U.S. patent application number 17/564547 was filed with the patent office on 2022-04-21 for left atrial appendage closure implant.
This patent application is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. The applicant listed for this patent is BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to Thyna M. Chau, Christopher J. Clark, Dennis A. Peiffer, Brian Joseph Tischler.
Application Number | 20220117608 17/564547 |
Document ID | / |
Family ID | |
Filed Date | 2022-04-21 |
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United States Patent
Application |
20220117608 |
Kind Code |
A1 |
Tischler; Brian Joseph ; et
al. |
April 21, 2022 |
LEFT ATRIAL APPENDAGE CLOSURE IMPLANT
Abstract
A left atrial appendage closure implant may include a support
frame including a first bend extending from a proximal collar to a
second bend, a first segment extending from the second bend to a
third bend, a second segment extending from the third bend to a
fourth bend, and a third segment extending from the fourth bend to
a distal collar, wherein the support frame is actuatable from a
first constrained position to a second flowering position to a
third mid-deployment position to a fourth unconstrained position.
An implant may include a self-expanding support frame having a
circumference and a central longitudinal axis, a membrane disposed
over at least a portion of the support frame, and a plurality of
anchors arranged into a first row and a second row such that the
first row and the second row form a staggered pattern about the
circumference of the support frame.
Inventors: |
Tischler; Brian Joseph; (New
Brighton, MN) ; Clark; Christopher J.; (St. Michael,
MN) ; Peiffer; Dennis A.; (Brooklyn Park, MN)
; Chau; Thyna M.; (Oakdale, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOSTON SCIENTIFIC SCIMED, INC. |
Maple Grove |
MN |
US |
|
|
Assignee: |
BOSTON SCIENTIFIC SCIMED,
INC.
Maple Grove
MN
|
Appl. No.: |
17/564547 |
Filed: |
December 29, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15493736 |
Apr 21, 2017 |
11241237 |
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17564547 |
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14057573 |
Oct 18, 2013 |
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15493736 |
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61726337 |
Nov 14, 2012 |
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International
Class: |
A61B 17/12 20060101
A61B017/12; A61B 17/00 20060101 A61B017/00 |
Claims
1. An occlusion device for an atrial appendage, the device
comprising: a proximal collar; a distal collar; and a support frame
including a plurality of struts extending between the proximal
collar and the distal collar and defining an interior volume of the
occlusion device, the plurality of struts each having a proximal
end fixed to the proximal collar and a distal end fixed to the
distal collar; wherein when in an expanded configuration, the
distal collar is positioned proximal of a distalmost extent of the
support frame; wherein the support frame has a proximal section
defining a first maximum diameter, a distal section defining a
second maximum diameter less than the first maximum diameter, and
an intermediate section between the proximal section and the distal
section, the intermediate section tapering from the first maximum
diameter to the second maximum diameter.
2. The occlusion device of claim 1, wherein the support frame is a
monolithic structure cut from a single tubular member.
3. The occlusion device of claim 2, further comprising a plurality
of anchors formed integrally with the support frame.
4. The occlusion device of claim 3, wherein the plurality of
anchors each extends radially outward from a junction of at least
two struts.
5. The occlusion device of claim 1, wherein the support frame is
self-expanding.
6. The occlusion device of claim 1, wherein the distal end of each
of the plurality of struts extends proximally to the distal
collar.
7. The occlusion device of claim 1, wherein the proximal end of
each of the plurality of struts extends proximally to the proximal
collar.
8. The occlusion device of claim 1, further comprising a filter
membrane affixed to at least the proximal section of the support
frame.
9. The occlusion device of claim 1, wherein when in the expanded
configuration, the proximal collar is positioned at or distal of a
proximalmost extent of the support frame.
10. The occlusion device of claim 1, wherein in the expanded
configuration, each strut extends radially outward from the
proximal collar in a complex curve including a first bend and a
second bend, wherein at the second bend, each strut turns distally
and radially inward.
11. The occlusion device of claim 10, wherein at the second bend as
each strut turns distally and radially inward, a cross-sectional
profile of a first segment of the strut extends distally at a first
angle of between 5 degrees to 25 degrees relative to a line
parallel to a central longitudinal axis of the support frame.
12. The occlusion device of claim 11, wherein the first segment of
the strut extends distally and radially inward from the second bend
to a third bend where the cross-sectional profile turns radially
inward at a sharper angle while still extending distally.
13. The occlusion device of claim 12, wherein a second segment of
the strut extends distally from the third bend forms a second angle
with the first segment of between 20 degrees to 65 degrees.
14. The occlusion device of claim 13, wherein the second segment
extends distally and radially inward from the third bend to a
fourth bend, and at the fourth bend, the cross-sectional profile
turns proximally and a third segment of the strut extends
proximally from the fourth bend to the distal collar.
15. An occlusion device for an atrial appendage, the device
comprising: a proximal collar; a distal collar; a self-expanding
support frame including a plurality of struts extending between the
proximal collar and the distal collar and defining an interior
volume of the occlusion device, the plurality of struts each having
a proximal strut end fixed to the proximal collar and a distal
strut end fixed to the distal collar; and a plurality of anchors
disposed on the support frame, the plurality of anchors including
hook portions extending radially outward from the support frame;
wherein when in an expanded configuration, the distal collar is
positioned within the interior volume of the occlusion device and
the proximal collar is positioned at or distal of a proximalmost
extent of the support frame; wherein when in the expanded
configuration, each strut extends radially outward from the
proximal collar in a complex curve including a first bend and a
second bend, wherein at the second bend, each strut turns distally
and radially inward forming a tapered surface extending from a
first outer diameter at a proximal section of the support frame to
a second outer diameter at a distal section of the support frame,
where the first outer diameter is larger than the second outer
diameter.
