U.S. patent application number 14/541944 was filed with the patent office on 2015-03-12 for prosthetic heart valves.
This patent application is currently assigned to ST. JUDE MEDICAL, INC.. The applicant listed for this patent is St. Jude Medical, Inc.. Invention is credited to Peter N. Braido.
Application Number | 20150073546 14/541944 |
Document ID | / |
Family ID | 39708341 |
Filed Date | 2015-03-12 |
United States Patent
Application |
20150073546 |
Kind Code |
A1 |
Braido; Peter N. |
March 12, 2015 |
PROSTHETIC HEART VALVES
Abstract
A prosthetic heart valve (e.g., a prosthetic aortic valve) is
designed to be somewhat circumferentially collapsible and then
re-expandable. The collapsed condition may be used for less
invasive delivery of the valve into a patient. When the valve
reaches the implant site in the patient, it re-expands to normal
operating size, and also to engage surrounding tissue of the
patient. The valve includes a stent portion and a ring portion that
is substantially concentric with the stent portion but downstream
from the stent portion in the direction of blood flow through the
implanted valve. When the valve is implanted, the stent portion
engages the patient's tissue at or near the native valve annulus,
while the ring portion engages tissue downstream from the native
valve site (e.g., the aorta).
Inventors: |
Braido; Peter N.; (Wyoming,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
St. Jude Medical, Inc. |
St. Paul |
MN |
US |
|
|
Assignee: |
ST. JUDE MEDICAL, INC.
St. Paul
MN
|
Family ID: |
39708341 |
Appl. No.: |
14/541944 |
Filed: |
November 14, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12451678 |
Nov 24, 2009 |
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PCT/US2008/007015 |
Jun 4, 2008 |
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14541944 |
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60933274 |
Jun 4, 2007 |
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Current U.S.
Class: |
623/2.18 |
Current CPC
Class: |
A61F 2210/0076 20130101;
A61L 27/54 20130101; A61F 2230/008 20130101; A61F 2/2418 20130101;
A61L 27/3604 20130101; A61F 2220/0016 20130101; A61F 2220/0075
20130101; A61F 2230/0054 20130101 |
Class at
Publication: |
623/2.18 |
International
Class: |
A61F 2/24 20060101
A61F002/24; A61L 27/54 20060101 A61L027/54; A61L 27/36 20060101
A61L027/36 |
Claims
1-31. (canceled)
32. A prosthetic heart valve, comprising: a collapsible and
expandable stent having a proximal end, a distal end, an annulus
section adjacent the proximal end and an aortic section adjacent
the distal end, the stent having a first convex curvature and a
second concave curvature proximal to the first curvature; a
collapsible and expandable valve assembly disposed within the stent
and including a plurality of leaflets; and a cuff annularly
disposed about the valve assembly in the annulus section.
33. The prosthetic heart valve of claim 32, wherein the annulus
portion includes a lower skirt adjacent the proximal end, and the
second concave curvature is at least partially defined by the lower
skirt.
34. The prosthetic heart valve of claim 33, wherein lower skirt
extends radially outward.
35. The prosthetic heart valve of claim 33, wherein the lower skirt
is configured and arranged to complement a shape of a native valve
annulus.
36. The prosthetic heart valve of claim 32, wherein the first and
second curvatures on the stent are smooth and define a partially
sinusoidal profile.
37. The prosthetic heart valve of claim 33, wherein the lower skirt
has a constant curvature around the circumference of the stent.
38. The prosthetic heart valve of claim 33, wherein the lower skirt
has a variable curvature around the circumference of the stent.
39. The prosthetic heart valve of claim 33, wherein the lower skirt
has a scalloped free edge.
40. The prosthetic heart valve of claim 33, wherein a diameter of
the lower skirt decreases from the proximal end of the stent toward
the distal end of the stent.
41. The prosthetic heart valve of claim 33, wherein a diameter of
the lower skirt at the proximal end of the stent is the largest
diameter of the stent along a length of the stent.
42. The prosthetic heart valve of claim 33, wherein the lower skirt
is configured to apply a force to a bottom of a native valve
annulus when implanted.
43. The prosthetic heart valve of claim 33, wherein the lower skirt
is configured and arranged to conform to a curvature of a bottom of
a native valve annulus to reduce paravalvular leakage.
44. The prosthetic heart valve of claim 32, wherein the plurality
of leaflets includes three leaflets.
45. The prosthetic heart valve of claim 32, wherein the plurality
of leaflets includes tissue.
46. The prosthetic heart valve of claim 32, wherein a first portion
of the stent is more resistant to annular compression than a second
portion of the stent.
47. A prosthetic heart valve, comprising: a collapsible and
expandable stent having a proximal end, a distal end, an annulus
section adjacent the proximal end and an aortic section adjacent
the distal end, the stent having a concave lower skirt portion in
the annulus section that deflects radially outwardly at the
proximal end; a collapsible and expandable valve assembly disposed
within the stent and including a plurality of leaflets; and a cuff
annularly disposed about the valve assembly in the annulus
section.
48. A prosthetic heart valve, comprising: a collapsible and
expandable stent having a proximal end, a distal end, and an
annulus section adjacent the proximal end; a collapsible and
expandable valve assembly disposed within the stent and including a
plurality of leaflets; and at least two layers material annularly
disposed on the valve assembly in the annulus section adjacent the
proximal end of the stent, the at least two layers at least
partially overlapping one another.
49. The prosthetic heart valve of claim 48, wherein the at least
two layers include a first layer disposed on a luminal surface of
the stent, and a second layer disposed on an abluminal surface of
the stent.
50. The prosthetic heart valve of claim 49, wherein the first layer
and the second layer are continuous with one another.
51. The prosthetic heart valve of claim 49, wherein the first layer
and the second layer are formed of a single web of material that is
folded at a fold line corresponding to a bottom edge of the stent
adjacent the proximal end.
52. The prosthetic heart valve of claim 49, wherein the first layer
extends a first distance from a bottom edge of the stent toward the
distal end of the stent and the second layer extends a second
distance from the bottom edge of the stent toward the distal end of
the stent, the first distance and the second distance being
equal.
53. The prosthetic heart valve of claim 49, wherein the first layer
extends a first distance from a bottom edge of the stent toward the
distal end of the stent and the second layer extends a second
distance from the bottom edge of the stent toward the distal end of
the stent, the first distance and the second distance being
unequal.
54. The prosthetic heart valve of claim 49, wherein the first layer
extends a first distance from a bottom edge of the stent toward the
distal end of the stent and the second layer extends a second
distance from the bottom edge of the stent toward the distal end of
the stent, the first distance being greater than the second
distance.
55. The prosthetic heart valve of claim 49, wherein the first layer
and the second layer include at least two different materials.
56. The prosthetic heart valve of claim 49, wherein at least one of
the first layer and the second layer includes a fabric.
57. The prosthetic heart valve of claim 49, wherein at least one of
the first layer and the second layer includes at least one of
Dacron, polyester or Teflon.
58. The prosthetic heart valve of claim 49, wherein at least one of
the first layer and the second layer includes a material selected
to promote tissue in-growth.
59. The prosthetic heart valve of claim 49, wherein at least one of
the first layer and the second layer includes tissue.
60. The prosthetic heart valve of claim 48, wherein the at least
two layers include a fabric layer and a tissue layer.
61. The prosthetic heart valve of claim 49, wherein the stent
includes a plurality of cells arranged in annular rows around the
stent and the second layer extends over at least one full row of
the cells.
62. The prosthetic heart valve of claim 49, wherein the stent
includes a plurality of cells arranged in annular rows around the
stent and the second layer extends over at least a portion of one
of the rows of the cells.
Description
[0001] This application claims the benefit of U.S. provisional
patent application 60/933,274, filed Jun. 4, 2007, which is hereby
incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] This invention relates to prosthetic heart valves. For the
most part, the invention will be illustratively described in the
context of a prosthetic aortic valve that can be temporarily
collapsed during a portion of the implantation procedure, and that
can be subsequently expanded to its full size at the implantation
site. The invention is not necessarily limited to this particular
type of use, however, and it will be appreciated that various
aspects of the invention can be used in other ways and/or in other
contexts.
