U.S. patent application number 12/401276 was filed with the patent office on 2009-07-02 for stent-valves for valve replacement and associated methods and systems for surgery.
Invention is credited to Stephane DELALOYE, Ludwig K. VON SEGESSER.
Application Number | 20090171447 12/401276 |
Document ID | / |
Family ID | 38924490 |
Filed Date | 2009-07-02 |
United States Patent
Application |
20090171447 |
Kind Code |
A1 |
VON SEGESSER; Ludwig K. ; et
al. |
July 2, 2009 |
STENT-VALVES FOR VALVE REPLACEMENT AND ASSOCIATED METHODS AND
SYSTEMS FOR SURGERY
Abstract
Stent-valves (e.g., single-stent-valves and
double-stent-valves), associated methods and systems for their
delivery via minimally-invasive surgery, and guide-wire compatible
closure devices for sealing access orifices are provided.
Inventors: |
VON SEGESSER; Ludwig K.;
(Lausanne, CH) ; DELALOYE; Stephane; (Bulach,
CH) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Family ID: |
38924490 |
Appl. No.: |
12/401276 |
Filed: |
March 10, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11700922 |
Dec 21, 2006 |
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12401276 |
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60753071 |
Dec 22, 2005 |
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60755590 |
Dec 29, 2005 |
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60843181 |
Sep 7, 2006 |
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Current U.S.
Class: |
623/1.24 ;
623/1.15; 623/1.36 |
Current CPC
Class: |
A61F 2002/9505 20130101;
A61F 2/966 20130101; A61F 2220/0075 20130101; A61F 2230/0078
20130101; A61F 2210/0014 20130101; A61B 2017/00606 20130101; A61B
17/12131 20130101; A61F 2/2418 20130101; A61F 2/2427 20130101; A61F
2002/9534 20130101; A61B 2017/00623 20130101; A61F 2/2433 20130101;
A61F 2210/0042 20130101; A61F 2220/0083 20130101; A61F 2250/001
20130101; A61F 2/2436 20130101; A61F 2230/0013 20130101; A61B
2017/12095 20130101; A61F 2/90 20130101; A61F 2250/0039 20130101;
A61F 2/2472 20130101; A61B 17/0057 20130101; A61B 17/12031
20130101; A61F 2/243 20130101; A61F 2220/0016 20130101; A61F 2/9522
20200501; A61F 2002/9511 20130101; A61F 2230/0067 20130101; A61F
2002/9665 20130101; A61F 2250/006 20130101 |
Class at
Publication: |
623/1.24 ;
623/1.15; 623/1.36 |
International
Class: |
A61F 2/06 20060101
A61F002/06 |
Claims
1. A replacement valve for use within a human body comprising: a
valve component; a stent component comprising a first section, a
second section for housing the valve component, and a third
section, wherein the third section comprises at least one
attachment element configured for removable attachment to a
delivery device.
2. The replacement valve of claim 1, wherein the at least one
attachment element comprises a geometric opening configured for
removable attachment to a complimentary element of the delivery
device.
3. The replacement valve of claim 1, wherein the at least one
attachment element comprises a wire, hook, or strap configured for
removable attachment to a complimentary element of the delivery
device.
4. The replacement valve of claim 1, wherein the at least one
attachment element comprises at least two attachment elements.
5. The replacement valve of claim 1, wherein the at least one
attachment element comprises at least three attachment
elements.
6. The replacement valve of claim 1, wherein the at least one
attachment element comprises at least six attachment elements.
7. The replacement valve of claim 1, wherein the stent component
comprises a lattice structure comprising: at least one commissural
post; and the at least one attachment element.
8. The replacement valve of claim 7, wherein the lattice structure
further comprises at least one supporting element for connecting
the at least one commissural post to the at least one attachment
element.
9. The replacement valve of claim 1, wherein the at least one
attachment element projects at least partially inwardly toward a
center axis of the stent component.
10. The replacement valve of claim 1, wherein the third section has
a diameter that is less than a diameter of the second section.
11. A replacement valve for use within a human body comprising: a
valve component; and a stent component comprising: a first section
comprising a fixation element; a second section configured to house
the valve component; and a third section comprising at least one
attachment element.
12. The replacement valve of claim 11, wherein the fixation element
comprises an annular groove.
13. The replacement valve of claim 12, wherein the annular groove
is formed from a plurality of independently bendable elements,
wherein each bendable element comprises a bending deformation the
location of which is determined by the lengths of an attached pair
of struts.
14. The replacement valve of claim 11, wherein the attachment
element comprises a wire that forms an opening, hook, or strap.
15. The replacement valve of claim 11, wherein the second region
comprises at least one locking element protruding outwardly from an
outer surface of the second region.
16. A replacement valve for use within a human body comprising: a
valve component; and at least two stent components affixed to one
another comprising: a first section comprising a first cone or
crown and a second stent structure collectively forming a fixation
element; and a second section configured to house the valve
component; wherein the at least two stent components further
comprise a third section comprising at least one attachment element
for removable attachment to a delivery device; and at least one of
the first cone or crown and the second cone or crown has
cross-section substantially in the shape of a pyramid.
17. A method for delivering a cardiac stent-valve to an
implantation site comprising: removably attaching the stent-valve
to a delivery device; delivering the stent-valve to the
implantation site in a collapsed configuration; partially
proximally expanding the stent-valve while maintaining the
stent-valve attached to the delivery device; and making a
determination with respect to the stent-valve when the stent-valve
is in the partially-expanded configuration.
18. The method of claim 17, wherein the making a determination
comprises determining whether the stent-valve is positioned
correctly at the implantation site.
19. The method of claim 18, further comprising returning the
stent-valve to the collapsed configuration and repositioning the
stent-valve when the stent-valve is not positioned correctly at the
implantation site.
20. The method of claim 17, wherein the making a determination
comprises determining whether a valve component of the stent-valve
is functioning properly.
21. The method of claim 20, wherein determining whether the valve
component is functioning properly comprises testing whether the
valve component will permit sufficient blood-flow.
22. The method of claim 20, further comprising returning the
stent-valve to the collapsed configuration and removing the
stent-valve from a patient's body when the stent-valve is not
functioning properly.
23. The method of claim 17, further comprising causing the
stent-valve to fully expand by causing the stent-valve to detach
from the delivery device, when the making a determination yields a
positive response.
24. The method of claim 17, wherein the delivering the stent-valve
to the implantation site comprises delivering the stent-valve to
the heart for replacement of a cardiac valve, wherein the
delivering further comprises: accessing a patient's body through an
intercostal space; and penetrating the left ventricle at the apex
of the heart.
25. The method of claim 24, wherein the accessing comprises
accessing the patient's body through a fifth intercostal space.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S.
Provisional Patent Application Nos. 60/753,071, filed Dec. 22,
2005, 60/755,590, filed Dec. 29, 2005, and 60/843,181, filed Sep.
7, 2006, each of which is incorporated by reference herein in its
entirety.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention relate to stent-valves,
associated methods and systems for their delivery via
minimally-invasive surgery, and guide-wire compatible closure
devices for sealing access orifices.
BACKGROUND OF THE INVENTION
[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). Despite their
invasiveness, these surgical approaches may be reasonably safe for
a first intervention. However, tissue adherences resulting from the
first surgery may increase the risks (e.g., death) associated with
subsequent valve replacement surgeries. See Akins et al., "Risk of
Reoperative Valve Replacement for Failed Mitral and Aortic
Bioprostheses", Ann Thorac Surg 1998; 65:1545-52; and Weerasinghe
et al., "First Redo Heart Valve Replacement--A 10-Year Analysis",
Circulation 1999; 99:655-658; each of which is incorporated by
reference herein in its entirety.
[0004] Synthetic valves and biological valves have been used for
cardiac valve replacement with varying results. Synthetic valves
rarely fail but require life-long anti-coagulant treatment to
prevent blood from clotting (thrombosis) in and around the
replacement valve. Such anti-coagulant treatment significantly
limits patients' activities and can cause various other
complications. Biological valves do not require such
anti-coagulation treatment but typically fail within 10-15 years.
Thus, to limit the need for and risks associated with re-operation
on failed biological valves, traditionally only patients with less
than about 10-15 years to live have received biological valve
replacements. Patients with longer life expectancies have received
synthetic valves and anti-coagulant treatment.
[0005] Attempts have been made to develop less-invasive surgical
methods for cardiac valve replacement. These surgical methods,
referred to as percutaneous heart valve replacement therapies
(PHVT), use a catheter to deliver a replacement valve to an
implantation site using the patient's vascular system. These PHVT
attempts have various shortcomings, including their inability to
ensure proper positioning and stability of the replacement valve
within the patient's body.
[0006] Conventional closure devices for closing access orifices are
also lacking in several respects, including the looseness of their
fit which can cause bleeding after surgery. These closure devices
also lack a central lumen, which renders them incompatible with
guide wire delivery systems. One such conventional closure device
is described in Malgorzata Pawelec-Wojtalik, "Closure of left
ventricle perforation with the use of muscular VSD occluder",
European Journal of Cardio-Thoracic Surgery 27 (2005) 714-716,
which is incorporated by reference herein in its entirety.
[0007] In view of the foregoing, it would be desirable to provide
improved methods, systems, and devices for cardiac valve
replacement.
SUMMARY OF THE INVENTION
[0008] Some embodiments of the present invention are directed to
systems, methods, and devices for cardiac valve replacement. For
example, these methods, systems, and devices may be applicable to
the full range of cardiac-valve therapies including the replacement
of failed aortic, mitral, tricuspid, and pulmonary valves. In some
embodiments, the present invention may facilitate a surgical
approach whereby surgery is performed 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.
[0009] Stent-valves according to some embodiments of the present
invention may include a valve component and at least one stent
component. The valve component may include a biological or
synthetic (e.g., mechanical) valve and/or any other suitable
material(s). The stent component may include a first section (e.g.,
proximal section), a second section configured to house the valve
component, and a third section (e.g., distal section). The stent
and valve components may be capable of at least two configurations:
a collapsed configuration (e.g., during delivery) and an expanded
configuration (e.g., after implantation).
