U.S. patent application number 11/584828 was filed with the patent office on 2007-05-10 for tissue opening occluder.
This patent application is currently assigned to EV3 Endovascular, Inc.. Invention is credited to Paul R. Barratt, Jana F. Oman, Gary A. Thill, Michelle M. Young.
Application Number | 20070106327 11/584828 |
Document ID | / |
Family ID | 27498779 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070106327 |
Kind Code |
A1 |
Thill; Gary A. ; et
al. |
May 10, 2007 |
Tissue opening occluder
Abstract
A tissue opening occluder comprising first and second occluder
portions, each occluder portion including a frame structure and an
attachment structure to attach one portion to the other portion.
The frames may be utilized to constrain the tissue between the two
portions enough to restrict the significant passage of blood
therethrough. The frame portions may be covered by a fabric
suspended from a perimeter thereof. The occluder portions are
conjoined at least one point on each portion.
Inventors: |
Thill; Gary A.; (Vadnais
Heights, MN) ; Young; Michelle M.; (Ham Lake, MN)
; Oman; Jana F.; (Spring Lake Park, MN) ; Barratt;
Paul R.; (Minneapolis, MN) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
EV3 Endovascular, Inc.
|
Family ID: |
27498779 |
Appl. No.: |
11/584828 |
Filed: |
October 23, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10209797 |
Jul 30, 2002 |
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11584828 |
Oct 23, 2006 |
|
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60309337 |
Aug 1, 2001 |
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60309376 |
Aug 1, 2001 |
|
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60309418 |
Aug 1, 2001 |
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Current U.S.
Class: |
606/213 |
Current CPC
Class: |
A61B 2017/00592
20130101; A61B 90/39 20160201; A61B 2017/00597 20130101; A61B
17/0057 20130101; A61B 2017/00575 20130101; A61B 2017/00615
20130101 |
Class at
Publication: |
606/213 |
International
Class: |
A61B 17/08 20060101
A61B017/08 |
Claims
1. A method of deploying a tissue opening occluder in an opening in
a tissue wall, the method comprising: positioning a distal portion
of a catheter carrying a tissue opening occluder having an occluder
panel and a substantially planar anchor assembly extending from the
occluder panel at a location proximate an opening in a tissue wall;
deploying the occluder panel of the tissue opening occluder from
the distal portion of the catheter into engagement with a first
side of the tissue wall, the occluder panel having a first end and
a second end opposite the first end; and deploying the anchor
assembly into engagement with a second side of the tissue wall such
that the anchor assembly extends through the tissue opening and is
biased toward only one of the first end and the second end of the
occluder panel, said occluder panel and said anchor assembly being
thereby opposingly urged into engagement with the tissue wall.
2. The method of claim 1, wherein the opening in the tissue wall is
a patent foramen ovale (PFO).
3. The method of claim 2, wherein the anchor assembly is deployed
in a tunnel of the PFO.
4. The method of claim 2, further comprising conforming the
substantially planar geometry of the anchor assembly to a generally
planar geometry of the PFO tunnel.
5. The method of claim 1, wherein the anchor assembly is positioned
generally parallel with the tissue wall when fully deployed.
6. The method of claim 1, further comprising positioning the anchor
assembly such that the anchor assembly is at an angle relative to
the tissue wall of less than 15 degrees.
7. The method of claim 1, wherein the occluder panel comprises a
fabric support structure supporting a fabric on a perimeter
thereof.
8. A method of occluding an opening in a tissue wall between first
and second atria of a heart, the opening having a generally planar
geometry, the method comprising: advancing a deployment catheter
carrying a tissue opening occluder comprising an occluder panel and
an anchor assembly extending therefrom to a location proximate to
the tissue wall; deploying the occluder panel from the deployment
catheter such that the occluder panel is in engagement with one
side of the tissue wall; and deploying the anchor assembly such
that it is placed within the tissue opening and extends through the
opening between the first and second atria of the heart, the anchor
assembly having a substantially planar geometry conforming to the
generally planar geometry of the tissue opening; wherein said
anchor assembly and said occluder panel are biased to be
substantially parallel when deployed.
9. The method of claim 8, wherein the deployment catheter is
advanced to a location proximate to a patent foramen ovale
(PFO).