[0003] Many people with severe aortic stenosis go untreated because
they are not considered to be suitable candidates for aortic valve
replacement using the known prostheses and procedures (e.g.,
open-chest, open-heart surgery). In an attempt to provide ways of
treating these patients, collapsible prosthetic valves have been
developed for insertion within stenotic aortic valve leaflets in
less invasive ways. For example, such less invasive delivery of the
prosthetic valve may be via catheter-like, trocar-like, or
laparoscopic-type instrumentation. The delivery may be percutaneous
(e.g., via vessels of the patient's circulatory system that lead to
the aortic valve), or it may be through the wall of the heart
(e.g., through the apex of the left ventricle of the heart (i.e.,
transapically)), etc. It is believed, however, that current designs
for prosthetic valves that are to be delivered in ways such as
these are in need of improvement with respect to aspects such as
(1) long-term durability, (2) the possibility of undesirable
impingement on the adjacent mitral valve, (3) paravalvular leakage,
etc.
BRIEF SUMMARY OF THE INVENTION
[0004] A prosthetic heart valve in accordance with the invention
may include an annular supporting structure that has (1) an annular
stent portion and (2) a ring portion that is substantially
concentric with the stent portion but that is downstream from the
stent portion in the direction of blood flow through the valve when
the valve is in use in a patient. The stent portion has a
blood-outflow region that includes a plurality of annularly spaced
commissure tips at which the stent portion is closest to the ring
portion. The ring portion is connected to the stent portion
substantially solely by flexible strut structures that extend from
the stent portion to the ring portion adjacent to the commissure
tips. Each of the strut structures starts from a respective point
or points on the stent structure that are farther from the ring
portion than the commissure tips. The valve further includes a
plurality of valve leaflets supported by the stent portion. The
ring portion is downstream from the stent portion sufficiently far
that the leaflets cannot contact the ring portion.
[0005] The supporting structure is preferably annularly
compressible and re-expandable. The stent portion is preferably
adapted to engage tissue of the patient at or near the native heart
valve annulus of the patient. (This engagement may be through other
material that has been used to cover the stent portion.) The ring
portion is adapted to engage the inside of a blood vessel of the
patient downstream from the native heart valve annulus. (Again,
this engagement may be through other material that has been used to
cover the ring portion.)
[0006] The ring portion may be integrally connected to the stent
portion. The ring portion and the stent portion may be annularly
compressible to substantially the same circumference. The ring
portion may be re-expandable to a circumferential size that is
greater than the circumferential size of at least a part of the
stent portion when the stent portion is re-expanded.
[0007] The stent portion may include a skirt portion that is
adjacent to the blood inflow end of the valve when the valve is in
use in a patient. The skirt portion may re-expand to flare radially
out from a remainder of the stent portion. The inflow end of the
stent portion (e.g., the skirt) may be scalloped in an annular
direction around the heart valve to avoid impingement on another of
the patient's heart valves or other structures in the patient's
heart.
[0008] The supporting structure may include barbs that engage
tissue of the patient when the valve is in use.
[0009] The ring portion may be constructed so that it is more
resistant to annular compression than the stent portion.
[0010] The stent portion may include a blood-outflow-edge structure
that comprises (1) a first ring member that extends annularly
around the valve in a serpentine pattern and that has a relatively
large number of connections to other upstream structure of the
stent portion, and (2) a second ring member that (a) follows the
first ring member annularly around the valve in a similar
serpentine pattern, (b) is spaced downstream from the first ring
member, and (c) has a relatively small number of connections to the
first ring member. The ring portion may be attached to the stent
portion by connections between the ring portion and the second ring
member. The last-mentioned connections may connect to points on the
second ring member that are closest to the ring portion. Portions
of each of the leaflets may be inserted between the first and
second ring members.
[0011] Sheet material (e.g., fabric and/or tissue) may be provided
for covering at least part of the stent portion and/or at least
part of the ring portion. Any of this sheet material may be
attached to the inside and/or outside of the stent portion and/or
the ring portion. Such sheet material covering may comprise one
layer or more than one layer. Different sheet materials may be used
at different locations; and where multiple layers are used,
different sheet materials may be used in various combinations in
different layers. If the valve includes the above-mentioned first
and second ring members, then sheet material (of an above-mentioned
type) may be provided for covering the first and/or second ring
members. If leaflet portions are inserted between the first and
second ring members, then sheet material may be interposed between
the leaflets and the first and second ring members.
[0012] Further features of the invention, its nature and various
advantages, will be more apparent from the accompanying drawings
and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a simplified elevational view of an illustrative
embodiment of a component of a prosthetic heart valve in accordance
with the invention.
[0014] FIG. 2 is a simplified isometric or perspective view of the
FIG. 1 component.
[0015] FIG. 3 shows the component of FIGS. 1 and 2 cut at one
location around its perimeter and basically flattened out (although
not all parts of the structure are shown lying in one plane such as
the plane of the paper on which FIG. 3 is drawn).
[0016] FIG. 4 is a simplified perspective or isometric view of what
is shown in FIG. 3.
[0017] FIG. 5 is a simplified, partial, elevational view of a
component that is at least generally similar to what is shown in
FIG. 1.
[0018] FIG. 6 is similar to a lower portion of FIG. 5, but with the
full annular structure shown, and with the addition of another
component also shown.
[0019] FIG. 7 is similar to FIG. 6, but with another additional
component shown.
[0020] FIG. 8 is again similar to FIG. 5, but with the full annular
structure and still more added components shown.
[0021] FIG. 9 is a simplified elevational view of an illustrative
embodiment of a complete prosthetic heart valve in accordance with
the invention.
[0022] FIG. 10 shows a representative portion of a structure like
that shown in several earlier FIGS., with certain parts emphasized
with special shading for purposes of further discussion.
[0023] FIG. 11 is a simplified depiction of what is shown in FIG.
10 from the direction indicated by the arrows 11-11 in FIG. 10.
[0024] FIG. 12 is similar to FIG. 3, but for another illustrative
embodiment in accordance with the invention and in another
operating condition.
[0025] FIG. 13 is an enlargement of a portion of FIG. 12.
[0026] FIG. 14 shows the FIG. 12 structure in the round and fully
expanded.
[0027] FIG. 15 is similar to FIG. 12 for yet another illustrative
embodiment of the invention.
[0028] FIG. 16 is similar to FIG. 14, but for the FIG. 15
embodiment.
[0029] FIG. 17 is similar to FIG. 15 for still another illustrative
embodiment of the invention.
[0030] FIG. 18 is similar to FIG. 16, but for the FIG. 17
embodiment.
[0031] FIG. 19 is similar to FIG. 18, but with some further
components added.
[0032] FIG. 20 is similar to FIG. 17 for yet another illustrative
embodiment of the invention.
[0033] FIG. 21 is similar to FIG. 20 for still another illustrative
embodiment of the invention.
[0034] FIG. 22 is similar to FIG. 21 for yet another illustrative
embodiment of the invention.
[0035] FIG. 23 is similar to FIG. 22 for still another illustrative
embodiment of the invention.
[0036] FIG. 24 is a simplified isometric or perspective view
showing the FIG. 23 structure in its circumferentially expanded
state or condition.
[0037] FIG. 25 is a simplified partial isometric or perspective
view showing another illustrative embodiment of the invention.
[0038] FIG. 26 is similar to FIG. 24 for yet another illustrative
embodiment of the invention.
[0039] FIG. 27 is similar to FIG. 26 for still another illustrative
embodiment of the invention.
[0040] FIG. 28 is a simplified view looking down on a lower part of
the structure shown in FIG. 25.
[0041] FIG. 29 is a simplified view similar to FIG. 28 with an
illustrative embodiment of possible further components added in
accordance with the invention.
[0042] FIG. 30 is a simplified view similar to FIG. 29 with an
illustrative embodiment of still more components added in
accordance with the invention.
[0043] FIG. 31 is a simplified elevational view of an illustrative
embodiment of a component that can be used in valves in accordance
with the invention.
[0044] FIG. 32 is a simplified side view (flattened out to a plane)
of an illustrative embodiment of a representative portion of what
is shown in FIG. 30 in accordance with the invention.
[0045] FIG. 33 is similar to FIG. 29 for another illustrative
embodiment in accordance with the invention.
[0046] FIG. 34 is again similar to FIG. 29 for yet another
illustrative embodiment in accordance with the invention.
[0047] FIG. 35 is similar to FIG. 31 for another illustrative
embodiment in accordance with the invention.
[0048] FIG. 36 is again similar to FIG. 29 for still another
illustrative embodiment in accordance with the invention.
