U.S. patent application number 10/054068 was filed with the patent office on 2002-08-15 for device and method for restructuring heart chamber geometry.
Invention is credited to Melvin, David Boyd.
Application Number | 20020111533 10/054068 |
Document ID | / |
Family ID | 27389194 |
Filed Date | 2002-08-15 |
United States Patent
Application |
20020111533 |
Kind Code |
A1 |
Melvin, David Boyd |
August 15, 2002 |
Device and method for restructuring heart chamber geometry
Abstract
A geometric reconfiguration assembly for the natural heart
having a collar configured for surrounding the natural heart. The
collar can include a plurality of supports configured for
positioning on the epicardial surface of the heart. Supports can be
joined with connectors that can permit or provide slight
deformation of the assembly. An external shell or skin portion can
be provided around the supports an/or connectors.
Inventors: |
Melvin, David Boyd;
(Loveland, OH) |
Correspondence
Address: |
RATNER & PRESTIA
P O BOX 980
VALLEY FORGE
PA
19482
|
Family ID: |
27389194 |
Appl. No.: |
10/054068 |
Filed: |
January 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10054068 |
Jan 22, 2002 |
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09326416 |
Jun 4, 1999 |
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09326416 |
Jun 4, 1999 |
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09316611 |
May 21, 1999 |
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09316611 |
May 21, 1999 |
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09165887 |
Sep 30, 1998 |
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6221103 |
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09165887 |
Sep 30, 1998 |
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08581914 |
Jan 2, 1996 |
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5957977 |
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Current U.S.
Class: |
600/37 ;
623/3.1 |
Current CPC
Class: |
A61M 60/122 20210101;
A61F 2/2481 20130101; A61M 60/40 20210101; A61M 60/857 20210101;
A61M 60/148 20210101; A61M 60/268 20210101; A61F 2/02 20130101;
B33Y 80/00 20141201 |
Class at
Publication: |
600/37 ;
623/3.1 |
International
Class: |
A61F 002/00; A61M
001/10 |
Claims
I claim:
1 A geometric reconfiguration assembly for a natural heart,
comprising: a collar configured for surrounding the natural heart
and having a plurality of bands in a spaced relationship; and a
connector bar intersecting the plurality of bands and configured
for maintaining the spaced relationship of the bands to each
other
2. The assembly of claim 1, wherein the connector bar comprises an
inner surface having an outwardly convex curved configuration.
3. The assembly of claim 1, wherein each of the plurality of bands
are positioned parallel to each other.
4. The assembly of claim 1, wherein the assembly comprises from
about 2 to about 10 bands.
5. The assembly of claim 1, wherein the bands comprise a high
strength, high modulus polymer.
6. The assembly of claim 1, wherein the bands comprise a metal.
7. The assembly of claim 1, wherein the connector bar is positioned
tangential to the plurality of bands.
8. The assembly of claim 1, wherein at least one of the bands has a
thickness of about 0.2 mm.
9. The assembly of claim 1, wherein each of the bands includes a
thickness, and the connector bar comprises a plurality of grooves
configured to receive the thickness of each of the plurality of
bands.
10. The assembly of claim 9, wherein the connector bar comprises at
least one beveled groove.
11. The assembly of claim 1, wherein the connector bar comprises a
cushioned portion.
12. The assembly of claim 1, comprises a closure device for
enclosing at least one of the bands in the connector bar.
13. The assembly of claim 1, wherein the collar comprises a first
restrictor region configured to be positioned adjacent the
anterolateral surface of the heart and a second restrictor region
configured to be positioned adjacent posteromedial surface of the
heart.
14. The assembly of claim 11, wherein the cushion portion comprises
a polymeric material.
15. The assembly of claim 1, wherein said assembly comprises a pad
provided adjacent the inner surface of the connector bar.
16. The assembly of claim 15, wherein the pad comprises a low
durometer polymer.
17. The assembly of claim 15, wherein the pad comprises a
cushion.
18. The device of claim 17, wherein the cushion comprises a
gel-filled cushion.
19. The assembly of claim 17, wherein the cushion comprises a
fluid-filled cushion.
20. A geometric reconfiguration assembly for a natural heart,
comprising; a collar for surrounding a portion of the natural
heart, said collar having a portion configured for placement on the
basal portion of the natural heart in between the left and right
pulmonary veins, said collar further comprising an attachment
assembly configured for releasably connecting said collar
together.
21. The assembly of claim 20, wherein the collar comprises an inner
surface having a outwardly convex curve configuration.
22. The assembly of claim 20, wherein the attachment system
comprises a pin and receptacle, said pin and receptacle being
releasably detachable.
23. A geometric reconfiguration assembly for a natural heart,
comprising a collar configured for surrounding the natural heart,
said collar having a first restrictor region for placement adjacent
the anterolateral surface of the heart, and a second restrictor
region configured for positioning adjacent the posteromedial
surface of the heart; the first and second restrictor portions each
comprising a plurality of bands in a space relationship and a
connector bar intersecting the plurality of band and configured for
maintaining the space relationship of the bands to each other.
24. The assembly of claim 23, wherein the collar comprises a first
and second connector portion configured for placement adjacent the
basal portion of the heart and a second connector portion
configured for a position adjacent the apical portion of the
epicardium of the heart.
25. A method for reducing wall tension on one of the chambers of
the heart, comprising the steps of providing a geometric
reconfiguration assembly; and surrounding one of the chambers of
the heart with a geometric configuration assembly.
26. The method of claim 25, comprising the step of occluding blood
inflow into the heart prior to placement of the assembly around the
chamber of the heart.
Description
REFERENCE TO COPENDING APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 09/326,416, filed on Jun. 4, 1999 (allowed),
which is a continuation in part of U.S. patent application Ser. No.
09/316,611, filed on May 21, 1999 (abandoned), which is a
continuation in part application of U.S. patent application Ser.
No. 09/165,887, filed on Sep. 30, 1998 (issued as U.S. Pat. No.
6,221,103), which is a continuation in part application of U.S.
patent application Ser. No. 08/581,914, filed on Jan. 2, 1996
(issued as U.S. Pat. No. 5,957,977). Each of these prior
applications are incorporated by reference.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates to devices and methods for
treating cardiomyopathies and/or enlarged hearts and, more
specifically, devices and methods for decreasing a heart chamber's
wall tension.
BACKGROUND OF THE INVENTION
[0003] The natural heart, and specifically, the cardiac muscle
tissue of the natural heart (e.g., myocardium) can fail for various
reasons to a point where the natural heart cannot provide
sufficient circulation of blood for a body so that life can be
maintained. More specifically, the heart and its chambers can
become enlarged for a variety of causes and/or reasons, including
viral disease, idiopathic disease, valvular disease (mitral, aortic
and/or both), ischemic disease, Chagas' disease and so forth. As
the heart and its chambers enlarge, tension of the walls of the
heart's chambers increase and thus, the heart must develop more
wall tensile stress to generate the needed pressure for pumping
blood through the circulatory system. The process of ventricular
dilation is generally the result of chronic volume overload or
specific damage to the myocardium. In a normal heart that is
exposed to long-term increased cardiac output requirements, for
example, that for an athlete, there is an adaptive process of
slight ventricular dilation and muscle myocyte hypertrophy. In this
way, the heart may fully compensate for the increase cardiac output
requirements of the body. With damage to myocardium or chronic
volume overload, however, there are increased requirements put on
the contracting myocardium to such a level that this compensated
state is never achieved and the heart continues to dilate.
[0004] A problem with an untreated dilated ventricle is that there
is a significant increase in wall tension and/or stress, both
during the diastolic filling, and during the systolic contraction.
