U.S. patent application number 11/407883 was filed with the patent office on 2007-03-29 for pericardium reinforcing devices and methods for using them.
This patent application is currently assigned to The Foundry Inc.. Invention is credited to Bernard H. Andreas, Sunmi K. Chew, Ronald G. French, Hanson S. III Gifford.
Application Number | 20070073100 11/407883 |
Document ID | / |
Family ID | 25507804 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070073100 |
Kind Code |
A1 |
French; Ronald G. ; et
al. |
March 29, 2007 |
Pericardium reinforcing devices and methods for using them
Abstract
A surgical device for reinforcing the pericardial sac
surrounding the heart to assist in the treatment of congestive
heart failure includes an enclosure having an interior and an
exterior. The interior surface limits adhesions or accepts ingrowth
with the myocardial tissue of the epicardium. The exterior surface
is adapted to adhere to or otherwise attach to the pericardium to
provide reinformcement.
Inventors: |
French; Ronald G.; (Santa
Clara, CA) ; Chew; Sunmi K.; (San Jose, CA) ;
Gifford; Hanson S. III; (Woodside, CA) ; Andreas;
Bernard H.; (Redwood City, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
The Foundry Inc.
Menlo Park
CA
|
Family ID: |
25507804 |
Appl. No.: |
11/407883 |
Filed: |
April 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09963848 |
Sep 25, 2001 |
7060023 |
|
|
11407883 |
Apr 19, 2006 |
|
|
|
Current U.S.
Class: |
600/37 ;
623/23.64 |
Current CPC
Class: |
A61F 2/2481
20130101 |
Class at
Publication: |
600/037 ;
623/023.64 |
International
Class: |
A61F 2/04 20060101
A61F002/04 |
Claims
1. A compliant and substantially non-elastic pepcardial
reinforcement comprising a compliant and substantially non-elastic
member having an interior surface for placement adjacent an
epicardium, the interior surface tending to inhibit adhesions with
the epicardium and having an exterior surface for attachment to the
interior of a pericardium.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 09/963,848 (Attorney Docket No. 020979-002400US), filed Sep.
25, 2001, the full disclosure of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] This invention relates to surgical devices and to methods of
using them. In particular, the device is one for reinforcing the
pericardial sac surrounding the heart to assist in the treatment of
congestive heart failure. The device, generically, is an enclosure
having an interior and an exterior. The interior surface is made in
such a way that it tends not to or does not form adhesions with or
accept ingrowth with the myocardial tissue of the epicardium. The
exterior surface of the device, in contrast, is adapted to adhere
to or to ingrow with or otherwise to attach sufficiently to the
pericardium so that it reinforces that membrane or structure. The
nature of the device is that it tends not to allow the pericardium
to expand further with time. The device, after complete deployment,
desirably envelopes some measure of pericardial fluid in its
interior separating it from the epicardial surface. This device
helps to prevent further declination of the condition of the heart
during the course of congestive heart failure. The device is
preferably introduced into the pericardial space and onto the inner
surface of the pericardium using transcutaneous or minimally
invasive techniques.
[0003] Congestive Heart Failure ("CHF"), or simply "Heart Failure"
is a progressive path found in many forms of heart disease. In
general, it is a condition in which the heart is unable to pump
blood at a rate sufficient for the proper supply of nutrients to
metabolizing tissues. There are many specific disease states
leading to CHF, but each typically results in the dilatation of the
ventricles. Various etiologies for CHF are viral and ischemic and,
of course, idiopathic. Myocardial injury and chronic volume
overload generally are thought to cause this course of ventricular
dilatation. The typical adaptation process undertaken by the
stressed heart muscle is not achieved during CHF and, instead of
gaining a stronger heart muscle, the heart instead gets larger as
it attempts to adapt to its increased volume load.
[0004] Chronic pressure overload causes another response mechanism
to develop. Specifically, hypertrophy of the heart muscle,
entailing an increase both in the size of individual muscle cells
and in overall muscle mass, begins to occur. Although this response
helps the heart to overcome higher pressure, it has limitations and
is associated with various structural and biochemical changes that
have deleterious long term effects.
[0005] Additionally, system-wide vascular constriction occurs
during the course of CHF. The constriction causes blood flow to be
redistributed so that certain regions and systems have a reduced
blood supply, e.g., skeletal muscle, kidneys, and skin. These
regions do not produce significant amounts of vasodilating
metabolites. In contrast, the brain and heart have high metabolic
rates and produce a greater amount of vasodilators. Consequently,
the latter organs receives a higher proportion of the restricted
blood supply.