16. The occlusion device of claim 15, wherein the plurality of
anchors is arranged in a first row of anchors and a second row of
anchors such that the plurality of anchors forms a staggered
pattern about a circumference of the occlusion device.
17. The occlusion device of claim 16, wherein each of the plurality
of anchors extends radially outward from a junction of at least two
struts.
18. The occlusion device of claim 15, further comprising a filter
membrane affixed to at least the proximal section of the support
frame.
19. The occlusion device of claim 15, wherein when in the expanded
configuration, the proximal collar is positioned at or distal of
the proximalmost extent of the support frame.
20. An occlusion device for an atrial appendage, the device
comprising: a proximal collar; a distal collar; and a support frame
including a plurality of struts extending between the proximal
collar and the distal collar, the plurality of struts each having a
proximal end fixed to the proximal collar and a distal end fixed to
the distal collar; wherein when in an expanded configuration, the
distal collar is positioned proximal of a distalmost extent of the
support frame; wherein the distal end of each of the plurality of
struts extends proximally to the distal collar, and the proximal
end of each of the plurality of struts extends proximally to the
proximal collar; wherein when in the expanded configuration, each
strut extends radially outward from the proximal collar to a bend,
wherein at the bend, each strut turns and forms a first tapered
surface extending distally and radially inward, each strut forming
additional bends extending further radially inward to the distal
collar.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/493,736, filed Apr. 21, 2017, which is a continuation of
U.S. application Ser. No. 14/057,573 filed Oct. 18, 2013, which
claims priority to U.S. Provisional Ser. No. 61/726,337 filed Nov.
14, 2012. All are hereby incorporated for reference.
TECHNICAL FIELD
[0002] The disclosure relates generally to percutaneous medical
devices and more particularly to percutaneous medical devices for
implantation into the left atrial appendage (LAA) of a heart.
BACKGROUND
[0003] Atrial fibrillation (AF) is the most common sustained
cardiac arrhythmia, affecting over 5.5 million people worldwide.
Atrial fibrillation is the irregular, chaotic beating of the upper
chambers of the heart. Electrical impulses discharge so rapidly
that the atrial muscle quivers, or fibrillates. Episodes of atrial
fibrillation may last a few minutes or several days. The most
serious consequence of atrial fibrillation is ischemic stroke. It
has been estimated that up to 20% of all strokes are related to
atrial fibrillation. Most atrial fibrillation patients, regardless
of the severity of their symptoms or frequency of episodes, require
treatment to reduce the risk of stroke. The left atrial appendage
(LAA) is a small organ attached to the left atrium of the heart as
a pouch-like extension. In patients suffering from atrial
fibrillation, the left atrial appendage may not properly contract
with the left atrium, causing stagnant blood to pool within its
interior, which can lead to the undesirable formation of thrombi
within the left atrial appendage. Thrombi forming in the left
atrial appendage may break loose from this area and enter the blood
stream. Thrombi that migrate through the blood vessels may
eventually plug a smaller vessel downstream and thereby contribute
to stroke or heart attack. Clinical studies have shown that the
majority of blood clots in patients with atrial fibrillation are
found in the left atrial appendage. As a treatment, medical devices
have been developed which are positioned in the left atrial
appendage and deployed to close off the ostium of the left atrial
appendage. Over time, the exposed surface(s) spanning the ostium of
the left atrial appendage becomes covered with tissue (a process
called endothelization), effectively removing the left atrial
appendage from the circulatory system and reducing or eliminating
the amount of thrombi which may enter the blood stream from the
left atrial appendage.
[0004] A continuing need exists for improved medical devices and
methods to control thrombus formation within the left atrial
appendage of patients suffering from atrial fibrillation.
SUMMARY
[0005] A medical device for left atrial appendage closure may
include a delivery catheter having a lumen extending therethrough;
and a left atrial appendage closure implant including a proximal
collar, a distal collar, and a monolithic support frame extending
therebetween, the support frame including: a first bend extending
from the proximal collar to a second bend, a first segment
extending from the second bend to a third bend, a second segment
extending from the third bend to a fourth bend, and a third segment
extending from the fourth bend to the distal collar, wherein the
support frame is actuatable from a first constrained position to a
second flowering position to a third mid-deployment position to a
fourth unconstrained position.
[0006] A left atrial appendage closure implant may include a
self-expanding support frame having a circumference and a central
longitudinal axis, a membrane disposed over at least a portion of
the support frame, and a plurality of anchors arranged into a first
row and a second row such that the first row and the second row
form a staggered pattern about the circumference of the support
frame.
