U.S. patent application number 15/613688 was filed with the patent office on 2017-09-21 for leaflet attachment for function in various shapes and sizes.
This patent application is currently assigned to St. Jude Medical, Cardiology Division, Inc.. The applicant listed for this patent is St. Jude Medical, Cardiology Division, Inc.. Invention is credited to Peter N. Braido, Jacob John Daly, Julia Ann Schraut.
Application Number | 20170266000 15/613688 |
Document ID | / |
Family ID | 49778898 |
Filed Date | 2017-09-21 |
United States Patent
Application |
20170266000 |
Kind Code |
A1 |
Braido; Peter N. ; et
al. |
September 21, 2017 |
LEAFLET ATTACHMENT FOR FUNCTION IN VARIOUS SHAPES AND SIZES
Abstract
A prosthetic heart valve includes a collapsible and expandable
stent and a plurality of commissure features disposed on the stent.
A collapsible and expandable valve assembly includes a plurality of
leaflets connected to the plurality of commissure features, each
commissure feature including a body having a proximal end and a
distal end. A plurality of eyelets is arranged in rows and columns
on the body for distributing load from the plurality of
leaflets.
Inventors: |
Braido; Peter N.; (Wyoming,
MN) ; Daly; Jacob John; (Blaine, MN) ;
Schraut; Julia Ann; (Shoreview, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
St. Jude Medical, Cardiology Division, Inc. |
St. Paul |
MN |
US |
|
|
Assignee: |
St. Jude Medical, Cardiology
Division, Inc.
St. Paul
MN
|
Family ID: |
49778898 |
Appl. No.: |
15/613688 |
Filed: |
June 5, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15202939 |
Jul 6, 2016 |
9693861 |
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15613688 |
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14824551 |
Aug 12, 2015 |
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15202939 |
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13781201 |
Feb 28, 2013 |
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14824551 |
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61666224 |
Jun 29, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/2418 20130101;
A61F 2/2412 20130101; A61F 2220/0075 20130101; A61F 2230/0054
20130101; A61F 2230/0069 20130101; A61F 2/2409 20130101; A61F
2230/0067 20130101; A61F 2220/005 20130101 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. (canceled)
2. A prosthetic heart valve, comprising: a collapsible and
expandable stent having an inflow end and an outflow end, the stent
including a plurality of commissure attachment features and a
plurality of struts defining a plurality of cells, and the stent
extending in a length direction from the inflow end to the outflow
end; and a collapsible and expandable valve assembly including a
plurality of leaflets connected to the plurality of commissure
attachment features; wherein each leaflet includes a first edge
operably coupled to the stent, a second free edge, a first tab
connecting a first end of the first edge to a first end of the
second free edge, and a second tab connecting a second end of the
first edge to a second end of the second free edge, each of the
first and second tabs being folded over a reinforcement material
about a fold line in the tab.
3. The prosthetic heart valve of claim 2, wherein the reinforcement
material is fabric or a polymer sheet material.
4. The prosthetic heart valve of claim 2, wherein the reinforcement
material is tissue.
5. The prosthetic heart valve of claim 2, wherein each tab is
attached to the corresponding reinforcement material by at least
one suture.
6. The prosthetic heart valve of claim 2, wherein each tab is
attached to a corresponding commissure attachment feature.
7. A prosthetic heart valve, comprising: a collapsible and
expandable stent having an inflow end and an outflow end, the stent
including a plurality of commissure attachment features and a
plurality of struts defining a plurality of cells, and the stent
extending in a length direction from the inflow end to the outflow
end; and a collapsible and expandable valve assembly including a
plurality of leaflets connected to the plurality of commissure
attachment features; wherein each leaflet includes a first edge
operably coupled to the stent, a second free edge, a first tab
connecting a first end of the first edge to a first end of the
second free edge, the first tab being rectangular and being
foldable about a first fold line and having a first height in the
length direction, a first flap extending in a circumferential
direction from the first tab and being foldable about a second fold
line, the first flap having a second height in the length direction
less than the first height.
8. The prosthetic heart valve of claim 7, wherein the first flap is
rectangular.
9. The prosthetic heart valve of claim 7, wherein a top edge of the
first tab is aligned with a top edge of the first flap.
10. The prosthetic heart valve of claim 7, wherein the first tab is
integral with the first flap.
11. The prosthetic heart valve of claim 7, wherein the first tab is
non-integral with the first flap, the first tab being attached to
the first flap.
12. The prosthetic heart valve of claim 7, wherein the first tab
and the first flap are formed of the same material.
13. The prosthetic heart valve of claim 7, wherein the first tab
and the first flap are formed of different materials.
14. The prosthetic heart valve of claim 7, wherein each leaflet
further includes a second tab connecting a second end of the first
edge to a second end of the second free edge, the second tab being
rectangular and being foldable about a third fold line and having a
third height in the length direction, a second flap extending in a
circumferential direction from the second tab and being foldable
about a fourth fold line, the second flap having a fourth height in
the length direction less than the third height.
15. A prosthetic heart valve, comprising: a collapsible and
expandable stent having an inflow end and an outflow end, the stent
including a plurality of commissure attachment features and a
plurality of struts defining a plurality of cells, and the stent
extending in a length direction from the inflow end to the outflow
end; and a collapsible and expandable valve assembly including a
plurality of leaflets connected to the plurality of commissure
attachment features; wherein each leaflet includes a first edge
operably coupled to the stent, a second free edge, a first tab
connecting a first end of the first edge to a first end of the
second free edge, the first tab being rectangular and being
foldable about a first fold line extending in the length direction,
a first flap extending in the length direction from the first tab
and being foldable about a second fold line extending in a
circumferential direction transverse the length direction.
16. The prosthetic heart valve of claim 15, wherein the first flap
is rectangular.
17. The prosthetic heart valve of claim 15, wherein the first tab
and the first flap are formed of the same material.
18. The prosthetic heart valve of claim 15, wherein the first tab
and the first flap are formed of different materials.
19. The prosthetic heart valve of claim 15, further comprising a
second flap extending in the length direction and foldable about a
second fold line extending in the circumferential direction.
20. The prosthetic heart valve of claim 19, wherein the second flap
is coupled to leaflet at a juncture between a second end of the
first edge of the leaflet and a second end of the second free edge
of the leaflet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 15/202,939 filed Jul. 6, 2016, which is a
continuation of U.S. patent application Ser. No. 14/824,551 filed
on Aug. 12, 2015, which is a continuation of U.S. patent
application Ser. No. 13/781,201 filed on Feb. 28, 2013, which
claims the benefit of the filing date of U.S. Provisional Patent
Application No. 61/666,224 filed Jun. 29, 2012, the disclosures of
which are all hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to heart valve replacement
and, in particular, to collapsible prosthetic heart valves. More
particularly, the present invention relates to collapsible
prosthetic heart valves that may be repositioned during a
deployment procedure.
[0003] Prosthetic heart valves that are collapsible to a relatively
small circumferential size can be delivered into a patient less
invasively than valves that are not collapsible. For example, a
collapsible valve may be delivered into a patient via a tube-like
delivery apparatus such as a catheter, a trocar, a laparoscopic
instrument, or the like. This collapsibility can avoid the need for
a more invasive procedure such as full open-chest, open-heart
surgery.
