U.S. patent application number 11/705380 was filed with the patent office on 2007-08-23 for device with biological tissue scaffold for percutaneous closure of an intracardiac defect and methods thereof.
This patent application is currently assigned to NMT Medical, Inc.. Invention is credited to Robert M. Carr, Carol A. Devellian.
Application Number | 20070198060 11/705380 |
Document ID | / |
Family ID | 29712156 |
Filed Date | 2007-08-23 |
United States Patent
Application |
20070198060 |
Kind Code |
A1 |
Devellian; Carol A. ; et
al. |
August 23, 2007 |
Device with biological tissue scaffold for percutaneous closure of
an intracardiac defect and methods thereof
Abstract
The invention provides an intracardiac occluder, which has
biological tissue scaffolds as occlusion shells, for the
percutaneous transluminal treatment of an intracardiac defect. The
intracardiac occluder includes a proximal support structure
supporting the proximal occlusion shell and a distal support
structure supporting the distal occlusion shell. In one embodiment,
biological tissue derived from the tunica submucosa layer of the
porcine small intestine forms the occlusion shells.
Inventors: |
Devellian; Carol A.;
(Topsfield, MA) ; Carr; Robert M.; (Paradise
Valley, AZ) |
Correspondence
Address: |
Kirkpatrick & Lockhart Preston Gates Ellis LLP;(FORMERLY KIRKPATRICK &
LOCKHART NICHOLSON GRAHAM)
STATE STREET FINANCIAL CENTER
One Lincoln Street
BOSTON
MA
02111-2950
US
|
Assignee: |
NMT Medical, Inc.
Boston
MA
|
Family ID: |
29712156 |
Appl. No.: |
11/705380 |
Filed: |
February 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10453709 |
Jun 3, 2003 |
|
|
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11705380 |
Feb 12, 2007 |
|
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60385274 |
Jun 3, 2002 |
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Current U.S.
Class: |
606/213 |
Current CPC
Class: |
A61B 17/12122 20130101;
A61F 2310/00365 20130101; A61B 17/0057 20130101; A61B 2017/00575
20130101; A61B 2017/00606 20130101; A61B 2017/1205 20130101; A61B
2017/00592 20130101; A61B 17/12172 20130101 |
Class at
Publication: |
606/213 |
International
Class: |
A61B 17/03 20060101
A61B017/03 |
Claims
1-17. (canceled)
18. An intracardiac occluder for percutaneous transvascular
treatment of an intracardiac defect, comprising: a proximal support
structure supporting a proximal occlusion shell; and a distal
support structure, coupled to the proximal support structure,
supporting a distal occlusion shell, wherein at least one of the
occlusion shells comprises a biological tissue scaffold comprising
a bioengineered collagen, and wherein at least one of the support
structures is biodegradable or bioresorbable.
19. The occluder of claim 18, wherein the at least one support
structure that is biodegradable or bioresorbable is fabricated from
a biodegradable or bioresorbable polymer.
20. The occluder of claim 18, wherein the bioengineered collagen is
purified bioengineered type 1 collagen.
21. The occluder of claim 18, wherein the bioengineered collagen is
derived from tunica submucosa.
22. The occluder of claim 18, wherein the proximal support
structure comprises a plurality of outwardly extending proximal
arms and the distal support structure comprises a plurality of
outwardly extending distal arms.
23. The occluder of claim 18, wherein heparin is ionically or
covalently bound to the biological tissue scaffold.
24. The occluder of claim 18, wherein the biological tissue
scaffold is laminated to the biodegradable or bioresorbable support
structure.
25. A method for percutaneous transvascular treatment of an
intracardiac defect in a patient comprising: providing an
intracardiac occluder, comprising: a proximal support structure
supporting a proximal occlusion shell; and a distal support
structure, coupled to the proximal support structure, supporting a
distal occlusion shell, wherein at least one of the occlusion
shells comprises a biological tissue scaffold comprising a
bioengineered collagen, and wherein at least one of the support
structures is biodegradable or bioresorbable; positioning the
intracardiac occluder proximate the intracardiac defect; and
engaging the intracardiac defect with the intracardiac occluder to
substantially occlude the intracardiac defect, wherein at least one
of said support structures is biodegraded or bioresorbed.