[0007] A method of manufacturing a left atrial appendage closure
implant may include the steps of: [0008] obtaining an elongate
tubular member having a lumen extending therethrough and an annular
ring member; [0009] laser cutting the tubular member to form a
proximal collar, a plurality of struts, a plurality of anchors
interspersed among the plurality of struts, and a plurality of free
distal ends; [0010] forming the plurality of struts into a lattice
of generally diamond-shaped wire portions; [0011] fixedly attaching
the plurality of free distal ends to the annular ring member;
[0012] positioning the plurality of struts such that a
cross-sectional profile of the left atrial appendage closure
implant in an unconstrained position includes a first bend
extending radially outward from the proximal collar to a second
bend, a first segment extending distally and radially inward from
the second bend to a third bend, a second segment extending
distally and radially inward from the third bend to a fourth bend,
and a third segment extending proximally and radially inward from
the fourth bend to the annular ring member; and [0013] attaching a
membrane over at least a portion of the plurality of struts such
that the plurality of anchors extends through the membrane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic partial cross-sectional view of a
heart;
[0015] FIG. 2 is a schematic partial cross-sectional view of an
example left atrial appendage;
[0016] FIGS. 3-3A illustrate an example prior art implant;
[0017] FIG. 4A is a partial cross-sectional view of the example
prior art implant of FIGS. 3-3A in a first, constrained
position;
[0018] FIGS. 4B-4D illustrate perspective views of the example
prior art implant of FIGS. 3-3A in various stages of
deployment;
[0019] FIG. 5 illustrates a portion of an example medical device
according to the present disclosure;
[0020] FIG. 6 is a partial cross-sectional view of the example
medical device of FIG. 5;
[0021] FIG. 7 is a partial cross-sectional view of the example
medical device of FIG. 5 in a first, constrained position;
[0022] FIG. 8 illustrates the example medical device of FIG. 5
partially deployed;
[0023] FIG. 9 illustrates the example medical device of FIG. 5
partially deployed;
[0024] FIG. 10 illustrates the example medical device of FIG. 5
during manufacture in a flat-pattern view;
[0025] FIG. 10A is a detailed view of a portion of the example
medical device shown in FIG. 10;
[0026] FIG. 11 illustrates a portion of the example medical device
of FIG. 5; and
[0027] FIG. 12 is a partial cross-sectional view of the example
medical device of FIGS. 5 and 11 deployed within the example left
atrial appendage of FIG. 2.
[0028] While the invention is amenable to various modifications and
alternative forms, specifics thereof have been shown by way of
example in the drawings and will be described in greater detail
below. It should be understood, however, that the intention is not
to limit the invention to the particular embodiments described. On
the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the invention.
DETAILED DESCRIPTION
[0029] For the following defined terms, these definitions shall be
applied, unless a different definition is given in the claims or
elsewhere in this specification.
[0030] The terms "upstream" and "downstream" refer to a position or
location relative to the direction of blood flow through a
particular element or location, such as a vessel (i.e., the aorta),
a heart valve (i.e., the aortic valve), and the like.
[0031] The terms "proximal" and "distal" shall generally refer to
the relative position, orientation, or direction of an element or
action, from the perspective of a clinician using the medical
device, relative to one another. While the terms are not meant to
be limiting, "proximal" may generally be considered closer to the
clinician or an exterior of a patient, and "distal" may generally
be considered to be farther away from the clinician, along the
length of the medical device.
[0032] The terms "monolithic" and "unitary" shall generally refer
to an element or elements made from or consisting of a single
structure or base unit/element. A monolithic and/or unitary element
shall exclude structure and/or features made by assembling or
otherwise joining multiple discrete elements together.
[0033] All numeric values are herein assumed to be modified by the
term "about," whether or not explicitly indicated. The term
"about", in the context of numeric values, generally refers to a
range of numbers that one of skill in the art would consider
equivalent to the recited value (i.e., having the same function or
result). In many instances, the term "about" may include numbers
that are rounded to the nearest significant figure. Other uses of
the term "about" (i.e., in a context other than numeric values) may
be assumed to have their ordinary and customary definition(s), as
understood from and consistent with the context of the
specification, unless otherwise specified.
[0034] Weight percent, percent by weight, wt %, wt-%, % by weight,
and the like are synonyms that refer to the concentration of a
substance as the weight of that substance divided by the weight of
the composition and multiplied by 100.
[0035] The recitation of numerical ranges by endpoints includes all
numbers within that range, including the endpoints (e.g. 1 to 5
includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
[0036] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" include plural referents unless
the content clearly dictates otherwise. As used in this
specification and the appended claims, the term "or" is generally
employed in its sense including "and/or" unless the content clearly
dictates otherwise.
[0037] The following description should be read with reference to
the drawings wherein like reference numerals indicate like elements
throughout the several views. The detailed description and drawings
are intended to illustrate but not limit the claimed invention.
Those skilled in the art will recognize that the various elements
described and/or shown may be arranged in various combinations and
configurations without departing from the scope of the disclosure.
The various individual elements described below, even if not
explicitly shown in a particular combination, are nevertheless
contemplated as being combinable or arrangable with each other to
form other additional embodiments or to complement and/or enrich
the described embodiment(s), as would be understood by one of
ordinary skill in the art.
[0038] The occurrence of thrombi in the left atrial appendage (LAA)
during atrial fibrillation may be due to stagnancy of the blood
pool in the LAA. The blood may still be pulled out of the left
atrium by the left ventricle, however less effectively due to the
irregular contraction of the left atrium caused by atrial
fibrillation. Therefore, instead of an active support of the blood
flow by a contracting left atrium and left atrial appendage,
filling of the left ventricle may depend primarily or solely on the
suction effect created by the left ventricle. Further, the
contraction of the left atrial appendage may not be in sync with
the cycle of the left ventricle. For example, contraction of the
left atrial appendage may be out of phase up to 180 degrees with
the left ventricle, which may create significant resistance to the
desired flow of blood. Further still, most left atrial appendage
geometries are complex and highly variable, with large irregular
surface areas and a narrow ostium or opening compared to the depth
of the left atrial appendage. These aspects as well as others,
taken individually or in various combinations, may lead to high
flow resistance of blood out of the left atrial appendage.
[0039] In an effort to reduce the occurrence of thrombi formation
within the left atrial appendage and prevent thrombi from entering
the blood stream from within the left atrial appendage, a medical
device has been developed that closes off the left atrial appendage
from the heart and/or circulatory system, thereby lowering the risk
of stroke due to thrombolytic material entering the blood stream
from the left atrial appendage.