In a normal heart, the adaption of muscle hypertrophy (e.g.
thickening) in the ventricular dilation maintains a fairly constant
wall tension for systolic constriction. However, in a failing
heart, the ongoing dilation is greater than the hypertrophy, and as
a result, rising wall tension is required for systolic contraction.
This is believed to result in further muscle damage.
[0005] The increase in wall stress is also true for diastolic
filling. Additionally, because of the lack of cardiac output,
ventricular filling pressure tends to rise due to several
physiologic mechanisms. Moreover, in diastole, both the diameter
and wall pressure increase over normal levels, thus contributing to
higher wall stress levels. As a solution for the enlarged natural
heart, attempts have been made in the past to provide a treatment
to maintain circulation. Prior treatments for heart failure
generally fall into three categories, namely surgical treatments;
mechanical support systems; or pharmacological.
[0006] One such approach has been to replace the existing natural
heart in a patient with an artificial heart or a ventricular assist
device. In using artificial hearts and/or assist devices, a
particular problem stems from the fact that the materials used for
the interior lining of the chambers of an artificial heart are in
direct contact with the circulating blood, which can enhance
undesirable clotting of the blood, build up of calcium, or
otherwise inhibit the blood's normal function. Hence,
thromboembolism and hemolysis could occur with greater ease.
Additionally, the lining of an artificial heart or a ventricular
assist device can crack, which inhibits performance, even if the
crack is at a microscopic level. Moreover, these devices must be
powered by a source which can be cumbersome and/or external to the
body. Drawbacks have limited use of these devices to applications
having too brief a time period to provide a real lasting
benefit.
[0007] An alternative procedure is to transplant a heart from
another human or animal into a patient. The transplant procedure
requires removing an existing organ (i.e., the natural heart) for
substitution with another organ (i.e., another natural heart) from
another human, or potentially, from an animal. Before replacing an
existing organ with another, the substitute organ must be "matched"
to the recipient, which can be, at best, difficult and time
consuming to accomplish. Furthermore, even if the transplanted
organ matches the recipient, a risk exists that the recipient's
body will reject the transplanted organ and attack it as a foreign
object. Moreover, the number of potential donor hearts is far less
than the number of patients in need of a transplant. Although use
of animal hearts would lessen the problem with fewer donors than
recipients, there is an enhanced concern with rejection of the
animal heart.
[0008] In an effort to use the existing natural heart of a patient,
other attempts have been made to reduce wall tension of the heart
by removing a portion of the heart wall, such as a portion of the
left ventricle in a partial left ventriculectomy procedure (the
Batista procedure). A wedge-shaped portion of the ventricular
muscle has been removed, which extends from the apex to the base of
the heart. By reducing the chamber's volume, and thus its radius,
the tension of the chamber's wall is reduced as well. There are,
however, several drawbacks with such a procedure. First, a valve
(i.e., the mitral valve) may need to be repaired or replaced
depending on the amount of cardiac muscle tissue to be removed.
Second, the procedure is invasive and traumatic to the patient. As
such, blood loss and bleeding can be substantial during and after
the procedure. Moreover, as can be appreciated by those skilled in
the industry, the procedure is not reversible. Another device
developed for use with an existing heart for sustaining the
circulatory function of a living being and the pumping action of
the natural heart is an external bypass system, such as a
cardiopulmonary (heart-lung) machine. Typically, bypass systems of
this type are complex and large, and, as such, are limited to short
term use in an operating room during surgery, or to maintaining the
circulation of a patient while awaiting receipt of a transplant
heart. The size and complexity effectively prohibit use of bypass
systems as a long term solution, as they are rarely even portable
devices. Furthermore, long term use of these systems can damage the
blood cells and blood borne products, resulting in post surgical
complications such as bleeding, thromboembolism function, and
increased risk of infection.
[0009] Medicines have been used to assist in treating
cardiomyopathies. Some inotropic agents can stimulate cardiac work.
For example, digoxin can increase the contractibility of the heart,
and thereby enhances emptying of the chambers during systolic
pumping. Medicines, such as diuretics or vasodilators attempt to
reduce or decrease the heart's workload. For example, indirect
vasodilators, such as angiotensin-converting enzyme inhibitors
(e.g., enalopril), can help reduce the tendency of the heart to
dilate under the increased diastolic pressure experienced when the
contractibility of the heart muscle decreases. Many of these
medicines have side effects, such as excessive lowering of blood
pressure, which make them undesirable for long term therapy.
[0010] As can be seen, currently available treatments, procedures,
medicines, and devices for treating end-stage cardiomyopathies have
a number of shortcomings that contribute to the complexity of the
procedure or device. The current procedures and therapies can be
extremely invasive, only provide a benefit for a brief period of
time, or have undesirable side effects which can hamper the heart's
effectiveness. There exists a need in the industry for a device and
procedure that can use the existing heart to provide a practical,
long-term therapy to reduce wall tension of the heart, and thus
improve its pumping efficiency.
SUMMARY OF THE PRESENT INVENTION
[0011] It is the object of the present invention to provide a
device and method for treating cardiomyopathies that addresses and
overcomes the above-mentioned problems and shortcomings in the
thoracic medicine art.
[0012] It is another object of the present invention to provide a
device and method for treating cardiomyopathies that minimizes
damage to the coronary circulatory and the endocardium.
[0013] It is still a further another object of the present
invention to provide a device and method for treating
cardiomyopathies that maintains the stroke volume of the heart.
Another object of the present invention is to provide a device and
method for treating cardiomyopathies that support and maintain the
competence of the heart valves so that the heart valves can
function as intended.
[0014] Still another object of the present invention is to provide
a device and method that increase the pumping effectiveness of the
heart.
[0015] Yet another object of the present invention is to provide a
device and method for treating cardiomyopathies on a long term
basis.
[0016] It is yet still an object of the present invention to
provide a device and method for treating cardiomyopathies that does
not require removal of any portion of an existing natural
heart.
[0017] Still a further object of the present invention is to
provide a device and method for treating dilated cardiomyopathies
that directly reduce the effective radius of a chamber of a heart
in systole as well as in diastole.
[0018] Additional objects, advantages, and other features of the
present invention will be set forth and will become apparent to
those skilled in the art upon examination of the following, or may
be learned with practice of the invention.
[0019] To achieve the foregoing, a geometric reconfiguration
assembly is provided for the natural heart having a collar
configured for surrounding the natural heart. The collar can
include a plurality of bands, such as thin bands of about . 2 mm in
thickness, in a spaced relationship to each other, and a connector
bar intersecting the plurality of bands and configured for
maintaining the spaced relationship of the bands to each other. The
collar may include a plurality of bands, such as from about 2 to
about 10 bands, that are positioned parallel to each other. The
bands can each be made of a biomedical material, such as polyacetal
or a metal, such as titanium or steel.
[0020] The connector bar of the present invention can be positioned
tangential to the plurality of bands, and may have a plurality of
grooves configured to receive the thickness of each of the
plurality of bands. The grooves also may be beveled to allow for
the bands to flex as the heart beats. The connector bar's inner
surface can have an outwardly convex curved configuration, and may
even include a cushioned portion that can be made from a polymeric
material. A pad may be positioned between the collar and the
epicardial surface of the heart that may comprise a low durometer
polymer, or either a gel-filled cushion or a fluid-filled
cushion.
[0021] The assembly of the present invention may also comprise a
closure device for enclosing at least one of the bands in the
connector bar.
