U.S. patent application number 11/265881 was filed with the patent office on 2006-03-09 for apparatus and methods for cardiac restraint.
Invention is credited to Albert K. Chin.
Application Number | 20060052660 11/265881 |
Document ID | / |
Family ID | 39596600 |
Filed Date | 2006-03-09 |
United States Patent
Application |
20060052660 |
Kind Code |
A1 |
Chin; Albert K. |
March 9, 2006 |
Apparatus and methods for cardiac restraint
Abstract
Apparatus and methods for using the apparatus are disclosed for
cardiac restraint. More specifically, the apparatus and methods are
directed to accessing the pericardium, accessing the heart within
the pericardium, and restraining the heart by at least partially
enclosing the heart with the apparatus. An embodiment of a cardiac
restraint apparatus according to the present invention comprises a
jacket, the jacket having a rim which defines an opening for
receiving a heart. The apparatus also comprises a knot pusher that
has a hollow elongate body, as well as a strand that extends around
the rim of the jacket and is tied into a slipknot. The strand is
positioned such that at least one end portion of the strand extends
through the knot pusher such that a distal end of the knot pusher
can be moved into engagement with the slipknot, whereby pulling the
end portion of the strand away from the heart while pushing the
knot pusher against the slipknot and reducing the diameter of the
opening defined by the rim. In addition, the apparatus comprises
one or more guide elements that are attached to the jacket.
Inventors: |
Chin; Albert K.; (Palo Alto,
CA) |
Correspondence
Address: |
FENWICK & WEST LLP
SILICON VALLEY CENTER
801 CALIFORNIA STREET
MOUNTAIN VIEW
CA
94041
US
|
Family ID: |
39596600 |
Appl. No.: |
11/265881 |
Filed: |
November 2, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10338163 |
Jan 6, 2003 |
|
|
|
11265881 |
Nov 2, 2005 |
|
|
|
09779715 |
Feb 8, 2001 |
6569082 |
|
|
10338163 |
Jan 6, 2003 |
|
|
|
09738608 |
Dec 14, 2000 |
|
|
|
09779715 |
Feb 8, 2001 |
|
|
|
09635345 |
Aug 9, 2000 |
|
|
|
09738608 |
Dec 14, 2000 |
|
|
|
60150737 |
Aug 25, 1999 |
|
|
|
60148130 |
Aug 10, 1999 |
|
|
|
Current U.S.
Class: |
600/37 |
Current CPC
Class: |
A61B 18/1482 20130101;
A61F 2/2481 20130101; A61B 2017/306 20130101; A61B 17/3403
20130101; A61B 17/3421 20130101; A61B 2017/00247 20130101; A61B
2017/00243 20130101; A61B 2018/00291 20130101; A61B 17/3468
20130101; A61B 17/3478 20130101; A61B 2017/3488 20130101; A61B
17/06109 20130101; A61B 17/00008 20130101; A61B 17/3417 20130101;
A61F 2002/2484 20130101; A61B 90/11 20160201; A61N 2001/0578
20130101; A61B 2018/00982 20130101; A61B 90/39 20160201; A61B
2017/22077 20130101; A61B 2017/320044 20130101; A61B 2017/3445
20130101; A61B 2090/062 20160201; A61B 1/00154 20130101; A61B
2017/061 20130101; A61B 2018/00392 20130101; A61B 2090/036
20160201; A61N 1/0587 20130101 |
Class at
Publication: |
600/037 |
International
Class: |
A61F 2/00 20060101
A61F002/00 |
Claims
1-7. (canceled)
8. A method for positioning a cardiac restraint apparatus about the
heart, the method comprising the steps of: forming a surgical
incision as an entry port for the cardiac restraint apparatus;
introducing a cutting tool through the incision for forming an
opening in the pericardium to pass the cardiac restraint apparatus
therethrough; advancing the cardiac restraint apparatus through the
incision and the opening into engagement with the heart; and
positioning the cardiac restraint apparatus about at least a
portion of the heart.
9. The method according to claim 8 in which the cardiac restraint
apparatus includes a flexible jacket disposed within a confined
configuration, the method comprising advancing said cardiac
restraint apparatus including the flexible jacket in confined
configuration through the incision and the opening into engagement
with the heart; and positioning includes expanding the flexible
jacket from the confined configuration to an expanded configuration
with at least a portion of the heart disposed within the
jacket.
10. The method according to claim 8, wherein the surgical incision
is a subxiphoid incision.
11. The method according to claim 8, wherein the incision is a
trans-xiphoid incision.
12. The method according to claim 8, wherein the incision is a
thorascopic incision.
13. The method according to claim 9 in which the flexible jacket
includes a rim defining an opening through which to receive a
heart, the method further comprising the steps of: tacking the rim
of the jacket in expanded configuration to posterior pericardium;
and manipulating the rim of the jacket over the anterior aspect of
the heart to enclose at least the portion of the heart within the
jacket.
14. The method according to claim 13 including the step of reducing
the opening defined by the rim to enclose at least the portion the
heart therein.
15. The method according to claim 13, in which the rim includes
elements of sufficient length to extent outwardly through an
incision as an entry port for manipulating the rim remotely about
the heart, the method comprising the steps of: manipulating the
elements from outside the entry port for positioning the rim of the
jacket to enclose at least the portion of the heart within the
jacket.
16. The method according to claim 13 in which the rim of the
cardiac restraint apparatus includes at least one elastic band
having a first end and a second end, the method further comprising
the steps of: advancing the cardiac restraint apparatus through the
incision and the opening to position the elastic band about the
heart; and attaching the first and second ends of the elastic band
to secure the elastic band around the heart.
17. The method according to claim 16 in which securing the elastic
band around the heart comprises the steps of: tacking the elastic
band to posterior pericardium at a point between said first and
second ends; moving the first end to the anterior aspect of the
heart, and tacking the first end to the pericardium overlying the
anterior aspect of the heart; and attaching the first and second
ends together at a location over the anterior aspect of the
heart.
18. The method according to claim 17 in which the first and second
ends of the elastic band are attached using a grasping tool
inserted through the incision and opening.
19. Cardiac restraint apparatus for constraining installation about
the heart of a patient, the apparatus comprising: a flexible jacket
having a rim, defining an opening for receiving a heart therein; at
least one element attached to the rim of sufficient length to
extend outside the body of a patient to facilitate remote
manipulation of the jacket into position about the heart of the
patient from outside the patient's body; and a sheath enclosing the
jacket in confined configuration and including a confining wall
having a path thereon of diminished shear strength to facilitate
tearing of the confining wall along the path for selectively
releasing the jacket from the confining configuration within the
sheath.