[0040] Turning to the drawings, FIG. 1 is a partial cross-sectional
view of certain elements of a human heart 10 and some immediately
adjacent blood vessels. A heart 10 may include a left ventricle 12,
a right ventricle 14, a left atrium 16, and a right atrium 18. An
aortic valve 22 is disposed between the left ventricle 12 and an
aorta 20. A pulmonary or semi-lunar valve 26 is disposed between
the right ventricle 14 and a pulmonary artery 24. A superior vena
cava 28 and an inferior vena cava 30 return blood from the body to
the right atrium 18. A mitral valve 32 is disposed between the left
atrium 16 and the left ventricle 12. A tricuspid valve 34 is
disposed between the right atrium 18 and the right ventricle 14.
Pulmonary veins 36 return blood from the lungs to the left atrium
16. A left atrial appendage (LAA) 50 is attached to and in fluid
communication with the left atrium 16.
[0041] FIG. 2 is a partial cross-sectional view of an example left
atrial appendage 50. As discussed above, the left atrial appendage
50 may have a complex geometry and/or irregular surface area. Those
skilled in the art will recognize that the illustrated LAA is
merely one of many possible shapes and sizes for the LAA, which may
vary from patient to patient. Those of skill in the art will also
recognize that the medical devices and methods disclosed herein may
be adapted for various sizes and shapes of the LAA, as necessary. A
left atrial appendage 50 may include a generally longitudinal axis
52 arranged along a depth of a main body 60 of the left atrial
appendage 50. The main body 60 may include a lateral wall 54 and an
ostium 56 forming a proximal mouth 58. In some embodiments, a
lateral extent of the ostium 56 and/or the lateral wall 54 may be
smaller or less than a depth of the main body 60 along the
longitudinal axis 52, or a depth of the main body 60 may be greater
than a lateral extent of the ostium 56 and/or the lateral wall 54.
In some embodiments, the left atrial appendage 50 may narrow
quickly along the depth of the main body 60 or the left atrial
appendage may maintain a generally constant lateral extent along a
majority of depth of the main body 60. In some embodiments, the
left atrial appendage 50 may include a distalmost region formed or
arranged as a tail-like element associated with a distal portion of
the main body 60. In some embodiments, the distalmost region may
protrude radially or laterally away from the longitudinal axis
52.
[0042] FIGS. 3 and 3A generally illustrate an example prior art
implant 100, such as that disclosed in U.S. application Ser. No.
12/583,744, which is herein incorporated by reference. The implant
100 may generally comprise a support frame 110 partially covered by
a membrane 120, and a distal cap 130. The support frame 110 may
include proximal collar 111 and a plurality of struts forming a
lattice of generally diamond-shaped wire portions extending
therefrom. The support frame 110 may include a first row 112 of
generally diamond-shaped wire portions, a second row 114 of
generally diamond-shaped wire portions, and a third row 116 of
elongated generally diamond-shaped wire portions. The support frame
110 may terminate at its distal end in a plurality of limbs 140.
The distal cap 130 may attach to the terminating distal ends of the
limbs 140. The support frame 110 may include a plurality of barbs
150 extending radially outward from the support frame 110 to
penetrate tissue and inhibit longitudinal movement of the deployed
implant 100 in a proximal direction. The barbs 150 may be generally
arranged in a single row about the circumference of the support
frame 110 and extending distally from a distal end of the second
row 114 of diamond-shaped wire portions. The barbs 150 may each be
disposed immediately alongside one strut forming one side portion
of one elongated generally diamond-shaped wire portion of the third
row 116.
[0043] The distal cap 130 includes a central hub 132 and a
plurality of spokes 134 extending radially outward therefrom. The
spokes 134 each have a first end 136 that attaches to a
corresponding terminating distal end of one of the limbs 140. The
central hub 132 remains positioned proximal of the terminating
distal ends of the limbs 140 at all operational positions of the
implant 100. Additionally, at no point during the operation of the
implant 100 does any portion of the plurality of struts extend
distally of the terminating distal ends of the limbs 140. That is,
the terminating distal ends of the limbs 140 are the distalmost
element of the plurality of struts and/or the support frame
110.
[0044] Turning to FIGS. 4A-4D, during delivery of the example prior
art implant 100 into a left atrial appendage, the implant 100 may
be disposed within a delivery catheter 190 to collectively form a
medical device 195. The medical device 195 may be percutaneously
inserted into a patient to deliver the implant 100 to the left
atrial appendage. Initially, the implant 100 may be disposed in a
first, constrained position, such that the support frame 110 fits
within the lumen of the delivery catheter 190, as seen in FIG. 4A.
Upon reaching the left atrial appendage, the delivery catheter 190
may be withdrawn proximally to expose the implant 100. As the
delivery catheter 190 is withdrawn, the terminating distal ends of
the limbs 140 and the first ends 136 of the spokes 134 are exposed
and expand radially outward. As seen in FIG. 4B, when the barbs 150
reach the distal end of the delivery catheter 190, the terminating
distal ends of the limbs 140 and the first ends 136 have extended
radially outward to a second, flowering position. Continuing to
withdrawn the delivery catheter 190, the distal cap 130 fully
deploys radially outward, pulling the terminating distal ends of
the limbs 140 radially outward to a third, mid-deployment position,
as seen in FIG. 4C. Next, the delivery catheter 190 is completely
withdrawn from the implant 100 so that the implant 100 may assume a
fourth, expanded position where the support frame 110 may extend
radially outward from a central longitudinal axis farther than the
terminating distal ends of the limbs 140 and/or the first ends 136
of the spokes 134, as seen in FIG. 4D. The implant 100, in the
fourth expanded position, pushes outward to "drive" into the tissue
such that the tissue conforms to the shape of the outer surface of
the implant 100. Lastly, the delivery catheter 190 and/or a
delivery shaft (not shown) disposed therein may be disconnected
from the proximal collar 111 and removed from the patient.