[0006] Therapy for CHF is staged. Correction of a reversible
causative factors is the first line of offense. Treatment of
bradyarrhythmias, perhaps by use of an artificial pacemaker or by
provision of an appropriate drug such as digitalis, can help
alleviate CHF. CHF that continues after correction of such
reversible causes is often treated with a regime of salt
restriction, vasodilators, diuretics, and the like. Bed rest to
increase venous return to the heart and move fluid from the
periphery is often helpful. As noted above, digitalis has been an
important drug for increasing cardiac output in persons with
specific types of CHF. It has been used for over 200 years. Other
drugs used for treatment of CHF include beta-adrenergic agonists
such as norepinephrine, epinephrine, and isoproterenol. Each
stimulate cardiac beta-adrenergic receptors. Dopamine and
dobutamine are also used. Various diuretics and vasodilators for
variously dilating both veins and arteries are used, each for
slightly different reasons based on the detected manifestation of
the CHF in the heart. Few interventional or surgical pathways for
alleviation of CHF are currently widely practiced. Indeed, the only
permanent treatment for CHF is a heart transplant.
[0007] One surgical procedure known as cardiomyoplasty is used for
early stage CHF. In that procedure, a muscle taken from the
shoulder (the latissimus dorsi) is wrapped around the heart. The
added muscle is paced synchronously with the ventricular systole.
This procedure is highly invasive requiring a stemotomy to access
the heart. Some have suggested that the benefits of the procedure
are due more to remodeling from the mere placement of the shoulder
muscle around the heart rather than from a muscular assistance.
[0008] There are a variety of devices that may be applied to the
heart for treatment of CHF. Patents owned by Abiomed (U.S. Pat.
Nos. 6,224,540; 5,800,528; 5,643,172) generally show a girdle-like
device situated to provide structure to a failing heart. U.S.
Patents owned by Acorn Cardiovascular, Inc. (U.S. Pat. Nos.
6,241,654; 6,230,714; 6,193,648; 6,174,279; 6,169,922; 6,165,122;
6,165,121; 6,155,972; 6,126,590; 6,123,662; 6,085,754; 6,077,218;
5,702,343) show various devices, also for treatment of CHF, which
typically include a mesh sock-like device placed around the
myocardial wall. U.S. Patents to Myocor, Inc. (U.S. Pat. Nos.
6,264,602; 6,261,222; 6,260,552; 6,183,411; 6,165,120; 6,165,119;
6,162,168; 6,077,214; 6,059,715; 6,050,936; 6,045,497; 5;961,440)
show devices for treatment CHF generally using components that
pierce the ventricular wall.
[0009] None of the documents mentioned above appears to suggest the
devices and methods provided for herein.
BRIEF SUMMARY OF THE INVENTION
[0010] This invention is a device and a method for reinforcing the
pericardium. Generically, it is made of at least one compliant
member having an interior surface for placement adjacent to or
spaced away from the epicardium and an exterior surface for
attachment to the interior of a pericardium. The compliant member
may be conformable in shape to at least a portion of the
epicardium.
[0011] The interior surface is adapted to inhibit adhesions or
attachment to the epicardium, e.g., via use of a material that does
not substantially permit ingrowth with or that resists ingrowth
with the epicardium. Suitable choices for materials that
functionally provide such results include various lubricious
material, perhaps polymeric, e.g., fluorocarbon polymers especially
those selected from the group consisting of
polytetrafluoroethylene, ethylene-chlorofluoroethylene, fluorinated
ethylene propylene, polychlorotrifluoroethylene, polyvinylfluoride,
and polyvinylidenefluoride and certain expanded
polytetrafluoroethylenes (ePTFE). Other suitable lubricious
polymers include those selected from the group consisting of LLDPE,
LDPE, HDPE, polypropylene, and polyamides their mixtures and
co-polymers.
[0012] The exterior surface functionally adheres to or reacts with
or ingrows with the pericardium in such a way that the resulting
pericardium-implant combination is substantially reinforced
compared to the previously existing pericardium. The outer layer,
for instance, may comprise a material for ingrowth into or with or
for attachment to or adherence with the pericardium. The exterior
surface may comprise a material that itself promotes ingrowth,
e.g., polyethylene terephthalate, polyglycolic acid, polylactic
acid, reconstituted collagen, poly-p-dioxanone,
poly(glycolide-lactide) copolymer, poly(glycolide-trimethylene
carbonate) copolymer, poly(glycolide-.epsilon.-caprolactone)
copolymer, glycolide-trimethylene carbonate triblock copolymer,
their block and random copolymers, mixtures, and alloys. Physical
mixtures of the biodegradable polymers with other substantially
non-biodegradable materials, (such as polyolefins or
polyfluorocarbons) is desired to preserve to integrity of the
flexible or compliant member. Particularly desirable are mixtures
of biodegradable and non-bio-degradable polymeric fibers, perhaps
by coweaving or other suitable manner of making an integrated
fabric.
[0013] The outer surface may further comprise a material promoting
endothelialization, such as an effective hyalonurate salt or one or
more angiogenic materials such as are listed below. Physically, the
outer surface may be an independent layer or an integrated layer, a
woven or non-woven polymeric material. The attachment to the outer
layer may be simply mechanical, and produced by, e.g., suturing or
adhesively attaching it to the pericardium. The exterior surface
may be textured to assist with ingrowth into the pericardium.