[0022] In use, the present invention can reduce the wall tension on
one of the chambers of the heart. A yoke or collar surrounds the
heart so as to provide the chamber of the heart as at least two
contiguous communicating regions, such as sections of truncated
ellipsoids, which have a lesser minimum radii than the chamber
before restructuring. As such, the collar displaces at least two
portions of the chamber wall inwardly from the unrestricted
position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] While the specification concludes with claims particularly
pointing out and distinctly claiming the present invention, it is
believed the same will be better understood from the following
description taken in conjunction with the accompanied drawings in
which:
[0024] FIG. 1 partial frontal anterior view of an exemplar natural
heart;
[0025] FIG. 2 vertical cross sectional view of an exemplar natural
heart and blood vessels leading to and from the natural heart;
[0026] FIG. 3 is a horizontal cross sectional view of an
unrestrained left ventricle of the natural heart;
[0027] FIG. 4 is a horizontal cross sectional view of a heart
restrained made in accordance with the present invention;
[0028] FIG. 5 is a perspective view of a device made in accordance
with the present invention;
[0029] FIG. 6 is an enlarged exploded perspective view of a portion
of the assembly made in accordance with the present invention;
[0030] FIG. 7 is an enlarged perspective view of another portion of
the assembly made in accordance with the present invention;
[0031] FIG. 8 is a cross sectional view of a connector of the
present invention taken along line 8-8 in FIG. 7;
[0032] FIG. 9A is a partial horizontal cross sectional view of an
assembly made in accordance with the present invention while the
heart is at rest;
[0033] FIG. 9B is a partial horizontal cross sectional view of an
assembly made in accordance with the present invention while the
heart is contracting:
[0034] FIG. 10 is a perspective view of the assembly made in
accordance with the present invention and positioned on the left
ventricle;
[0035] FIG. 11 is an alternative embodiment of the assembly made in
accordance with the present invention;
[0036] FIG. 12 is a cross sectional view of one embodiment of the
collar of the present invention taken along line 12-12 in FIG.
11;
[0037] FIG. 13 is a perspective view of another alternative
embodiment of the assembly made in accordance with the present
invention;
[0038] FIG. 14 is a perspective view of yet another alternative
embodiment of the assembly made in accordance with the
invention;
[0039] FIG. 15 is another alternative embodiment of the assembly
made in accordance with the present invention;
[0040] FIG. 16A is a perspective view of the assembly made in
accordance with the present invention;
[0041] FIG. 16B is a perspective view of an alternative embodiment
of the assembly made in accordance with the present invention;
[0042] FIG. 17 is a perspective view of the assembly made in
accordance with the present invention;
[0043] FIG. 18 is a perspective view of the assembly made in
accordance with the present invention;
[0044] FIG. 19 is a perspective view of the assembly of FIG. 18,
with the connector cord and/or portion of the collar secured to the
assembly;
[0045] FIG. 20 is a vertical cross sectional view of one embodiment
of an auxiliary fastener made in accordance with the present
invention;
[0046] FIG. 21 is another vertical cross sectional view of the
auxiliary fastener of FIG. 20 inserted into the assembly;
[0047] s FIG. 22 is another cross sectional view of the auxiliary
fastener of FIG. 20 a period of time after being inserted into
position;
[0048] FIG. 23 is a vertical cross sectional view of the auxiliary
fastener of FIG. 20 after its spike has been absorbed by
tissue;
[0049] FIG. 24 is a perspective view of an exemplar heart with the
assembly of the present invention being positioned on the
heart;
[0050] FIG. 25A is a perspective view of another embodiment of the
present invention;
[0051] FIG. 25B is a top view of an exemplar heart with the
assembly of FIG. 25A of the present invention having been
positioned on the heart;
[0052] FIG. 26 is a perspective view of an exemplar heart with the
assembly of the present invention having been positioned on the
heart;
[0053] FIG. 27A is an enlarged perspective view of a connector
portion of the assembly made in accordance with the present
invention;
[0054] FIG. 27B is a perspective view of the assembly made in
accordance with the present invention including a connector
portion;
[0055] FIG. 27C is a perspective view of the embodiment of FIG.
27B, wherein the ends of the connector portion have been attached
to one another; and
[0056] FIG. 27D is another perspective view of the assembly made in
accordance with the present invention in a generally elongated
configuration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0057] Referring now to the figures in detail wherein like numerals
indicate the same elements throughout the views, an exemplary
natural heart, generally indicated in FIGS. 1 and 2 as 10, has a
lower portion comprising two chambers, namely a left ventricle 12
and a right ventricle 14, which function primarily to supply the
main force that propels blood through the circulatory system,
namely the pulmonary circulatory system, which propels blood to and
from the lungs, and the peripheral circulatory system, which
propels blood through the remainder of the body. A natural heart 10
also includes an upper portion having two chambers, a left atrium
16 and a right atrium 18, which primarily serve as an entryway to
the left and right ventricles 12 and 14, respectively, and assist
in moving blood into the left 10 and right ventricles 12 or 14. The
interventricular wall 40 of cardiac tissue 32 separates the left
and right ventricles 12 and 14, and the atrioventricular wall 42 of
cardiac tissue 32 separates the lower ventricular region from the
upper atrium region.
[0058] Generally, the left and right ventricles 12 and 14,
respectively, each has a cavity 13 and 15, respectively, that is in
fluid communication with cavities 17 and 19, respectively, of the
atria (e.g., 16 and 18) through an atrioventricular valve 50 (which
are each illustrated as being in the closed position in FIG. 2).
More specifically, the left ventricle cavity 13 is in fluid
communication with the left atrium cavity 17 through the mitral
valve 52, while the right ventricle cavity 15 is in fluid
communication with the right atrium cavity 19 through the tricuspid
valve 54.
[0059] Generally, the cavities of the ventricles (e.g., 13 and 15)
are each in fluid communication with the circulatory system (i.e.,
the pulmonary and peripheral circulatory systems) through a
semilunar valve 44 (which are each illustrated as being in the open
position in FIG. 2). More specifically, the left ventricle cavity
13 is in fluid communication with the aorta 26 of the peripheral
circulatory system through the aortic valve 46, while the right
ventricle cavity 15 is in fluid communication with the pulmonary
artery 28 of the pulmonary circulatory system through the pulmonic
valve 48.
[0060] Blood is returned to the heart 10 through the atria (e.g.,
16 and 18). More specifically, the superior vena cava 22 and
inferior vena cava 24 are in fluid communication with and deliver
blood, as it returns from the peripheral circulatory system, to the
right atrium 18 and its cavity 19. The pulmonary veins 30 are in
fluid communication with and delivers blood, as it returns from the
pulmonary circulatory system, to the left atrium 16, and its cavity
17.
[0061] The heart 10 is enclosed in the thoracic cavity within a
double walled sac commonly referred to as the pericardium. Its
inner layer is the visceral pericardium or epicardium, and its
outer layer is the parietal pericardium. The heart 10 is generally
made up of, among other materials, cardiac muscle or tissue 32,
which has an exterior surface commonly known as the epicardial
surface 34 and an interior surface, or endocardial surface 38, that
generally defines the cavities (e.g., ventricular cavities 13 and
15, respectively, and atrial cavities 17 and 19, respectively).
Coronary arteries 36 on the epicardial surface 34 of the heart 10
provide blood and nourishment (e.g., oxygen) to the heart 10 and
its cardiac tissue 32.
[0062] By way of a non-limiting example, the present invention will
be discussed in terms of embodiments that are used to primarily
assist in the restructuring or reconfiguring, and/or operation of
the left ventricle chamber (e.g., 12) of the natural heart 10.
However, it is noted that the present invention can also be used to
assist in the restructuring or reconfiguring, and/or operation of
other portions of the natural heart 10, such as either atria (16
and/or 18), and/or the right ventricle chamber (e.g., 14).