[0045] Applicants have found that recapture of the implant may be
made easier by staggering the barbs into multiple rows such that
less distally-directed force is required for the delivery catheter
to remove any given row from the tissue of the left atrial
appendage. Additionally, changes in geometry to certain aspects of
the implant may permit the use of more-compliant struts that also
facilitate easier recapture and repositioning of the implant while
maintaining at least the same amount of radially outward force at
each of the barbs/anchors, and providing improved conformability to
and sealing with the geometry of the left atrial appendage. Further
still, changes in geometry at the distal end of the implant may
facilitate use in shorter left atrial appendages, as well as easier
and cheaper manufacturing of the implant, for example, avoiding
manual assembly of the spokes to the limbs and/or individual laser
welds to each of these joints. Accordingly, an example implant is
disclosed herein, which may incorporate some or all of these
changes.
[0046] FIG. 5 illustrates a perspective view of a portion of an
example implant 200. The implant 200 may include a self-expanding
monolithic support frame 210 extending from a proximal collar 212
to a distal collar 214. In some embodiments, the support frame 210
may include a plurality of struts forming a lattice of generally
diamond-shaped wire portions. In some embodiments, the support
frame 210 may include, generally extending from proximally to
distally, a first row 220 of generally diamond-shaped wire
portions, a second row 222 of generally diamond-shaped wire
portions adjacent the first row 220, a third row 224 of generally
diamond-shaped wire portions adjacent the second row 222, a fourth
row 226 of generally diamond-shaped wire portions adjacent the
third row 224, and a fifth row 228 of generally diamond-shaped wire
portions adjacent the fourth row 226. In some embodiments, a
plurality of legs may extend from the proximalmost and/or
distalmost row(s) of generally diamond-shaped wire portions to the
proximal and/or distal collar(s), respectively. In some
embodiments, the proximalmost and/or distalmost row(s) of generally
diamond-shaped wire portions may be attached directly to the
proximal and/or distal collar(s), respectively. As will be
appreciated by the skilled artisan, additional or fewer rows of
generally diamond-shaped wire portions may be included in the
support frame 210. Increasing the number of rows of generally
diamond-shaped wire portions may permit a thinner strut thickness
to be used, which may result in greater flexibility, compliance,
and conformability of the plurality of struts and/or the support
frame 210. In other words, when deployed, the support frame 210 may
substantially conform to an internal geometry and/or shape of the
lateral wall of the left atrial appendage, rather than forcing the
lateral wall to conform to the shape of the support frame.
[0047] In some embodiments, the support frame 210 may include a
plurality of anchors 250 provided to secure the implant 200 to the
lateral wall of the left atrial appendage after deployment and
thereby inhibit proximal movement of the implant 200 relative to
the left atrial appendage. In some embodiments, the plurality of
anchors 250 may be arranged into a first row 252 of anchors and a
second row 254 of anchors disposed proximally of the first row 252
of anchors, wherein the first row 252 of anchors and the second row
254 of anchors cooperate to form a staggered pattern about the
circumference of the support frame 210. Each of the plurality of
anchors 250 may extend distally from a strut node junction 256,
such that a hook portion of each of the plurality of anchors 250 is
positioned within an interior of one generally diamond-shaped wire
portion, spaced apart from the adjacent struts. While not
explicitly shown, additional rows or other alternate arrangements
of the plurality of anchors 250 are also possible. In some
embodiments, the plurality of anchors 250 may be equally spaced
apart from each other. In some embodiments, the plurality of
anchors 250 may be spaced an unequal intervals or distances from
each other. In some embodiments, the staggered pattern may be
uniform, such that angles and distances between adjacent anchors
are the same. In some embodiments, the staggered pattern may be
non-uniform, such that some or all angles and distances between
adjacent anchors are different. The staggered pattern may provide
improved fixation strength, improved apposition to adjacent tissue,
a reduced profile in a first, constrained position, reduced force
required to remove the plurality of anchors 250 from the tissue
(compared to placing all of the anchors in a single row) since only
a portion of the total anchors is removed at a time, and reduced
force required to retrieve the implant 200 back into a delivery
catheter for repositioning (compared to having all of the anchors
in a single row). Transition of the implant 200 from the first,
constrained position to a second, flowering position to a third,
mid-deployment position to a fourth, unconstrained position will be
described in more detail below.
