve), the mechanical force serves to shorten
the minor axis of the annulus. In doing so, the implant 10 can also
reactively reshape the annulus along its major axis and/or
reactively reshape other surrounding anatomic structures.
[0082] It should be appreciated that, when situated in other valve
structures, the axes affected may not be the "major" and "minor"
axes, due to the surrounding anatomy. It should also be appreciated
that, in order to be therapeutic, the implant may only need to
reshape the annulus during a portion of the heart cycle, such as
during ventricular systolic contraction. For example, the implant
may be sized to produce small or negligible displacement of the
annulus to restore or enhance inward movement of the annulus during
ventricular diastolic contraction.
[0083] The mechanical force applied by the implant 10 across the
minor axis can restore to the heart valve annulus and leaflets a
more normal anatomic shape and tension (see FIGS. 8 and 9). The
more normal anatomic shape and tension are conducive to coaptation
of the leaflets during ventricular systole, which, in turn, reduces
regurgitation.
[0084] In its most basic form, the implant 10 is made--e.g., by
bending, shaping, joining, machining, molding, or extrusion--from a
biocompatible metallic or polymer material, or a metallic or
polymer material that is suitably coated, impregnated, or otherwise
treated with a material to impart biocompatibility, or a
combination of such materials. The material is also desirably
radio-opaque or incorporates radio-opaque features to facilitate
fluoroscopic visualization.
[0085] As FIGS. 7A and 7B show, the implant 10 includes a pair of
struts 12 joined by an intermediate rail 14. As FIG. 8 shows, the
struts 12 are sized and configured to engage tissue at either an
infra-annular position (i.e., engaging the fibrous body of the
annulus) or a supra-annular position (i.e., engaging atrial tissue
above or near the annulus). The rail 14 spans the struts 12. The
rail 14 (like the struts 12) can take various shapes and have
various cross-sectional geometries. The rail 14 (and/or the struts
12) can have, e.g., a generally curvilinear (i.e., round or oval)
cross section, or a generally rectilinear cross section (i.e.,
square or rectangular), or combinations thereof. In the embodiment
shown in FIGS. 7A and 8, the rail 14 of the implant 10 is
configured to extend significantly above the plane of the valve
toward the dome of the left atrium. In the embodiment shown in FIG.
7B, the rail 14 of the implant 10 is configured to not extend
significantly above the plane of the valve, but extend only enough
to avoid interference with the valve leaflets.
[0086] The struts 12 each include one or more fixation elements 16.
A given fixation element 16 is sized and configured to take
purchase in tissue in either the infra-annular or supra-annular
position. The fixation element 16 desirably relies at least partly
on the valve annulus and/or neighboring anatomic structures to
anchor and fix the position of the implant and resist its migration
out of the annulus.
[0087] In FIG. 7, the fixation element 16 comprises an array of
barbs that penetrate tissue. FIGS. 12 and 13 (which will be
described in greater detail later) show another representative
embodiment for a fixation element 16, which comprises an array of
tines that may contain secondary barbs in a direction that
facilitates griping the tissue. Other types and forms of tissue
fixation elements 16 can be used, e.g., pads with or without tissue
penetrating members, and/or roughened surfaces and/or tissue
in-growth promoting materials, such as polyester fabric. Any
fixation element 16 may, if desired, be combined with suture, an
adhesive, or like material to further secure the implant.
[0088] Being free of an appendage that extends beneath the annulus,
adjustment of implant position after or during implantation is
facilitated. The implant 10 also presents less chance of trauma or
damage to tissue and anatomic structures beneath the annulus.
[0089] As shown in FIGS. 7 to 9, the implant 10 is desirably
"elastic." The rail 14 is sized and configured to possess a normal,
unloaded, shape or condition (shown in FIG. 7). In this condition,
the rail 14 is not in compression or tension, and the struts 12 are
spaced apart closer than the anterior-to-posterior dimension of the
minor axis of the targeted heart valve annulus. The material of the
implant 10 is selected to possess a desired spring constant. The
spring constant imparts to the rail 14 the ability to be
elastically spread apart and placed in tension out of its normal,
unloaded condition, in response to external stretching forces
applied at the struts.
[0090] When the struts 12 are stretched apart and anchored in
tissue at or near the annulus (see FIGS. 8 and 9), the rail 14
assumes an elastically loaded, in-tension condition. When in its
elastically loaded, in-tension condition, the rail 14 exerts,
through the struts 12 and fixation element 16, opposing pulling
forces on tissues at or near the annulus. These forces are shown by
arrows marked PF in FIGS. 8 and 9. The pulling forces inwardly
displace tissue and shorten the annulus along its minor axis. The
pulling forces can also reshape the major axis and/or surrounding
anatomic structures. In this way, the implant 10 can reshape the
valve annulus toward a shape more conducive to leaflet
coaptation.
[0091] An elastic implant as described can be made, e.g., from
superelastic alloy, like Nitinol material. In this arrangement, the
implant can also be elastically straightened and/or folded to fit
within a catheter or sheath during deployment, and will regain a
preferred shape upon deployment.
[0092] The spring constant of the implant 10 may be selected to be
greater than the spring constant of adjoining tissue.
