U.S. patent application number 14/158509 was filed with the patent office on 2014-09-18 for stents, valved-stents and methods and systems for delivery thereof.
This patent application is currently assigned to Symetis SA. The applicant listed for this patent is Symetis SA. Invention is credited to Serge Delaloye, Stephane Delaloye, Jacques Essinger, Jean-Luc Hefti.
Application Number | 20140277402 14/158509 |
Document ID | / |
Family ID | 40083683 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140277402 |
Kind Code |
A1 |
Essinger; Jacques ; et
al. |
September 18, 2014 |
STENTS, VALVED-STENTS AND METHODS AND SYSTEMS FOR DELIVERY
THEREOF
Abstract
Embodiments of the present disclosure are directed to stents,
valved-stents, (e.g., single-stent-valves and double
stent/valved-stent systems) and associated methods and systems for
their delivery via minimally-invasive surgery. The stent component
comprises a first stent section (102) a second stent section (104)
a third stent section (106) and a fourth stent section (108).
Inventors: |
Essinger; Jacques; (St-Prex,
CH) ; Delaloye; Serge; (Chamoson, CH) ; Hefti;
Jean-Luc; (Cheseaux-Noreaz, CH) ; Delaloye;
Stephane; (Bulach, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Symetis SA |
Lausanne |
|
CH |
|
|
Assignee: |
Symetis SA
Lausanne
CH
|
Family ID: |
40083683 |
Appl. No.: |
14/158509 |
Filed: |
January 17, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12739117 |
Apr 21, 2010 |
8647381 |
|
|
PCT/EP2008/064558 |
Oct 27, 2008 |
|
|
|
14158509 |
|
|
|
|
61052560 |
May 12, 2008 |
|
|
|
61067189 |
Feb 25, 2008 |
|
|
|
61000587 |
Oct 25, 2007 |
|
|
|
Current U.S.
Class: |
623/2.1 |
Current CPC
Class: |
A61F 2230/0054 20130101;
A61F 2/24 20130101; A61F 2230/0013 20130101; A61F 2220/0075
20130101; A61F 2230/005 20130101; A61F 2/2436 20130101; A61F
2230/0078 20130101; A61F 2/2418 20130101; A61F 2250/0098
20130101 |
Class at
Publication: |
623/2.1 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A replacement valve for use within a human body comprising: a
stent component comprising a first end and a second end wherein the
first end is the proximal end of the replacement valve and the
second end is the distal end of the replacement valve, the stent
component further comprising a plurality of sections including: a
first stent section defining an at least partly conical body,
wherein the first stent section defines the proximal end of the
stent component; a second stent section in communication with the
first stent section and defining an at least partly conical body,
wherein the conical body of the first stent section slopes
outwardly in the direction of the first end, and wherein the
conical body of the second stent section slopes outwardly in the
direction of the second end; a distal stent section defining an at
least partly conical body, wherein the distal stent section defines
the second end.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 12/739,117, filed Apr. 21, 2010, which is a 35
U.S.C. .sctn.371 national stage entry of PCT/EP2008/064558 which
has an international filing date of Oct. 27, 2008 and claims
priority to U.S. Provisional Application Nos. 61/000,587 filed Oct.
25, 2007; 61/067,189 filed Feb. 25, 2008, and 61/052,560, filed May
12, 2008, each disclosure of which in their entirety, is herein
incorporated by reference.
FIELD OF THE DISCLOSURE
[0002] Embodiments of the present disclosure are directed to
systems, methods, and devices for cardiac valve replacement in
mammalian hearts.
BACKGROUND OF THE DISCLOSURE
[0003] Conventional approaches for cardiac valve replacement
require the cutting of a relatively large opening in the patient's
sternum ("sternotomy") or thoracic cavity ("thoracotomy") in order
to allow the surgeon to access the patient's heart. Additionally,
these approaches require arrest of the patient's heart and a
cardiopulmonary bypass (i.e., use of a heart-lung bypass machine to
oxygenate and circulate the patient's blood). In recent years,
efforts have been made to establish a less invasive cardiac valve
replacement procedure, by delivering and implanting a cardiac
replacement valve via a catheter percutaneously (i.e., through the
skin) via either a transvascular approach--delivering the new valve
through the femoral artery, or by transapical route, where the
replacement valve is delivered between ribs and directly through
the wall of the heart to the implantation site.
[0004] While less invasive and arguably less complicated,
percutaneous heart valve replacement therapies (PHVT) still have
various shortcomings, including the inability for a surgeon to
ensure proper positioning and stability of the replacement valve
within the patient's body. Specifically, if the replacement valve
is not placed in the proper position relative to the implantation
site, it can lead to poor functioning of the valve. For example, in
an aortic valve replacement, if the replacement valve is placed too
high, it can lead to valve regurgitation, instability, valve
prolapse and/or coronary occlusion. If the valve is placed too low,
it can also lead to regurgitation and mitral valve interaction.
[0005] To address such risks, recapture procedures and systems have
been developed. For example, such a system is disclosed in U.S.
publication no. 20050137688 and U.S. Pat. No. 5,957,949, each
disclosure of which is herein incorporated by reference. While such
systems may address the problem of improper placement, they are
somewhat complicated, requiring the use of wires which are
removable attached to an end of the stent to pull the stent back
into the delivery catheter.
[0006] Throughout this description, including the foregoing
description of related art, any and all publicly available
documents described herein, including any and all U.S. patents, are
specifically incorporated by reference herein in their entirety.
The foregoing description of related art is not intended in any way
as an admission that any of the documents described therein,
including pending United States patent applications, are prior art
to embodiments according to the present disclosure. Moreover, the
description herein of any disadvantages associated with the
described products, methods, and/or apparatus, is not intended to
limit inventions disclosed herein. Indeed, aspects of the disclosed
embodiments may include certain features of the described products,
methods, and/or apparatus without suffering from their described
disadvantages.
SUMMARY OF THE DISCLOSURE
[0007] In some embodiments, a replacement valve for use within a
human body is provided, where the replacement valve includes a
valve component and a stent component (the replacement valve also
being referred to as a valved-stent or a stent valve, and may he
used interchangeably with replacement valve throughout the
disclosure). The stent component defines a first (e.g., proximal)
end and a second (e.g., distal) end and may include a plurality of
stent section, and in some embodiments, at least four stent
sections. The proximal end P of the stent component may be
described as the end of the stent component/replacement valve which
ultimately is positioned adjacent and/or within the left ventricle.
Alternatively, the proximal end P of the stent component may be
described as the end having anchoring elements for attachment to
the delivery catheter (e.g., attachment end in a transapical
delivery system). The distal end D of the stent component may be
described as the end of the replacement valve/stent component which
ultimately is positioned adjacent and/or near the ascending aorta,
when, for example, the delivery catheter is advanced toward/into
the ascending aorta in a transapical delivery system. According to
preferred embodiments of the disclosure, the replacement valves
according to at least some embodiments are released
distal-to-proximal, that is, the end of the stent (replacement
valve) which ultimately is positioned within/near/adjacent the
aorta is released first, and the end of the stent (replacement
valve) which ultimate is positioned within/near/adjacent the
ventricle is released last. Such a delivery, according to preferred
embodiments, is via a transapical approach, or through the heart
muscle (as opposed to being delivered transvascularly). While
preferred embodiments disclosed herein are described as being
delivered through a direct heart access approach (e.g., transapical
approach using transapical/direct access delivery systems), some
embodiments of the present invention may be delivered
transvascularly.
[0008] The first stent section may define an at least partly
conical body and the first end of the stent component. The conical
body of the first stent section may slope outwardly in the
direction of the first end. In some embodiments, the first stent
section may include at least one attachment element for removable
attachment to a delivery device.
[0009] The second stent section may be in communication with the
first stent section and may define an at least partly conical body.
The conical body of the second stent section may slope outwardly in
the direction of the second end.
[0010] The third stent section may be in communication with the
second stent section and may define an at least partially
cylindrical body. The third stent section may be configured to
house at least a portion of the valve component. The third stent
section may include a plurality of arches for fixation to a
corresponding plurality of commissures of the valve component.
[0011] The fourth stent section may be in communication with the
third stent section and may define the second end. The fourth stent
section may further define an at least partly conical body, which
may slope outwardly in the direction of the second end. The fourth
stent section may include a plurality of arches larger than, but
aligned with, the plurality of arches included in the third stent
section.
[0012] The four stent sections may be formed, for example, by laser
cutting a tube or single sheet of material (e.g., nitinol). For
example, the stent may be cut from a tube and then step-by-step
expanded up to its final diameter by heat treatment on a mandrel.
As another example, the stent may be cut from a single sheet of
material, and then subsequently rolled and welded to the desired
diameter.
