U.S. patent application number 14/481139 was filed with the patent office on 2014-12-25 for circulatory valve, system and method.
This patent application is currently assigned to Boston Scientific Scimed, Inc.. The applicant listed for this patent is Boston Scientific Scimed, Inc.. Invention is credited to William J. Drasler, Jason P. Hill, Mark L. Jenson, Joseph M. Thielen.
Application Number | 20140379068 14/481139 |
Document ID | / |
Family ID | 39800532 |
Filed Date | 2014-12-25 |
United States Patent
Application |
20140379068 |
Kind Code |
A1 |
Thielen; Joseph M. ; et
al. |
December 25, 2014 |
Circulatory Valve, System and Method
Abstract
Apparatuses, systems, and methods for use in a vascular system.
The apparatus include a circulatory valve having a valve frame in
which frame members define frame cells. Frame cells include joints
in opposing relationship, where the joints transition from a first
stable equilibrium state through an unstable equilibrium state to a
second stable equilibrium state as the joints are drawn towards
each other.
Inventors: |
Thielen; Joseph M.;
(Buffalo, MN) ; Hill; Jason P.; (Brooklyn Park,
MN) ; Jenson; Mark L.; (Greenfield, MN) ;
Drasler; William J.; (Minnetonka, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Boston Scientific Scimed, Inc. |
Maple Grove |
MN |
US |
|
|
Assignee: |
Boston Scientific Scimed,
Inc.
Maple Grove
MN
|
Family ID: |
39800532 |
Appl. No.: |
14/481139 |
Filed: |
September 9, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11881220 |
Jul 26, 2007 |
8828079 |
|
|
14481139 |
|
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Current U.S.
Class: |
623/1.11 ;
623/1.26 |
Current CPC
Class: |
A61F 2002/9665 20130101;
A61F 2/82 20130101; A61F 2/2427 20130101; A61F 2/2433 20130101;
A61F 2/95 20130101; A61F 2210/0076 20130101; A61F 2230/0013
20130101; A61F 2/2418 20130101; A61F 2/2439 20130101; A61F 2/2436
20130101; A61F 2/2475 20130101 |
Class at
Publication: |
623/1.11 ;
623/1.26 |
International
Class: |
A61F 2/24 20060101
A61F002/24; A61F 2/82 20060101 A61F002/82; A61F 2/95 20060101
A61F002/95 |
Claims
1. A method for staged deployment of a circulatory valve,
comprising: radially expanding a valve frame of the circulatory
valve from an undeployed state to a first stable equilibrium state;
and transitioning joints of the valve frame from the first stable
equilibrium state through an unstable equilibrium state to a second
stable equilibrium state to deploy the circulatory valve.
2. The method of claim 1, where radially expanding the valve frame
from the undeployed state includes releasing the circulatory valve
from the undeployed state.
3. The method of claim 1, where transitioning the joints from the
first stable equilibrium state through the unstable equilibrium
state to the second stable equilibrium state includes drawing the
joints in each of a frame cell toward each other.
4. The method of claim 3, where stopping the movement of the joints
in each frame cell before passing the unstable equilibrium state
causes the joints to return toward the first stable equilibrium
state.
5. The method of claim 1, where transitioning joints of the valve
frame include pulling the joints through the unstable equilibrium
state to the second stable equilibrium state.
6. The method of claim 1, including locking the valve frame in the
second stable equilibrium state with a lock mechanism.
7. The method of claim 1, including flexing a compliant segment of
the valve frame as the joints of the valve frame transition from
the first stable equilibrium state through the unstable equilibrium
state to the second stable equilibrium state to help hold the
circulatory valve in the deployed state.
8. The method of claim 1, where transitioning the joints includes
elastically deforming the joints from the first stable equilibrium
state through the unstable equilibrium state to the second stable
equilibrium state to deploy the circulatory valve.
9. The method of claim 1, where radially expanding the valve frame
includes expanding the valve frame to eighty (80) to ninety-five
(95) percent of the second stable equilibrium state for the first
stable equilibrium state.