26. The method of claim 25, wherein the at least one support
structure that is biodegradable is fabricated from a biodegradable
or bioresorbable polymer.
27. The method of claim 25, wherein engaging the intracardiac
defect comprises positioning the proximal occlusion shell and the
distal occlusion shell on different sides of the intracardiac
defect.
28. The method of claim 25, wherein the intracardiac defect is a
patent foramen ovale.
29. The method of claim 25, wherein the intracardiac defect is an
atrial septal defect.
30. The method of claim 25, wherein the intracardiac defect is a
ventricular septal defect.
31. The method of claim 25, wherein the intracardiac defect is a
left atrial appendage.
32. The method of claim 25, wherein the bioengineered collagen is
derived from a tunica submucosa layer of porcine small
intestine.
33. A method for making an intracardiac occluder for percutaneous
transluminal treatment of an intracardiac defect, comprising:
providing a support structure comprising a proximal support
structure and a distal support structure wherein at least one of
the proximal or distal support structure is biodegradable or
bioresorbable; providing first and second biological tissue
scaffolds; coupling the first biological tissue scaffold to the
proximal support structure; and coupling the second biological
tissue scaffold to the distal support structure, wherein at least
one of the first or second biological tissue scaffolds comprises a
bioengineered collagen.
34. The method of claim 33, wherein coupling the biological tissue
scaffolds comprises sewing the biological tissue scaffolds to the
biodegradable or bioresorbable support structures.
35. The method of claim 33, wherein coupling the biological tissue
scaffolds comprises laminating the biological tissue scaffolds to
the biodegradable or bioresorbable support structures.
36. The method of claim 33, wherein coupling the biological tissue
scaffolds comprises gluing the biological tissue scaffolds to the
biodegradable or bioresorbable support structures.
37. The method of claim 33, wherein the at least one support
structure that is biodegradable or bioresorbable is fabricated from
a biodegradable or bioresorbable polymer.
38. An intracardiac occluder for percutaneous transvascular
treatment of an intracardiac defect, comprising: a proximal support
structure comprising a plurality of arms and supporting a proximal
occlusion shell, said arms each comprising a biasing point
comprising three or more coils; a distal support structure
comprising a plurality of arms, the distal support structure
coupled to the proximal support structure and supporting a distal
occlusion shell, said arms each comprising a biasing point
comprising three or more coils; wherein at least one of the
occlusion shells comprises a biological tissue scaffold comprising
a bioengineered collagen, and wherein at least one of the support
structures is biodegradable or bioresorbable.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application incorporates by reference, and claims
priority to and the benefit of, U.S. provisional application Ser.
No. 60/385,274, which was filed Jun. 3, 2002.
TECHNICAL FIELD
[0002] The invention generally relates to devices and related
methods for treating intracardiac defects. More particularly, the
invention provides an intracardiac occluder with a biological
tissue scaffold, and related methods, for the percutaneous closure
of intracardiac defects.
BACKGROUND
[0003] The human heart is divided into four compartments or
chambers. The left and right atria are located in the upper portion
of the heart and the left and right ventricles are located in the
lower portion of the heart. The left and right atria are separated
from each other by a muscular wall, the intraatrial septum, while
the ventricles are separated by the intraventricular septum.
[0004] Either congenitally or by acquisition, abnormal openings,
holes, or shunts can occur between the chambers of the heart or the
great vessels, causing blood to flow therethrough. Such deformities
are usually congenital and originate during fetal life when the
heart forms from a folded tube into a four chambered, two unit
system. The deformities result from the incomplete formation of the
septum, or muscular wall, between the chambers of the heart and can
cause significant problems. Ultimately, the deformities add strain
on the heart, which may result in heart failure if they are not
corrected.
