U.S. patent application number 16/120112 was filed with the patent office on 2021-12-30 for sealing member for prosthetic heart valve.
The applicant listed for this patent is Edwards Lifesciences Corporation. Invention is credited to Lien Huong Thi Hoang, Russell T. Joseph, Hien Tran Ngo, Son V. Nguyen, Diana Nguyen-Thien-Nhon, Kevin D. Rupp, Dinesh L. Sirimanne, Vivian Tran.
Application Number | 20210401571 16/120112 |
Document ID | / |
Family ID | 1000006024422 |
Filed Date | 2021-12-30 |
United States Patent
Application |
20210401571 |
Kind Code |
A9 |
Hoang; Lien Huong Thi ; et
al. |
December 30, 2021 |
SEALING MEMBER FOR PROSTHETIC HEART VALVE
Abstract
A prosthetic heart valve includes an annular frame that has an
inflow end and an outflow end and is radially compressible and
expandable between a radially compressed configuration and a
radially expanded configuration. The prosthetic heart valve further
includes a leaflet structure positioned within the frame and
secured thereto, and an outer sealing member mounted outside of the
frame and adapted to seal against surrounding tissue when the
prosthetic heart valve is implanted within a native heart valve
annulus of a patient. The sealing member can include a mesh layer
and pile layer comprising a plurality of pile yarns extending
outwardly from the mesh layer.
Inventors: |
Hoang; Lien Huong Thi; (San
Juan Capistrano, CA) ; Nguyen; Son V.; (Irvine,
CA) ; Ngo; Hien Tran; (Irvine, CA) ; Tran;
Vivian; (Santa Ana, CA) ; Joseph; Russell T.;
(Las Flores, CA) ; Sirimanne; Dinesh L.; (Irvine,
CA) ; Rupp; Kevin D.; (Irvine, CA) ;
Nguyen-Thien-Nhon; Diana; (Irvine, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Edwards Lifesciences Corporation |
Irvine |
CA |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20190365530 A1 |
December 5, 2019 |
|
|
Family ID: |
1000006024422 |
Appl. No.: |
16/120112 |
Filed: |
August 31, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15991325 |
May 29, 2018 |
|
|
|
16120112 |
|
|
|
|
62513348 |
May 31, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2230/0069 20130101;
A61F 2/2418 20130101; A61F 2230/0006 20130101; A61F 2/2409
20130101; A61F 2230/0076 20130101 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A prosthetic heart valve, comprising: an annular frame
comprising an inflow end and an outflow end and being radially
compressible and expandable between a radially compressed
configuration and a radially expanded configuration; a leaflet
structure positioned within the frame and secured thereto; and an
outer sealing member mounted outside of the frame and adapted to
seal against surrounding tissue when the prosthetic heart valve is
implanted within a native heart valve annulus of a patient, the
sealing member comprising a mesh layer and pile layer comprising a
plurality of pile yarns extending outwardly from the mesh
layer.
2. The prosthetic heart valve of claim 1, wherein the mesh layer
comprises a knit or woven fabric.
3. The prosthetic heart valve of claim 1, wherein the pile yarns
are arranged to form a looped pile.
4. The prosthetic heart valve of claim 1, wherein the pile yarns
are cut to form a cut pile.
5. The prosthetic heart valve of claim 1, wherein the height of the
pile yarns varies along a height and/or a circumference of the
outer skirt.
6. The prosthetic heart valve of claim 5, wherein the pile yarns
comprise a first group of yarns along an upstream portion of the
outer skirt and a second group of yarns along a downstream portion
of the outer skirt, wherein the yarns of the first group have a
height that is less than a height of the yarns of the second
group.
7. The prosthetic heart valve of claim 5, wherein the pile yarns
comprise a first group of yarns along an upstream portion of the
outer skirt and a second group of yarns along a downstream portion
of the outer skirt, wherein the yarns of the first group have a
height that is greater than a height of the yarns of the second
group.
8. The prosthetic heart valve of claim 5, wherein the pile yarns
comprise a first group of yarns along an upstream portion of the
outer skirt, a second group of yarns along a downstream portion of
the outer skirt, and a third group of yarns between the first and
second group of yarns, wherein the yarns of the first and second
groups have a height that is greater than a height of the yarns of
the third group.
9. The prosthetic heart valve of claim 1, further comprising an
inner skirt mounted on an inner surface of the frame, the inner
skirt having an inflow end portion that is secured to an inflow end
portion of the outer sealing member.
10. The prosthetic heart valve of claim 9, wherein the inflow end
portion of the inner skirt is wrapped around an inflow end of the
frame and overlaps the inflow end portion of the outer sealing
member on the outside of the frame.
11. The prosthetic heart valve of claim 1, wherein the mesh layer
comprises a first mesh layer and the outer sealing member further
comprises a second mesh layer disposed radially outside of the pile
layer.
12. The prosthetic heart valve of claim 1, wherein the outer
sealing member is configured to stretch axially when the frame is
radially compressed to the radially compressed state.
13. The prosthetic heart valve of claim 1, wherein the mesh layer
comprises warp yarns and weft yarns woven with the warp yarns, and
the pile layer comprises the warp yarns or the weft yarns of the
mesh layer that are woven or knitted to form the pile yarns.
14. The prosthetic heart valve of claim 1, wherein the mesh layer
comprises a woven fabric layer and the pile layer comprises a
separate pile layer that is stitched to the woven fabric layer.
15. The prosthetic heart valve of claim 1, wherein the mesh layer
has a first height extending axially along the frame and the pile
layer comprises a second height extending axially along the frame,
wherein the first height is greater than the second height.
16. The prosthetic heart valve of claim 15, wherein the mesh layer
extends closer to the outflow end of the frame than the pile
layer.
17. A prosthetic heart valve, comprising: an annular frame
comprising an inflow end and an outflow end and being radially
compressible and expandable between a radially compressed
configuration and a radially expanded configuration; a leaflet
structure positioned within the frame and secured thereto; and an
outer sealing member mounted outside of the frame and adapted to
seal against surrounding tissue when the prosthetic heart valve is
implanted within a native heart valve annulus of a patient, the
sealing member comprising a fabric having a variable thickness.
18. The prosthetic heart valve of claim 17, wherein the thickness
of the fabric layer varies along a height and/or a circumference of
the outer sealing member.
19. The prosthetic heart valve of claim 17, wherein the fabric
comprises a plush fabric.
20. The prosthetic heart valve of claim 17, wherein the fabric
comprises a plurality of pile yarns and the height of the pile
yarns varies along a height and/or a circumference of the outer
skirt.
21. The prosthetic heart valve of claim 20, wherein the pile yarns
comprise a first group of yarns along an upstream portion of the
outer skirt and a second group of yarns along a downstream portion
of the outer skirt, wherein the yarns of the first group have a
height that is less than a height of the yarns of the second
group.
22. The prosthetic heart valve of claim 20, wherein the pile yarns
comprise a first group of yarns along an upstream portion of the
outer skirt and a second group of yarns along a downstream portion
of the outer skirt, wherein the yarns of the first group have a
height that is greater than a height of the yarns of the second
group.
23. The prosthetic heart valve of claim 20, wherein the pile yarns
comprise a first group of yarns along an upstream portion of the
outer skirt, a second group of yarns along a downstream portion of
the outer skirt, and a third group of yarns between the first and
second group of yarns, wherein the yarns of the first and second
groups have a height that is greater than a height of the yarns of
the third group.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 15/991,325 filed on May 29, 2018, which claims
the benefit of U.S. Patent Application No. 62/513,348, filed on May
31, 2017. The entire contents of the foregoing applications are
incorporated herein by reference.
FIELD
[0002] The present disclosure relates to implantable, expandable
prosthetic devices and to methods and apparatuses for such
prosthetic devices.
BACKGROUND
[0003] The human heart can suffer from various valvular diseases.
These valvular diseases can result in significant malfunctioning of
the heart and ultimately require replacement of the native valve
with an artificial valve. There are a number of known artificial
valves and a number of known methods of implanting these artificial
valves in humans. Because of the drawbacks associated with
conventional open-heart surgery, percutaneous and
minimally-invasive surgical approaches are garnering intense
attention. In one technique, a prosthetic valve is configured to be
implanted in a much less invasive procedure by way of
catheterization. For example, collapsible transcatheter prosthetic
heart valves can be crimped to a compressed state and
percutaneously introduced in the compressed state on a catheter and
expanded to a functional size at the desired position by balloon
inflation or by utilization of a self-expanding frame or stent.
[0004] A prosthetic valve for use in such a procedure can include a
radially collapsible and expandable frame to which leaflets of the
prosthetic valve can be coupled. For example, U.S. Pat. Nos.
6,730,118, 7,393,360, 7,510,575, and 7,993,394, which are
incorporated herein by reference, describe exemplary collapsible
transcatheter heart valves (THVs).
[0005] A challenge in catheter-implanted prosthetic valves is the
process of crimping such a prosthetic valve to a profile suitable
for percutaneous delivery to a subject. Another challenge is the
control of paravalvular leakage around the valve, which can occur
for a period of time following initial implantation.
[0006] Paravalvular leakage has been a known problem since the
first replacement valves were introduced. The earliest prosthetic
heart valves, those that were implanted surgically, included a
circumferential sewing ring that was adapted to extend into spaces
in the tissue surrounding the implanted prosthesis to prevent
paravalvular leaking. For example, U.S. Pat. No. 3,365,728
describes a prosthetic heart valve for surgical implantation that
includes a rubber "cushion ring" that conforms to irregularities of
the tissue to form an effective seal between the valve and the
surrounding tissue. From there, vascular stents or stent grafts
were developed that could be implanted by non-surgical
catheterization techniques. These stents included a fabric covering
that allowed the stent to be used to isolate and reinforce the wall
of a blood vessel from the lumen of the vessel. These fabric
coverings served essentially the same purpose on stents as did the
sealing rings on surgical heart valves--they reduced the risk of
blood leaking between the prosthesis and the surrounding tissue.
Multiple graft designs were developed that further enhanced the
external seal to prevent blood from flowing between the graft and
surrounding cardiovascular tissue. For example, U.S. Pat. No.
6,015,431 to Thornton discloses a seal secured to the outer surface
of a stent that is adapted to occlude leakage flow externally
around the stent wall between the outer surface and the endolumenal
wall when the stent is deployed, by conforming to the irregular
surface of the surrounding tissue. U.S. Patent Publication
2003/0236567 to Elliot similarly discloses a tubular prosthesis
having a stent and one or more fabric "skirts" to seal against
endoleaks. U.S. Patent Publication 2004/0082989 to Cook et al. also
recognized the potential for endoleaks, and describes a stent graft
having a cuff portion that has an external sealing zone that
extends around the body of the stent to prevent leakage. The cuff
portion could be folded over to create a pocket that collects any
blood passing around the leading edge of the graft to prevent an
endoleak.
[0007] Building on this technology, in the late 1980's, the first
permanent bioprosthetic heart valve was implanted using
transcatheter techniques. U.S. Pat. No. 5,411,552 to Andersen
describes a THV comprising a valve mounted within a collapsible and
expandable stent structure. Certain embodiments have additional
graft material used along the external and internal surface of the
THV. As with stent grafts, the covers proposed to be used with THVs
were designed to conform to the surface of the surrounding tissue
to prevent paravalvular leaks.