[0013] In some embodiments of the present disclosure, a stent
component may be provided that includes a central, longitudinal
axis and at least one attachment element for removable attachment
to a delivery device. The at least one attachment element may be
formed generally in the shape of a hook extending inwardly towards
the central, longitudinal axis. The delivery device may include a
stent holder comprising a groove for receiving the attachment
element of the stent component, wherein release of the stent-valve
from the stent holder may be facilitated by rotation of the stent
holder relative to the attachment element.
[0014] In still other embodiments of the present disclosure, a
replacement valve for use within a human body is provided that
includes a valve component, a stent component for housing the valve
component, and at least two skirts (e.g., polyester (PET) skirts).
An inner skirt may be provided that covers at least a portion
(e.g., all) of an outer surface of the valve component, where the
inner skirt may be sutured to at least the inflow tract of the
valve component and to an inner surface of the stent. An outer
skirt may also be provided that is sutured onto an outer surface of
the stent.
[0015] Some embodiments of the present disclosure provide a cardiac
stent-valve delivery system that includes an inner assembly and an
outer assembly. The inner assembly may include a guide wire lumen
(e.g., polymeric tubing) and a stent holder for removable
attachment to a stent-valve. The outer assembly may include a
sheath. The inner member and the outer member may be co-axially
positioned and slidable relative to one another in order to
transition from a closed position to an open position, such that in
the closed position the sheath encompasses the stent-valve still
attached to the stent holder and thus constrains expansion of the
stent-valve. In the open position, the outer sheath may not
constrain expansion of the stent-valve and thus the stent-valve may
detach from the stent holder and expand to a fully expanded
configuration.
[0016] In some embodiments, the inner assembly of the delivery
device may include a fluoroscopic marker fixed to the guide wire
lumen distal of the stent holder.
[0017] In some embodiments, the diameter of the outer assembly of
the delivery device varies over its longitudinal axis.
[0018] In still other embodiments, the delivery system comprises a
rigid (e.g., stainless steel) shaft in communication with a
proximal end of the guide wire lumen.
[0019] In some embodiments, the delivery system comprises a luer
connector in communication with the rigid shaft.
[0020] In some embodiments of the present disclosure, a method is
provided for replacing an aortic valve within a human body. A
stent-valve may be covered with a sheath in order to maintain the
stent-valve in a collapsed configuration. The stent-valve may then
may be inserted in the collapsed configuration into the human body
without contacting the ascending aorta or aortic arch. The
stent-valve may be partially expanded by sliding the sheath towards
the left ventricle of the heart. This sliding of the sheath towards
the left ventricle may cause expansion of a distal end of the
stent-valve while the proximal end of the stent-valve remains
constrained by the sheath. The sheath may be further slid towards
the left ventricle of the heart in order to cause full expansion of
the stent-valve. In some embodiments, the stent-valve may be
recaptured prior to its full expansion by sliding the sheath in the
opposite direction.
[0021] In some embodiments, a method for cardiac valve replacement
is provided that includes releasing a distal end of a stent-valve
from a sheath, where the distal end includes a radiopaque marker
positioned thereon. The stent-valve is rotated, if necessary, to
orient the stent-valve appropriately with respect to the coronary
arteries (e.g., to prevent the commissures from facing the coronary
arteries). Arches of the stent-valve are released from the sheath,
in order to cause the arches to contact the aorta. A first conical
crown of the stent-valve is released from the sheath, in order to
cause the first conical crown to contact the native valve leaflets.
A second crown of the stent-valve is released from the sheath, in
order to cause the second crown to contact an annulus/inflow tract.
The second crown may be the proximal section of the stent-valve
such that releasing the second crown causes the stent-valve to be
fully released from the sheath.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] For a better understanding of the embodiments of the present
disclosure, reference is made to the following description, taken
in conjunction with the accompanying drawings, in which like
reference characters refer to like parts throughout, and in
which:
[0023] FIG. 1A is a side view of a stent component configured for
distal-to-proximal expansion according to some embodiments of the
present disclosure.
[0024] FIG. 1B shows the placement of a double polyester (PET)
fabric skirt (dashed line representing inner PET fabric skirt 122
and outer PET fabric skirt 126) relative to a stent component, as
well as placement of a valve-component within the stent (e.g.,
aortic biologic valve prosthesis, dashed line 124).
[0025] FIG. 2A shows an unrolled, flat depiction of another
embodiment of a stent component according to some embodiments of
the present disclosure.
[0026] FIG. 2B is a side view of a stent component shown in FIG.
2A.
[0027] FIG. 3A show a stent design with longitudinal elements for
commissural valve fixation.
[0028] FIG. 3B shows an unrolled, flat depiction of the stent
design of FIG. 3A.
[0029] FIG. 4 shows an unrolled, flat depiction of an alternative
design based on similar embodiments, without reinforcement
crown,
[0030] FIG. 5 and FIG. 6 show the size and shape of the anchoring
crowns for the stent component in the expanded configuration
according to some embodiments of the disclosure.
[0031] FIG. 7 shows the size and shape of stabilization arches for
the stent component in the expanded configuration according to some
embodiments of the disclosure.
[0032] FIG. 8 shows a mating couple between attachment elements of
the stent component and a stent-holder of a delivery device,
according to some embodiments of the present disclosure.
[0033] FIG. 9 shows the design of multiple fixation elements (e.g.,
"holes") that allow for the fixation of the stent onto the catheter
when the stent is crimped or in the collapsed configuration.
[0034] FIG. 10 shows the tip of the elements forming the anchoring
crown, which may be bent towards the longitudinal axis of the stent
thereby avoiding potential injury, such as injury to the sinus of
vasalva during implantation of the device.
[0035] FIG. 11A shows an embodiment of the present disclosure,
wherein the stabilization arches are designed to be independent of
the valve fixation devices.
[0036] FIG. 11B shows an embodiment of the present disclosure,
wherein the stabilization arches are designed with gradual
stiffness change and connected to valve fixation arches.
[0037] FIG. 12 illustrates a placement of a double polyester (PET)
fabric skirt relative to a stent component, according to some
embodiments of the present disclosure.
[0038] FIG. 13 shows the in vivo migration of a stent according to
the present disclosure, wherein the design of the stent allows for
a self-positioning under diastolic pressure.
[0039] FIG. 14A shows a delivery system for distal-to-proximal
expansion of a stent-valve, according to some embodiments of the
present disclosure.
[0040] FIG. 14B shows the size and shape of delivery system
according to some embodiments.
[0041] FIGS. 15A-D illustrate a method of implanting a stent-valve
within a human heart according to some embodiments of the present
disclosure.
[0042] FIGS. 16A-D illustrate the partial release of a stent
according to the present disclosure, the release of which is
stopped by a security tab.
[0043] FIGS. 17A-D illustrate the capture of the stent after
partial release according to FIG. 16.
[0044] FIGS. 18A-C illustrate the full release of a stent according
to some embodiments of the present disclosure.
DETAILED DESCRIPTION
[0045] Some embodiments of the present disclosure are directed to
systems, methods, and devices for cardiac valve replacement. For
example, such methods, systems, and devices may be applicable to
the full range of cardiac-valve therapies including, for example,
replacement of failed aortic, mitral, tricuspid, and pulmonary
valves. Some embodiments may facilitate a surgical approach on a
beating heart without the need for an open-chest cavity and
heart-lung bypass. This minimally-invasive surgical approach may
reduce the risks associated with replacing a failed native valve in
the first instance, as well as the risks associated with secondary
or subsequent surgeries to replace failed artificial (e.g.,
biological or synthetic) valves.
Stents, Stent-Valves/Valved-Stents
[0046] Some embodiments of the present disclosure relate to stents
and stent-valves or valved-stents. Valved-stents according to some
embodiments of the present disclosure may include a valve component
and at least one stent component (e.g., a single-stent-valve or a
double-stent-valve). The valve component may include a biological
valve (e.g., bovine harvested valve), a synthetic valve (e.g.,
either synthetic valve leaflet material and/or a mechanical valve
assembly), any other suitable material(s). The stent and valve
components according to some embodiments may be capable of at least
two configurations: a collapsed or contracted configuration (e.g.,
during delivery) and an expanded configuration (e.g., after
implantation).
[0047] According to some embodiments, the valved-stent or
stent-valves of the present disclosure may be used as replacement
heart valves and may be used in methods for replacing diseased or
damaged heart valves. Heart valves are passive structures that
simply open and close in response to differential pressures on
either side of the particular valve. Heart valve comprise moveable
"leaflets" that open and close in response to differential
pressures on either side of the valve's leaflets. The mitral valve
has two leaflets and the tricuspid valve has three. The aortic and
pulmonary valves are referred to as "semilunar valves" due to the
unique appearance of their leaflets or "cusps" and are shaped
somewhat like a half-moon. The aortic and pulmonary valves each
have three cusps.