[0005] One such deformity or defect, a patent foramen ovale, is a
persistent, one-way, usually flap-like opening in the wall between
the right atrium and left atrium of the heart. Since left atrial
pressure is normally higher than right atrial pressure, the flap
typically stays closed. Under certain conditions, however, right
atrial pressure exceeds left atrial pressure, creating the
possibility for right to left shunting that can allow blood clots
to enter the systemic circulation. This is particularly worrisome
to patients who are prone to forming venous thrombus, such as those
with deep vein thrombosis or clotting abnormalities.
[0006] Nonsurgical (i.e., percutaneous) closure of patent foramen
ovales, as well as similar intracardiac defects such as atrial
septal defects, ventricular septal defects, and left atrial
appendages, is possible using a variety of mechanical closure
devices. These devices, which allow patients to avoid the potential
side effects often associated with standard anticoagulation
therapies, typically consist of a metallic structural framework
that is combined with a synthetic scaffold material. The synthetic
scaffold material encourages ingrowth and encapsulation of the
device. Current devices typically utilize a polyester fabric,
expanded polytetrafluoroethylene (ePTFE), Ivalon.RTM., or a metal
mesh as the synthetic scaffold material. Such devices suffer,
however, from several disadvantages, including thrombus formation,
chronic inflammation, and residual leaks.
SUMMARY OF THE INVENTION
[0007] The present invention provides a device for occluding
intracardiac defects. The device includes a biological tissue
scaffold, as opposed to a synthetic scaffold (e.g., a polyester
fabric, ePTFE, Ivalon.RTM., or a metal mesh) as presently used by
devices known in the art. In a preferred embodiment, the biological
tissue scaffold is fabricated from collagen. In one embodiment, a
specific type of biological tissue, derived from the tunica
submucosa layer of the porcine small intestine, forms the tissue
scaffold. As a result of this structure, the aforementioned
disadvantages associated with the devices known in the art are
minimized or eliminated.
[0008] In one aspect, the invention provides an intracardiac
occluder for percutaneous transluminal treatment of an intracardiac
defect. The intracardiac occluder includes a proximal support
structure supporting a proximal occlusion shell and a distal
support structure supporting a distal occlusion shell. The distal
support structure is coupled to the proximal support structure and
at least one of the occlusion shells includes a biological tissue
scaffold.
[0009] Various embodiments of this aspect of the invention include
the following features. The biological tissue scaffold may be a
purified bioengineered type 1 collagen that may be derived from a
tunica submucosa layer of a porcine small intestine. Further, in
one embodiment, at least one of the support structures includes a
corrosion resistant metal. Alternatively, at least one of the
support structures includes a bioresorbable polymer or a
biodegradable polymer. In yet another embodiment, the proximal
support structure includes a plurality of outwardly extending
proximal arms and the distal support structure includes a plurality
of outwardly extending distal arms.
[0010] In another aspect, the invention provides a method for
percutaneous transluminal treatment of an intracardiac defect in a
patient. The method includes providing an intracardiac occluder as
described above, positioning the intracardiac occluder proximate
the intracardiac defect, and engaging the intracardiac defect with
the intracardiac occluder to substantially occlude the intracardiac
defect.
[0011] In one embodiment of this aspect of the invention, the
intracardiac defect is engaged by positioning the proximal
occlusion shell and the distal occlusion shell on different sides
of the intracardiac defect. The intracardiac defect may be, for
example, a patent foramen ovale, an atrial septal defect, a
ventricular septal defect, or a left atrial appendage.
[0012] In yet another aspect, the invention provides a method for
making an intracardiac occluder for the percutaneous transluminal
treatment of an intracardiac defect. The method includes providing
an overall support structure and first and second biological tissue
scaffolds. The overall support structure includes a proximal
support structure and a distal support structure. The method
further includes coupling the first biological tissue scaffold to
the proximal support structure and coupling the second biological
tissue scaffold to the distal support structure. In various
embodiments of this aspect of the invention, the biological tissue
scaffolds are sewn, laminated, or glued to the support
structures.
[0013] The foregoing and other objects, aspects, features, and
advantages of the invention will become more apparent from the
following description and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In the drawings, like reference characters generally refer
to the same parts throughout the different views. Also, the
drawings are not necessarily to scale, emphasis instead generally
being placed upon illustrating the principles of the invention.
