U.S. patent application number 13/734516 was filed with the patent office on 2013-05-16 for heart-shaped pfo closure device.
This patent application is currently assigned to W.L. Gore & Associates, Inc.. The applicant listed for this patent is W.L. Gore & Associates, Inc.. Invention is credited to Andrzej J. Chanduszko.
Application Number | 20130123808 13/734516 |
Document ID | / |
Family ID | 35426406 |
Filed Date | 2013-05-16 |
United States Patent
Application |
20130123808 |
Kind Code |
A1 |
Chanduszko; Andrzej J. |
May 16, 2013 |
Heart-Shaped PFO Closure Device
Abstract
Patent foramen ovale (PFO) closure clip include two closure
members, which may be heart shaped, joined by at least two spaced
central connecting members. Each of the at least two spaced central
connecting members is attached to each closure member at a location
on the periphery of the closure member. The connecting member may
be generally square shaped or include other shapes. The clips of
the present invention may be formed of various materials, including
metals, nonmetallic materials, bioresorbable polymers, spring
steel, shape memory materials, bioresorbable shape memory polymers,
or combinations thereof. The clips can take various forms
depending, in part, upon the distribution of force required to
close a given PFO. At least one of the closure members can include
a tissue scaffold.
Inventors: |
Chanduszko; Andrzej J.;
(Chandler, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
W.L. Gore & Associates, Inc.; |
Flagstaff |
AZ |
US |
|
|
Assignee: |
W.L. Gore & Associates,
Inc.
Flagstaff
AZ
|
Family ID: |
35426406 |
Appl. No.: |
13/734516 |
Filed: |
January 4, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11111675 |
Apr 21, 2005 |
8361110 |
|
|
13734516 |
|
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|
60565285 |
Apr 26, 2004 |
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Current U.S.
Class: |
606/142 ;
606/157 |
Current CPC
Class: |
A61B 2017/00243
20130101; A61B 2017/00575 20130101; A61B 2017/00592 20130101; A61B
17/0057 20130101; A61B 17/083 20130101; A61B 2017/00606 20130101;
A61B 2017/00867 20130101 |
Class at
Publication: |
606/142 ;
606/157 |
International
Class: |
A61B 17/00 20060101
A61B017/00; A61B 17/08 20060101 A61B017/08 |
Claims
1. A clip for closing a septal defect having a length and dividing
a left atrium and a right atrium in a mammalian heart, the clip
comprising: first and second bioresorbable closure members
configured, when deployed from a compressed to expanded form into a
septal defect to place the first member in the left atrium and the
second into the right atrium, as opposing loops in planes parallel
to one another and to the length of the defect, wherein the closure
members cooperate to apply a compressive force to the defect on
deployment; a bioresorbable tissue scaffold disposed on each
closure member; and a center joint connecting the first and second
opposed closure members, the center joint being squared for
centering of the clip within the septal defect and perpendicular to
the closure members when deployed; wherein centering and deployment
of the clip within the defect brings the tissue scaffold into
contact with the defect.
2. The clip of claim 1, wherein the bioresorbable material present
in the clip is selected from the group consisting of metals,
nonmetallic materials, bioresorbable polymers, spring steel, shape
memory materials, bioresorbable shape memory polymers, and
combinations thereof.
3. A delivery assembly comprising a catheter and the clip according
to claim 1, wherein the catheter contains the device in an
elongated form.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 11/111,675 filed Apr. 21, 2005, now pending;
which claims the benefit under 35 USC .sctn.119(e) to U.S.
Application Ser. No. 60/565,285 filed Apr. 26, 2004, now expired.
The disclosure of each of the prior applications is considered part
of and is incorporated by reference in the disclosure of this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to devices and methods that
are used to close defects, and particularly for closing a patent
foramen ovale (PFO).
[0004] 2. Background of the Invention
[0005] A PFO, illustrated in FIG. 1, is a persistent, one-way,
usually flap-like opening in the wall between the right atrium 10
and left atrium 12 of the heart. Because left atrial pressure is
normally higher than right atrial pressure, the flap formed by
septum primum 14 and septum secundum 16 usually stays closed. Under
certain conditions, however, right atrial pressure can exceed left
atrial pressure, which creates the possibility that blood could
pass from the right atrium to the left atrium through a PFO tunnel
18 and allow blood clots to enter the systemic circulation. It
would be desirable to avoid this situation.
SUMMARY OF THE INVENTION
[0006] Embodiments of the present invention provide a device for
closing septal defects, such as a patent foramen ovale (PFO). The
device has substantially circular proximal and distal
configurations connected with a center joint. In most embodiments,
the center joint has a generally square configuration. The shape of
the center joint provides for centering of the device in the
defect. The device can be made from wire, such as nitinol wire.