[0063] Turning now to FIG. 3, the chambers of the heart 10,
including the left ventricle chamber 12, is generally shaped as a
hollow truncated ellipsoid having, at any circular cross-section
perpendicular to its long axis, a center point "C.sub.1" and a
radius "R.sub.1" extending from center point C.sub.1 to the
endocardial surface 38. The cardiac tissue 32 of the heart 10 has a
thickness "w," which is generally the distance between the
epicardial surface 34 and the endocardial surface 38.
[0064] An assembly 60 of the present invention preferably is
configured and positioned relative to the natural heart 10 to
displace at least two portions of the cardiac tissue 32 inwardly
(see, e.g., FIG. 4) from the unrestricted position, as exemplified
in FIG. 3. By displacing portions of the cardiac tissue 32
inwardly, the shape of the chamber (e.g., the left ventricle
chamber 12) of the heart 10 is generally restructured or
reconfigured from a generally hollow truncated ellipsoid (see,
e.g., FIG. 3) to a chamber generally shaped as having at least two
continuous communicating portions of truncated ellipsoids (see,
e.g., FIG. 4). In generally reconfiguring or restructuring the
heart 10 as such, each of the truncated ellipsoids has an adjusted
radius "R.sub.2," which is preferably shorter than radius
"R.sub.1."
[0065] Assembly 60 can be static or passive in that it does not
actuate or pump the heart 10, but rather, displaces and holds
portions of the cardiac tissue 32 in a generally predetermined
fixed position as the heart 10 continues to contract (e.g., beat)
and pump blood through its chambers and through the body's
circulatory system. Nevertheless, assembly 60 can be configured and
constructed to permit torsional deformation as the natural heart 10
beats.
[0066] Assembly 60 of the present invention can include a yoke or
collar 62, as exemplified in FIGS. 5-7, to assist in restraining or
restructuring a ventricle, such as the left ventricle chamber 12.
Collar 62 can be any desired shape and preferably surrounds or
encircles the heart 10, and preferably one chamber (e.g., the left
ventricle chamber 12) as exemplified in FIG. 10, so as to
restructure or reconfigure the left ventricle chamber 12 as having
a shape approximating at least two continuous communicating
portions of truncated ellipsoids (see, e.g., FIG. 4). Preferably, a
portion or region 64 of the collar 62 can extend along the
longitudinal plane or along the longer axis of the chamber.
Suitable locations on the epicardial surface 34 for the region 64
can include the basal portion near the atrioventricular groove 43
(see, e.g., FIG. 1) and apical portion 20 of the heart 10, the
anterolateral surface of the left ventricle chamber 12, or the
posteromedial surface of the left ventricle chamber 12.
[0067] The collar 62 may include two or more bands (e.g., 76)
configured for positioning around the heart 10. Preferably, bands
76 are circumferentially flat and may be oriented with the surface
78 being positioned generally tangent to the epicardial surface 34
of the heart 10, and having the smaller dimension, as compared with
surface 80. Surface 80 is generally oriented perpendicular to the
epicardial surface 34. Band 76 should be sized so as to provide for
low deformation in the direction perpendicular to the epicardial
surface 34 of the heart 10, but only require a low strain energy
for tortial deformation as the heart 10 beats. Band 76 can have a
thickness "th" across surface 78 and a width "w" across surface 80,
that each varies depending on the selected material and its
particular deformation characteristics. When metallic material is
used with the present invention, the band 76 can have a thickness
"th" across surface 78 of about 0.2 mm, and can have a width, "w"
across surface 80 from about 5 mm to about 12 mm, and more
preferably, about 7 mm. It should be noted that the particular
dimensions of each assembly 60, and of its components (e.g. collar
62 and its various portions, bands 76, etc.) will depend, as will
be discussed later, according to particular anatomy, the desired
application, and upon the particular size and configuration of the
individual natural heart 10.
[0068] In constructing assembly 60 using bands 76, from about 2 to
about 10 bands 76 may be used, and preferably about 4 bands 76 are
used in the present invention. Nevertheless, the number of bands 76
may be selected depending upon the properties of the material
selected for each of the bands 76, as well as the load stress
required to appropriately restructure the heart chamber
geometry.
[0069] Bands 76 are each preferably made of a light weight,
generally rigid material that has a low bending strain under
expected levels of stress so that the material has sufficient wear
s resistance in use while the heart 10 beats, and maintains its
desired shape in use adjacent the heart 10. Illustrative examples
of suitable materials which may be employed as bands 76 include any
biocompatible or biomedical materials, such as metals, including
titanium or stainless steel, or a suitable polymer, including
polyacetal, polypropylene, rigid polyurethane or an ultra high
molecular weight polyethylene, or a combination of the same.
[0070] The collar 62 may preferably include a connector 82, and
preferably a plurality of connectors 82 spaced along the collar 62,
as exemplified best in FIG. 5. The connectors 82 can assist in
maintaining the space relationship of the bands 76 relative to each
other, and of the assembly 60 to the heart 10. Turning now to FIGS.
6-8, the connector 82 preferably has a contact or an inner surface
84, which is configured for placement adjacent or against the
epicardial surface 34 of the natural heart 10. The inner surface 84
may be configured so that the epicardial surface 34 may slide along
inner surface 84 during contraction and expansion of the heart 10,
and to minimize damage to the epicardial surface 34, and the
coronary arteries (e.g., 36). Preferably, the inner surface 84 is
curved convex outwardly in a longitudinal plane (see, e.g., FIGS. 4
and 8) and has a smooth surface, and/or preferably rounded edges 87
so that collar 62 can be configured to be positioned adjacent or on
the epicardial surface 34 whereby intimate contact can be
established and maintained, even during the contraction or beating
of the heart 10.
[0071] FIGS. 6-8 illustrate the connectors 82 as each including one
or more grooves 92, which can extend inwardly from an opening 98 in
the outer wall 86, and toward the contact or inner surface 84. Each
groove 92 is preferably sized and configured to receive a band 76
whereby its surface 78 would be positioned adjacent the base wall
94, and its surfaces 80 preferably would be positioned adjacent
sidewalls 96.
[0072] In a preferred embodiment, groove 92 should be configured to
assist in allowing flexion movement of the band 76 as the heart 10
beats and moves. As best exemplified in FIGS. 6-8, grooves 92 may
be tapered inwardly as the grooves 92 proceed or extend from the
outer surface 86 inwardly toward the contact surface 84. In
addition, grooves 92 may also be tapered inwardly as the groove
extends from each of the lateral surfaces 88 inwardly (e.g.,
upwardly and/or downwardly), as best illustrated in FIG. 6.
[0073] Connectors 82 are each preferably made of a light weight,
generally rigid material that has a low bending strain under
expected levels of stress so that the material has sufficient wear
resistance in use while the heart 10 beats, and maintains its
desired shape in use adjacent the heart 10. Illustrative examples
of suitable materials which may be employed as connectors 82 may
include any biocompatible or biomedical materials, such as metals,
including titanium or stainless steel, or a suitable polymer,
including polyacetal or an ultra high molecular weight
polyethylene, or a combination of the same.
[0074] Turning back to FIG. 6, a structure 100 can be provided so
as to assist in maintaining the bands 76 in the groove 92, in use.
Any structure 100 contemplated for use with assembly 60 should
assist in restricting movement of the band 76 out of the groove 92
through opening 20 98. In one embodiment, the structure 100 may
take the form of a plate 100 that can be secured or otherwise
attached, and preferably releasably secured, to close off or
restrict access through one or more openings 98. In addition to a
plate-like structure, sutures (not shown) may also be threaded
through the connector 82 to assist in restricting bands 76 movement
through opening 98. Structure 100 is preferably made of a
biocompatible or biomedical material.