[0010] In some embodiments, the first section of the stent valve
may include a fixation element. Such a fixation element may
include, for example, an annular groove for securing the
stent-valve in place at an implantation site. When the stent-valve
includes a single stent ("single-stent-valve"), the annular groove
may be configured to receive the annulus of the valve in need of
replacement. When the stent-valve includes two stents
("double-stent-valve"), the annular groove of the first stent
component may be configured for matable attachment to a
complimentary annular projection of a second stent component (i.e.,
a positioning stent). In turn, the second stent component may be
anchored at the implantation site, for example, to the valve in
need of replacement and/or adjoining structures.
[0011] Alternatively or additionally, in some embodiments the third
section of the stent component may include at least one attachment
element. Each attachment element of the stent-valve may include,
for example, a geometrical opening (e.g., circular or ovular),
hook, or strap configured for removable attachment to a
complimentary structure of a delivery device. In addition, each
attachment element may correspond to all or a portion of a
commissural post, to which a commissure between two valve leaflets
may be attached. The attachment element(s) may allow the
stent-valve to be partially expanded within a patient's body while
the stent-valve remains attached to the delivery device. This may
allow the stent-valve to be returned to a collapsed configuration
and repositioned within the patient's body when it is determined
that fully expanding the stent-valve would cause the stent-valve to
be installed incorrectly. Alternatively or additionally, this may
allow the stent-valve to be returned to the collapsed configuration
and removed from the patient's body when it is determined that the
stent-valve is not functioning properly (e.g., not permitting
sufficient flow). In some embodiments, the stent-valve may include
one attachment element. In other embodiments, the stent-valve may
include at least two, three, six, or any other suitable number of
attachment elements. In some embodiments, the fully-expanded stent
diameter in the region of the attachment element(s) may be smaller
than the diameter of the region that houses an associated valve.
This may reduce the risk of injury to the patient's body (e.g.,
perforation of the aorta) from the attachment elements and/or make
it easier to affix the attachment elements to the complimentary
structure of the delivery device.
[0012] In some embodiments, the stent component of the stent-valve
may include a lattice structure with a plurality of cells. The
lattice structure may be formed from, for example, a shape-memory
alloy such as nitinol or any other suitable material(s). The cells
in the lattice structure may be most densely populated in the
section of the stent component that includes the fixation element.
This may provide added support to the fixation element and increase
the stability of the stent-valve. In some embodiments, the lattice
structure may form at least one elongate stem (e.g., commissural
post) that extends distally along the stent component towards the
at least one attachment element. The at least one stem may connect
directly to the at least one attachment element. Alternatively, the
lattice structure may form at least one supporting element for
connecting the at least one stem to the at least one attachment
element. In some embodiments, all of the cells in the lattice
structure may be closed cells, which may facilitate recapture of
the stent-valve from the partially-expanded configuration to the
collapsed configuration.
[0013] Still other embodiments of the present invention are
directed to a method for replacing a valve. A stent-valve is
provided that includes a stent component with an annular groove,
and the stent-valve is secured axially to an annulus of the valve
in need of replacement. In some embodiments, providing a
stent-valve may include suturing a valve component to the stent
component. Alternatively or additionally, providing a stent-valve
may include expanding a valve component within the stent component
in order to form a friction fitting. In some embodiments, providing
a stent-valve may include securing a valve component to the stent
component with a hook-and-loop (e.g., VELCRO.RTM.) fastening
system.
[0014] In other embodiments of the present invention, a method for
replacing a valve is provided whereby a first stent component that
includes an annular element is implanted such that at least a
portion of the first stent component is housed within a valve in
need of replacement. A stent-valve that includes a second stent
component is positioned within the first stent component by matably
attaching a complimentary annular element of the second stent
component to the annular element of the first stent component.
[0015] In still other embodiments of the present invention, a
stent-valve delivery system is provided. A first assembly is
provided that includes an outer sheath and a guide wire tubing. The
delivery system also includes a second assembly including a stent
holder configured for removable attachment to at least one
attachment element of a stent-valve. The stent-valve may be
positioned over the guide wire of the first assembly. The first
assembly and the second assembly may be configured for relative
movement with respect to one another in order to transition from a
closed position to an open position. In the closed position, the
outer sheath may encompass the stent-valve still attached to the
stent holder and thus constrain 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 first assembly and the second
assembly may be configured to transition from the closed position,
to a partially-open position, to the open position. In the
partially-open position, the stent-valve may expand partially but
not detach from the stent holder because the outer sheath may still
encompass the at least one attachment element of the stent-valve
and the stent holder. When the stent-valve is in the
partially-expanded configuration, it may be determined whether the
stent-valve will be positioned correctly if the stent-valve is
expanded to the fully expanded configuration. Alternatively or
additionally, the functionality of the stent-valve may be tested
(e.g., to determine whether the stent-valve will permit sufficient
blood-flow) when the stent-valve is in the partially-expanded
configuration.
[0017] In some embodiments, the stent-valve delivery system may
include at least one balloon (e.g., proximal to the stent-valve or
other stent to be delivered) configured to cause expansion of the
stent-valve or positioning stent upon inflation of the at least one
balloon.
[0018] In some embodiments, the stent-valve delivery system may
include a push handle that causes the relative movement of the
first assembly and the second assembly. Alternatively, the
stent-valve delivery system may include a screw mechanism for
translating rotational movement of a handle into the relative
movement of the first assembly and the second assembly.
[0019] In some embodiments, the stent-valve delivery system may
include an integrated introducer within which the first assembly
and the second assembly are positioned during delivery of the
stent-valve to an implantation site. The integrated introducer may
be configured to remain within a patient's body even after the
first assembly and the second assembly are removed, for example, to
allow for the introduction of an occluder.
[0020] In some embodiments, after expansion of the stent-valve to
the fully expanded configuration, the delivery system may be
configured to return to the closed position by passing the second
assembly through the stent-valve towards a distal end of the first
assembly.
[0021] Still other embodiments of the present invention are
directed to a method for delivering a stent-valve to an
implantation site whereby the stent-valve is removably attached to
a delivery device and the stent-valve is delivered to the
implantation site in a collapsed configuration. The stent-valve may
be partially expanded while maintaining the stent-valve attached to
the delivery device. A determination with respect to the
stent-valve may be made when the stent-valve is in the
partially-expanded configuration. When the determination yields a
positive response, the stent-valve may be expanded to its fully
expanded configuration by causing the stent-valve to detach from
the delivery device.
[0022] In one particular embodiment, it may be determined whether
the stent-valve is positioned correctly at the implantation site.
The stent-valve may be returned to the collapsed configuration and
repositioned when the stent-valve is not positioned correctly at
the implantation site.
[0023] Alternatively or additionally, it may be determined whether
a valve component of the stent-valve is functioning properly, for
example, by testing whether the valve component will permit
sufficient blood-flow. The stent-valve may be returned to the
collapsed configuration and removed from a patient's body when the
stent-valve is not functioning properly.
[0024] In some embodiments, delivering the stent-valve to the
implantation site may include delivering the stent-valve to the
heart for replacement of a cardiac valve. The delivery may include
accessing a patient's body through an intercostal space (e.g.,
fifth intercostal space) and penetrating the left ventricle at the
apex of the heart.
[0025] In still other embodiments of the present invention, an
occluder for sealing an orifice in tissue is provided. The occluder
may include a first portion capable of expansion from a collapsed
configuration on a luminal side of the orifice to an expanded
configuration. The occluder also includes a second portion capable
of expansion from a collapsed configuration to an expanded
configuration on a side of the orifice opposite to the luminal
side. The first portion and the second portion may form a central,
hollow channel for housing a guide wire.
[0026] In some embodiments, the occluder may include a connector
for connecting the occluder to a catheter. For example, the
connector may include a hollow screw mechanism for connecting to a
threaded catheter. The occluder may be housed by a second catheter
for delivery to the tissue orifice.
[0027] In some embodiments, the top portion of the occluder may
include a channel sealing mechanism for preventing blood-flow from
the luminal side of the tissue orifice. For example, the channel
sealing mechanism may include a membrane, foam, and/or a valve.
Suitable examples of foam and/or membranous materials include
polyurethane and gelatin.
[0028] In some embodiments, the top portion of the occluder may
include a first material and the bottom portion of the occluder may
include a second material, where the second material may be coarser
than the first material. This may facilitate the formation of scar
tissue on the outer portion and speed the heeling process. For
example, the first and/or second materials may include felt(s)
and/or velour(s) made from Teflon, Dacron, polyurethane,
polydioxanone, polyhydroxybutyrate, and/or other material.
[0029] In other embodiments of the present invention, a method for
sealing an orifice in tissue is provided whereby an expandable and
collapsible occlusion device is connected to a first catheter. The
occlusion device may be inserted into a second catheter in a
collapsed condition. The first catheter and a central channel of
the occlusion device may receive a guide wire. The second catheter
may be positioned in the orifice, such that a first end of the
second catheter is positioned on a luminal side of the orifice.
Relative-movement between the collapsed occlusion device and the
second catheter may be caused in order to move the occlusion device
out of the second catheter. Upon the occlusion device emerging from
the first end of the second catheter, a first portion of the
occlusion device may expand on the luminal side of the orifice.