20. The apparatus according to claim 19 in which the path includes
a succession of perforations to promote tearing of the confining
wall along the path.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
09/779,715, filed Feb. 8, 2001, by Albert K. Chin, entitled
"Apparatus and Method for Cardiac Restraint" which application is a
continuation in part of pending application Ser. No. 09/635,345,
filed Aug. 9, 2000, by Albert K. Chin, entitled "Apparatus and
Method for Subxiphoid Endoscopic Access", hereby incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to apparatus and methods for
restraining the heart. More particularly, the invention relates to
apparatus and methods for accessing the pericardium and at least
partially enclosing the heart with a cardiac restraint
apparatus.
[0004] 2. Description of the Related Art
[0005] The present invention is generally directed to apparatus and
methods for restraint of the cardiac wall. The invention is
particularly suited for the treatment of cardiac diseases which
result in atrial or ventricular dilation. The invention includes
minimally invasive methods to access the heart and restrain the
cardiac wall, resulting in the prevention or reduction of cardiac
dilation in patients known to have experienced such dilation or who
have a predisposition for such dilation occurring in the future. A
cardiac restraint apparatus according to the present invention is
typically applied to the epicardial surface of the heart, such that
the cardiac restraint apparatus at least partially enclosed the
heart.
[0006] Cardiac dilation occurs with different forms of cardiac
disease, including congestive heart disease, post-myocardial
infarctions, and dilated cardiomyopathy. In certain instances,
congestive heart disease may result from viral infections. In such
cases, the heart may enlarge to such an extent that the adverse
consequences of heart enlargement continue after the viral
infection has passed and the disease continues its progressively
debilitating course. In some cases, such as post-myocardial
infarction, the dilation may be localized to only a portion of the
heart. In other cases, such as hypertrophic cardiomyopathy, there
is typically increased resistance to filling of the left ventricle
with concomitant dilation of the left atria. In dilated
cardiomyopathy, the dilation is typically of the left ventricle
with resultant failure of the heart as a pump. In advanced cases,
dilated cardiomyopathy involves the majority of the heart. Causes
of congestive heart disease are not fully known.
[0007] As the heart enlarges, the heart is performing an increasing
amount of work in order to pump blood during each heart beat. In
time, the heart becomes so enlarged that the heart cannot
adequately supply blood. An afflicted patient is fatigued, unable
to perform even simple exerting tasks and experiences pain and
discomfort. Further, as the heart enlarges, the internal heart
valves cannot adequately close. This impairs the function of the
valves and further reduces the heart's ability to supply blood.
With each type of cardiac dilation, there are associated problems
ranging from arrhythmias which arise due to the stretch of
myocardial cells, to leakage of the cardiac valves due to
enlargement of the valvular annulus.
[0008] Drugs are sometimes employed to assist in treating problems
associated with cardiac dilation. For example, Digoxin increases
the contractility of the cardiac muscle and thereby causes enhanced
emptying of the dilated cardiac chambers. On the other hand, some
drugs, for example, beta-blocking drugs, decrease the contractility
of the heart and thus increase the likelihood of dilation. Other
drugs including angiotensin-converting enzyme inhibitors such as
Enalopril, which help to reduce the tendency of the heart to dilate
under the increased diastolic pressure experienced when the
contractility of the heart muscle decreases. Many of these drugs,
however, have side effects which make them undesirable for
long-term use.
[0009] Apparatus to prevent or reduce dilation and thereby reduce
the consequences of dilation have also been described. Patches made
from low porosity materials, for example Dacron.TM., have been used
to support the cardiac wall. Other apparatus are found in U.S. Pat.
No. 4,957,477 to Lundback dated Sep. 18, 1990; U.S. Pat. No.
5,131,905 to Grooters dated Jul. 21, 1992; U.S. Pat. No. 5,150,706
to Cox et al. dated Sep. 29, 1992; U.S. Pat. No. 5,143,082 to
Kindberg et al dated Sep. 1, 1992; U.S. Pat. No. 5,256,132 to
Snyders dated Oct. 26, 1993; U.S. Pat. No. 5,702,343 to Alferness
dated Dec. 30, 1997; U.S. Pat. No. 6,077,218 to Alferness dated
Jun. 20, 2000; U.S. Pat. No. 6,085,754 to Alferness dated Jul. 11,
2000; and U.S. Pat. No. 6,095,968 to Snyders dated Aug. 1,
2000.
[0010] The '477 patent teaches a double-walled jacket surrounding
the heart. A fluid fills a chamber between the walls of the jacket.
The inner wall is positioned against the heart and is pliable to
move with the heart. Movement of the heart during beating displaces
fluid within the jacket chamber. The '706 patent discloses a
medical apparatus for enclosing an internal body organ, comprising
a filamentary strand with noose and free end portions and a
surgical bag with an opening. The '082 patent discloses a cooling
net for cardiac or transplant surgery, comprising a porous net that
is fitted and secured around the organ. Both of the '905 and '132
patents teach cardiac assist apparatus which pump fluid into
chambers opposing the heart to assist systolic contractions of the
heart. The '343 and '218 patents teach an adjustable jacket to
constrain cardiac expansion during diastole. The '754 patent
discloses a biologically compatible jacket adapted to be secured to
the heart. The '968 patent discloses a viscous cardioplasty jacket
for buttressing the ventricular heart walls.
[0011] None of these apparatus include a sheath to facilitate
endoscopic introduction of the apparatus, or guide elements for
positioning the cardiac restraint apparatus around the heart.
Moreover, none of these apparatus include hollow guide tubes that
permit an instrument to be advanced through their lumens to engage
the mouth of the jacket and secure the mouth of the jacket to the
pericardium. Furthermore, none of these references teach the
introduction of a cardiac restraint apparatus via a single
subxiphoid incision. Accordingly, there is a need for an improved
cardiac restraint apparatus that can be more easily introduced via
a minimally invasive approach, and improved minimally invasive
methods for introducing cardiac restraint apparatus.
SUMMARY OF THE INVENTION
[0012] The invention is a method and apparatus for accessing the
heart within the pericardium and restraining the heart by at least
partially enclosing the heart with a cardiac restraint
apparatus.