[0014] As noted above, the compliant member may comprise a separate
inner member and an outer member, e.g., where at least one of the
inner members and the outer members comprises a woven or non-woven
fabric. They may be laminated together or with an intermediate
between. In some instances, at least one, of the inner members and
the outer members is substantially non-porous, non-porous, or
non-continuous.
[0015] It is desirable that the inventive device include an
adjuster adapted for changing the compliant member size after
attachment of that compliant member to the interior of the
pericardium. The adjuster, for instance, may be a rotatable roller,
a drawstring, a band, or the like. One preferable band variation is
made up of an upper end and an apical end and has a length
extending from the upper end to the apical end and where the length
of the band is less than about 1/3 length of a heart to which it is
applied. The band may have a length substantially matching the
width of the A-V groove on that heart.
[0016] The shape of the compliant member may be that of a sack
having a closed end, particularly one having a closed end and sized
to be positioned only along and less than about 1/3 length of the
heart when positioned from the apical end. The compliant member may
be a substantially elongated member having a distal end and a
proximal end and configured to be helical upon introduction into
the region of the pericardium, perhaps having a lumen (in some
instances expandable) extending from the proximal end at least
partially to the distal end. The lumen may have at least one
orifice open to the exterior surface when the device is helically
configured in the region of the pericardium, perhaps to pass glue
or adhesive to the pericardium side of the device. In some
variations, the source of glue or adhesive also forms a component
of the inventive device.
[0017] One very desirable form of the compliant member is an
enclosure generally conforming in shape to at least a portion of an
epicardium where the enclosure has at least one rib separated by
and spaced apart by webbing. The rib may be at least one band
having an upper end and an apical end and a length extending from
the upper end to the apical end and having at least two open,
generally opposing openings. Desirably, the wound band has a length
less than about 1/3 length of a heart to which it is applied.
[0018] Preferably, the various ribs have a flexibility different
than that of the webbing. The at least one rib may have the form of
a generally helical member, perhaps ribbon-like in form. A "ribbon"
is considered to have a width-thickness ratio greater than about
two, perhaps greater than about seven. The helical member may be
inflatable over at least a portion of the enclosure, perhaps
incrementally inflatable along its length.
[0019] The compliant member may be made up of an enclosure
generally conforming in shape to at least a portion of a
pericardium and having multiple ribs extending from the upper end
to the apical end. Desirably each rib may be ribbon-like.
Alternatively, the ribs may each have a round cross section or may
have a cross section with a width-thickness ratio of two or less.
The multiple ribs may be zigzag in shape and where there are
multiple zigzag ribs having substantially adjacent points, at least
some of the adjacent points may be connected. At least some of the
multiple ribs may be joined at the apical end.
[0020] The webbing may be of a variety of forms, e.g., a woven
fabric, a woven open weave fabric, one or more ribbons extending
between at least some of the multiple ribs, one or more fibers
extending between at least some of the multiple ribs, an elastic
material, a substantially inelastic material, or the like.
[0021] The compliant member may have a longitudinal opening
extending from the upper end towards the apical end and including a
plurality of looping members situated on the upper end (like loops
on a kitchen curtain) deployable over a looping deployment tool.
The deployment tool is preferably adapted to be removable after
placement of the compliant member adjacent said pericardium and has
a connector member for separation after installation. The
invention, in some variations, includes the installation
member.
[0022] The invention includes various procedures for reinforcing
the pericardium. One procedure comprises the steps of introducing
the inventive device through a pericardium wall into a pericardial
space, desirably below the xiphoid process of a patient, and
positioning the inventive pericardial reinforcement adjacent the
pericardium. The procedure may include the step of puncturing skin
beneath the xiphoid process with a needle and an introducer and
passing the needle through the pericardium to the pericardial
space. The steps of introducing a guidewire, removing the needle,
and introducing a cannula may also be included.
[0023] Finally, the invention includes a modified pericardium
reinforced with the compliant pericardial reinforcement devices
discussed elsewhere.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is an anterior view of the heart in a human chest
showing the pericardium in particular.
[0025] FIG. 2 is a partial cross-section of the inventive
reinforcing device as deployed upon a pericardial sac and in
reference to an epicardium.
[0026] FIG. 3A shows a cross-sectional view of the compliant member
making up one variation of the invention. FIG. 3B shows a side-view
of the FIG. 3A material.
[0027] FIG. 4A shows a cross-sectional view of the compliant member
making tip one variation of the invention. FIG. 4B shows a side
view of the FIG. 4A material.
[0028] FIGS. 5 and 6 show cross-sectional views of, respectively,
mechanical fasteners and adhesives in placing the inventive device
on the pericardium.
[0029] FIGS. 7, 8, and 9 show various side-views of variations of
the invention.
[0030] FIGS. 1A, 10B, 11A, 1B show side views (FIGS. 10A and 11A)
of variations of the inventive reinforcing member and
cross-sectional views (FIGS. 10B and 11B) of those variations.
[0031] FIGS. 12, 13, and 14 show side views of variations of the
invention.