Upon the occlusion device being completely emerged from the second
catheter, a second portion of the occlusion device may expand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] For a better understanding of the present invention,
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:
[0031] FIG. 1A shows a valve component in an expanded configuration
according to some embodiments of the present invention;
[0032] FIG. 1B shows a valve component in a collapsed configuration
according to some embodiments of the present invention;
[0033] FIG. 2A shows a stent component in an expanded configuration
according to some embodiments of the present invention;
[0034] FIG. 2B shows a single-stent-valve, that includes a stent
component and a valve component, in an expanded configuration
according to some embodiments of the present invention;
[0035] FIG. 2C shows a single-stent-valve a collapsed configuration
according to some embodiments of the present invention;
[0036] FIG. 3A shows a stent component in an expanded configuration
according to some embodiments of the present invention;
[0037] FIG. 3B shows a stent component in a collapsed configuration
according to some embodiments of the present invention;
[0038] FIG. 4 shows a double-stent-valve, that includes two stent
components and a valve component, in an expanded configuration
according to some embodiments of the present invention;
[0039] FIGS. 5A-7B illustrate the use of a single-stent-valve to
replace a failed biological (artificial) valve according to some
embodiments of the present invention;
[0040] FIGS. 8A and 8B show a stent component that includes
attachment elements for securing the stent to a delivery device and
fixation elements for securing the stent at the implantation site
according to some embodiments of the present invention;
[0041] FIG. 8C shows a stent component having a diameter in the
region of the attachment element(s) that is smaller than the
diameter of a stent region that houses an associated valve,
according to some embodiments of the present invention;
[0042] FIG. 8D shows a stent component that includes independently
bendable element(s) for use in positioning/securing the stent to
the geometry/topology at an implantation site according to some
embodiments of the present invention;
[0043] FIG. 8E shows a stent component that includes locking
elements in a crown configuration and a fixation element for
securing the stent at an implantation site according to some
embodiments of the present invention;
[0044] FIG. 8F shows a stent component that includes multiple
struts for carrying a valve component more closely to a region of
the stent component that includes attachment element(s) for
attaching the stent component to a delivery device;
[0045] FIGS. 9A-16 show additional embodiments of stent components
that include attachment elements for securing the stent to a
delivery device and/or fixation elements for securing the stent at
the implantation site according to the present invention;
[0046] FIGS. 17/18, 19, and 20 show additional examples of
double-stent-valves according to some embodiments of the present
invention;
[0047] FIG. 21A shows a stent-valve in the shape of an opposed
double crown according to some embodiments of the present
invention;
[0048] FIGS. 21B-E show views of a double-conical stent in
accordance with some embodiments of the present invention;
[0049] FIGS. 22A-22D show a delivery system for delivering a
self-expanding stent-valve to an implantation site according to
some embodiments of the present invention;
[0050] FIGS. 23A-23D show a delivery system with inflatable
balloon(s) according to some embodiments of the present
invention;
[0051] FIGS. 24A-24D show a delivery system having a proximal outer
shaft with an increased diameter according to some embodiments of
the present invention;
[0052] FIGS. 25A-25C show a delivery system with inflatable
balloon(s) according to some embodiments of the present
invention;
[0053] FIGS. 26A-26C show a delivery system with an integrated
introducer according to some embodiments of the present
invention;
[0054] FIG. 27 is a flowchart of illustrative stages involved in
replacing a failed native or artificial valve according to some
embodiments of the present invention;
[0055] FIGS. 28A-C illustrate the replacement of a failed valve
through the use of a delivery system according to some embodiments
of the present invention;
[0056] FIGS. 29A and 29B show a guide wire compatible occluder for
sealing an access orifice according to some embodiments of the
present invention;
[0057] FIG. 30 shows a guide wire for guiding the delivery of an
occluder and/or stent-valve according to some embodiments of the
present invention;
[0058] FIG. 31 shows a threaded catheter for attachment to and use
in positioning an occluder according to some embodiments of the
present invention;
[0059] FIGS. 32A and 32B show a delivery system for an occluder
according to some embodiments of the present invention; and
[0060] FIGS. 33A and 33B show an occluder positioned within an
access orifice according to some embodiments of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0061] FIGS. 1A-3B show components 100, 200, and 300 for use in
replacing, for example, a failed (e.g., degenerated) aortic valve,
mitral valve, or pulmonary cardiac valve (e.g., in a pediatric
patient) in accordance with some embodiments of the present
invention. More particularly, FIGS. 1A and 1B show a valve
component 100. FIGS. 2A-2C show a stent component 200 for housing
valve component 100. FIGS. 3A and 3B show a stent component 300 for
housing stent component 200 and valve component 100. A device that
includes components 100 and 200 may be referred to as a
single-stent-valve. A device that additionally includes component
300 may be referred to as a double-stent-valve.
[0062] FIG. 4 shows a double-stent-valve 400 that includes valve
component 100, stent component 200, and stent component 300 in
accordance with some embodiments of the present invention.
Double-stent-valve 400 may replace a failed native or artificial
valve. As used herein, a "native valve" refers to a valve naturally
present within a patient's body. A failed native valve may be, for
example, a stenotic valve. An "artificial valve" refers to a
biological or synthetic (e.g., mechanical) valve introduced into
the patient's body through surgery. The implantation site for a
device 400 (or other replacement valve) typically includes at least
a part of the area within the failed valve and/or along at least a
portion of adjacent structure(s). For example, to replace a failed
aortic valve, device 400 may be implanted within the patient's body
such that portion 402 of the device is positioned substantially
entirely within the failed aortic valve. Portion 404 of device 400
may extend along at least a portion of the aorta. Portion 406 of
device 400 may extend into at least a portion of the left ventricle
of the patient's heart.
[0063] Double-stent-valve 400 may be delivered to the implantation
site using any suitable delivery approach. In some embodiments of
the present invention, device 400 may be substantially entirely
assembled from components 100, 200, and 300 outside the patient's
body before device 400 is delivered to the implantation site. In
other embodiments of the present invention, components 100, 200 and
300 of device 400 may be delivered to the implantation site
separately in multiple steps. For example, stent component 300 may
be delivered and installed at the implantation site, followed by
the delivery and installation of stent component 200 and valve
component 100 in one or more separate steps. In one embodiment,
components 100 and 200 may be assembled outside the patient's body
and then delivered and installed within component 300 at the same
time. In another embodiment, stent component 200 may be delivered
and installed within stent component 300, followed by the delivery
and installation of valve component 100 in a separate step.
Additional embodiments of double-stent-valves are described in
connection with FIGS. 17-20.
[0064] In some embodiments of the present invention, a
single-stent-valve (FIG. 2B) that includes valve component 100 and
stent component 200 (but not stent component 300) may be used to
replace a failed native or artificial valve. For example, in one
particular embodiment, the single-stent-valve may replace a failed
biological valve introduced to a patient's body during a prior
valve replacement surgery. Thus, the surgery involving the
single-stent-valve shown in FIG. 2B may be a secondary or
subsequent valve replacement surgery. Although in this embodiment
no new stent component 300 may be introduced to the patient's body,
the single-stent-valve including components 100 and 200 may be
housed by a stent and/or valve remaining at the implantation site
from the prior valve replacement surgery. In some embodiments, at
least a portion of the stent and/or valve from the prior surgery
may be removed before the single-stent-valve is installed at the
implantation site. Additional details regarding the replacement of
a failed biological valve with a single-stent-valve are described
in connection with FIGS. 5A-7B.
[0065] In some embodiments of the present invention, valve
component 100 may be flexible and collapsible such that it can be
collapsed, for example, during delivery via a catheter to the
implantation site. Various embodiments of delivery systems and
surgical approaches for minimally-invasive surgery are described
below in connection with FIGS. 22A-26C. Upon delivery, the valve
component may be at least partially expanded. FIG. 1A is a
perspective view of valve component 100 in an expanded
configuration. FIG. 1B is a perspective view of valve component 100
in a collapsed configuration. As used herein, "collapsed
configuration" and "expanded configuration" refer to a relative
difference in, for example, the diameter and/or any other physical
characteristic(s) of a component (e.g., length, width). For
example, the collapsed valve component shown in FIG. 1B has an
reduced diameter and may or may not have a longer length than the
expanded valve component shown in FIG. 1A.
[0066] Valve component 100 may include a biological material (e.g.,
tanned, untanned, heterologous or autologous), non-biological
material, a synthetic material (e.g., polymer(s) such as
polyurethane and/or silicon(es)), or a combination thereof. In some
embodiments, valve component 100 may include preserved biological
tissue such as, for example, human tissue (e.g., homografts,
autografts of valve tissue) or animal tissue (heterograft or
xenograft valve tissue). In some embodiments, valve component 100
may be a mechanical valve. For example, when valve component 100 is
a biological valve, expansion of valve component 100 from a
collapsed configuration to an expanded may require self-expansion
of an affixed stent component 200. In contrast, a synthetic valve
component 100 may be capable of self-expansion. Valve component 100
may have a shape/form (e.g., length, width, diameter, etc.)
corresponding to that of the intended valve application (e.g.,
tricuspid, pulmonary, mitral or aortic). In FIGS. 1A and 1B, valve
component 100 is a tricuspid valve with three flaps. This
particular configuration may be particularly suitable, for example,
for replacing a failed aortic valve. In other embodiments, valve
component 100 may have any other suitable number of flaps and/or
other physical characteristics (e.g., diameter, length, width,
etc.).
[0067] FIG. 2A is a perspective view of stent component 200 in
accordance with an embodiment of the present invention. As shown in
FIG. 2B, stent component 200 houses valve component 100. In some
embodiments, at least a portion of stent component 200 may be
substantially cylindrical in shape. Alternatively or additionally,
stent component 200 may have an indentation (e.g., annular groove)
or other fixation element 202, for example, for fixing the stent in
place at the implantation site. For example, when stent component
200 is part of double-stent-valve 400 (FIG. 4), fixation element
202 may matably attach to a complimentary fixation element 302
(e.g., inward annular projection, FIG. 3A) of stent component 300.
When stent component 200 is part of a single-stent valve (FIG. 2B),
fixation element 202 may affix to at least a portion of the failed
valve. Additional embodiments of stent components that may include
fixation elements are described in connection with FIGS. 6A and
8A-16.