[0013] One embodiment of a cardiac restraint apparatus according to
the invention comprises a jacket, the jacket having a rim which
defines an opening for receiving a heart. The apparatus also
comprises a knot pusher that has a hollow elongate body, and a
strand that extends around the rim of the jacket and is tied into a
slipknot. The strand is positioned such that at least one end
portion of the strand extends through the knot pusher such that a
distal end of the knot pusher can be moved into engagement with the
slipknot, whereby pulling the end portion of the strand away from
the heart while pushing the knot pusher against the slipknot and
reducing the diameter of the opening defined by the rim. In
addition, the apparatus comprises one or more guide elements that
are attached to the jacket.
[0014] In another embodiment of a cardiac restraint apparatus
according to the invention, the jacket is folded to reduce the
profile of the apparatus. Optionally, the folded jacket is enclosed
by a sheath. One embodiment of such a sheath includes a generally
cylindrical body having a proximal end and a distal end, and also
includes perforations along the sheath body such that the sheath
can be removed from the apparatus by tearing the sheath body along
the perforations. Optionally, a pull tab is attached to the
proximal end of the sheath body. By pulling the pull tab away from
the jacket, the surgeon can tear the sheath along the perforations
and remove the torn sheath from the patient.
[0015] In one embodiment of a cardiac restraint apparatus according
to the invention, the strand extending around the rim of the jacket
is a suture strand, for example a nylon suture strand.
[0016] In a class of embodiments the guide elements are one or more
guide tubes removably attached to the rim of the jacket. In some of
these embodiments, the guide tubes are hollow. In some of the
embodiments, at least one of the guide tubes defines a lumen
dimensioned to receive a surgical instrument, for example a tacking
instrument. In other embodiments, the guide elements are one or
more handles, for example handles composed of suture strands,
attached to the rim of the jacket.
[0017] In another class of embodiments, the apparatus comprises at
least one elastic band having a first portion terminating at a
first end and a second portion terminating at a second end, with
the first portion and the second portion of the elastic band being
joined together at a location between the first end and the second
end. The apparatus also includes a sheath, which includes a
generally cylindrical body having a proximal end and a distal end.
The sheath body may also define perforations, preferably
longitudinally positioned perforations, such that the sheath can be
removed from the apparatus by tearing the body along the
perforations. The sheath can also include a pull tab that is
attached to the proximal end of the sheath body, for pulling the
sheath away from the apparatus by pulling the pull tab away from
the jacket.
[0018] In some such embodiments, the elastic band includes
calibrated markings for calibrating the tension of the elastic
band. In other embodiments, the first and second ends of the
elastic band are configured to be engaged by a grasping
instrument.
[0019] Another aspect of the invention is a method of enclosing the
heart with any embodiment of the inventive cardiac restraint
apparatus. In one embodiment, the invention is a method of at least
partially enclosing a heart with a cardiac restraint apparatus that
includes a jacket. The method comprises the steps of: a) making a
surgical incision to provide an entry point for the cardiac
restraint apparatus; b) introducing a cutting tool through the
incision and using the cutting tool to make an opening in the
pericardium through which the cardiac restraint apparatus can be
advanced into engagement with the heart; c) advancing the cardiac
restraint apparatus through the incision and the opening into
engagement with the heart; and d) sweeping the jacket along the
heart to at least partially enclose the heart in the jacket. The
surgical incision can be a subxiphoid incision, a trans-xiphoid
incision, a thorascopic incision or another incision.
[0020] An alternative embodiment of the inventive method includes
the steps of: a) making a surgical incision to provide an entry
point for an endoscopic cannula; b) inserting the endoscopic
cannula into the surgical incision, wherein the endoscopic cannula
has at least one access port; c) advancing the endoscopic cannula
to the pericardium under endoscopic visualization; d) introducing a
cutting tool into the access port of the endoscopic cannula; e)
making an opening in the pericardium using the cutting tool,
through which the cardiac restraint apparatus can be advanced into
engagement with the heart; f) advancing the endoscopic cannula into
the pericardium through the opening; g) advancing the cardiac
restraint apparatus into at least one access port of the endoscopic
cannula into engagement with the heart; h) sweeping the jacket
along the heart to at least partially enclose the heart in the
jacket.
[0021] Another embodiment of a method according to the invention
uses the embodiment of the cardiac restraint apparatus that
includes a jacket and one or more guide tubes. In this method, the
step of enclosing the heart with the cardiac restraint apparatus
includes the steps of: a) advancing a tacking instrument into at
least one access port of the endoscopic cannula to access the
pericardium; b) tacking the rim of the jacket to the posterior
pericardium using the tacking instrument; and c) manipulating the
guide tubes of the cardiac restraint instrument to sweep the jacket
over the anterior aspect of the heart thereby at least partially
enclosing the heart with the jacket. The jacket is then tightened
around the heart by reducing the diameter of the opening of the
jacket by pulling the end portion of the strand away from the heart
while pushing the knot pusher against the slipknot.
[0022] Another embodiment of a method according to the invention
uses the embodiment of the cardiac restraint apparatus that
includes a jacket and one or more handles. In this method, the step
of enclosing the heart with the cardiac restraint apparatus
includes the steps of: a) advancing one or more guide strands into
at least one access port of the endoscopic cannula, the one or more
guide strands having a sufficient length to enable the proximal
ends of the one or more guide strands to be grasped outside the
body when the distal ends of the guide strands are positioned near
the heart; b) advancing a tacking instrument into at least one
access port of the endoscopic cannula; c) tacking the one or more
guide strands to the posterior pericardium using the tacking
instrument; d) passing the one or more guide strands through the
one or more handles on the rim; and e) using the guide strands to
manipulate the jacket, thereby at least partially enclosing the
heart with the jacket.
[0023] Another embodiment of a method of restraining the heart with
a cardiac restraint apparatus involves a cardiac restraint
apparatus that includes an elastic band. The method comprises the
steps of: a) making a surgical incision to provide an entry point
for the cardiac restraint apparatus; b) introducing a cutting tool
through the incision and using the cutting tool to make an opening
in the pericardium through which the cardiac restraint apparatus
can be advanced into engagement with the heart; c) advancing the
cardiac restraint apparatus through the incision and the opening
into engagement with the heart; and d) restraining the heart with
the elastic band by securing the elastic band around the heart.
This method includes methods in which the surgical incision is a
subxiphoid incision, a trans-xiphoid incision, and a thorascopic
incision.