[0004] Collapsible prosthetic heart valves typically take the form
of a valve structure mounted on a stent. There are two types of
stents on which the valve structures are ordinarily mounted: a
self-expanding stent and a balloon-expandable stent. To place such
valves into a delivery apparatus and ultimately into a patient, the
valve must first be collapsed or crimped to reduce its
circumferential size.
[0005] When a collapsed prosthetic valve has reached the desired
implant site in the patient (e.g., at or near the annulus of the
patient's heart valve that is to be replaced by the prosthetic
valve), the prosthetic valve can be deployed or released from the
delivery apparatus and re-expanded to full operating size. For
balloon-expandable valves, this generally involves releasing the
entire valve, assuring its proper location, and then expanding a
balloon positioned within the valve stent. For self-expanding
valves, on the other hand, the stent automatically expands as the
sheath covering the valve is withdrawn.
[0006] In delivery systems for self-expanding aortic valves, after
the delivery system has been positioned for deployment, the annulus
end of the valve may be unsheathed and expanded first, while the
aortic end of the valve remains sheathed. Once the annulus end of
the valve has expanded, it may be determined that the valve needs
to be repositioned in the patient's aortic annulus. To accomplish
this, a user (such as a surgeon or an interventional cardiologist)
typically resheaths the annulus end of the valve, so that the valve
can be repositioned while in a collapsed state. After the valve has
been repositioned, the user can fully deploy the valve.
[0007] Once a self-expanding valve has been fully deployed, it
expands to a diameter larger than that of the sheath that
previously contained the valve in the collapsed condition, making
resheathing impossible, or difficult at best. In order for the user
to be able to more readily resheath a valve, it is preferable that
the position and operation of the valve be evaluated after the
valve has been only partially deployed, with a portion of the valve
still collapsed inside of the sheath.
[0008] Despite the various improvements that have been made to
collapsible prosthetic heart valves, conventional devices, suffer
from some shortcomings. For example, in certain procedures,
collapsible valves may be implanted in a native valve annulus
without first resecting the native valve leaflets. The collapsible
valves may have critical clinical issues because of the nature of
the stenotic leaflets that are left in place. Additionally,
patients with uneven calcification, bi-cuspid disease, and/or valve
insufficiency could not be treated well, if at all, with the
current collapsible designs.
[0009] The reliance on evenly calcified leaflets could lead to
several problems such as: (1) perivalvular leakage (PV leak), (2)
valve migration, (3) mitral valve impingement, (4) conduction
system disruption, (5) coronary blockage, etc., all of which can
have severely adverse clinical outcomes. To reduce these adverse
events, the optimal valve would seal and anchor adequately without
the need for excessive radial force, protrusion into the left
ventricular outflow tract (LVOT), etc., that could harm nearby
anatomy and physiology.
[0010] There therefore is a need for further improvements to the
devices and systems of collapsible prosthetic heart valves, and in
particular, self-expanding prosthetic heart valves. Among other
advantages, the present invention may address one or more of these
needs.
SUMMARY OF THE INVENTION
[0011] In some embodiments, a prosthetic heart valve includes 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 heart valve further includes a
plurality of commissure features disposed on the stent and a
collapsible and expandable valve assembly, the valve assembly
including a plurality of leaflets connected to the plurality of
commissure features. Each commissure feature includes a body having
a proximal end a distal end, and a plurality of eyelets arranged in
at least two rows and at least two columns for distributing load
from the plurality of leaflets.
[0012] In some examples, each of the plurality of commissure
features includes a body that is substantially rectangular.
Additionally, each of the plurality of commissure features may
include at least three rows of eyelets disposed on the body. Each
of the plurality of commissure features may include two columns of
eyelets disposed on the body. Each of the plurality of eyelets may
be substantially the same shape and/or size.
[0013] In some embodiments, a prosthetic valve assembly for
assembly to a collapsible and expandable stent includes a stent
having a plurality of commissure features, each commissure feature
including a body having a longitudinal direction extending between
a proximal end and a distal end, and a plurality of eyelets
arranged in a plurality of columns each extending in the
longitudinal direction, the body having a width in a direction
orthogonal to the longitudinal direction. The valve assembly may
include a plurality of leaflets, each leaflet having a top free
edge for coapting with others of the leaflets and including at
least one rectangular tab foldable upon itself along a fold line
for attaching to a commissure feature at a leaflet-commissure
feature junction, the at least one rectangular tab having a width
which is at least as long as the width of the body.
[0014] In some examples, the tab includes a distal end extending
beyond the distal end of the body when the tab is aligned for
attachment to the commissure feature. A flap may be coupled to one
side of the tab to provide an additional buffer at the
leaflet-commissure feature junction.
[0015] In some embodiments a prosthetic heart valve includes 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. A plurality of commissure features
may be disposed on the stent, each commissure feature including a
body having a longitudinal direction extending between a proximal
end and a distal end, and a plurality of eyelets arranged in at
least two columns extending in the longitudinal direction and at
least two rows extending in a direction orthogonal to the
longitudinal direction, for distributing load from the plurality of
leaflets. A collapsible and expandable valve assembly may include a
plurality of leaflets connected to the plurality of commissure
features via a suture pattern. The plurality of eyelets may be
arranged in two columns and the suture pattern forms an "X" pattern
between an eyelet in a first of the column and an adjacent eyelet
of a second in the columns.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Various embodiments of the present invention are described
herein with reference to the drawings, wherein:
[0017] FIG. 1 is a partial side elevational view of a prosthetic
heart valve including a valve assembly and a stent;
[0018] FIG. 2A is an end view of a prosthetic heart valve as seen
from the aortic sinus toward the heart and the native valve
annulus, the valve having in a circular configuration;
[0019] FIG. 2B is an end view of a prosthetic heart valve as seen
from the aortic sinus toward the heart and the native valve
annulus, the valve having an elliptical configuration;
[0020] FIGS. 3A-C are end views of the prosthetic heart valve of
FIG. 1 in various less than ideal configurations due to anatomical
differences in the native valve morphology from patient to
patient;
[0021] FIG. 4 is a partial side elevational view of the prosthetic
heart valve of FIG. 1 depicting areas of high stress on the valve
assembly;
[0022] FIG. 5A is an enlarged, schematic side view of a commissure
feature of a prosthetic heart valve showing the distribution of
load therein;
[0023] FIG. 5B is an enlarged, schematic side view of a commissure
feature showing the load distribution therein according to one
embodiment of the present invention;
[0024] FIGS. 6A-S are enlarged schematic side views of several
embodiments of commissure features according to the present
invention;
[0025] FIG. 7A is an enlarged, schematic side view of the
commissure feature of FIG. 5A being attached to a leaflet;
[0026] FIG. 7B is an enlarged, schematic side view of the
commissure feature of FIG. 6F being attached to a leaflet;
[0027] FIG. 7C is an enlarged, schematic side view of another
example of a commissure feature according to the present
invention;
[0028] FIG. 8A is an enlarged, schematic side view a conventional
valve leaflet;
[0029] FIG. 8B is an enlarged, schematic side view of a first
embodiment of a valve leaflet according the present invention;
[0030] FIG. 8C is an enlarged, schematic side view of a second
embodiment of a valve leaflet according to the present
invention;
[0031] FIG. 8D is an enlarged, schematic side view of a third
embodiment of a valve leaflet according to the present
invention;
[0032] FIGS. 9A-B are enlarged, schematic side views of a
conventional leaflet and a leaflet according to the present
invention, showing the tab-free edge attachment;
[0033] FIGS. 10A-B are enlarged, schematic side views showing a
suture pattern attaching leaflets to a commissure feature as shown
from the ablumenal side and the lumenal side of the valve,
respectively;
[0034] FIG. 10C is an enlarged, schematic view of FIG. 10A showing
the attachment points of the suture pattern in more detail;
[0035] FIGS. 11A-B are enlarged, schematic side views showing
another suture pattern attaching leaflets to a commissure feature
as shown from the ablumenal side and the lumenal side of the valve
respectively;
[0036] FIGS. 12A-B are enlarged, schematic side views showing a
further suture pattern attaching leaflets to a commissure feature
as shown from the ablumenal side and the lumenal side of the valve
respectively; and
[0037] FIGS. 13A-B are enlarged, schematic side views showing yet
another suture pattern attaching leaflets to a commissure feature
as shown from the ablumenal side and the lumenal side of the valve
respectively.