[0068] In some embodiments of the present invention, stent
component 200, like valve component 100, may be capable of at least
two configurations: a first, collapsed configuration (e.g., during
delivery) and a second, expanded configuration (e.g., after
installation). FIG. 2A shows stent component 200 in an illustrative
expanded configuration. FIG. 2C shows stent component 200 in an
illustrative collapsed configuration, with the collapsed valve
component 100 housed therein, for example, for delivery of both
components to the implantation site at the same time. In some
embodiments, stent component 200 may be made from wire or may be
laser cut from a tube, sheath, or the like. Stent component 200 may
include a shape-memory alloy material such as, for example,
nitinol. The shape-memory alloy may allow for compression of stent
component 200 (and/or valve component 100) into the first
configuration for, for example, delivery through a small opening in
the patient's body and expansion of stent component 200 to the
second configuration during installation. Components 100 and/or 200
may be held in the collapsed configuration, for example, with a
sheath or wrap. The sheath/wrapping may be removed in order to
allow components 100 and/or 200 to reconfigure into the second
configuration.
[0069] Valve component 100 may be secured to stent component 200
via any suitable securing mechanism or combination of securing
mechanisms. For example, in one embodiment, valve component 100 may
be sutured with one or more stitches to stent component 200. In
another embodiment, valve component 100 may be secured to stent
component 200 by way of a friction fitting. For example, valve
component 100 may have a fully-expanded diameter that is slightly
larger than the expanded diameter of stent component 200 such that
components 100 and 200 fit securely together upon expansion of
component 100 within component 200. In yet another embodiment, a
hook-and-loop type (e.g., VELCRO.RTM.) fastening system may be used
to secure valve component 100 to stent component 200. For example,
stent component 200 may include microscopic hooks and valve
component 100 may include corresponding microscopic loops (or
vice-versa). This hook-and-loop fastening system may include a
micro-velour material, which has been used previously for surgical
applications to improve tissue in-growth. Such a hook-and-loop
fastening system may allow the position of valve component 100 to
be fine-tuned relative to the position of stent component 200, for
example, after components 100 and 200 have been implanted within a
patient's body. The hooks/loops may also facilitate blood clotting
and the formation of a seal at the interface between valve
component 100 and stent component 200. To avoid premature clot
formation (e.g., excessive clot formation before installation is
complete), anti-coagulation monitoring and/or treatment may be
provided to the patient. Reliable hook-and-loop connections may
still be achieved in the presence of premature clot formation,
although higher activation pressure (described below) may be
required. A preliminary evaluation shows that reliable
hook-and-loop connections can be formed in the presence of water,
jelly, liquid soap, and/or coagulating proteins. In some
embodiments, such a hook-and-loop fastening system may be used,
alternatively or additionally, to secure stent component 200 to
stent component 300 (e.g., with the microscopic hooks attached to
an exterior surface of stent component 200 and the corresponding
microscopic loops attached to an interior surface of stent
component 300, or vice versa).
[0070] Any suitable mechanism or combination of mechanisms (e.g.,
direct or indirect exertion of mechanical compression) can be used
to supply the activation pressure required to cause the micro-hooks
to attach to the micro-loops. For example, in some embodiments, one
or more balloons may be positioned adjacent to valve component 100
and/or stent component 200 (e.g., within valve component 100) and
inflated temporarily to bring the micro-hooks into contact with the
micro-loops. Such balloon(s) may placed within the valve component
100 and/or stent component 200 subsequent to delivery of the stent
and/or valve to the implantation site. Alternatively, in some
embodiments the balloon(s) can be mounted (e.g., removably mounted)
within the valve component 100 and/or stent component 200 prior to
delivery of the stent and/or valve to an implantation site (e.g.,
prior to loading the stent and/or valve into a delivery device).
The use of such balloon(s) is not limited to embodiments in which
the valve and stent are affixed to one another by way of
hooks/loops. Rather, such balloon(s) may be used whenever it is
necessary or desirable to use the balloon(s) to aid in the
expansion and/or engagement at the implantation site of the stent
and/or valve (e.g., when the valve is sutured to the stent). In
some embodiments, a self-expanding valve component 100 may be
provided that self-expands within stent component 200 in order to
cause the micro-hooks to contact the micro-loops.
[0071] FIG. 3A is a perspective view of stent component 300 in
accordance with an embodiment of the present invention. As
described above, stent component 300 may have a fixation element
302 (e.g., inward annular projection) that matably attaches to a
complimentary fixation element 202 of stent component 200 (FIG.
2A). FIG. 4 shows an embodiment of such matable attachment, in
which component 300 houses both components 100 and 200 to form
double-stent-valve 400. The geometry (e.g., length, width(s),
diameter(s), etc.) of stent component 300 may be particularly
suited, for example, for aortic valve replacement. In other
embodiments, other geometries and configurations of stent component
300 may be provided.
[0072] Stent component 300 may be secured in place at the
implantation site using any suitable securing mechanism or
combination of securing mechanisms. For example, in some
embodiments, fixation element 302 may form a recess (e.g., exterior
annular groove) for receiving at least a portion of the failed
valve. In some embodiments, stent component 300 may have a diameter
slightly larger than a diameter of the implantation site such that
delivery and expansion of stent component 300 at the implantation
site secures stent component 300 in place by way of a friction
fitting. In some embodiments, stent component 300 may include one
or more projections (e.g., spikes) or clasps for anchoring stent
component 300 to the failed valve and/or adjacent structure(s) at
the implantation site.
[0073] FIGS. 5A-7B illustrate embodiments of the present invention
for replacing a failed artificial (e.g., biological) valve (e.g.,
stent-valve) introduced to a patient's body during a prior surgery.
FIG. 5A is a perspective view of a failed biological valve 500
where leaflets 502 of the valve fail to close. FIG. 5B is a
perspective view of the failed biological valve 500 after
implantation of the stent-valve shown in FIG. 2B. As shown, failed
biological valve 500 (e.g., and/or its accompanying stent) secure
the new stent-valve in place at the implantation site. More
particularly, fixation element 202 of the stent-valve (FIGS. 2A and
2B), which may be an annular groove forming the narrowest portion
of the stent-valve, may receive the annulus of failed biological
valve 500 thereby securing the stent-valve in place. In other
embodiments of the present invention, at least a portion of failed
biological valve 500 may be removed from the patient's body (e.g.,
the failed valve itself), whereas other portion(s) of the failed
valve may be left behind at the implantation site (e.g., a
supporting stent). In still other embodiments, the failed
biological valve 500 including all of its associated component(s)
may be substantially entirely removed from the implantation site
prior to installation of the new stent-valve.
[0074] FIG. 6A is a perspective view of another example of a
stent-valve 600 in accordance with an embodiment of the present
invention. FIG. 6B is a perspective view showing a use of
stent-valve 600 to replace a failed artificial (e.g., biological)
valve. Stent-valve 600 includes one or more (e.g., three) locking
or retaining elements 602 along an outer surface of the stent
component. Each locking element 602 may include directionality such
that it collapses (e.g., becomes flush with an outer surface of the
stent component) upon engagement of the locking element with
another surface (e.g., the interior of a catheter). When a locking
element 602 protrudes from the outer surface of the stent
component, a first end 604 of the locking element may be adjacent
to the outer surface of the stent component, while a second end 606
of the locking component may be spaced apart from the outer surface
of the stent component. When multiple locking elements 602 are
provided, first ends 604 of all the locking elements may be
positioned at substantially the same vertical height/position along
the central axis of the stent component (e.g., albeit dispersed
evenly around the perimeter of the stent component), and second
ends 606 may be positioned at different vertical
height(s)/position(s) than first ends 604. First end 604 may be
flexible (e.g., allowing hinge-like movement in two dimensions)
such that movement of the second end relative to the outer surface
of the stent component does not impair the locking mechanism.
[0075] In some embodiments of the present invention, stent-valve
600 may be inserted into the interior of the failed valve in the
direction of arrow 608 in FIG. 6B. When first end 604 of each
locking element 602 encounters the interior diameter/annulus of the
failed valve, second end 606 of the locking element may collapse
toward the outer surface of the stent component. Upon second end
606 of the locking element reaching an open area of the failed
valve, the second end may jut outwardly, locking stent-valve 600 in
place. Thus, locking elements 602 may provide a mechanism for
securing the new stent-valve in place, as an alternative to or in
addition to fixation element 610 (e.g., annular groove) of the
stent component for affixing stent-valve 600 to (for example) the
annulus the failed valve.
[0076] FIGS. 7A and 7B show another embodiment of a stent component
700 with locking elements in accordance with the present invention.
FIG. 7A shows that such a stent component can be made from, for
example, a sheet of suitable material (e.g., nitinol). Referring to
FIG. 7B, stent component 700 includes one or more locking elements
702 that extend radially from an outer surface of the stent
component such that, for each locking element, first end 704 and
second end 706 of that locking element have substantially the same
vertical position/height along the central axis of the stent
component. In other embodiments, such locking elements may be
slightly angled, such that ends 704 and 706 of the same locking
element have different relative vertical positions/heights along
the central axis of the stent component. In some embodiments, a
stent component may be provided that includes multiple locking
elements, with each locking element having ends 704 and 706 with
different angular orientations. Different locking elements 702 may
have the same or different vertical positions/heights along the
central axis of the stent component.
[0077] FIGS. 8A-16 show additional examples of suitable stent
components for use in valve replacement in accordance with some
embodiments of the present invention. These stent components may be
used, for example, as part of single-stent-valves and
double-stent-valves. Each of these stent components includes one or
more attachment elements for removably attaching the stent
component (e.g., together with an integrated valve component) to a
delivery device (FIGS. 22-26). In some embodiments, these stent
components may also include a fixation element (e.g., similar to
fixation element 202 (FIG. 2A)) for fixing the stent component in
place at the implantation site.
[0078] FIG. 8A shows a perspective view of a stent component 800 in
a collapsed configuration, as well as an as-cut view of stent
component 800 that illustrates details regarding its structure.
FIG. 8B shows stent component 800 in an expanded configuration.