10. The method of claim 9, wherein the anchor assembly is deployed
such that it is positioned substantially entirely within a tunnel
of the PFO.
11. The method of claim 8, further comprising positioning the
anchor assembly such that it is at an angle relative to the tissue
wall of less than 15 degrees.
12. The method of claim 8, wherein the anchor assembly comprises a
planar wire frame anchor.
13. The method of claim 12, wherein the occluder panel and anchor
assembly are made from nitinol wire.
14. A method of occluding a patent foramen ovale (PFO) in a body of
a patient, the method comprising: delivering a tissue opening
occluder having an occluder panel and a substantially planar anchor
assembly to the PFO; and deploying the tissue opening occluder by
positioning the occluder panel in an atrium of the patient and
positioning the anchor assembly on an opposite side of a septum of
the PFO such that the anchor assembly is positioned in a tunnel of
the PFO, the substantially planar anchor assembly substantially
conforming to a generally planar geometry of the tunnel of the PFO,
wherein the occluder panel and the anchor assembly engage opposite
sides of the septum in furtherance of positioning and securing the
tissue opening occluder.
15. The method of claim 14, wherein the occluder panel is deployed
in the left atrium of the patient.
16. The method of claim 14, wherein the anchor assembly is deployed
into a position substantially parallel to a septum wall.
17. The method of claim 14, wherein the anchor assembly and the
occluder panel are biased to be substantially parallel when
deployed.
18. The method of claim 14, wherein an angle between the septum
wall and the anchor assembly when fully deployed is less than 15
degrees
19. The method of claim 14, wherein the anchor assembly further
comprises at least one anchor for anchoring the assembly with
tissue of the PFO.
20. The method of claim 14, wherein the tissue opening occluder is
delivered with a catheter.
Description
RELATED APPLICATIONS
[0001] This is a divisional application of U.S. patent application
Ser. No. 10/209,797, filed Jul. 30, 2002, which claims benefit of
U.S. Provisional Patent Application Serial Nos. 60/309,337;
60/309,376; and 60/309,418; all having a filing date of Aug. 1,
2001, all of which are hereby incorporated by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to devices for
occluding a tissue opening such as a patent foramen ovale (PFO) or
shunt in the heart, the vascular system, etc. and particularly
provides an occluder device deliverable via a catheter to the site
of a tissue opening.
[0004] 2. Description of the Related Art
[0005] The device of the subject invention, in all its embodiments,
may be utilized for the occlusion of many types of tissue openings,
such as septal defects and PFO, and the like. For the sake of
clarity, the present invention may, at times, be described
specifically in the context of occlusion of a PFO. This specific
description, however, should not be taken to limit the scope of the
possible applications of the present invention.
[0006] The term "patent foramen ovale" generally refers to the
failure to close a normal opening between the left and right atria
(i.e., upper chambers) of the heart. Typically, a foramen ovale is
a flap-like opening between the left and right atria of the heart
which persists long after birth. Commonly, the foramen ovale has
one flap extending from the top of the atrial chamber and another
flap extending from the bottom of the atrial chamber, wherein the
two flaps meet or overlap each other. Specifically, a PFO is
typically located between the atrial septum primum and secundum at
the location of the fossa ovalis. The opening provides a path to
allow blood to bypass the lungs in an unborn infant, since the
lungs are not in use during that period. The foramen ovale
typically becomes functionally closed after the birth of the infant
due to greater pressure from the increased blood flow in the left
atrium acting upon the flap. However, in humans, for example, as
many as 1 in 5 people have foramen ovale that do not fully close.
In the absence of other cardiac defects or unusual cardiac
pressures, the open foramen ovale does not present a substantial
problem. However, in patients having circulatory problems-wherein
the pressure on the right side of the heart is increased, for
example as the result of congenital heart disease, blood may begin
to flow through the foramen ovale. This result may also occur, for
example, in divers when experiencing an increase in pressure due to
being under water. The presence of a significantly large PFO, a
flap structure that cannot provide sufficient seal, or a
significant increase in pressure can cause blood to shunt across
the defect from the right atrium to the left atrium and hence on to
the left ventricle, aorta, and brain. If the defect is not closed,
the risk of stroke is increased. Shunting of blood from the left to
the right side can also have negative, consequences, such as
cardiac failure or hemoptysis.