[0048] The valve component is preferably designed to be flexible,
compressible, host-compatible, and non-thrombogenic. The valve
component can be made from various materials, for example, fresh,
cryopreserved or glutaraldehyde fixed allografts or xenografts.
Synthetic biocompatible materials such as polytetrafluoroethylene,
polyester, polyurethane, nitinol or other alloy/metal foil sheet
material and the like may be used. The preferred material for the
valve component is mammal pericardium tissue, particularly
juvenile-age animal pericardium tissue.
[0049] The valve component can be any replacement heart valve known
or used and cardiac replacement valves. Replacement heart valves
arc generally categorized into one of three categories: artificial
mechanical valves; transplanted valves; and tissue valves.
Mechanical valves are typically constructed from nonbiological
materials such as plastics, metals, and other artificial materials.
Transplanted valves are natural valves taken from cadavers. These
valves are typically removed and frozen in liquid nitrogen, and are
stored for later use. They are typically fixed in glutaraldehyde to
eliminate antigenicity. Artificial tissue valves are valves
constructed from animal tissue, such as bovine or porcine tissue.
Efforts have also been made at using tissue from the patient for
which the valve will be constructed. Such regenerative valves may
also me used in combination with the stent components described
herein. The choice of which type of replacement heart valves are
generally based on the following considerations: hemodynamic
performance, thrombogenicity, durability, and ease of surgical
implantation.
[0050] Most tissue valves are constructed by sewing the leaflets of
pig aortic valves to a stent to hold the leaflets in proper
position, or by constructing valve leaflets from the pericardial
sac of cows or pigs and sewing them to a stent. See e.g., U.S.
Patent Publication No. 2005/0113910, the disclosure of which is
herein incorporated by reference in its entirety. Methods of
creating artificial tissue valves is described in U.S. Pat. Nos.
5,163,955, 5,571,174, and 5,653,749, the disclosures of which are
herein incorporated by reference in their entireties.
[0051] According to some embodiment, the valve component is
preferably attached to the inner channel of the stent member. This
may be accomplished using any means known in the art. Preferably,
the valve component is preferably attached to the inner channel of
the stent member by suture or stitch, for example, by suturing the
outer surface of the valve component pericardium material to the
stent member. Preferably, the third stent section may be configured
to house at least a portion of the valve component. Other fixation
schemes can also be utilized. The attachment position of the valve
is preferably closer to the proximal end of the stent chosen with
the understanding that the annulus of the valve will preferably
engage the outer surface of the stent at the groove (see FIG. 15D;
1560) created at the junction between the first and second sections
of the stent component.
[0052] The stent component defines a first (e.g., proximal) end and
a second (e.g., distal) end and includes at least four stent
sections: a proximal conically shaped first section; a conically
shaped second section; an optional cylindrically shaped third
section; and a distal conically shaped forth section.
[0053] The first stent section may define an at least partly
conical body and the first end of the stent component. The conical
body of the first stent section may slope outwardly in the
direction of the first end. For example, FIG. 2 shows a conically
shaped first section 202 with an anchoring crown towards the
ascending aorta. In some embodiments, the first stent section may
include at least one attachment element for removable attachment to
a delivery device.
[0054] The second stent section may be in communication with the
first stent section and may define an at least partly conical body.
The conical body of the second stent section may slope outwardly in
the direction of the second end. For example, FIG. 2 shows a
conically shaped second section 204 with an anchoring crown towards
the left ventricle, or in the direction of blood flow (see e.g.,
FIG. 1).
[0055] The radial force of this section may be increased by
adjusting the length and angle (i.e., increased length H1 and angle
.alpha.1; see FIG. 5) of the stent struts to reduce the risk of
migration towards the left ventricle. In some embodiments, the tip
of the elements forming the anchoring crown may be bent towards the
longitudinal axis of the stent thereby avoiding potential injury of
the sinus of vasalva (see e.g., FIG. 10).
[0056] The third stent section may be in communication with the
second stent section and may define an at least partially
cylindrical body. The third stent section may be configured to
house at least a portion of the valve component. The third stent
section may include a plurality of arches for fixation to a
corresponding plurality of commissures of the valve component. For
example, FIG. 2 shows a cylindrical third section 206 which acts as
a reinforcement crown.
[0057] The free area between the three valve fixation arches may be
adjusted (i.e., increased or decreased) to improve the blood flow
to the coronary arteries. This section of the stent may be attached
to the previous anchoring crown (conically shaped section no 2) at
three positions (see e.g., FIG. 11). This may allow for the out of
plane bending of the elements of the section no 2 to form the
conical shape.
[0058] The fourth stent section may be in communication with the
third stent section and may define the second end. The fourth stent
section may further define an at least partly conical body, which
may slope outwardly in the direction of the second end. The fourth
stent section may include a plurality of arches larger than, but
aligned axially and/or circumferentially with, the plurality of
arches included in the third stent section.
[0059] Stabilization arches may be provided within the ascending
aorta that work independently of the valve fixation arches.
Variations of the ascending aorta diameter may therefore have no
impact on the valve fixation arches and thus on the valve
haemodynamic properties. Furthermore, in some embodiments,
stabilization arches may be provided that are connected to the
valve fixation arches in order to increase the free area between
the three valve fixation arches and thus improve the blood flow to
the coronary arteries. The specific design of the stabilization
arches with a gradual stiffness change allows the stabilization
arches to work independently of the valve fixation arches (see
e.g., FIG. 11). The three stabilization arches may reinforce in
this configuration the three valve fixation arches and thus reduce
their deflection towards the longitudinal axis of the stent under
diastolic pressure. Thus, according to some embodiments of the
present disclosure, the stabilization arches may be designed to be
independent of the valve fixation devices. See FIG. 11A. According
to some embodiments of the present disclosure, the stabilization
arches may be designed with gradual stiffness change and connected
to valve fixation arches. See FIG. 11B.
[0060] These four stent sections may be formed, for example, by
laser cutting a tube or single sheet of material (e.g., nitinol).
For example, the stent may be cut from a tube and then step-by-step
expanded up to its final diameter by heat treatment on a mandrel.
As another example, the stent may be cut from a single sheet of
material, and then subsequently rolled and welded to the desired
diameter.
[0061] FIG. 1A is a side view of a stent component 100 for
supporting a replacement valve, according to some embodiments of
the present disclosure, which is generally symmetrical in the
vertical plane about a longitudinal axis 101. The stent component
may be self-expanding and/or may be expanded via, for example, a
balloon. Such stents may be formed from a suitable material
familiar to those of skill in the art, which may include, for
example, stainless steel or a shape-memory material (e.g., nitinol)
or a combination of materials. In some embodiments, the stent
component may be laser cut from a single tube or sheet of such
material(s).
[0062] As shown in FIG. 1A, the stent component may comprise a
plurality of sections. For example, such a stent may comprise four
sections: 102, 104, 106, 108). Stent section 102, for example, may
define a proximal end of the stent component. In some embodiments
of the present disclosure, stent section 102 may be generally
conically shaped, and represent a section of a cone (e.g., a
truncated cone, frustrum, etc.), having a first plane of a first
smaller diameter, and a second plane spaced apart from the first
plane and having a second larger diameter than the first diameter.
In some embodiments, the two planes may be parallel.
[0063] According to some embodiments, stent section 102 has a shape
and size configured such that it may create a form fit with one
side (e.g., the inflow side) of the cardiac valve being replaced
(e.g., aortic valve), for example, and therefore prevent migration
of the valved-stent. If the stent is used in an aortic valve
replacement, the fit of section 102 that prevents (or substantially
prevents) migration of the valved-stent towards the ascending aorta
(or prevents migration of the stent component if the stent is used
as a positioning stent for receiving a second stent having the
valve component). Furthermore, section 102 may provide a radial
force, for example, that creates an additional friction fit against
the inflow tract/aortic annulus.
[0064] The second stent section 104 also may also have a generally
conical shape, according to some embodiments, and like section 102,
may represent a section of a cone (e.g., a truncated cone, a
frustrum, etc.) having a first plane of a first smaller diameter,
and a second plane spaced apart from the first plane and having a
second larger diameter than the first diameter. In some
embodiments, the two planes may be parallel. Blood flow may be in
the direction shown in FIG. 1A by arrow 110.
[0065] In some embodiments, the first planes of section 102 and
section 104, having the smaller radii, match (or substantially
match) and lie immediately adjacent one another, and may be joined
thereto as well. Thus, such an arrangement may correspond to two
inverted frustrums. According to some embodiments, stent section
104 has a size and shape configured such that it may create a form
fit with a second tract of the valve being replaced (e.g., the
outflow tract/native leaflets of the aortic valve). If the stent is
used for an aortic valve replacement, the fit of section 104 may
prevent (or substantially prevent) migration of the valved-stent
towards the left ventricle (or may prevent/substantially prevent
migration of the stent component if the stent is used as a
positioning stent for receiving a second stent having the valve
component). Furthermore, stent section 104 may also provide a
radial force that creates an additional friction fit against the
valve annulus (e.g., aortic annulus/outflow tract/native leaflets,
for example (e.g., an aortic valve replacement).