Alternatively, the spring constant of the implant 10 may be
selected to approximate the spring constant of adjoining tissue,
thereby providing compliance to allow the implant 10 to adapt to
tissue morphology during use. The spring constant of the implant 10
may vary along the length of the rail 14, so that some portions of
the rail 14 are stiffer or more compliant than other portions of
the rail 14.
[0093] 2. Implantation
[0094] The implant 10 as just described and shown in either FIG. 7A
or 7B lends itself to implantation in a heart valve annulus in
various ways. The implant 10 can be implanted, e.g., in an open
heart surgical procedure. Alternatively, the implant 10 can be
implanted using catheter-based technology via a peripheral venous
access site, such as in the femoral or jugular vein or femoral
artery, under image guidance. Alternatively, the implant 10 can be
implanted using thoracoscopic means through the chest, or by means
of other surgical access through the right atrium, also under image
guidance. Image guidance includes but is not limited to
fluoroscopy, ultrasound, magnetic resonance, computed tomography,
or combinations thereof.
[0095] FIGS. 10 and 11 show a representative embodiment of the
deployment of an elastic implant 10 of the type shown in FIGS. 7A,
8, and 9 by a percutaneous, catheter-based procedure, under image
guidance.
[0096] Percutaneous vascular access is achieved by conventional
methods into the femoral or jugular vein. As FIG. 10A shows, under
image guidance, a catheter 52 is steered through the vasculature
into the right atrium. A needle cannula 54 carried on the distal
end of the catheter is deployed to pierce the septum between the
right and left atrium. As FIG. 10B shows, a guide wire 56 is
advanced trans-septally through the needle catheter 52 into the
left atrium. The first catheter 52 is withdrawn (as FIG. 10C
shows), and under image guidance, an implant delivery catheter 58
is advanced over the guide wire 56 into the left atrium into
proximity with the mitral valve. Alternatively, the implant
delivery catheter 58 can be deployed trans-septally by means of
surgical access through the right atrium.
[0097] The implant delivery catheter 58 carries a sheath 60 at its
distal end (see FIG. 10C). The implant 10 is constrained in a
collapsed, straightened condition within the sheath. The sheath 60
is sized and configured to be withdrawn (e.g., by sliding it
proximally), to progressively free the implant 10. Progressively
freed from the sheath 60, the elastic implant 10 will expand and
take shape. Alternatively, a flexible push rod in the catheter 58
can be used to expel the implant 10 from the sheath 60, with the
same result.
[0098] Desirably, the struts 12 are folded within the sheath 60 to
reduce the collapsed profile and facilitate the expansion of the
implant 10 once free of the sheath 60. As FIG. 11A shows, under
image guidance, the strut 12 on the posterior end of the implant 10
is first freed from the sheath 60. The posterior strut 12 is
manipulated to place the fixation element 16 into tissue in or near
the posterior annulus. As FIG. 11B shows, the delivery catheter 58
maintains force on the posterior strut 12, as the sheath 60 is
further withdrawn, as the catheter tracks across the minor axis of
the annulus in a posterior-to-anterior direction. The delivery
catheter 58 may be sized and configured to have the column strength
sufficient to maintain force on the posterior strut. Progressively
freed from the sheath 60, the elastic implant 10 takes shape (see
FIG. 11C), until the anterior strut 12 unfolds. The rail 14 can be
placed into tension, e.g., using a balloon B and/or
catheter-deployed grasping instruments, to seat the fixation
element 16 of the anterior strut 12 in tissue at or near the
anterior annulus. Once seated, the strut 12 is released by the
catheter 58.
[0099] In an alternative embodiment (see FIG. 12), the implant 10
includes bell-shaped protrusions 20 and 22 formed, respectively,
along anterior and posterior portions of the rail 14. As FIG. 13
shows, the anterior protrusion 20 is sized and configured to, when
implanted, extend through the septum and project into the right
atrium. There, the anterior protrusion 20 is exposed for
manipulation by a suitable grasping instrument deployed in the
right atrium. For example, the grasping instrument can take hold of
the protrusion 20 in the right atrium to facilitate placement of
the rail 14 in tension within the left atrium. The posterior
protrusion 22 within the left atrium can also be grasped by an
instrument in the left atrium, to aid in positioning and/or for
tensioning the rail.
[0100] As FIG. 13 shows, barbed stays 24 braced against the septum
can be crimped to the anterior protrusion 20, to help maintain a
desired degree of tension on the rail 14 in the left atrium.
[0101] Furthermore, the projection of the anterior protrusion 20
into the right atrium facilitates repositioning and/or retrieval of
the implant 10 from the right atrium, when desired.