[0007] Tissue openings have traditionally been corrected by open
heart surgery which required the surgeon to open the chest of a
patient and bypass the heart temporarily. The surgeon would then
physically cut into the heart and suture the opening closed. In the
case of larger defects, a patch of a biologically compatible
material would be sewn onto the tissue to cover the opening.
However, the risk of complications occurring during such an
intricate procedure presents substantial problems that patients
would rather avoid.
[0008] In order to avoid such complications and the long recovery
times associated with open heart surgery, a variety of
trans-catheter closure techniques have been implemented. In such
techniques, an occluding device is delivered through a catheter to
the site of the tissue opening. Once the occlusion device is
positioned adjacent the opening, it must be attached to the tissue
wall containing the opening in a manner that permits it to
effectively block the passage of blood through the opening.
Furthermore, the occlusion device must also adjust to the anatomy
or structure of the PFO, commonly a tunnel like structure, the
width and length of which varies substantially between patients. As
has been documented in the literature, the trans-catheter
techniques developed thus far have had drawbacks associated
therewith.
[0009] For example, a variety of heretofore known devices require
assembly at the situs of the tissue opening. That is to say
separable or separate halves of the device are deployed and
subsequently united so as to traverse or span the tissue opening in
furtherance of closure. Some well known devices require threading
or "buttoning" of the discrete device elements. Additionally, such
devices require special delivery and/or deployment tools, making
their utility less than desirable.
[0010] A further shortcoming in the art yet to be adequately and
fully addressed is the issue of device positioning at the situs
and, more particularly, re-positioning in furtherance of
effectuating a proper seal of the tissue opening. Also not
addressed is the ability to retrieve the device from the situs
without damage thereto. Heretofore, known devices appear to
evidence a broad functionality, namely that of occlusion, or more
pointedly, plugging a tissue opening without a full or more
developed functionality of the constituents or substructures of the
device, e.g., a device which includes a single occluder reversibly
secured in place by an anchor assembly.
[0011] Heretofore known self expanding devices tend to be
structurally complex, expensive to produce and cumbersome to load,
unload, and reliably position at the situs of a tissue opening, and
insensitive to the variable requirements of the PFO tunnel
geometry. The balance or tension between the structural integrity
of the device, its "size" (e.g., bulk, rigidity, etc.), and ability
to remain optimally positioned continues to be a critical
consideration, cardiac devices being subject to the rhythmic
pumping of the heart, on the order of 100,000 beats per day.
[0012] The present invention addresses the needs of the field, as
well as other problems associated with the prior art. The present
invention offers advantages over the prior art and solves problems
associated therewith.
SUMMARY OF THE INVENTION
[0013] The present invention is a tissue opening occluder which
preferably has first and second portions. Both portions include a
frame. One or both of the portions may have means for attaching the
two portions together. Each of the frame portions is placed or
positioned on one of opposite sides of a tissue wall to occlude the
opening enough to restrict the significant passage of blood
therethrough. One or both of the frame portions may also have a
fabric support structure and have fabric suspended from a perimeter
thereof. The fabric preferably is of such a type that it promotes
the growth of tissue on the surface of or within the fabric. The
portions may be directly attached together, attached by means of an
attachment structure that is independent of either portion, may be
conjoined at a single point or at a plurality of points, or may be
attached by their frame and/or fabric elements. One or both of the
portions may be formed in different shapes or may be identically
configured.
[0014] In a first embodiment of the subject invention, the portions
or halves of the occlusion device are configured as occluding
panels, namely reversibly expandable elements which cooperatively
engage opposing wall portions in the vicinity of the tissue defect
(e.g., structures which are positioned in each atrium). Such
occluding panels may be substantially planar or may have a
significant third dimension. A variety of linkages are contemplated
for integrating or otherwise joining the panels such that the
sought after device responsiveness is obtained.
[0015] In a first alternate embodiment of the subject invention,
one half of the occlusion device may be configured as an occluding
panel (i.e., atrium engaging element), having two or three
dimensions, while the second half may comprise a planar wire anchor
structure which is configured to resiliently occupy a body
structure, such as a PFO "tunnel," in furtherance of stabilizing
the occluder panel portion of the device. The anchoring or
positioning member may utilize one or more hook structures for
engaging tissue surrounding the opening.