[0048] FIG. 6 illustrates a cross-sectional view of a profile of
the implant 200 and/or the support frame 210 in a fourth,
unconstrained position. In the cross-sectional view, certain
features of the profile can be described. In the fourth,
unconstrained position, the profile extends distally from the
proximal collar 212 and curves radially outward at a first bend 240
adjacent the proximal collar 212. The first bend 240 forms a
serpentine-like S-shape as the profile extends radially outward to
a second bend 242. At the second bend 242, the profile turns
distally and radially inward, such that a first segment 270 of the
profile forms a first angle 260 with a reference plane tangent to
the second bend 242 and parallel to a central longitudinal axis of
the implant 200. In some embodiments, the first angle 260 may be in
a range from about 5 degrees to about 25 degrees, or about 10
degrees to about 20 degrees. In some embodiments, the second bend
242 may include a short generally straight segment (about 0.025
inches to about 0.150 inches long) extending distally along the
reference plane and an intermediate bend turning radially inward,
such that the first segment 270 extends distally and radially
inward from the intermediate bend. The first segment 270 extends
distally and radially inward from the second bend 242 (and/or the
intermediate bend) to a third bend 244, where the profile turns
radially inward at a sharper angle while still extending distally,
such that a second segment 272 of the profile forms a second angle
262 with the first segment 270 of the profile (and/or a reference
plane tangent thereto). In some embodiments, the second angle 262
may be in a range from about 20 degrees to about 65 degrees, about
30 degrees to about 60 degrees, or about 40 degrees to about 50
degrees. The second segment 272 extends distally and radially
inward from the third bend 244 to a fourth bend 246 adjacent the
distal collar 214. At the fourth bend 246, the profile turns
proximally and continues radially inward to the distal collar 214,
such that a third segment 274 of the profile (and/or a reference
plane tangent thereto) forms a third angle 264 with the central
longitudinal axis. In some embodiments, the third angle 264 may be
in a range from about 35 degrees to about 75 degrees, about 40
degrees to about 65 degrees, or about 45 degrees to about 60
degrees. The third segment 274 extends proximally and radially
inward from the fourth bend 246 to the distal collar 214. The first
segment 270 may have a first length, the second segment 272 may
have a second length, and the third segment 274 may have a third
length. The length of the second segment 272 and the length of the
third segment 274 may be compared as a ratio. In some embodiments,
the ratio of the length of the second segment 272 to the length of
the third segment 274 (i.e., second length divided by third length)
may be about 0.850 to about 2.160, about 1.000 to about 1.600, or
about 1.100 to about 1.300. As may be seen from the profile
illustrated in FIG. 6, the distal ends of the plurality of struts
of the support frame 210 (at the distal collar 214) may be disposed
proximal of a distalmost portion of the plurality of struts of the
support frame 210 and/or the implant 200. In some embodiments, an
overall length of the implant 200 from a proximalmost portion to a
distalmost portion, as measured along a line parallel to the
central longitudinal axis, may be from about 0.800 inches to about
0.900 inches, or about 0.830 inches, in the fourth, unconstrained
position. In some embodiments, a center of a radius forming the
third bend 244 may be located, as measured along a line parallel to
the central longitudinal axis, about 0.050 inches to about 0.360
inches, or about 0.130 inches to about 0.240 inches, or about 0.160
to about 0.180 inches proximal of the distalmost portion, in the
fourth, unconstrained position. Additional constructional details
may be found with the discussion directed to FIGS. 10 and 10A
below.
[0049] Turning to FIGS. 7-9, the implant 200 is illustrated in
different stages of deployment. During delivery of the implant 200
to a left atrial appendage, the implant 200 may be disposed within
a lumen of a delivery catheter 290 to collectively form a medical
device 295. The medical device 295 may be percutaneously inserted
into a patient to deliver the implant 200 to the left atrial
appendage. Initially, the implant 200 may be disposed in a first,
constrained position, with the first bend 240, the second bend 242,
and the third bend 244 substantially straightened into an elongated
shape such that the support frame 210 fits within the lumen of the
delivery catheter 290 with the second segment 272 and the third
segment 274 generally parallel to each other, as seen in FIG. 7. A
delivery shaft (not shown) disposed within the lumen of the
delivery catheter 290 may be removably connected to the implant 200
at the proximal collar 212. Upon reaching the left atrial
appendage, the delivery catheter 290 may be withdrawn proximally
while the delivery shaft is held stationary, or the delivery shaft
may be advanced distally while the delivery catheter 290 is held
stationary (i.e., relative movement between the delivery catheter
and the delivery shaft may be used), to expose the implant 200
within the left atrial appendage. As the delivery catheter 290 is
withdrawn, the fourth bend 246 extends from a distal end of the
delivery catheter 290 first with the distal collar 214 disposed
proximal of the fourth bend 246.
[0050] As the delivery catheter 290 is withdrawn, the support frame
210 is exposed and expands radially outward slightly at the fourth
bend 246. Next, as seen in FIG. 8, as the third bend 244 exits the
delivery catheter 290, or about when the plurality of anchors 250
initially begins to exit the distal end of the delivery catheter
290, the fourth bend 246 is opened compared to the first,
constrained position, and the second segment 272 and the third bend
244 are translated radially outward compared to the first,
constrained position, such that the second segment 272 angles
distally and radially inward from the third bend 244 toward the
fourth bend 246 to define a second, flowering position, wherein the
exposed support frame 210 generally resembles a tulip. In the
second, flowering position, the implant 200 is partially disposed
within the lumen of the delivery catheter 290, with a portion of
the first segment 270 and the second bend 242 remaining positioned
within the lumen of the delivery catheter 290. In the second,
flowering position, the first row 252 of anchors 250 may be
disposed outside of the lumen of the delivery catheter 290 and the
second row 254 of anchors 250 may be disposed inside of the lumen
of the delivery catheter 290. In the second, flowering position,
the plurality of anchors 250 may be prevented from engaging
surrounding tissue (i.e., the lateral wall) of the left atrial
appendage. At this stage of deployment, positioning of the implant
200 within the left atrial appendage may be adjusted without having
to remove anchors from tissue.
[0051] Continuing to withdraw the delivery catheter 290, a proximal
end of the second segment 272 and the third bend 244 is translated
radially outward and distally relative to the fourth bend 246
(and/or compared to the second, flowering position) to a third,
mid-deployment position. In the third, mid-deployment position, the
third bend 244 constitutes a portion of the support frame 210 that
defines a lateralmost extent from the central longitudinal axis, as
seen in FIG. 9. Similarly, the fourth bend 246 widens or opens
laterally as the third bend 244 translates distally. In the third,
mid-deployment position, the first segment 270 extends distally and
radially outward from the second bend 242 toward the third bend
244. In the third, mid-deployment position, the second segment 272
extends less distally (i.e. extends a shorter longitudinal
distance) and more radially inward (i.e., extends along a greater
lateral or radial distance from the central longitudinal axis) from
the second bend 242 toward the third bend 244 than in the second,
flowering position. In the third, mid-deployment position, the
first row 252 of anchors 250 may be disposed outside of the lumen
of the delivery catheter 290 and the second row 254 of anchors 250
may be disposed outside of the lumen of the delivery catheter 290.