[0032] FIGS. 15A, 15B, 15C, and 15D show close-ups of various
webbing variations suitable for the inventive reinforcing
member.
[0033] FIGS. 16A, 16B, 17 A, and 17B show, respective, a side-view
of a variation of the invention device employing adhesives prior to
introduction into the pericardial sac, a cross section of that side
view, a side view of the variation after introduction to the
pericardial sac, and a cross section of that installed device.
[0034] FIG. 18 shows a side view of a variation of the inventive
device and an introducer.
[0035] FIG. 19 shows a side view of a variation of the inventive
device having a draw-string adjuster.
[0036] FIG. 20A shows a side view of a variation of the inventive
device having a roller adjuster. FIG. 20B shows a top view of the
FIG. 20A variation schematically depicting the operation of the
adjuster.
[0037] FIG. 21 shows a side view of a variation of the inventive
device also having a draw-string adjuster.
[0038] FIGS. 22A-22E show a method for introducing the inventive
device into contact with the pericardium.
DETAILED DESCRIPTION OF THE INVENTION
[0039] As noted elsewhere, this invention has several related
aspects: it is 1.) a device for reinforcing the pericardial sac
that has an inner surface that tends not to adhere to the
epicardium and an outer surface that adheres to, is inter-grown
with, or is made in some fashion to constrain expansion of some
portion of the pericardium; 2.) methods of introducing the
inventive reinforcing device to the operative site; and 3.) the
resulting modified and reinforced pericardium having the inventive
reinforcing device attached to it.
[0040] Our use of the term "compliant" and its variations are
embodied in the following: in general, the inventive reinforcing
device is constructed in such a way that it is sufficiently
compliant to be placed insubstantial contact with a portion of the
inner surface of the pericardium to allow some measure of adherence
between the two. This may mean that the device is flexible or that
a portion of the device is flexible or that a portion of the device
is comparatively stiffer than another portion or portions. The
functional result is this: the device should reinforce the
pericardium in such a way that over an extended period of time, the
size of the combination of pericardium and the reinforcing device
do not expand in a way consistent with the typical, ongoing
progress of CHF. Additionally, we use the term "substantially
non-elastic" not in an absolute sense, but simply to express the
functional concept that during the use of the device in reinforcing
the pericardium, the device is not substantially changing in size
due to the pressures placed upon it by the beating of the heart.
Some elasticity in a gross physical sense is perceived to be
inevitable.
[0041] First, in FIG. 1, the situation of a typical human heart
(100) may be seen. Of special interest here is the pericardium
(102) surrounding the epicardium (104) but separated by a small
barrier filled with a pericardial fluid (106). The pericardial sac
or the pericardium (102) approaches the diaphragm (108) closely at
the apex of the heart. In individuals who are not obese, the
distance from the exterior surface of the skin, through the
diaphragm (108), and into the pericardial sac (102) may be as short
as a couple of inches. In obese individuals, the distance can be
much greater, e.g., six inches or more. As will be discussed below,
this sub-xiphoid approach (a percutaneous route as described above,
but below the xiphoid process-not shown in FIG. 1) is highly
desirable and even preferable to "cracking the chest" to introduce
various implants into the cardiac space.
[0042] Also seen in FIG. 1, for reference are the lungs (110, 112)
and the ribs (114). Note how far below the apex at the heart (100)
the ribs extend.
[0043] FIG. 2 shows, in cross-section, a pericardium (120),
reinforced by the inventive reinforcing device (122), surrounding a
pericardial space (124) typically filled with a fluid and a heart
wall or epicardium (126).
[0044] The inventive device (122) has an inner surface (128) and an
outer surface (130). In use, the inner surface (128) remains
generally or substantially separated from the epicardium (126). In
construction, the inner surface (128) is adapted not to be
susceptible to adhesion to the epicardium. One way to prevent such
adhesion is to configure the inner surface of a material or with a
surface structure that tends not to permit adhesion with the
myocardial tissue of the epicardium (126). This function may be
carried out in several ways. For instance, the surface (128)
confronting the epicardium (126) may be coated with a slippery
material or comprise a slippery material. The device (122) may be
multilayered and comprise an independent inner layer of a slippery
material.
[0045] By the terms "adherence" and "adhesion," we mean that the
noted specific component or region of the device is substantially
locally immobile with respect to its related heart tissue. That is
to say that it may be adhesively connected to the tissue,
mechanically attached to the tissue, ingrown with the tissue,
connected using specific mechanical connectors, or other methods of
or means for preventing relative motion between the device
component and the tissue wall.
[0046] FIG. 3A depicts a cross-section of a compliant member
(150}having an inner non-adhering surface (152) and an outer
surface (154). In this variation of the invention, the inner
surface (152) is coated with a material that tends not to form
adhesions with the epicardium. The non-adhering material may be
sprayed on or infused into another substrate having a differing
proclivity for adhesion onto heart tissue. In the absence of
mechanical or chemical adhesives to the pericardial sac, the
concept for this variation is simply that there exist a
differential proclivity for formation of adhesion. The inner
surface (152) has a comparatively lower proclivity for adhesion to
cardiac tissue than does the outer surface.