[0102] B. Trans-Septal Implants
[0103] 1. Structure
[0104] FIG. 14 shows another embodiment of an implant 26, which is
sized and configured to apply a mechanical force along the minor
axis of a heart valve, or to otherwise stabilize tissue adjacent a
heart valve annulus, and, in particular, a mitral heart valve
annulus, as FIGS. 15 and 16 show. In the illustrated embodiment,
and as described in connection with the implant 10 shown in FIG. 7,
the mechanical force that is applied by the implant 26 in FIGS. 15
and 16 (shown by arrows) serves to inwardly displace tissue (i.e.,
to displace tissue toward the center of the annulus) (see FIGS. 15
and 16), to shorten the minor axis and reshape the valve. As
previously described, the mechanical force directly applied by the
implant 26 across the minor axis can also reactively reshape the
major axis of the annulus as well as reshape other surrounding
anatomic structures. The implant 26 can restore the heart valve
annulus and leaflets to a more normal anatomic shape and tension
conducive to coaptation of the leaflets during ventricular systole,
which, in turn, reduces regurgitation. It should be appreciated,
however, the presence of the implant 26 may serve to stabilize
tissue adjacent the heart valve annulus, without affecting the
length of the minor axis.
[0105] As shown in FIG. 14, the implant 26 is made--e.g., by
bending, shaping, joining, machining, molding, or extrusion--from a
biocompatible metallic or polymer material, or a metallic or
polymer material that is suitably coated, impregnated, or otherwise
treated with a material to impart biocompatibility, or a
combination of such materials. The material is also desirably
radio-opaque to facilitate fluoroscopic visualization.
[0106] As shown in FIG. 14, the implant 26 includes a pair of
struts 28 and 30 joined by an intermediate rail 32. The rail 32
(like the struts 28 and 30) can take various shapes and have
various cross-sectional geometries. The rail 32 (and/or the struts
28 and 30) can have, e.g., a generally curvilinear (i.e., round or
oval) cross-section, or a generally rectilinear cross section
(i.e., square or rectangular), or combinations thereof.
[0107] The struts 28 and 30 at one or both ends of the rail 32 may
include a fixation element 34 to enhance fixation in tissue.
Various tissue fixation elements 34 can be used, e.g., tissue
penetrating barbs (as shown), pads with roughened surfaces or
tissue in-growth promoting materials, such as polyester fabric. Any
fixation element 34 may, if desired, be combined with suture, an
adhesive, or like material to further secure the implant.
[0108] As shown in FIGS. 15 and 16 show, the fixation element 34 on
the posterior strut 30 is sized and configured to engage tissue at
either an infra-annular position (i.e., engaging the fibrous body
of the annulus) or a supra-annular position (i.e., engaging atrial
tissue) above or near the posterior annulus within the left
atrium.
[0109] The fixation element 34 on anterior strut 28 is sized and
configured to pass through the septum and project into the right
atrium. There, the fixation element 34 itself can engage tissue in
the septum. Alternatively, as FIGS. 15 and 16 show, the fixation
element 34 can include an anchor button 36. The anchor button 36
captures the anterior strut 28 and holds the anterior strut 28
against the septum in the right atrium.
[0110] 2. Implantation
[0111] The implant 26 can be deployed within a catheter 52 from the
right atrium into the left atrium, in the same manner shown in
FIGS. 10A, 10B, and 10C. The fixation element 34 on the posterior
strut 30 is positioned in engagement with tissue in either an
infra-annular or supra-annular location the posterior annulus (as
FIG. 17A shows), and the anterior strut 28 is lead through the
septum (as FIG. 17B shows).
[0112] As FIG. 17B shows, pulling on the anterior strut 28 within
the right atrium (i.e., through the septum) exerts a pulling force
on tissue at or near the posterior annulus (shown by an arrow in
FIG. 17B). The pulling force draws the posterior annulus inwardly
toward the anterior annulus, thereby shortening the annulus along
its minor axis. As previously described, the pulling forces can
also reactively reshape the annulus along its major axis, as well
as reshape surrounding anatomic structures. In this way, the
implant reshapes the valve annulus toward a shape more conducive to
leaflet coaptation, just as the implant 10 previously
described.
[0113] As shown in the embodiment illustrated in FIGS. 15 and 16,
at least two of the implants 26 are desirably used concurrently, to
distribute pulling forces along medial and lateral sides of the
minor axis. In this arrangement, the fixation elements 34 on the
posterior struts 30 take purchase in tissue within the left atrium
in spaced-apart locations above or near or in the posterior
annulus. The fixation elements 34 on the anterior struts 28 jointly
pass through the septum. Pulling on the anterior struts 28 from
within the right atrium draws the posterior annulus toward the
anterior annulus, thereby shortening the annulus across its minor
axis. The anterior struts 28 can be pulled individually or
concurrently to achieve the reshaping desired.
[0114] In this arrangement, as FIG. 16 best shows, one implant 26
is shaped to direct force outward toward the septum wall of the
left atrium, while the other implant 26 is shaped to direct force
outward toward the lateral wall of the left atrium. The resulting
forces are uniformly distributed along the posterior annulus.
[0115] Once the desired degree of pulling force is established, the
anterior struts 28 can be jointly fixed against the septum by the
anchor button 36. As before described, the fixation elements 34
themselves can apply the holding force, without use of the anchor
button 36.
[0116] C. Magnetic Force Systems
[0117] 1. Structure
[0118] FIGS. 18A/B/C and 19A/B show various embodiments of a
magnetic force system 62 that, in use, shortens an axis of a heart
valve using one or more implanted magnetic elements 64. The
implanted magnetic elements 64 generate magnetic field forces that
attract tissue regions of the annulus toward one another.