10. A system, comprising: an elongate delivery catheter; a
retractable sheath positioned around at least a portion of the
elongate delivery catheter, where the retractable sheath moves
longitudinally relative the elongate delivery catheter; a
circulatory valve positioned between the elongate delivery catheter
and the retractable sheath, where the circulatory valve includes a
valve frame having frame members defining frame cells with joints
in opposing relationship, and a valve leaflet coupled to the valve
frame; and deployment threads that extend longitudinally between
the elongate delivery catheter and the retractable sheath to the
joints of the frame cells, where force applied through the
deployment threads transitions the joints from a first stable
equilibrium state through an unstable equilibrium state to a second
stable equilibrium state.
11. The system of claim 10, where the retractable sheath moves
longitudinally relative the elongate delivery catheter to allow the
circulatory valve to move from an undeployed state to the first
stable equilibrium state.
12. The system of claim 11, where the first stable equilibrium
state is eighty (80) to ninety-five (95) percent of the second
stable equilibrium state.
13. The system of claim 10, including a push tube that extends
longitudinally between the elongate delivery catheter and the
retractable sheath to abut at least one of the joints, and where
the deployment threads extend through the push tube to the joints
of the frame cell to allow force to be applied to the joints
between the deployment threads and the push tube.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of and claims priority to
application of Ser. No. 11/881,220, filed Jul. 26, 2007, the
contents of which are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to apparatuses,
systems, and methods for use in the vascular system; and more
particularly to apparatuses, systems, and methods for native valve
replacement and/or augmentation.
BACKGROUND
[0003] Valves of the vascular system can become damaged and/or
diseased for a variety of reasons. For example, damaged and/or
diseased cardiac valves are grouped according to which valve or
valves are involved, and the amount of blood flow that is disrupted
by the damaged and/or diseased valve. The most common cardiac valve
diseases occur in the mitral and aortic valves. Diseases of the
tricuspid and pulmonary valves are fairly rare.
[0004] The aortic valve regulates the blood flow from the heart's
left ventricle into the aorta. The aorta is the main artery that
supplies oxygenated blood to the body. As a result, diseases of the
aortic valve can have a significant impact on an individual's
health. Examples of such diseases include aortic regurgitation and
aortic stenosis.
[0005] Aortic regurgitation is also called aortic insufficiency or
aortic incompetence. It is a condition in which blood flows
backward from a widened or weakened aortic valve into the left
ventricle of the heart. In its most serious form, aortic
regurgitation is caused by an infection that leaves holes in the
valve leaflets. Symptoms of aortic regurgitation may not appear for
years. When symptoms do appear, it is because the left ventricle
must work harder relative to an uncompromised aortic valve to make
up for the backflow of blood. The ventricle eventually gets larger
and fluid backs up.
[0006] Aortic stenosis is a narrowing or blockage of the aortic
valve. Aortic stenosis occurs when the valve leaflets of the aorta
become coated with deposits. The deposits change the shape of the
leaflets and reduce blood flow through the valve. Again, the left
ventricle has to work harder relative to an uncompromised aortic
valve to make up for the reduced blood flow. Over time, the extra
work can weaken the heart muscle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The features of the drawing are not to scale.
[0008] FIG. 1 illustrates an example of a cardiac valve according
to the present disclosure.
[0009] FIG. 2 illustrates an example of a frame cell according to
the present disclosure.
[0010] FIG. 3 illustrates an example of a joint and compliant
section of a frame cell according to the present disclosure.
[0011] FIG. 4A illustrates an example of a cardiac valve in an
undeployed state according to the present disclosure.
[0012] FIG. 4B illustrates an example of the cardiac valve of FIG.
4A in a deployed state according to the present disclosure.
[0013] FIG. 5 illustrates an example of a cardiac valve according
to the present disclosure.
[0014] FIG. 6 illustrates an example of a frame cell and a locking
mechanism according to the present disclosure.
[0015] FIG. 7 illustrates an example of a frame cell and a
deployment mechanism according to the present disclosure.
[0016] FIGS. 8A and 8B illustrate a cross-sectional view of an
embodiment of a system that includes a cardiac valve according to
the present disclosure.
[0017] FIG. 8C illustrates a balloon catheter used with an
embodiment of the system that includes a cardiac valve according to
the present disclosure.