[0038] Various embodiments of the present invention will now be
described with reference to the appended drawings. It is to be
appreciated that these drawings depict only some embodiments of the
invention and are therefore not to be considered limiting of its
scope.
DETAILED DESCRIPTION OF THE INVENTION
[0039] As used herein, the term "proximal," when used in connection
with a prosthetic heart valve, refers to the end of the heart valve
closest to the heart when the heart valve is implanted in a
patient, whereas the term "distal," when used in connection with a
prosthetic heart valve, refers to the end of the heart valve
farthest from the heart when the heart valve is implanted in a
patient.
[0040] FIG. 1 shows a collapsible prosthetic heart valve 100
according to an embodiment of the present disclosure. The
prosthetic heart valve 100 is designed to replace the function of a
native aortic valve of a patient. Examples of collapsible
prosthetic heart valves are described in International Patent
Application Publication No. WO/2009/042196; U.S. Pat. No.
7,018,406; and U.S. Pat. No. 7,329,278, the disclosures of all of
which are hereby incorporated herein by reference. As discussed in
detail below, the prosthetic heart valve has an expanded condition
and a collapsed condition. Although the invention is described
herein as applied to a prosthetic heart valve for replacing a
native aortic valve, the invention is not so limited, and may be
applied to prosthetic valves for replacing other types of cardiac
valves.
[0041] The prosthetic heart valve 100 includes a stent or frame
102, which may be wholly or partly formed of any biocompatible
material, such as metals, synthetic polymers, or biopolymers
capable of functioning as a stent. Suitable biopolymers include,
but are not limited to, elastin, and mixtures or composites
thereof. Suitable metals include, but are not limited to, cobalt,
titanium, nickel, chromium, stainless steel, and alloys thereof,
including nitinol. Suitable synthetic polymers for use as a stent
include, but are not limited to, thermoplastics, such as
polyolefins, polyesters, polyamides, polysulfones, acrylics,
polyacrylonitriles, polyetheretherketone (PEEK), and polyaramides.
The stent 102 may have an annulus section 110 an aortic section
(not shown) and a transition section (not shown) disposed between
the annulus section and the aortic section. Each of the annulus
section 110, the transition section and the aortic section of the
stent 102 includes a plurality of cells 112 connected to one
another around the stent. The annulus section 110 and the aortic
section of the stent 102 may include one or more annular rows of
cells 112 connected to one another. For instance, the annulus
section 110 may have two annular rows of cells 112. When the
prosthetic heart valve 100 is in the expanded condition, each cell
112 may be substantially diamond shaped. Regardless of its shape,
each cell 112 is formed by a plurality of struts 114. For example,
a cell 112 may be formed by four struts 114.
[0042] The stent 102 may include commissure features 116 connecting
at least two cells 112 in the longitudinal direction of the stent
102. The commissure features 116 may include eyelets for
facilitating the suturing of a valve assembly 104 to the sent
102.
[0043] The prosthetic heart valve 100 also includes a valve
assembly 104 attached inside the annulus section 110 of the stent
102. United States Patent Application Publication No. 2008/0228264,
filed Mar. 12, 2007, and United States Patent Application
Publication No. 2008/0147179, filed Dec. 19, 2007, the entire
disclosures of both of which are hereby incorporated herein by
reference, describe suitable valve assemblies. The valve assembly
104 may be wholly or partly formed of any suitable biological
material or polymer. Examples of biological materials suitable for
the valve assembly 104 include, but are not limited to, porcine or
bovine pericardial tissue. Examples of polymers suitable for the
valve assembly 104 include, but are not limited to, polyurethane
and polyester. In at least some examples, portions of valve
assembly 104, a cuff and the suture used may include an ultra high
molecular weight polyethylene, such as FORCE FIBER.RTM..
[0044] The valve assembly 104 may include a cuff 106 disposed on
the lumenal surface of annulus section 110, on the ablumenal
surface of annulus section 110, or on both surfaces, and the cuff
may cover all or part of either or both of the lumenal and
ablumenal surfaces of the annulus section. The cuff 106 and/or the
sutures used to attach the valve assembly 104 to stent 102 may be
formed from or include ultra-high-molecular-weight polyethylene.
FIG. 1 shows cuff 106 disposed on the lumenal surface of annulus
section 110 so as to cover part of the annulus section while
leaving another part thereof uncovered. The cuff 106 may be
attached to stent 102 by one or more strings or sutures passing
through the cuff and around selected struts 114 of the stent. The
valve assembly 104 may further include a plurality of leaflets 108
which collectively function as a one-way valve. A first edge 122 of
each leaflet 108 may be attached to the stent 102 between two
adjacent commissure features 116 by any suitable attachment means,
such as suturing, stapling, adhesives, laser, heat or ultrasonic
bonding or the like. For example, the first edge 122 of each
leaflet 108 may be sutured to the stent 102 by passing strings or
sutures through the cuff 106 of the valve assembly 104. The
leaflets 108 may be attached to the stent 102 along at least some
struts 114 of the stent and through the eyelets in the commissure
features 116 to enhance the structural integrity of the valve
assembly 104. A second or free edge 124 of each leaflet 108 may
coapt with the corresponding free edges of the other leaflets,
thereby enabling the leaflets to function collectively as a one-way
valve.
[0045] As shown in FIG. 1, at least one leaflet 108 may be attached
to the stent 102 so that its first edge 122 is disposed
substantially along specific struts 114a, 114b, 114c, 114d, 114e
and 114f located in the annulus section 110 of the stent. That is,
the edge 122 is positioned in substantial alignment with struts
114a, 114b, 114c, 114d, 114e, and 114f. Struts 114a, 114b, and 114c
may be connected to one another in substantially end-to-end fashion
diagonally along three cells 112, beginning with an end of the
strut 114a connected to a commissure feature 116 and ending with an
end of strut 114c connected to an end of strut 114d. Struts 114c
and 114d are part of the same cell 112 and may collectively define
a substantially right angle between them. Struts 114d, 114e, and
114f may be connected to one another in substantially end-to-end
fashion diagonally along three cells 112, beginning with an end of
the strut 114f connected to a commissure feature 116 and ending
with the connection between an end of strut 114c and an end of
strut 114d.