[0066] The third stent section 106, which may overlap with stent
section 104, and may also have a generally conical shape, according
to some embodiments, but in other embodiments, a substantial
portion or all of section 106 preferably more cylindrical in shape.
Section 106 preferably designates the portion of the stent
component to which the valve component/prosthesis may be affixed
onto the stent component. According to some embodiments, stent
section 106 may comprise a plurality of (e.g., two, three, four,
five, six, eight, etc.) arches which may be used, for example, for
the fixation of the valve commissures. In some embodiments, one or
more of the arches may also comprise additional reinforcements for
fixation of the valve prosthesis.
[0067] The fourth stent section 108, according to some embodiments,
may define a distal end of the stent component. In some
embodiments, stent section 108 may have a generally conical shape,
with the slant height of the conical shape oriented at an angle
having a direction which may correspond to a direction of the angle
of the slant height of stent section 104. In some embodiments,
stent section 108 may comprise a plurality of (e.g., two, three,
four, five, six, eight, etc.) arches, which may be larger than the
arches noted for section 106, where such arches may also be aligned
in the same direction with the arches of stent section 106. These
larger arches may be the first components of the stent to be
deployed during the distal to proximal release of the valved-stent
from its first, unexpanded configuration to its second, expanded
configuration in a cardiac valve replacement, for example, an
aortic valve replacement. In such an aortic valve replacement, the
deployed section 108 arches may be used to engage the ascending
aorta thereby orientating the delivery system/valved-sent
longitudinally within the aorta/aortic annulus, thus preventing any
tilting of the implanted valved-stent. In some embodiments, a
radiopaque marker 112 may be positioned on or close to an end
(e.g., the distal end) of at least one of the arches. A function of
such a radiopaque marker is described below in connection with
FIGS. 15A-D.
[0068] In some embodiments, the larger arches of stent section 108
may be at least partially of cylindrical shape when fully expanded
and may deform to a conical shape when only partially deployed.
This may result in lower local stresses in the aortic wall, thus
reducing the risks of inflammation/perforation.
[0069] In some embodiments, the overall stent length may be
sufficiently small so as to avoid conflict with, for example, the
mitral valve when the stent is being used for aortic valve
replacement. Of course, it will be understood that these dimensions
will vary depending on, for example, the type of valve used and the
dimensions given above are included as examples only and other
sizes/ranges are available which conform to the present
disclosure.
[0070] In still other embodiments of the present disclosure, a
replacement valve for use within a human body is provided that
includes a valve component, a stent component for housing the valve
component, and at least two skirts (e.g., polyester (PET) skirts).
An inner skirt may be provided that covers at least a portion
(e.g., all) of an outer surface of the valve component, where the
inner skirt may be sutured to at least the inflow tract of the
valve component and to an inner surface of the stent. An outer
skirt may also be provided that is sutured onto an outer surface of
the stent.
[0071] FIG. 1B shows one embodiment of a self expanding stent 100.
FIG. 1B shows the placement of a double polyester (PET) fabric
skirt (dashed line representing inner PET fabric skirt 122 and
outer PET fabric skirt 126) relative to a stent component, as well
as placement of a valve-component within the stent (e.g., aortic
biologic valve prosthesis, dashed line 124), according to some
embodiments of the present disclosure. An inner skirt may cover at
least a portion--for example, either a minor portion (e.g., less
than about 20% coverage), a substantial portion (e.g., about 50-90%
coverage), or all (e.g., 90%+) of the stent) of the outer surface
of the replacement valve. The skirt may be sutured to at least the
inflow tract of the valve and to the inner surface of the stent,
and may serve as a sealing member between the stent and the valve.
In some embodiments, the topology of the inner surface of this
fabric may be configured to improve blood flow. An outer skirt may
also be sutured onto the outer surface of the stent (dashed line
126) and may serve as a sealing member between the stent and, for
example, a native valve leaflets/cardiac valve (e.g., aortic)
annulus/inflow and/or outflow tract. In some embodiments, the
topology of the outer surface of this fabric may be configured to
improve endothelialisation, for example. The skirt may be made
using any know material used for such purposes. Preferably, the
skirt is comprised of a polyester material, such as a single ply
polyester material. The preferred polyester is polyethylene
terephthalate (PET).
[0072] A double PET fabric skirt may be provided in which the free
edge of the stent is covered to avoid injuries of the left
ventricle wall and mitral valve (see e.g., FIG. 12).
[0073] FIG. 2A shows an unrolled, flat depiction of another
embodiment of a stent component according to some embodiments of
the present disclosure. This stent component may be the same or
similar to the stent component of FIG. 1, and include the same
numbering scheme as set out for FIG. 1, except that the
corresponding reference numeral starts with a "2" instead of a "1".
The stent component illustrated in FIG. 2A includes some additional
features, mainly one or more additional reinforcements 214 for
stent section 206, as well as one or more attachment elements 216
in stent section 202. This numbering scheme is generally used
throughout the specification.
[0074] Additional reinforcements 214 may comprise arches, which may
be inverted as compared to the commissural arches currently
provided in stent section 206. Attachment elements 216 may be used
to removable attach the stent component to a delivery device (e.g.,
a catheter based system). In some embodiments, elements 216 may
serve to hold the stent-valve onto the delivery system until full
release of the stent during delivery/implantation, thus allowing
for, in some embodiments, the recapture of the stent upon partial
release. See FIG. 16-18. The attachment elements 216 may also
prevent the stent from "jumping out" of the delivery system just
prior to its full release--such jumping out may result in
inaccurate positioning of the replacement valve.
[0075] In some embodiments, a radiopaque marker 212 may be
positioned on or close to an end (e.g., the distal end) of at least
one of the arches. A function of such a radiopaque marker is
described below in connection with FIGS. 15A-D.
[0076] FIG. 2B show another design of the devices of the current
embodiments. The stent component illustrated in FIG. 2A-B includes
some additional features, mainly one or more additional
reinforcements 214 for stent section 206, as well as one or more
attachment elements 216 in stent section 202. Such attachment
elements may be formed generally in the shape of a bent, or curved
angled member (e.g., an "L" or "" like shape). In some embodiments,
such attachment elements may be a hook (e.g., a "J" like
shape).
[0077] Some embodiments of the present disclosure include, for
example stents and valved-stents: for anchoring towards the
ascending aorta; for anchoring towards the left ventricle; for
valve fixation; and/or for valved-stent stabilization, as well as
other possible applications.
[0078] FIGS. 3A-B and 4 show examples of stent designs based on
such embodiments.
[0079] FIGS. 3A and 3B show a stent design with longitudinal
elements for commissural valve fixation. FIG. 3B shows an unrolled,
flat depiction of the above stent design. These figures show the
stabilization arch 308 (conically shaped section), reinforcement
crown 306 (cylindrical section), longitudinal valve fixation
elements 320 (cylindrical section), forward anchoring crown 304
(e.g., towards LV or otherwise preventing movement of device in a
direction opposite of blood flow) (conically shaped section), and
reverse anchoring crown 302 (e.g., towards ascending aorta or
otherwise preventing movement of device in the direction of blood
flow) (conically shaped section).
[0080] An unrolled, flat depiction of an alternative design for a
stent without reinforcement crowns is in FIG. 4. FIG. 4 shows the
stabilization arch 408 (conically shaped section), longitudinal
valve fixation elements 420 (cylindrical section), forward
anchoring crown 404 (e.g., towards LV or otherwise preventing
movement of device in the direction of blood flow) (conically
shaped section), and reverse anchoring crown 402 (e.g., towards
ascending aorta or otherwise preventing movement of device in a
direction opposite of blood flow) (conically shaped section). The
reverse anchoring crown 402 may be comprised of two rows
(plurality) of meanders for improved stability. In preferred
embodiments, the fixation elements 420 together help to form the
cylindrical shape of the optional third section of the stent. That
is, the fixation elements 420 are preferably curved around the
longitudinal axis of the stent and, in some embodiments, may form
the circumference of the third section of the stent.
[0081] In some embodiments, a stent is presented which includes a
section for commissural valve fixation which is composed of a
plurality (e.g., two, three, four, five, six, eight, etc.)
longitudinal elements connected on one side to a conically shaped
section (for example) used for anchoring towards the left ventricle
and on the other side to the conically shaped section (for example)
used for stabilization.