[0047] Incidentally, FIGS. 3A and 3B show a typical woven fabric.
The weave need not be as loose as is shown in FIG. 3B. It is also
within the scope of this invention to use a random fabric or
"non-woven" (as it is known in the polymer industry) for the single
or multiple layers of the invention device. A non-woven material
(162) is shown in FIG. 4B in another variation of the invention for
another purpose, but may be coated or used as a laminate member for
the inventive device.
[0048] The material used that substantially prevents adhesion to
the epicardium may be one or more polymers such as
polyfluorocarbons and polyolefins selected from the group
consisting of polytetrafluoroethylene (PTFE or TFE),
ethylene-chlorofluoroethylene (ECTFE), fluorinated ethylene
propylene (FEP), polychlorotrifluoroethylene (pCTFE),
polyyinylfluoride (PVF), polyvinylidenefluoride (PVDF),
polyethylene (LDPE, LLDPE, and HDPE), and polypropylene. An
especially desirable polymer is expanded polytetrafluoroethylene
(ePTFE) that is functionally adapted to inhibit ingrowth, e.g.,
ePTFE having internodal differences less than about 40 microns.
[0049] Again, they may be applied as an emulsion, dispersion, or
solution to another substrate material or the substrate material
may instead be the substantially non-adhering material with the
other side (154) treated to improve adhesion.
[0050] FIG. 4A shows a cross-section of another variation (156) of
the inventive device in which the non-adherent surface (158) is a
layer separate from the layer (160) adjacent the pericardium. The
two layers (158) may be laminated together, if so desired. They
need not be, since the function of the non-adhering side (160) is
simply to prevent attachment of the epicardium to the inventive
device (156). Again, both layers (158; 160) may be woven,
non-woven, or a mixture as desired by the designer. FIG. 4B shows a
typical "non-woven" fabric type.
[0051] Returning to FIG. 2, the surface of the reinforcing device
(122) adjacent the pericardium (120) is, in some way, to be
generally affixed to that pericardium. FIG. 3A shows a woven fabric
member (150) having a side (154) that is adapted to biologically
mesh or to ingrow with the pericardium. The adhering surface (154)
may just as well be anon-woven surface.
[0052] As is shown in FIG. 4A, the adherent surface (160) may be an
independent structure perhaps fixedly laminated to the generally
non-adherent surface (158).
[0053] The exterior or adhering surface may comprise a material
that itself promotes ingrowth, e.g., polyethylene terephthalate,
polyglycolic acid, polylactic acid, reconstituted collagen,
poly-p-dioxanone, poly(glycolide-lactide) copolymer,
poly(glycolide-trimethyleile carbonate) copolymer,
poly(glycolide-.epsilon.-caprolactone) copolymer,
glycolide-trimethylene carbonate triblock copolymer, their block
and random copolymers, mixtures, and alloys. Biodegradable polymers
often promote growth of endothelium and neovasculature in the body.
Physical mixtures of the biodegradable polymers with other
substantially non-biodegradable materials, (such as polyolefins or
polyfluorocarbons) are desired to preserve the integrity of the
flexible or compliant member. Particularly desirable are mixtures
of biodegradable and non-biodegradable polymeric fibers, perhaps by
coweaving or other suitable manner of making an integrated fabric.
An especially desirable non-biodegradable polymer is expanded
polytetrafluoroethylene (ePTFE) that is functionally adapted to
promote ingrowth, e.g., ePTFE having internodal differences greater
than about 60 microns.
[0054] Expanded polytetrafluoroethylene (ePTFE) sheets are
available having an internodal distance gradient between the two
sides, e.g., one side at 40 microns or less and one side having
internodal distances greater than about 60 microns. Such a sheet is
highly desirable.
[0055] The adhering surface of any of the variations disclosed here
may be treated to enhance the biological bonding with the compliant
reinforcement device. The inventive device may be adapted to
promote angiogenesis adjacent the pericardium.
Angiogenesis-promoting materials, particularly those that promote
growth of microvasculature, whether synthetic or natural may be
infused into the various components, e.g., into or onto the
polymers of the inventive device adjacent the pericardium.
Angiogenic materials include, e.g., collagen, fibrinogen,
vitronectin, other plasma proteins, various appropriate growth
factors (e.g., vascular endothelial growth factor, "VEGF"), and
synthetic peptides of these and other similar proteins. Other
components having a specific role may be included, e.g., genes,
growth factors, biomolecules, peptides, oligonucleotides, members
of the integrin family, RGD-containing sequences, oligopeptides;
e.g., fibronectin, laminin, bitronectin, hyaluronic acid,
silk-elastin, elastin, fibrinogen, and the like.