[0046] As discussed above, the leaflets 108 may be attached
directly to and supported by the struts 114a, 114b, 114c, 114d,
114e, and 114f, and by commissure features 116, such as by
suturing. In such event, the cuff 106 may perform little or no
supportive function for the leaflets 108. Hence, the cuff 106 is
not subjected to high stresses and is therefore less likely to wear
during use. In light of this, the thickness of the cuff may be
reduced. Reducing the thickness of the cuff 106 results in a
decrease in the volume of the valve assembly 104 in the collapsed
condition. This decreased volume is desirable as it enables the
prosthetic heart valve 100 to be implanted in a patient using a
delivery device that is smaller in cross-section than conventional
delivery devices. In addition, since the material forming the stent
struts 114 is stronger than the material forming the cuff 106, the
stent struts 114 may perform the supportive function for the
leaflets 108 better than the cuff 106.
[0047] The volume of the valve assembly 104 may be further reduced
by having the cuff 106 cover only a portion of the surface of
annulus section 110. With continued reference to FIG. 1, the first
or proximal end 118 of the cuff 106 may substantially follow the
contour of the first or proximal end 119 of the stent 102. As such,
the proximal end of the cuff 106 may have a generally sinusoidal or
zigzag shape. This eliminates any free edge of the cuff 106, which
otherwise might extend directly between the cusps of the cells 112
at the proximal end 119 of the stent 102, and enables the entire
length of the proximal end 118 of the cuff 106 to be secured to the
stent 102. The second or distal end 120 of the cuff 106, on the
other hand, may be disposed substantially along at least some
struts 114, but not necessarily the struts in a single annular row
of cells 112. More particularly, the distal end 120 of the cuff 106
may follow the stent struts 114 up to the commissure features 116,
such that the cuff covers all of the cells 112 in the bottom
annular row 113 of cells and in a second annular row 115 of cells
located between the commissure features and the proximal end 119 of
the stent 102, but covers a lesser area of cells in the annular
regions between the commissure features. In other words, the distal
end 120 of the cuff 106 may be disposed substantially along struts
114a, 114b, 114e, 114f, 114g and 114h, as shown in FIG. 1. Strut
114g may be connected at one end to strut 114h, and at the other
end to the intersection of struts 114b and 114c. Strut 114h may be
connected at one end to strut 114g, and at the other end to the
intersection of struts 114d and 114e. Struts 114c, 114d, 114g, and
114h collectively form a single cell 112.
[0048] As a result of the foregoing configuration, all of the cells
112 in the bottom annular row 113 of cells may be entirely covered
by the cuff 106. The cuff 106 may also entirely cover those cells
112 in the second annular row 115 that are located directly below
the commissure features 116. All of the other cells 112 in the
stent 102 may be open or not covered by the cuff 106. Hence, there
may be no cells 112 which are only partially covered by the cuff
106.
[0049] Since the edges of the valve leaflets 108 extend up to the
second annular row 115 of cells 112 only in the regions of the
commissure features 116, there is little to no likelihood of
leakage in the area of the cells between the commissure features in
the second annular row of cells, and therefore no need for the cuff
106 to cover this area. This reduction in the area of the cuff 106,
both at the proximal end 118 and at the distal end 120 thereof,
reduces the amount of material in the valve assembly 104, thereby
enabling the prosthetic valve 100 to achieve a smaller
cross-section in the collapsed condition.
[0050] In operation, the embodiments of the prosthetic heart valve
100 described above may be used to replace a native heart valve,
such as the aortic valve, a surgical heart valve or a heart valve
that has undergone a surgical procedure. The prosthetic heart valve
may be delivered to the desired site (e.g., near a native aortic
annulus) using any suitable delivery device. During delivery, the
prosthetic heart valve is disposed inside the delivery device in
the collapsed condition. The delivery device may be introduced into
a patient using a transfemoral, transapical, transseptal,
tranxaxillary or other approach. Once the delivery device has
reached the target site, the user may deploy the prosthetic heart
valve. Upon deployment, the prosthetic heart valve expands into
secure engagement within the native aortic annulus. When the
prosthetic heart valve is properly positioned inside the heart, it
works as a one-way valve, allowing blood to flow in one direction
and preventing blood from flowing in the opposite direction.
[0051] In certain procedures, collapsible valves may be implanted
in a native valve annulus without first resecting the native valve
leaflets. The collapsible valves may have critical clinical issues
because of the nature of the stenotic leaflets that are left in
place. Additionally, patients with uneven calcification, bi-cuspid
aortic valve disease, and/or valve insufficiency could not be
treated well, if at all, with the current collapsible designs.
[0052] The reliance on evenly calcified leaflets could lead to
several problems such as: (1) perivalvular leakage (PV leak), (2)
valve migration, (3) mitral valve impingement, (4) conduction
system disruption, (5) coronary blockage, etc., all of which can
have severely adverse clinical outcomes. To reduce these adverse
events, the optimal valve would seal and anchor adequately without
the need for excessive radial force, protrusion into the left
ventricular outflow tract (LVOT), etc., that could harm nearby
anatomy and physiology.
[0053] FIGS. 2A and 2B show an end view of a prosthetic heart valve
200 as seen from the outflow or downstream side of the valve
assembly, e.g., looking from the aorta or aortic sinus toward the
heart and the native valve annulus. As seen in FIG. 2A, the valve
assembly includes a stent 202 and valve leaflets 208a, 208b, and
208c attached to the stent and to commissure features 216a, 216b,
and 216c. At least one edge of each leaflet 208 is sutured to the
stent 202 and to two of the three commissure features 216, leaving
at least one edge free to move in response to the pumping of blood.
As the blood pressure in the left ventricle increases, the free
edges of the leaflets move away from one another to allow blood to
flow from the left ventricle to the aorta, following which the free
edges move toward one another and coapt to prevent blood from
flowing back from the aorta into the left ventricle.
[0054] It will be understood that the coaptation of "the free
edges" of the valve leaflets does not necessarily mean that the
actual edges meet per se. Indeed, the leaflets are preferably
sized, shaped, and attached such that a suitable "belly" contour is
formed. And the leaflets should each include a portion extending
from the free edge toward the annulus (referred to herein as a
"coaptation section") that may engage the coaptation sections of
the other leaflets such that there will be a surface area of
contact between the leaflets rather than edge-to-edge contact. This
surface area of contact is important so that, when in a closed or
"coapted" condition, the leaflets cooperate to substantially
prevent backflow or regurgitation of blood through the valve. These
areas of actual contact between the coaptation sections of adjacent
leaflets are referred to herein as the coaptation junctions of the
leaflets and are illustrated in FIG. 2A at 211a, 211b, and 211c.
The coaptation section of each leaflet may range in size as a
particular valve design demands, but generally will be sufficient
to provide some tolerance or ability to form a coaptation junction
even if the shape of the valve is distorted during placement, as
illustrated in FIG. 2B.
[0055] The annulus section of prosthetic heart valve 200 has a
generally regular cylindrical shape by which is meant that the
structure has a generally circular cross-section with a
substantially constant diameter along its length. When placed in
the annulus of a native heart valve, such as, for example, the
tricuspid aortic valve, and expanded, a substantially fluid-tight
fit should result. However, the native valve annulus may not be
circular, and, in fact, may vary from patient to patient, as may
the shape of the aortic sinus or aorta, the angle of the junction
between the valve annulus and the aortic sinus, and other local
anatomical features. When prosthetic heart valve 200 is deployed
and expanded, it must accommodate these anatomical variations in
order to function properly. This may result in a distortion in the
shape of stent 202 and/or valve assembly 204, and the repositioning
of leaflets 208a, 208b, and 208c relative to one another, which can
affect the coaptation junctions 211a, 211b, and 211c.