[0016] In yet a further embodiment of the subject invention, the
device is adapted to be received and retained exclusively within
the PFO "tunnel," no structure thereof extending into the atrium.
The anchor structure stabilizes an occluding panel such that the
panel "bridges" the portions of the septum within the area of the
defect.
[0017] The present invention is thus an improved device over
structures known in the prior art. More specific features and
advantages obtained in view of those features will become apparent
with reference to the drawing figures and DETAILED DESCRIPTION OF
THE INVENTION.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1 and 2 are side views of tissue opening occluders of
the present invention, particularly illustrating the cooperative
engagement of a pair of occluder panels;
[0019] FIGS. 3-9 illustrate a representative variety of operative
engagements contemplated for the structures of the present
invention;
[0020] FIG. 10 illustrates a side view of an anchored occluder of
the subject invention sealing a PFO;
[0021] FIG. 10A is a plan view of the device of FIG. 10;
[0022] FIG. 11 illustrates the anchor structure of FIG. 10A;
[0023] FIG. 12-23 illustrate alternate embodiments of the device of
FIG. 10, FIG. 13 illustrating only the anchor portion of the device
in combination with linkage structure;
[0024] FIG. 24 illustrates yet a further embodiment of the tissue
opening occluder of the present invention, in side view, in a
deployed condition; and,
[0025] FIGS. 25-26 illustrate embodiments of the occluder panel of
FIG. 24.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] As a preliminary matter, the subject invention contemplates
three general configurations, several styles of each shown and
subsequently described in the figures. The first general
configuration for the tissue opening occluder (e.g., those
illustrated in FIGS. 1-9) is characterized by paired occluder
panels which are operatively joined so as to permit a high degree
of motion, including rotation. The occluder panels are positioned
within each atrium so as to "patch" (i.e., overlay) the septum in
the vicinity of the defect, each occluder panel being in relative
tension (i.e., being drawn towards each other). The second general
configuration for the tissue opening occluder (e.g., that structure
illustrated in FIGS. 10-23) is characterized by a single occluder
panel, functioning in a similar capacity as heretofore described,
anchored by a substantially planar wire structure positionable for
retention within the "tunnel" of the PFO (i.e., overlapping septal
portions). A third configuration for the tissue opening occluder
(e.g., those illustrated in FIGS. 24-26) is characterized by its
deployed, occluding position, specifically its retention within a
defect such that the device is effectively contained within a
tunnel of a PFO so as to greatly reduce, if not eliminate, passage
(i.e., shunting) of blood from the right to left atrium. Finally, a
variety of advantageous linkages, namely those of FIGS. 3-9,
facilitating operative engagement between the major structural
elements of the several embodiments, are provided.
[0027] Referring generally to FIGS. 1 and 2, there is illustrated a
first general configuration for the subject reversibly deployable
tissue opening occluder 30 which includes first and second
portions, more particularly, an occluder panel 32 and an anchor
assembly 34 extending therefrom, each of these structures being
intended to be opposingly paired about a tissue opening of a type
as illustrated in FIG. 10. The anchor assembly 34 of this general
configuration comprises a panel similar to the occluder panel,
however not necessarily identical therewith, which is joined, at
least indirectly, to the occluder panel 32 via a linkage 44. The
occluder panel 32 includes a fabric support structure 36 and fabric
38 supported by a perimeter thereof. The fabric support structure
may include the wire frame, the linkage, or both. The wire frame
can be of many shapes and is preferably made of superelastic wire,
preferably Nitinol. The wire "frames preferably have a
predetermined shape which is restored after deployment of the wire
frame through a delivery catheter. The fabric is secured to the
fabric support structure by suturing or other methods known in the
art. The fabric is biocompatible and preferably supports tissue
ingrowth so as to stabilize the implanted device at the implant
site. Suitable fabrics include polyester, ePTFE, and other
appropriate materials. Preferably, but not necessarily, the
occluder panel 32 may embrace the panel styles disclosed in U.S.
Pat. Nos. 6,214,029, 6,440,152, 6,551,344, each of which are
incorporated herein by reference. As will be later detailed, once
the occluder panel 32 is reliably positioned relative to the septal
wall (e.g., within the left atrium), it may be anchored to the
tissue wall via the anchor assembly 34 (i.e., positioning and
deployment of the proximal anchor in abutting engagement with the
septum within the right atrium), thereby eliminating the flow or
shunting of blood through the opening or passageway.