[0119] As shown in FIGS. 18A/B/C to 19A/B, the tissue regions
comprise the posterior and anterior edges of a mitral valve
annulus. The magnetic field forces draw the tissue regions closer
together across the minor axis of the annulus. The minor axis of
the annulus is thereby shortened. As already described, shortening
of the minor axis can reshape the valve, as well as reshape other
surrounding anatomic structures, to restore the heart valve annulus
and leaflets to a more normal anatomic shape and tension conducive
to coaptation of the leaflets during ventricular systole, which, in
turn, reduces regurgitation.
[0120] In FIGS. 18A and 18B, the magnetic elements 64 comprise two
or more permanent magnets 66. Permanent magnets 66 can comprise,
e.g., alloys of Neodymium-Iron-Boron (NdFeB), alloys of
Aluminum-Nickel-Cobalt (AlNiCo), and Samarium Cobalt (SmCo). A
permanent magnet 66 generates an external magnetic field. As FIGS.
18A and 18B shows, two permanent magnets 66A and 66B are affixed on
or above the annulus in the left atrium, with opposite magnetic
poles facing each other (North-South or South-North). Poles of
opposite polarity attract each other with a magnetic force. The
force of magnetic attraction depends on the strength of the magnets
and the distance between them.
[0121] In FIGS. 18A and 18B, two permanent magnets 66A and 66B of
opposite polarity are affixed, respectively, on or above the
anterior and posterior regions of the annulus, aligned generally
across the minor axis of the annulus. The force of magnetic
attraction (shown by arrows) draws the posterior annulus and the
anterior annulus toward one another, shortening the minor axis (see
FIG. 18C also).
[0122] In FIG. 18B, at least one additional permanent magnet 66C is
provided on or above the posterior annulus on one or both sides of
the magnet aligned on the minor axis. The additional permanent
magnet 66C has a pole facing the adjacent minor axis magnet 66A
that is like the pole of the adjacent minor axis magnet. Poles of
like polarity repel each other with a magnetic force. The force of
magnetic repulsion pushes the additional permanent magnet 66C and
the adjacent minor axis magnet 66A apart, keeping the two magnets
66A and 66C on the posterior annulus apart and stretching tissue
between the magnets 66A and 66C. At the same time, due to the
presence of an additional permanent magnet, the force of magnetic
attraction between the permanent magnets 66A and 66C on the
posterior annulus and the anterior annulus 66B is amplified,
further enhancing the force that draws the posterior annulus and
the anterior annulus toward one another, shortening the minor
axis.
[0123] In FIGS. 19A and 19B, a permanent magnet 66D is affixed on
or above either the anterior annulus or the posterior annulus
generally aligned with the minor axis. In FIGS. 19A and 19B, the
permanent magnet 66D is shown affixed on or above the anterior
annulus. On the opposite annulus (which, in FIGS. 19A and 19B,
comprises the posterior annulus), an array of soft ferromagnetic
materials 68, e.g. Iron (Fe), is affixed.
[0124] Soft magnetic materials 68 are attracted by a permanent
magnet 66D. The force of magnetic attraction draws the posterior
annulus and the anterior annulus toward one another, shortening the
minor axis. The force of attraction can be strengthened (see FIG.
19B) by affixing an additional permanent magnet 66E on or above the
anterior annulus adjacent the minor axis permanent magnet 66D. As
described with respect to the embodiment shown in FIG. 18B, the
additional permanent magnet 66E has a pole facing the adjacent
minor axis magnet that is like the pole of the adjacent minor axis
magnet 66D. The force of magnetic repulsion pushes the additional
permanent magnet and minor axis magnet apart, keeping the two
magnets on the anterior annulus spaced apart and stretching tissue
between the two magnets 66D and 66E.
[0125] As shown in FIG. 20, two or more permanent magnets 66F and
66G having opposite magnetic poles can be affixed on or above given
regions of the annulus (here, the anterior annulus), without
companion, oppositely spaced magnets. The force of magnetic
attraction draws the permanent magnets together, stretching the
tissue along the circumference of the posterior annulus. The
magnetic force field reshaping occasioned in this arrangement
shortens the minor axis, reshaping the annulus.
[0126] As FIGS. 21 and 22 show, the permanent magnets 66 and/or
soft ferromagnetic materials 68 can be machined, laser cut,
chemically etched, or EDM manufactured into packets 70 of various
shapes. The packets 70 are desirably encased or packaged in an
inert, insulation material, such as gold. The packets include one
or more fixation elements 72, which anchor the packets 70 in tissue
on or above the targeted valve annulus.
[0127] In FIGS. 21 and 22, the packets 70 are button-shaped, and
the fixation elements 72 comprise barbs that penetrate tissue.
Other shapes and configuration can, of course, be used.
[0128] In FIGS. 23A/B, the packet 70 is button-shaped and further
includes a leaflet retaining appendage 76. When anchored into
tissue on or above an annulus (see FIG. 24), the leaflet retaining
appendage 76 overlays at least a portion of one or more native
valve leaflets. The leaflet retaining appendage 76 resists leaflet
eversion and/or prolapse. In this way, a system of magnetic
implants not only reshapes the valve annulus along the minor axis,
but also prevents or reduces retrograde flow and regurgitation. The
leaflet retaining appendage 76 does not interfere with the opening
of and blood flow through the leaflets during antegrade flow.