DETAILED DESCRIPTION
[0049] This detailed description will begin with discussion of an
illustrative embodiment of a primary metal component 10 (initially
with reference to FIGS. 1-4) that is included in valves in
accordance with the invention. Other possible components of a
complete valve may be mentioned in this discussion of component 10,
but more attention will be given to such possible other components
later in this specification. The valves of this invention are
collapsible and expandable in the circumferential direction. FIGS.
1-4 and other early FIGS. show illustrative embodiments of these
valves (or portions or components of these valves) in their
circumferentially expanded condition configuration. Some of the
later FIGS. illustrate how valves of this type circumferentially
collapse. Alternative terms that may be used for circumferential
(in the context of collapse and re-expansion of a valve) include
annular (in the sense of ring-like (especially like a closed
ring)), diametrical, radial, and the like.
[0050] The valves of this invention can be used in patients who
need an aortic valve replacement, but who may not be treated
adequately by currently available prostheses and/or procedures.
Valves in accordance with this invention can be implanted
percutaneously, transapically, or surgically, with or without
resected and/or debrided native leaflets. Metal component 10 can be
cut from a highly elastic and/or shape-memory alloy (e.g., nitinol)
so that it is self-expanding, or from another metal (e.g.,
stainless steel, cobalt-chromium, platinum-iridium, etc.) that
necessitates balloon expansion after annular reduction. A way that
metal component 10 can be made is by using a laser to cut it from
starting stock that is a metal tube. Alternatively, metal component
10 can be laser-cut from a flat metal sheet and then rolled into a
hollow annulus in which the formerly free ends or side edges of the
flat material are joined together by any suitable means such as
welding.
[0051] Component 10 may have any or all of the features that are
described in the following paragraphs.
[0052] Illustrative component 10 includes a collapsible and
expandable "upper" ring portion 100, and a collapsible and
expandable "lower" stent portion 200 (which is also a ring). (The
words "upper" and "lower" are used only as convenient, relative
terms, and without any intention to limit what is referenced to any
particular orientation relative to some absolute reference
direction). In general, the stent portion 200 surrounds the
leaflets of the prosthetic valve. The blood inflow end or edge of
the valve is at or adjacent the lower end or edge of stent portion
200 as viewed in FIG. 1. The blood outflow end or edge of the valve
is at or adjacent the upper end of stent portion 200 as viewed in
FIG. 1. Ring portion 100 is downstream from stent portion 200 in
terms of the direction of blood flow through the valve. Moreover,
the annular structure of ring portion 100 is preferably downstream
from the reach of any portion of the leaflets of the valve in any
operating position of these leaflets so that no portion of the
leaflets can ever contact any significant portion of at least the
annular structure of ring portion 100. Indeed, when the valve is in
use in a patient, ring portion 100 is typically disposed in the
patient's aorta downstream from the valsalva sinus.
[0053] Ring portion 100 and stent portion 200 both include a number
of cells (each of which has a closed perimeter surrounding an open
center) that are collapsible and expandable in a direction that is
circumferential around component 10. Reference number 110 points to
a typical such cell in ring portion 100, and reference number 210
points to a typical such cell in stent portion 200. Making
component 10 of such cells contributes to the ability of component
10 to shrink (collapse) and/or expand in the circumferential
direction. Ring portion 100 may have cells of different sizes than
the cells of stent portion 200 in order to facilitate ring portion
100 reaching a different, finally expanded diameter than stent
portion 200. For example, it may be desirable for ring portion 100
to reach a final expanded diameter that is greater than the final
expanded diameter of stent portion 200. This may enable ring
portion 100 to better fill and bear against the adjacent portion of
a patient's aorta (e.g., at or near the sinotubular junction (where
the aortic sinus bulge ends and the aorta begins)), while stent
portion only has to fill and bear against the patient's
diametrically smaller aortic valve annulus. Cells 110 in ring
portion 100 that are larger than cells 210 in stent portion 200 may
help ring portion 100 expand to the above-mentioned larger final
diameter.
[0054] Differential radial force may also be provided by ring
portion 100 and stent portion 200. For example, it may be desirable
for ring portion 100 to provide more radial force (to the adjacent
aorta wall) than stent portion 200 provides (to the native aortic
valve annulus). Larger cells (like 110) with "heavier" metal sides
in ring portion 100 (as compared to stent portion 200) can
contribute to causing ring portion 100 to apply more radially
outward force than stent portion 200. A side of a cell that is
"heavier" has a larger cross section (more material) than a cell
side that is "lighter." Thus it will be noted that the sides of
cell 110 are heavier (wider and/or thicker) than the sides of cell
210.
[0055] In general, the provision of ring portion 100 allows for
greater overall structural integrity of component (and hence the
valve as a whole), while distributing holding forces more evenly.
For example, this can avoid the need for a high-radial-force stent,
which could cause undesirable deformation of the patient's mitral
valve (which is adjacent to the aortic valve). This better, more
widely distributed holding force can also reduce the need to use
the patient's native, possibly stenotic leaflets (if present) as
the primary anchoring mechanism for the prosthetic valve.
[0056] Illustrative component 10 includes barbs 120 that are placed
on the distal (downstream) portion of the ring 100 that expands
into the aorta. Barbs 120 (which point in the downstream direction)
help prevent migration (especially downstream shifting) of the
implanted valve. Other generally similar barbs can be employed at
various other locations on component 10 to help prevent valve
migration. For example, barbs can be provided that point upstream,
downstream, clockwise, counter-clockwise, or in any other
direction, and they can be provided on ring portion 100, stent
portion 200, or both.
[0057] The lower (blood inflow edge) portion of stent portion 200
is designed to conform to the anatomy of the heart without
impinging on the patient's mitral valve. In particular it will be
noted that adjacent one of the three commissure posts or regions of
component 10 (i.e., at reference 220a) the inflow edge of component
10 is higher than it is adjacent the other two commissure posts or
regions (i.e., at references 220b and 220c). A valve including
component 10 is preferably implanted so that higher inflow edge
portion 220a is adjacent to the patient's mitral valve. This helps
prevent the prosthetic valve from impinging on the mitral valve.
This low profile of stent portion 200 means the area adjacent to
the mitral valve is designed to reduce the possibility of chordal
entanglement and mitral valve impingement. In general, the
stent/valve is designed to reduce interference with various
anatomical and/or physiological constraints. Such constraints may
include avoidance of mitral valve impingement, avoidance of chordae
entanglement, avoidance of interference with the heart's various
electrical conduction system pathways, etc.
[0058] Dual open bars 130 are provided for connecting ring portion
100 to stent portion 200 in the vicinity of the tip of each
commissure region of stent portion 200. This allows for redundant
support in a high stress area, while also allowing some bending
and/or twisting to conform to the patient's anatomy.
[0059] Stent portion 200 includes an independent stent-in-stent
design as indicated at references 230a and 230b. In particular,
stent portion 200 includes two congruent, serpentine,
blood-outflow-edge-region members 230a and 230b. Each of these
members 230 is a ring that extends annularly all the way around
stent portion 200. Each of these members 230 undulates alternately
up and down as one proceeds in the annular direction around the
valve so that each member is "high" near the tip of each of three
commissure regions 236 of the valve, and "low" between each
annularly adjacent pair of such commissure regions. ("High" means
extending farther in the blood flow direction; "low" means
extending not as far in the blood flow direction. This undulation
of members 230 may also be referred to as a serpentine pattern.)
Everywhere in the annular direction around component 10 member 230b
is higher than (i.e., spaced downstream from) member 230a. At
several locations 232 that are spaced from one another annularly
around component 10 connections or links are provided between
members 230a and 230b. Elsewhere, however, members 230a and 230b
are able to move relative to one another. Hence the description of
this structure as an "independent stent-in-stent design."
[0060] This independent stent-in-stent design facilitates good
leaflet coaptation near the top of each commissure post 236, while
helping to maintain a flexible stent. This increased flexibility
(which may contrast with designs that use a straight vertical bar
for each commissure post region) may reduce stress concentration on
the leaflets (which may be tissue, for example). Reduced leaflet
stress concentration is conducive to longer valve life or
durability. Amplifying what is being said about flexibility, making
structure 230a relatively independent of structure 230b in the
vicinity of stent posts 236 means that the stent posts (actually
provided by structure 230a and not structure 230b) can be made as
flexible as is desired. The relatively independent valve anchoring
structure (e.g., ring 100, the lower portion of stent 200, and the
structures 130 and 230b that link the two) can be made stiffer
(relatively less flexible) for completely secure anchoring of the
valve in the implant site.