[0024] An alternative embodiment of this method includes the steps
of: a) making a surgical incision to provide an entry point for an
endoscopic cannula; b) inserting the endoscopic cannula into the
surgical incision, wherein the endoscopic cannula has at least one
access port; c) advancing the endoscopic cannula to the pericardium
under endoscopic visualization; d) introducing a cutting tool into
the access port of the endoscopic cannula; e) making an opening in
the pericardium using the cutting tool, through which the cardiac
restraint apparatus can be advanced into engagement with the heart;
f) advancing the endoscopic cannula into the pericardium through
the opening; g) advancing the cardiac restraint apparatus into at
least one access port of the endoscopic cannula into engagement
with the heart, and h) restraining the heart with the elastic band
by securing the elastic band around the heart.
[0025] In the methods using the cardiac restraint apparatus that
includes at least one elastic band, in one embodiment the step of
restraining the heart with the cardiac restraint apparatus can
include the steps of: a) advancing a tacking instrument into the
opening in the pericardium (or, in the minimally invasive methods,
into the access port of the endoscopic cannula to access the
pericardium); b) tacking the elastic band to the posterior
pericardium at a point between the first end and the second end; c)
grasping the first portion, moving the first portion to the
anterior aspect of the heart, and tacking the first portion to the
pericardium overlying the anterior aspect of the heart; d) grasping
the second portion, moving the second portion over the anterior
aspect of the heart, and tacking the second portion to the
pericardium overlying the anterior aspect of the heart; and e)
attaching (preferably by tacking or clipping) the first and second
portions together (preferably at a location overlying the anterior
aspect of the heart) to provide a calibrated tension on the heart.
The steps of grasping the first and second portions of the elastic
band may be performed with any of a variety of grasping tools, for
example a clip applier.
BRIEF DESCRIPTION OF THE FIGURES
[0026] FIG. 1 is a perspective view of one embodiment of a cardiac
restraint apparatus of the present invention.
[0027] FIG. 2 is a partial cross sectional view of the operation of
the knot pusher in reducing the diameter of the opening of an
embodiment of a cardiac restraint apparatus according to the
present invention.
[0028] FIG. 3 is a cross sectional view of a portion of the rim of
a jacket of an embodiment of a cardiac restraint apparatus
according to the present invention.
[0029] FIG. 4 is a perspective view of an alternative embodiment of
a cardiac restraint apparatus of the present invention.
[0030] FIG. 5 is a perspective view of a sheathed cardiac restraint
apparatus of the present invention.
[0031] FIGS. 6A through 6G are partial cross sectional views of a
method of accessing the heart with an endoscopic cannula using a
subxiphoid approach.
[0032] FIGS. 7A through 7D are partial cross sectional views of the
operation of an endoscopic cannula and the use of a cardiac
restraint apparatus in accordance with the present invention.
[0033] FIGS. 8A through 8C are partial cross sectional views of an
alternative method of the operation of an endoscopic cannula and
the use of an alternative embodiment of a cardiac restraint
apparatus in accordance with the present invention.
[0034] FIGS. 9A through 9B are perspective views of an alternative
embodiment of a cardiac restraint apparatus according to the
present invention.
[0035] FIGS. 10A through 10C are partial cross sectional views of
the operation of an endoscopic cannula and the use of an
alternative embodiment of a cardiac restraint apparatus according
to the present invention.
DETAILED DESCRIPTION
[0036] As defined in this application, the word "distal" is used to
describe that portion of the apparatus (or that direction of
movement) which extends away from the user during use, and the word
"proximal" is used to describe that portion of the apparatus (or
that direction of movement) that extends toward the user during
use.
[0037] FIG. 1 illustrates a preferred embodiment of a cardiac
restraint apparatus 100 which embodies an aspect of the invention.
Cardiac restraint apparatus 100 comprises jacket 130 and rim 140,
the rim 140 defining opening 150 sufficiently large to receive a
heart. Jacket 130 is attached to rim 140 along substantially the
entire perimeter of the open end of jacket 140. The apparatus
further comprises knot pusher 120 and strand 160 having end 165
which extends through knot pusher 120. The apparatus also includes
guide tubes 110 and 112, removably attached to rim 140. Strand 160
extends around rim 140.
[0038] Jacket 130 can be constructed of a wide variety of
materials, but generally it should be constructed from materials
that are biocompatible and non-toxic to bodily tissue, for example
distensible or non-distensible mesh fabric constructed from silicon
rubber, nylon, polyurethane, polyester, polytetrafluoroethylene
(PTFE), expanded PTFE (ePTFE), polypropylene, stainless steel, and
impregnated elastomers such as nylon in polyurethane or nylon in
silicon rubber. While FIG. 1 illustrates jacket 130 as being open
at one end and closed at the other, the invention also contemplates
a jacket that is open at both ends.
[0039] Rim 140 is preferably hollow, for example constructed as a
hollow tube or a folded fabric sleeve, which is capable of
receiving and containing strand 160. Rim 140 may be constructed
separately from any biocompatible, flexible material (such as
biocompatible fabrics and plastics) and attached to jacket 130
around the perimeter of opening 150, or may alternatively be
constructed by simply folding and securing the mesh fabric of
jacket 140 around opening 150 to create a hollow fabric sleeve.
[0040] Knot pusher 120 can be constructed from any suitable
material capable of being formed into a hollow tube, for example
rigid and flexible plastics, metals such as stainless steel, and
wood.
[0041] Strand 160 can be constructed from any conventional surgical
suture material, for example nylon, silk, steel, catgut, and
conventional bioabsorbable suture materials such as polymers and
copolymers of lactide, glycotide, para-dioxanone and trimethylene
carbonate. At least one end 165 of strand 160 is disposed within
knot pusher 120. As used in the present invention, the term
"strand" is deemed to include any of a variety of strings, fibers,
wires, or sutures capable of being tied into a slipknot.
[0042] FIG. 2 best illustrates the structural relationship between
knot pusher 120, rim 140 and strand 160. In this figure, guide
tubes 110 and 112 have been omitted for clarity. At the juncture
where knot pusher 120 meets rim 140, strand 160 is tied into
slipknot 670. At least one end 165 of strand 160 is disposed within
knot pusher 120, which in this figure is illustrated as being
tapered. Such taper is entirely optional and in no way limits the
invention. The operation of knot pusher 120 is illustrated using
arrows 680 and 690 in FIG. 2. Strand 160 is pulled away from the
heart in the direction of arrow 680 (proximally) while knot pusher
120 is pushed against the slipknot in the direction of arrow 690
(distally). The distal movement of knot pusher 120 pushes knot
pusher 120 against slipknot 670, holding slipknot 670 while pulling
strand 160 away from the heart and causing a reduction of the
diameter of opening 150, thereby tightening jacket 130 around the
heart (not shown).