[0129] FIG. 25 shows another embodiment of a magnetic force system
78 that, in use, shortens an axis of a heart valve using one or
more implanted magnets 80 and 82. In FIG. 25, the magnets 80 and 82
are not anchored on or above the annulus within the heart chamber
occupied by the heart valve. Instead, the magnets 80 and 82 are
placed outside the heart chamber to generate magnetic field forces
that attract tissue regions of the annulus toward one another.
[0130] In the embodiment shown in FIG. 25, the heart valve
comprises the mitral valve in the left atrium. A permanent magnet
80 is implanted either in the coronary sinus near the posterior
annulus or on the septum in the right atrium close to the anterior
annulus. In FIG. 25, the permanent magnet 80 is shown implanted in
the coronary sinus. A second magnetic element 82 is implanted in
the other location--here, on the septum in the right atrium close
to the anterior annulus. The second magnetic element 82 can
comprise a permanent magnet having a polarity opposite to the
polarity of the first permanent magnet, or it can comprise a soft
ferromagnetic material. The force of magnetic attraction between
the permanent magnet 80 and the second magnetic element 82 draws
the posterior annulus and the anterior annulus toward one another,
shortening the minor axis.
[0131] Magnetic force systems 62 or 78 that shorten an axis of a
heart valve can be deployed during an open surgical or
thoracoscopic procedure. Alternatively, catheter-based approaches
may also be used.
II. Implant Systems for Directly Lengthening the Major Annulus Axis
while Directly Shortening the Minor Axis
[0132] Any implant of the types just described can be used alone,
to provide direct shortening along the minor axis of the annulus,
which can also provide reactive lengthening of the annulus along
its major axis.
[0133] As FIGS. 26 and 27 show, a given minor axis implant 84 may
also be used in combination with a major axis implant 86, forming a
combined implant system 88. In the system 88, the major axis
implant 86 provides direct lengthening along the major axis of the
annulus. In the system 88, the active lengthening of the major axis
(by the major axis implant 86) is accompanied by the active
shortening of the minor axis (by the minor axis implant 84). Use of
the major axis implant 86 complements the minor axis implant 84,
enhancing the reactive lengthening of the major axis occasioned by
use of the minor axis implant 84.
[0134] Of course, the major axis implant 86 can be used alone. When
used alone, the major axis implant 86 can reactively shorten in the
minor axis, as well as correspondingly reshape other surrounding
anatomic structures.
[0135] The major axis implant 86 can be sized and configured to
achieve other objectives. The major axis implant 86 can, for
example, be sized and configured to shorten the major axis.
Alternatively, the major axis implant 86 can be sized and
configured to merely stabilize tissue adjacent the heart valve
annulus, without attendant lengthening or shortening of the major
axis. As before stated, a major axis implant 86 of these
alternative sizes and configurations can be used alone or in
combination with a minor axis implant.
[0136] A. Elastic Implant Systems
[0137] 1. Single Function Major Axis Implant Structures
[0138] In one representative embodiment (see FIGS. 26 and 27),
e.g., for reshaping a mitral valve annulus, the major axis implant
86 is sized and configured as a single function component to rest
along the major axis of the annulus above and/or along the valve
annulus, alone or in combination with a single function minor axis
implant 84. The major axis implant 86 can be of the type described
in copending U.S. patent application Ser. No. 10/677,104, filed
Oct. 1, 2003, and entitled "Devices, Systems, and Methods for
Reshaping a Heart Valve Annulus," which is incorporated herein by
reference.
[0139] As described in the above-identified application, the major
axis implant 86 is desirably made--e.g., by bending, shaping,
joining, machining, molding, or extrusion--from a biocompatible,
super-elastic metallic material. As shown in FIG. 28, the major
axis implant 86 includes a pair of struts 90 joined by an
intermediate rail 92. As FIGS. 27 and 28 show, the struts 90 of the
major axis implant 86 are sized and configured to rest in, at, or
near the leaflet commissures. The superelastic material of the
implant 86 is selected to possess a desired spring constant, which
imparts to the rail 92 the ability to be elastically compressed
into an elastically loaded condition resting in engagement with
tissue in, at, or near the leaflet commissures. When in its
elastically loaded, compressed condition, the rail 92 exerts
opposing forces to the tissues in, at, or near the commissures
through the struts 90, tending to outwardly displace tissue and
stretch the annulus along its major axis.
[0140] FIGS. 29 and 30 show another representative example of a
single function major axis implant 86. The major axis implant 86
can be used alone (as FIGS. 29 and 30 show) or in association with
a single function minor axis implant 84 to form a system 88 of the
type shown in FIGS. 26 and 27. The implant 86 includes two rails 92
forming a closed rail structure. The rails 92 are supported by legs
134. The legs 134 are generally spaced 180.degree. apart. In use
(see FIG. 30), the implant 86 resides in the atrium above the
mitral valve. The depending base of each leg 134 carries a fixation
element 136. The fixation element 136 takes purchase in atrial
tissue above and near to the commissures along the major axis of
the annulus. The spring force of the legs 134 and rails 92 apply a
spreading force that stretches tissue along the major axis. The
high rails 92 protects against spreading of the leaflets.