[0056] Other bioactive materials which may be used in the invention
include, for example, pharmaceutically active compounds, proteins,
oligonucleotides, ribozymes, and anti-sense genes. Desirable
additions include vascular cell growth promotors such as growth
factors, growth factor receptor antagonists, transcriptional
activators, and translational promotors; vascular cell growth
inhibitors such as growth factor inhibitors, growth factor receptor
antagonists, transcriptional repressors, translational repressors,
replication inhibitors, inhibitory antibodies, antibodies directly
against growth factors, bifunctional molecules consisting of a
growth factor and a cytotoxin, bifunctional molecules consisting of
an antibody and a cytotoxin; cholesterol-lowering agents;
vasodilating agents; agents which interfere with endogenous
vasoactive mechanisms, and combinations thereof.
[0057] In addition, polypeptides or proteins that may be
incorporated into or onto the inventive device, or whose DNA can be
incorporated, include without limitation, proteins competent to
induce angiogenesis, including factors such as, without limitation,
acidic and basic fibroblast growth factors, vascular endothelial
growth factor (including VEGF-2, VEGF-3, VEGF-A, VEGF-B, VEGF-C)
hif-1 and other molecules competent to induce an upstream or
downstream effect of an angiogenic factor; epidermal growth factor,
transforming growth factor .alpha. and .beta., platelet-derived
endothelial growth factor; platelet-derived growth factor, tumor
necrosis factor .alpha., hepatocyte growth factor and insulin like
growth factor; cell cycle inhibitors including CDK inhibitors;
thymidine kinase ("TK") and other agents useful for interfering
with cell proliferation, and combinations thereof.
[0058] In any case, it is also within the scope of this invention
to utilize mechanical fasteners or adhesives to join the compliant
reinforcing member to the pericardium. For instance, FIG. 5 shows
the reinforcement (170) attached to the pericardium (172) variously
with a surgical staple (174) and a suture (176). Other mechanical
fasteners such as blind rivets (178) or the like are also suitable
and within the scope of knowledge of the worker in this art.
[0059] Similarly, FIG. 6 depicts the use of a biological adhesive
based perhaps on fibrin or polycyanoacrylate or other similarly
operating adhesives (180) to affix the reinforcing device (182) to
the pericardium (172).
[0060] Having explained the generic functioning of the respective
sides of the compliant reinforcing member, we turn now to a
description of physical variations of the reinforcing member. They
share the desirable functionality of preferably being deliverable
using percutaneous delivery methods or minimally-invasive
methods.
[0061] FIG. 7 shows one such basic form (190) in which the
compliant enclosure has a closed apical end (192) and an optional
upper end band (194). The sack (190) may be woven or non-woven. The
material used preferably has some measure of rigidity, having at
least sufficient rigidity to allow an amount of pressure against
the enclosing pericardium appropriate to begin the process of
adherence to that pericardium. This stiffness is balanced against
the need for the device (190) to be sufficiently compliant to allow
passage through a cannula, or the like, during the procedure of
introducing the device (190) into the pericardial sac.
[0062] A schematic introducer (196) is shown in this variation and
in many of the other variations discussed herein. Typically the
introducer (196) will be a wire or rod having a loop carrying the
upper end of the device, e.g., band (194) in FIG. 7, during the
introducing step. The loop may then be removed from the heart or
may remain with the device as a stiffening member.
[0063] The variation (190) shown in FIG. 7 may be sufficiently
extensive in size that it extends up to the region of the
pericardium adjacent the pulmonary arteries, etc.
[0064] FIG. 8 shows a side view of a variation of the inventive
pericardial reinforcement (200) having a generally pericardial form
due to the presence of webbing (204). Webbing (204) may be fabric,
individual threads, cords, etc--many of which are discussed
elsewhere herein, but desirably the webbing is formed in such a way
as to allow for ease of folding and conformation during delivery of
the device near and past the heart's apical end. A schematic
delivery wire or introducer (206) is shown.
[0065] FIG. 9 shows a side view of a variation of the pericardial
reinforcement device (210) that is open in the end normally near
the apical end of the heart and generally is band-shaped. Optional
upper band (212) and lower band (214) are included. These bands
(212,214) are to provide structure to the after more-loosely woven
compliant member (216) separating them. This variation (210) is
especially suitable for providing support local to the ventricular
valves, a region whose reinforcement is especially effective in
alienating congestive heart failure. This variation minimizes the
mass of material implanted into the heart region, an often
desirable result. The schematic introducer (218) is shown.
[0066] FIGS. 10A and 10B show, respectively, a side view and a top
cross-sectional view of another ribbed variation (230). As shown in
FIG. 10A, this variation (230) includes ribs (232) that extend from
an upper (but optional) band (234) to an apical end (236). As may
be seen in FIG. 10B, the ribs (232) may be semicircular in
cross-section although there is a preference for the exterior of
the ribs (232) to be a shape conformable to the pericardium, the
cross-sectional shape of the ribs is not particularly important.
The ribs (232), as shown in FIGS. 10A and 10B, may stand alone but
preferably are separated and held in place by webbing (238) of any
of the various forms discussed herein.