Stent component 800 includes first (e.g., proximal) section 802
that includes a fixation element (e.g., annular groove), second
section 804 that may follow the contour of a valve component to be
housed therein, and third (e.g., distal) section 806 that includes
one or more (e.g., three) attachment elements 808. In some
embodiments, stent component 800 may include (for example) a
lattice structure (e.g., formed from nitinol wire), for example,
with section 802 having a denser population of lattice cells than
section 804 and/or section 806. This may provide added support to
the fixation element in section 802 and therefore increase the
stability of device 800 at the implantation site. In some
embodiments, stent component 800 may include only closed lattice
cells in order to facilitate the recapture of stent component 800
by a delivery device when stent component 800 is in a
partially-expanded configuration (described below).
[0079] In some embodiments, each of attachment elements 808 may
include an opening (e.g., circular or ovular) for removably
attaching stent component 800 to a complimentary element (e.g.,
wire, strap or hook) of a delivery device. Attachment elements 808
may allow for partial expansion of the stent component (e.g.,
together with an integrated valve component and/or another stent
component) within a patient's body while causing the stent
component to remain attached to the delivery system. For example,
sections 802 and 804 (e.g., and part of section 806) of stent
component 800 may expand when stent component 800 is partially
released from a shaft during delivery, whereas no change may be
observed to the relative positions of attachment elements 808 still
constrained by the shaft (e.g., see FIG. 28 "partial release").
This may allow a surgeon to reposition and/or test the
functionality of the stent-valve (or double-stent-valve) within the
patient's body before finalizing deployment of the stent-valve at
the implantation site. Such testing of the valve functionality may
include peripheral pulse monitoring, whereby a pulse wave is
measurable if the valve is functioning properly. A more reliable
assessment of the stent valve function can be made with
transesophageal echocardiography (TEE), intravascular ultrasound
(IVUS) and/or intracardiac echocardiography (ICE). If the
stent-valve malfunctions during the test (e.g., if the valve does
not permit sufficient blood-flow), the stent-valve may be fully
recaptured by the delivery device and retrieved from the patient's
body. In other embodiments, stent component 800 may have a
different lattice structure, attachment elements 808 may be reduced
or enlarged in length and/or other dimension(s), and/or attachment
elements 808 may be included in other location(s) relative to stent
component 800 (e.g., within section 804).
[0080] FIG. 8C shows another embodiment of a stent component with
integrated attachment elements 814 that are configured such that
the fully expanded diameter in the region of the attachment
element(s) is smaller than the diameter of the region that houses
an associated valve. As shown in this example, the attachment
elements project partially inwardly toward the center axis of the
stent component. This may reduce the risk of injury to the
patient's body (e.g., perforation of the aorta) from the attachment
elements. Alternatively or additionally, this may make it easier to
affix the attachment elements to a complimentary structure of the
delivery device. For example, when the device is collapsed for
attachment to the delivery device, the reduced diameter within the
region of the attachment elements may cause the attachment elements
to engage the stent holder earlier.
[0081] FIG. 8D shows yet another embodiment of a stent component in
accordance with the present invention. In this embodiment, the
first (proximal) section of the stent includes 27 independent,
bendable elements 816, each of which may include connected and/or
disconnected cell(s) which can be open and/or closed. In this
embodiment, each bendable element includes a single, closed cell.
In other embodiments, other number(s) and/or configuration(s) of
the bendable elements may be provided. Bendable elements 816 allow
for accurate positioning/securing of the proximal stent section to
the geometry/topology of (for example) a calcified annulus/failed
biological valve. Each element 816 can bend/adapt independently to
the topology of the immediately adjacent portion of the calcified
annulus/failed biological valve. Bendable elements 816 collectively
form an annular groove in which the location of the bending
deformation (grooved portion) for each bendable element is
controlled by reducing or elongating the lengths of an attached
pair of stent struts (818, 820) which act as a joint. The length of
a single stent strut is shown by numeral 822. Primarily, the radial
force/resistance of each bendable element 816 is influenced by the
selection of angle 824 during stent manufacturing. Other design
parameters such as strut thickness/width also influence the radial
force. An advantage of this design is that the stent proximal
section can more adequately anchor the stent in place at the
implantation site independently of the stent mid section. Thus, the
stent mid section can be designed to accommodate (for example) the
aortic valve without any over sizing, therefore reducing the risk
of valve failure due to long term mechanical stress. The stent of
FIG. 8D also includes compensation element 826 (e.g., including a
triangular wave portion and two elongate arms) for accommodating
elongation mismatch (if any) within the stent during manufacturing
and/or crimping. Contrast FIG. 8D with the embodiment shown in FIG.
8C, in which the absence of dedicated pairs of struts prevents the
stent proximal section from having elements that bend independently
(e.g., during implantation).
[0082] FIG. 8E shows another embodiment of a stent component in
accordance with the present invention. In FIG. 8E, only about 1/3
of an as-cut view of the stent component is shown in order to more
clearly show its features. Similar to the locking/retaining
elements 602 shown in FIGS. 6A and 6B, the stent component shown in
FIG. 8E includes a plurality of independently bendable locking
elements 828 generally located within the region of the stent
component referenced as region 804 in FIG. 8B. Locking elements 828
form a crown that may engage, for example, a failed biological
valve or calcified native annulus from the outflow side. The stent
component in FIG. 8E also includes fixation element 830 (e.g.,
annular groove). In FIG. 8E, locking elements 828 are shown as
being positioned at substantially the same position/height along
the central axis of the stent component. In other embodiments,
different locking elements 828 may have the same or different
vertical positions/heights along the central axis of the stent
component similar to, for example, the stent shown in FIG. 7B.
Having different positions/heights for at least some of locking
elements 828 may facilitate engagement with, for example, native
valves of different sizes (e.g., a thin native valve which can be
engaged by locking elements separated by a small distance or a
thick native valve which can only be engaged by more distantly
spaced locking elements).
[0083] FIG. 8F shows another embodiment of a stent component in
accordance with the present invention. In FIG. 8F, only about 1/3
of an as-cut view of the stent component is shown in order to more
clearly show its features. FIG. 8F includes a Dacron pocket 832 for
housing a valve component, where Dacron pocket 832 is sutured along
the valve free edge 834. As shown, the valve component within
pocket 832 is housed more closely to attachment element(s) 836,
which are similar to attachment elements 808 in FIG. 8B, in the
embodiment of FIG. 8F than in the embodiment shown in FIG. 9C. A
middle inverted U-shaped strut 838 is slid into Dacron pocket 832.
The valve/pocket is sutured to an outer inverted U-shaped strut
840. Inner U-shaped strut 842 is positioned outside Dacron pocket
832 and serves as a skid during loading/releasing/recapturing of
the implant with a delivery device by reducing the friction forces
between Dacron pocket 832 and the outer sheath. Inner U-shaped
strut 842 may also be sutured to Dacron pocket 832. In some
embodiments, Dacron pocket 832 may be closed with further stitching
844. Although the bottom portion of the stent is not shown in FIG.
8F, in some embodiments it may include, for example, a fixation
element (e.g., annular groove) similar to fixation element 802 in
FIG. 8B.
[0084] FIGS. 9A-9C show another example of a stent component 900
with integrated attachment element(s) 902 in accordance with an
embodiment of the present invention. FIG. 9A shows a perspective
view of stent component 900 in a collapsed configuration, as well
as an as-cut view of stent component 900 that illustrates details
regarding its structure. FIG. 9B is a perspective view of stent
component 900 in an expanded configuration. FIG. 9C shows stent
component 900 (with an integrated valve component) positioned
beside a ruler to show its size (e.g., about 4 centimeters). As
shown, each of attachment elements 902 includes a circular or
ovular opening attached to stent component 900 by two supporting
elements 904 (e.g., wires). In turn, each pair of supporting
elements 904 attaches to a stem 906 (e.g., commissural post) within
the lattice structure. In contrast, each of the attachment elements
808 in FIG. 8B attaches to stent component 800 by a single
supporting element 810, and each supporting element 810 is attached
to a stem 812. All of the stent components shown in FIGS. 8A-16
include three stems, although it will be understood that other
suitable numbers of stems or no stems at all (e.g., FIG. 2A) may be
provided in accordance with some embodiments of the present
invention. Stent component 900 also includes a fixation element
908, which may be substantially similar to fixation element 202
(FIG. 2A). In the embodiment of FIG. 9C, the valve component is
sutured around the circumference of its annulus. Each of the three
leaflets of the valve component is also spot-sutured to the stent
to permit valve functionality. The locations of the sutures may be
selected in order to permit elongation of the stent during crimping
without damaging the valve or suture. For example, the inflow of
stent (e.g., within region 802 shown in FIG. 8B) may be covered on
its inner side with a cloth (e.g., mesh). The cloth and valve
component may be sutured to the stent (e.g., using a running and/or
interrupted technique) in the region adjacent to the annular groove
(e.g., along the border of stent sections 802 and 804 in FIG. 8B).
Some excess cloth on the inflow side may be folded over onto the
exterior side of the stent and sutured together with the valve
component in the vicinity of (e.g., further towards section 804)
the previous suturing location. The commissures of the valve
component may also be attached to the corresponding stent posts,
which may have previously been covered with cloth (e.g., Dacron).
Alternatively, pericardium or other suitable material can be used
to cover the stent component. In some embodiments, the valve
component may be a porcine valve component which may be harvested
as such or assembled from various donors in order to have an
optimal match between three cusps. Bovine and equine valves may
also be used that are made from pericardium. Other suitable sources
of valve components can also be used.
[0085] FIGS. 10A-10B show yet another example of a stent component
1000 with integrated attachment element(s) 1002 in accordance with
an embodiment of the present invention. FIG. 10A shows a
perspective view of stent component 1000 in a collapsed
configuration, as well as an as-cut view of stent component 1000
that illustrates details regarding its structure. FIG. 10B is a
perspective view of stent component 1000 in an expanded
configuration. As shown, at least one pair (e.g., all pairs) of
attachment elements 1002 are attached to one another with a bracing
element 1004. Each bracing element 1004 may attach on one end to a
first attachment element 1002 and on the other end to a second
attachment element 1002. In some embodiments, the bracing
element(s) 1004 may include a wire shaped like a triangular wave.