Pieces of wire can be connected with tubes, welds, or other joining
techniques. The device can be retrieved after deployment and
repositioned if needed. Either the distal (left atrial) clip,
proximal (right atrial) clip, or both can be covered with a tissue
scaffold to help the defect seal and to encourage tissue
ingrowth.
[0007] Embodiments of the closure device can have one or more of
the following advantages: an atraumatic shape, good embolization
resistance, an ability to conform to the anatomy (instead of the
anatomy conforming to the device, especially in the defect tunnel),
repositionable or/and removable during delivery, and a small
profile after deployment. Other benefits include small diameter
delivery sheath, ease of manufacturing, cost effectiveness, and
overall simplicity. Other features and advantages will become
apparent from the following detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a cross-sectional side view showing a patent
foreman ovale (PFO).
[0009] FIGS. 2A and 2B are front elevational and top plan views of
a device according to the present invention.
[0010] FIGS. 3A and 3B are right side elevational views of the
device as made and as positioned in a PFO, respectively.
[0011] FIG. 4 is a prospective view and FIGS. 5 and 6 are front and
rear elevational views showing the device of FIG. 2A as positioned
in a PFO.
[0012] FIGS. 7 and 8 are views of the device in an elongated form
and shown within a catheter for delivery, and FIG. 7A is a
perspective view of an alternative embodiment to FIG. 7.
[0013] FIGS. 9 and 9A are a perspective view of the device
according to another embodiment of the present invention, and an
enlarged detailed view of a portion of a that device, respectively.
FIG. 9B is a perspective view of an alternative embodiment to that
in FIG. 9.
[0014] FIG. 10 is a front elevational view of a device according to
get another embodiment of the present invention.
[0015] FIGS. 10A-10C are elevational views of alternative
configurations for a center joint in the device of FIG. 10.
[0016] FIGS. 11A-11F are fragmentary front elevational views
showing alternative loop designs.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Embodiments of the devices described here are intended to
clip together tissue flaps, and particularly to clip together
septum primum and septum secundum to minimize the flow of blood
from the right atrium to the left atrium, thereby helping to reduce
the risk of stroke. To accomplish this, the devices apply a
compressive force between septum primum and septum secundum to
bring septum primum and septum secundum together to provide a
closing effect. In at least some embodiments, the applied
compressive force draws the more flexible septum primum toward
septum secundum, thereby closing the PFO without significantly
distorting the septum. The clip can provide mechanical closure at
points of contact along the PFO such that the largest remaining
opening is reduced to a size deemed small enough to block
stroke-inducing embolic particles from crossing through the PFO
tunnel: In other embodiments, the clip provides substantially
complete closure along the entire PFO length. Because the clips do
not distort the defect in preferred embodiments, the overlapping
layers of septal tissues may themselves be used to close the defect
as they are compressed by the clip.
[0018] Referring to FIGS. 2A and 2B, a closure device 20 has a
distal loop 22, a proximal loop 24, and a center joint 26
connecting loops 22 and 24. In this embodiment, the loops are each
generally "heart-shaped" and have two lobes that come together. As
shown in FIG. 2A, there are several points in the device where
wires or portions of a wire meet. At these points, the wires can be
welded and/or clamped with a collar 28, 30, 32, and 34. Collars 28
and 30 are formed at outer vertices of loops 24 and 22,
respectively; collars 32 and 34 are provided where the lobes of the
loops come together at center joint 26.
[0019] Center joint 26 has generally four sides and is preferably
generally rectangular in shape in that it has basically four sides
with two sets of parallel sides coming together at roughly right
angles. While "rectangular" strictly might imply sharp corners, it
should be understood that the corners here can be rounded or have
other configurations as are present at the location of collars 32
and 34 as shown in FIG. 2A. The sides can be straight, but can also
have some bends or curves while the overall look is still generally
rectangular. More preferably, the center joint is generally square.
Other shapes could be used, including circular, polygonal, or some
combination of straight and curved segments. The two wire paths
from collar 32 to collar 34 preferably have about the same length,
thus making it easier to load the device in a catheter or
sheath.
[0020] FIG. 2B shows a top plan view with loops 22 and 24 that are
in substantially parallel configuration and parallel to center
joint 26 from this view. The device could have this configuration,
although it could be formed such that, in its non-deployed
configuration, loops 22 and 24 are curved in the vertical plane
such that the ends, shown at collars 28 and 30, bend to an opposite
side of a center line 31 that runs through center joint 26. In
other words, as shown by the arrows in FIG. 2B, loop 24 could start
one side of center line 31 and have its outer vertex at collar 28
on the other side of line 31, and similarly for loop 22. This
overlapping effect can help provide good compressive force,
especially for materials with less recovery. For materials with
very high recovery, such as nitinol, such a configuration might not
be desirable.