[0141] In the illustrated embodiment, the fixation element 136
comprises a pad of barbs that penetrate atrial tissue above the
annulus. However, other types of tissue engaging mechanisms can be
used, e.g., roughened surfaces or tissue in-growth promoting
materials. Placing numerous fixation elements 136 on legs 134 that
engage tissue above the annulus makes it possible to reduce the
force applied per unit of tissue area. Any fixation element 146
may, if desired, be combined with suture, an adhesive, or like
material to further secure the implant.
[0142] Major axis implants 86 like that shown in FIGS. 29 and 30
can be located without the need to identify the exact position of
the commissures. Adjustment of implant position after or during
implantation is also facilitated, as there is no need to remove a
strut from a commissure. Implants 86 like that shown in FIGS. 29
and 30 also present less chance of trauma or damage to tissue and
anatomic structures beneath the annulus.
[0143] 2. Multiple Function Major and Minor Axis Implant
Structures
[0144] In another representative embodiment (see FIG. 31), e.g.,
for reshaping a mitral valve annulus, a multi-function implant 138
can be sized and configured to rest about the annulus (as FIG. 32
shows) and function to reshape both major and minor axes.
[0145] The multi-function implant 138 is desirably made--e.g., by
bending, shaping, joining, machining, molding, or extrusion--from a
biocompatible, super-elastic metallic material. As shown in FIG.
31, the implant 138 includes a pair of struts 140 joined by a pair
of oppositely spaced rails 142 and 144, forming a ring-like
structure. The rails 142 and 144, of course, can take various
shapes.
[0146] As FIG. 32 shows, the struts 140 of the implant 138 are
sized and configured to rest in, at, or near the leaflet
commissures. The superelastic material of the implant 138 is
selected to possess a desired spring constant, which imparts to the
rails 142 and 144 the ability to be elastically compressed into an
elastically loaded condition resting in engagement with tissue in,
at, or near the leaflet commissures. When in the elastically
loaded, compressed condition, the rails 142 and 144 exert opposing
forces to the tissues in, at, or near the commissures through the
struts 140, tending to outwardly displace tissue and providing the
function of stretching the annulus along its major axis.
Alternatively, the struts 140 can comprise the legs and fixation
elements shown in FIGS. 29 and 30, or other forms of tissue
fixation mechanisms, to accommodate purchase in atrial tissue above
the annulus, to perform the same function.
[0147] As FIG. 31 shows, the rails 142 and 144 include fixation
elements 146, which, in the illustrated embodiment, take the form
of tissue penetrating barbs. The fixation elements 146 on the rails
142 and 144 are sized and configured to take purchase in tissue in
either annular, infra-annular or supra-annular tissue adjacent to,
respectively, the anterior annulus and the posterior annulus (as
FIG. 32 shows). The superelastic material of the implant 138 is
selected to possess a desired spring constant, which imparts to the
rails 142 and 144 the ability to be elastically stretched and
placed into tension when resting in engagement with tissue adjacent
the anterior annulus and posterior annulus. When in the elastically
loaded, in-tension condition, the rails 142 and 144 exert opposing
pulling forces on tissue at or near the annulus. This provides the
function of shortening the annulus along its minor axis. The rails
142 and 144 can be expanded apart, e.g., by use of a balloon 148
placed between the rails 142 and 144 and inflated, placing the
fixation elements 146 into contact with tissue. Collapsing the
balloon allows the implant to assume its desired shape with the
tissue attached.
[0148] Other types and forms of tissue fixation elements 146 can be
used. For example, as shown in FIG. 33, the tissue fixation
elements 146 can comprise barbs that are deployed in an inwardly
folded condition. The barbs 146 can be outwardly folded when the
rails 142 and 144 are expanded apart, e.g., by use of a balloon 148
placed between the rails 142 and 144 and inflated (see FIG. 34).
Upon further inflation of the balloon 148 (see FIGS. 35 and 36),
the barbs 146 are driven into in either infra-annular or
supra-annular tissue adjacent to the anterior annulus and the
posterior annulus (as FIG. 37 shows). The balloon 148 also places
the rails 142 and 144 into tension, to perform their intended
function of shortening the minor axis of the annulus.
[0149] In other embodiments, the tissue fixation elements 146 can
take the form of pads with or without tissue penetrating members,
and/or roughened surfaces and/or tissue in-growth promoting
materials, such as polyester fabric. Any fixation element 146 may,
if desired, be combined with suture, an adhesive, or like material
to further secure the implant 138.
[0150] 3. Implantation
[0151] Any of the single function implants 86 or multiple function
implants 138 can be elastically straightened and/or folded to fit
within a catheter or sheath for deployment, as generally shown in
FIG. 10C. Alternatively, the single function implants 86 or
multiple function implants 138 can be deployed during an open
surgical or thoracoscopic procedure.