When all attachment elements 1002 include a bracing element 1004,
collectively the bracing elements 1004 may form a circle around the
perimeter of stent component 1000. Stent component 1000 may be
substantially the same as stent component 800 (FIG. 8B) in all
other respects.
[0086] FIGS. 11-16 show additional examples of stent components
with integrated attachment element(s) in accordance with some
embodiments of the present invention. Each of FIGS. 11-16 includes
a perspective view of a stent component in a collapsed
configuration, as well as an as-cut view of the stent component
that illustrates details regarding its structure. The following
description summarizes various features of the stent components
shown in FIGS. 11-16. Additional structural features of the
embodiments shown in FIGS. 8A-16 will be apparent to one of
ordinary skill in the art from the drawings.
[0087] FIG. 11 shows a stent component that includes shorter
supporting element(s) for attaching to a corresponding number of
ovular/circular attachment element(s) (i.e., shorter in comparison
to supporting elements 810 of FIG. 8B). The stem(s) in FIG. 11 for
attaching to the supporting elements may be substantially the same
as stems 906 in FIG. 9B.
[0088] FIG. 12 shows a stent component that includes two supporting
elements for attaching to each ovular/circular attachment element.
Each pair of supporting elements attaches to a stem such that
collectively the supporting elements and stem form a second
ovular/circular opening, for example, for added support and/or for
use as an additional or alternative attachment element. The stem(s)
in FIG. 12 may be substantially the same as stems 906 in FIG.
9B.
[0089] FIG. 13 shows a stent component that includes
non-circular/ovular attachment components such as, for example,
wires, hooks, straps, or a combination thereof for matably
attaching to a complimentary element of a delivery device (e.g., a
circular or ovular opening). The stent component in FIG. 13 also
includes an increased number of attachment elements (e.g., six)
when compared to the number of attachment elements (e.g., three) of
stent component 900 (FIGS. 9A and 9B). In FIG. 13, the attachment
elements attach directly to the stems of the stent component, two
attachment elements per stem. The stem(s) in FIG. 13 may be
substantially the same as stems 906 in FIG. 9B.
[0090] FIG. 14 shows a stent component that replaces the wire/hook
attachment elements in FIG. 13 with long, narrow openings (e.g.,
long and narrow in comparison to attachment elements 902 of FIG.
9A). The stem(s) in FIG. 14 may be substantially the same as stems
906 in FIG. 9B.
[0091] FIG. 15 shows a stent component with a modified lattice
structure, including a modified stem structure. The stent component
in FIG. 15 also includes circular/ovular attachment elements, where
each attachment element is attached to a stem by two supporting
elements. Each pair of supporting elements and corresponding stem
may form a second circular/ovular opening, in a manner similar to
the supporting element/stem configuration shown in FIG. 12.
[0092] FIG. 16 shows a stent component with attachment elements
modified relative to the attachment elements shown in FIG. 15. Each
attachment element in FIG. 16 includes a wire (e.g., a "U"-shaped
wire), with both ends of the wire attaching directly to the same
stem such that the attachment element/stem configuration forms a
substantially ovular/circular opening. The stem(s) in FIG. 16 may
be substantially the same as the stems shown in FIG. 15.
[0093] FIGS. 17/18, 19 and 20 show additional examples of
double-stent-valves in accordance with some embodiments of the
present invention. Single-stent valve 1700 of FIG. 17 includes
stent 1702 and valve component 1704. FIG. 18 shows a double-stent
valve that includes stent-valve 1700 and positioning stent 1802,
which may be attached together by way of (for example) an annular
groove and corresponding annular recess. Stent component 1802 may
be covered with, for example, pericardium in order to prevent
paravalvular leaking. The double-stent-valve of FIG. 18 may have a
generally cylindrical shape that is suitable for, for example,
pulmonary and/or aortic applications.
[0094] Now referring to FIGS. 19 and 20, FIG. 19 shows a
double-stent-valve with first stent 1902, second stent 1904, and
valve component 1906. FIG. 20 shows a double-stent-valve with first
stent 2002, second stent 2004, and valve component 2006. Again, the
positioning stents in FIGS. 19 and 20 may be covered (e.g., with
pericardium) in order to prevent paravalvular leaking. The stents
of FIGS. 19 and 20 may be suitable for, for example, pulmonary
valve replacement (e.g., in the presence of an aneurysm that
creates a deformation and where there is no suitable rim for
placement of a grooved stent-valve). More particularly, with
respect to pulmonary valve applications, many candidates for
pulmonary valve replacement have an aneurysm there or a funnel-type
configuration at the inflow or at the outflow. Thus, the first
stent 1902 or 2002 can adapt to this funnel-type pulmonary artery
configuration and provide the round orifice for securing the
stent-valve (1904, 1906) or (2004, 2006). In some embodiments, a
double-stent-valve similar to the double-stent-valve of FIG. 20 may
be provided that is suitable for mitral and/or tricuspid valve
applications, where the positioning stent has a reduced height and
an oval configuration that provides a round rim for attachment to a
groove of a stent-valve (alternatively, a hook-loop fastening
system can be used). Alternatively or additionally, the positioning
stent may have independently bendable elements that provide a
secure fit at the implantation site. Additional structural features
of the embodiments shown in FIGS. 17-20 and details regarding their
use for valve replacement will be apparent to one of ordinary skill
in the art from the drawings.
[0095] FIG. 21A shows another example of a stent-valve 2100 in
accordance with some embodiments of the present invention. The
embodiment shown in FIG. 21A may be suitable for, for example,
mitral valve replacement. Stent-valve 2100 may be assembled from a
stent component and a valve component outside the patient's body
prior to delivery of stent-valve 2100 to an implantation site.
Stent-valve 2100 may be a self-expanding stent-valve adapted for
replacement of the mitral valve. As shown, stent-valve 2100 may
have a shape similar to an opposed double crown. Stent-valve 2100
may include a porcine pulmonary valve 2102 sutured into a Dacron
conduit (prosthetic tube), with two self-expanding nitinol Z-stents
2104 and 2106 sutured on the external surface of the prosthesis in
such a way to create two self-expanding crowns. The self-expanding
stent-valve may be loaded for delivery into a Teflon sheath, or
other suitable delivery system. In this embodiment, Dacron is used
to cover the stent, although in other embodiments other materials
such as Teflon, silicon, pericardium, etc. may be used. In one
surgical approach, an incision of 1 centimeter may be made on the
left atrium, controlled by purse string sutures. The Teflon sheath
with loaded stent may be pushed along a guide wire (the atrium
having been punctured with a needle and the guide wire inserted)
until the middle of stent-valve reaches the mitral annulus. Then,
the sheath may be pulled back to deploy the ventricular side first,
followed by total removal of the sheath to expose the atrial side.
Additional details regarding stent-valve 2100 and a surgical
approach for delivering it to an implantation site are described in
Liang Ma et al., "Double-crowned valved stents for off-pump mitral
valve replacement", European Journal of Cardio-Thoracic Surgery
28:194-199, Jun. 13, 2005, which is incorporated by reference
herein in its entirety.
[0096] FIGS. 21B-E show views of a double-conical stent in
accordance with some embodiments of the present invention.
Referring to FIGS. 21B and 21C, the double-conical stent may
include a substantially cylindrical stent 2108 carrying a valve
2110 as well as two substantially conical stents (2112, 2114)
affixed/attached to stent 2108 (e.g., with VELCRO.RTM., suture(s),
friction fitting(s), other suitable affixing mechanism(s), or a
combination thereof). FIG. 21D shows a cross-section of the
double-conical stent shown in FIGS. 21B and 21C. In other
embodiments, at least one of stents 2112 and 2114 may have a
crown-shape with protruding spikes formed from open or closed cells
or Z-stents. The first and second additional stents (2112, 2114)
may collectively form a fixation element 2116 (FIG. 21C; e.g.,
annular groove) similar to fixation element 202 shown in FIG. 2A.
Fixation element 2116 may allow for fixation, for example, in an
orifice of a failed valve which is of similar size as the stent
2108 carrying valve component 2110 or to an anchoring stent with a
complimentary annular projection. In some embodiments, stents 2112
and 2114 (and optionally stent 2108) may be replaced with a single
stent in a double-conical configuration (e.g., the two cones
connected by a continuous region in the area of fixation element
2116). An advantage to using separate stent(s) for the
cones/fixation element is that the mechanical stresses of the
cones/fixation element (e.g., first and second stents 2112 and
2114) can be at least partially separated from stent 2108
containing the valve. In some embodiments, at least the additional
stent or portion thereof positioned closer to the tip of the
delivery system (e.g., stent 2112) may be recapturable by the
delivery system. To facilitate such recapturing, the additional
stent may be formed in a pyramid or wing cross-sectional
configuration 2118 (FIG. 21E). In some embodiments, the wing(s) or
spikes of stent 2112 (and/or 2114) may be formed at various
positions/heights along a central axis of stent 2108 similar to,
for example, the stent shown in FIG. 7B. Having different
positions/heights for at least some of the wings or spikes may
facilitate engagement with, for example, native valves of different
sizes. In some embodiments, the stents shown in FIGS. 21B-21E
(e.g., stent 2108) may include at least one attachment element for
removably attaching to a delivery device, similar to attachment
elements 808 shown in FIG. 8B.
[0097] FIGS. 22A-26C show examples of delivery systems for
delivering stent-valves (e.g., single-stent-valves or
double-stent-valves) to an implantation site in accordance with
some embodiments of the present invention. In some embodiments, the
present invention provides a minimally-invasive surgical approach
whereby the surgery is performed on a beating heart without the
need for an open-chest cavity and heart-lung bypass. The heart may
be penetrated, for example, trans-apically through a relatively
small opening in the patient's body. For example, to replace a
failed aortic valve, the patient's body may be penetrated through
an intercostal space (e.g., fifth intercostal space), which is a
region between two ribs. From this access point, the left ventricle
may be penetrated at the apex of the heart. In one approach, a
suitable stent-valve delivery system may initially penetrate the
body/heart (e.g., delivery system 2600 (FIGS. 26A-26C) which
includes an integrated introducer). In another approach, a separate
introducer sheath may be used. A guide wire (hollow needle,
catheter, stiff guide wire, etc.) may be inserted through the
introducer to guide delivery of, for example, stent component(s), a
valve component, and/or other devices (e.g., an occluder device).