[0067] FIGS. 11A and 11B show, respectively, a side view and a
cross-sectional view of another ribbed variation (250). As was
noted just above, the ribs (252) are not semi-circular in
cross-section but have more of a flat aspect. In this variation,
the ribs extend to an apical and (254). A schematic introducer
(256) is shown. The ribs (252) may be separated by webbing (258) if
desired.
[0068] FIG. 12 shows a side view of a variation (260) having ribs
(262) that do not extend to the apical end, but instead stop at a
lower band (264) and extend from an upper band (266). As was the
case with the other variations of this type, the ribs may be
separated by webbing (268). An introducer (270) is shown.
[0069] FIG. 13 shows a ribbed variation (280) of the inventive
reinforcement member in which the compliant member has ribs (282)
that are zigzag in shape. This rib variation minimizes the amount
of material that is introduced as rib material but distributes the
stiffer reinforcing material around the periphery of the devices
quite nicely. The ribs (282), again, may be separated by webbing
(284) material of the type discussed elsewhere. An introducer (286)
is also shown. The ribs (282) are shown to be situated "in phase"
but need not be. Other convoluted forms to the ribs, e.g., sine
shaped ribs, -shaped ribs, etc., are also within the scope of the
invention.
[0070] FIG. 14 shows a side view of a variation (290) of the
invention where the ribs (292) are joined at their respective
apexes. The ribs (292) thereby form a continuous cage about the
reinforcing member (290). The various spaces (294) remaining
amongst the ribs (292) may be filled with webbing if so
desired.
[0071] FIGS. 15A-15D show a number of variations of the "webbing"
discussed above.
[0072] FIG. 15A shows a number of ribs (300) separated by and held
together by strands (302) of an appropriate material. The strands
(302) collectively making up the webbing may be single threads or
collections of threads making up a cord-like assemblage.
[0073] FIG. 15B shows the ribs (300) with a woven cloth (304) as
the webbing material. The relative pic value may be in a range that
extends between closed cloth to very open weave.
[0074] FIG. 15C shows the ribs (300) with anon-woven fabric (306)
having optional upper and lower bands (308).
[0075] Finally; FIG. 15D shows ribs (300) separated by webbing
(310) that is made up of a series of tapes (310) in turn formed
from a fabric, woven or non-woven.
[0076] In addition to the generally pre-formed structures discussed
above, we contemplate structures formable within the pericardial
sac.
[0077] FIGS. 16A and 16B show, respectively, a side view and a
cross-sectional view of a reinforcing device (320) prior to
introduction into the pericardium. FIGS. 17 A and 17B show,
respectively, a side view and a cross-sectional view of the FIGS.
16A and 16B device after deployment.
[0078] FIG. 16A shows a side vision of a device (320) having a
perforated side (322) with perforation (324). Perforations (324)
communicate with inflatable lumen that is not visible in FIGS. 16A
and 16B. A delivery conduit (328) is provided for introducing
suitable adhesives into the device (320) in the lumen between
perforated side (322) and back side (326 in FIG. 16B). Delivery
conduit (328) desirably is used as an introducer for placement of
the device (320) in the pericardial sac via a percutaneous or
minimally invasive procedure.
[0079] The form of the device (320) shown in FIG. 16A is adapted to
allow "corkscrewing" of the device as it is wound though the
pericardial space. In addition, the perforated side (322) is
allowed by this adaptation to migrate to the outside or pericardial
side of the resulting structure. Once the proper positioning of the
device (320) has been accomplished, adhesive (330) is brought into
the lumen between the perforated side (322) and the opposite side
(326). The adhesive flows through the perforation (324) to cause
adherence between the device (320) and the surrounding pericardial
wall.
[0080] FIG. 18 shows a variation of the reinforcing member (340)
that is not a continuous band about the heart, in that it has a
longitudinal opening from upper to apical end and a delivery
introducer (342) that may be removed after delivery of the
reinforcing member (340) to the pericardium. Optionally, the
elongate section (344) of the delivery introducer (342) may be
separately removed.
[0081] All of our variations are passive devices.
[0082] After a period of time, it may be desirable to alter the
stiffness of the inventive reinforcing device. Because the device
is preferably adherent to or ingrown with the pericardium,
replacement is not a desired step. Simple size adjustment would be.
FIGS. 19, 20A, 20B, and 21 show various features allowing for
adjustment of some size of the installed pericardial reinforcement
device.
[0083] FIG. 19 shows a simple or generic reinforcing device (350)
similar in structure and concept to that found in FIG. 9. An added
feature is the structure of the lower band (352) and its attendant
drawstring (354). The lower band (352) has a lumen that
circumscribes the lower end of the device (350). The drawstring
(354) passes through this circumscribing lumen. It is desirable to
place radio-opaque markers (386), e.g., platinum or gold bands, on
the drawstring (354) to allow for later detection and manipulation.
The concept is simple: to pull on the drawstring (354) either both
sides together or one side against the other, thereby, to cinch the
lower band into a smaller diameter. Some design thought must be had
to permit the drawstring (354) to slide within the lower band
(352), e.g., by proper choice of materials on this portion. Tugging
on the drawstrings (354) of the heart will tighten the pericardium
and provide additional firmness to that pericardium in slowing the
progression of CHF. The drawstring (354) may be situated so that it
is adjustable from within or without the pericardial space.