[0015] FIG. 1 is a cutaway view of a heart illustrating an
intracardiac defect.
[0016] FIG. 2A is a top plan view of an intracardiac occluder
according to an illustrative embodiment of the invention.
[0017] FIG. 2B is a cross-sectional view of the illustrative
intracardiac occluder of FIG. 2A.
[0018] FIG. 3A is a top plan view of an intracardiac occluder
according to another illustrative embodiment of the invention.
[0019] FIG. 3B is a side view of the illustrative intracardiac
occluder of FIG. 3A.
[0020] FIG. 4 is a perspective view of an intracardiac occluder
according to another illustrative embodiment of the invention.
[0021] FIGS. 5A-5E illustrate the stages, according to an
illustrative embodiment of the invention, for delivering an
intracardiac occluder to an anatomical site in the body of a
patient.
[0022] FIG. 6A illustrates the results from occluding an
intracardiac defect with an intracardiac occcluder known in the
art, 30-days after delivery of the intracardiac occluder.
[0023] FIG. 6B illustrates the results from occluding an
intracardiac defect with an intracardiac occluder according to the
invention, 30-days after delivery of the intracardiac occluder.
[0024] FIG. 7A illustrates the results from occluding an
intracardiac defect with an intracardiac occcluder known in the
art, 90-days after delivery of the intracardiac occluder.
[0025] FIG. 7B illustrates the results from occluding an
intracardiac defect with an intracardiac occcluder according to the
invention, 90-days after delivery of the intracardiac occluder.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The present invention provides an intracardiac occluder for
the repair of intracardiac defects, such as, for example, a patent
foramen ovale, an atrial septal defect, a ventricular septal
defect, and left atrial appendages. The intracardiac occluder
includes a structural framework and a biological tissue scaffold
adhered thereto.
[0027] FIG. 1 depicts a cutaway view of a heart 100. The heart 100
includes a septum 104 that divides a right atrium 108 from a left
atrium 112. The septum 104 includes a septum primum 116, a septum
secundum 120, and an exemplary intracardiac defect 124, which is to
be corrected by the intracardiac occluder of the present invention,
between the septum primum 116 and the septum secundum 120.
Specifically, a patent foramen ovale 124 is shown as an opening
through the septum 104. The patent foramen ovale 124 provides an
undesirable fluid communication between the right atrium 108 and
the left atrium 112. Under certain conditions, a large patent
foramen ovale 124 in the septum 104 would allow for the shunting of
blood from the right atrium 108 to the left atrium 112. If the
patent foramen ovale 124 is not closed or obstructed in some
manner, a patient is placed at high risk for an embolic stroke.
[0028] FIG. 2A depicts an intracardiac occluder 10 according to an
illustrative embodiment of the invention. As shown, the
intracardiac occluder 10 includes a proximal occlusion shell 18
(i.e., an occlusion shell that is closest to an operator of the
intracardiac occluder 10 (e.g., a physician)), an opposite distal
occlusion shell 20, and an overall support structure 16. The
overall support structure 16 includes a proximal support structure
24, for supporting the proximal occlusion shell 18, and a distal
support structure 34, for supporting the distal occlusion shell 20.
In one embodiment, both the proximal support structure 24 and the
distal support structure 34 include outwardly extending arms to
support each of their respective occlusion shells 18, 20. As shown
in FIG. 2A, for example, the proximal support structure 24 includes
four outwardly extending arms 26 and the distal support structure
34 similarly includes four outwardly extending arms 36. In one
embodiment, each outwardly extending arm is resiliently biased as a
result of including three or more resilient coils 43 radially
spaced from a center point 45. Alternatively, other resilient
support structures could be used. In one embodiment, the eight arms
26, 36 are mechanically secured together by wire 52. Alternatively,
other means, such as, for example, laser welding, may be used to
secure the eight arms 26, 36 together. A cross-sectional view of
the intracardiac occluder 10 illustrated in FIG. 2A, showing four
arms 26, 36, is depicted in FIG. 2B.