[0043] Referring again to FIG. 1, the illustrated embodiment of a
cardiac restraint apparatus according to the invention also
includes one or more guide tubes 110 and 112, removably attached to
rim 140. Guide tubes 110 and 112 may be attached by any suitable
detachable means, for example by having perforations at the site of
attachment. A preferable means of removably attaching guide tubes
110 and 112 to rim 140 will be described with reference to FIG. 3.
FIG. 3 is a cross sectional view of a portion of the rim of a
jacket of a cardiac restraint apparatus according to the invention,
more specifically, section AA' of rim 140 as illustrated in FIG. 1.
In this embodiment, rim 140 includes an opening 730 at the site
where guide tube 110 meets rim 140. Connecting strand 710 extends
within guide tube 110, is looped over strand 160 (strand 160
extends within and around rim 140), and is tied into knot 720.
Guide tube 110 is removable by cutting connecting strand 710 or
unraveling knot 720 and disengaging connecting strand 720 from
strand 160, thereby disengaging guide tube 110 from rim 140. Guide
tubes 110 and 112 can be constructed from any suitable material
capable of being formed into a hollow tube, for example rigid and
flexible plastics, metals such as stainless steel, and wood.
Preferably guide tubes 110 and 112 have a diameter of about 1 mm to
1.5 mm.
[0044] An alternative embodiment of a cardiac restraint apparatus
according to the present invention is illustrated in FIG. 4.
Cardiac restraint apparatus 200 is similar to the cardiac restraint
apparatus 100 of FIG. 1, except that rather than including guide
tubes, it includes at least one handle for guiding the apparatus
during performance of a surgical procedure. Thus, the guide tubes
110 and 112 shown in FIG. 1 and the handles 210 and 212 shown in
FIG. 2 are alternative embodiments of guide elements to help in
guiding the placement of the cardiac restraint apparatus around the
heart during surgery. Specifically, this alternative embodiment of
a cardiac restraint apparatus according to the invention comprises
jacket 230 and rim 240, the rim 240 defining opening 250
sufficiently large to receive a heart. Jacket 230 is attached to
rim 240 along substantially the entire perimeter of the open end of
jacket 240. The apparatus further comprises knot pusher 220 and
strand 260 having end 265 which extends through knot pusher 220 and
extends around rim 240. The apparatus also includes handles 210 and
212 attached to rim 240.
[0045] Handles 210 and 212 may be constructed from any conventional
surgical suture material, for example nylon, silk, steel, catgut,
and conventional bioabsorbable suture materials such as polymers
and copolymers of lactide, glycotide, para-dioxanone and
trimethylene carbonate. Handles 210 and 212 may be attached to rim
240 by any suitable means, for example using adhesives, welding, or
tying handles 210 and 212 around rim 240. Optionally, handles 210
and 212 may be removably attached to rim 240, for example by using
a perforated strap (not shown).
[0046] FIG. 5 is a perspective view of a sheathed embodiment of the
cardiac restraint apparatus of the present invention. Sheathed
apparatus 300 is the cardiac restraint apparatus illustrated in
FIG. 1 that has been placed in a compact state and sheathed within
sheath 320. Jacket 130 and rim 140 of apparatus 100 are folded,
creased or crumpled to reduce their profile before being enclosed
by sheath 320. Jacket 130 moves into a non-compact state,
illustrated in FIG. 1, when sheath 320 is removed.
[0047] Sheath 320 can be constructed from any flexible material,
including but not limited to polyethylene, polyvinylchloride, and
teflon. Sheath 320 may be of any structure suitable to enclose
jacket 130. Preferably, sheath 320 includes a generally cylindrical
body 360 having a proximal end 315 and a distal end 318, sheath
body 360 defining perforations 310 along sheath body 360, and pull
tab 350 attached to proximal end 315. Preferably, perforations 310
are longitudinally positioned. Sheath body 360 defines a lumen
having an inner diameter of preferably 7 mm to 10 mm. Sheath 320 is
removable from apparatus 300 by tearing sheath body 360 along
perforations 310. This removal is more easily accomplished by
implanting sheath 320 with a pull tab 350 extending out from the
proximal end 315 of sheath body 360. Pulling of pull tab 350 away
from the apparatus 300 results in tearing of sheath body 360 along
perforations 310 and removal of the torn sheath 320 from jacket
130.
[0048] Another alternative embodiment of a cardiac restraint
apparatus according to the present invention is illustrated in
FIGS. 9A-9B. In this embodiment, cardiac restraint apparatus 960
comprises at least one elastic band 980 having a first portion 990
terminating at a first end 992 and a second portion 995 terminating
at a second end 996, with the first portion 990 and the second
portion 995 of the elastic band 980 being joined together at a
location between first end 992 and second end 996. Thus, elastic
band 980 may be constructed of two separate portions that have been
attached together, or alternatively, it may be one continuous
piece. Elastic band 980 is constructed from any flexible material,
including but hot limited to silicon rubber, nylon, polyurethane,
polyester, polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE),
polypropylene, and impregnated elastomers such as nylon in
polyurethane or nylon in silicon rubber. Preferably, elastic band
980 has a width of about 1 cm, and a thickness of approximately 1-3
mm.
[0049] Each elastic band can be sheathed with a sheath, such as
sheath 962 of FIG. 9B, when introduced into the patient. Sheath 962
has a generally cylindrical body having a proximal end 965 and a
distal end 967, and can be constructed from any flexible material,
including but not limited to polyethylene, polyvinylchloride, and
teflon. Sheath 962 can be of any structure suitable to enclose
elastic band 980 or two or more of elastic bands 980, preferably
enclosing elastic band 980 in a rolled configuration as illustrated
in FIG. 9B. Sheath 962 can define perforations 912, such that the
sheath can be removed by tearing along perforations 912.
Preferably, perforations 912 are longitudinally positioned. The
sheath can also include a pull tab 952 that is attached to the
proximal end 965 of sheath 962, for pulling the sheath away from
the apparatus. Elastic band 980 may also include calibrated
markings 970 for calibrating the tension of the elastic band 980.
In use, a surgeon can calibrate the tension of elastic band 980
using calibrated markings 970 and markinh 971 by stretching elastic
band 980 from its relaxed state and noting the number of calibrated
markings 970 overlapped by marking 971.