In the third, mid-deployment position, the first row 252 of anchors
250 may engage tissue (i.e., the lateral wall) of the left atrial
appendage sufficiently to be effective, and the second row 254 of
anchors 250 may or may not engage tissue of the left atrial
appendage. At this stage of deployment, positioning of the implant
200 within the left atrial appendage may be adjusted by removing
the first row 252 of anchors 250 from tissue prior to adjustment.
For a given quantity of anchors, having more than one row of
anchors requires less axially-directed force to remove each
individual row of anchors from the tissue than having all of the
anchors in a single row.
[0052] Next, the delivery catheter 290 is completely withdrawn from
the implant 200 so that the implant 200 is disposed outside of the
delivery catheter 290 and may assume a fourth, unconstrained
position where the support frame 210 at the second bend 242 may
extend laterally or radially outward from the central longitudinal
axis farther than at the third bend 244, as seen in FIGS. 5 and 6,
to define a widest lateral extent of the implant 200. In the
fourth, unconstrained position, the implant 200 may assume the
profile discussed above with respect to FIGS. 5 and 6. During use
and implantation, the implant 200, in some embodiments, may assume
a deployed position wherein the implant 200 substantially conforms
to the geometry of the left atrial appendage, as illustrated in
FIG. 12. Lastly, the delivery catheter 190 and/or a delivery shaft
(not shown) slidably disposed therein may be disconnected from the
proximal collar 111 and removed from the patient.
[0053] FIG. 10 illustrates the support frame 210 in an unrolled 2-D
flat-pattern view, as cut from a tubular member, such as a metallic
hypotube, or other suitable starting substrate. In some
embodiments, the monolithic support frame 210 may be laser cut from
a single tubular member. The skilled artisan will recognize that
other manufacturing methods known in the art may be used including,
but not limited to, machining, chemical etching, water cutting,
EDM, etc. In some embodiments, the proximal collar 212 may be
integrally formed with the support frame 210 and/or the plurality
of struts. In some embodiments, after cutting the support frame
210, a plurality of free distal ends 202 may be fixedly attached to
the distal collar 214. In some embodiments, the distal collar 214
may be formed as an annular ring member having an outer diameter
smaller than an outer diameter of the tubular member and/or the
proximal collar 212, for example, as seen in FIG. 7. The plurality
of free distal ends 202 may be inserted into an interior of the
distal collar 214 and fixedly attached thereto, for example, by
adhesive(s), welding or soldering, friction fit, or other
mechanical means. In some embodiments, the plurality of free distal
ends 202 may be formed and inserted into a distal end of the distal
collar 214, such that the plurality of struts extends distally from
the distal collar 214. In some embodiments, a portion of the
plurality of free distal ends 202 may extend through and/or
proximally of the distal collar 214. In other words, the distal
collar 214 may be disposed within an interior of the implant 200.
The smaller outer diameter of the distal collar 214 facilitates a
reduced profile in the first, constrained position.
[0054] FIG. 10A shows a detailed view of a portion of the support
frame 210 illustrated in FIG. 10. In the portion shown, one can see
how the first row 252 and the second row 254 of anchors 250 may be
formed. In some embodiments, such as shown in FIG. 10A, the
plurality of anchors 250 may be integrally formed with the
plurality of struts of the support frame 210 from a single tubular
member, such that the plurality of anchors 250 is unitary with the
support frame 210. In some embodiments, the plurality of anchors
250 may be manufactured separately and added at a later time, such
as by adhesive(s), welding or soldering, or other known attachment
means. Subsequent forming, bending, heat-treating, and/or other
procedures may be performed on the support frame 210 in order to
achieve a desired profile or shape, such as that shown in FIG.
6.
[0055] In some embodiments, a method of manufacturing the implant
200 may include the steps of: [0056] obtaining an elongate tubular
member having a lumen extending therethrough and an annular ring
member; [0057] laser cutting the tubular member to form a proximal
collar, a plurality of struts, a plurality of anchors interspersed
among the plurality of struts, and a plurality of free distal ends,
as a single monolithic structure; [0058] forming the plurality of
struts into a lattice of generally diamond-shaped wire portions;
[0059] fixedly attaching the plurality of free distal ends to the
annular ring member; [0060] positioning the plurality of struts
such that a cross-sectional profile of the left atrial appendage
closure implant in an unconstrained position includes a first bend
extending radially outward from the proximal collar to a second
bend, a first segment extending distally and radially inward from
the second bend to a third bend, a second segment extending
distally and radially inward from the third bend to a fourth bend,
and a third segment extending proximally and radially inward from
the fourth bend to the annular ring member; and [0061] attaching a
membrane over at least a portion of the plurality of struts such
that the plurality of anchors extends through the membrane.
[0062] FIG. 11 illustrates the example implant 200 having a
membrane 230 disposed over at least a portion of the support frame
210. While not explicitly illustrated, the implant 200 shown in
FIGS. 5-9 may include the membrane 230. In the interest of clarity,
the membrane 230 was not shown in FIGS. 5-9. In some embodiments,
at least some of the plurality of anchors 250 project through the
membrane 230. In some embodiments, the membrane 230 may be attached
to the support frame 210 at each anchor 250, for example, by
passing each anchor 250 through the membrane 230, such as through a
pore or aperture. In some embodiments, the membrane 230 may be
attached to the support frame 210 by other suitable attachment
means, such as but not limited to, adhesive(s), sutures or
thread(s), welding or soldering, or combinations thereof. In some
embodiments, the membrane 230 may be permeable or impermeable to
blood and/or other fluids, such as water. In some embodiments, the
membrane 230 may include a polymeric membrane, a metallic or
polymeric mesh, a porous filter-like material, or other suitable
construction. In some embodiments, the membrane 230 prevents
thrombi (i.e. blood clots, etc.) from passing through the membrane
230 and out of the left atrial appendage into the blood stream. In
some embodiments, the membrane 230 promotes endothelization after
implantation, thereby effectively removing the left atrial
appendage from the patient's circulatory system.