[0075] Turning now to FIGS. 11 and 12, an alternative embodiment of
the present invention may include a collar or yoke 162 that
provides an essentially continuous surface which contacts the
epicardium surface 34 of the heart 10. In the present embodiment,
collar 162 may take the form of a generally continuous yoke-like
structure that is essentially rigid and/or elastic. Collar 162
preferably includes a contact or an inner surface 184, which is
configured for placement adjacent or against the epicardial surface
34 of the natural heart 10. The inner surface 184 should be
configured so that the epicardial surface 34 may slide along the
inner surface 184 during contraction and expansion of the natural
heart 10, and to minimize damage to the epicardial surface 34 and
the coronary arteries (e.g., 36). Preferably, the inner surface 184
is curved convexly outwardly in a longitudinal plane and has a
smooth surface, and/or preferably rounded edges 187 so that a
collar 162 can be configured to be positioned adjacent or against
the epicardial surface 34 whereby intimate contact can be
established and maintained, even during the contraction or
expansion of the natural heart 10.
[0076] The collar 162 preferably is selected from a generally rigid
or tough biomedical or biocompatable material. Examples of such
suitable materials which may be employed as collar 162 can include
a metal, such as titanium or steel, or a polymer, such as an ultra
high molecular weight polyethylene, polyurethane, polyacetal, or a
polymer composite material 20 such as carbon fiber-epoxy or
fiberglass-epoxy, or a combination of the same. Moreover, the
collar 162 may be covered, either partially or entirely, with a
material that promotes tissue ingrowth into the collar 162, such as
a soft tissue polyester fabric sheeting or polyletrafluroethyhere
(PTFE).
[0077] In other alternative embodiments, exemplified in FIGS.
13-14, it is contemplated that the collar 162 may include an
attachment system 163 that allows the collar 162 to be placed
around the heart 10, such as between the pulmonary veins 30 (e.g.,
the left and right pulmonary veins 30A and 30B, respectively) near
the basal portion of the heart 10 so as to reduce the possibility
of lateral or medial displacement of the assembly 60, or about the
lateral atrium or the atrioventricular groove region.
[0078] In one embodiment exemplified in FIG. 13, the collar 162 may
include an attachment system 163 that permits the collar 162 to be
separated and then reattached at two or more sites or positions
along the collar 162, preferably adjacent or near the region of the
collar 162 configured for placement adjacent or on the basal
portion and/or apical portion 20 of the natural heart 10. While the
attachment system 163 is illustrated as an interlocking pin 163B
and receptacle 163A (e.g., a ball and socket-like joint), it is
contemplated, and as would be appreciated by those skilled in the
art, that other devices and assemblies for releaseably securing the
collar 162 together can be used. Example of such devices and
assemblies for attachment system 163 could include sutures, a screw
and bore holes through overlapping portions of the collar 162,
clamps, or a combination of these devices and assemblies.
[0079] Alternatively, as exemplified in FIG. 14, the collar 162 may
include an attachment system 163 at one site along the collar 162,
preferably adjacent or at the portion of the collar 162 configured
for placement adjacent or on the basal portion of the heart 10.
This embodiment of collar 162 preferably would include a portion
167 that can either include flexible material, a pivotable section
168, or both to provide movement of the collar 162 so that the
attachment assembly 163 can open, and the collar 162 can be slipped
around the heart 10, such as between the left and right pulmonary
veins 30A and 30B, respectively.
[0080] In yet another embodiment illustrated in FIG. 15, the
assembly 260 may include a collar 262 having a region 264 similar
to the structure of the collar 62, exemplified above in FIGS. 4-8,
and connector portions or regions 268, similar to the structure of
the collar 162, discussed above, and exemplified in FIGS.
11-14.
[0081] Additional embodiments of the present invention are
exemplified in FIGS. 16-19, and may include a collar or yoke 362
that includes an internal frame portion 374 (see, e.g., FIGS. 16A
and 16B) and an external shell or skin portion 400 (see e.g., FIG.
18). The internal frame portion 374 is preferably configured to
support the external shell portion 400, in use, and to assist in
restraining or restructuring a ventricle.
[0082] Turning now to FIGS. 16A and 16B, internal frame portion 374
can include supports 376, 380, and 382, and connectors 390.
Supports 376 are sized and configured to extend generally along a
longitudinal plane of the longer axis of the heart 10, and
preferably, are generally thin elongated panels, with a slight arc
or curvature whereby they are contoured to match the epicardial
surface 34.
[0083] Support 380 is preferably sized and configured to extend
generally around the apical portion 20 of the heart 10, whereas
support 382 is generally U-shaped and is preferably configured to
extend generally around the basal portion of the heart 10. The
supports 376 and 380 are preferably made of a light weight,
generally rigid material that has a low bending strain under
expected stress levels so that the material has sufficient wear
resistance in use while the heart 10 beats, and maintains its
desired shape in use adjacent the heart 10.
[0084] Support 382 is preferably more rigid as it is configured for
being positioned around the basal portion of heart 10, whereby it
can have a greater bending movement applied to it by the heart 10.
Furthermore, it may include a metal brace encased in a polymer.
Moreover, since some embodiments of the invention may be encased in
external shell portion 400, the internal frame portion 374 may be
selected from a group of materials that are not biocompatible, such
as other metallic alloy or other polymer.
[0085] Illustrative examples of suitable materials which may be
employed as supports 376, 380 and 382 can include any biocompatible
or biomedical materials, such as metals, S including titanium,
stainless steel, or a suitable polymer, including polyacetal,
polypropylene, rigid polyurethane, an ultra high molecular weight
polyethylene, a fiber-reinforced polymer composite or a combination
of these materials.
[0086] In the embodiment of FIGS. 16A, support 382 may be
configured to be positioned to the left of the left pulmonary veins
30A (as shown in FIGS. 24 and 26) and/or to the right of the right
pulmonary veins 30B (simply by reversing the orientation of collar
362 from that shown in FIG. 26). Support 382 can be provided in a
generally horn shaped configuration with end portions 384 at each
end of support 382. As illustrated in FIGS. 16B, 25A and 25B,
support 382 can also be configured to be positioned between the
left and right pulmonary veins 30A and 30B, respectively, and in
substantially the same plane as the other supports of collar
362.
[0087] Openings 388 are preferably provided on the surface of the
support number 382, and more preferably in the end portion 384,
whereby a channel 386 extends into, and preferably therethrough.
Openings 388 and channels 386 are preferably sized and configured
to selectively receive a connector cord 396, to assist in
maintaining the position of the assembly on the heart 10, as will
be discussed later herein. A similar horn shaped configuration with
an end portion 384 is provided on the opposite end of support 382
in order to receive the other end of a connector cord 396.
[0088] Supports 376, 380 and/or 382 are preferably connected or
joined to each other with connectors 390, as exemplified in FIGS.
16A and 16B. Connectors 390 are generally provided at or adjacent
the end portions of the supports 376, 380 and/or 382. When attached
to the supports 376, 380 and/or 382, connectors 390 preferably can
provide for low deformation in a direction perpendicular to the
epicardial surface 34 of the heart 10, and can preserve freedom for
slight spontaneous systolic torsion as the heart 10 expands and
contracts. Connector 390 may take the form of a ball and socket
joint 392 that is made from either metal, such as steel, a polymer
such as polyacetal, or a combination of steel and polymer.