[0050] Optionally, the first and second ends of the elastic band
980 are configured to be engaged by a grasping instrument, for
example by including openings 990 and 991 suitably sized to receive
a grasping instrument.
[0051] Another aspect of the present invention is a class of
methods of restraining the heart using any embodiment of the
inventive cardiac restraint apparatus. While any suitable surgical
approach to the heart may be used, for example trans-xiphoid or
thorascopic incisions, the preferred incision is a subxiphoid
incision large enough to allow for insertion of a cannula for
performing minimally invasive surgery, preferably about 2 cm. An
apparatus having a cannula through which the cardiac restraint
apparatus of the present invention can be deployed, and methods of
using the apparatus, are disclosed in detail in co-pending
application Ser. No. 09/635,345, hereby incorporated by reference
in its entirety.
[0052] Briefly, the surgical apparatus preferably used to deploy
the cardiac restraint apparatus through a subxiphoid incision is an
endoscopic cannula comprising a cannula, a transparent tip located
at the distal end of the cannula, and an endoscope preferably
positioned at the distal end of the cannula. The cannula has at
least one lumen, and one or more additional lumens for advancement
of surgical tools. The transparent tip is preferably tapered to
provide better visualization by offsetting and retracting tissue
away from the field of view. Still more preferably, the transparent
tip has a generally conical shape. The transparent tip is
preferably removable and replaceable, such that it may be removed
when it is desired to obtain a sharper image of the surgical
site.
[0053] In a preferred embodiment, the endoscopic cannula may
comprise one or more access ports positioned at a proximal end of
the cannula, for receiving surgical instruments into an instrument
lumen of the cannula. Such a preferred endoscopic cannula further
comprises an endoscopic eyepiece, skewed relative to the proximal
end of the endoscope, for facilitating the viewing of a surgical
site through the endoscope while minimizing interference with
surgical instruments introduced into the cannula.
[0054] Using the methods of this invention, the endoscopic cannula
is either directly advanced to the mediastinum or alternatively, a
cavity is first dilated and the endoscopic cannula is advanced
through the dilated cavity. Once the endoscopic cannula is advanced
into the mediastinum, surgical tools are advanced through the one
or more access ports, and surgical procedures are performed within
the mediastinum. Surgical tools that are used with the endoscopic
cannula in the methods of the present invention include a cutting
tool for creating an opening in the pericardium, as well as the
cardiac restraint apparatus of the present invention.
[0055] In directly advancing the endoscopic cannula, the endoscopic
cannula is inserted directly into the initial subxiphoid incision
and is guided, under endoscopic visualization, to the surgical
site. Alternatively, a cavity toward the surgical site may be first
dilated using a dilation tool according to this invention, and the
cannula may be subsequently advanced within the dilated cavity. The
second method is advantageous because as the dilation tool
generally has a smaller diameter than the endoscopic cannula,
initially inserting the dilation tool minimizes trauma to the heart
and reduces the chance of ventricular fibrillation due to
irritation of the heart with a large diameter instrument.
[0056] The dilation tool optionally used to dilate a cavity for the
endoscopic cannula has an inner cannula having an elongated body, a
transparent tip at the distal end of the elongated body, an
endoscope, and an outer expandable sheath. Preferably, the dilation
tool has a small maximal dimension which minimizes trauma to the
pericardium upon reaching the pericardium. The inner cannula has a
tip having an enlarged region positioned distal to a distal end of
the outer expandable sheath. The inner cannula is withdrawn through
the outer expandable sheath, and the expandable sheath dilates a
cavity concurrent to the retraction of the tip. The expandable
sheath exerts a radial force against the surrounding tissue as the
tip is retracted through the sheath. The radial force provides a
less traumatic dilation than conventional dilation techniques such
as using a bougie dilation, in which shear force is directly
applied to surrounding tissue.
[0057] Once the cavity is dilated, the endoscopic cannula is then
inserted into the incision and advanced into the proximal end of
the expandable sheath. As the endoscopic cannula is advanced to the
pericardium through the sheath, it will also cause the expandable
sheath to expand further and dilate the working tunnel to a
sufficient size to accommodate the endoscopic cannula. The
expandable sheath provides the additional benefit of guiding the
endoscopic cannula to the proper position at the pericardium.
Alternatively, the endoscopic cannula is inserted directly into the
initial incision without dilation.
[0058] In order to restrain the heart with a cardiac restraint
apparatus of the present invention using the subxiphoid method, the
endoscopic cannula is advanced under endoscopic visualization, as
described previously, either directly into the initial subxiphoid
incision or after first dilating a cavity using a dilation tool as
described herein. Upon reaching the pericardium, a flap of the
pericardium is gripped using a pericardial entry instrument as
described herein, and the flap is cut using a cutting tool to
create an opening in the pericardium. In cutting the pericardium,
this invention contemplates cutting the flap of the pericardium
away from the underlying heart.
[0059] The subxiphoid approach method is particularly advantageous
as it enables the surgeon to access all regions of the heart, that
is a 360 degree access capability including the anterior,
posterior, left and right regions of the heart. Using one
embodiment of this method, the cannula is initially inserted into
the pericardium via an incision near the apex of the heart and then
swept over the anterior and posterior surfaces of the heart. It
should be noted that while entry near the apex of the heart aids
the surgeon by providing a landmark for easier recognition of the
position of the endoscopic cannula within the body, such an entry
is not required by this invention and other entry positions, such
as entry in the posterior region of the heart, are also
contemplated. Once inside the pericardium, the cannula can be
maneuvered around the heart substantially because of the subxiphoid
entry and the flexibility of soft tissue around the heart. Thus,
all regions of the heart may be accessed without the need for
invasively lifting or rotating the heart to access posterior or
lateral vessels and structures.
[0060] The subxiphoid access method is advantageous over
conventional methods. As this procedure is performed under
endoscopic visualization it is minimally invasive. In addition, as
the approach is through a subxiphoid incision, there is no need to
go through the pleural cavity and thus no need to deflate the
lungs. Also, although the method requires only a single incision
(that is, the subxiphoid incision), using this method access is
gained to all regions of the heart. Conventionally, such extensive
access to the heart has only been possible using invasive methods
such as pericardial window, open heart surgery, or port access
surgery using several incisions and ports. Thus, using the
subxiphoid access method as herein described, the surgeon may
access all regions of the heart with a single incision, without
needing to go through the pleural cavity.