[0061] As shown in FIGS. 3 and 4, a lower "skirt" portion 240 of
stent 200 and/or ring 100 can be deflected out of projections of
the tubular geometric figure in which the major portion of stent
200 lies. In particular, these deflections may be radially outward
from the above-mentioned tubular geometric figure projections.
These radially outwardly projecting portions of component 10 (along
with some radially outward force from the midsection of stent
portion 200) help hold the implanted valve in place in the patient
with or without the patient's native, stenotic leaflets to help
hold it in place.
[0062] The smooth contours (in the annular direction) of the
outflow edge 230a/230b of stent portion 200 may facilitate the use
of naturally contoured leaflets. This may be unlike other designs
that use a vertical bar for each commissure region. Additionally,
this smooth outflow edge may help reduce or eliminate stagnant
blood flow zones, which might otherwise arise where a leaflet
abruptly changes direction at the bottom of a vertical bar. The
above-mentioned smooth outflow edge contour is the result of
outflow edge members 230a/230b being smoothly serpentine or
undulating in the annular direction around structure 10.
[0063] Although component 10 includes a ring 100 in the patient's
aorta, there are large openings 140 between stent portion 200 and
ring portion 100 to allow for blood flow to freely pass to the
coronary arteries. These large openings 140 also reduce the chance
of leaflet abrasion from the free edge due to leaflet contact with
other parts of the prosthetic valve structure.
[0064] As has been mentioned, different cell dimensions in
different parts of component 10 allow for different amounts of
expansion and force generation in different parts of the device.
Some of this cell structure can be converted to other
circumferentially expandable structure (e.g., serpentine or
undulating members extending generally in the circumferential
direction) to allow for different types of behavior (e.g., with
respect to amount of expansion and/or amount of force that can be
generated).
[0065] To further reduce or eliminate leaflet abrasion at the
leaflet attachment site, stent portion 200 can first be covered
with fabric, followed by a thin layer of buffering tissue, and
finally leaflet tissue. Inventive aspects of this kind will be
discussed in more detail later in this specification.
[0066] The elongated slots 234 between the two
blood-outflow-edge-region members 230a and 230b allow for (1) a
flexible stent (as discussed earlier in this specification), (2)
uninterrupted suturing of other materials such as leaflets over
structure 10 (as opposed to smaller stent holes hidden beneath
those other materials), (3) easily polished edges, and (4) a
reduction in stress concentration from point suturing.
[0067] Skirt portion 240 can be scalloped (e.g., higher and less
radially deflected in area 220a than elsewhere around structure
10). This can allow skirt 240 to conform more readily to the
natural contours of the patient's aortic annulus, which may improve
the placement and holding force of the prosthetic valve, as well as
helping to reduce or eliminate paravalvular leakage.
[0068] Bends in certain areas like 150a, 150b, 150c, and 250 can
result in component 10 having different diameters at different
points along its length. ("Length" refers to distance or location
along the axis of blood flow through the device. A "bend" is
typically a deflection about a geometric circumference of the
device. FIG. 4 shows what will be the inner surface of component 10
in a finished valve. The outer surface of component 10 is not
visible in FIG. 4.) Again, different diameters of component 10 at
different locations along the length of that component allow the
valve to better conform to adjacent structures in the patient's
anatomy (e.g., the aorta toward the upper end of component 10, or
the sub-annular geometry toward the lower end of component 10).
[0069] By conforming to the portion of the heart below the aortic
valve, the holding force and paravalvular seal is improved.
[0070] The upper portion of the stent-in-stent design (e.g., in
areas like those referenced 236 and 130) can be contoured to the
shape of the patient's native aortic root. By this it is meant that
these upper portions of the stent-in-stent design can gradually
taper outward with the aorta since the aorta is larger than the
native valve annulus. This can provide additional anchoring of the
prosthetic valve to the patient's anatomy.
[0071] Another possibility is to have this portion (e.g., upper
serpentine member 230b) bend away (i.e., radially outwardly) from
other adjacent portions of the valve) to more gradually slope to
the aorta diameter. This can allow for this section to be
completely out of the way of the leaflet tissue attachments or free
edges.
[0072] Component 10 can be partially or completely covered in one
or more layers of material or combinations of materials (e.g.,
polyester, tissue, etc.). This layer or layers can allow for such
things as better tissue in-growth, abrasion protection, sealing,
and protection from metal leachables such as nickel from nitinol.
Again, various aspects of how component 10 can be covered will be
considered in more detail later in this specification.
[0073] FIG. 5 shows a side view of an embodiment of component 10 in
which the radial shaping is more fully developed and depicted in at
least some of the various ways that are shown and described earlier
in this specification. FIG. 5 shows only one side (approximately
half) of component 10. The opposite side (i.e., the rear half) is
omitted from FIG. 5 for greater clarity. It will be noted that
component 10 in FIG. 5 has different diameters at different points
along its length. (Diameters are horizontal in FIG. 5. Length is
vertical in FIG. 5 (parallel to the axis of blood flow through a
finished and implanted valve).) Diameter changes in FIG. 5 tend to
be relatively smooth. Even the rate of diameter change tends to be
relatively smooth (not too abrupt at any point along the length of
the device) throughout component 10 in FIG. 5. Note again the base
skirt flare 240 and the expanded section 100 for the aorta in FIG.
5. As mentioned earlier, the base flare helps to secure the valve
in place, and also to direct blood flow and prevent leakage around
the outside of the valve (paravalvular leakage). Another possible
feature that is shown in FIG. 5 (and carried through into some
subsequent FIGS. like FIGS. 8 and 9) is contouring or curving of
aortic ring 100 radially inwardly at the tips (i.e., at both the
lower (upstream) tips like 103 and the upper (downstream) tips like
105). This can help reduce or avoid perforation and/or dissection
of the aorta by ring portion 100. The embodiment of component 10
that is shown in FIG. 5 is used as the component 10 in the series
of FIGS. that will be discussed next.
[0074] FIG. 6 illustrates a possible first step in attachment of
other material to component 10. FIG. 6 and subsequent FIGS. tend to
show the added material as though it were transparent (which, in
fact, it typically is not). Thus these FIGS. tend to show the added
material, for the most part, by means of a line at the visible
limits of the material. In addition, some of these FIGS. show only
the material being added in the step that is the subject of that
FIG. Such a FIG. tends to omit depiction of material that was added
in an earlier step or steps. The earlier-added material is still
present, but it is not specifically depicted so that the FIG. that
omits its depiction can focus on the material currently being
added.
[0075] Continuing specifically with FIG. 6 (which shows only stent
portion 200 and omits depiction of ring portion 100), this FIG.
shows covering all of stent portion 200 below member 230b with a
layer of material 300 such as fabric. This covering may be both
inside and outside the covered portion of component 10. Among the
possible purposes of material 300 may be (1) promotion of tissue
in-growth, (2) blood flow/sealing, and (3) to provide an attachment
base for subsequent layers of material. All material (i.e., 300 and
subsequent material(s)) can be attached to component 10 by means of
suturing around component 10 struts and/or through dedicated
eyelets and slots (not shown) in component 10. The "X" marks in
FIG. 5 indicate some possible locations for such sutures. Examples
of fabrics that are suitable for material 300 include Dacron,
polyester, and Teflon.
[0076] FIG. 7 shows the addition of more material 400 over a
portion of material 300. (Again, as explained earlier, FIG. 7 omits
depiction of material 300 (which is still present on component 10)
so that all attention can now be given to material 400. FIG. 7 also
omits depiction of upper ring portion 100.) In particular, material
400 is applied over the upper portion of material 300, both inside
and outside the structure being built up. Material 400 may be a
lubricious covering such as tissue (e.g., pericardium from any of
several species, submucosa, and/or peritoneum) or polymer for
sealing, reduced leachables, and a buffer between the stent and the
moving leaflets. Again, the "X" marks, and now also the spiral
marks, indicate some examples of where material 400 may be sutured
to the underlying structure.
[0077] FIG. 8 illustrates addition of final material and leaflets
to the structure being built up as described in the preceding
paragraphs. A sheet of leaflet material 500 is added between each
annularly adjacent pair of commissure regions. The U-shaped "lower"
edge of each such sheet of leaflet material can be passed through
the slots 234 between members 230a and 230b and sutured to the
underlying structure. The "upper" edge of each such leaflet sheet
is the "free" edge of that leaflet. Each leaflet sheet is shaped
and includes sufficient material between the commissure regions to
which it is attached as described above so that the free edges of
the three leaflets can come together in the interior of the valve
and thereby close the valve to prevent reverse blood flow through
the valve when it is implanted and in use in a patient.