[0084] FIGS. 20A and 20B show a tightener variation in which the
reinforcement device (360) includes a rotatable spine (362) that is
affixed to the compliant member (364) that, in turn, is adherent to
the pericardium. Twisting of the spine (362) tightens the
reinforcement device and hence the pericardium. Desirably, the
spine (362) may be twisted from the pericardia! space near the apex
of the enclosed heart.
[0085] FIG. 20B schematically shows the twisting of spine
(362).
[0086] FIG. 21 shows a variation (370) similar in structure to that
shown in FIGS. 10A and 10B. Each of these variations includes ribs
(372 in FIG. 21 and 232 in FIGS. 10A and 10B) that meet at an apex.
The ribs (372) may be fixed together at that apex (374) or may flex
freely about that lower point. In either case, the drawstring (376)
in the lumen upper band (378) may be tightened to close the upper
band (378) and to tighten the structure of inventive device (370).
Again, use of radio-opaque markers (380) is highly desirable. The
drawstring (376) should be placed so to be accessible to the
pericardial space.
[0087] Several of the benefits extending from the inventive device
may be summarized in the following way: Our device is intended not
substantially to contact the epicardium in normal use.
Consequently, many of the problems inherent simply in the act of
contacting the myocardial tissue, e.g., arrhythmia, myocarditis,
etc., may be minimized. Because our implant is designed not
substantially to contact the epicardium, any consequent coarsening
of the epicardial tissue is lessened.
[0088] The pericardium is in a gross engineering sense, a
liquid-filled shock absorber that tends to exert a constant force
upon the epicardium that is assessable via the fluid pressure in
the pericardial space. This pressure is in some measure, related to
the fitness and strength of the pericardium. Placement of implants
upon the epicardial surface provides support to that surface, but
the support is at the cost of direct implant contact. Our device
provides the same or similar support in a much more gentle and
uniform way, by supporting the pericardium and thereby supporting
the fluid that supports the heart.
[0089] Additionally, sizing and placement of the pericardial
reinforcement is somewhat simpler in that the object of the
placement procedure is not actively beating but is only a membrane
that is passively affected by the beating muscle.
[0090] One highly desirable method for placement of the inventive
reinforcement is shown in FIGS. 22A-22E.
[0091] This inventive device is neat and, because it is situated in
contact with the pericardium, is suitable for placement via any
number of procedures, ranging from the most invasive--open chest
surgery--to those that are much less invasive. A preferred
procedure for placing the device is via a percutaneous approach
through the diaphragm beneath the xiphoid process. The procedure is
direct and uses short instruments for ease and accuracy. Such a
process is outlined in FIGS. 22A-22F.
[0092] Shown in FIG. 22A is a heart (400) surrounded by a
pericardia! space (402) holding pericardia! fluid and all is
enclosed by the pericardium (404). Also shown is the muscle sheet
known as the diaphragm (406). For the purposes of depicting the
spatial relationships in this procedure, the xiphoid process (510)
is shown in shadow. Much of the extraneous body structure not
otherwise needed for explanation of the procedure have been omitted
for clarity.
[0093] Also shown in FIG. 22A is the first step of the procedure. A
suitably large hollow needle (408) and a guidewire (410) passing
through the lumen of the needle (408) have been introduced below
the xiphoid process and through the diaphragm (406). The needle
(408) and the guidewire (410) are shown having penetrated the
pericardium (404) and having passed into the pericardial space
(402).
[0094] FIG. 22B shows that the needle has been removed from the
guidewire (410) and the distal end (412) of the guidewire (410) has
been manipulated to pass upwardly. An introducer or cannula (414)
is shown being passed up the guidewire (410).
[0095] In FIG. 22C, a cannula (420) has been placed through the
pericardium (404) and the introducer wire (422) has been inserted
and may be seen proceeding to the left of the heart. The
reinforcing device (424) begins to trail the introducer wire (422).
In this variation, the upper band (426) has a relatively rigid
connection with the introducer (422) and will tend to move the
device about the apex of the heart (400).
[0096] Some amount of manual manipulation will be necessary to keep
the upper loop (426) following "the contours of the epicardium
until it reaches its desired site as shown in FIG. 22D. A vibratory
or oscillatory motion may be desirable to urge the device to its
final spot.
[0097] In FIG. 22E, the introducer wire (422) and cannula (420)
have been removed and their access points repaired, leaving the
device (424) against the pericardia! membrane (404) for attachment,
adherence, or ingrowth.
[0098] Many alterations and modifications may be made by those of
ordinary skill in this art, without departing from the spirit and
scope of this invention. The illustrated embodiments have been
shown only for purposes of clarity and the examples should not be
taken as limiting the invention as defined in the following claims.
Which claims are intended to include all equivalents, whether now
or later devised.
* * * * *