[0021] Referring to FIGS. 3A, 3B and 4-6, device 20 is shown in a
non-deployed configuration (FIG. 3A), and as deployed (FIGS. 3B and
4-6). As indicated in these views, loops 22 and 24 each have a
respective upper portion or top lobe in contact with septum
secundum 16 and a lower portion or lower lobe in contact with
septum primum 14. The loops generally define a plane that is
generally parallel to each of septum primum and septum secundum.
This configuration helps distribute compressive forces across the
applicable septum and makes the pressure less traumatic.
[0022] As shown particularly in FIGS. 5 and 6, which represent
views from the right atrium (FIG. 5) and left atrium (FIG. 6),
center joint 26 is partially on the right atrial side, partially on
the left atrial side, and partially within PFO tunnel 18 (FIG. 1)
where the flaps of septum secundum 16 (FIG. 4) and septum primum 14
(FIG. 4) overlap. The center joint could be completely within the
overlapping portions of septum primum and septum secundum.
[0023] The loops and center joint are formed with appropriate
dimensions and materials, and in such a configuration, such that
when deployed, the loops provide a compressive force that holds
together septum primum 14 and septum secundum 16.
[0024] Referring to FIGS. 7 and 8, the device can be deployed with
a delivery sheath in the generally conventional manner. FIGS. 7 and
8 show device 20 in an elongated form for delivery purposes. Device
20 can be provided with a low profile to fit within a sheath 40 and
have an end, such as at collar 28, in a contact with a connector 42
at the end of a wire 44 that is used by an operator to push the
device or hold the device as sheath 40 is retracted, i.e., the
connection allows relative movement between device 20 and sheath
40. Typically, device 20 is deployed by providing sheath 40 within
the left atrium and withdrawing sheath 40 while wire 44 and
connector 42 hold device 20 in place. As sheath 40 is withdrawn,
loop 22 opens and assumes the shape shown in FIG. 6. Sheath 40 is
further drawn back within the PFO tunnel to release center joint
26, and then is further drawn back into the right atrium to allow
loop 24 to open in the right atrium. Connector 42 can stay in
contact until the device is at a desired positioning of device 20.
If the operator is not satisfied with the positioning of device 20,
the connector can be used to pull the device or hold the device
while the sheath is pushed forward to draw the device back into the
sheath to be removed or redeployed.
[0025] FIG. 7A shows an embodiment that is similar to that of FIG.
7, except that rather than a collar 28, there is a curved portion
28' in the wire used to form loop 24. While shown as a more gradual
bend, it could have a sharper bend, such as a hairpin turn. A
curved portion without a collar could be used on the other side
where collar 30 is, and in other embodiments where a collar is
shown.
[0026] FIGS. 9 and 9A show another embodiment of the present
invention. In this embodiment, device 90 has a loop 92 for use in
the left atrium and loop 94 for use in the right atrium. A tissue
scaffold 96 is shown within loop 92 for deployment in the left
atrium, and a scaffold is shown connected to loop 94 to be released
in the right atrium. As shown in FIG. 9A, where two portions of
wire come together in loop 92, a weld 99 is formed to hold the
wires together. As also indicated here, tissue scaffold 96 is shown
attached to the wire over most of its distance up to where the
wires come together. This device would be delivered in a manner
similar to that shown in FIGS. 7 and 8 above. FIG. 9B shows a
variation of FIG. 9 in which the weld 99 between two wires is
replaced with a curved wire 99' without the weld.
[0027] Referring to FIG. 10, in another embodiment of the present
invention, a device 100 has two heart shaped loops 102 and 104,
with a center joint 106 between them. In this case, the center
joint has contact points 114, 116 for each of the loops at adjacent
corners rather than being at diagonally opposite corners as shown
in device 20 in FIG. 2A. This configuration can improve rotational
stability compared to the diagonal configuration (i.e., the device
is less likely to rotate within the PFO tunnel).
[0028] Center joint 106 has three similar sides 108a, 108b, and
108c forming a generally block-U shape. Rather than another similar
side, however, a connector 110 is provided that allows for some
flexing motion in the direction indicated by arrow 112, and that
approximately equalizes the length of the two paths between contact
points 114 and 116. These equal paths make it easier to load the
device into a sheath or catheter.
[0029] Alternative connections to connection 110 are shown in FIGS.
10A, 10B, and 10C. These figures show various alternative
configurations of wires that form loops and angles that allow some
ability for sides 108a, 108b, 108c, and 110 to pivot with respect
to one or more of the other sides, and that equalize the two path
lengths of wires between contact points 114 and 116, thereby
helping to make it easier to load the device into a sheath or
catheter when it is elongated to a smaller profile.