[0078] Typically after leaflets 500 have been added to the
structure being built up, a lubricious covering 600 (e.g., porcine
pericardium or polymer) may be added over member 230b. Covering 600
may also cover the lower portions of struts 130. (FIG. 8 shows
covering 600 on the foreground portions of the valve, but omits
depiction of it toward the rear to avoid over-complicating the
drawing.) Covering 600 prevents leachables and reduces any leaflet
abrasion.
[0079] In addition to elements 500 and 600, FIG. 8 shows that
material 700 (e.g., a fabric such as Dacron, polyester, or Teflon)
may or may not be provided to surround the section of component 10
that will be in contact with the aorta when the valve is in use in
a patient. If provided, such material 700 can reduce leaching of
metal and can help to secure the valve in place via tissue
in-growth. Note that if barbs 120 are present on structure 10, they
may remain uncovered for embedding into the patient's tissue.
[0080] FIG. 9 shows another illustrative embodiment of a finished
valve. The only significant difference from FIG. 8 is that in FIG.
9 material 700' covers the barbs 120 at the top of the valve. Note
that the close suturing of the various material layers to the
underlying structure leaves the perimeter limits or contours
defined by component 10 as substantially the same perimeter limits
or contours of the finished valve. As just one example of this, the
scalloping of the lower portion of component 10 (e.g., at 220a),
which is provided to avoid impinging on the patient's mitral valve,
remains a feature of the finished valve.
[0081] By way of recapitulation and further amplification of the
above, some refinement of the terminology used in the foregoing may
be helpful to better distinguish the present invention from
previously known structures. FIG. 10 shows again a portion of the
primary metal component 10 that has been shown in some of the
earlier FIGS. A portion of FIG. 10 has been shaded to emphasize the
location of a flexible strut structure 280 that connects ring
portion 100 to stent portion 200. Strut structure 280 is one of
three similar strut structures that are spaced from one another
annularly around component 10. Each strut structure 280 is located
adjacent a respective one of the three commissure regions 236 of
the valve. Ring portion 100 and stent portion 200 are connected to
one another substantially only by strut structures 280. Because
each of these strut structures is adjacent a respective one of
commissure regions 236, and because there is no other connecting
structure between ring portion 100 and stent portion 200, component
10 defines a relatively large and unobstructed opening 140 between
each annularly adjacent pair of commissure regions 236. This helps
a valve of this invention avoid occluding the ostia of the coronary
arteries. These ostia can connect to the aorta where component 10
provides large and unobstructed openings 140.
[0082] In the illustrative embodiment shown in FIG. 10,
representative strut structure 280 (shaded for emphasis)
effectively begins (toward the bottom) where member 230b is last
connected to the remainder of stent portion 200 in the blood flow
direction. This is at the uppermost links 232 that are shown in
FIG. 10. Strut structure 280 then includes the portion of member
230b that is above these uppermost links 232. Strut structure 280
also includes dual open bars 130. At its upper end strut structure
280 ends where bars 130 merge into the annular structure of ring
portion 100.
[0083] From the foregoing it will be seen that strut structure 280
connects to the remainder of stent portion 200 only well below the
upper, free-end tips of the associated commissure region 236. (In
FIG. 10 the arrow from reference number 236 points to the tip of
that commissure region.) In other words, the uppermost points of
attachment 232 of strut structure 280 to the remainder of stent
portion 200 are at a significant distance below the tip of the
associated commissure region 236. For example, if the distance from
the lowest to the highest point along the undulation of member 230a
around component 10 is H1 (see FIG. 1), and if the distance from
the highest link 232 (between members 230b and 230a) to the tip 236
of the adjacent commissure region is H2 (see FIG. 10), then H2 is
preferably about 50% or an even larger percentage of H1. Still more
preferably, H2 is about 75% or an even larger percentage of H1.
(FIGS. 1 and 10 are not, of course, drawn on the same scale.) In
other words, strut structure 280 extends down along at least about
50% (more preferably at least about 75%) of the height of the
associated commissure "post" portion of component 10 to its points
232 of attachment to the remainder of stent portion 200. In the
annular direction this downwardly extending portion of strut
structure 280 preferably closely follows the associated commissure
post (actually provided by member 230a) to avoid encroaching
significantly on the desirable large open spaces 140 between
annularly adjacent commissure regions 236.
[0084] FIG. 11 is a view taken from the side of FIG. 10 as
indicated by the line 11-11 in FIG. 10. FIG. 11 again shows
representative strut structure 280 shaded for emphasis. FIG. 11
shows that strut structure 280 can be deflected radially out from
the tubular geometric shape in which the remainder of stent portion
200 tends to lie (in this extremely simplified depiction). This
radial outward deflection of strut structure 280 can begin just
above uppermost links 232, which (as has been mentioned) can be
quite low relative to where the tips 236 of the commissure posts
are. All of this can help keep strut structure 280 away from
contact with any moving portions of the valve leaflets (anchored,
in the vicinity of what is shown in FIG. 11, to member 230a and not
to any portion of structure 280) when the valve is in use in a
patient. It can also facilitate making a gradual transition from
the smaller circumferential size of the remainder of stent portion
200 to the larger circumferential size of ring portion 100. FIG. 11
illustrates the relative independence of strut structure 280
downstream from its downstream-most connection points 232 to the
remainder of stent portion 200. This independence of strut
structures 280 and the adjacent portions of the remainder of stent
portion 200 (e.g., the adjacent portion of member 230a) allows
these features to be shaped, to deflect, and/or to flex
independently of one another (e.g., in the radial direction).
Leaflets 500 and other materials 300, 400, 600, and 700 are
preferably added and attached in such a way as to not significantly
interfere with this independence of strut structures 280 and the
adjacent parts of the remainder of stent portion 200. In other
words, leaflet and other materials and their associated attachment
sutures preferably do not span between strut structures 280 and
adjacent parts of stent portion 200 in a way that would tie these
otherwise independent features together with undue relative-motion
constraint. For example, in the vicinity of what is shown in FIG.
11, leaflet material preferably ends at member 230a (extending only
to the left from the portion of member 230a that is shown in FIG.
11). Leaflet material preferably does not extend significantly to
the right from member 230a and is preferably not attached to
structure 280 per se.
[0085] FIGS. 12-14 show the primary (tubular or hollow cylindrical)
metal component 1010 of another illustrative embodiment of a
prosthetic heart valve in accordance with this invention. Elements
in FIGS. 12-14 that are generally similar to previously described
elements have reference numbers in FIGS. 12-14 that are increased
by 1000 from the reference numbers previously used for the similar
elements. FIG. 12 shows component 1010 cut axially along its length
and then flattened (this is done solely to simplify the depiction),
but in the left-to-right condition that it has when it is annularly
compressed or collapsed. FIG. 13 shows an enlargement of the upper
portion of FIG. 12. FIG. 14 shows component 1010 in the round and
in its fully expanded state.
[0086] In the embodiment shown in FIGS. 12-14 the leaflets of the
valve can be attached to the angled posts 1260. In this embodiment
the aorta portion 1100 is made up, for the most part, of primary
serpentine members 1160a and 1160b. Each of these members undulates
in the axial direction (parallel to the axis of blood flow through
the finished and implanted valve) as one proceeds annularly around
the valve. In addition, secondary serpentine members 1162 are used
to connect members 1160a and 1160b to one another. Secondary
serpentine members 1162 undulate in the annular direction as they
proceed generally axially between members 1160a and 1160b. The use
of serpentine members 1160 and 1162 in aorta portion 1100 allows
for greater flexion and/or extension. For example, this can aid in
the flexibility of component 1010 within a catheter bending along a
tortuous path. It can allow for conformance to bending when placed
in the ascending aorta where it begins to arch. It can also
compensate for pulsatile expansion/contraction of the aorta. Stress
relieving features 1164 aid in flexibility and reduction in
stress.
[0087] As a general matter, embodiments like those shown in FIGS.
12-14 and in subsequent FIGS. may be capable of collapsing to a
smaller circumferential size than embodiments like those shown in
FIGS. 1-11. Thus, for example, any of the embodiments shown herein
may be suitable for delivery (in a collapsed condition) into the
patient through a small incision and, e.g., through the apex of the
heart. Embodiments like those shown in FIGS. 12-14 and subsequent
FIGS. may be additionally suitable for delivery in other ways
requiring collapse of the valve to an even smaller circumferential
size. An example of such other delivery is through the femoral
artery.