[0063] FIG. 12 illustrates a partial cross-sectional view of the
implant 200 disposed within an example left atrial appendage, such
as that shown in FIG. 2, in a deployed position. As can be seen in
FIG. 12, the support frame 210 may be compliant and substantially
conform to and/or be in sealing engagement with the shape and/or
geometry of the lateral wall of the left atrial appendage in the
deployed position. At its largest size, extent, or shape, the
implant 200 may expand to the fourth, unconstrained position in the
deployed position. In some embodiments, the implant 200 may expand
to a size, extent, or shape less than or different from the fourth,
unconstrained position in the deployed position, which may be
partially constrained, as determined by the surrounding tissue
and/or lateral wall of the left atrial appendage. Reducing the
thickness of the plurality of struts compared to the device shown
in FIG. 3 increases the flexibility and compliance of the support
frame 210 and/or the implant 200, thereby permitting the implant
200 to conform to the tissue around it, rather than forcing the
tissue to conform to the implant.
[0064] In some embodiments, the plurality of struts of the support
frame 210 and/or the plurality of anchors 250 may be formed of or
include a metallic material, a metallic alloy, a ceramic material,
a rigid or high performance polymer, a metallic-polymer composite,
combinations thereof, and the like. Some examples of some suitable
materials may include metallic materials and/or alloys such as
stainless steel (e.g., 303, 304v, or 316L stainless steel),
nickel-titanium alloy (e.g., nitinol, such as super elastic or
linear elastic nitinol), nickel-chromium alloy,
nickel-chromium-iron alloy, cobalt alloy, nickel, titanium,
platinum, or alternatively, a polymer material, such as a high
performance polymer, or other suitable materials, and the like. The
word nitinol was coined by a group of researchers at the United
States Naval Ordinance Laboratory (NOL) who were the first to
observe the shape memory behavior of this material. The word
nitinol is an acronym including the chemical symbol for nickel
(Ni), the chemical symbol for titanium (Ti), and an acronym
identifying the Naval Ordinance Laboratory (NOL).
[0065] In some embodiments, the plurality of struts of the support
frame 210 and/or the plurality of anchors 250 may be mixed with,
may be doped with, may be coated with, or may otherwise include a
radiopaque material. Radiopaque materials are understood to be
materials capable of producing a relatively bright image on a
fluoroscopy screen or another imaging technique such as X-ray
during a medical procedure. This relatively bright image aids the
user of device in determining its location. Suitable radiopaque
materials may include, but are not limited to, bismuth
subcarbonate, iodine, gold, platinum, palladium, tantalum, tungsten
or tungsten alloy, and the like.
[0066] In some embodiments, the membrane 230 may be formed of or
include a polymeric material, a metallic or metallic alloy
material, a metallic-polymer composite, combinations thereof, and
the like. In some embodiments, the membrane 230 is preferably
formed of polyethylene terephthalate (PET) such as DACRON.RTM., or
expanded polytetrafluoroethylene (ePTFE). Other examples of
suitable polymers may include polyurethane, a polyether-ester such
as ARNITEL.RTM. available from DSM Engineering Plastics, a
polyester such as HYTREL.RTM. available from DuPont, a linear low
density polyethylene such as REXELL.RTM., a polyamide such as
DURETHAN.RTM. available from Bayer or CRISTAMID.RTM. available from
Elf Atochem, an elastomeric polyamide, a block polyamide/ether, a
polyether block amide such as PEBA available under the trade name
PEBAX.RTM., silicones, polyethylene, Marlex high-density
polyethylene, polytetrafluoroethylene (PTFE), polyetheretherketone
(PEEK), polyimide (PI), and polyetherimide (PEI), a liquid crystal
polymer (LCP) alone or blended with other materials.
[0067] In some embodiments, the delivery catheter 290 and/or the
implant 200 may be made from, may be mixed with, may be coated
with, or may otherwise include a material that provides a smooth,
slick outer surface. In some embodiments, the delivery catheter 290
and/or the implant 200 may include or be coated with a lubricious
coating, a hydrophilic coating, a hydrophobic coating, a
drug-eluting material, an anti-thrombus coating, or other suitable
coating depending on the intended use or application.
[0068] It should be understood that although the above discussion
was focused on a medical device and methods of use within the
vascular system of a patient, other embodiments of medical devices
or methods in accordance with the disclosure can be adapted and
configured for use in other parts of the anatomy of a patient. For
example, devices and methods in accordance with the disclosure can
be adapted for use in the digestive or gastrointestinal tract, such
as in the mouth, throat, small and large intestine, colon, rectum,
and the like. For another example, devices and methods can be
adapted and configured for use within the respiratory tract, such
as in the mouth, nose, throat, bronchial passages, nasal passages,
lungs, and the like. Similarly, the apparatus and/or medical
devices described herein with respect to percutaneous deployment
may be used in other types of surgical procedures as appropriate.
For example, in some embodiments, the medical devices may be
deployed in a non-percutaneous procedure, such as an open heart
procedure. Devices and methods in accordance with the invention can
also be adapted and configured for other uses within the
anatomy.
[0069] It should be understood that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size, and arrangement of steps
without exceeding the scope of the invention. The invention's scope
is, of course, defined in the language in which the appended claims
are expressed.
* * * * *