[0082] According to some embodiments, the stent is designed to
better match the size and shape of a biological valve with narrow
commissural posts and, in some embodiments, allow a more robust
suturing of the valve commissural posts to the stent. Narrow
commissural posts according to some embodiments improve the
perfusion of the coronary arteries via the sinus of vasalva. To
reduce the deflection of the three longitudinal elements under
diastolic pressure, an additional reinforcement crown may be added
as well in some embodiments.
[0083] According to some embodiments, the stent design allowing for
the fixation of the valve commissural posts, according to some
embodiments, provides a further advantage, as the size and shape of
such stents preferably does not change substantially, and even more
preferably, does not change during a required crimping process for
loading the stent (with valve, "valved-stent") onto a delivery
catheter. Accordingly, this may reduce (and preferably does reduce)
the risks of suture damage and facilitating crimping and
subsequently releasing of the valved-stent (for example).
[0084] Although a number of embodiments are herein described, other
modifications are possible, and thus, the noted embodiments are for
illustrative purposes only.
[0085] FIG. 5 is provided to illustrate the dimensions of the first
and second sections of the stent component. With respect to the
first section, D3 represents the diameter of the most proximal edge
of the stent component in the expanded configuration. D2 represents
the diameter of the stent component at the juncture between the
first conical section 502 and second conical section 504 of the
stent component. H2 represents the axial distance between the
planes of the diameters D2 and D3 in the expanded configuration, or
the length of the first conical section in the expanded
configuration. D1 represents the diameter of the most distal edge
of the second conical section of the stent component in the
expanded configuration. H1 represents the axial distance between
the planes of the diameters D1 and D2 in the expanded
configuration, or the length of the second conical section in the
expanded configuration.
[0086] Preferably, the length of the first conical section H2 is
between about 3 to about 15 mm (e.g., about 3 mm, about 4 mm, about
5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm,
about 11 mm, about 12 mm, about 13 mm, about 14 mm, and about 15
mm). The length of the first conical section H2 may been adjusted
depending on the intended application of the stent of stent-valve.
For example, the length of the first conical section H2 may range
from about 3 to about 5 mm, about 3 to about 7 mm, about 3 to about
12 mm, about 3 to about 15 mm, about 3 to about 20 mm, about 5 to
about 10 mm, about 5 to about 12 mm, about 5 to about 15 mm, about
7 to about 10 mm, about 7 to about 12 mm, about 7 to about 15 mm,
about 10 to about 13 mm, about 10 to about 15 mm, or about 7 to
about 20 mm. For example, the length of this section may be on the
smaller end of the scale to avoid potential conflict with a cardiac
valve, such as the mitral valve.
[0087] The diameter of the first conical section at D3 is
preferably between about 22 mm to about 40 mm (e.g., about 22 mm,
about 23 mm, about 24 mm, about 25 mm, about 26 mm, about 27 mm,
about 28 mm, about 29 mm, about 30 mm, about 31 mm, about 32 mm,
about 33 mm, about 34 mm, about 35 mm, about 36 mm, about 37 mm,
about 38 mm, about 39 mm, and about 40 mm). This diameter of the
first conical section D3 may been adjusted depending on the
intended application of the stent of stent-valve. Thus, the
diameter of the first conical section in the expanded configuration
D3 may be from between about 15 mm to about 50 mm, from between
about 15 mm to about 40 mm, from between about 20 mm to about 40
mm, from between about 24 mm to about 40 mm, from between about 26
mm to about 40 mm, from between about 28 mm to about 40 mm, from
between about 30 mm to about 40 mm, from between about 32 mm to
about 40 mm, from between about 34 mm to about 40 mm, from between
about 36 mm to about 40 mm, from between about 38 mm to about 40
mm, from between about 22 mm to about 38 mm, from between about 22
mm to about 36 mm, from between about 22 mm to about 34 mm, from
between about 22 mm to about 32 mm, from between about 22 mm to
about 30 mm, from between about 22 mm to about 28 mm, from between
about 24 mm to about 34 mm, from between about 25 mm to about 35
mm, or from between about 25 mm to about 30 mm.
[0088] The diameter of the stent component D2 at the juncture of
the first and second conical sections D2 is preferably between
about 20 mm to about 30 mm (e.g., about 20 mm, about 21 mm, about
22 mm, about 23 mm, about 24 mm, about 25 mm, about 26 mm, about 27
mm, about 28 mm, about 29 mm, and about 30 mm). This diameter of
the stent component D2 may been adjusted depending on the intended
application of the stent of stent-valve. For example, this diameter
of the stent component D2 may be sized according to the shape of
the annulus of the cardiac valve. Thus, the diameter of the stent
component D2 may be from between about 15 mm to about 40 mm, from
between about 15 mm to about 30 mm, from between about 18 mm to
about 35 mm, from between about 22 mm to about 30 mm, from between
about 24 mm to about 30 mm, from between about 26 mm to about 30
mm, from between about 28 mm to about 30 mm, from between about 22
mm to about 28 mm, from between about 22 mm to about 26 mm, from
between about 20 mm to about 24 mm, from between about 20 mm to
about 26 mm, from between about 20 mm to about 28 mm, and from
between about 22 mm to about 32 mm.
[0089] The diameter of the second conical section at D1 is
preferably between about 22 mm to about 40 mm (e.g., about 22 mm,
about 23 mm, about 24 mm, about 25 mm, about 26 mm, about 27 mm,
about 28 mm, about 29 mm, about 30 mm, about 31 mm, about 32 mm,
about 33 mm, 34 mm, 35 mm, 36 mm, 37 mm, about 38 mm, about 39 mm,
and about 40 mm). This diameter of the second conical section D1
may been adjusted depending on the intended application of the
stent of stent-valve. Thus, the diameter of the first conical
section in the expanded configuration D1 may be from between about
15 mm to about 50 mm, from between about 15 mm to about 40 mm, from
between about 20 mm to about 40 mm, from between about 24 mm to
about 40 mm, from between about 26 mm to about 40 mm, from between
about 28 mm to about 40 mm, from between about 30 mm to about 40
mm, from between about 32 mm to about 40 mm, from between about 34
mm to about 40 mm, from between about 36 mm to about 40 mm, from
between about 38 mm to about 40 mm, from between about 22 mm to
about 38 mm, from between about 22 mm to about 36 mm, from between
about 22 mm to about 34 mm, from between about 22 mm to about 32
mm, from between about 22 mm to about 30 mm, from between about 22
mm to about 28 mm, from between about 24 mm to about 34 mm, from
between about 25 mm to about 35 mm, or from between about 25 mm to
about 30 mm.
[0090] Preferably, the length of the second conical section H1 is
between about 3 to about 10 mm (e.g., about 3 mm, about 4 mm, about
5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, and about 10
mm). The length of the first conical section H1 may been adjusted
depending on the intended application of the stent of stent-valve.
For example, the length of the first conical section H2 may range
from about 3 to about 5 mm, about 3 to about 15 mm, about 3 to
about 20 mm, about 5 to about 10 mm, about 7 to about 10 mm, about
7 to about 12 mm, about 7 to about 15 mm, about 10 to about 13 mm,
about 5 to about 15 mm, about 7 to about 20 mm. For example, the
length of this section may be on the smaller end of the scale to
avoid potential conflict with a cardiac valve, such as the mitral
valve.
[0091] FIG. 6 is provided to illustrate the dimensions of the first
and second sections of the stent component, and particularly the
angles of the anchoring crowns that help to define these conical
sections. The .alpha.1 angle defines the angle of the anchoring
crown of the second conical section of the stent component in the
expanded configuration. The .alpha.2 angle defines the angle of the
anchoring crown of the first conical section of the stent component
in the expanded configuration. The .alpha.3 angle defines the angle
of bending of the tip, which is done so as to prevent injuries of
sinus (see also, FIG. 10).
[0092] The .alpha.1 angle is preferably between from about 10
degree to about 80 degree (e.g., about 10 degree, about 15 degree,
about 20 degree, about 25 degree, about 30 degree, about 35 degree,
about 40 degree, about 45 degree, about 50 degree, about 55 degree,
about 60 degree, about 65 degree, about 70 degree, about 75 degree,
and about 80 degree), more preferably between from about 20 degree
to about 70 degree, most preferable between from about 30 degree to
about 60 degree. According to some embodiments, the .alpha.1 angle
is between from about 20 degree to about 80 degree, between from
about 20 degree to about 60 degree, between from about 20 degree to
about 50 degree, between from about 20 degree to about 45 degree,
between from about 40 degree to about 60 degree, between from about
45 degree to about 60 degree, between from about 30 degree to about
50 degree, between from about 30 degree to about 45 degree, between
from about 30 degree to about 40 degree, or between from about 25
degree to about 45 degree.