[0089] Turning now to FIG. 17, the area around or adjacent
connectors 390 can preferably be provided with a packing 394 to
reinforce the connector 390, and to provide a generally smooth,
generally crevice free surface whereby the external shell portion
400 can easily bind thereto. Moreover, where the external shell
portion 400 is not used with the present invention, the packing 394
can also assist prevent tissue from becoming entangled or embedded
in the connector 390. As such, tissue trauma may be reduced.
Illustrated examples of suitable materials which may be employed as
packing 394 may include silicon rubber or a low durameter polymer
or a gel or an oil. Moreover, packing 394 may be reinforced with
carbon fiber, steel, fiberglass, or another suitable reinforcing
micro fiber composite materials. When packing 394 is employed in
the present invention without external shell portion 400, packing
394 preferably should be selected from a suitable biomedical or
biocompatible material.
[0090] Turning now to FIGS. 16A, 18, and 24, the present invention
can also include one or more connector cords 396 to further assist
in securing the collar 362 to the heart 10, and in maintaining its
position relative to the heart 10. The end of the cord 398 is
preferably joined or attached to a portion of the support 382. As
exemplified in FIGS. 16A, 19, and 24, openings 388 and through
channels 386 may be provided in support 382 and are preferably and
sized and configured to receive at least one end 398 of connector
cord 396. The connector cord 396 may be attached thereto by
suitable devices and techniques, such as by inserting the connector
cord 396 completely through the channel 386, and providing a knot
399 at its end 398, or otherwise securing the connector cord 396 it
so that it does not become detached or disconnected from the
support 382.
[0091] Connector cord 396 should be sized and configured to be
positioned around the base portion of the heart 10. In a preferred
embodiment shown in FIGS. 24 and 26, connector cord 396 should be
sized and configured to pass around the heart 10 through the center
along the oblique sinus between the left and right pulmonary veins
30A and 30B, respectively. Alternatively, connector cord 396 may be
configured to pass around heart 10 to the right of the right
pulmonary veins 30B (see, e.g., FIGS. 25A and 25B), and/or to the
left of the left pulmonary veins 30A (as shown by the dashed lines
in FIGS. 25A and 25B). Also, the connector cord 396 may be sized
and configured to pass through the pericardial reflections behind
either the inferior vena cava 24 or the superior vena cava 22, and
through the free space of the transverse sinus.
[0092] Connector cord 396 is preferably made of any biocompatible
flexible cord or cord-like material. Illustrative examples of
suitable materials which may be employed as connector cord 396
include a braided polyester, a flexible polyurethane, insertion
tape, or a combination of the same.
[0093] An external shell or skin 400 is preferably provided to
encase the internal frame portion 374, and at least a portion
connector cord 396 to provide an essentially continuous surface
which contacts the epicardium surface 34 of the heart 10, in
use.
[0094] Supports 376 having an external shell or skin thereon are
indicated at 364, support 380 having an external shell or skin
thereon is indicated at 368, and support 382 having an external
shell or skin thereon is indicated at 370 on the drawing figures
(see FIG. 18). Also, the portion of connector cord 396 having an
external shell or skin thereon is indicated at 372 in the drawing
figures.
[0095] External shell or skin 400 preferably is a one piece unit
which can include a contact or inner surface 402, which is
generally configured for placement adjacent or against the S
epicardial surface 34.
[0096] The external shell portion 400 can have a thickness of less
than 80 mils, preferably can have as a thickness of up to 20 mils,
and preferably can have a thickness from about 0.5 mils to about 4
mils.
[0097] Furthermore, the inner surface 402 should be configured so
that the epicardial surface 34 may slide along the inner surface
402 during contraction and expansion of the heart 10, and to
minimize damage to the epicardial surface 34 and the coronary
arteries (see, e.g., 36 on FIG. 1). Preferably, the inner surface
402 is formed to be curved or shaped convexly outwardly in a
longitudinal plane, and has a smooth surface and/or preferably
rounded edges so that collar 362 can be configured to be positioned
adjacent or against the epicardial surface 34 of the natural heart
10 whereby intimate contact can be established and maintained
during beating of the natural heart 10. The inner surface 402 also
may be textured to enhance tissue integration into and/or with the
inner surface 402 and the collar 362.
[0098] External shell or skin 400 is preferably selected from a
generally tough or rigid biocompatible or biomedical material.
Illustrative examples of suitable materials which may be employed
as external shell 400 can include a castable polyurethane solution,
such as Tecoflex.RTM. by ThemoCardio Systems of Waltham, Mass. or
Biomer.RTM. by Johnson & Johnson, New Brunswick, N.J.
Alternatively, external shell or skin 400 may be an elastomeric
material selected from a group of various rubbery materials.
[0099] In the manufacture of the collar 362, it is contemplated
that the internal frame portion 374 may be assembled and one end of
connector cord 396 attached thereto. The external shell portion 400
can be provided around or encase the external frame portion 374,
and at least a portion 372 of the connector cord 396 by dipping it
in a solution for the external shell portion 400, or by coating the
external shell portion 400 thereon. Preferably, a stereolithography
technique or other computer-driven fabrication method may be used
to form and harden the external shell portion 400 around the
internal frame portion 374.
[0100] To assist the epicardial surface 34 in separating from any
of the collars 62, 162, or 262 adjacent or at the lateral portions
85 of inner surface 84 without creating substantial negative
pressure, pads can be positioned and/or interposed between the
epicardial surface 34 and the inner surface of the collar. Pad 56
can be, as exemplified in FIGS. 9A and 9B, a fluid-filled or
gel-filled pad or cushion. In the embodiment of FIG. 9A, pads 56
generally will occupy space laterally beyond the collar 62 and the
lateral portions 85 of inner surface 84 of connectors 82 while the
heart 10 is in as a relaxed state. However, as the heart 10
contracts and the wall shortens (see, e.g., FIG. 9B), generally
circumferentially (reducing cavity radius), the epicardial surface
34 will "peel away" from the collar 62 and the lateral portions 85
of inner surface 84 and thus, fluid or gel in the pads 56 can fill
this space so that the inner surface 84 and epicardial surface 34
remain in contact and effect focal restraint whereby the chamber 12
is restructured, as detailed above.
[0101] In one embodiment, the pad 56 is a closed system.
Alternatively, it is contemplated that pad 56 can be configured
such that fluid and/or gel can be added or removed to enhance
functionality of the device assembly of the present invention, as
desired. For example, one or more lines 58 can be in fluid
communication with a chamber in pad 56. Line 58 can extend from pad
56 to an injection port 59, which can be positioned subcutaneous or
elsewhere, as desired, for enhanced access. As will be appreciated
by those skilled in the art, fluid or gel can be injected into the
injection port 59 using a standard syringe and needle, or other
device, to increase the size of the pad 56 and/or the pressure
within the pad 56, as desired.
[0102] Alternatively, fluid or gel can be withdrawn as desired.
[0103] Alternatively, pad 56 can be as a low durometer polymer such
as a plastic or other material (e.g., rubber). In use, as detailed
above, the material accommodates and maintains the contact between
the collar 62, and more specifically its inner surface 84, and
epicardial surface 34 and thus, the desired reconfiguration of the
heart 10 as the heart 10 beats or deforms.
[0104] To assist each of the assembly 60 in remaining fixed in a
spatial or spaced relationship to each other and adjacent or on the
epicardial surface 34, as desired, one or more auxiliary connectors
may be provided (as illustrated in FIGS. 28 and 29). These
auxiliary connectors can take the form of various mechanical
connectors used in the industry to attach and position prosthetic
devices in the body. One type of auxiliary connector is a spike
shaped object or pin 71 that is configured to penetrate the
epicardial surface 34 into the cardiac tissue 32. Also, the
auxiliary connector(s) can take the form of a button 72 and cord
73. One end of the cord 73 can be attached or otherwise secured to
the collar 62, and it can extend inwardly into and through the
cardiac tissue 32. A button 72 can be attached to or adjacent the
other end of the cord 73 adjacent the endocardial surface 38.