[0056] As the stent of a collapsible prosthetic heart valve
distorts during implantation, during beating of the heart, or
because of irregularities in the patient's anatomy or the condition
of the native valve, such distortion may be translated to the valve
assembly, such that not all of the valve leaflets meet to form
effective coaptation junctions. This can result in leakage or
regurgitation and other inefficiencies which can reduce cardiac
performance. Moreover, if the prosthetic valve is not placed
optimally and the valve leaflets are not coapting as intended,
other long term effects, such as uneven wear of the individual
leaflets, can be postulated.
[0057] As shown in FIG. 2B, ideally, valve leaflets 208a, 208b, and
208c fully coapt despite the distortion of the annulus section
(hidden behind the valve leaflets in this figure) into a more
elongated or elliptical configuration. As will be appreciated, the
distortion of the annulus section affects the relative positions of
commissure features 216a-c, as well as the positions of leaflets
208a-c relative to one another. The ability of the valve leaflets
208a-c to fully coapt despite this distortion enables prosthetic
valve 200 to function in the manner intended.
[0058] FIGS. 3A-C illustrate a series of prosthetic heart valve as
seen from the downstream side of the valve assembly, e.g., looking
from the aorta or aortic sinus toward the heart and the native
valve annulus. Each of these valves has an elliptical configuration
resulting from the shape of the native valve annulus, calcification
and possibly other defects. As seen in FIGS. 3A-C, the imperfect
geometry the valve assumes results in inadequate coaptation of the
leaflets 208a-c. Specifically, the leaflets 208 of these valves are
incapable of complete coaptation when disposed in a native valve
annulus with an elliptical, ovoid or otherwise non-circular
configuration. In some examples, a gap 238 may be evident between
the leaflets 208 in what should be the fully closed condition. Such
inadequate coaptation may lead to leakage and regurgitation as
discussed above.
[0059] In addition to inadequate coaptation, less than ideal native
valve geometry may also increase the stresses on certain portions
of the prosthetic heart valve. FIG. 4 is a partial side view of a
prosthetic heart valve 400 having a stent 402 and a valve assembly
404 disposed in the annulus section 410 of the stent. Within the
heart valve 400, leaflets 408 are attached to cuff 406 via sutures.
Specifically, FIG. 4 shows the load distribution in the valve
assembly. When leaflets 408 coapt to form a closed configuration,
load is transferred from the leaflet structure to the
leaflet-commissure feature junction as indicated by "A". The load
distribution diagram shows that high point loads are generated at
region "A" where the leaflets are joined to the commissure feature
416. If the point loads at regions "A" are sufficiently high, the
leaflets may tear from the commissure feature. Thus, regions A may
be prone to failure.
[0060] Features of this aspect of the present invention will be
described in connection with the commissure features shown in FIGS.
5A and 5B. It will also be noted that while the inventions herein
described are predominately discussed in terms of a tricuspid valve
and a stent having a shape as illustrated in FIG. 1, the valve
could be a bicuspid valve, such as the mitral valve, and the stent
could have different shapes, such as a flared or conical annulus
section, a less-bulbous aortic section, and the like, and a
differently shaped transition section.
[0061] FIG. 5A illustrates a previous version of a commissure
feature 500 coupled to struts 514 for attaching a valve assembly to
the stent. Commissure feature 500 is formed of a body 502 having a
pair of eyelets 504. Leaflets (not shown) may be attached via
sutures to commissure feature 500 through eyelets 504 and struts
514. Load is distributed across the area of commissure feature 500
as shown in FIG. 5A. Specifically, stress from the leaflets is
distributed across area L1 of the commissure feature 500.
[0062] FIG. 5B illustrates a commissure feature 600 coupled to
struts 614 according to one embodiment of the present invention.
Commissure feature 600 is formed of a body 602 having a plurality
of eyelets 604 arranged in rows and/or columns. Leaflets (not
shown) may be attached via sutures, glue, staples or any suitable
means to commissure feature 600 through eyelets 604 and struts 614.
Stress from the leaflets is distributed across area L2 of the
commissure feature 600, as shown in FIG. 5B. Details of commissure
feature 600 will be described in greater detail with reference to
FIGS. 6A-J. It will suffice to note at this point that a comparison
of FIGS. 5A and 5B illustrates the difference in the area for load
distribution between commissure features 500 and 600. Specifically,
commissure feature 600 provides a larger area L2 across which the
stress from the leaflets is distributed when compared to area L1 of
commissure features 500. A larger area for distributing loads may
decrease the chance of failure at the commissure feature-leaflet
attachment. Moreover, increasing the spacing between eyelets 604
may allow the valve to function better acutely and chronically. The
benefit of wider-spaced eyelets may be recognized in improved ease
of manufacturing, which in turn generally leads to improved yields
for functional and visual valve criteria. Ease of manufacturing
reduces the likelihood for tolerance stack-ups related to tissue
folding and alignment. This may also reduce need for pinching or
manipulation of the valve during assembly.
[0063] FIGS. 6A-J illustrates several specific embodiments of
commissure features according to the present invention, all of
which have the same general shape and characteristics. It will be
appreciated that the commissure features described in these figures
are exemplary and should not be considered limiting. Moreover, the
described features in the following embodiments may be combined or
modified in any desirable manner.
[0064] FIG. 6A illustrates a commissure feature 600 according to
one embodiment of the present invention. Commissure feature 600
includes a body 602 having a proximal end 610 and a distal end 620,
and a plurality of eyelets 604 disposed therein. Specifically, the
commissure feature 600 of FIG. 6A includes four rows of eyelets 604
along the length of body 602, each row including two eyelets so as
to form two columns of eyelets. The rows of eyelets 604 may be
evenly spaced and of the same shape and size, as illustrated in
FIG. 6A, so as to be symmetrical with respect to a central
longitudinal axis of body 602. As depicted, the eyelets 604 are all
in the shape of similarly sized squares. Body 602 is coupled to
struts 614 at its proximal end 610 and distal end 620. Leaflets
(not shown) may be attached via sutures to commissure feature 600
through eyelets 604.
[0065] FIG. 6B illustrates a second embodiment of commissure
feature 600 which is similar to that of FIG. 6A, with two
exceptions. First, recesses 608 are disposed on the side edges of
the body 602 near the distal end 620. Recesses 608 may be formed as
indentations or depressions in body 602 and sutures may be wrapped
around or disposed within the recesses. Such recesses may be useful
in not only securing and guiding a suture, but also in protecting
the suture from adjacent cells, a delivery system or other
anatomical bodies that may damage it. Second, the plurality of
eyelets 604 are not evenly spaced in FIG. 6B. Though the four rows
of eyelets 604 are evenly spaced in the longitudinal direction,
each of the first three rows of eyelets (beginning at the proximal
end) 610 of body 402 has a pair of eyelets spaced a first distance
from the central axis of the body, while the fourth row has a pair
of eyelets spaced closer to one another and closer to the central
axis of the body. Nonetheless, the pattern of eyelets 604 in this
commissure feature 600 is also symmetrical with respect to the
central longitudinal axis of body 602, the row in which the eyelets
are spaced closer to one another need not be the fourth row, but
may be any row. In addition, the eyelets may be spaced closer to
one another in more than one row. Spacing may depend on leaflet
thickness and where the free edge transitions so as to not pinch
the leaflets too tightly together or abrade the free edge of the
leaflet as it moves.