[0152] For example, with respect to the single function, major axis
implant 86, access into the left atrium through the septum from the
right atrium can be accomplished as shown in FIGS. 10A, 10B, and
10C. The implant delivery catheter 58 carries the major axis
implant 86 in a sheath 60 at its distal end (see FIG. 38A), in a
collapsed, straightened condition. As FIG. 38A shows, under image
guidance, the strut 90 on the leading end of the major axis implant
86 is freed from the sheath 60 and seated retrograde in the medial
commissure of the valve annulus. The sheath 60 is withdrawn in line
with the coaptation line in a lateral direction along the
coaptation line. Progressively freed from the sheath 60, the major
axis implant 86 shapes and seats (as FIGS. 38B and 38C show), until
the trailing strut 90 unfolds and seats within the lateral
commissure. The implant 86 can also be positioned or repositioned
under image guidance within the left atrium using a
catheter-deployed grasping instrument.
[0153] In an alternative embodiment (see FIG. 39), the major axis
implant 86 can include bell-shaped protrusions 94 and 96 formed
along medial and lateral portions of the rail 92. As FIG. 40 shows,
the medial protrusion 94 is sized and configured to extend through
the septum and project into the right atrium. There, the medial
protrusion 94 is exposed for engagement by a grasping instrument
deployed in the right atrium. The grasping instrument in the right
atrium can take hold of the protrusion 94 to facilitate placement
of the rail 92 in compression within the left atrium. Barbed stays
98 can be crimped to the medial protrusion 94 to help maintaining
compression on the rail 92. The medial grasping site, projecting
into the right atrium, also facilitates repositioning and/or
retrieval of the major axis implant 86. The lateral protrusion 96
can likewise be grasped by an instrument in the left atrium for
placing the rail 92 in compression.
[0154] As shown in FIG. 41, both the minor axis implant 84 and the
major axis implant 86 can include grasping protrusions 100 and 102
that jointly project through the septum into the right atrium. Both
protrusions 100 and 102 can be manipulated to place the minor axis
implant 84 into tension and to place the major axis implant 86 into
compression, as previously described, to achieve the desired
reshaping of the annulus.
[0155] B. Elastic Implant-Magnetic Force Field Systems
[0156] Other types of systems that concurrently accomplish direct
major and minor reshaping are possible. For example, FIG. 42 shows
a representative embodiment of a system 104 that includes an
elastic component 106, to provide direct reshaping along one axis
of a valve annulus, and a magnetic force field component 108, to
provide direct reshaping along another axis of the valve
annulus.
[0157] In the embodiment shown in FIG. 42, the valve to be reshaped
is the mitral valve in the left atrium. In this arrangement, the
elastic component 106 comprises an elastic major axis implant of
the type already described (e.g., as shown in FIG. 30 or 39), which
is sized and configured to rest along the major axis of the annulus
above and/or along the valve annulus. As previously described, the
elastic major axis implant 106 stretches the annulus along the
major axis.
[0158] In this arrangement, the magnetic force field component 108
comprises magnetic elements 132 of the type previously described
(e.g., as shown in FIGS. 21A to 21E). The magnetic elements 132 are
located in a spaced-apart relationship across the minor axis on or
above the anterior annulus and the posterior annulus. The magnetic
elements 132 can comprise two permanent magnets of opposite
polarity, or one permanent magnet and one soft ferromagnetic
material. In the illustrated embodiment, the magnetic elements 132
are stabilized at opposite ends of a yoke 110 coupled to the
elastic major axis implant 106 near one of its struts. The magnetic
elements 132 are implanted in tissue on or above the annulus. The
force of magnetic attraction between the magnet components 132
draws the posterior annulus and the anterior annulus toward one
another, shortening the minor axis.
[0159] The yoke 110 supporting the magnetic elements 132 may
possess a spring constant. Placing the yoke 110 into tension at the
time the magnetic elements 132 are implanted on or above the
annulus provides an auxiliary mechanical force, to augment the
magnetic force serving to shorten the minor axis.
III. Annuloplasty Systems
[0160] A. Point Loading
[0161] FIG. 43 shows a point loaded annuloplasty system 112 for
reshaping a heart valve annulus. The system 112 applies a
mechanical force about the perimeter of the heart valve annulus.
The mechanical force pulls on the annulus to restore a generally
oval shape conducive to leaflet coaptation. For purpose of
illustration, FIG. 43 shows the heart valve annulus as comprising
the mitral valve in the left atrium.
[0162] In FIG. 43, the system 112 creates the mechanical force by
circumferentially linking adjacent sites on or above the annulus
with a biocompatible elastic frame 114. In the illustrated
embodiment, the frame 114 comprises an elastic material, such as
Selastic.TM. material. The frame 114 links the sites by threading
through a network of fasteners 116 that are inserted into tissue on
or above the annulus. FIGS. 44A to 44C show representative
embodiments of the fasteners 116, which include clip components 118
to accommodate passage of the frame 114 and barbs 120 that secure
the clip components 118 to tissue. The elastic frame 114 is in
tension within the network of fasteners 116. The tension applied by
the frame 114 pulls tissue in or along the annulus together,
thereby tightening the annulus to restore a non-dilated shape.
[0163] An alternative embodiment of a point loading annuloplasty
system 122 is shown in FIG. 45. In FIG. 45, as in FIG. 43, an
elastic frame 114 is placed into tension through a network of
fasteners 116 that are inserted into tissue on or above the
annulus. In FIG. 43, all of the fasteners 116 were located in or
along the annulus. In FIG. 45, one fastener 116' is located in the
right atrium outside the left atrium. The fastener 116' engages the
septum. In this arrangement, the frame 114 passes through the
septum, pulling laterally on the septum toward the left atrium to
reshape tissue along the anterior annulus.