[0093] The .alpha.2 angle is preferably between from about 5 degree
to about 50 degree (e.g., about 5 degree, about 10 degree, about 15
degree, about 20 degree, about 25 degree, about 30 degree, about 35
degree, about 40 degree, about 45 degree, and about 50 degree),
more preferably between from about 10 degree to about 40 degree,
most preferable between from about 10 degree to about 30 degree.
According to some embodiments, the .alpha.2 angle is between from
about 5 degree to about 45 degree, between from about 5 degree to
about 40 degree, between from about 5 degree to about 30 degree,
between from about 5 degree to about 25 degree, between from about
5 degree to about 20 degree, between from about 5 degree to about
15 degree, between from about 10 degree to about 20 degree, between
from about 10 degree to about 25 degree, between from about 10
degree to about 30 degree, between from about 10 degree to about 40
degree, between from about 10 degree to about 45 degree, between
from about 15 degree to about 40 degree, between from about 15
degree to about 30 degree, between from about 15 degree to about 25
degree, between from about 20 degree to about 45 degree, between
from about 20 degree to about 40 degree, or between from about 20
degree to about 30 degree
[0094] The .alpha.3 angle is preferably between from about 0 degree
to about 180 degree (e.g., about 5 degree, about 10 degree, about
15 degree, about 20 degree, about 25 degree, about 30 degree, about
35 degree, about 40 degree, about 45 degree, about 50 degree, about
55 degree, about 60 degree, about 65 degree, about 70 degree, about
75 degree, about 80 degree, about 85 degree, about 90 degree, about
95 degree, about 100 degree, about 105 degree, about 110 degree,
about 115 degree, about 120 degree, about 125 degree, about 130
degree, about 135 degree, about 140 degree, about 145 degree, about
150 degree, about 155 degree, about 160 degree, about 165 degree,
about 170 degree, about 175 degree, and about 180 degree).
According to some embodiments, the .alpha.3 angle is between from
about 45 degree to about 90 degree, between from about 45 degree to
about 180 degree, between from about 60 degree to about 90 degree,
between from about 45 degree to about 120 degree, between from
about 60 degree to about 120 degree, between from about 90 degree
to about 120 degree, between from about 90 degree to about 180
degree, or between from about 120 degree to about 180 degree.
[0095] FIG. 7 shows the size and shape of stabilization arches for
the stent component in the expanded configuration according to some
embodiments of the disclosure. The .alpha.4 and .alpha.5 angles
represent the offset angle from a longitudinal axis of the
stabilization arches of the forth section of the stent in the
expanded configuration. If the stabilization arches are directed
away from the center of the stent, the .alpha.4 angle is used. If
the stabilization arches are directed toward from the center of the
stent, the .alpha.5 angle is used.
[0096] The .alpha.4 angle is preferably between from about 0 degree
to about 60 degree (e.g., about 5 degree, about 10 degree, about 15
degree, about 20 degree, about 25 degree, about 30 degree, about 35
degree, about 40 degree, about 45 degree, about 50 degree, about 55
degree, and about 60 degree). According to some embodiments, the
.alpha.4 angle is between from about 20 degree to about 60 degree,
between from about 30 degree to about 60 degree, between from about
40 degree to about 60 degree, between from about 45 degree to about
60 degree, between from about 30 degree to about 50 degree, between
from about 30 degree to about 45 degree, between from about 20
degree to about 40 degree, or between from about 15 degree to about
45 degree.
[0097] The .alpha.5 angle is preferably between from about 0 degree
to about 20 degree (e.g., about 5 degree, about 10 degree, about 15
degree, and about 20 degree). According to some embodiments, the
.alpha.5 angle is between from about 5 degree to about 20 degree,
between from about 10 degree to about 20 degree, between from about
15 degree to about 20 degree, between from about 0 degree to about
15 degree, between from about 0 degree to about 10 degree, between
from about 5 degree to about 15 degree, between from about 10
degree to about 15 degree, or between from about 10 degree to about
20 degree.
[0098] FIG. 7 also shows the length of the first section of the
stent component H2, the length of the combined second section and
optional third section of the stent component H3, and the length of
the forth section of the stent component H1. H2 is as described
above.
[0099] Preferably, the length of the combined second section and
optional third section of the stent component H3 is between about 3
to about 50 mm (e.g., about 3 mm, about 4 mm, about 5 mm, about 6
mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm,
about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 20 mm,
about 22 mm, about 24 mm, about 25 mm, about 26 mm, about 28 mm,
about 30 mm, about 32 mm, about 34 mm, about 36 mm, about 38 mm,
about 40 mm, about 42 mm, about 44 mm, about 45 mm, about 46 mm,
about 48 mm, and about 50 mm). The length of the first conical
section H3 may been adjusted depending on the intended application
of the stent of stent-valve. For example, the length of the first
conical section H3 may range from about 3 to about 40 mm, about 3
to about 30 mm, about 3 to about 20 mm, about 3 to about 10 mm,
about 10 to about 50 mm, about 10 to about 40 mm, about 10 to about
30 mm, about 10 to about 20 mm, about 15 to about 50 mm, about 15
to about 40 mm, about 15 to about 30 mm, about 20 to about 50 mm,
about 20 to about 40 mm, about 20 to about 30 mm, about 15 to about
50 mm, about 25 to about 50 mm, about 30 to about 50 mm, about 40
to about 50 mm, about 15 to about 40 mm, about 25 to about 40 mm,
or about 30 to about 40 mm. According to some embodiments of the
stent component, the third section of the stent component is not
used. Thus, H3 would be the same as H1, described above.
[0100] Preferably, the length of the forth section and of the stent
component H4 is between about 5 to about 50 mm (e.g., about 5 mm,
about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about
11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 20
mm, about 22 mm, about 24 mm, about 25 mm, about 26 mm, about 28
mm, about 30 mm, about 32 mm, about 34 mm, about 36 mm, about 38
mm, about 40 mm, about 42 mm, about 44 mm, about 45 mm, about 46
mm, about 48 mm, and about 50 mm). The length of the first conical
section H4 may been adjusted depending on the intended application
of the stent of stent-valve. For example, the length of the first
conical section H4 may range from about 5 to about 40 mm, about 5
to about 30 mm, about 5 to about 20 mm, about 5 to about 10 mm,
about 10 to about 50 mm, about 10 to about 40 mm, about 10 to about
30 mm, about 10 to about 20 mm, about 15 to about 50 mm, about 15
to about 40 mm, about 15 to about 30 mm, about 20 to about 50 mm,
about 20 to about 40 mm, about 20 to about 30 mm, about 15 to about
50 mm, about 25 to about 50 mm, about 30 to about 50 mm, about 40
to about 50 mm, about 15 to about 40 mm, about 25 to about 40 mm,
or about 30 to about 40 mm.
[0101] Using the dimensions described above (i.e., D1, D2, D3, H1,
H2, H3, H4, .alpha.1, .alpha.2, .alpha.3, and .alpha.4), the stent
components of the stent-valves according to some embodiments of the
present disclosure may be classified into different categories of
sizes, such as small, medium, and large. Thus, according to some
embodiments, the stent components (or stent valves) may be sized as
small, medium, and large according the following table.
TABLE-US-00001 Small Medium Large D1 [mm] .sup. 26-31 .sup. 27-32
.sup. 28-33 D2 [mm] .sup. 20-25 .sup. 21-26 .sup. 22-27 D3 [mm]
.sup. 26-32 .sup. 27-33 .sup. 28-34 H1 [mm] .sup. 4-8 .sup. 4-8
.sup. 4-8 H2 [mm] .sup. 7-11 .sup. 8-12 .sup. 9-13 H3 [mm] .sup.
11-15 .sup. 13-17 .sup. 15-19 H4 [mm] .sup. 14-22 .sup. 15-23 .sup.
16-24 .alpha. 1 45.degree.-65.degree. 45.degree.-65.degree.
45.degree.-65.degree. .alpha. 2 15.degree.-25.degree.
15.degree.-25.degree. 15.degree.-25.degree. .alpha. 3
45.degree.-65.degree. 45.degree.-65.degree. 45.degree.-65.degree.
.alpha. 4 5.degree.-15.degree. 5.degree.-15.degree.
5.degree.-15.degree.
[0102] FIG. 8 shows a mating coupling between the attachment
elements 316 of the stent and a stent-holder of a delivery device,
according to some embodiments of the present disclosure. As shown,
at least one, and preferably a plurality or all of the attachment
elements may include a crochet-like configuration that engages, for
example, a groove or other opening within the stent holder. Such
attachment elements may be formed generally in the shape of a bent,
or curved angled member (e.g., an "L" or "" like shape). In some
embodiments, such attachment elements may be a hook (e.g., a "J"
like shape). In the embodiment illustrated in FIG. 8, the
attachment element may be provided in an angled shape, for example,
that extends from the body of the stent inwardly toward a central,
longitudinal axis of the stent. The opening in the stent holder
(e.g., groove) may allow for a safe release of the stent upon
rotation of the delivery system (e.g., a portion, all or members
thereof--e.g., rotation of the stent holder). For example, when
rotating the delivery system/stent holder, the end of the
attachment element slides onto the surface "S" and is thereby
forced, according to some embodiments, to disengage the stent
holder when reaching the edge "E".