[0066] Another embodiment of commissure feature 600 is depicted in
FIG. 6C. In this commissure feature, eyelets 604 are not all the
same size. Instead, the first row of eyelets (beginning at the
proximal end 610 of body 602) includes larger square eyelets 604a
and 604b, while the next three rows include smaller, rectangular
eyelets 604c-h. While depicted in the first row, the larger square
eyelets can be in any row, and in more than one row. All four rows
of eyelets may be evenly spaced in the longitudinal direction, and
the pattern of eyelets is symmetrical with respect to the central
longitudinal axis of body 602.
[0067] FIG. 6D illustrates another embodiment of commissure feature
600 including four rows of eyelets 604 having the same shape but
different sizes. The first three rows of eyelets 604 (beginning at
the proximal end 610 of body 602) are all squares of substantially
the same size, while the fourth row has square eyelets 604 of a
smaller size. The row of eyelets having a different size (smaller
or larger) need not be the fourth row, but may be any row.
Moreover, the different-sized eyelets need not be limited to one
row, but may be disposed in any number of rows. Regardless of the
eyelets sizes, the pattern of eyelets 604 in this commissure
feature is symmetrical to the central longitudinal axis of body
602.
[0068] In another embodiment of commissure feature 600, illustrated
in FIG. 6E, three rows of substantially the same size square
eyelets 604 are disposed toward the distal end 620 of body 602 and
a single, elongated eyelet 606 is disposed near the proximal end
610 of the body. This commissure feature further includes a pair of
recesses 608 disposed on the side edges of body 602 near the distal
end 620.
[0069] FIG. 6F illustrates an embodiment of commissure feature 600
that is similar to that of FIG. 6E, but with recesses 608 disposed
near the proximal end 610 of body 602 (adjacent the single eyelet
608). The eyelets 604 in this commissure feature may be larger or
smaller than those in the commissure feature of FIG. 6E.
[0070] FIG. 6G illustrates an embodiment in which commissure
feature 600 includes four rows of eyelets 604 and an additional
elongated eyelet 608. It will be understood from this embodiment
that the number of rows of eyelets 608 may be varied as desired.
Body 602 further includes recesses 608 near its proximal end
610.
[0071] The commissure feature 600 of FIG. 6H is substantially the
same as that of FIG. 6G, but includes additional recesses 608 on
the distal end 620 of body 602 adjacent either side of the strut
614.
[0072] A commissure feature 600 with a slightly shorter body 602 is
illustrated in FIG. 6I. This commissure feature includes three rows
of eyelets 604 which are substantially evenly spaced on body 602.
The eyelets 604 in the first row (beginning at the proximal end 610
of body 602) are slightly larger than those in the second and third
rows. They also may be slightly smaller than the eyelets in the
other rows. The row of eyelets having a different size (smaller or
larger) need not be the first row, but may be any row. Further, the
different sized eyelets need not be limited to one row, but may be
disposed in any number of rows. Although commissure feature 600 is
depicted in FIG. 6I as slightly shorter but about the same width as
the commissure features depicted in FIGS. 6A-6H, the commissure
feature of FIG. 6I may have a body 602 that is slightly wider than
those of the other figures.
[0073] FIG. 6J illustrates yet a further embodiment of commissure
feature 600 having three rows of eyelets 604 of substantially the
same size and shape disposed on the shorter, body 602.
Additionally, this commissure feature includes a single, elongated
eyelet 606 disposed at the proximal end 610 of body 602, and a pair
of recesses 608 disposed on the side edges of the body near its
proximal end.
[0074] FIG. 6K illustrates a commissure feature 600 having three
dome-shaped bodies 602 connected in series via struts 614. In this
example, each dome-shaped body 602 has a pair of eyelets 604. The
two eyelets 604 may be the same size or different sizes as
illustrated. As seen in FIG. 6K, commissure feature 600 includes
three bodies 602, although it will be understood that commissure
feature 600 may include two, three, four, five, six or more bodies
602.
[0075] FIG. 6L illustrates a commissure feature 600 having three
dome-shaped bodies 602 connected in series via struts 614 similar
to that of FIG. 6K. In this example, however, two of the bodies 602
are connected via suspension struts 624. Suspension struts 624 may
provide greater flexibility for commissure feature 600 during valve
loading into a delivery device, in the process of delivery, and in
operation of the heart valve. As seen in FIG. 6L, in one example,
suspension struts 624 are formed as a pair of struts that diverge
at a first body and begin to converge halfway before meeting at a
second body 602. Suspension struts 624 may be formed in the shape
of a diamond as shown in FIG. 6L. Alternatively, instead of
diamond-shaped struts, struts 624 may form a serpentine spring,
flat coil. Bodies 602 may also be disjointed or connected by
suture, fabric and/or a polymer. In at least some examples, struts
624 may include radiopaque markers, interlocks for valve-in-valve
configurations, or delivery system interlock sites. Additionally,
though shown between bodies 602, struts 624 may be disposed above
and/or below each of the bodies.
[0076] As seen in FIG. 6M, the commissure feature need not include
three identical dome-shaped bodies, but may include oval bodies 602
having single eyelets. Oval bodies 602 may be disposed in series at
the end of the commissure feature 600 or may alternate with other
multiple-eyelet bodies in a column. It will be understood that
suspension struts 624 may connect any or all of the bodies
described herein.
[0077] FIG. 6N illustrates a commissure feature 600 having a
dome-shaped body 602 connected to a second body 602 having a square
configuration and four eyelets 604. Thus, in this configuration,
one body includes a single column of eyelets, while a second body
includes multiple columns of eyelets 604. As seen in FIGS. 6N and
6O, different-shaped bodies may be connected by single struts 614
or suspension struts 624.
[0078] Two square-shaped bodies 602 may be connected to form a
commissure feature 600 as seen in FIG. 6P. As seen in this
configuration, each body 602 includes four eyelets 604 arranged in
two rows and two columns. Suspension struts 624 connect the two
square-shaped bodies.
[0079] FIGS. 6Q and 6R illustrate two additional examples in which
the commissure features include square-shaped bodies connected to
rectangular bodies. In FIG. 6Q, a square-shaped body is connected
to a rectangular body 602 having two columns of three eyelets 604.
These two bodies 602 are connected via suspension struts 624. In
the examples shown in FIG. 6R, the square-shaped body 602 is
connected to a rectangular body 602 having two rows, each row
having three eyelets 604.
[0080] FIG. 6S illustrates a commissure feature having a
dome-shaped body 602 connected to a rectangular body having two
rows of eyelets, each row having three eyelets 604. It will be
understood that the present invention contemplates various
combinations of oval, dome-shaped, square. Moreover, the eyelets
may also be circular, rectangular, trapezoidal as well as any other
suitable shape.
[0081] Although the commissure features have been described herein
as having three or four row of eyelets, any number of rows and/or
columns of eyelets may be used, each row and/or column having any
number of eyelets. Preferably, the commissure features have at
least two rows of eyelets, more preferably at least three rows of
eyelets, with at least two eyelets in each row (in other words, at
least two columns of eyelets). Moreover, the shapes and sizes of
the eyelets in one or more rows may be the same as or different
from the shapes and sizes of the eyelets in the other rows.
Preferably, however, the shapes and sizes of the eyelets within
each row are substantially the same so that the commissure feature
has substantial symmetry with respect to the central longitudinal
axis of body 602.