[0164] B. Commissural Annuloplasty
[0165] FIG. 46 shows an implant 124 for performing commissural
annuloplasty. As FIG. 47 shows, the implant 124 is sized and
configured, in use, to rest along the major axis of a heart valve
annulus above and/or along the valve annulus. In the illustrated
embodiment (see FIG. 47), the implant 124 rests along the major
axis of a mitral valve annulus in the left atrium.
[0166] The implant 124 is desirably made--e.g., by bending,
shaping, joining, machining, molding, or extrusion--from a
biocompatible metallic or plastic material. As shown in FIG. 39,
the implant 124 includes a pair of struts 126 joined by an
intermediate rail 128.
[0167] As FIG. 47 shows, the struts 126 are sized and configured to
rest in either an infra-annular or a supra-annular position at or
near the annulus adjacent the medial and lateral leaflet
commissures.
[0168] The implant 124 includes a jaw 130 that is appended to each
strut 126. The jaws 130 are made from an elastic material. Each jaw
130 is sized and configured to possess a normal, unloaded, shape or
condition (shown in FIG. 46). In this condition, the jaw 130 is not
in compression or tension. The material of each jaw 130 is selected
to possess a desired spring constant. The spring constant imparts
to each jaw 130 the ability to be elastically spread apart (see
FIG. 48A) and placed in tension out of its normal, unloaded
condition, in response to external stretching forces applied to the
jaws 130.
[0169] When the jaws 130 are anchored in tissue in a stretched
apart condition at or near the commissures (see FIGS. 48A and 48B),
the jaws 130 assumes an elastically loaded, in-tension condition.
When in this elastically loaded, in-tension condition, the jaws 130
exert opposing pulling forces on tissues at or near the
commissures. These forces are shown by arrows in FIG. 48B. The
pulling forces inwardly displace tissue at the commissures,
squeezing the annulus together at the commissures to promote
leaflet coaptation.
[0170] The implant 124 can rest as shown in FIG. 47 without being
in compression and/or tension, thereby itself applying no pushing
or pulling force upon tissue along either, the major or minor axes
of the annulus. Alternatively, the implant 124 can be made of an
elastic material. This imparts to the rail 128 the ability to be
compressed into an elastically loaded condition resting in
engagement with tissue in, at, or near the leaflet commissures.
When in this condition, the rail 124 can exert opposing forces to
the tissues in, at, or near the commissures through the struts 126,
tending to outwardly displace tissue and stretch the annulus along
its major axis.
[0171] Furthermore, as shown in FIG. 49, one or both of the jaws
130 of the implant 124 can be lengthened and shaped to follow the
medial and lateral contours of the annulus, terminating in an
oppositely facing relationship on the anterior annulus and
posterior annulus, similar to the yoke 110 shown in FIG. 42. In
this arrangement, the jaws 130 possess a spring constant. Placing
the jaws 130 in tension across the minor axis of the annulus (as
FIG. 49 shows) at the time of implantation provides a mechanical
force that shortens the minor axis, in the manner previously
described. The jaws 130 can be further lengthened and shaped to
form a full ring-like structure.
[0172] As shown in FIG. 50, the implant 124 can be used in
association with a magnetic force field component 132 of the type
previously described (e.g., as shown in FIGS. 21A to 21E). The
magnetic components 132 are located in a spaced-apart relationship
across the minor axis on or above the anterior annulus and the
posterior annulus. The magnetic components 132 can comprise two
permanent magnets of opposite polarity, or one permanent magnet and
one soft ferromagnetic material. In the illustrated embodiment, The
magnetic components 132 are implanted in tissue on or above the
annulus. The force of magnetic attraction between the magnet
components 132 draws the posterior annulus and the anterior annulus
toward one another, shortening the minor axis.
[0173] Based upon the foregoing, it is apparent that implant
systems can be provided that affect direct shortening of the minor
axis, and/or direct lengthening of the major axis, alone or in
combination using various mechanical and/or magnetic means. It is
also apparent that shaping of a heart valve annulus can be
accomplished by mechanical and/or magnetic force applied
circumferentially about the annulus, and/or by reshaping tissue at
the commissures, alone or in combination with mechanical and/or
magnetic forces that reshape the annulus along its major axis
and/or minor axis.
[0174] While the new devices and methods have been more
specifically described in the context of the treatment of a mitral
heart valve, it should be understood that other heart valve types
can be treated in the same or equivalent fashion. By way of
example, and not by limitation, the present systems and methods
could be used to prevent or reduce retrograde flow in any heart
valve annulus, including the tricuspid valve, the pulmonary valve,
or the aortic valve. In addition, other embodiments and uses 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 should be
considered exemplary and merely descriptive of key technical;
features and principles, and are not meant to be limiting. The true
scope and spirit of the invention are defined by the following
claims. As will be easily understood by those of ordinary skill in
the art, variations and modifications of each of the disclosed
embodiments can be easily made within the scope of this invention
as defined by the following claims.
* * * * *