[0008] Like with stents, "cuffs" or other outer seals were used on
THVs. U.S. Pat. No. 5,855,601 to Bessler describes a self-expanding
THV having a cuff portion extending along the outside of the stent.
Upon collapse of the stent for delivery, the outer seal collapses
to form pleats, then expands with the stent to provide a seal
between the THV and the surrounding tissue.
[0009] Thereafter, a different THV design was described by Pavcnik
in U.S. Patent Application Publication 2001/0039450. The enhanced
sealing structure of Pavcnik is in the form of corner "flaps" or
"pockets" secured to the stent at the edges of each "flap" or
"pocket" and positioned at discrete locations around the
prosthesis. The corner flap was designed to catch retrograde blood
flow to provide a better seal between the THV and the vessel wall,
as well as to provide an improved substrate for ingrowth of native
tissue.
[0010] Thus, fabric and other materials used to cover and seal both
internal and external surfaces of THVs and other endovascular
prostheses such as stents and stent grafts are well known. These
covers can be made with low-porosity woven fabric materials, as
described, for example, by U.S. Pat. No. 5,957,949 to Leonhardt et
al., which describes a valve stent having an outer cover that can
conform to the living tissue surrounding it upon implantation to
help prevent blood leakage.
[0011] Several more recent THV designs include a THV with an outer
covering. U.S. Pat. No. 7,510,575 to Spenser discloses a THV having
a cuff portion wrapped around the outer surface of the support
stent at the inlet. The cuff portion is rolled up over the edge of
the frame so as to provide a "sleeve-like" portion at the inlet to
form a cuff over the inlet that helps prevent blood leakage. U.S.
Pat. No. 8,002,825 to Letac and Cribier describes an internal cover
that extends from the base of the valve to the lower end of the
stent and then up the external wall of the stent so as to form an
external cover. The single-piece cover could be made with any of
the materials disclosed for making the valve structure, which
include fabric (e.g., Dacron), biological material (e.g.,
pericardium), or other synthetic materials (e.g.,
polyethylene).
[0012] While covers used on the external surface of an endovascular
prosthesis to prevent paravalvular leaking are well known, there
remains a need for improved coverings that provide enhanced sealing
while still providing a small profile suitable for percutaneous
delivery to a patient.
SUMMARY
[0013] Embodiments of a radially collapsible and expandable
prosthetic valve are disclosed herein that include an improved
outer skirt for reducing perivalvular leakage, as well as related
methods and apparatuses including such prosthetic valves. In
several embodiments, the disclosed prosthetic valves are configured
as replacement heart valves for implantation into a subject.
[0014] In one representative embodiment, a prosthetic heart valve
comprises an annular frame that comprises an inflow end and an
outflow end and is radially compressible and expandable between a
radially compressed configuration and a radially expanded
configuration. The prosthetic heart valve further includes a
leaflet structure positioned within the frame and secured thereto,
and an outer sealing member mounted outside of the frame and
adapted to seal against surrounding tissue when the prosthetic
heart valve is implanted within a native heart valve annulus of a
patient. The sealing member can comprise a mesh layer and pile
layer comprising a plurality of pile yarns extending outwardly from
the mesh layer.
[0015] In some embodiments, the mesh layer comprises a knit or
woven fabric.
[0016] In some embodiments, the pile yarns are arranged to form a
looped pile.
[0017] In some embodiments, the pile yarns are cut to form a cut
pile.
[0018] In some embodiments, the height of the pile yarns varies
along a height and/or a circumference of the outer skirt.
[0019] In some embodiments, the pile yarns comprise a first group
of yarns along an upstream portion of the outer skirt and a second
group of yarns along a downstream portion of the outer skirt,
wherein the yarns of the first group have a height that is less
than a height of the yarns of the second group.
[0020] In some embodiments, the pile yarns comprise a first group
of yarns along an upstream portion of the outer skirt and a second
group of yarns along a downstream portion of the outer skirt,
wherein the yarns of the first group have a height that is greater
than a height of the yarns of the second group.
[0021] In some embodiments, the pile yarns comprise a first group
of yarns along an upstream portion of the outer skirt, a second
group of yarns along a downstream portion of the outer skirt, and a
third group of yarns between the first and second group of yarns,
wherein the yarns of the first and second groups have a height that
is greater than a height of the yarns of the third group.
[0022] In some embodiments, the prosthetic heart valve further
comprises an inner skirt mounted on an inner surface of the frame,
the inner skirt having an inflow end portion that is secured to an
inflow end portion of the outer sealing member.
[0023] In some embodiments, the inflow end portion of the inner
skirt is wrapped around an inflow end of the frame and overlaps the
inflow end portion of the outer sealing member on the outside of
the frame.
[0024] In some embodiments, the mesh layer comprises a first mesh
layer and the outer sealing member further comprises a second mesh
layer disposed radially outside of the pile layer.
[0025] In some embodiments, the outer sealing member is configured
to stretch axially when the frame is radially compressed to the
radially compressed state.
[0026] In some embodiments, the mesh layer comprises warp yarns and
weft yarns woven with the warp yarns, and the pile layer comprises
the warp yarns or the weft yarns of the mesh layer that are woven
or knitted to form the pile yarns.
[0027] In some embodiments, the mesh layer comprises a woven fabric
layer and the pile layer comprises a separate pile layer that is
stitched to the woven fabric layer.
[0028] In some embodiment, the mesh layer has a first height
extending axially along the frame and the pile layer comprises a
second height extending axially along the frame, wherein the first
height is greater than the second height.
[0029] In some embodiment, the mesh layer extends closer to the
outflow end of the frame than the pile layer.
[0030] In another representative embodiment, a prosthetic heart
valve comprises an annular frame that comprises an inflow end and
an outflow end and is radially compressible and expandable between
a radially compressed configuration and a radially expanded
configuration. The prosthetic heart valve further comprises a
leaflet structure positioned within the frame and secured thereto,
an outer sealing member mounted outside of the frame and adapted to
seal against surrounding tissue when the prosthetic heart valve is
implanted within a native heart valve annulus of a patient. The
sealing member can comprise a fabric having a variable
thickness.
[0031] In some embodiments, the thickness of the fabric layer
varies along a height and/or a circumference of the outer sealing
member.
[0032] In some embodiments, the fabric comprises a plush
fabric.
[0033] In some embodiments, the fabric comprises a plurality of
pile yarns and the height of the pile yarns varies along a height
and/or a circumference of the outer skirt.
[0034] In some embodiments, the pile yarns comprise a first group
of yarns along an upstream portion of the outer skirt and a second
group of yarns along a downstream portion of the outer skirt,
wherein the yarns of the first group have a height that is less
than a height of the yarns of the second group.
[0035] In some embodiments, the pile yarns comprise a first group
of yarns along an upstream portion of the outer skirt and a second
group of yarns along a downstream portion of the outer skirt,
wherein the yarns of the first group have a height that is greater
than a height of the yarns of the second group.
[0036] In some embodiments, the pile yarns comprise a first group
of yarns along an upstream portion of the outer skirt, a second
group of yarns along a downstream portion of the outer skirt, and a
third group of yarns between the first and second group of yarns,
wherein the yarns of the first and second groups have a height that
is greater than a height of the yarns of the third group.
[0037] In another representative embodiment, a prosthetic heart
valve comprises an annular frame that comprises an inflow end and
an outflow end and is radially compressible and expandable between
a radially compressed configuration and a radially expanded
configuration. The prosthetic heart valve further comprises a
leaflet structure positioned within the frame and secured thereto,
an outer sealing member mounted outside of the frame and adapted to
seal against surrounding tissue when the prosthetic heart valve is
implanted within a native heart valve annulus of a patient. The
sealing member can comprise a pile fabric comprising a plurality of
pile yarns, wherein the density of the pile yarns varies in an
axial direction and/or a circumferential direction along the
sealing member.
[0038] In some embodiments, the pile yarns are arranged in
circumferentially extending rows of pile yarns and the density of
the pile yarns varies from row to row.
[0039] In some embodiments, the pile yarns are arranged in axially
extending rows pile yarns and the density of the pile yarns varies
from row to row.
[0040] In some embodiments, the sealing member comprises a mesh
layer and a pile layer comprising the pile yarns. In some
embodiments, the weave density of the mesh layer varies in an axial
direction and/or a circumferential direction along the sealing
member. In some embodiments, the mesh layer comprises one or more
rows of higher-density mesh portions and one or more rows of
lower-density mesh portions. The one or more rows of higher-density
mesh portions and the one or more rows of lower-density mesh
portions can be circumferentially extending rows and/or axially
extending rows.
[0041] In another representative embodiment, a prosthetic heart
valve comprises an annular frame that comprises an inflow end and
an outflow end and is radially compressible and expandable between
a radially compressed configuration and a radially expanded
configuration. The prosthetic heart valve further comprises a
leaflet structure positioned within the frame and secured thereto,
an outer sealing member mounted outside of the frame and adapted to
seal against surrounding tissue when the prosthetic heart valve is
implanted within a native heart valve annulus of a patient. The
sealing member comprises a textile formed from a plurality fibers
arranged in a plurality of axially extending rows of higher stitch
density interspersed between a plurality of axially extending rows
of lower stitch density. The sealing member is configured to
stretch axially between a first, substantially relaxed, axially
foreshortened configuration when the frame is the radially expanded
configuration and a second, axially elongated configuration when
the frame is in the radially compressed configuration.
[0042] In some embodiments, each of the rows of higher stitch
density can extend in an undulating pattern when the sealing member
is in the axially foreshortened configuration. When the sealing
member is in the axially elongated configuration, the rows of
higher stitch density move from the undulating pattern toward a
straightened pattern.
[0043] In another representative embodiment, a prosthetic heart
valve comprises an annular frame that comprises an inflow end and
an outflow end and is radially compressible and expandable between
a radially compressed configuration and a radially expanded
configuration. The prosthetic heart valve further comprises a
leaflet structure positioned within the frame and secured thereto,
an outer sealing member mounted outside of the frame and adapted to
seal against surrounding tissue when the prosthetic heart valve is
implanted within a native heart valve annulus of a patient. The
sealing member comprises a fabric comprising a plurality of axially
extending filaments and a plurality of circumferentially extending
filaments. The sealing member is configured to stretch axially when
the frame is radially compressed from the radially expanded
configuration to the radially compressed configuration. The axially
extending filaments move from a deformed or twisted state when the
frame is in the radially expanded configuration to a less deformed
or less twisted state when the frame is in the radially compressed
configuration.
[0044] In some embodiments, the axially extending filaments are
heat set in the deformed or twisted state.
[0045] In some embodiments, the thickness of the sealing member
decreases when the axially extending filaments move from the
deformed or twisted state to the less deformed or twisted
state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] FIG. 1 is a perspective view of a prosthetic heart valve,
according to one embodiment.
[0047] FIG. 2 is an enlarged, perspective view of the inflow end
portion of the prosthetic heart valve of FIG. 1.
[0048] FIG. 3 is a cross-sectional view of the prosthetic heart
valve of FIG. 1, showing the attachment of the outer skirt to the
inner skirt and the frame.
[0049] FIGS. 4-10 show an exemplary frame of the prosthetic heart
valve of FIG. 1.
[0050] FIGS. 11-12 show an exemplary inner skirt of the prosthetic
heart valve of FIG. 1.