In some embodiments, transluminal, transatrial, or transventricular
access approaches may be used for, for example, tricuspid and/or
mitral valve replacement. The right ventricle of the heart may also
be accessed for pulmonary valve replacement. This is in contrast to
other surgical approaches that deliver replacement valves via
open-chest cavities. Moreover, as described in greater detail below
in connection with FIGS. 22A-28C, delivery systems according to
some embodiments of the present invention release the proximal
portion of the stent-valve first, which may allow for testing of
the valve when the body is accessed, for example, trans-parietally.
Upon a successful test, the distal portion of the stent-valve may
be released. This contrasts with stent delivery systems that
initially release the distal portions of their associated
stents.
[0098] FIGS. 22A-22D show a delivery system 2200 that includes two
concentrically-arranged parts, a first assembly (including elements
2202-2210) and a second assembly (including elements 2216-2230).
More particularly, the first assembly may include tip 2202 at the
distal end of the delivery system (with a guide wire passing
through the length of the delivery system and out the tip), inner
shaft 2204, outer sheath 2206, metal shaft 2208, and push handle
2210. The second assembly may include outer shaft (distal) 2216,
tapered outer shaft connector 2218, outer shaft (proximal) 2220,
stent holder 2222, kink protector 2224, hold handle connector 2226,
hold handle cup 2228, and O-ring 2230. As shown, push handle 2210
is located at the proximal end of the delivery system. In FIGS. 22A
and 22B, outer shaft 2220 has been split along its length to allow
the components of delivery system 2200 to be shown in greater
detail. Valve 2212 and stent(s) 2214 form a third assembly that can
be, for example, loaded and crimped between the first and second
assemblies.
[0099] With respect to the first assembly, inner shaft 2204
functions as a lumen for a guide wire. Tip 2202 is bonded at its
distal end. As used herein, bonding refers to any suitable
securing/fastening mechanism such as, for example, adhesive bonding
using cyanoacrylate or UV-curing adhesives or thermal
bonding/welding using heat energy to melt the components to be
assembled. Outer sheath 2206 may be bonded to the proximal section
of tip 2202 and may constrain the stent-valve (2212, 2214). Outer
sheath 2206 may be perforated to allow device flushing via hold
handle 2210. The proximal part of the first assembly may be
reinforced with metal shaft 2208 and may end into the push handle
with a luer connector for guide wire lumen flushing.
[0100] With respect to the second assembly, stent holder 2222 may
be bonded distally on distal outer shaft 2216. FIG. 22D shows a
perspective view better illustrating the arrangement between the
stent-valve (2212, 2214) and stent holder 2222. Distal outer shaft
2216 may be bonded proximally to proximal outer shaft 2220 via
tapered connector 2218. Proximal outer shaft 2220 may be bonded via
kink protector 2224 to the hold handle assembly, which may include
hold handle connector 2226 and hold handle cup 2228. The hold
handle assembly may compress O-ring 2230 for sealing delivery
system 2200. A luer connector may allow for device flushing. The
flush mechanism may be used to remove trapped air from the delivery
system prior to its insertion into the body. Alternatively or
additionally, the flush mechanism may be used to cool down a stent
(e.g., nitinol stent) prior to its release and/or recapture by
flushing the stent with a cold saline solution. Cooling down the
stent may cause a reversible modification of its structure, thus
reducing its Young-modulus and therefore the stent radial force and
the forces necessary for its delivery and recapture.
[0101] Delivery system 2200 is said to be in an open position (FIG.
22C) when (for example) push handle 2210 contacts the hold handle
cup 2228. In the open position, the stent-valve (2212, 2214) may
detach from stent holder 2222 and fully expand at an implantation
site. Prior to delivery system 2200 reaching the open position, the
stent-valve may be crimped onto delivery system 2200 by means of a
crimping machine (for example) and held in place by stent holder
2222. Stent holder 2222 may affix to the attachment elements of the
stents shown in FIGS. 8A-16. The crimped stent-valve may be
maintained in a collapsed configuration by pulling back the first
assembly thus covering the attachment components/stent holder 2222
with outer sheath 2206. Once the outer sheath 2206 is removed such
that it no longer constrains the attachment components, the
stent-valve may automatically detach from stent holder 2222 due to
the self-expanding property of the stent-valve. Delivery system
2200 is said to be in a closed position (FIGS. 22A and 22B) when
outer sheath 2206 fully encompasses the stent-valve (2212, 2214)
such that no expansion of the stent-valve occurs.
[0102] Delivery system 2200 is said to be in a partially open
position when (for example) push handle 2210 is partially pushed
towards hold handle cup 2228. In this partially open position, the
stent-valve (2212, 2214) is deployed proximally and still attached
distally to stent holder 2222 via the attachment elements. This
allows for an accurate implantation/positioning of the stent-valve.
For example, the stent-valve may be partially released proximal to
the intended implantation site and slightly pushed distally until
resistance is felt. Final release of the stent-valve (2212, 2214)
may occur by completely pushing the push handle towards hold handle
cup 2228 so that delivery system 2200 reaches the open position.
Such a partially-open position is illustrated in FIG. 28B. In some
embodiments, an imaging mechanism may be used to determine whether
the stent-valve is positioned correctly at the implantation site.
For example, roadmapping under fluoroscopy can be realized with
angiography, intra-vascular ultrasound (IVUS), intra-cardiac
echocardiography (ICE), trans-esophageal echocardiography (TEE) or
other mechanism(s) or combination thereof, which imaging mechanism
may be at least partially integral to or separate from the delivery
system.
[0103] Upon implantation of the stent-valve (2212, 2214), delivery
system 2200 may revert to the closed position prior to retrieval
from the patient's body, for example, by holding the first assembly
and pushing the second assembly distally towards tip 2202/outer
sheath 2206. In other embodiments, the handle for releasing the
stent-valve may comprise a screw mechanism for transferring a
rotational movement of the handle into a translational movement of
the outer sheath. This type of release system may allow for
stepwise, more accurate stent release and recapturing as well as a
reduction of the release force felt by the surgeon.
[0104] FIGS. 23A-23D show another example of a delivery system 2300
in accordance with an embodiment of the present invention. Delivery
system 2300 may be substantially similar to delivery system 2200
(FIG. 22) (e.g., closed position, FIGS. 23A and 23B; opened
position, FIG. 23C), except delivery system 2300 may additionally
include one or more folded balloons 2302 (e.g., proximal to the
stent-valve). Unless otherwise indicated, like features in FIGS.
23A-23D correspond to the same reference numerals in FIGS. 22A-22D,
although the reference numerals have not been reproduced in FIGS.
23A-23D to avoid overcomplicating the drawings. The same applies to
the stent delivery systems shown in FIGS. 24A-D, FIGS. 25A-C, and
FIGS. 26A-C. Balloon 2302 may be inflated/deflated via an
additional lumen in proximal outer shaft 2304, for example, to
anchor the stent-valve (e.g., a non-self-expanding stent-valve) in
place at an implantation site. FIG. 23D shows a cross section "A-A"
of the lumen structure shown in FIG. 23C. The lumen structure
includes 5-lumen tubing 2306 and inner shaft 2308. In other
embodiments, other structures for lumen tubing 2306 may be used
(e.g., bitumen tubing where the second lumen is used for balloon
inflation and deflation). Delivery system 2300 may also include
access mechanism 2310 for balloon inflation/deflation, which may
allow connection of a syringe or inflation device to
inflate/deflate a balloon. Alternatively or additionally, tubing
with an attached stop-cock may be connected to access mechanism
2310.
[0105] FIGS. 24A-24D show another example of a delivery system 2400
in accordance with an embodiment of the present invention. In
delivery system 2400, proximal outer shaft 2402 may have an
increased diameter in comparison to the diameter of proximal outer
shaft 2220 (FIG. 22). The increased diameter may reduce bleeding
when the delivery system is used without an introducer.
Alternatively, when an introducer is used, the increased diameter
may match the internal diameter of the introducer which, in turn,
may depend on the outer diameter of the outer sheath. Having no gap
between the introducer and delivery system may reduce the risk of a
potential retrieval issue of the delivery system through the
introducer due to entrapped blood. Accordingly, delivery system
2400 may include a floating tube 2404 that fills the gap between
the inner and outer assemblies, thus reducing the risk of the inner
assembly kinking under compression which would result in higher
friction forces within the delivery system during stent
recapturing. Delivery system 2400 may be substantially similar to
delivery system 2200 in all other respects (e.g., closed position,
FIGS. 24A and 24B; opened position, FIG. 24C).
[0106] FIGS. 25A-C show another example of a delivery system 2500
in accordance with an embodiment of the present invention. Delivery
system 2500 may include one or more balloons 2536 distal to the
stent-valve. Having the balloon(s) distal to the stent-valve avoids
having to introduce the delivery system deeper into the body (e.g.,
into the ascending aorta) in order to perform dilation, thereby
reducing risk of injury to the body and improving device handling
(e.g., no bending of rigid device over the aortic arch). Balloon(s)
2536 can be used for, for example, valvuloplasty prior to
stent-valve implantation and/or post-dilation of the implanted
stent-valve to improve the anchoring of the stent. FIGS. 25B and
25C show the balloon(s) 2536 in closed and open positions,
respectively.
[0107] The first assembly of delivery system 2500 may include tip
2502, inner balloon shaft 2504, outer sheath 2506, and floating
tube 2508. The second assembly may include inner shaft (distal)
2510, stent holder transition 2512, stent holder 2514, sleeve 2516,
tapered transition shaft connector 2518, and outer shaft (proximal)
2520. The handle assembly may include hold handle connector 2522,
hold handle cup 2524, O-ring 2526, metal shaft 2528, and push
handle 2530. The balloon assembly may include outer shaft 2532,
inner shaft 2534, balloon 2536, and Y connector 2538.