[0029] FIGS. 3A and 3B depict an intracardiac occluder 10'
according to another illustrative embodiment of the invention. An
overall support structure 16' forms a clip and includes a proximal
support structure 24', for supporting a proximal occlusion shell
18', and a distal support structure 34', for supporting a distal
occlusion shell 20'.
[0030] An intracardiac occluder 10'' according to yet another
illustrative embodiment of the invention is illustrated in FIG. 4.
Again, an overall support structure 16'' forms a clip and includes
a proximal support structure 24'', for supporting a proximal
occlusion shell 18'', and a distal support structure 34'', for
supporting a distal occlusion shell 20''.
[0031] Alternatively, the overall support structure 16 may assume
any shape or configuration to form the proximal support structure
24 and the distal support structure 34.
[0032] In one embodiment, the overall support structure 16 is
fabricated from a corrosion resistant metal, such as, for example,
stainless steel, nitinol, or a nickel-cobalt-chromium-molybdenum
alloy (e.g., MP35N). Alternatively, in other embodiments, the
overall support structure 16 is fabricated from bioresorbable or
biodegradeable polymers.
[0033] In accordance with the present invention, the occlusion
shells 18, 20, which are attached, as described below, to the
proximal support structure 24 and the distal support structure 34,
respectively, are made from a biological tissue scaffold. In a
preferred embodiment, the tissue scaffold is fabricated from
collagen. In one embodiment, a purified (acellular) bioengineered
type 1 collagen derived from the tunica submucosa layer of the
porcine small intestine forms the tissue scaffold. More
specifically, the tunica submucosa layer, referred to hereinafter
as the Intestinal Collagen Layer ("ICL"), is separated or
delaminated from the other layers of the porcine small intestine
(i.e., the tunica muscularis and the tunica mucosa) by any method
known in the art. For example, a Bitterling sausage casing machine
is used to perform the separation. Once mechanically separated from
the other layers, the ICL is, in one embodiment, chemically cleaned
to remove debris and other substances, other than collagen. For
example, the ICL is soaked in a buffer solution at 4 degrees
Celsius without the use of any detergents, or, alternatively, in a
second embodiment, it is soaked with NaOH or trypsin. Other
cleaning techniques known to those skilled in the art may also be
used. After cleaning, the ICL is decontaminated. Any sterilization
system for use with collagen, as known in the art, may be used. For
example, a dilute peracetic acid solution, gamma sterilization, or
electron-beam sterilization is used to decontaminate the ICL.
[0034] Alternatively, collagenous tissue from the fascia lata,
pericardium, or dura matter of pigs or other mammalian sources,
such as, for example, cows or sheep, may form the tissue scaffold.
Additionally, in making the occlusion shells 18, 20, two or more
collagen layers may be bonded together and then cross-linked to
produce a biocompatible material capable of being remodeled by the
host cells.
[0035] In one embodiment, the biological tissue scaffold is
non-porous and prevents the passage of fluids that are intended to
be retained by the implantation of the intracardiac occluder 10. In
another embodiment, heparin is ionically or covalently bonded to
the biological tissue scaffold to render it non-thrombogenic. In
yet other embodiments, proteins or cells are applied to the
biological tissue scaffold to render it non-thrombogenic and/or
accelerate the healing process. Growth factors may also be applied
to the biological tissue scaffold to accelerate the healing
process.
[0036] Referring again to FIG. 2A, the occlusion shells 18, 20 are,
in one embodiment, generally square in shape. Alternatively, the
occlusion shells 18, 20 may assume other shapes. The biological
tissue scaffold forming the occlusion shells 18, 20 is strong and
flexible. The occlusion shells 18, 20 therefore easily attach to
the overall support structure 16 and, as explained below, withstand
sheath delivery to an anatomical site in the body of a patient. In
one embodiment, the occlusion shells 18, 20 are sewn, as at 22A,
22B, with any commonly used suture material (e.g., a polyester
suture) that threads through the distal ends 54 of the respective
arms 26, 36 of the proximal support structure 24 and the distal
support structure 34. Alternatively, the occlusion shells 18, 20
are laminated, glued, or attached by, for example, hooks or thermal
welding to the proximal support structure 24 and the distal support
structure 34. In yet another embodiment, the occlusion shells 18,
20 are laminated to the overall support structure 16 and,
additionally, to one another, such that the overall support
structure 16 is encapsulated entirely within the occlusion shells
18, 20.