[0051] FIGS. 13-15 show the assembly of the inner skirt of FIG. 11
with the frame of FIG. 4.
[0052] FIGS. 16-17 show the assembly of an exemplary leaflet
structure.
[0053] FIG. 18 shows the assembly of commissure portions of the
leaflet structure with window frame portions of the frame.
[0054] FIGS. 19-20 show the assembly of the leaflet structure with
the inner skirt along a lower edge of the leaflets.
[0055] FIGS. 21-23 are different views of an exemplary outer skirt
of the prosthetic heart valve of FIG. 1.
[0056] FIG. 24-26 are cross-sectional views similar to FIG. 3 but
showing different embodiments of the outer skirt.
[0057] FIGS. 27-28 show an alternative way of securing an outer
skirt to an inner skirt and/or the frame of a prosthetic heart
valve.
[0058] FIGS. 29-32 show another way of securing an outer skirt to
an inner skirt and/or the frame of a prosthetic heart valve.
[0059] FIGS. 33-35 show another embodiment of an outer sealing
member for a prosthetic heart valve.
[0060] FIG. 36 shows another embodiment of an outer sealing member,
shown mounted on the frame of a prosthetic heart valve.
[0061] FIG. 37 is a flattened view of a woven mesh layer of the
sealing member of FIG. 36.
[0062] FIG. 38 is a flattened view of a pile layer of the sealing
member of FIG. 36.
[0063] FIG. 39 is a flattened view of the outer surface of an outer
sealing member for a prosthetic heart valve, according to another
embodiment.
[0064] FIG. 39A is a magnified view of a portion of the sealing
member of FIG. 39.
[0065] FIG. 40 is a flattened view of the inner surface of the
sealing member of FIG. 39.
[0066] FIG. 40A is a magnified view of a portion of the sealing
member of FIG. 40.
[0067] FIG. 41 is flattened view of an outer sealing member for a
prosthetic heart valve shown in a relaxed state when the prosthetic
heart valve is radially expanded to its functional size, according
to another embodiment.
[0068] FIG. 42 is a flattened view of the outer sealing member of
FIG. 41 shown in an axially elongated, tensioned state when the
prosthetic heart valve is in a radially compressed state for
delivery.
[0069] FIG. 43A is a magnified view of a portion of another
embodiment of an outer sealing member for a prosthetic heart valve,
wherein the sealing member is shown in a relaxed state when the
prosthetic heart valve is radially expanded to its functional
size.
[0070] FIG. 43B is a magnified view of the sealing member of FIG.
43A shown in an axially elongated, tensioned state when the
prosthetic heart valve is in a radially compressed state for
delivery.
[0071] FIG. 44A is a cross-sectional view of the fabric of the
sealing member of FIG. 43A in a relaxed state.
[0072] FIG. 44B is a cross-sectional view of the fabric of the
sealing member of FIG. 43B in a tensioned state.
DETAILED DESCRIPTION
[0073] FIG. 1 shows a prosthetic heart valve 10, according to one
embodiment. The illustrated prosthetic valve is adapted to be
implanted in the native aortic annulus, although in other
embodiments it can be adapted to be implanted in the other native
annuluses of the heart (e.g., the pulmonary, mitral, and tricuspid
valves). The prosthetic valve can also be adapted to be implanted
in other tubular organs or passageways in the body. The prosthetic
valve 10 can have four main components: a stent or frame 12, a
valvular structure 14, an inner skirt 16, and a perivalvular outer
sealing member or outer skirt 18. The prosthetic valve 10 can have
an inflow end portion 15, an intermediate portion 17, and an
outflow end portion 19.
[0074] The valvular structure 14 can comprise three leaflets 40
(FIG. 17), collectively forming a leaflet structure, which can be
arranged to collapse in a tricuspid arrangement. The lower edge of
leaflet structure 14 desirably has an undulating, curved scalloped
shape (suture line 154 shown in FIG. 20 tracks the scalloped shape
of the leaflet structure). By forming the leaflets with this
scalloped geometry, stresses on the leaflets are reduced, which in
turn improves durability of the prosthetic valve. Moreover, by
virtue of the scalloped shape, folds and ripples at the belly of
each leaflet (the central region of each leaflet), which can cause
early calcification in those areas, can be eliminated or at least
minimized. The scalloped geometry also reduces the amount of tissue
material used to form leaflet structure, thereby allowing a
smaller, more even crimped profile at the inflow end of the
prosthetic valve. The leaflets 40 can be formed of pericardial
tissue (e.g., bovine pericardial tissue), biocompatible synthetic
materials, or various other suitable natural or synthetic materials
as known in the art and described in U.S. Pat. No. 6,730,118, which
is incorporated by reference herein.
[0075] The bare frame 12 is shown in FIG. 4. The frame 12 can be
formed with a plurality of circumferentially spaced slots, or
commissure windows, 20 (three in the illustrated embodiment) that
are adapted to mount the commissures of the valvular structure 14
to the frame, as described in greater detail below. The frame 12
can be made of any of various suitable plastically-expandable
materials (e.g., stainless steel, etc.) or self-expanding materials
(e.g., nickel titanium alloy (NiTi), such as nitinol) as known in
the art. When constructed of a plastically-expandable material, the
frame 12 (and thus the prosthetic valve 10) can be crimped to a
radially collapsed configuration on a delivery catheter and then
expanded inside a patient by an inflatable balloon or equivalent
expansion mechanism. When constructed of a self-expandable
material, the frame 12 (and thus the prosthetic valve 10) can be
crimped to a radially collapsed configuration and restrained in the
collapsed configuration by insertion into a sheath or equivalent
mechanism of a delivery catheter. Once inside the body, the
prosthetic valve can be advanced from the delivery sheath, which
allows the prosthetic valve to expand to its functional size.
[0076] Suitable plastically-expandable materials that can be used
to form the frame 12 include, without limitation, stainless steel,
a biocompatible, high-strength alloys (e.g., a cobalt-chromium or a
nickel-cobalt-chromium alloys), polymers, or combinations thereof.
In particular embodiments, frame 12 is made of a
nickel-cobalt-chromium-molybdenum alloy, such as MP35N.RTM. alloy
(SPS Technologies, Jenkintown, Pa.), which is equivalent to UNS
R30035 alloy (covered by ASTM F562-02). MP35N.RTM. alloy/UNS R30035
alloy comprises 35% nickel, 35% cobalt, 20% chromium, and 10%
molybdenum, by weight. It has been found that the use of MP35N.RTM.
alloy to form frame 12 provides superior structural results over
stainless steel. In particular, when MP35N.RTM. alloy is used as
the frame material, less material is needed to achieve the same or
better performance in radial and crush force resistance, fatigue
resistances, and corrosion resistance. Moreover, since less
material is required, the crimped profile of the frame can be
reduced, thereby providing a lower profile prosthetic valve
assembly for percutaneous delivery to the treatment location in the
body.
[0077] Referring to FIGS. 4 and 5, the frame 12 in the illustrated
embodiment comprises a first, lower row I of angled struts 22
arranged end-to-end and extending circumferentially at the inflow
end of the frame; a second row II of circumferentially extending,
angled struts 24; a third row III of circumferentially extending,
angled struts 26; a fourth row IV of circumferentially extending,
angled struts 28; and a fifth row V of circumferentially extending,
angled struts 32 at the outflow end of the frame. A plurality of
substantially straight axially extending struts 34 can be used to
interconnect the struts 22 of the first row I with the struts 24 of
the second row II. The fifth row V of angled struts 32 are
connected to the fourth row IV of angled struts 28 by a plurality
of axially extending window frame portions 30 (which define the
commissure windows 20) and a plurality of axially extending struts
31. Each axial strut 31 and each frame portion 30 extends from a
location defined by the convergence of the lower ends of two angled
struts 32 to another location defined by the convergence of the
upper ends of two angled struts 28. FIGS. 6, 7, 8, 9, and 10 are
enlarged views of the portions of the frame 12 identified by
letters A, B, C, D, and E, respectively, in FIG. 5.
[0078] Each commissure window frame portion 30 mounts a respective
commissure of the leaflet structure 14. As can be seen each frame
portion 30 is secured at its upper and lower ends to the adjacent
rows of struts to provide a robust configuration that enhances
fatigue resistance under cyclic loading of the prosthetic valve
compared to known, cantilevered struts for supporting the
commissures of the leaflet structure. This configuration enables a
reduction in the frame wall thickness to achieve a smaller crimped
diameter of the prosthetic valve. In particular embodiments, the
thickness T of the frame 12 (FIG. 4) measured between the inner
diameter and outer diameter is about 0.48 mm or less.
[0079] The struts and frame portions of the frame collectively
define a plurality of open cells of the frame. At the inflow end of
the frame 12, struts 22, struts 24, and struts 34 define a lower
row of cells defining openings 36. The second, third, and fourth
rows of struts 24, 26, and 28 define two intermediate rows of cells
defining openings 38. The fourth and fifth rows of struts 28 and
32, along with frame portions 30 and struts 31, define an upper row
of cells defining openings 40. The openings 41 are relatively large
and are sized to allow portions of the leaflet structure 14 to
protrude, or bulge, into and/or through the openings 40 when the
frame 12 is crimped in order to minimize the crimping profile.
[0080] As best shown in FIG. 7, the lower end of the strut 31 is
connected to two struts 28 at a node or junction 44, and the upper
end of the strut 31 is connected to two struts 32 at a node or
junction 46. The strut 31 can have a thickness S1 that is less than
the thicknesses S2 of the junctions 44, 46. The junctions 44, 46,
along with junctions 64, prevent full closure of openings 40. The
geometry of the struts 31, and junctions 44, 46, and 64 assists in
creating enough space in openings 41 in the collapsed configuration
to allow portions of the prosthetic leaflets to protrude or bulge
outwardly through openings. This allows the prosthetic valve to be
crimped to a relatively smaller diameter than if all of the leaflet
material were constrained within the crimped frame.
[0081] The frame 12 is configured to reduce, to prevent, or to
minimize possible over-expansion of the prosthetic valve at a
predetermined balloon pressure, especially at the outflow end
portion of the frame, which supports the leaflet structure 14. In
one aspect, the frame is configured to have relatively larger
angles 42a, 42b, 42c, 42d, 42e between struts, as shown in FIG. 5.
The larger the angle, the greater the force required to open
(expand) the frame. As such, the angles between the struts of the
frame can be selected to limit radial expansion of the frame at a
given opening pressure (e.g., inflation pressure of the balloon).
In particular embodiments, these angles are at least 110 degrees or
greater when the frame is expanded to its functional size, and even
more particularly these angles are up to about 120 degrees when the
frame is expanded to its functional size.
[0082] In addition, the inflow and outflow ends of a frame
generally tend to over-expand more so than the middle portion of
the frame due to the "dog-boning" effect of the balloon used to
expand the prosthetic valve. To protect against over-expansion of
the leaflet structure 14, the leaflet structure desirably is
secured to the frame 12 below the upper row of struts 32, as best
shown in FIG. 1. Thus, in the event that the outflow end of the
frame is over-expanded, the leaflet structure is positioned at a
level below where over-expansion is likely to occur, thereby
protecting the leaflet structure from over-expansion.