[0088] FIGS. 15 and 16 show the primary (tubular or hollow
cylindrical) metal component 2010 of yet another illustrative
embodiment of a prosthetic heart valve in accordance with the
invention. Elements in FIGS. 15 and 16 that are generally similar
to previously described elements have reference numbers in FIGS. 15
and 16 that are increased by 1000 or 2000 from the reference
numbers previously used for the similar elements. To simplify the
depiction, FIG. 15 shows component 2010 cut axially along its
length and then flattened, but otherwise in the condition that it
has when it is annularly compressed or collapsed. FIG. 16 shows
component 2010 in the round and in its fully expanded state. Like
the embodiment shown in FIGS. 12-14, the FIGS. 15-16 design allows
for leaflet attachment to angled posts 2260, but the FIGS. 15-16
design also has a set of apertures 2262 to aid in suturing (e.g.,
for attachment of the leaflets.) Although shown as round or
eyelet-shaped in FIGS. 15 and 16, apertures 2262 (or similar
apertures in any other embodiment) can have any other shape, if
desired. Slots are just one example of such other possible shapes
for these apertures.
[0089] FIGS. 17-19 show the primary (tubular or hollow cylindrical)
metal component 3010 of still another illustrative embodiment of a
prosthetic heart valve in accordance with the invention. Elements
in FIGS. 17-19 that are generally similar to previously described
elements have reference numbers in FIGS. 17-19 that are increased
by 1000, 2000, or 3000 from the reference numbers previously used
for the similar elements. Again, to simplify the depiction, FIG. 17
shows component 3010 cut axially along its length and then
flattened, but otherwise in the condition that it has when it is
annularly compressed or collapsed. FIG. 18 shows component 3010 in
the round and in its fully expanded state. FIG. 19 shows component
3010 with cuff fabric 2170 and polymer leaflets 2172 attached to
the bottom sections, but with other possible material layers not
shown. The design of FIGS. 17-19 allows for leaflet attachment to a
single, solid, independent post 3264 in each commissure region, and
with apertures 3266 for suture attachment.
[0090] FIG. 20 shows the primary (tubular or hollow cylindrical)
metal component 4010 of yet another illustrative embodiment of a
prosthetic heart valve in accordance with the invention. Elements
in FIG. 20 that are generally similar to previously described
elements have reference numbers in FIG. 20 that are increased by
1000, 2000, 3000, or 4000 from the reference numbers previously
used for the similar elements. Again, to simplify the depiction,
FIG. 20 shows component 4010 cut axially along its length and then
flattened, but otherwise in the condition that it has when it is
annularly compressed or collapsed. The serpentine shape 4282 of the
support struts or linking members 4280 allows for greater flexure
and/or extension of the structure between ring portion 4100 and
stent portion 4200. This aids in the flexibility of component 4010
within a catheter bending along a tortuous path. It also allows for
conformance to bending when this portion of the implanted valve is
placed in the ascending aorta where it begins to arch. It also
helps to accommodate pulsatile expansion/contraction of the aorta.
Shapes 4282 are serpentine by virtue of undulation in directions
that are annular of the valve as one proceeds along those shapes in
the axial direction (i.e., from element 4100 to element 4200 or
vice versa, which could also be described as parallel to the axis
of blood flow through the finished and implanted valve).
[0091] FIG. 21 shows the primary (tubular or hollow cylindrical)
metal component 5010 of still another illustrative embodiment of a
prosthetic heart valve in accordance with the invention. FIG. 21 is
the same general kind of drawing as FIG. 20. Again, reference
numbers are increased by multiples of 1000 for generally similar
features from earlier-described embodiments. FIG. 21 illustrates
the point that ring portion 5100 may be connected to stent portion
5200 by more than two strut members 5130 adjacent each commissure
post 5264. In particular, in this embodiment there are four
side-by-side struts 5130 adjacent each commissure post 5264. FIG.
21 also shows an example of a structure in which H2 is about 50% of
H1 (generally analogous to the parameters H1 and H2 earlier in this
specification). In this type of embodiment H1 is the approximate
overall height of a solid commissure post 5264, and H2 is the
distance from the top of a commissure post 5264 to the highest
connection between the commissure post and a link 5130 to ring
portion 5100. FIG. 21 also shows other variations from earlier
embodiments, which variations will be self-explanatory from what
has already been said.
[0092] FIG. 22 is similar to FIG. 21 for yet another illustrative
embodiment 6010. In FIG. 22 there are six or eight links 6130
(depending on where the count is taken) between ring portion 6100
and stent portion 6200 adjacent each of solid commissure posts
6264. Nevertheless, this design still has large coronary openings
6140, as is the case for all of the other designs herein. FIG. 22
also illustrates a case in which H2 is approximately 75% of H1, as
those parameters are defined in the preceding paragraph. FIG. 22
still further illustrates the provision of eyelets 6175 on aortic
ring portion 6100 and eyelets 6275 near the base of each stent post
that can be used for such purposes as material (like 300, 700,
and/or 8300 elsewhere in this specification) attachment and/or
releasable attachment of the valve to delivery apparatus.
[0093] FIG. 23 is similar to FIG. 22 for still another illustrative
embodiment 7010. In FIG. 23 there are again four links 7130 between
ring portion 7100 and stent portion 7200 adjacent each of solid
commissure posts 7264. FIG. 23 also illustrates another case in
which H2 is nearly 75% of H1, as those parameters are defined in
earlier paragraphs.
[0094] FIG. 24 shows the structure from FIG. 23 in its
circumferentially expanded condition or state.
[0095] FIG. 25 shows the foreground portion of another illustrative
embodiment 8010 in its annularly or circumferentially expanded
state or condition. Elements that are generally similar to elements
from earlier embodiments have reference numbers that differ by
multiples of 1000 from the reference numbers used for those
elements in earlier embodiments. Although FIG. 25 shows only the
foreground portion of this structure, it will be understood that
this structure continues around behind what is shown in FIG. 25 to
form a full, continuous, uninterrupted ring structure, just as all
of the other embodiments shown herein do. The structure that is
visible in FIG. 25 is basically repeated two more times with equal
angular spacing as one proceeds all the way around the closed ring
structure. As is true for all other embodiments throughout this
specification, a prosthetic heart valve that includes structure
8010 is circumferentially collapsible for less invasive delivery
into a patient, and then re-expandable (e.g., to the size and shape
shown in FIG. 24) when inside the patient at the prosthetic valve
implant site in the patient.
[0096] In the FIG. 25 embodiment, ring portion 8100 includes two
circumferentially extending rows of open-centered,
collapsible/expandable cells. The cells in one of these rows have
reference number 8110a. The cells in the other row have reference
number 8110b. These two rows are partly overlapping in a direction
along a longitudinal axis through the valve (parallel to the
direction of blood flow through the valve after it has been
implanted and is functioning in a patient). Ring portion 8100
expands to a larger circumferential size than stent portion 8200 as
shown in FIG. 25.
[0097] Ring portion 8100 and stent portion 8200 are joined to one
another by six links or struts 8130 extending between those
portions. (Only two of struts 8130 are visible in FIG. 25.) Each
pair of two such struts 8130 is located close to a respective one
of commissure posts 8264 on stent portion 8200. In particular, each
strut 8130 in a given pair is located close to a respective one of
the two sides of the associated commissure post 8264. As described
for other embodiments earlier in this specification, this leaves
relatively large open spaces 8140 in the circumferential direction
between adjacent pairs of the struts. Note that struts 8130 flare
radially outwardly as one proceeds along the struts from the
smaller-circumference stent portion 8200 to the
larger-circumference ring portion 8100.
[0098] Stent portion 8200 includes a single circumferentially
extending row of open-centered, collapsible/expandable cells 8210.