DETAILED DESCRIPTION
[0018] Embodiments of the present invention are directed to
apparatuses, systems, and methods for native valve replacement
and/or augmentation. For example, the apparatus can include a
circulatory valve that can be used to replace an incompetent native
valve (e.g., an aortic valve, a mitral valve, a tricuspid valve, a
pulmonary valve, and/or a venous valve) in a body lumen.
Embodiments of the valve include a valve frame having frame members
defining frame cells with joints that transition from a first
stable equilibrium state through an unstable equilibrium state to a
second stable equilibrium state as the joints are drawn towards
each other. In one example, embodiments of the present disclosure
may help to augment or replace the function of a native valve of
individuals having heart and/or venous valve disease.
[0019] The figures herein follow a numbering convention in which
the first digit or digits correspond to the drawing figure number
and the remaining digits identify an element or component in the
drawing. Similar elements or components between different figures
may be identified by the use of similar digits. For example, 110
may reference element "10" in FIG. 1, and a similar element may be
referenced as 210 in FIG. 2. As will be appreciated, elements shown
in the various embodiments herein can be added, exchanged, and/or
eliminated so as to provide any number of additional embodiments of
a valve and/or a system. In addition, as will be appreciated the
proportion and the relative scale of the elements provided in the
figures are intended to illustrate the embodiments of the present
invention, and should not be taken in a limiting sense.
[0020] Various embodiments of the present disclosure are
illustrated in the figures.
[0021] Generally, the circulatory valve can be implanted within the
fluid passageway of a body lumen, such as for replacement or
augmentation of a native cardiac valve structure within the body
lumen (e.g., an aortic valve), to regulate the flow of a bodily
fluid through the body lumen in a single direction.
[0022] The embodiments of the circulatory valve of the present
disclosure include a valve frame that self-expands to a first
stable equilibrium state. The first stable equilibrium state of the
valve frame is a partially deployed state relative the deployed
state of the circulatory valve. In this partially deployed state,
the position of the circulatory valve relative the desired implant
location can be adjusted to correct any foreshortening and/or stent
jump that can occur in self-expanding stents as they expand from
the small compressed undeployed state. In addition, having the
circulatory valve in the partially deployed state prior to
completing the deployment allows for adjustments due to movement
caused by the flow output from the ventricle pushing on the
deployment system, which can be the case when implanting an aortic
valve.
[0023] As used herein, a partially deployed state of the valve
frame lies between an undeployed state (i.e., the state of the
valve frame at the time the valve is outside the body) and a
deployed state (i.e., the state of the valve frame at the time the
valve is to be left in the body). Structures on the circulatory
valve can then be transitioned from the first stable equilibrium
state through an unstable equilibrium state to a second stable
equilibrium state to deploy the circulatory valve.
[0024] In the various embodiments, holding the valve frame in the
partially deployed state allows the circulatory valve to be better
positioned in a desired location prior to its final deployment.
This staged deployment of the circulatory valve of the present
disclosure is in contrast to circulatory valves that are deployed
without the advantage of temporarily pausing at an intermediate
deployment stage (i.e., the partial deployment state) to allow for
adjustments in the placement of circulatory valve prior to full
deployment.
[0025] FIG. 1 provides an embodiment of a circulatory valve 100 of
the present disclosure. The circulatory valve 100 includes a valve
frame 102 and a valve leaflet 104 coupled to the valve frame 102.
The valve frame 102 also includes frame members 106 that define a
frame cell 108. The frame cell 108 can include joints 110 that
transition from a first stable equilibrium state through an
unstable equilibrium state to a second stable equilibrium state. In
one embodiment, this transition can occur as one or more of the
joints 110 are drawn towards each other, as will be discussed
herein.
[0026] The valve frame 102 has an elongate tubular structure with a
proximal end 112 and a distal end 114. In one embodiment, the frame
cell 108 of the present disclosure can be positioned so as to
provide both the proximal and distal ends 112, 114 of the valve
frame 102. In other words, portions of the frame cell 108 define
the proximal and distal ends 112, 114 of the valve frame 102. In an
additional embodiment, the frame cell 108 of the present disclosure
can be located between proximal and distal ends 112, 114 of the
valve frame 102 (i.e., portions of the frame cell 108 does not
define the proximal end 112 and/or the distal end 114 of the frame
102). In an alternative embodiment, the frame cell 108 of the
present disclosure can be located at one of either the proximal end
112 or the distal end 114 of the valve frame 102. Different
combinations are also possible.