[0083] In a known prosthetic valve construction, portions of the
leaflets can protrude longitudinally beyond the outflow end of the
frame when the prosthetic valve is crimped if the leaflets are
mounted too close to the distal end of the frame. If the delivery
catheter on which the crimped prosthetic valve is mounted includes
a pushing mechanism or stop member that pushes against or abuts the
outflow end of the prosthetic valve (for example, to maintain the
position of the crimped prosthetic valve on the delivery catheter),
the pushing member or stop member can damage the portions of the
exposed leaflets that extend beyond the outflow end of the frame.
Another benefit of mounting the leaflets at a location spaced away
from the outflow end of the frame is that when the prosthetic valve
is crimped on a delivery catheter, the outflow end of the frame 12
rather than the leaflets 40 is the proximal-most component of the
prosthetic valve 10. As such, if the delivery catheter includes a
pushing mechanism or stop member that pushes against or abuts the
outflow end of the prosthetic valve, the pushing mechanism or stop
member contacts the outflow end of the frame, and not leaflets 40,
so as to avoid damage to the leaflets.
[0084] Also, as can be seen in FIG. 5, the openings 36 of the
lowermost row of openings in the frame are relatively larger than
the openings 38 of the two intermediate rows of openings. This
allows the frame, when crimped, to assume an overall tapered shape
that tapers from a maximum diameter at the outflow end of the
prosthetic valve to a minimum diameter at the inflow end of the
prosthetic valve. When crimped, the frame 12 has a reduced diameter
region extending along a portion of the frame adjacent the inflow
end of the frame that generally corresponds to the region of the
frame covered by the outer skirt 18. In some embodiments, the
reduced diameter region is reduced compared to the diameter of the
upper portion of the frame (which is not covered by the outer
skirt) such that the outer skirt 18 does not increase the overall
crimp profile of the prosthetic valve. When the prosthetic valve is
deployed, the frame can expand to the generally cylindrical shape
shown in FIG. 4. In one example, the frame of a 26-mm prosthetic
valve, when crimped, had a first diameter of 14 French at the
outflow end of the prosthetic valve and a second diameter of 12
French at the inflow end of the prosthetic valve.
[0085] The main functions of the inner skirt 16 are to assist in
securing the valvular structure 14 to the frame 12 and to assist in
forming a good seal between the prosthetic valve and the native
annulus by blocking the flow of blood through the open cells of the
frame 12 below the lower edge of the leaflets. The inner skirt 16
desirably comprises a tough, tear resistant material such as
polyethylene terephthalate (PET), although various other synthetic
materials or natural materials (e.g., pericardial tissue) can be
used. The thickness of the skirt desirably is less than about 0.15
mm (about 6 mil), and desirably less than about 0.1 mm (about 4
mil), and even more desirably about 0.05 mm (about 2 mil). In
particular embodiments, the skirt 16 can have a variable thickness,
for example, the skirt can be thicker at at least one of its edges
than at its center. In one implementation, the skirt 16 can
comprise a PET skirt having a thickness of about 0.07 mm at its
edges and about 0.06 mm at its center. The thinner skirt can
provide for better crimping performances while still providing good
perivalvular sealing.
[0086] The inner skirt 16 can be secured to the inside of frame 12
via sutures 70, as shown in FIG. 20. Valvular structure 14 can be
attached to the skirt via one or more reinforcing strips 72 (which
collectively can form a sleeve), for example thin, PET reinforcing
strips, discussed below, which enables a secure suturing and
protects the pericardial tissue of the leaflet structure from
tears. Valvular structure 14 can be sandwiched between skirt 16 and
the thin PET strips 72 as shown in FIG. 19. Sutures 154, which
secure the PET strip and the leaflet structure 14 to skirt 16, can
be any suitable suture, such as Ethibond Excel.RTM. PET suture
(Johnson & Johnson, New Brunswick, N.J.). Sutures 154 desirably
track the curvature of the bottom edge of leaflet structure 14, as
described in more detail below.
[0087] Known fabric skirts may comprise a weave of warp and weft
fibers that extend perpendicularly to each other and with one set
of the fibers extending longitudinally between the upper and lower
edges of the skirt. When the metal frame to which the fabric skirt
is secured is radially compressed, the overall axial length of the
frame increases. Unfortunately, a fabric skirt with limited
elasticity cannot elongate along with the frame and therefore tends
to deform the struts of the frame and to prevent uniform
crimping.
[0088] Referring to FIG. 12, in contrast to known fabric skirts,
the skirt 16 desirably is woven from a first set of fibers, or
yarns or strands, 78 and a second set of fibers, or yarns or
strands, 80, both of which are non-perpendicular to the upper edge
82 and the lower edge 84 of the skirt. In particular embodiments,
the first set of fibers 78 and the second set of fibers 80 extend
at angles of about 45 degrees relative to the upper and lower edges
82, 84. Alternatively, the first set of fibers 78 and the second
set of fibers 80 extend at angles other than about 45 degrees
relative to the upper and lower edges 82, 84, e.g., at angles of 15
and 75 degrees, respectively, or 30 and 60 degrees, respectively,
relative to the upper and lower edges 82, 84. For example, the
skirt 16 can be formed by weaving the fibers at 45 degree angles
relative to the upper and lower edges of the fabric. Alternatively,
the skirt 16 can be diagonally cut (cut on a bias) from a
vertically woven fabric (where the fibers extend perpendicularly to
the edges of the material) such that the fibers extend at 45 degree
angles relative to the cut upper and lower edges of the skirt. As
further shown in FIG. 12, the opposing short edges 86, 88 of the
skirt desirably are non-perpendicular to the upper and lower edges
82, 84. For example, the short edges 86, 88 desirably extend at
angles of about 45 degrees relative to the upper and lower edges
and therefore are aligned with the first set of fibers 78.
Therefore the overall general shape of the skirt is that of a
rhomboid or parallelogram.
[0089] FIGS. 13 and 14 show the inner skirt 16 after opposing short
edge portions 90, 92 have been sewn together to form the annular
shape of the skirt. As shown, the edge portion 90 can be placed in
an overlapping relationship relative to the opposite edge portion
92, and the two edge portions can be sewn together with a
diagonally extending suture line 94 that is parallel to short edges
86, 88. The upper edge portion of the inner skirt 16 can be formed
with a plurality of projections 96 that define an undulating shape
that generally follows the shape or contour of the fourth row of
struts 28 immediately adjacent the lower ends of axial struts 31.
In this manner, as best shown in FIG. 15, the upper edge of the
inner skirt 16 can be tightly secured to struts 28 with sutures 70.
The inner skirt 16 can also be formed with slits 98 to facilitate
attachment of the skirt to the frame. Slits 98 are dimensioned so
as to allow an upper edge portion of the inner skirt 16 to be
partially wrapped around struts 28 and to reduce stresses in the
skirt during the attachment procedure. For example, in the
illustrated embodiment, the inner skirt 16 is placed on the inside
of frame 12 and an upper edge portion of the skirt is wrapped
around the upper surfaces of struts 28 and secured in place with
sutures 70. Wrapping the upper edge portion of the inner skirt 16
around struts 28 in this manner provides for a stronger and more
durable attachment of the skirt to the frame. The inner skirt 16
can also be secured to the first, second, and/or third rows of
struts 22, 24, and 26, respectively, with sutures 70.
[0090] Due to the angled orientation of the fibers relative to the
upper and lower edges, the skirt can undergo greater elongation in
the axial direction (i.e., in a direction from the upper edge 82 to
the lower edge 84). Thus, when the metal frame 12 is crimped, the
inner skirt 16 can elongate in the axial direction along with the
frame and therefore provide a more uniform and predictable crimping
profile. Each cell of the metal frame in the illustrated embodiment
includes at least four angled struts that rotate towards the axial
direction on crimping (e.g., the angled struts become more aligned
with the length of the frame). The angled struts of each cell
function as a mechanism for rotating the fibers of the skirt in the
same direction of the struts, allowing the skirt to elongate along
the length of the struts. This allows for greater elongation of the
skirt and avoids undesirable deformation of the struts when the
prosthetic valve is crimped.
[0091] In addition, the spacing between the woven fibers or yarns
can be increased to facilitate elongation of the skirt in the axial
direction. For example, for a PET inner skirt 16 formed from
20-denier yarn, the yarn density can be about 15% to about 30%
lower than in a typical PET skirt. In some examples, the yarn
spacing of the inner skirt 16 can be from about 60 yarns per cm
(about 155 yarns per inch) to about 70 yarns per cm (about 180
yarns per inch), such as about 63 yarns per cm (about 160 yarns per
inch), whereas in a typical PET skirt the yarn spacing can be from
about 85 yarns per cm (about 217 yarns per inch) to about 97 yarns
per cm (about 247 yarns per inch). The oblique edges 86, 88 promote
a uniform and even distribution of the fabric material along inner
circumference of the frame during crimping so as to reduce or
minimize bunching of the fabric to facilitate uniform crimping to
the smallest possible diameter. Additionally, cutting diagonal
sutures in a vertical manner may leave loose fringes along the cut
edges. The oblique edges 86, 88 help minimize this from occurring.
Compared to the construction of a typical skirt (fibers running
perpendicularly to the upper and lower edges of the skirt), the
construction of the inner skirt 16 avoids undesirable deformation
of the frame struts and provides more uniform crimping of the
frame.
[0092] In alternative embodiments, the skirt can be formed from
woven elastic fibers that can stretch in the axial direction during
crimping of the prosthetic valve. The warp and weft fibers can run
perpendicularly and parallel to the upper and lower edges of the
skirt, or alternatively, they can extend at angles between 0 and 90
degrees relative to the upper and lower edges of the skirt, as
described above.
[0093] The inner skirt 16 can be sutured to the frame 12 at
locations away from the suture line 154 so that the skirt can be
more pliable in that area. This configuration can avoid stress
concentrations at the suture line 154, which attaches the lower
edges of the leaflets to the inner skirt 16.
[0094] As noted above, the leaflet structure 14 in the illustrated
embodiment includes three flexible leaflets 40 (although a greater
or a smaller number of leaflets can be used). Additional
information regarding the leaflets, as well as additional
information regarding skirt material, can be found, for example, in
U.S. patent application Ser. No. 14/704,861, filed May 5, 2015,
which is incorporated by reference in its entirety.
[0095] The leaflets 40 can be secured to one another at their
adjacent sides to form commissures 122 of the leaflet structure
(FIG. 20). A plurality of flexible connectors 124 (one of which is
shown in FIG. 16) can be used to interconnect pairs of adjacent
sides of the leaflets and to mount the leaflets to the commissure
window frame portions 30 (FIG. 5). FIG. 16 shows the adjacent sides
of two leaflets 40 interconnected by a flexible connector 124.
Three leaflets 40 can be secured to each other side-to-side using
three flexible connectors 124, as shown in FIG. 17. Additional
information regarding connecting the leaflets to each other, as
well as connecting the leaflets to the frame, can be found, for
example, in U.S. Patent Application Publication No. 2012/0123529,
which is incorporated by reference herein in its entirety.