[0028] Referring now to FIGS. 3-9, a variety of linkages 44 are
illustrated for the occluder panel/anchor assembly. Each of these
structures provide resilient directional translation and rotation
for one half of the device with respect to the other. The key
consideration is the responsiveness of the occluder panel 32 with
and to, the anchor assembly 34 during engagement of the occluder
panel 32 with the tissue opening.
[0029] The linkage 44 may take the form of extra winds on conjoint
eyelets 46 (FIG. 3) and the eyelets may be enlarged. The linkage
may include one or more fibers of material such as a suture or wire
(FIG. 4-9). The suture may be a wire suture and may be made of
Nitinol. The linkage 44 may more particularly include a wire
structure such as a loop, coil, or spring, such as a coil spring or
a leaf spring. The linkage 44 may have opposing ends terminating in
loops or eyelets to facilitate connection to each of the halves of
the device. Furthermore, greater than one linkage may be provided
between the occluder panel 32 and the anchor assembly 34 (FIG. 7,
see also FIG. 1 in which the anchor assembly is configured
similarly to the occluder panel).
[0030] Referring now to FIGS. 10 and 10A, an alternate
configuration of the tissue opening occlusion device 30 of the
subject invention is illustrated in a fully deployed condition,
fully engaged with portions of a tissue wall adjacent an opening or
passage therethrough, (e.g., foramen ovale) so as to effectively
block blood flow through the passage. The reversibly deployable
tissue opening occluder 30 generally includes first and second
halves, more particularly, an occluder panel 32 and an anchor
assembly 34 extending therefrom. The occluder panel 32 includes a
fabric support structure 36 and fabric 38 (not shown in FIGS. 10
and 10A) supported by a perimeter thereof. Preferably, but not
necessarily, the occluder panel 32 may embrace the panel styles
previously noted. As will be later detailed, once the occluder
panel 32 is reliably positioned relative to the septal wall, it may
be anchored to, or at least relative to, the tissue wall via the
anchor assembly 34, thereby eliminating the flow or shunting of
blood through the opening or passageway.
[0031] The anchor assembly 34 of FIGS. 10-23 generally includes a
wire anchor element 40 of generally planar configuration adapted to
be selectively manipulatable in furtherance of positioning and
securing the occluder panel 32 at a tissue opening situs. The wire
anchor element 40, as shown, is intended to be positioned and
retained within a characteristic "tunnel" of the PFO, as for
instance by expansion of the structure into tensioned engagement
with portions of the tunnel. The wire anchor element 40, as will be
later discussed in detail, is at least indirectly linked to a
central portion 42 of the fabric support structure 36, the occluder
panel 32 and anchor assembly 34 being thereby opposingly urged into
engagement with the tissue opening in furtherance of closure of the
tissue opening or passage. As will become evident, it is preferred
that the wire anchor element 40 have a portion configured to snugly
fit against a portion of the tissue wall, and that at least a
portion of the wire anchor element 40 be wide enough to anchor or
set the occluder panel 32 in place despite the forces being applied
to the device generally by the fluid running through the structure
(e.g., heart, vessel, etc.) in which the device is placed. It is to
be further understood that the wire anchor element 40 may itself be
a fabric support structure (i.e., function to suspend fabric from
at least a perimeter thereof), to the extent that the addition or
inclusion of fabric is advantageous in furtherance of "setting," in
a long term sense, the anchoring assembly (i.e.,
pseudo-assimilation of the structure to the tissue: further
adherence of the structure to the tissue) post device deployment,
or advantageous in immediate closure of the passage such as by
clotting.
[0032] The anchor assembly 34 of the tissue opening occluder 30
further includes linkage 44 (not shown in FIGS. 10 and 10A) which
joins the wire anchor element 40 to or with the occluder panel 32.
This linkage 44 may be integral to the wire anchor element 40, as
illustrated for instance in FIGS. 10 and 11, or may be a separate,
discrete structure, see for instance FIG. 15, which is interposed
between the wire anchor element 40 and the occluder panel 32.