This row of cells 8210 is interrupted by solid commissure posts
8264 at three equally spaced locations around the circumference of
stent portion 8200. Note that the connections of each commissure
post 8264 to the row of cells 8210 are quite low along the overall
length of the commissure post. This gives each commissure post 8264
a relatively long, upper, free end portion, along which the
commissure post does not have any frame connection to any other
portion of valve frame 8010. As in other embodiments considered
elsewhere in this specification, this gives most of the length of
each commissure post 8264 an independent flexing characteristic. By
independent flexing it is meant that the flexing properties of the
post can be relatively independently of the flexing properties of
the rest of frame (especially the rest of stent portion 8200). For
example, each commissure post 8264 can be designed so that its
upper free end portion flexes radially inwardly and then radially
outwardly in response to each opening/closing cycle of the valve
leaflets attached (in part) to that post. The amount of this
flexing can be designed into the relatively independent commissure
posts relatively independently of the amount of stiffness that it
is desired to give the other parts of stent portion 8200 (e.g., for
such purposes as to enable the stent portion as a whole to hold
back native leaflet tissue, to securely anchor the prosthetic valve
in the patient, etc.)
[0099] FIG. 25 shows apertures 8266 that can be provided in each
commissure post 8264 for the purpose of stitching (suturing)
leaflets of the prosthetic valve (and possibly also other layers of
tissue or material) to the commissure posts. In general, it is
stated again that for embodiment 8010 (as for other embodiments
described throughout this specification) flexible leaflets (like
500 in FIGS. 8 and 9 or like 2172 in FIG. 19) can be attached to
stent portion 8200 in the manner generally illustrated elsewhere in
this specification. Similarly, it is again stated that for
embodiment 8010 (as for other embodiments throughout this
specification) other layers of various materials can be attached to
various other portions of frame structure 8010 (e.g., as shown at
300, 400, and 700 in FIGS. 6-9 and at 2170 in FIG. 19).
[0100] Still another feature that FIG. 25 illustrates is the
scalloping of the lower end of stent portion 8200 so that this
lower end or edge is relatively high near the bottom of each
commissure post 8264 (at reference number 8220) and lower at other
locations in the circumferential direction around the valve. This
feature is also a characteristic of other embodiments throughout
this specification, and it can help the implanted prosthetic valve
avoid interfering with other structures in the patient's heart
(e.g., the patient's native mitral valve when the prosthetic valve
is implanted as a replacement aortic valve).
[0101] FIG. 26 shows yet another illustrative embodiment 9010. Once
again, elements that are generally similar to elements from earlier
embodiments have reference numbers that differ by multiples of 1000
from the reference numbers used for those elements in earlier
embodiments. As for all other embodiments herein, a prosthetic
valve that includes structure 9010 is circumferentially collapsible
for less invasive delivery into a patient, and it then re-expands
(e.g., as shown in FIG. 26) when at the implant site in the
patient. As compared, for example, to FIG. 25, embodiment 9010 has
a ring portion 9100 that includes only a single circumferential row
of open-centered, collapsible/expandable cells 9110. The stent
portion 9200 of embodiment 9010 also includes a single
circumferential row of open-centered, collapsible/expandable cells
9210. However, some of these cells have some sides with extra folds
or pleats, which can facilitate giving stent portion 9200 a
different geometry, different stiffness in different locations,
etc. Examples of such extra folds or pleats are identified by
reference numbers 9211a and 9211b. The struts or links 9130 in
embodiment 9010 again have serpentine portions 9282 (like 4282 in
FIG. 20).
[0102] FIG. 27 shows still another illustrative embodiment 10010.
This embodiment has a stent portion 10200 that includes two
circumferentially extending rows of open-centered,
collapsible/expandable cells 10210a and 10210b. These two rows
partly overlap in the axial direction (i.e., in a direction along a
longitudinal axis through the valve). Some of these cells have
extra folds or pleats 10211a, 10211b (like 9211a and 9211b in FIG.
26) for reasons similar to what is described above in connection
with FIG. 26. The ring portion 10100 of structure 10010 is a single
serpentine ring (no open-centered, closed-perimeter cells as in
some other embodiments). There are four struts 10130 adjacent each
of commissure posts 10264 for connecting ring portion 10100 and
stent portion 10200. FIG. 27 is therefore similar to FIGS. 21 and
23 in this respect. Between each group of four struts 10130, stent
portion 10200 includes some extra cells 10213 that extend toward
ring portion 10100. These structures 10213 can help to hold back
native leaflet tissue of the valve that is being replaced by the
prosthetic valve and/or to help anchor the prosthetic valve by
hooking over the upper edge of the leaflets of the patient's native
heart valve.
[0103] FIG. 28 and several subsequent FIGS. provide additional
information as to how valves in accordance with this invention may
be constructed. FIG. 28 is a greatly simplified view looking down
on the stent portion 8200 of valve frame embodiment 8010 before any
other elements have been added to the valve frame. Embodiment 8010
is selected for use in FIG. 28 and subsequent FIGS. solely as an
example. Other frame embodiments shown elsewhere herein can be used
instead if desired. FIG. 28 shows that stent portion 8200 forms a
closed ring, with commissure posts 8264a-c spaced equally from one
another around the ring and connected to one another by the
inter-commissure row or rows of collapsible/expandable cells 8210.
FIG. 28 shows this structure in its circumferentially expanded
condition. In embodiments of this general type, all of the
circumferential collapse and re-expansion of the valve is provided
by cellular structure(s) like 8210 (or in some embodiments,
serpentine structure(s)). Commissure posts 8264 are "solid" and
therefore not themselves (individually) circumferentially
collapsible or re-expandable.
[0104] FIG. 29 shows the addition of one or more layers of
flexible, web-like or sheet-like material annularly around the
inside and/or outside of stent portion 8200. For convenience
herein, all of such sheet material may be referred to by the
general reference number 8300. In the particular example shown in
FIG. 29, sheet material on the outside of stent portion 8200 has
reference number 8300a and sheet material on the inside of stent
portion 8200 has reference number 8300b. Sheet material 8300 may be
like any of earlier described material(s) 300, 400, 700, and/or
2170. See also FIG. 32, which shows by dotted lines 8300 the upper
and lower edges or limits of the sheet material on stent portion
8200 (now shown flat and only in part). Sheet material 8300 may not
need to be provided over both the inner and outer surfaces of stent
portion 8200, but that is one preferred arrangement. Sheet material
8300 may be secured to stent portion 8200 by sutures that pass
through the sheet material and also through and/or around various
parts of stent portion 8200. Among the important functions of sheet
material 8300 are to help the valve seal the native valve annulus
when the valve is implanted in a patient, and to help provide a
seal between the prosthetic valve leaflets and the stent or annular
portion of the valve.
[0105] Some examples of possible variations of what is described in
the immediately preceding paragraph are shown in FIGS. 33 and 34.
FIG. 33 shows an illustrative embodiment with two layers of sheet
material 8300b and 8300c inside stent structure 8210/8264. In such
an embodiment, inner-most layer 8300c may be adapted for buffering
and sealing of the flow of blood (especially in the pockets that
are formed by leaflets 500 in the interior of the valve). Thus, for
example, inner-most layer 8300c may be made of tissue. Outer layer
8300b may be adapted for sealing with the patient's native anatomy
and/or tissue in-growth from that anatomy. Outer layer 8300b may
therefore be made of a fabric material.
[0106] FIG. 34 shows an illustrative embodiment with only one layer
of sheet material 8300b inside stent structure 8210/8264.
[0107] FIG. 30 shows addition of three, flexible, prosthetic valve
leaflets 500a c to the FIG. 29 structure. A representative one of
these leaflets, prior to incorporation into the prosthetic valve,
is shown by itself in FIG. 31. As shown in FIG. 31, each leaflet
500 may start as a flat sheet. The upper straight or relatively
straight edge 510 of this sheet becomes the free edge of the
leaflet when the leaflet is assembled in the prosthetic valve. Two
approximately straight, upper, side edge portions 520a b of the
leaflet can be attached, respectively, to two of the commissure
posts 8264 of the prosthetic valve. The arcuate lower edge portion
530 of the leaflet can be attached (at least partly) to material
8300 between the immediately above-mentioned two commissure posts
8264. All of reference numbers 510, 520, and 530 are shown in FIG.
30 for a representative one of the leaflets, but to avoid
over-complicating that FIG., only reference numbers 510 and 530 are
shown for the two other leaflets.
[0108] FIG. 35 shows an alternative embodiment in which the lower
edge 530 of leaflet 500 arches up rather than down as in FIG. 31.
FIG. 36 shows another alternative embodiment in which the lower
edge 530 of leaflet 500 is approximately straight across. The
leaflet shape that is chosen depends on the operational
characteristics it is desired to achieve. For convenience, the edge
portion 530 that is generally opposite free edge 510 may sometimes
be referred to as the secured edge portion of the leaflet.