[0096] As noted above, the inner skirt 16 can be used to assist in
suturing the leaflet structure 14 to the frame. The inner skirt 16
can have an undulating temporary marking suture to guide the
attachment of the lower edges of each leaflet 40. The inner skirt
16 itself can be sutured to the struts of the frame 12 using
sutures 70, as noted above, before securing the leaflet structure
14 to the skirt 16. The struts that intersect the marking suture
desirably are not attached to the inner skirt 16. This allows the
inner skirt 16 to be more pliable in the areas not secured to the
frame and minimizes stress concentrations along the suture line
that secures the lower edges of the leaflets to the skirt. As noted
above, when the skirt is secured to the frame, the fibers 78, 80 of
the skirt (see FIG. 12) generally align with the angled struts of
the frame to promote uniform crimping and expansion of the
frame.
[0097] FIG. 18 shows one specific approach for securing the
commissure portions 122 of the leaflet structure 14 to the
commissure window frame portions 30 of the frame. The flexible
connector 124 (FIG. 17) securing two adjacent sides of two leaflets
is folded widthwise and the upper tab portions 112 are folded
downwardly against the flexible connector. Each upper tab portion
112 is creased lengthwise (vertically) to assume an L-shape having
a first portion 142 folded against a surface of the leaflet and a
second portion 144 folded against the connector 124. The second
portion 144 can then be sutured to the connector 124 along a suture
line 146. Next, the commissure tab assembly is inserted through the
commissure window 20 of a corresponding window frame portion 30,
and the folds outside of the window frame portion 30 can be sutured
to portions 144.
[0098] FIG. 18 also shows that the folded down upper tab portions
112 can form a double layer of leaflet material at the commissures.
The first portions 142 of the upper tab portions 112 are positioned
flat against layers of the two leaflets 40 forming the commissures,
such that each commissure comprises four layers of leaflet material
just inside of the window frames 30. This four-layered portion of
the commissures can be more resistant to bending, or articulating,
than the portion of the leaflets 40 just radially inward from the
relatively more-rigid four-layered portion. This causes the
leaflets 40 to articulate primarily at inner edges 143 of the
folded-down first portions 142 in response to blood flowing through
the prosthetic valve during operation within the body, as opposed
to articulating about or proximal to the axial struts of the window
frames 30. Because the leaflets articulate at a location spaced
radially inwardly from the window frames 30, the leaflets can avoid
contact with and damage from the frame. However, under high forces,
the four layered portion of the commissures can splay apart about a
longitudinal axis adjacent to the window frame 30, with each first
portion 142 folding out against the respective second portion 144.
For example, this can occur when the prosthetic valve 10 is
compressed and mounted onto a delivery shaft, allowing for a
smaller crimped diameter. The four-layered portion of the
commissures can also splay apart about the longitudinal axis when
the balloon catheter is inflated during expansion of the prosthetic
valve, which can relieve some of the pressure on the commissures
caused by the balloon, reducing potential damage to the commissures
during expansion.
[0099] After all three commissure tab assemblies are secured to
respective window frame portions 30, the lower edges of the
leaflets 40 between the commissure tab assemblies can be sutured to
the inner skirt 16. For example, as shown in FIG. 19, each leaflet
40 can be sutured to the inner skirt 16 along suture line 154
using, for example, Ethibond Excel.RTM. PET thread. The sutures can
be in-and-out sutures extending through each leaflet 40, the inner
skirt 16, and each reinforcing strip 72. Each leaflet 40 and
respective reinforcing strip 72 can be sewn separately to the inner
skirt 16. In this manner, the lower edges of the leaflets are
secured to the frame 12 via the inner skirt 16. As shown in FIG.
19, the leaflets can be further secured to the skirt with blanket
sutures 156 that extend through each reinforcing strip 72, leaflet
40 and the inner skirt 16 while looping around the edges of the
reinforcing strips 72 and leaflets 40. The blanket sutures 156 can
be formed from PTFE suture material. FIG. 20 shows a side view of
the frame 12, leaflet structure 14 and the inner skirt 16 after
securing the leaflet structure 14 and the inner skirt 16 to the
frame 12 and the leaflet structure 14 to the inner skirt 16.
[0100] FIG. 21 is a flattened view of the outer skirt 18 prior to
its attachment to the frame 12, showing the outer surface of the
skirt. FIG. 22 is a flattened view of the outer skirt 18 prior to
its attachment to the frame 12, showing the inner surface of the
skirt. FIG. 23 is a perspective view of the outer skirt prior to
its attachment to the frame 12. The outer skirt 18 can be laser cut
or otherwise formed from a strong, durable material such as PET or
various other suitable synthetic or natural materials configured to
restrict and/or prevent blood-flow therethrough. The outer skirt 18
can comprise a substantially straight lower (inflow or upstream)
edge portion 160 and an upper (outflow or downstream) edge portion
162 defining a plurality of alternating projections 164 and notches
166, or castellations, that generally follow the shape of a row of
struts of the frame. The lower and upper edge portions 160, 162 can
have other shapes in alternative embodiments. For example, in one
implementation, the lower edge portion 160 can be formed with a
plurality of projections generally conforming to the shape of a row
of struts of the frame 12, while the upper edge portion 162 can be
straight.
[0101] In particular embodiments, the outer skirt 18 can comprise
at least one soft, plush surface 168 oriented radially outward so
as to cushion and seal against native tissues surrounding the
prosthetic valve. In certain examples, the outer skirt 18 can be
made from any of a variety of woven, knitted, or crocheted fabrics
wherein the surface 168 is the surface of a plush nap or pile of
the fabric. Exemplary fabrics having a pile include velour, velvet,
velveteen, corduroy, terrycloth, fleece, etc. As best shown in FIG.
23, the outer skirt can have a base layer 170 (a first layer) from
which a pile layer 172 (a second layer) extends. The base layer 170
can comprise warp and weft yarns woven or knitted into a mesh-like
structure. For example, in a representative configuration, the
yarns of the base layer 170 can be flat yarns and can have a denier
range of from about 7 dtex to about 100 dtex, and can be knitted
with a density of from about 20 to about 100 wales per inch and
from about 30 to about 110 courses per inch. The yarns can be made
from, for example, biocompatible thermoplastic polymers such as
PET, PTFE (polytetrafluoroethylene), Nylon, etc., or any other
suitable natural or synthetic fibers.
[0102] The pile layer 172 can comprise pile yarns 174 woven or
knitted into loops. In certain configurations, the pile yarns 174
can be the warp yarns or the weft yarns of the base layer 170 woven
or knitted to form the loops. The pile yarns 174 can also be
separate yarns incorporated into the base layer, depending upon the
particular characteristics desired. In a representative
configuration, the pile yarns 174 can be flat yarns and can have a
denier range of from about 7 dtex to about 100 dtex, and can be
knitted with a density of from about 20 to about 100 wales per inch
and from about 30 to about 110 courses per inch. The pile yarns can
be made from, for example, biocompatible thermoplastic polymers
such as PET, PTFE, Nylon, etc., or any other suitable natural or
synthetic fibers.
[0103] In certain embodiments, the loops can be cut such that the
pile layer 172 is a cut pile in the manner of, for example, a
velour fabric. FIGS. 1 and 21 illustrate a representative
embodiment of the outer skirt 18 configured as a velour fabric. In
other embodiments, the loops can be left intact to form a looped
pile in the manner of, for example, terrycloth. FIG. 23 illustrates
a representative embodiment of the outer skirt 18 in which the pile
yarns 174 are knitted to form loops 176.
[0104] The height of the pile yarns 174 (e.g., the loops 176) can
be the same for all pile yarns across the entire extent of the
outer skirt so as to provide an outer skirt having a constant
thickness. In alternative embodiments, the height of the pile yarns
174 can vary along the height and/or circumference of the outer
skirt so as to vary the thickness of the outer skirt along its
height and/or circumference, as further described below.
[0105] The pile layer 172 has a much greater surface area than
similarly sized skirts formed from flat or woven materials, and
therefore can enhance tissue ingrowth compared to known skirts.
Promoting tissue growth into the pile layer 172 can decrease
perivaluvular leakage, increase retention of the valve at the
implant site and contribute to long-term stability of the valve. In
some configurations, the surface area of the pile yarns 174 can be
further increased by using textured yarns having an increased
surface area due to, for example, a wavy or undulating structure.
In configurations such as the looped pile embodiment of FIG. 23,
the loop structure and the increased surface area provided by the
textured yarn of the loops 176 can allow the loops to act as a
scaffold for tissue growth into and around the loops of the
pile.
[0106] The outer skirt embodiments described herein can also
contribute to improved compressibility and shape memory properties
of the outer skirt over known valve coverings and skirts. For
example, the pile layer 172 can be compliant such that it
compresses under load (e.g., when in contact with tissue, other
implants, or the like), and returns to its original size and shape
when the load is relieved. This can help to improve sealing between
the outer skirt and the tissue of the native annulus, or a
surrounding support structure in which the prosthetic valve is
deployed. Embodiments of an implantable support structure that is
adapted to receive a prosthetic valve and retain it within the
native mitral valve are disclosed in co-pending Application No.
62/449,320, filed Jan. 23, 2017, and application Ser. No.
15/876,053, filed Jan. 19, 2018, which are incorporated herein by
reference. The compressibility provided by the pile layer 172 of
the outer skirt 18 is also beneficial in reducing the crimp profile
of the valve. Additionally, the outer skirt 18 can prevent the
leaflets 40 or portions thereof from extending through spaces
between the struts of the frame 12 as the prosthetic valve is
crimped, thereby protecting against damage to the leaflets due to
pinching of the leaflets between struts.
[0107] In alternative embodiments, the outer skirt 18 be made of a
non-woven fabric such as felt, or fibers such as non-woven cotton
fibers. The outer skirt 18 can also be made of porous or spongey
materials such as, for example, any of a variety of compliant
polymeric foam materials, or woven fabrics, such as woven PET.
[0108] Various techniques and configurations can be used to secure
the outer skirt 18 to the frame 12 and/or the inner skirt 16. As
best shown in FIG. 3, a lower edge portion 180 of the inner skirt
16 can be wrapped around the inflow end 15 of the frame 12, and the
lower edge portion 160 of the outer skirt 18 can be attached to the
lower edge portion 180 of the inner skirt 16 and/or the frame 12,
such as with one or more sutures or stitches 182 (as best shown in
FIG. 2) and/or an adhesive. In lieu of or in addition to sutures,
the outer skirt 18 can be attached to the inner skirt 16, for
example, by ultrasonic welding. In the illustrated embodiment, the
lower edge portion 160 of the outer skirt 18 can be free of loops,
and the lower edge portion 180 of the inner skirt 16 can overlap
and can be secured to the base layer 170 of the outer skirt 18. In
other embodiments, the lower edge portion 180 of the inner skirt 16
can extend over one or more rows of loops 176 of the pile layer 172
(see FIG. 27), as further described below. In other embodiments,
the lower edge portion 180 of the inner skirt 18 can be wrapped
around the inflow end of the frame and extend between the outer
surface of the frame and the outer skirt 18 (i.e., the outer skirt
18 is radially outward of the lower edge portion 180 of the inner
skirt 18).
[0109] As shown in FIG. 1, each projection 164 of the outer skirt
18 can be attached to the third row III of struts 26 (FIG. 5) of
the frame 12. The projections 164 can, for example, be wrapped over
respective struts 26 of row III and secured with sutures 184. The
outer skirt 18 can be further secured to the frame 12 by suturing
an intermediate portion of the outer skirt (a portion between the
lower and upper edge portions) to struts of the frame, such as
struts 24 of the second row II of struts.