Generally, the functionality of the linkage is to permit a
resilient multi-directional (i.e., in the Cartesian coordinate
sense, namely the x, y, z directional senses) spacing of the device
portions. It is advantageous that the wire anchor element 40
possess a high degree of freedom with respect to its motion
relative to the occluder panel 32. In addition to the
aforementioned x, y, and z motion, the ability to account for
rotation (i.e., torsion) is desirable. It is preferable that the
linkage be capable of reversible elongation. The occluder portions
32, 34 may be attached at a single point preferably at or near the
center of the occluder panel 32, or, alternatively, conjoined at a
plurality of discrete points, located or positioned within the
bounds or adjacent the perimeter of each of the halves 32, 34
(i.e., within an area bounded by each perimeter of the physical
structures 32, 34), or on the fabric 38 as applications
warrant.
[0033] As an integral component of the wire anchor element 40, the
linkage 44, more particularly the physical point of connection of
the occluder panel 32 to the wire anchor element 40, is preferably
an eyelet 46 (i.e., a loop) as shown in FIGS. 1 and 2. Similarly,
the central portion 42 of the fabric support structure 36 of the
occluder panel 32 preferably includes eyelet 46, or a plurality of
eyelets, for engaging the linkage 44 of the anchor assembly 34. It
is to be understood that as used herein, the term "eyelet" refers
generally and broadly to a loop without limitation (e.g., round,
elongate, angular, single, multiple (i.e., coil), etc.). In
addition to convenient connection means, the eyelets impart a
further resiliency or spring-like quality to the structures into
which they are incorporated, thereby fortifying the cooperative
action of the anchor assembly with the occluder panel.
[0034] As is appreciated with reference to the figures, the planar
wire anchor element 40 preferably, but not necessarily, has a
periphery that extends out into the atria when positioned in
furtherance of device anchoring. More particularly, the wire anchor
element 40 is oriented substantially parallel to the tissue wall.
The anchor profile should be low so that tissue can grow into the
implant and so that the implant does not cause flow disturbance or
facilitate clot formation. It is preferred in these embodiments,
that the angle of difference between the tissue wall and the wire
anchor element be less than 45 degrees, but more preferably may be
less than 15 degrees. This angle of difference is preferably
measured from the central axis of the tissue wall.
[0035] Anchor shapes are provided which offer capability to conform
to the geometry of a PFO tunnel and resistance to inadvertent
ejection from the tunnel in the direction of the occluder panel.
The PFO tunnel generally ranges from 3-10 mm in width and 1-20 mm
in length and is generally flat in height with no thickness under
"at rest" conditions. Anchors such as those shown in FIGS. 12, 14,
16, 17, 21 and 22 offer superior ability to conform to different or
variable tunnel widths. Further, the generally planar geometry of
anchors shown in FIGS. 12-23 conform to the generally planar
geometry of the PFO tunnel. Further, anchors such as those shown in
FIGS. 14, 15, 17, 19 and 21 offer superior resistance to ejection
from the PFO tunnel once fully or partially deployed in the tunnel
due to a portion of the anchor frame being substantially parallel
to the occluder panel (as shown in the figures). Finally, designs
such as the anchor in FIGS. 17 and 21 provide superior
accommodation of variable PFO tunnel lengths while maintaining a
frame edge that, when deployed, will resist ejection from the
tunnel
[0036] It is further advantageous, however not necessary, that the
anchor assembly 34, more particularly the wire anchor element 40,
include one or more hooks 48 (e.g., FIGS. 16/16A) for attachment of
the anchor assembly 34 to the tissue wall. In devices so equipped,
the portion of the wire anchor element 40 having the hook or hooks
48 formed therein, or extending therefrom, will extend
substantially parallel to the tissue wall. The one or more hooks
may be formed, carried and/or arranged on or with respect to the
wire anchor element 40 in any suitable manner known in the art. For
example, as shown in FIGS. 16/16A, the wire anchor element 40 is
formed having a hook 48 on an end opposite the attachment point of
the two halves 32, 34. In this case, substantially the entire wire
anchor element 40 will be generally aligned along the surface of
the tissue wall (i.e., in conformity therewith) when the hook 48
thereof is engaged in the wall.
[0037] As previously noted, the occluder panel 32 comprises a
fabric support structure 36 and fabric 38 supported or suspended by
a perimeter thereof. The fabric support structure 36 of the
occluder panel 32 is generally flexible and elastically deformable.