Button 72 can be made of any biocompatible material, and is
preferably made of a material that enhances tissue growth around
the button 72 to minimize the possibility of the formation of blood
clots. It is further contemplated that other surgical attachment
articles and techniques can be used in accordance with the present
invention, such as screws, surgical staples and the like, to assist
in fastening and securing the assembly 60 in position, as
desired.
[0105] Furthermore, auxiliary connector(s) can take the form of a
peg 74, as exemplified in FIGS. 20-23, that can configured to be
lockably received in a hole 67 positioned and/or aligned on the
assembly (e.g., assembly 60,) and preferably on the connectors 82
in the case of collar 62. Peg 74 generally comprises a
substantially permanent potion 74A configured preferably to be
snugly received in the hole 67, as discussed above. The portion 74A
can be made of any suitable biomedical or biocompatible material.
Suitable examples of materials for portion 74A, can include the
same materials that can be used with the collar 62, as exemplified
above.
[0106] At the end of the portion 74A of the peg 74, a generally
rigid absorbable spike 74B is provided, which preferably is a
generally frustoconical shaped and tapers inwardly as the spike 74B
extends away from the portion 74A. Spike 74B is sufficiently rigid
so that it can pierce the tissue and then be inserted into the
muscle tissue (e.g., the cardiac tissue 32). The material used for
spike 74B should be a material that is absorbable by the body
tissue over a period of time. Suitable materials can include a
gelatin material, which can be partially denatured thermally or
chemically to control solubility and the absorption rate in the
tissue (e.g., 32), a polyglycol acid, or other materials, as will
be appreciated by those skilled in the industry, used with
absorbable surgical devices or sutures.
[0107] Within the portion 74A and spike 74B is a generally flexible
extension 74C configured, for example, as a strip, coil, tube, or
loop which preferably may include exposed interstices (mesh),
holes, loops or other surface enhancements to promote tissue
ingrowth. Extension 74C can be made from a material to enhance
tissue integration therein. Suitable examples of materials for use
as extension 74C can include polyester, polypropylene, and other
polymers used in as non-dissoluble implants.
[0108] In accordance with the teachings of the present invention,
the assembly of the present invention should be so configured and
positioned adjacent the heart 10 whereby the wall tension is
reduced in accordance with LaPlace's theory of a chamber, which is
as follows:
(Tension of wall)=K*(chamber pressure)*(radius of chamber)(wall
thickness), wherein K is a proportionality constant.
[0109] As an illustrative example of one embodiment in accordance
with the teachings of the present invention, calculations will be
performed based on the following model as exemplified in FIGS. 3
and 5. It is assumed that the long axis of the left ventricle 12 of
the heart 10 is 100 mm, that the equatorial or short axis of the
chamber 12 is 70 mm, that the equatorial wall thickness "w" of the
chamber is about 10 mm and the basal diameter of the heart 10 is 60
mm. An arbitrary slice or plane of the left ventricle 12 will be
analyzed to illustrate local dimensional computations for the
present invention.
[0110] Furthermore, this model will assume that the inner radius
"R.sub.1" (of the slice or plane) of the unrestricted heart 10
(see, e.g., FIG. 3) is about 28.982 mm and that the heart 10 has an
outer radius of about 38.406 mm. As is known to those skilled in
the industry, the width "w" and radius "R.sub.1" can be directly
obtained from high-resolution imaging, such as an echocardiogram,
or preferably, by computation based on an assumed geometric model.
The ratio of the restraint contract pressure of the left ventricle
12 of the device 60 to the cavity pressure can vary from 1 to about
2. This example will further assume that the allowed ratio 20 of
the restraint contact pressure of the left ventricle 12 of device
60 to the cavity pressure is to be limited to a maximum of about
1.5, which is represented by symbol K in the mathematical formulas
below. Also, it is desired to achieve an altered radius "R.sub.2"
of the left ventricle 12 to 80% of its original radius R.sub.1, and
as such:
R.sub.2=0.8*R.sub.1
R.sub.2=0.8*28.982 mm
R.sub.2=23.186 mm
[0111] In order to calculate the radius of curvature "g" of the
inner surface 84 of member 62 in the transverse plane, the
following formula can be used:
g=(w+R.sub.2).div.(k-1)
g=(9.424 mm+23.186 mm).div.(1.5-1)
g=(32.61 mm).div.0.5
g=65.22 mm.
[0112] Now that the value of radius of curvature of the inner
surface 84 "g" has been calculated, the angle ".theta. " between
the line g.sub.1 (joining the center of curvature of the member 62
with one margin, in this plane, of the contact area between inner
surface 84 and the epicardial surface 34) and line g.sub.2 (joining
the same center of curvature with the center of the inner surface
84 in the same plane) can be calculated using the following
formula:
.theta.=(.pi./2)*[R.sub.2-R.sub.1](R.sub.2+W+g)
.theta.=(.pi./2)*[28.982 mm-23.186 mm].div.(28.982 mm+9.424
mm+65.22 mm)
.theta.=(.pi./2)*[5.796 mm].div.(103.636 mm)
.theta.=0.09063 radius or 5.332 degrees
[0113] Using the formula below, the distance inwardly that the
heart 10 should be displaced can be calculated so that the desired
restructuring can be achieved. If "e" is the distance that the
center of either member 62 is to be separated from the absolute
center of a remodeled ventricle in this plane, then:
e=[(g+w+R.sub.2)*cos .theta.]-g
e=[(65.22 mm+9.424 mm+23.186 mm)* cos 5.332 degrees]-65.22 mm
e=32.21 mm.
[0114] As such, twice e or (2*e) is 64.42 mm, and this is the
preferred distance separating the oppositely disposed inner
surfaces 84.
[0115] Based on the calculation, the wall of the heart 10 needs to
be displaced or moved inwardly about 6.20 mm from the unrestrained
position to achieve the desired restructure or reconfiguration
whereby wall tension is adjusted, as desired. Also, using the
formula 2.theta.g to calculate the desired contacting width of the
inner surface 84, which is about 11.68 mm in this example.
[0116] To position the assembly 60 into a body (e.g., the thoracic
cavity) and around an existing natural heart 10, a high resolution
image, such as a standard echocardiogram, or other analysis of the
heart 10 is preferred so that certain anatomical measurements can
be electronically, preferably digitally, recorded and calculated,
as detailed above. While the present application only includes one
set of mathematic calculations to optimize the present invention,
it is contemplated that measurements will need to be taken along
several axes, planes, locations or positions along the longer axis
of the chamber. Pre-surgical calculations are preferred so that the
assembly 60 can be constructed, as desired, before surgery to
minimize surgical time, and preferably reduce or eliminate use of a
heart/lung bypass machine.
[0117] Thoracic surgery may be required to implant assembly 60.
Clinically sufficient anesthesia is administered and standard
cardiac monitoring is applied to the patient and then, via a
sternal or lateral wall incision, the pericardial sac where the
heart 10 is usually situated is opened using standard thoracic
surgical procedures, which are known to those skilled in the
art.