[0061] The endoscopic cannula with the transparent tapered tip is
used to bluntly dissect a path to the pericardium, through the fat
and connective tissue. Direct visualization allows verification
that the pericardial surface is clean and devoid of adherent fat.
Application of the pericardial entry instrument may occur under
visual guidance on an exposed pericardial surface.
[0062] The subxiphoid method for accessing the heart is illustrated
in more detail in FIGS. 6A-6G. First, a subxiphoid incision is made
overlying an entry point for a surgical procedure. The subxiphoid
incision is preferably small, about 2 cm. The subcutaneous tissue
below the incision is bluntly dissected to expose the linea alba,
which is also incised. Referring now to FIG. 6A, dilation tool 900,
comprising an inner cannula 908 having tapered tip 904 and an outer
expandable sheath 920, is inserted into the subxiphoid incision
910. Tapered tip 904 of inner cannula 908 bluntly dissects a cavity
responsive to the advancement of the dilation tool 900. Dilation
tool 900 is then positioned on the posterior aspect of the xiphoid
process 902. Dilation tool 900 is then advanced within the
mediastinum 960 under endoscopic visualization (tapered tip 904 is
transparent to allow endoscopic visualization). A laparoscopic
endoscope with an attached CCD chip camera (not shown) can be used
to accomplish endoscopic visualization. Since the pericardium 950
is a thin membrane, visualization of the beating heart through the
endoscope underneath a translucent membrane indicates correct
positioning of the dilation tool 900 on the anterior surface of the
pericardium 950.
[0063] In FIG. 6B, Following advancement of the dilation tool 900
to the desired position in the body, expandable sheath 920 is held
in place as inner cannula 908 is retracted through expandable
sheath 920 in the direction indicated by arrow 921. Inner cannula
908 has an enlarged region near its tip (not shown) which causes
expansion of the sheath 920 during retraction of inner cannula 908.
This expansion of sheath 920 dilates the tissue adjacent to the
length of expandable sheath 920 to at least the maximal dimension
of the enlarged region.
[0064] With expandable sheath 920 in place, large diameter
instruments can be sequentially inserted through the proximal end
of expandable sheath 920 without exerting shear force on the tissue
cavity. Expandable sheath 920 accommodates instruments of varying
diameters and cross-sections. Thus, leaving expandable sheath 920
in place maintains a dilated cavity to the desired surgical site,
facilitating the advancement of the next instrument to be used in
the procedure to the correct position within the body.
[0065] FIG. 6C illustrates the step of introducing an endoscopic
cannula 925 with transparent tapered tip 935, used in the methods
of the present invention. Endoscopic cannula 925 is about to be
inserted into expandable sheath 920, which is expanded to
accommodate the larger diameter of the endoscopic cannula 925.
Endoscopic cannula 925 has an elongated body 918 which defines one
or more lumens. One of the lumens may be used as an endoscopic
lumen to house an endoscope, while the other lumen may be used as
an access port 909 for housing surgical apparatus, advanced either
concurrently or sequentially, as will be discussed more
specifically below. In order for the endoscopic cannula to be used
for introducing a cardiac restraint apparatus according to the
present invention, the access port 909 should be approximately
12-15 mm in diameter. FIG. 6D shows endoscopic cannula 925 in
position inside expandable sheath 920, with tapered tip 935
adjacent to pericardium 950.
[0066] Referring now to FIG. 6E, cutting tool 970 (including
grasping jaws 975 and rotatable cutting tube 976) is inserted into
access port 909 of endoscopic cannula 925 to cut an opening in the
pericardium 950 to access the heart. Cutting tool 970 is
manipulated to grasp the pericardium 950 with the grasping jaws
975, followed by rotation and distal translation of the cutting
tube 976, cutting an opening in the pericardium 950 to permit
insertion of endoscopic cannula 925 into the pericardium 950.
[0067] FIGS. 6F and 6G illustrate the maneuverability of endoscopic
cannula 925 once it is inserted into the pericardium through the
opening created by cutting tool 970. Once inside the pericardium,
endoscopic cannula 925 can be swept around the heart 1000 over the
anterior and posterior surfaces of the heart 1000 (e.g. from the
position shown in FIG. 6F to that shown in FIG. 6G). As shown in
FIGS. 6F and 6G, endoscopic cannula 925 is maneuvered around the
heart 1000 in such a way that all regions of the heart may be
accessed. The endoscopic cannula can be maneuvered because of the
subxiphoid entry position and the flexibility of soft tissue around
the heart, the softness of the tissue allowing the endoscopic
cannula to push apart tissue and move around the heart. Thus, all
regions of the heart may be accessed without the need for
invasively lifting or rotating the heart to access posterior or
lateral vessels and structures.
[0068] It should be noted that while the above method of accessing
the pericardium was described with reference to usage of a dilation
tool having an expandable sheath, a dilation tool without an
expandable sheath may also be used. In that embodiment, the inner
cannula of the dilation tool can be used by itself to dilate a
cavity to access the pericardium, and the endoscopic cannula can be
inserted into the dilated cavity.
[0069] Once the heart is accessed, a cardiac restraint apparatus
according to the invention may be introduced and positioned around
the heart. FIGS. 7A through 7D demonstrate a method of placement of
a cardiac restraint apparatus via subxiphoid incision. While a
subxiphoid approach is the preferred method, the methods of this
invention are not limited to the subxiphoid approach and other
incisions, for example trans-xiphoid and thorascopic, may also be
used, with or without the usage of an endoscopic cannula. FIG. 7A
illustrates an endoscopic cannula 925 in position on the posterior
aspect of the heart 1000 via a subxiphoid approach as previously
described, and a sheathed cardiac restraint apparatus 300 according
to the invention being inserted into access port 909. Endoscopic
cannula 925 also has a second access port, into which a tacking
instrument (not shown) is inserted. Alternatively, the tacking
instrument is inserted through the lumens defined by each one of
guide tubes 110 and 112 in turn instead of through a second access
port of endoscopic cannula 925. In this alternative embodiment,
guide tubes 110 and 112 each define a lumen sufficiently wide to
receive the tacking instrument 700. Guide tubes 110 and 112 are
sufficiently long to remain outside of the body while the jacket is
placed around the heart.
[0070] Next, sheath 320 is removed by pulling pull tab 350 away
from the heart, tearing sheath 320 at perforations 310. The removal
of sheath 320 frees jacket 130, causing it to unwind from its
folded state. The tacking instrument 700 is then used to tack or
staple rim 140 to the posterior pericardium near the base of the
heart, using guide tubes 110 and 112 to better guide the placement
of rim 140 and to hold rim 140 in place in the desired position
during tacking. Following placement of tack 702, each guide tube
110 and 112 is detached from rim 140, for example by cutting strand
710 or unraveling knot 720 as illustrated in FIG. 3.