[0108] FIGS. 26A-C show another example of a delivery system 2600
in accordance with an embodiment of the present invention. Delivery
system 2600 may include an integrated introducer 2602, which may be
an additional assembly that houses the second assembly. The outer
sheath of the delivery system is shown as 2604. Introducer 2602 may
include a connecting line 2606, a stopcock 2608 and a housing 2610
for the sealing membrane 2612. Stopcock 2608 may serve as an access
point for, for example, a syringe containing fluid (e.g., saline).
Connecting line 2606 may serve to transport the fluid from the
syringe to the inner lumen of the introducer, and sealing membrane
2612 may seal the introducer from the outside environment. Upon
stent-valve implantation, the components of delivery system 2600
(e.g., first assembly and second assembly) other than introducer
2602 may be retrieved through the introducer. Then, another medical
device such as, for example, a closure device may be introduced
through introducer 2602. Examples of closure devices are described
below in connection with FIGS. 29A-33B. As another example,
intravascular ultrasound (IVUS) equipment (e.g., mini-probe) may be
introduced through introducer 2602. Delivery system 2600 may be
substantially similar to delivery system 2200 in all other
respects.
[0109] FIG. 27 is a flowchart 2700 of illustrative stages involved
in replacing a failed (e.g., native or artificial) valve in
accordance with some embodiments of the present invention. FIGS.
28A-28C illustrate (without limitation) various stages referenced
in the flowchart of FIG. 27. At stage 2702, a stent-valve (e.g.,
single-stent-valve or double-stent-valve) may be removably attached
to a delivery system. For example, one or more attachment elements
of a stent component (e.g., attachment elements 808, FIG. 8B) may
be affixed to a stent holder of the delivery device (e.g., stent
holder 2222, FIG. 22). A collapsing element (e.g., outer sheath
2206, FIG. 22) may be placed over the attachment elements/stent
holder to maintain the stent-valve in a collapsed configuration and
attached to the delivery system.
[0110] At stage 2704, the stent-valve may be delivered to an
implantation site in a collapsed configuration. For example, FIG.
28A ("introduction" and "positioning") shows that stent-valve 2802,
while still attached to the delivery system via stent holder 2804
and fully contained within outer sheath 2806, may be introduced to
a patient's body along guide wire 2808 so that tip 2810 of the
delivery system passes through failed valve 2812. The delivery
system may be manipulated forwards and/or backwards, for example,
until the stent-valve is believed to be positioned correctly.
[0111] At stage 2706, the stent-valve may be partially expanded,
for example, to determine (stage 2708) whether the stent-valve is
in fact positioned correctly and/or to test (stage 2710) whether
the stent-valve is functioning properly. For example, FIG. 28A
("partial release") shows that outer sheath 2806 may be partially
removed from proximal section 2814 of the stent-valve, while
attachment elements 2816 of the stent-valve are still constrained
by outer sheath 2806 onto stent holder 2804.
[0112] At stage 2712, when the stent-valve is positioned correctly
at the implantation site and/or the stent-valve is functioning
properly, the stent-valve may be detached from the delivery system
in order to cause the stent-valve to expand to its fully-expanded
configuration. For example, FIG. 28C ("final release") shows that,
upon removal of attachment elements 2816 and stent holder 2804 from
within outer sheath 2806, attachment elements 2816 of stent-valve
2802 may detach from stent holder 2804 automatically (or in
response to balloon inflation in other embodiments) thereby causing
the stent-valve to expand to its fully-expanded configuration. The
second assembly of the delivery device may then be reunited with
the first assembly/outer sheath and removed from the patient's
body. For example, FIG. 28C ("delivery device retrieval") shows
that the second assembly 2818 may be passed through replacement
stent-valve 2802 towards the distal end of the stent-valve. Then,
the reunited second assembly 2818 and first assembly/outer sheath
2806 may be passed through stent-valve 2802 again in the proximal
direction before exiting the patient's body.
[0113] When the stent-valve is not positioned correctly (stage
2708), at stage 2714 the stent-valve may be reverted to the
collapsed configuration and repositioned within the patient's body.
An illustration of this scenario is illustrated in FIG. 28B ("stent
recapturing/repositioning"), in which outer sheath 2806 is slid in
the proximal direction over proximal section 2814 of the
stent-valve in order to recapture the stent-valve. The stent-valve
is then repositioned and released such that fixation element 2820
of the stent-valve receives an annulus 2822 of the failed valve.
Similarly, when the stent-valve malfunctions in response to a test
(stage 2710), at stage 2716 the stent-valve may be reverted to the
collapsed configuration and removed from the patient's body.
[0114] FIGS. 29A-33B show illustrative embodiments of guide wire
compatible closure (occluder) devices for sealing access orifices
and associated surgical instruments in accordance with some
embodiments of the present invention. Such an occluder may repair,
for example, a cardiac access orifice (e.g., ventricular orifice)
used for valve replacement. The occluder may be introduced to a
patient's body after a replacement valve has been implanted (or
removed due to malfunction or complication during installation).
Embodiments of the present invention address shortcomings with
conventional closure devices, such as the looseness of their fit.
Conventional closure devices also lack a central lumen, which
renders them incompatible with guide wire delivery systems.
[0115] FIGS. 29A and 29B are side and perspective views of an
occluder 2900 in accordance with some embodiments of the present
invention. Occluder 2900 may include stainless steel wire, nitinol,
textile fibers, fills, biocompatible materials, and/or other
suitable materials which allow the device to perform as intended.
In some embodiments, at least a portion of occluder 2900 may be
fitted/filled with a flexible but tight material such as, for
example, a membrane or foam. Occluder 2900 may or may not include a
skeleton (e.g., lattice structure with a filling material) and/or
sealing membranes. Such a skeleton may comprise nitinol, stainless
steel, magnesium, nylon, polyester, polypropylene, polydioxanon,
other suitable material(s), or a combination thereof. The filling
material may include, for example, polyester, polyurethane,
gelatin, other suitable material(s), or a combination thereof. When
occluder 2900 includes a sealing mechanism, such a mechanism may be
flexible such that it does not interfere with the expanding or
collapsing of occluder 2900 (described below) according to some
embodiments of the present invention.
[0116] Top portion 2902 of occluder 2900 may be positioned on the
luminal side of an access orifice, while bottom portion 2904 may be
positioned outside the access orifice. Guide wire compatibility may
be achieved through a central channel within occluder 2900. The
central channel may include at its bottom end, for example, a
hollow screw device 2906 for attaching occluder 2900 to a catheter
during delivery and detaching the occluder from the catheter upon
installation within the access orifice. In other embodiments,
occluder 2900 may be attached/detached to a catheter by a thin wall
that can be twisted off, by a connection mechanism in the shape of
a hook, or by a mechanism that detaches via galvanic corrosion or
the like.
[0117] Occluder 2900 may include a channel sealing mechanism 2908
such as, for example, a self-sealing membrane and/or foam. In some
embodiments, channel sealing mechanism 2908 may include a valve
(e.g., one or more plastic leaflets). Channel sealing mechanism
2908 may prevent blood-flow through the occluder from top/luminal
portion 2902 to bottom portion 2904 after the occluder is installed
within the access orifice. During delivery, the positioning of a
guide wire through channel sealing mechanism 2908 (and the central
channel) may or may not substantially or entirely prevent
blood-flow through channel sealing mechanism 2908. In some
embodiments, mechanism 2908 may rely, at least in part, on blood
clotting in order to form a seal. In some embodiments, mechanism
2908 (including a membrane, an iris mechanism, or collapsible
walls) may form the seal (with or without assistance from blood
clotting).
[0118] In some embodiments, top/luminal portion 2902 of occluder
2900 may be made from different material(s) (or the same
material(s) but having different characteristics) than the
material(s) used for bottom/outer portion 2904. For example,
bottom/outer portion 2904 made be made from a coarser or more
porous material than top/luminal portion 2902 to facilitate the
formation of scar tissue on the outer portion. Bioabsorbable
material(s) may also be used for portion 2902 and/or 2904 of
occluder 2900 (e.g., magnesium and/or polydioxanone for a skeleton
portion and/or polydioxanone, polyhydroxybutyrate, and/or gelatin
as a filler).
[0119] FIG. 30 shows a perspective view of a guide wire 3000 for
guiding the delivery of occluder 2900 to the access orifice. Guide
wire 3000 may be the same guide wire used, for example, for a valve
replacement surgery involving one of the delivery systems shown in
FIGS. 22A-26C. FIG. 31 shows a perspective view of a threaded
catheter 3100 for attaching to occluder 2900 during delivery and
detaching from occluder 2900 once installation of the occluder is
complete. As shown in FIGS. 32A and 32B, screw device 2906 of
occluder 2900 may attach to threaded catheter 3100, and occluder
2900 may be loaded into second catheter 3202. For example, second
catheter 3202 may be part of the delivery system (e.g., FIG. 26A-C)
used for delivery of a replacement valve. Guide wire 3000 may
extend through both the central channel of occluder 2900 and second
catheter 3200. Guide wire 3000 may also be removable and
reinsertable. FIG. 32B shows that the occluder can be partially
unloaded by moving catheter 3100 relative to catheter 3202.
Advantageously, if occluder 2900 is not positioned correctly upon
partial release, it can be reloaded into catheter 3202 and
relocated to the proper location within the access orifice without
excessive manipulation of occluder 2900 and/or the associated
delivery instruments.
[0120] FIGS. 33A and 33B illustrate side and perspective views of
occluder 2900 in an expanded configuration within an access orifice
in accordance with an embodiment of the present invention.
Preferably, luminal/top portion 2902 and outer/bottom portion 2904
of occluder 2900 cover the access orifice completely. The central
channel is also preferably sealed by, for example, a self-sealing
membrane and/or sealing foam 2908.
[0121] 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 inventors that
various substitutions, alterations, and modifications may be made
without departing from the spirit and scope of the 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
inventors reserve the right to pursue such inventions in later
claims.
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