[0082] FIG. 7A illustrates the previous version commissure feature
500, while FIG. 7B illustrates one of the commissure features 600
according to the present invention. Commissure feature 600 is
similar to that described above with reference to FIG. 6F and
includes an elongated eyelet 606, and three rows of square eyelets
604 having substantially the same size, each row having two
eyelets. Commissure feature 600 further includes a pair of recesses
608 near the proximal end of body 602 for severally attaching a
suture to the body. A silhouette of the end of a leaflet 750 is
superimposed over the commissure feature in each figure. As seen by
comparing FIGS. 7A and 7B, commissure feature 600 has a larger area
and more eyelets than commissure feature 500. As a result, leaflet
750 maybe supported by a larger area with commissure feature 600
then with commissure feature 500. Thus, the load exerted on
leaflets 750 may be distributed more uniformly over a larger area
with commissure feature 600, resulting in better performance and
less likelihood of failure as compared to commissure feature 500.
Moreover, as will be discussed in greater detail, suture attachment
to commissure feature 500 typically results in a terminating knot
in a cell of the stent below the commissure feature 500. Instead,
as will be described below, termination of the suture attachment is
disposed in the most distal eyelet within the commissure feature.
The top portion of leaflet 750 may be aligned above, below or
in-line with the top of the commissure attachment.
[0083] FIG. 7C illustrates another example of a commissure feature
according to the present invention. Commissure feature 700 of FIG.
7C combines desirable features of both commissure features 500 and
600 described above. Specifically, commissure feature 700 is both
shorter and narrower to allow for more flexibility when tracking
over a curve. Moreover, when collapsed, commissure feature 700 is
less likely to interfere with adjacent struts because it can nest
within thin support struts between the aorta and annulus sections
without interference. The suture attachment is allowed to terminate
in the bottom T-shaped eyelet 706 of commissure feature 700.
Additionally, the leaflet belly suture itself may terminate within
the commissure feature so as to protect it during crimping,
loading, resheathing, and distortion after implant.
[0084] In addition to the improved commissure feature, the leaflets
may be constructed to yield improved performance. For example, the
size, shape and curvature of the leaflets may be chosen to
correspond to the commissure feature to which the leaflets will be
attached. FIGS. 8A-C illustrates several embodiments of leaflets
exhibiting these design considerations.
[0085] FIG. 8A illustrates a previous version of a leaflet 750
having a free edge 752 for coapting with other leaflets and a tab
754 at each end of the free edge for attaching the leaflet to a
commissure feature. In some examples, two leaflets may be attached
to each other and to a commissure feature.
[0086] FIG. 8B illustrates a leaflet 850 according to the present
invention. Leaflet 850 has a free edge 852 for coapting with other
leaflets and a tab 854 at each end of the free edge for attaching
the leaflet to a commissure feature. As seen by comparing the
leaflets in FIGS. 8A and 8B, the dimensions and shapes of a leaflet
may be modified to improve performance. Specifically, the tab 754
of leaflet 750 is formed with height y1 and width x1. While this
height and width may be sufficient to fully cover the previous
version commissure feature 500, they may be too small to fully
cover the longer commissure features 600 of the present invention.
In contrast, the tab 854 of leaflet 850 may have an increased
height of y2, enabling the tab to fully cover, and even extend
beyond the height of, commissure feature 600. Tab 854 may also have
a greater width x2 than tab 754. This greater width provides tab
854 with a greater area to fold about fold line 856 and attach to a
commissure feature 600, thereby providing leaflet 850 with greater
abrasion resistance. The height of the belly portion of the
leaflets may also be modified. As seen in FIG. 8A, leaflet 750 has
a belly height of f1 between the bottom of the leaflet and the free
edge 752. In contrast, the belly height f2 of leaflet 850 may be
greater. Without being bound by any particular theory, it is
believed that the greater belly height of leaflet 850 may allow for
better leaflet coaptation in elliptical and other distorted
configurations.
[0087] FIG. 8B further illustrates the use of an additional
reinforcement material 860 being used as a stress distributor,
reinforced and buffer. A thin layer of reinforcement material 860
may be is sandwiched and/or disposed between the folded layers of
tab 854. The tab 854 may be folded over the reinforcement material
860 to provide additional strength and support to the
leaflet-commissure attachment area. The reinforcement material 860
may be a fabric, tissue or polymer sheet material and may be
attached via sutures, bio-glue, weaving and or slots in the
reinforcement material.
[0088] As seen in FIGS. 8C and 8D, additional material may be
attached to tabs 854 in the tabs may be formed with additional
structures. For example, in FIG. 8C, each tab 854 includes an
additional flap 858 and an additional fold line 856. Flaps 858 may
be formed unitarily with tabs 854 or separately and then attached
to the tabs. Flaps 858 may be formed from the same material as tabs
854 or join a different material. The additional flap 858 may be
disposed on the top of tab 854, as shown in FIG. 8D. In addition,
leaflet 850 may have a single elongated tab 854 on only one side of
the leaflet, the elongated tab 854 being wide enough to wrap over
an end or tab of the next adjacent leaflet before attaching to a
commissure feature.
[0089] The size and shape of the free edge of the valve leaflets
may also be modified to further improve performance. As seen in
FIG. 9A, free edge 752 of leaflet 750 has a curved portion c1 which
attaches to tab 754 at junction 910. When attached to a commissure
feature, especially a larger commissure feature 600, such a
configuration may limit the performance and movement of free edge
752. A leaflet 850 according to the present invention may be formed
as illustrated in FIG. 9B. Leaflet 850 may include a free edge 852
having a curved portion c2 coupled to tab 854. Tab 854 may include
a substantially vertical edge 855 having a height v1. Curved
portion c2 may attach to tab 854 at junction 910 adjacent vertical
edge 855. Providing a vertical edge 855 on tab 854 may facilitate
suturing of the tab to the commissure feature without interfering
with the function of the free edge 852 of the leaflet.
[0090] In addition to modifying the commissure feature and the
leaflet configuration, the suture pattern attaching the leaflets to
the commissure features may also be modified to improve
performance. One example of a modified suture pattern according to
the present invention is illustrated in FIGS. 10A and 10B. FIG. 10A
illustrates the leaflet-commissure feature attachment as seen from
the ablumenal side of a valve assembly, while FIG. 10B illustrates
the same attachment as seen from the lumenal side of the valve
assembly.
[0091] As seen in FIG. 10A, a commissure feature 600 includes a
body 602 having a proximal end 610 and a distal end 620 similar to
the examples described in FIGS. 6A-J. Commissure feature 600 may
include a plurality of eyelets 604 disposed toward the distal end
620 of body 602 and a single, elongated eyelet 606 disposed near
the proximal end 610 of the body. Commissure feature 600 may also
include a pair of recesses 608 disposed on the side edges of body
602 near the proximal end 610 thereof. The plurality of eyelets may
include six substantially square eyelets 604 arranged in three rows
with two eyelets in each row. Eyelets 604a and 604b are disposed in
the first row of eyelets, beginning at the proximal end 610 of body
602. Eyelets 604c and 604d are arranged in the middle row of
eyelets, and eyelets 604e and 604f are arranged in the most distal
row of eyelets.