[0071] As shown in FIGS. 7C and 7D, endoscopic cannula 925 is then
pulled up and over the apex of the heart in the direction of arrow
990, pulling jacket 130 onto the anterior surface of the heart to
at least partially enclose the heart with jacket 130. Manipulation
of jacket 130 may be aided by enlarging the pericardial opening
using a cutting tool as previously described. As shown more clearly
in FIG. 2, strand 160 is then pulled away from the heart while knot
pusher 120 is pushed against slipknot 670 on rim 140, to tighten
jacket 130 around the heart as more clearly illustrated in FIG. 2.
Knot pusher 120 is then disengaged from strand 160, and a pair of
endoscopic scissors (not shown) are advanced through the cannula to
transect the excess tail of strand 160 to conclude the
procedure.
[0072] Alternatively, the endoscopic cannula may be advanced to the
posterior pericardial space without deployment of the cardiac
restraint apparatus, as shown in FIGS. 8A-8C. This alternative
method uses an alternative embodiment of a cardiac restraint
apparatus, as shown in FIG. 4 and described above in detail.
Referring now to FIG. 8A, endoscopic cannula 925 has been
positioned within the pericardium as described above. Guide strands
810 and 820 are then introduced into endoscopic cannula 925 via
access port 909. Guide strands 810 and 820 can be constructed from
any conventional surgical suture material, for example nylon, silk,
steel, catgut, and conventional bioabsorbable suture materials such
as polymers and copolymers of lactide, glycotide, para-dioxanone
and trimethylene carbonate.
[0073] Next, tacking instrument 700 is introduced into access port
909 (or alternatively, into a second access port, not shown) as
illustrated in FIG. 8B. Guide strands 810 and 820 are tacked to the
posterior pericardium using tacking instrument 700. Alternatively,
guide strands 810 and 820 can be tied to a tack in the tacking
instrument 700 prior to its introduction through access port 909.
Guide strands 810 and 820 are then looped through the handles 210
and 212 attached to rim 240 of cardiac restraint apparatus 200, as
shown in FIG. 8B. While in this embodiment of the method jacket 230
is in its unsheathed state, jacket 230 may alternatively be
sheathed as previously described. Cardiac restraint apparatus 200
is pushed, guided by guide strands 810 and 820, into position
posterior to the heart. Guide strands 810 and 820 may be tied
extracorporeally, and the knots pushed up to the previously placed
tacks, to secure the posterior portion of jacket 230. At this
point, if the sheathed configuration of jacket 230 is used, the
jacket is unsheathed as previously described, and opening 250 of
the jacket 230 is pulled inferiorly around the apex of the heart,
then advanced anteriorly into position at the base of the heart as
shown in FIG. 8C. The knot pusher at the anterior mouth of the
jacket is cinched down at the base of the heart as shown in more
detail in FIG. 2 and as previously described, to at least partially
enclose the heart. The excess lengths of guide strands 810 and 820
are cut with endoscopic scissors (not shown) to complete the
procedure.
[0074] Another alternative embodiment of the method uses an
alternative embodiment of a cardiac restraint apparatus according
to this invention, described above and illustrated in FIGS. 9A-9B.
One embodiment of this method, illustrated in FIGS. 10A-10C, is
performed using the subxiphoid access method described above.
Referring now to FIG. 10A, endoscopic cannula 925 is introduced
into the pericardium as previously described. Cardiac restraint
apparatus 960, described above with reference to FIGS. 9A-9B, is
then introduced into access port 909 and into pericardium 950 via
an opening made in the pericardium as previously described. The
introduction of cardiac restraint apparatus 960 into the
pericardium may be optionally facilitated using a rod (not shown)
which pushes cardiac restraint apparatus 960 into the pericardium.
Sheath 962 is then removed by pulling pull tab 952 which causes the
tearing of sheath 962 along perforations 912, releasing elastic
band 980 (not shown) housed within sheath 962.
[0075] Next, referring to FIG. 10B, tacking instrument 700 is
introduced into the pericardium through access port 909. Tacking
instrument 700 is then used to tack elastic band 980 (shown in
detail in FIG. 9A) to the posterior pericardium. Preferably,
elastic band 980 is tacked to the pericardium at a point located
between first portion 990 and second portion 995. Alternatively,
elastic band 980 is tacked to the pericardium at any point located
between first end 992 and second end 996, which are not visible in
the figure. Elastic band 980 can also be attached initially to the
tack of the tacking instrument 700, prior to introduction of both
elastic band 980 and tacking instrument 700 together through access
port 909.
[0076] Next, as shown in FIGS. 10B and 10C, first portion 990 and
second portion 995 of elastic band 980 (more clearly shown in FIG.
9A) are moved from the posterior pericardium to the anterior aspect
of the heart, and are tacked to the pericardium overlying the
heart, preferably to the anterior aspect of the heart. First
portion 990 is moved to the anterior aspect of the heart in the
direction of arrow 1030 by advancing a grasping instrument (not
shown), for example a clip applier, into the pericardium via
endoscopic cannula 925, grasping first portion 990 of elastic band
980, first portion 990 of elastic band 980 from the posterior
pericardium to the anterior aspect of the heart in the direction of
arrow 1030. Optionally, elastic band 980 is configured to receive a
grasping instrument, for example by including openings 990 and 991
as shown in FIG. 9A. Second portion 995 is moved in the opposite
direction, around the posterior aspect of the heart and over to the
anterior aspect of the heart. First portion 990 and second portion
995 are then tacked to the pericardium overlying the heart. The
first portion 990 and second portion 995 can be tacked or clipped
together to complete the procedure.
[0077] While this method has been described with reference to a
subxiphoid approach using an endoscopic cannula, the invention also
contemplates methods in which the surgical incision is a subxiphoid
incision, a trans-xiphoid incision, and a thorascopic incision,
with or without the usage of an endoscopic cannula. In addition,
the invention contemplates the use of one or more elastic bands of
varying widths, preferably using three elastic bands each having a
width of 1 cm.
[0078] Although the invention has been described in connection with
specific preferred embodiments, various modifications and
variations of the described methods and compositions of the
invention will be apparent to those skilled in the art without
departing from the scope and spirit of the invention.
* * * * *