[0109] FIG. 30 shows the valve in the closed condition. The "free"
upper edges 510 of the three leaflets 500a c come together in
approximately a Y shape in the interior of the valve to provide a
fluid seal between the leaflets. The side edges 520a b and the
lower edge 530 of each leaflet are secured to the annular structure
8200/8300 of the valve in a way that provides a seal between each
leaflet and the adjacent portion of the annular structure. For
example, this may be accomplished by stitching (suturing) edges 520
and 530 of each leaflet to the annular structure as illustrated by
FIG. 32. In that FIG., "x" marks 540 are used to indicate where
side edge portions 520 of a typical leaflet 500 may be stitched
(sutured) to cantilevered free end portions of commissure posts
8264 (e.g., through commissure post apertures 8266 (FIG. 25)). This
stitching may additionally pass through material 8300. But even if
there is material 8300 between a leaflet 500 and a commissure post
8264, the stitching 540 is preferably directly (straight) through
the leaflet and through or to the commissure post so that the
stitching 540 can apply force from the leaflet directly to the
commissure post. Also in FIG. 32, "o" marks 550 are used to
indicate where the bottom edge of a typical leaflet 500 may be
stitched at least in part to the material 8300 that spans the
open-cellular, inter-commissure structure 8210 of stent portion
8200 (between commissure posts 8264). The net result of all of this
construction is to seal the entire side and lower perimeter 520/530
of each leaflet 500 to the annular structure 8200/8300 of the
valve, while leaving the upper edges 510 of the leaflets with
sufficient slack to come together (as shown in FIG. 30) to close
the valve (or to move apart to open the valve).
[0110] The above-described continuous seal of leaflets 500 to the
annular structure (especially 8300) is effectively continued (by
continuous annular web material 8300) to the native valve annulus
by stent portion 8200 pressing sheet material 8300 radially
outwardly into annular sealing contact or engagement with the
native valve annulus.
[0111] Continuous sheet material 8300 provides many more places 550
where the lower edges of leaflets 500 can be stitched to annular
structure 8200/8300 than would be provided by relatively widely
spaced frame elements 8210 alone. This improves sealing between the
leaflets and the annular structure. (Some of stitches 550 may also
directly embrace (e.g., wrap around) elements of frame structure
8210. But others of stitches 550 typically pass through only a
leaflet 500 and sheet material 8300.) Similarly, the continuous
nature of sheet material 8300 improves sealing between annular
structure 8200/8300 and the patient's native valve annulus. On the
other hand, being able to secure (suture/stitch) the upper side
edges 520 of each leaflet 500 substantially directly to commissure
posts 8264 (e.g., at locations 540) is desirable because these
upper portions of the leaflet may tend to try to pull away from
annular structure 8200/8300 as the valve opens and closes.
Therefore, strong and relatively direct leaflet-to-commissure-post
attachment at points 540 is desirable to absorb this cyclical
tension at the ends of the upper free edge of each leaflet. The
cantilevered, upper, free end portions of commissure posts 8264 can
flex radially in and out in spring-like fashion to absorb the shock
of this cycling leaflet tension and to reduce the maximum amplitude
value that this tension reaches in its cycle. Because the free end
portions of commissure posts 8264 are cantilevered from the rest of
valve frame 8010, these portions of the commissure posts can be
given any desired degree of flexibility or stiffness independent of
the stiffness or flexibility designed into other parts of the valve
frame.
[0112] Note that the prosthetic valve is preferably built up
(constructed) from components that are initially separate as
follows: (1) frame 8010, (2) sheet material 8300, and (3) leaflets
500. Further note that the order of assembly is typically as
follows: (1) frame 8010 is provided, (2) sheet material 8300 is
added to frame 8010, and (3) leaflets 500 are added inside the
assembly of elements 8010 and 8300. Amplifying this last point
somewhat, the three leaflets 500 may be stitched together
side-edge-to-side-edge prior to immediately above-mentioned step
(3). Then above-mentioned step (3) may include (a) dropping the
assembly of leaflets into place inside annular structure 8200/8300,
(b) suturing the leaflets individually to each commissure post 8264
(e.g., at locations 540), and (c) suturing the belly of each
leaflet to sheet material 8300 (e.g., at locations 550) to form the
actual valve. Those skilled in the art will appreciate that
variations on this are possible. In general, however, it is
typically the case that no valve exists separate from frame
structure 8010, or prior to addition of elements 8300 and 500 to
frame structure 8010.
[0113] Again, it is expressly stated that FIGS. 28-32 and the
immediately above paragraphs refer to frame embodiment 8010 only as
an example, and that these principles are equally applicable to
other embodiments shown and described elsewhere in this
specification.
[0114] To quantify what is meant by valves of this invention being
collapsible and re-expandable, it is preferred that a diameter of a
valve in accordance with this invention be collapsible by at least
about 50% (e.g., from about 20-30 mm when fully expanded to about
10-15 mm when fully collapsed). All of the valves shown herein are
capable of collapsing by amounts typified by what is said in the
immediately preceding sentence. More preferably, the percentage of
such diameter reduction when the valve is collapsed is in the range
from about 60% to about 80% (e.g., to about 5-10 mm for a 25 mm
expanded valve). At least the valves shown in the FIGS. from FIG.
12 to the end are capable of collapsing by amounts typified by what
is said in the immediately preceding sentence. Note that a 60%
diameter reduction means that the diameter of the collapsed valve
is 40% of the diameter of the expanded valve. An 80% diameter
reduction means that the diameter of the collapsed valve is 20% of
the diameter of the expanded valve.
[0115] From the foregoing it will be appreciated that the valves of
this invention can be reduced in circumferential size (e.g., for
less invasive delivery of the valve into a patient) and then
re-expanded to full (or normal) circumferential size at the
valve-implant site in the patient. The valves of this invention
typically change circumference in this way without otherwise
radically changing in shape. Reduction in circumference may be
accompanied by a temporary increase in length of the valve. Also, a
skirt like 240, 1240, etc., that is resiliently biased to deflect
radially out may be temporarily deflected in. But the tubular or
cylindrical outer periphery of the valve (e.g., structure 10, 1010,
2010, 3010, or 4010) preferably always remains tubular or
cylindrical. It preferably does not undergo any radical shape
change such as would be involved if it were folded, creased, or
wound along the length (blood flow axis) of the valve. The
circumference of the valve is reduced by compression of component
10, 1010, etc., in the annular or circumferential direction, which
leaves component 10, 1010, etc., a tube of the same basic shape
(although of different size) at all times. This type of reduction
of the circumferential size of component 10, 1010, etc., (and
therefore the remainder of the valve structure), and which does not
rely on folding of component 10, 1010, etc., along its length or
winding of that component about a longitudinal axis, may be
referred to herein as annular or circumferential collapsing,
compression, shrinking, reduction, or the like.
[0116] In the above discussion it is said that ring 100, 1100,
2100, etc., is connected to stent 200, 1200, 2200, etc.,
substantially solely by strut structures 280, 1280, 2280, etc.,
that are adjacent to the commissure posts or tips 236, 1236, 2236,
etc. A purpose of this is to leave relatively large openings 140,
1140, 2140, etc. between annularly adjacent pairs of the strut
structures. To quantify what is meant by the phrase adjacent to the
commissure posts in this context, it can be said that in any given
valve, openings 140, 1140, 2140, etc. collectively (preferably)
constitute about two-thirds (or an even larger fraction) of the
distance in the annular direction around the valve at the height of
the commissure tips when the valve is expanded. Thus, for example,
in the first-described embodiment, W1 (FIG. 3) is the width of one
representative opening 140 at the level of commissure tips 236. W2
is the width of one representative strut structure 130, etc., at
that same level. The sum of dimension W1 for all three openings 140
is at least two-thirds the circumference of the fully expanded
valve at the level of the commissure tips. The sum of dimension W2
for all three strut structures is less than one-third that valve
circumference. This means that the components of each strut
structure are relatively close to the adjacent commissure post or
tip.
[0117] It will be understood that the foregoing is only
illustrative of the principles of this invention, and that various
modifications can be made by those skilled in the art without
departing from the scope and spirit of the invention. For example,
the number and shapes of the various cells (like 110 and 210) in
component 10 or the like can be different from the number and
shapes of the cells shown in the FIGS. herein. Similarly, the
number of undulations in serpentine structures such as 1160a,
1160b, 1162, or the like can be different from the numbers shown in
the FIGS. herein.
* * * * *