Fabric 38, which may be formed of a thin, flexible material which
can be folded and pulled taut without being damaged, is suspended
or otherwise affixed to the perimeter of the fabric support
structures 36. It may be desirable to provide an excess of fabric
to the panel 32 or the anchor 40 so as to facilitate collapse of
the fabric carrying structure into a catheter.
[0038] The fabric 38 is preferably a relatively porous material.
While this may seem to contradict the purpose of the device, blood
will tend to coagulate on the latticework provided by the porous
material. Blood flow across the tissue opening is usually
substantially blocked after minimal time passage. If so desired,
the fabric 38 of the occluder panel 32 may be treated with a
thrombogenic agent to speed this natural process, or may be
impregnated with a biocompatible polymeric compound or the like to
make it relatively impervious to fluids.
[0039] The primary purpose of using a porous fabric is to
accelerate the process of permanently anchoring the device in
place. The support structures hold the fabric tautly and in
intimate contact with the surface of the tissue wall. This intimate
contact between the tissue wall and perimeter of the occluder
permits ingrowth of collagen and fibrous tissue from the tissue
wall into the fabric. Over time, the membrane resting against the
tissue wall will become securely anchored to the wall and be
covered by a layer of endothelial cells. Elastic polymeric
materials such as, for example, polyester knit, nylon,
polypropylene, polytetrafluoroethylene (e.g., TEFLON.RTM.), and
expanded polytetrafluoroethylene (e.g., GORETEX(.RTM.), as well as
natural fabrics such as silk, are suitable materials for covering
the fabric support structure 36 of the occluder panel 32.
[0040] To accommodate the need of the fabric support structure 36
to distort when retrieving the device 30 into a catheter, excess
fabric can be provided. On an area basis relative to the support
structure, an excess of fabric in the range, typically, of about
30-35 percent, and up to 50 percent, is sufficient. This range is
required because the low stretch characteristics of the fabric
prevent the support structure from collapsing in a manner suitable
to get into the catheter. However, a 30 denier polyester knit is
advantageous in that it possesses a low stretch character, is
approximately 50% less bulky than known jersey style knit patterns
which facilitates the use of smaller delivery catheters, and allows
for the device of the subject invention to be retrieved into such
catheters at forces that are not detrimental to either the catheter
or the device (e.g., a 40 mm occluder may be pulled into a 12
French catheter using a reasonable peak force of about four
pounds).
[0041] The fabric 38 may be attached to support structures 36, or
wire anchor element 40 as the case may be, by any suitable means.
For instance, the fabric 38 may be directly attached to the support
structures 36 by means of an adhesive or the like, or the periphery
of the fabric 38 may be wrapped about the support structures 36 and
the peripheral edge attached to the rest of the fabric so as to
essentially define a sleeve about the support structures 36. In the
latter instance, the sleeve may fit the support structure
relatively loosely so that the structure may move within the sleeve
with respect to the fabric. The peripheral edge of the fabric may
be affixed to the rest of the fabric sheet 38 in any suitable
fashion such as by sewing. Preferably, though, the periphery of the
fabric can be sewn to at least some portion of the perimeter
segments of the support structures 36 using a polyester,
non-adsorbable suture or the like.
[0042] The planar wire anchor element 40 and the fabric support
structure 36 are preferably formed of a flexible, elastically
deformable material such as a biocompatible metal, metal alloy or
polymer, most preferably a superelastic material. One such material
currently known in the art is a near-stoichiometric nickel/titanium
alloy, commonly referred to as Nitinol or NiTi. Such superelastic
materials may be elastically deformed to a much greater extent than
most other materials, yet substantially fully recover their
original shape when released. This permits the frame to be deformed
sufficiently for insertion into, and passage through, a
small-diameter catheter, yet automatically elastically return to
its initial shape upon exiting the catheter.
[0043] The frame portions are preferably manufactured with nitinol
wire that can be wound around the pins of a forming die and
subjected to heat treatment. The wire may be bent through greater
than 360 degrees to form the loops or eyelets. The ends of the wire
may be attached to each other in any secure fashion, such as by
means of welding, a suitable biocompatible cementitious material,
or by any means known in the art. For example, the wire ends of
each frame half can be connected with a titanium hypo tube using a
compression crimp. Titanium is more ductile than nitinol, providing
a reliable grip with excellent corrosion resistance, thereby making
this method suitable for joining the ends of the material.