[0030] FIGS. 11A-11E show alternative loop configurations. These
include a generally circular configuration with two collars (FIG.
11A), a generally rectangular configuration with two collars (FIG.
11B), a heart-shape with straight lines converging on a vertex to
provide a more triangular shape (FIG. 11C) than other
configuration, such as that shown in FIG. 2A, a FIG. 8 (FIG. 11D),
a generally circular configuration with one collars (FIG. 11E), and
a generally rectangular configuration with one collar (FIG. 11F).
Other shapes could be used, although it is preferred (but not
required) that the wires do not cross in a way that would create
rubbing contact.
[0031] In most of these embodiments, a single wire could be used
with several double-backs, or multiple wires could be used and
welded or crimped together with a collar at desired locations. The
clips can be formed of metal or nonmetallic materials, including
bioresorbable polymers, spring steel, shape memory materials (e.g.,
nitinol), bioresorbable shape memory polymers, or combinations of
the foregoing materials.
[0032] Shape memory materials are useful for this application.
These materials allow the clips to resume and maintain their
intended shape following deployment in vivo. A clip may take
advantage of the thermal shape memory properties of a shape memory
material, the superelastic properties of a shape memory material,
or some combination of the two. In other particular embodiments,
the clips are cut into their desired shapes from sheets of
material, such as from bioresorbable shape memory polymers.
[0033] The first and second loops are preferably made from a
material or are configured to apply a compressive force to the
overlapping layers of septal tissue. The movement of the at least
two loops may be limited by the edges of the PFO tunnel (which is
usually between 1 mm and 20 mm wide), thereby ensuring the clip
device remains horizontally centered across the defect and
consistently applies compressive force to the septal tissues at the
locations necessary to effect closure of the defect. Accurate and
consistent application of localized force can allow the use of a
smaller closure device.
[0034] The closure loops of a clip may take various forms
depending, in part, on the distribution of force desired to effect
closure of a given defect. In this application, the term "defect"
is applied to any anatomical configuration requiring treatment. In
particular, the defect can be a PFO which may allow, or allows,
blood to flow from the right atrium to the left atrium. The shape
of each closure member determines the location(s) at which the
compressive force is applied to the overlapping layers of septal
tissue.
[0035] Any of the embodiments of the present invention can include
a tissue scaffold on one or both closure members and/or the center
joint. The tissue scaffold promotes encapsulation and
endothelialization, thereby further encouraging anatomical closure
of septum primum and septum secundum. A tissue scaffold can be
formed of any flexible, biocompatible material capable of promoting
tissue ingrowth, including but not limited to polyester fabrics,
Teflon-based materials, such as ePTFE, polyurethanes, metallic
materials, polyvinyl alcohol (PVA), extracellular matrix (ECM) or
other bioengineered material, synthetic bioabsorbable polymeric
scaffolds, other natural materials (e.g., collagen), or
combinations of these materials. Also, a tissue scaffold may be
formed of a thin metallic film or foil. The scaffold may be
attached to one or both sides of the device. A tissue scaffold or
the frame may contain drugs or biological agents to improve the
defect healing process and/or to prevent clotting.
[0036] The center joint serves a horizontal centering function.
Specifically, the connecting members may be designed to fit within
the PFO tunnel such that there is little (or no) horizontal
movement once the device is deployed. Horizontal centering is
desirable because the dynamic conditions in the heart may tend to
move the device. Other configurations, including bent or slightly
bent wires, to position the connecting members within the PFO
tunnel can be used.
[0037] The compressive force applied by the closure members of any
of the various embodiments described herein can be adjusted in a
variety of ways. For example, the thickness of a strand or wire can
be increased or decreased to adjust the compressive force. In
general (and with other design considerations similar), a thicker
strand or wire will provide higher compressive force. Additionally,
various closure member configurations may be chosen to increase the
compressive force. Generally, bends with smaller angles will
provide more compressive force. Different parts of the device can
be treated in a different manner to alter stiffness and recovery,
as described in applicable Ser. No. 10/702,717 filed Nov. 6, 2003,
which is incorporated herein by reference.
[0038] In some general respects, such as the ability to use one
wire, the devices described here have some general similarities to
some devices in application Ser. No. 10/396,253, filed Mar. 25,
2003, published as 2003/0225421, which is incorporated herein be
reference.
[0039] Having described embodiments of the present invention, it
should be apparent that the invention is capable of other and
different embodiments and may be modified in various respects, all
without departing from the scope of the invention as defined by the
appended claims. Accordingly, the foregoing drawings and
description are to be regarded as illustrative in nature and not in
a restrictive or limiting sense.
* * * * *