[0110] The height of the outer skirt (as measured from the lower
edge to the upper edge) can vary in alternative embodiments. For
example, in some embodiments, the outer skirt can cover the entire
outer surface of the frame 12, with the lower edge portion 160
secured to the inflow end of the frame 12 and the upper edge
portion secured to the outflow end of the frame. In another
embodiment, the outer skirt 18 can extend from the inflow end of
the frame to the second row II of struts 24, or to the fourth row
IV of struts 28, or to a location along the frame between two rows
of struts. In still other embodiments, the outer skirt 18 need not
extend all the way to the inflow end of the frame, and instead the
inflow end of the outer skirt can secured to another location on
the frame, such as to the second row II of struts 24.
[0111] The outer skirt 18 desirably is sized and shaped relative to
the frame such that when the prosthetic valve 10 is in its radially
expanded state, the outer skirt 18 fits snugly (in a tight-fitting
manner) against the outer surface of the frame. When the prosthetic
valve 10 is radially compressed to a compressed state for delivery,
the portion of the frame on which the outer skirt is mounted can
elongate axially. The outer skirt 18 desirably has sufficient
elasticity to stretch in the axial direction upon radial
compression of the frame so that it does not to prevent full radial
compression of the frame or deform the struts during the crimping
process.
[0112] Known skirts that have material slack or folds when the
prosthetic valve is expanded to its functional size are difficult
to assemble because the material must be adjusted as it is sutured
to the frame. In contrast, because the outer skirt 18 is sized to
fit snugly around the frame in its fully expanded state, the
assembly process of securing the skirt to the frame is greatly
simplified. During the assembly process, the outer skirt can be
placed around the frame with the frame in its fully expanded state
and the outer skirt in its final shape and position when the valve
is fully functional. In this position, the skirt can then be
sutured to the frame and/or the inner skirt. This simplifies the
suturing process compared to skirts that are designed to have slack
or folds when radially expanded.
[0113] As shown in FIG. 3, the height of the loops of the pile
layer 172 can be constant across the entire extent of the outer
skirt such that the outer skirt 18 has a constant thickness, except
along the upper and lower edge portions which can be free of loops
to facilitate attachment of the outer skirt to the frame and/or the
inner skirt 16. The "height" of the loops is measured in the radial
direction when the skirt is mounted on the frame. In another
embodiment, as shown in FIG. 24, the loops can comprise lower loops
176a along the lower or upstream portion of the skirt that are
relatively shorter in height (as represented by a thinner
cross-sectional area) than upper loops 176b (as represented by a
thicker cross-sectional area) along the upper or downstream portion
of the skirt. The skirt 18 can further include a group of
intermediate loops 176c that gradually increase in height from the
lower loops 176a to the upper loops 176b. Thus, in the embodiment
of FIG. 24, the thickness of outer skirt 18 increases from a
minimum thickness along the lower portion to a maximum thickness
along the upper portion.
[0114] FIG. 25 shows another embodiment in which the loops of the
outer skirt comprise lower loops 176d along the lower portion of
the skirt that are relatively higher or longer in height than upper
loops 176e along the upper portion of the skirt. The skirt 18 can
further include a group of intermediate loops 176f that gradually
decrease in height from the lower loops 176d to the upper loops
176e. Thus, in the embodiment of FIG. 25, the thickness of outer
skirt 18 decreases from a maximum thickness along the lower portion
to a minimum thickness along the upper portion.
[0115] FIG. 26 shows another embodiment in which the loops comprise
lower loops 176g, upper loops 176h, and intermediate loops 176i
that are relative shorter in height than the lower and upper loops.
As shown, the lower loops 176g can gradually decrease in height
from the lower edge of the skirt toward the intermediate loops
176i, and the upper loops 176h can gradually decrease in height
from the upper edge of the skirt toward the intermediate loops
176i. Thus, in the embodiment of FIG. 26, the thickness of the
outer skirt decreases from a maximum thickness along the lower
portion to a minimum thickness along the intermediate portion, and
then increases from the intermediate portion to the maximum
thickness along the upper portion. In the illustrated embodiment,
the upper portion of the skirt containing the upper loops 176h has
the same thickness as the lower portion of the skirt containing the
lower loops 176g. In other embodiments, the thickness of the upper
portion of the skirt containing the upper loops 176h can be greater
or less than the same thickness of the lower portion of the skirt
containing the lower loops 176g.
[0116] Further, in any of the embodiments described above where the
height of the loops vary along the height of the skirt, the height
of the loops need not vary gradually from one section of the skirt
to another section of the skirt. Thus, an outer skirt can have
loops of different heights, wherein the height of the loops change
abruptly at locations along the skirt. For example, in the
embodiment of FIG. 24, the lower portion of the skirt containing
the lower loops 176a can extend all the way to the upper portion of
the skirt containing the upper loops 176g without the intermediate
loops 176c forming a transition between the upper and lower
portions.
[0117] In lieu of or in addition to having loops that vary in
height along the height of the skirt, the height of the loops 176
(and therefore the thickness of the outer skirt) can vary along the
circumference of the outer skirt. For example, the height of the
loops can be increased along circumferential sections of the skirt
where larger gaps might be expected between the outer skirt and the
native annulus, such as circumferential sections of the skirt that
are aligned with the commissures of the native valve.
[0118] FIGS. 27 and 28 show an alternative configuration for
mounting the outer skirt 18 to the frame 12. In this embodiment, as
best shown in FIG. 27, the lower edge portion 180 of the inner
skirt 16 is wrapped around the inflow end of the frame and extended
over one or more rows of loops along the lower edge portion 160 of
the outer skirt. The lower edge portion 180 of the inner skirt 16
can then be secured to the lower edge portion 160 of the outer
skirt, such as with sutures or stitching 186 (FIG. 28), an
adhesive, and/or welding (e.g., ultrasonic welding). The stitching
186 can also extend around selected struts adjacent the inflow end
of the frame. The lower edge portion 180 of the inner skirt is
effective to partially compress the loops of the pile layer 172,
which creates a tapered edge at the inflow end of the prosthetic
valve. The tapered edge reduces the insertion force required to
push the prosthetic valve through an introducer sheath when being
inserted into a patient's body. In one specific implementation, the
stitching 186 secures the lower edge portion 180 of the inner skirt
to the outer skirt 18 at a distance of at least 1 mm from the
lowermost edge of the outer skirt. The upper edge portion 162 and
the intermediate portion of the outer skirt can then be secured to
the frame as previously described.
[0119] FIGS. 29-32 show another configuration for mounting the
outer skirt 18 to the frame 12. In this embodiment, the outer skirt
18 is initially placed in a tubular configuration with the base
layer 170 facing outwardly and the lower edge portion 160 (which
can be free of loops 176) can be placed between the inner surface
of the frame 12 and the lower edge portion 180 of the inner skirt
16, as depicted in FIG. 30. The lower edge portions of the outer
skirt and the inner skirt can be secured to each other, such as
with stitches, an adhesive, and/or welding (e.g., ultrasonic
welding). In one implementation, the lower edge portions of the
outer skirt and the inner skirt are secured to each other with
in-and-out stitches and locking stitches. The outer skirt 18 is
then inverted and pulled upwardly around the outer surface of the
frame 12 such that the base layer 170 is placed against the outer
surface of the frame and the pile layer 172 faces outwardly, as
depicted in FIG. 29. In this assembled configuration, the lower
edge portion 160 of the outer skirt wraps around the inflow end of
the frame and is secured to the inner skirt inside of the frame.
The upper edge portion 162 and the intermediate portion of the
outer skirt can then be secured to the frame as previously
described.
[0120] The prosthetic valve 10 can be configured for and mounted on
a suitable delivery apparatus for implantation in a subject.
Several catheter-based delivery apparatuses are known; a
non-limiting example of a suitable catheter-based delivery
apparatus includes that disclosed in U.S. Patent Application
Publication No. 2013/0030519, which is incorporated by reference
herein in its entirety, and U.S. Patent Application Publication No.
2012/0123529.
[0121] To implant a plastically-expandable prosthetic valve 10
within a patient, the prosthetic valve 10 including the outer skirt
18 can be crimped on an elongated shaft of a delivery apparatus.
The prosthetic valve, together with the delivery apparatus, can
form a delivery assembly for implanting the prosthetic valve 10 in
a patient's body. The shaft can comprise an inflatable balloon for
expanding the prosthetic valve within the body. With the balloon
deflated, the prosthetic valve 10 can then be percutaneously
delivered to a desired implantation location (e.g., a native aortic
valve region). Once the prosthetic valve 10 is delivered to the
implantation site (e.g., the native aortic valve) inside the body,
the prosthetic valve 10 can be radially expanded to its functional
state by inflating the balloon or equivalent expansion
mechanism.
[0122] The outer skirt 18 can fill-in gaps between the frame 12 and
the surrounding native annulus to assist in forming a good,
fluid-tight seal between the prosthetic valve 10 and the native
annulus. The outer skirt 18 therefore cooperates with the inner
skirt 16 to avoid perivalvular leakage after implantation of the
prosthetic valve 10. Additionally, as discussed above, the pile
layer of the outer skirt further enhances perivalvular sealing by
promoting tissue ingrowth with the surrounding tissue.
[0123] Alternatively, a self-expanding prosthetic valve 10 can be
crimped to a radially collapsed configuration and restrained in the
collapsed configuration by inserting the prosthetic valve 10,
including the outer skirt 18, into a sheath or equivalent mechanism
of a delivery catheter. The prosthetic valve 10 can then be
percutaneously delivered to a desired implantation location. Once
inside the body, the prosthetic valve 10 can be advanced from the
delivery sheath, which allows the prosthetic valve to expand to its
functional state.
[0124] FIG. 33 illustrates a sealing member 200 for a prosthetic
valve, according to another embodiment. The sealing member 200 in
the illustrated embodiment is formed from a spacer fabric. The
sealing member 200 can be positioned around the outer surface of
the frame 12 of a prosthetic valve (in place of the outer skirt 18)
and secured to the inner skirt 16 and/or the frame using stitching,
an adhesive, and/or welding (e.g., ultrasonic welding).
[0125] As best shown in FIG. 34, the spacer fabric can comprise a
first, inner layer 206, a second, outer layer 208, and an
intermediate spacer layer 210 extending between the first and
second layers to create a three-dimensional fabric. The first and
second layers 206, 208 can be woven fabric or mesh layers. In
certain configurations, one or more of the first and second layers
206, 208 can be woven such that they define a plurality of openings
212. In some examples, openings such as the openings 212 can
promote tissue growth into the sealing member 200. In other
embodiments, the layers 206, 208 need not define openings, but can
be porous, as desired.
[0126] The spacer layer 210 can comprise a plurality of pile yarns
214. The pile yarns 214 can be, for example, monofilament yarns
arranged to form a scaffold-like structure between the first and
second layers 206, 208. For example, FIGS. 34 and 35 illustrate an
embodiment in which the pile yarns 214 extend between the first and
second layers 206, 208 in a sinusoidal or looping pattern.