[0092] As seen in FIG. 10B, the tabs 854 of two different leaflets
850 are attached to commissure feature 600 using a suture or
multiple sutures. The following describes the use of, a single
suture S to attach leaflets 850 to commissure feature 600. It will
be understood, however, that multiple sutures may be used for this
purpose. For example, one suture may attach a first leaflet 850 to
commissure feature 600, while a second, separate suture attaches
the second leaflet 850 to the commissure feature.
[0093] The use of a single suture to attach two leaflets 850 to a
commissure feature 600 will be described with reference to FIG.
10C, which shows an enlarged view of the leaflet-commissure
assembly from the ablumenal side of the valve assembly and depicts
the suture pattern through several positions p1-16 on the assembly.
It will be appreciated that FIG. 10B shows the corresponding suture
pattern from the lumenal side of the valve assembly and that the
suture pattern may be understood from this view as well.
[0094] The suture pattern may begin at any point at or near
commissure feature 600 and terminate at any other point. In at
least some examples, the suture pattern begins and terminates at
the same position. For the sake of illustration, the suture pattern
will be described as beginning at point P1, within eyelet 604b. As
used herein, with reference to FIG. 10C and other figures showing
the ablumenal side of the valve assembly, the term "out" indicates
passing the sutures S from the lumenal side of the valve through
the leaflet tab 854 and past the stent structure to the ablumenal
side of the valve while the term "in" indicates passing the suture
from the ablumenal side of the valve past the stent structure and
through the leaflet tab 854 to the lumenal side of the valve.
[0095] The suture pattern S may begin by passing suture S out
through eyelet 604b at point p1. Suture S may then be advanced in
through point p2 in eyelet 604d, back out through point p3 in
eyelet 604b, and finally in through point p4 in eyelet 604d,
essentially forming two loops of suture S around rib 651. Suture S
may then be directed up toward eyelet 604f and passed out through
point p5 in eyelet 604f adjacent central spine 655, and then in
through point p6 in eyelet 604e adjacent the opposite side of the
central spine subsequently, suture S may be passed out through
point p7 in eyelet 604c in through point p8 in eyelet 604a, back
out through point p9 in eyelet 604c, and back in through point p10
in eyelet 604a, essentially forming two loops of sutures around rib
657. Suture S may then be directed down toward elongated eyelet 606
and passed out through point p11 in eyelet 606, over the side edge
of body 602 at point p12 positioned within recess 608, back out
through point p13 in eyelet 606, in through point p14 in the same
eyelet, around the side edge of body 602 at point p15 within the
second recess 608, and in through point p16 in eyelet 606. The tail
(not shown) of suture S at point p16 may then be knotted, tied or
otherwise joined to the tail (not shown) of the suture at point p1
to complete the attachment of commissure feature 600.
[0096] As seen in FIG. 10C, two optional loops L1 and L2 may be
used to tie the leaflets 850 to the commissure feature 600 at the
distal end 620 of body 602. Loops L1 and L2 may be formed from one
or more lengths of suture separate from suture S. Loop L1 may begin
at point p17 in eyelet 604e, and loop over the top of body 602,
with the ends of the loop tied together. Loop L2 may form a similar
attachment at point p18 in eyelet 604f. As described above with
particular reference to FIG. 6H, body 602 may have recesses formed
on the distal end 620 of body 602 to aid in securing the loop
sutures.
[0097] Another example of a suture pattern according to the present
invention is illustrated in FIGS. 11A and 11B. FIG. 11A illustrates
the leaflet-commissure feature attachment as seen from the
ablumenal side of a valve assembly, while FIG. 11B illustrates the
same attachment as seen from the lumenal side of the valve
assembly.
[0098] As seen in FIG. 11A, a commissure feature 600 has a body 602
with a proximal end 610 and a distal end 620 similar to the
examples described in FIGS. 6A-J. Commissure feature 600 may
include a single, elongated eyelet 606 disposed near the proximal
end 610 of body 602 and six substantially square eyelets 604
disposed toward the distal and 620 of the body, the eyelets being
arranged in three rows of two eyelets each. Eyelets 604a and 604b
are disposed in the first row of eyelets, beginning the proximal
end 610 of body 602. Eyelets 604c and 604d are arranged in the
middle row of eyelets, and eyelets 604e and 604f are arranged in
the most distal row of eyelets. A pair of recesses 608 may be
provided in the side edges of body 602 near the proximal end 610
thereof.
[0099] As seen in FIG. 11B, the tabs 854 of two different leaflets
850 are attached to commissure feature 600 using a sutures. The
suture pattern depicted in FIG. 11A is similar to the pattern
described above with reference to FIGS. 10A-C. In addition to the
horizontal stitches (as seen in FIG. 11A) within and around
elongated eyelet 606 and the vertical stitches (as seen in FIG.
11A) connecting eyelet 604a to eyelet 604c and eyelet 604d to
eyelet 604b, the suture pattern incorporates the two most distal
eyelets 604e and 604f using an "X" pattern. More particularly,
suture S may pass out through eyelet 604f at point p1, travel
diagonally over the central spine 655 of body 602 and in through
point p2 in eyelet 604e, travel horizontally (as seen in FIG. 11A)
under the central spine and back out through point p3 in eyelet
604f, and then travel diagonally over the central spine again (in
the opposite orientation) and in through point p4 in eyelet 604e,
creating an "X" pattern on the ablumenal surface of the valve
assembly. It will be understood that this portion of the pattern
may be incorporated as part of a single suture pattern coupled to
the suture pattern in the other eyelets 604a-d and/or in the
elongated eyelet 606, or may be formed as a separate suture pattern
and tied together.
[0100] Another example a suture pattern according to the present
invention is illustrated in FIGS. 12A and 12B. FIG. 12A illustrates
the leaflet-commissure feature attachment as seen from the
ablumenal side of a valve assembly, while FIG. 12B illustrates the
same attachment as seen from the lumenal side of the valve
assembly.
[0101] The pattern of suture S illustrated in FIGS. 12A and 12B is
similar to that described above with reference to FIGS. 11A and
11B, except that the distal "X" pattern is disposed on the lumenal
side of the valve assembly as opposed to on the ablumenal side of
the assembly. When viewed from the ablumenal side of the assembly
the suture pattern merely reveals a horizontal stitch between
eyelets 604e and 604f.
[0102] A suture pattern according to the present invention disposed
on a commissure feature 600 having only six eyelets is illustrated
in FIGS. 13A and 13B. FIG. 13A illustrates the leaflet-commissure
feature attachment as seen from the ablumenal side of a valve
assembly, while FIG. 13B illustrates the same attachment as seen
from the lumenal side of the valve assembly.
[0103] The suture pattern, shown in FIGS. 13A and 13B is similar to
that described above with references to FIGS. 11A and 11B, without
the proximal portion of the pattern incorporating elongated eyelet
606. It will be understood that the patterns described herein are
merely exemplary and that combinations of these patterns may be
made as desired depending on the particular structure of the
commissure feature being used. Moreover, in addition to the overall
suture pattern, the order of the pattern may also be modified. For
example, the commissure attachment feature may be assembled
clockwise or counter-clockwise, front to back, back to front, left
to right, right to left, or eyelets may be skipped and then later
attached. This allows for different varying levels of security,
stress concentrations, abrasion points as well as symmetrical and
non-symmetrical attachments.
[0104] Although the invention herein has been described with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims. It will be appreciated
that the various dependent claims and the features set forth
therein can be combined in different ways than presented in the
initial claims. It will also be appreciated that the features
described in connection with individual embodiments may be shared
with others of the described embodiments.
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