Alternately, the preferred forms for the fabric support and/or the
wire anchor element may be cut out from a sheet of such
superelastic material as a single structure, by chemical etching,
punching with a suitable punch and die, or any other appropriate
forming method.
[0044] In order to enhance radiopacity so that the device can be
viewed remotely during deployment, either the fabric support
structure 36 or the wire anchor element (or both) may be provided
with a radiopaque coating, such as gold or platinum. For instance,
the wire may be plated with a thin layer of gold or platinum. For
instance, a helically wound length of a thin radiopaque wire may be
placed over the wire, alternatively, radiopaque marking bands,
which are commercially available, may be employed. By placing one
such band on segments of device structures, a physician can
remotely visualize the frame as a plurality of small bands; when
the bands are appropriately spaced from one another on a monitor,
the physician knows that the frame is properly deployed.
Alternatively, the fabric support structures can be made of wire
with a radiopaque core.
[0045] With general reference to FIGS. 12-23, alternate embodiments
of the tissue opening occluder 30 of the subject invention are
illustrated, more particularly numerous configurations for the
anchor assemblies 34 (e.g., the planar wire anchor elements 40): an
"eye" (FIGS. 12 and 13); "mushroom heads" (FIGS. 14, 15, 16, and
18); lobed elements (FIGS. 19-21); and the styles which are the
subject of FIGS. 1, 2, 17, 22 and 23. The embodiments of FIGS.
15-18 show a discrete linkage 44 interposed between the occluder
panel 32 and the anchor assembly 34 so as to define a non-stressed
spaced apart condition for said structures.
[0046] FIGS. 24-26 illustrate a further embodiment of the tissue
opening occluder of the present invention in a deployed
configuration. FIGS. 25 and 26 illustrate the construction of the
occluder panel 32. The panel 32 includes a fabric support structure
36 which is shown as having a plurality of eyelets 46 formed
therein. A fabric swatch 38 is mounted to the fabric support
structure 36 in an appropriate manner such as by means of suturing
(not shown).
[0047] FIGS. 25 and 26 illustrate an anchor element 40. As
discussed generally herein with regard to all embodiments, upon the
occluder panel 32 being deployed into position within the PFO
infudibulum, the anchor element 40 can be allowed to spring into an
expanded configuration in which it operatively functions to hold
the occluder panel 32 in position within the infudibulum.
[0048] The anchor element 40 of FIGS. 24-26 is a generally straight
wire segment which, when to be deployed from, for example, a
catheter (not shown), springs to its operational configuration at
least in secure engagement with heart tissue. In some instances,
however, the anchor element 40 would spring into, and pass through,
the heart tissue. That is the disposition illustrated in FIG.
24.
[0049] It will be understood that the fabric support structure can,
in some embodiments, comprise a single continuous wire made of
nitinol. A structure employing multiple nitinol sections, however,
can also be utilized.
[0050] The swatch of fabric is made of any appropriate material
discussed hereinbefore. In any case, the material of which it is
made will function to promote tissue growth within the PFO
infudibulum.
[0051] It will be understood that insertion of the occluder panel
32 into the PFO infudibulum will be accomplished in a manner known
in the prior art. Typically, a nitinol fabric support structure
would be positioned within a deployment catheter in a contracted
configuration. After the catheter has been inserted through a
patient's vasculature to arrive at the PFO, it can be deployed in
an appropriate manner known in the prior art. Appropriate
deployment techniques are taught in U.S. Pat. Nos. 6,214,029,
6,440,152, 6,551,344. Those techniques are hereby incorporated by
reference.
[0052] Although the foregoing has focused on application of the
present invention to occlude atrial PFO, the invention is not
limited to occluding only foramen ovale. For instance, the instant
occlusion device can be used to treat atrial septal defect,
ventricular septal defect, patent ductus arteriosus, or any other
congenital or acquired orificial or tubular communications between
vascular chambers or vessels.
[0053] While a preferred embodiment of the present invention has
been described, it should be understood that various changes,
adaptations and modifications may be made therein without departing
from the spirit of the invention. Changes may be made in details,
particularly in matters of shape, size, material, and arrangement
of parts without exceeding the scope of the invention. Accordingly,
the scope of the invention is as defined in the language of the
appended claims.
* * * * *