[0127] In certain examples, the pile yarns 214 can have a rigidity
that is greater than the rigidity of the fabric of the first and
second layers 206, 208 such that the pile yarns 214 can extend
between the first and second layers 206, 208 without collapsing
under the weight of the second layer 208. The pile yarns 214 can
also be sufficiently resilient such that the pile yarns can bend or
give when subjected to a load, allowing the fabric to compress, and
return to their non-deflected state when the load is removed. For
example, when the prosthetic valve is radially compressed for
delivery into a patient's body and placed in a delivery sheath of a
delivery apparatus or advanced through an introducer sheath, the
pile yarns 214 can compress to reduce the overall crimp profile of
the prosthetic valve, and then return to their non-deflected state
when deployed from the delivery sheath or the introducer sheath, as
the case may be.
[0128] The spacer fabric can be warp-knitted, or weft-knitted, as
desired. Some configurations of the spacer cloth can be made on a
double-bar knitting machine. In a representative example, the yarns
of the first and second layers 206, 208 can have a denier range of
from about 10 dtex to about 70 dtex, and the yarns of the
monofilament pile yarns 214 can have a denier range of from about 2
mil to about 10 mil. The pile yarns 214 can have a knitting density
of from about 20 to about 100 wales per inch, and from about 30 to
about 110 courses per inch. Additionally, in some configurations
(e.g., warp-knitted spacer fabrics) materials with different
flexibility properties may be incorporated into the spacer cloth to
improve the overall flexibility of the spacer cloth.
[0129] FIG. 36 shows an outer sealing member 18' mounted on the
outside of the frame 12 of a prosthetic heart valve 10, according
to another embodiment. FIG. 37 shows the base layer 170 of the
sealing member 18' in a flattened configuration. FIG. 38 shows the
pile layer 172 of the sealing member 18' in a flattened
configuration. The outer sealing member 18' is similar to the
sealing member 18 of FIGS. 1 and 21-23, except that the height
(H.sub.1) of the base layer 170 is greater than the height
(H.sub.2) of the pile layer 172 Like the previously described
embodiments, the sealing member 18' desirably is sized and shaped
relative to the frame 12 such that when the prosthetic valve is in
its radially expanded state, both layers 170, 172 of the sealing
member 18 fit snugly (in a tight-fitting manner) around the outer
surface of the frame.
[0130] In the illustrated configuration, the base layer 170 extends
axially from the inlet end of the frame 12 to the third row III of
struts 26 of the frame 12. The upstream and downstream edges of the
base layer 170 can be sutured to the struts 22 of the first row I
and to the struts 26 of the third row III with sutures 182 and 184,
respectively, as previously described. The pile layer 172 in the
illustrated configuration extends from the inlet end of the frame
12 to a plane that intersects the frame at the nodes formed at the
intersection of the upper ends of struts 24 of the second row II
and the lower ends of struts 26 of the third row III, wherein the
plane is perpendicular to the central axis of the frame.
[0131] The pile layer 172 can be separately formed from and
subsequently attached to the base layer 170, such as with sutures,
an adhesive, and/or welding. Alternatively, the pile layer 172 can
be formed from yarns or fibers woven into the base layer 170. The
pile layer 172 can have any of the configurations shown in FIGS.
24-26.
[0132] In particular embodiments, the height H.sub.1 of the base
layer 170 can be about 9 mm to about 25 mm or about 13 mm to about
20 mm, with about 19 mm being a specific example. The height
H.sub.2 of the pile layer 172 can be at least 2 mm less than
H.sub.1, at least 3 mm less than H.sub.1, at least 4 mm less than
H.sub.1, at least 5 mm less than H.sub.1, at least 6 mm less than
H.sub.1, at least 7 mm less than H.sub.1, at least 8 mm less than
H.sub.1, at least 9 mm than H.sub.1, or at least 10 mm less than
H.sub.1. The height of the frame 12 in the radially expanded state
can be about 12 mm to about 27 mm or about 15 mm to about 23 mm,
with about 20 mm being a specific example.
[0133] The relatively shorter pile layer 172 reduces the crimp
profile along the mid-section of the prosthetic valve 10 but still
provides for enhanced paravalvular sealing along the majority of
the landing zone of the prosthetic valve. The base layer 170 also
provides a sealing function downstream of the downstream edge of
the pile layer 172.
[0134] FIGS. 39-40 show an outer sealing member 300 for a
prosthetic heart valve (e.g., a prosthetic heart valve 10),
according to another embodiment. FIGS. 39A and 40A are magnified
views of portions of the sealing member shown in FIGS. 39 and 40,
respectively. The sealing member 300 can be mounted on the outside
of the frame 12 of a prosthetic valve 10 in lieu of sealing member
18 using, for example, sutures, ultrasonic welding, or any other
suitable attachment method. Like the previously described
embodiments, the sealing member 300 desirably is sized and shaped
relative to the frame 12 such that when the prosthetic valve is in
its radially expanded state, the sealing member 300 fits snugly (in
a tight-fitting manner) against the outer surface of the frame.
[0135] The sealing member 300, like sealing members 18, 18', can be
a dual-layer fabric comprising a base layer 302 and a pile layer
304. FIG. 39 shows the outer surface of the sealing member 300
defined by the pile layer 304. FIG. 40 shows the inner surface of
the sealing member 300 defined by the base layer 302. The base
layer 302 in the illustrated configuration comprises a mesh weave
having circumferentially extending rows or stripes 306 of
higher-density mesh portions interspersed with rows or stripes 308
of lower-density mesh portions.
[0136] In particular embodiments, the yarn count of yarns extending
in the circumferential direction (side-to-side or horizontally in
FIGS. 40 and 40A) is greater in the higher-density rows 306 than in
the lower-density rows 308. In other embodiments, the yarn count of
yarns extending in the circumferential direction and the yarn count
of yarns extending in the axial direction (vertically in FIGS. 40
and 40A) is greater in the higher-density rows 306 than in the
lower-density rows 308.
[0137] The pile layer 304 can be formed from yarns woven into the
base layer 302. For example, the pile layer 304 can comprise a
velour weave formed from yarns incorporated in the base layer 302.
The pile layer 304 can comprise circumferentially extending rows or
stripes 310 of pile formed at axially-spaced locations along the
height of the sealing member 300 such that there are axial
extending gaps between adjacent rows 310. In this manner, the
density of the pile layer varies along the height of the sealing
member. In alternative embodiments, the pile layer 304 can be
formed without gaps between adjacent rows of pile, but the pile
layer can comprise circumferentially extending rows or stripes of
higher-density pile interspersed with rows or stripes 312 of
lower-density pile.
[0138] In alternative embodiments, the base layer 302 can comprise
a uniform mesh weave (the density of the weave pattern is uniform)
and the pile layer 304 has a varying density.
[0139] Varying the density of the pile layer 304 and/or the base
layer 302 along the height of the sealing member 300 is
advantageous in that it facilitates axially elongation of the
sealing member 300 caused by axial elongation of the frame 12 when
the prosthetic heart valve is crimped to a radially compressed
state for delivery. The varying density also reduces the bulkiness
of the sealing member in the radially collapsed state and therefore
reduces the overall crimp profile of the prosthetic heart
valve.
[0140] In alternative embodiments, the density of the sealing
member 300 can vary along the circumference of the sealing member
to reduce the bulkiness of the sealing member in the radially
collapsed state. For example, the pile layer 304 can comprise a
plurality of axially-extending, circumferentially-spaced, rows of
pile yarns, or alternatively, alternating axially-extending rows of
higher-density pile interspersed with axially-extending rows of
lower-density pile. Similarly, the base layer 302 can comprise a
plurality axially-extending rows of higher-density mesh
interspersed with rows of lower-density mesh.
[0141] In other embodiments, the sealing member 300 can include a
base layer 302 and/or a pile layer 304 that varies in density along
the circumference of the sealing member and along the height of the
sealing member.
[0142] In other embodiments, a sealing member can be knitted,
crocheted, or woven to have rows or sections of higher stitch
density and rows or sections of lower stitch density without two
distinct layers. FIG. 41, for example, shows a sealing member 400
comprising a fabric having a plurality of axially-extending rows
402 of higher-density stitching alternating with axially-extending
rows 404 of lower-density stitching. The sealing member 400 can be
formed, for example, by knitting, crocheting, or weaving a single
layer fabric having rows 402, 404 formed by increasing the stitch
density along the rows 402 and decreasing the stitch density along
the rows 404 while the fabric is formed. The sealing member 400 can
be mounted on the outside of the frame 12 of a prosthetic valve 10
in lieu of sealing member 18 using, for example, sutures,
ultrasonic welding, or any other suitable attachment method. Like
the previously described embodiments, the sealing member 400
desirably is sized and shaped relative to the frame 12 such that
when the prosthetic valve is in its radially expanded state, the
sealing member 400 fits snugly (in a tight-fitting manner) against
the outer surface of the frame.
[0143] The sealing member 400 can be resiliently stretchable
between a first, substantially relaxed, axially foreshortened
configuration (FIG. 41) corresponding to a radially expanded state
of the prosthetic valve, and a second, axially elongated, or
tensioned configuration (FIG. 42) corresponding to a radially
compressed state of the prosthetic valve. As shown in FIG. 41, when
the prosthetic valve is radially expanded and the sealing member
400 is in the first configuration, the higher-density rows 402
extend in an undulating pattern from the lower (upstream edge) to
the upper (downstream edge) of the sealing member 400. In the
illustrated embodiment, for example, each of the higher-density
rows 402 comprises a plurality of straight angled sections 406a,
406b arranged end-to-end in a zig-zag or herringbone pattern
extending from the lower (upstream edge) to the upper (downstream
edge) of the sealing member 400. In alternative embodiments, the
rows 402 can be sinusoidal-shaped rows having curved longitudinal
edges.
[0144] When the prosthetic valve is crimped to its radially
compressed state, the frame 12 elongates, causing the sealing
member to stretch in the axial direction, as depicted in FIG. 42,
to its second configuration. The lower-density rows 404 facilitate
elongation of the sealing member and permit straightening of the
higher-density rows 402. FIG. 42 depicts the higher-density rows
402 as straight sections extending from the inflow edge to the
outflow edge of the sealing member. However, it should be
understood that the higher-density rows 402 need not form perfectly
straight rows when the prosthetic valve is in the radially
compressed state. Instead, "straightening" of the higher-density
rows 402 occurs when the angle 408 between adjacent angled segments
406a, 406b of each row increases upon axial elongation of the
sealing member.
[0145] The varying stitch density of the sealing member 400 reduces
overall bulkiness of the sealing member to minimize the crimp
profile of the prosthetic valve. The zig-zag or undulating pattern
of the higher-density rows 402 in the radially expanded state of
the prosthetic valve facilitates stretching of the sealing member
in the axial direction upon radial compression of the prosthetic
valve and allows the sealing member to return to its pre-stretched
state in which the sealing member fits snugly around the frame upon
radial expansion of the prosthetic valve. Additionally, the zig-zag
or undulating pattern of the higher-density rows 402 in the
radially expanded state of the prosthetic valve eliminates any
straight flow paths for blood between adjacent rows 402 extending
along the outer surface of the sealing member from its outflow edge
to its inflow edge to facilitate sealing and tissue ingrowth with
surrounding tissue.
[0146] In alternative embodiments, a sealing member 400 can have a
plurality of circumferentially extending higher-density rows (like
rows 402 but extending in the circumferential direction)
interspersed with a plurality of circumferentially extending
lower-density rows (like rows 404 but extending in the
circumferential direction). In some embodiments, a sealing member
400 can have axially-extending and circumferential-extending
higher-density rows interspersed with axially-extending and
circumferential-extending lower-density rows.