[0037] FIGS. 5A-5E depict the stages for delivering the
intracardiac occluder 10, according to an illustrative embodiment
of the invention, percutaneously to an anatomical site in the body
of a patient. Referring to FIG. 5A, a sheath 190 is first inserted
into the intracardiac defect 186 as is typically performed by one
skilled in the art. The intracardiac occluder 10 is then loaded
into the lumen 188 of the sheath 190 and advanced throughout the
lumen 188 until positioned at the distal end 192 of the sheath 190.
Referring to FIG. 5B, the distal occlusion shell 20 of the
intracardiac occluder 10 is released into the distal heart chamber
191 through the distal end 192 of the sheath 190. The distal
occlusion shell 20 opens automatically and resiliently. The sheath
190 is then pulled back into the proximal heart chamber 193, as
illustrated in FIG. 5C, to seat the distal occlusion shell 20
against the distal wall surface 194 of the intracardiac defect 186.
The intracardiac defect 186 is thereby occluded from the distal
side. As shown in FIG. 5D, the sheath 190 is then further withdrawn
a sufficient distance to allow the proximal occlusion shell 18 to
be released from the distal end 192 of the sheath 190. The proximal
occlusion shell 18 opens automatically and resiliently to lie
against the proximal surface 196 of the intracardiac defect 186,
occluding the intracardiac defect 186 from the proximal side. The
sheath 190 is then withdrawn from the patient's body, leaving
behind the opened intracardiac occluder 10. As shown in FIG. 5E,
the occlusion shells 18, 20 are positioned on either side of the
intracardiac defect 186 and the intracardiac occluder 10 is
permanently implanted within the body of the patient.
[0038] FIGS. 6A-6B and 7A-7B depict comparative 30-day and 90-day
results, respectively, for the percutaneous closures of
interventionally created intracardiac defects in sheep.
Specifically, FIGS. 6A and 7A depict the 30-day and 90-day results,
respectively, when an exemplary intracardiac occluder known in the
art, whose occlusion shells were fabricated from a polyester fabric
(i.e., a synthetic scaffold material), is used to occlude the
intracardiac defect. FIGS. 6B and 7B depict the 30-day and 90-day
results, respectively, when the intracardiac occluder 10 of the
instant invention, whose occlusion shells 18, 20 were fabricated
from ICL, is used to occlude the intracardiac defect.
[0039] As shown, the biological tissue scaffold of the intracardiac
occluder 10 of the present invention increases the rate of tissue
ingrowth and, consequently, decreases the time needed to completely
close the intracardiac defect. Specifically, referring now to FIG.
7B, the intracardiac occluder 10 of the present invention is barely
visible after 90-days. The surrounding tissue ingrowth nearly
completely envelopes the intracardiac occluder 10. In comparison,
referring now to FIG. 7A, the exemplary intracardiac occluder known
in the art is still clearly visible after the same period of
time.
[0040] As also shown, the intracardiac occluder 10 of the present
invention naturally adheres to, and seals completely along, the
edge of the intracardiac defect in a manner that is much improved
from the exemplary intracardiac occluder known in the art.
Additionally, in one embodiment, the biological tissue scaffold of
the intracardiac occluder 10 of the present invention is
non-porous. As a result, the intracardiac occluder 10 decreases the
likelihood of fluid (e.g., blood) leakage through the opening.
[0041] Further advantages to the intracardiac occluder 10 of the
present invention, in comparison to known intracardiac occluders,
include decreased thrombogenicity, quicker endothelialization,
superior biocompatibility, minimal foreign body reaction, decreased
inmmunological and inflammatory responses, and no fibrosis.
[0042] Variations, modifications, and other implementations of what
is described herein will occur to those of ordinary skill in the
art without departing from the spirit and the scope of the
invention as claimed. Accordingly, the invention is to be defined
not by the preceding illustrative description but instead by the
spirit and scope of the following claims.
* * * * *