[0103] In some embodiments, multiple fixation elements (e.g., 2 or
more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or
more, 9 or more, 10 or more, 11 or more, 12 or more, 13 or more, 14
or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or
more, 20 or more, etc. or 2 to 5, 2 to 10, 2 to 20, 2 to 30, 2 to
40, etc.) may be provided for holding the stent onto a catheter
whereas a matching/complimentary element (e.g., stent holder with
pins) may be attached to the catheter. The design of the multiple
fixation elements (e.g., forming "holes") may allow for the
fixation of the stent onto the catheter only when the stent is
crimped (see e.g., FIG. 9). The fixation may release automatically
when the stent starts to expand. That is, the shape of the stent in
the unexpanded state is designed to have holes or free areas that
can be used to couple the stent with a stent holder. When the stent
is expanded, the expanded configuration is absent suchs holes or
free spaces and thus the stent automatically becomes uncoupled or
releases from the stent holder upon expansion.
[0104] It has been observed in vivo that the design of the stent
component allows for self-positioning of the replacement valve
under diastolic pressure. Once delivered slightly above the aortic
annulus, the stent-valve migrates toward the left ventricle due to
the forces caused by the diastolic pressure until it reaches a
stable position given by the shape/radial force of the anchoring
crown (conically shaped section 2) and the compliance of the aortic
annulus (FIG. 13).
[0105] For example, with respect to some embodiments of the
disclosure, and with reference to FIG. 1A, the stent-valve may be
released such that at least a portion of section 102 of the stent
component is released at the native valve annulus (e.g., release
position). In some preferred embodiments, the release of the stent
valve in the release position preferably comprises a full release
of the stent valve (i.e., the stent-valve is fully released from
the delivery system). Accordingly, subsequent beating of the heart
after release results in the stent-valve sliding into a final
position, which preferably is the groove formed between stent
component sections 102 and 104. The distance between the release
position and the final position, which may be in reference to
either locations at the implantation site (e.g., within the
lumen/heart) and/or locations on the stent component, may comprise
a predetermined range, which may include: between about 3 mm and
about 20 mm, between about 7 mm to about 11 mm, between about 8 mm
to about 12 mm, and between about 9 mm to about 13 mm.
[0106] While preferred embodiments are directed toward releasing
the stent-valve as described above (e.g., paragraph [00105]) at a
release location on stent component section 102, in still other
embodiments, and with reference to FIG. 1A, the stent-valve may be
released (which according to some embodiments, is a full release
from the stent-valve delivery system) such that at least a portion
of section 104 of the stent component is released at the native
valve annulus (e.g., release position), and subsequent beating of
the heart after release results in the stent-valve sliding into a
final position which preferably is the groove portion (as indicated
above) between sections 104 and 102. Accordingly, a range of
distances between release locations and final positions, which may
be in reference to either locations at the implantation site (e.g.,
within the lumen/heart) and/or locations on the stent component,
may be between about 4 mm and 8 mm.
[0107] In some embodiments, a valved-sent delivery system, and
method for delivering the valved-stent to an implantation site are
provided in which the valved-sent is expanded at the implantation
site in a stepwise manner (for example) from its distal end towards
its proximal end. For example, a release procedure for causing
expansion of a valved-stent may involve pulling back a sheath
element on a catheter delivery device. The sheath element, in such
an embodiment, constrains the valved-sent toward a section of the
heart (for example, the left ventricle of the heart). According to
such a procedure, there may be no interaction of the delivery
system with the anatomy of the ascending aorta/aortic arch. For
example, the sheath constraining the valved-stent, and the tip of
the delivery system may not be required to enter the aortic arch
during the release procedure, which is beneficial since such entry
potentially can cause a bending moment acting onto the valved-stent
and result in inaccurate positioning of the valved-stent (e.g.,
tilting).
Cardiac Stent Valve Delivery System
[0108] Some embodiments of the present disclosure provide a cardiac
stent-valve delivery system that includes an inner assembly and an
outer assembly. The inner assembly may include a guide wire lumen
(e.g., polymeric tubing) and a stent bolder for removable
attachment to a stent-valve. The outer assembly may include a
sheath. The inner member and the outer member may be co-axially
positioned and slidable relative to one another in order to
transition from a closed position to an open position, such that in
the closed position the sheath encompasses the stent-valve still
attached to the stent holder and thus constrains expansion of the
stent-valve. In the open position, the outer sheath may not
constrain expansion of the stent-valve and thus the stent-valve may
detach from the stent holder and expand to a fully expanded
configuration.
[0109] In some embodiments, the inner assembly of the delivery
device may include a fluoroscopic marker fixed to the guide wire
lumen distal of the stent holder.
[0110] In some embodiments, the diameter of the outer assembly of
the delivery device varies over its longitudinal axis.
[0111] In still other embodiments, the delivery system comprises a
rigid (e.g., stainless steel) shaft in communication with a
proximal end of the guide wire lumen.
[0112] In some embodiments, the delivery system comprises a luer
connector in communication with the rigid shaft.
[0113] FIG. 14A shows a delivery system 550 for distal-to-proximal
expansion of a stent-valve (i.e., section 108 to section 102--see
FIG. 1), according to some embodiments of the present disclosure.
In some embodiments of the delivery system, the system 550 may
include an inner member 552 and an outer member 554 (e.g., sheath)
which are co-axially positioned and slidable one against the other.
The inner member 552 may comprise tubing 568 (e.g., polymeric
tubing) which serves as a guide wire lumen and on which at least
one of (and preferably several or all) a tip 556, a fluoroscopic
marker 558, and a stent-holder 560 are affixed (e.g., bonded). The
polymeric tubing may be reinforced proximally with a rigid (e.g.,
stainless steel) shaft. A luer connector 562 affixed to a stainless
steel shaft 564 to allow flushing of the guide wire lumen with
saline (for example). The outer member 554 may comprise a distally
arranged sheath which may be used to constrain the stent in a
closed/contracted (e.g., substantially non-expanded) configuration.
Proximally, the sheath may be fixed to a hemostasis valve 566 to
allow the flushing of the annular space between the inner and outer
members with saline (for example). In some embodiments, the
diameter of the outer member may vary over its longitudinal
direction (e.g., smaller diameter proximally to decrease the
bending stiffness of the delivery system). In some embodiments, the
deployment of the stent-valve may occur by holding the inner member
at the level of the stainless steel shaft with one hand and the
outer member at the level of the hemostasis valve with the other
hand. Then, upon positioning of the replacement valve (e.g., under
fluoroscopic control), the outer member is pulled back with the
inner member being kept at its original position, until the stent
is fully deployed.
[0114] FIG. 14B shows the size and shape of delivery system
according to some embodiments. Ds refers to the stent sleeve
diameters, which are the inner and outer sleeve diameters. The
inner diameter of the stent sleeve is preferably from between about
4 to about 14 mm (e.g., about 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm,
10 mm, 11 mm, 12 mm, 13 mm, or 14 mm). The outer diameter of the
stent sleeve is preferably from between about 5 to about 15 mm
(e.g., about 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13
mm, 14 mm, or 15 mm).
[0115] Ls refers to the stent sleeve length. The stent sleeve
length is preferably from between about 20 mm to about 120 mm
(e.g., about 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 50 mm, 60 mm, 70
mm, 80 mm, 90 mm, 100 mm, 110 mm, or 120 mm). According to some
embodiments, the stent sleeve length is between from about 20 mm to
about 100 mm, about 20 mm to about 80 mm, about 20 mm to about 60
mm, about 20 mm to about 40 mm, about 40 mm to about 120 mm, about
60 mm to about 120 mm, about 80 mm to about 120 mm, about 100 mm to
about 120 mm, about 40 mm to about 100 mm, or about 60 mm to about
100 mm.
[0116] Lu refers to the usable length. The usable length is
preferably from between about 150 mm to about 500 mm (e.g., about
150 mm, 175 mm, 200 mm, 225 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450
mm, or 500 mm). According to some embodiments, the usable length is
between from about 150 mm to about 450 mm, about 150 mm to about
400 mm, about 150 mm to about 350 mm, about 150 mm to about 300 mm,
about 150 mm to about 250 mm, about 200 mm to about 500 mm, about
300 mm to about 500 mm, about 350 mm to about 500 mm, about 400 mm
to about 500 mm, about 200 mm to about 400 mm, or about 300 mm to
about 400 mm.