[0147] FIGS. 43A, 43B, 44A, and 44B illustrate an outer sealing
member 500 for a prosthetic heart valve (e.g., a prosthetic heart
valve 10), according to another embodiment. The sealing member 500
can have a plush exterior surface 504. The sealing member 500 can
be secured to a frame 12 of the prosthetic valve using, for
example, sutures, ultrasonic welding, or any other suitable
attachment method as previously described herein. For purposes of
illustration, enlarged or magnified portions of the sealing member
500 are shown in the figures. It should be understood that the
overall size and shape of the sealing member 500 can be modified as
needed to cover the entire outer surface of the frame 12 or portion
of the outer surface of the frame, as previously described
herein.
[0148] The sealing member 500 can comprise a woven or knitted
fabric. The fabric can be resiliently stretchable between a first,
natural, or relaxed configuration (FIG. 43A), and a second, axially
elongated, or tensioned configuration (FIG. 43B). When disposed on
the frame 12, the relaxed configuration can correspond to the
radially expanded, functional configuration of the prosthetic
valve, and the elongated configuration can correspond to the
radially collapsed delivery configuration of the prosthetic valve.
Thus, with reference to FIG. 43A, the sealing member 500 can have a
first length L.sub.1 in the axial direction when the prosthetic
valve is in the radially expanded configuration, and a second
length L.sub.2 (FIG. 43B) in the axial direction that is longer
than L.sub.1 when the valve is crimped to the delivery
configuration, as described in greater detail below.
[0149] The fabric can comprise a plurality of circumferentially
extending warp yarns 512 and a plurality of axially extending weft
yarns 514. In some embodiments, the warp yarns 512 can have a
denier of from about 1 D to about 300 D, about 10 D to about 200 D,
or about 10 D to about 100 D. In some embodiments, the warp yarns
512 can have a thickness t.sub.1 (FIG. 44A) of from about 0.01 mm
to about 0.5 mm, about 0.02 mm to about 0.3 mm, or about 0.03 mm to
about 0.1 mm. In some embodiments, the warp yarns 512 can have a
thickness t.sub.1 of about 0.03 mm, about 0.04 mm, about 0.05 mm,
about 0.06 mm, about 0.07 mm, about 0.08 mm, about 0.09 mm, or
about 0.1 mm. In a representative embodiment, the warp yarns 512
can have a thickness of about 0.06 mm.
[0150] The weft yarns 514 can be texturized yarns comprising a
plurality of texturized filaments 516. For example, the filaments
516 of the weft yarns 514 can be bulked, wherein, for example, the
filaments 516 are twisted, heat set, and untwisted such that the
filaments retain their deformed, twisted shape in the relaxed,
non-stretched configuration. The filaments 516 can also be
texturized by crimping, coiling, etc. When the weft yarns 514 are
in a relaxed, non-tensioned state, the filaments 516 can be loosely
packed and can provide compressible volume or bulk to the fabric,
as well as a plush surface. In some embodiments, the weft yarns 514
can have a denier of from about 1 D to about 500 D, about 10 D to
about 400 D, about 20 D to about 350 D, about 20 D to about 300 D,
or about 40 D to about 200 D. In certain embodiments, the weft
yarns 514 can have a denier of about 150 D. In some embodiments, a
filament count of the weft yarns 514 can be from 2 filaments per
yarn to 200 filaments per yarn, 10 filaments per yarn to 100
filaments per yarn, 20 filaments per yarn to 80 filaments per yarn,
or about 30 filaments per yarn to 60 filaments per yarn.
Additionally, although the axially-extending textured yarns 514 are
referred to as weft yarns in the illustrated configuration, the
fabric may also be manufactured such that the axially-extending
textured yarns are warp yarns and the circumferentially-extending
yarns are weft yarns.
[0151] FIGS. 44A and 44B illustrate a cross-sectional view of the
sealing member in which the weft yarns 512 extend into the plane of
the page. With reference to FIG. 44A, the fabric of the sealing
member 500 can have a thickness t.sub.2 of from about 0.1 mm to
about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 5 mm,
about 1 mm to about 3 mm, about 0.5 mm, about 1 mm, about 1.5 mm,
about 2 mm, about 2.5 mm, or about 3 mm when in a relaxed state and
secured to a frame. In some embodiments, the sealing member 500 can
have a thickness of about 0.1 mm, about 0.2 mm, about 0.3 mm, about
0.4 mm, or about 0.5 mm as measured in a relaxed state with a
weighted drop gauge having a presser foot. In a representative
example, the sealing member can have a thickness of about 1.5 mm
when secured to a prosthetic valve frame in the relaxed state. The
texturized, loosely packed filaments 516 of the weft yarns 514 in
the relaxed state can also promote tissue growth into the sealing
member 500.
[0152] When the fabric is in the relaxed state, the textured
filaments 516 of the weft yarns 514 can be widely dispersed such
that individual weft yarns are not readily discerned, as depicted
in FIG. 43A. When tensioned in the axial direction, the filaments
516 of the weft yarns 514 can be drawn together as the weft yarns
elongate and the kinks, twists, etc., of the filaments are pulled
straight such that the fabric is stretched and the thickness
decreases. In certain embodiments, when sufficient tension is
applied to the fabric in the axial direction (the weft direction in
the illustrated embodiment), such as when the prosthetic valve is
crimped onto a shaft of a delivery apparatus, the textured fibers
516 can be pulled together such that individual weft yarns 514
become discernable, as best shown in FIG. 43B.
[0153] Thus, for example, when fully stretched, the sealing member
can have a second thickness t.sub.3, as shown in FIG. 44B that is
less than the thickness t.sub.2. In certain embodiments, the
thickness of the tensioned weft yarns 514 may be the same or nearly
the same as the thickness t.sub.1 of the warp yarns 512. Thus, in
certain examples, when stretched the fabric can have a thickness
t.sub.3 that is the same or nearly the same as three times the
thickness t.sub.1 of the warp yarns 512 depending upon, for
example, the amount of flattening of the weft yarns 514.
Accordingly, in the example above in which the warp yarns 512 have
a thickness of about 0.06 mm, the thickness of the sealing member
can vary between about 0.2 mm and about 1.5 mm as the fabric
stretches and relaxes. Stated differently, the thickness of the
fabric can vary by 750% or more as the fabric stretches and
relaxes.
[0154] Additionally, as shown in FIG. 44A, the warp yarns 512 can
be spaced apart from each other in the fabric by a distance y.sub.1
when the outer covering is in a relaxed state. As shown in FIGS.
43B and 44B, when tension is applied to the fabric in the direction
perpendicular to the warp yarns 512 and parallel to the weft yarns
514, the distance between the warp yarns 512 can increase as the
weft yarns 514 lengthen. In the example illustrated in FIG. 44B, in
which the fabric has been stretched such that the weft yarns 514
have lengthened and narrowed to approximately the diameter of the
warp yarns 512, the distance between the warp yarns 512 can
increase to a new distance y.sub.2 that is greater than the
distance y.sub.1.
[0155] In certain embodiments, the distance y.sub.1 can be, for
example, about 1 mm to about 10 mm, about 2 mm to about 8 mm, or
about 3 mm to about 5 mm. In a representative example, the distance
y.sub.1 can be about 3 mm. In some embodiments, when the fabric is
stretched as in FIGS. 43B and 44B, the distance y.sub.2 can be
about 6 mm to about 10 mm. Thus, in certain embodiments, the length
of the sealing member 500 in the axial direction can vary by 100%
or more between the relaxed length L.sub.1 and the fully stretched
length (e.g., L.sub.2). The fabric's ability to lengthen in this
manner facilitates crimping of the prosthetic valve. Thus, the
sealing member 500 can be soft and voluminous when the prosthetic
valve is expanded to its functional size, and relatively thin when
the prosthetic valve is crimped to minimize the overall crimp
profile of the prosthetic valve.
General Considerations
[0156] It should be understood that the disclosed embodiments can
be adapted to deliver and implant prosthetic devices in any of the
native annuluses of the heart (e.g., the pulmonary, mitral, and
tricuspid annuluses), and can be used with any of various
approaches (e.g., retrograde, antegrade, transseptal,
transventricular, transatrial, etc.). The disclosed embodiments can
also be used to implant prostheses in other lumens of the body.
Further, in addition to prosthetic valves, the delivery assembly
embodiments described herein can be adapted to deliver and implant
various other prosthetic devices such as stents and/or other
prosthetic repair devices.
[0157] For purposes of this description, certain aspects,
advantages, and novel features of the embodiments of this
disclosure are described herein. The disclosed methods, apparatus,
and systems should not be construed as being limiting in any way.
Instead, the present disclosure is directed toward all novel and
nonobvious features and aspects of the various disclosed
embodiments, alone and in various combinations and sub-combinations
with one another. The methods, apparatus, and systems are not
limited to any specific aspect or feature or combination thereof,
nor do the disclosed embodiments require that any one or more
specific advantages be present or problems be solved.
[0158] Although the operations of some of the disclosed embodiments
are described in a particular, sequential order for convenient
presentation, it should be understood that this manner of
description encompasses rearrangement, unless a particular ordering
is required by specific language set forth below. For example,
operations described sequentially may in some cases be rearranged
or performed concurrently. Moreover, for the sake of simplicity,
the attached figures may not show the various ways in which the
disclosed methods can be used in conjunction with other methods.
Additionally, the description sometimes uses terms like "provide"
or "achieve" to describe the disclosed methods. These terms are
high-level abstractions of the actual operations that are
performed. The actual operations that correspond to these terms may
vary depending on the particular implementation and are readily
discernible by one of ordinary skill in the art.
[0159] As used in this application and in the claims, the singular
forms "a," "an," and "the" include the plural forms unless the
context clearly dictates otherwise. Additionally, the term
"includes" means "comprises." Further, the terms "coupled" and
"associated" generally mean electrically, electromagnetically,
and/or physically (e.g., mechanically or chemically) coupled or
linked and does not exclude the presence of intermediate elements
between the coupled or associated items absent specific contrary
language.
[0160] As used herein, the term "proximal" refers to a position,
direction, or portion of a device that is closer to the user and
further away from the implantation site. As used herein, the term
"distal" refers to a position, direction, or portion of a device
that is further away from the user and closer to the implantation
site. Thus, for example, proximal motion of a device is motion of
the device toward the user, while distal motion of the device is
motion of the device away from the user. The terms "longitudinal"
and "axial" refer to an axis extending in the proximal and distal
directions, unless otherwise expressly defined.
[0161] As used herein, the terms "integrally formed" and "unitary
construction" refer to a construction that does not include any
welds, fasteners, or other means for securing separately formed
pieces of material to each other.
[0162] As used herein, operations that occur "simultaneously" or
"concurrently" occur generally at the same time as one another,
although delays in the occurrence of one operation relative to the
other due to, for example, spacing, play or backlash between
components in a mechanical linkage such as threads, gears, etc.,
are expressly within the scope of the above terms, absent specific
contrary language.
[0163] In view of the many possible embodiments to which the
principles of the disclosed invention may be applied, it should be
recognized that the illustrated embodiments are only preferred
examples of the invention and should not be taken as limiting the
scope of the invention. Rather, the scope of the invention is
defined by the following claims. We therefore claim as our
invention all that comes within the scope and spirit of these
claims.
* * * * *