[0118] Once the thoracic cavity and pericardium is opened, the
heart 10 must be narrowed or constricted so that the assembly 60
can be placed around the heart 10. In one embodiment, inflow to the
heart 10 may be occluded. This can be accomplished by placing a
tourniquet around either the superior and/or inferior vena cava 22
and 24, respectively, as illustrated in FIGS. 1 and 2, for a brief
period of time (e.g., about 3 to 4 heartbeats) whereby the heart 10
shrinks and empties. Thereafter, the collar 62 may be slipped
around the heart 10. The tourniquets can be released from occlusion
around the superior and/or inferior vena cavas 22 and 24,
respectively, and the heart 10 re-fills with blood.
[0119] For prolonged reduction of blood pressure by cardiac inflow
occlusion, hypothermia techniques may be employed to lower body
temperature to reduce the side effects that can be caused by
reduced blood pressure in the circulatory system.
[0120] If an open heart procedure is employed in the present
invention, circulation of blood to the natural heart 10 may be
bypassed so the present invention can be inserted on and/or into
the patient. If so, referring back now to FIG. 2, the superior vena
cava 22, the inferior vena cava 24, and aorta 26 are cannulated.
The circulatory system is connected to as a cardiopulmonary bypass
machine so that circulation and oxidation of the blood are
maintained during the surgical procedure. By way of example, the
procedure discussed in detail will be for insertion of the present
invention 60 to restructure or reconfigure the left ventricle
chamber 12.
[0121] Turning now to FIGS. 4-7 and 10, an assembly 60, which may
have been customized according to the anatomical measurements and
calculations, is preferably positioned adjacent or against the
epicardial surface 34 in predetermined locations relative to each
other and relative to the chamber (e.g., left ventricle chamber
12). Assembly 60 is positioned around the heart 10 so that portions
of the heart 10 are displaced or urged inwardly, as desired.
[0122] Turning now to FIGS. 18 and 24-26, collar 362, which also
may have been customized according to the anatomical measurements
and calculations, is preferably positioned adjacent or against the
epicardial surface 34, as discussed above. The connector cord 396
may be extended around the heart 10 either to the left of the left
pulmonary veins 30A (as shown by the dashed lines in FIG. 25B), to
the right of the right pulmonary veins 30B (see, e.g., FIG. 25B),
through the center along the oblique sinus between the left and
right pulmonary veins 30A and 30B, respectively (see, e.g., FIG.
26) or any combination thereof, as desired. The connector cord 396
can be secured to the end portion 384 of support 370. For example,
an end 398 of connector cord 396 may be inserted into opening 388
and through channel 386. The end of 398 may be knotted or otherwise
configured so that the end 398 of connector cord 396 is not
permitted to become removed or detached from the support 370.
[0123] As illustrated in FIGS. 27A-27C, a connector 406 may be
provided on any portion of the collar 362, and preferably on
support 370 whereby selective separation and reattachment of the
first end 408 and second end 410 can be accomplished. The connector
406 can take the form of any suitable releasably locking mechanism
that preferably includes a plurality of various locking positions
to assist in further customizing the present invention to the heart
10, so that the degree of geometric alterations of the present
invention can be adjustable, as desired.
[0124] The apparatus of the present invention can also be placed
around the patient's heart 10 in a minimally invasive procedure,
particularly the apparatus exemplified in FIGS. 13, 14, 25A-B and
27A-C (e.g., assemblies 162 and 362). As shown in FIGS. 27D, collar
362 can be separated at first and second ends 408 and 410, and
folded outwardly into the configuration shown in FIG. 27D (since
connectors 390 will act as hinges). Thereafter, collar 362 may be
inserted into the patient through a port which provides access to
pericardial sac. The port may comprise a simple incision which
extends through the skin into the pericardial sac. Alternatively,
the port can comprise a trocar cannula (or even the operative port
of an endoscope) which has been inserted through the skin into the
pericardial sac. Preferably, the port through which collar 362 is
inserted is located near the apical portion 20 of the heart 10, and
is about 2 cm in length.
[0125] Once assembly 362 has been inserted through the port into
the pericardial sac, it is manipulated into position using one or
more surgical grasping devices in a manner similar to that shown in
FIG. 24. In order to facilitate manipulation and proper placement
of collar 362 about the heart 10, one or more trocars may be
inserted into the patient so as to provide access to the
pericardial sac. Preferably, these trocar(s) are inserted into the
patient at locations which are higher on the chest wall than the
port through which collar 362 is inserted, and an endoscope (more
particularly, a thoracoscope) is inserted through at least one of
the trocar cannulas. The endoscope provides operative vision within
the pericardial sac (such as through a video monitor attached to
the endoscope), and various surgical grasping instruments and other
necessary instruments may be inserted through the operative port of
the endoscope in order to manipulate collar 362 into position
around the heart. Of course these surgical instruments can also be
inserted into any other trocar cannulas positioned to provide
access to the pericardial sac, including the cannula (i.e., the
port) through which collar 362 has been previously inserted.
[0126] Auxiliary connectors can be used to further secure the
assembly 60 to the heart 10. Turning now to FIGS. 20-23, peg 74 can
be inserted in the hole 67, whereby the spike 74B is piercing the
epicardial surface 34 and is being inserted into the tissue (e.g.,
cardiac tissue 32). Peg 74 preferably locks into position once
inserted (see FIG. 21), to further secure the assembly 60 in place.
Over time, it is preferred that spike 74B, which has been inserted
into the tissue, dissolve and be absorbed by the surrounding
tissue. As the spike 74B is being absorbed, extension 74C becomes
exposed to the tissue, and tissue thereby insinuates and grows into
any exposed interstices, loops, holes, or other surface
enhancements to promote tissue ingrowth. The peg 74B can thereafter
be held in place by the tissue insinuation and growth into
extension 74C, which can assist in maintaining the position of
assembly 60.
[0127] Once the assembly 60 is properly positioned and secured,
termination of a cardiopulmonary bypass, if used, is attempted and,
if successful, the thoracotomy is closed.
[0128] Alternatively, once the thoracic cavity and pericardium is
open, the collar 162 exemplified in FIGS. 13 or 14, can be placed
around the heart 10, either between the pulmonary artery 28 and the
superior left atrial surface or between the aorta and the pulmonary
artery 28 and then across the posterior dorsal left atrial surface
in between the left and right pulmonary veins 30A-B, respectively.
A portion of the collar 162, preferably the posterior portion, can
be placed behind the heart 10. An opening is sharply and/or bluntly
developed in the leaves of the pericardium forming the
anterolateral margin of the oblique sinus. Then, a hemostat can be
used to place a portion of the collar 162 through the opening.
[0129] Alternatively, a detachable connector cord (see, e.g., 372
and 396) with one end attached to the portion of the collar 162,
can be grasped and used to pull a portion of the collar 162 through
the opening. Such placement of the collar 162 across the epicardial
surface 34 of the lateral atrium or atrioventricular junction
should reduce the possibility of adverse medial or lateral
displacement or movement of the collar 162.
[0130] An alternative method for positioning the present invention
includes removing the natural heart 10 from the patient,
positioning the components of the present invention on or around
the heart 10, and auto-transplanting the natural heart 10 back into
the patient using standard cardiectomy and cardiac transplant
techniques known in the industry.
[0131] Having shown and described the preferred embodiments to the
present invention, further adaptations of the activation device for
the living heart as described herein can be accomplished by
appropriate modifications by one of ordinary skill in the art
without departing from the scope of the present invention. For
example, the present invention can be used with any one or even as
a plurality of the various chambers of a living heart, and also
could be used with different structural embodiments to restructure
the chamber. Several such potential modifications have been
discussed and others will be apparent to those skilled in the art.
Accordingly, the scope of the present invention should be
considered in terms of the following claims and is understood not
to be limited in the details, structure and operation shown and
described in its specification and drawings.
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