[0117] Lt refers to the total length. The total length is
preferably from between about 200 mm to about 1000 mm (e.g., about
200 mm, 225 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550
mm, 600 mm, 650 mm, 700 mm, 750 mm, 800 mm, 850 mm, 900 mm, 950 mm,
or 1000 mm). According to some embodiments, the total length is
between from about 200 mm to about 900 mm, about 200 mm to about
800 mm, about 200 mm to about 700 mm, about 200 mm to about 600 mm,
about 200 mm to about 500 mm, about 200 mm to about 400 mm, about
200 mm to about 300 mm, about 300 mm to about 1000 mm, about 400 mm
to about 1000 mm, about 500 mm to about 1000 mm, about 600 mm to
about 1000 mm, about 700 mm to about 1000 mm, about 800 mm to about
1000 mm, about 900 mm to about 1000 mm, or about 300 mm to about
800 mm.
[0118] FIGS. 15A-D illustrate an exemplary embodiment of a method
of implanting a stent-valve within a human heart according to some
embodiments of the present disclosure (e.g., an aortic valve
replacement). Accordingly, FIG. 15A shows the initial, partial
release of the stent 1500, in which the radiopaque 1512 marker
positioned on one of the arches of stent section 1508 (see FIG. 1),
for example, is released distally from the outer sheath. By
tracking the radiopaque marker 1512, the delivery system 1550 may
then be rotated as necessary in order to orient the stent 1500
appropriately with respect to, for example, the coronary arteries
(e.g., orienting the stent-valve such that the commissures do not
face the coronary arteries). More specifically, prior to full
release of the stent 1500, the delivery system 1550 may be rotated
in order to cause the radiopaque marker 1512 to be placed between
the osteum of the left and right coronary arteries.
[0119] FIG. 15B shows a further, but still partial release of the
stent 1500, in which the larger, orientation arches 1509 of stent
section 1508 are released from the outer sheath 1554 and placed
into contact with the aorta (for example).
[0120] FIG. 15C illustrates an example of yet a further, still
partial release but almost fully released, illustration of the
stent release, in which the first conical crown of stent section
1504 is released from the outer sheath 1554 for engagement with the
native valve leaflets 1580.
[0121] FIG. 15D illustrates an example of a full release of the
stent, in which the second conical crown of stent section 1502
(i.e., the proximal section of the stent; see FIG. 1) is released
from the outer sheath 1554 for engagement with the annulus/inflow
tract.
Medical Uses
[0122] According to some embodiments, cardiac stent-valves are
provided as cardiac replacement valves. There are four valves in
the heart that serve to direct the flow of blood through the two
sides of the heart in a forward direction. On the left (systemic)
side of the heart are: 1) the mitral valve, located between the
left atrium and the left ventricle, and 2) the aortic valve,
located between the left ventricle and the aorta. These two valves
direct oxygenated blood coming from the lungs through the left side
of the heart into the aorta for distribution to the body. On the
right (pulmonary) side of the heart are: 1) the tricuspid valve,
located between the right atrium and the right ventricle, and 2)
the pulmonary valve, located between the right ventricle and the
pulmonary artery. These two valves direct de-oxygenated blood
coming from the body through the right side of the heart into the
pulmonary artery for distribution to the lungs, where it again
becomes re-oxygenated to begin the circuit anew.
[0123] Problems that can develop with heart valves consist of
stenosis, in which a valve does not open properly, and/or
insufficiency, also called regurgitation, in which a valve does not
close properly. In addition to stenosis and insufficiency of heart
valves, heart valves may need to be surgically repaired or replaced
due to certain types of bacterial or fungal infections in which the
valve may continue to function normally, but nevertheless harbors
an overgrowth of bacteria on the leaflets of the valve that may
embolize and lodge downstream in a vital artery. In such cases,
surgical replacement of either the mitral or aortic valve
(left-sided heart valves) may be necessary. Likewise, bacterial or
fungal growth on the tricuspid valve may embolize to the lungs
resulting in a lung abscess. In such cases replacement of the
tricuspid valve even though no tricuspid valve stenosis or
insufficiency is present.
[0124] According to some embodiments, there is provided a method
for replacing a worn or diseased valve comprising transapically
implanting a replacement valve, wherein the replacement valve is a
stent-valve of the present disclosure. Accordingly, the replacement
valve comprises a valve component and a stent component, wherein
the valve component is connect to the stent component.
[0125] The stent component preferably comprises a longitudinal axis
and preferably has four sections. The first section, as above,
includes a substantially conical shape having a narrow end, a broad
end and a predetermined first height. The second section, as above,
includes a substantially conical shape having a narrow end, a broad
end and a predetermined second height. The center of each of the
first section and the second section are preferably arranged to
align substantially with the longitudinal axis. The narrow ends of
the first section and second section are preferably arranged to
meet forming an annular groove to receive the annulus of worn or
diseased cardiac valve at an implantation site of the heart. The
first height of the first section is preferably greater than the
second height of the second section. Upon implantation, the
replacement valve is positioned so that the annular groove receives
the annulus of the worn or diseased cardiac valve.
[0126] As the stent-valves of the present disclosure are designed
to be self-positioning under diastolic pressure (i.e., permissible
in vivo migration), the placement of the stent-valve may be
upstream of the annulus, whereupon when the stent-valve will be
locked into position once the annular groove of the stent component
receives the annulus. Thus, according to some embodiments, methods
are provided for implanting a replacement valve into a heart of a
mammal comprising delivering a replacement valve to an implantation
site of the heart of the mammal. The implantation site preferably
comprises a release location and a final location; and the release
location is spaced apart from the final location (and according to
some embodiments, the spacing comprises a predetermined distance),
and in some embodiments, in a blood upflow direction. Releasing the
replacement valve at the release location, the replacement valve is
able to slide into the final location, generally upon at least one
beat of the heart subsequent to the replacement valve being
released at the release location.
[0127] According to some embodiments, the methods provides that
when the replacement valve sliding into the final location, the
replacement valve is substantially positioned to the final
location.
[0128] In some embodiments of the present disclosure, a method is
provided for replacing an aortic valve within a human body. A
stent-valve may be covered with a sheath in order to maintain the
stent-valve in a collapsed configuration. The stent-valve may then
may be inserted in the collapsed configuration into the human body
without contacting the ascending aorta or aortic arch. The
stent-valve may be partially expanded by sliding the sheath towards
the left ventricle of the heart. This sliding of the sheath towards
the left ventricle may cause expansion of a distal end of the
stent-valve while the proximal end of the stent-valve remains
constrained by the sheath. The sheath may be further slid towards
the left ventricle of the heart in order to cause full expansion of
the stent-valve. In some embodiments, the stent-valve may be
recaptured prior to its full expansion by sliding the sheath in the
opposite direction.
[0129] In some embodiments, a method for cardiac valve replacement
is provided that includes releasing a distal end of a stent-valve
from a sheath, where the distal end includes a radiopaque marker
positioned thereon. The stent-valve is rotated, if necessary, to
orient the stent-valve appropriately with respect to the coronary
arteries (e.g., to prevent the commissures from facing the coronary
arteries). Arches of the stent-valve are released from the sheath,
in order to cause the arches to contact the aorta. A first conical
crown of the stent-valve is released from the sheath, in order to
cause the first conical crown to contact the native valve leaflets.
A second crown of the stent-valve is released from the sheath, in
order to cause the second crown to contact an annulus/inflow tract.
The second crown may be the proximal section of the stent-valve
such that releasing the second crown causes the stent-valve to be
fully released from the sheath.
[0130] According to some embodiments, a replacement valve for use
within a human body is provided, where the replacement valve
includes a valve component and a stent component. The stent
component also may be used without a connected valve as a stent.
The stent devices of the present disclosure may use used to
mechanically widen a narrowed or totally obstructed blood vessel;
typically as a result of atherosclerosis. Accordingly, the stent
devices of the present disclosure may use used is angioplasty
procedures. These include: percutaneous coronary intervention
(PCI), commonly known as coronary angioplasty, to treat the
stenotic (narrowed) coronary arteries of the heart found in
coronary heart disease; peripheral angioplasty, performed to
mechanically widen the opening in blood vessels other than the
coronary arteries.
[0131] Thus, it is seen that stent-valves (e.g.,
single-stent-valves and double-stent-valves) and associated methods
and systems for surgery are provided. Although particular
embodiments have been disclosed herein in detail, this has been
done by way of example for purposes of illustration only, and is
not intended to be limiting with respect to the scope of the
appended claims, which follow. In particular, it is contemplated by
the applicant that various substitutions, alterations, and
modifications may be made without departing from the spirit and
scope of invention as defined by the claims. Other aspects,
advantages, and modifications are considered to be within the scope
of the following claims. The claims presented are representative of
the inventions disclosed herein. Other, unclaimed inventions are
also contemplated. The applicant reserves the right to pursue such
inventions in later claims.
* * * * *