[0027] For the various embodiments, the joints 110 can be located
at a number of different positions on the frame member 106. For
example, the joints 110 can be located at the same relative
position along the frame member 106. So, when a frame cell 108
includes two joints 110, they can be set opposite each other in a
mirror image relationship. This aspect of the disclosure is
illustrated in FIG. 1, which shows the circulatory valve 100 in the
first stable equilibrium state. Alternatively, the joints 110 can
be at different relative locations along the frame member 106, as
will be discussed herein.
[0028] In an additional embodiment, the joints 110 can be located
on the frame member 106 such that as the joint 110 transitions from
the first stable equilibrium state to the second stable equilibrium
state the size (e.g., length) of the perimeter of the valve frame
102 increases. In other words, the joints 110 are located on the
frame member 106 in such a way as to cause the valve frame 102 to
radially increase in size as the joints 110 move toward the second
stable equilibrium state. In one embodiment, the valve frame 102
increases its perimeter size as the frame cell 108 change shape
during the joint 110 transition. As will be appreciated, some
change to the longitudinal dimension of the valve frame 102 may
occur as the perimeter dimension changes.
[0029] As discussed, FIG. 1 provides an illustration where the
joints 110 of the valve frame 102 are in the first stable
equilibrium state. In the various embodiments, this first stable
equilibrium state places the valve frame 102 in a partially
deployed state. As used herein, a partially deployed state of the
valve frame lies between an undeployed state (i.e., the state of
the valve frame at the time the valve is outside the body) and a
deployed state (i.e., the state of the valve frame at the time the
valve is to be left in the body). The valve frame 102 remains in
partially deployed state until the joints 110 are moved to the
second stable equilibrium state, as discussed herein. In one
embodiment, the valve frame 102 in the first stable equilibrium
state is eighty (80) to ninety-five (95) percent of the deployed
state. Other percentages of the deployed state are possible (e.g.,
ninety (90) percent of the deployed state).
[0030] In the various embodiments, the frame cell 108 can include
one or more of the joints 110. As illustrated in FIG. 1, the frame
cells 108 include two of the joints 110. In an additional
embodiment, each frame cell 108 of the valve frame 102 need not
have a joint 110. In other words, a frame cell 108 without a joint
110. So, in one embodiment a valve frame 102 could be configured in
such a way that not every frame cell 108 includes a joint 110.
[0031] Frame cells 108 not having a joint 110 could be integrated
into the valve frame 102 to provide structural characteristics to
the frame 102 that are advantageous to the operation of the valve
100. For example, the frame cell 108 without the joint 110 may be
more flexible in the radial direction to better accommodate
physiological changes at the implant site. Examples of such design
properties include, but are not limited to, providing an elastic
radial force where the frame members 106 can have serpentine bends
that provide for, at least in part, the elastic radial force. Other
shapes and configurations for the frame cell 108 (with or without
the joint 110) are also possible.
[0032] For the various embodiments, the valve frame 102 can be
self-expanding. Examples of self-expanding frames include those
formed from temperature-sensitive memory alloy which changes shape
at a designated temperature or temperature range. Alternatively,
the self-expanding frames can include those having a spring-bias.
Examples of suitable materials include, but are not limited to,
medical grade stainless steel (e.g., 316L), titanium, tantalum,
platinum alloys, niobium alloys, cobalt alloys, alginate, or
combinations thereof. Examples of shape-memory materials include
shape memory plastics, polymers, and thermoplastic materials which
are inert in the body. Shaped memory alloys having superelastic
properties generally made from ratios of nickel and titanium,
commonly known as Nitinol, are also possible materials. Other
materials are also possible.
[0033] For the various embodiments, the frame member 106 can have
similar and/or different cross-sectional geometries along its
length. The similarity and/or the differences in the
cross-sectional geometries can be based on one or more desired
functions to be elicited from each portion of the valve frame 102
and/or the frame cell 108. Examples of cross-sectional geometries
include rectangular, non-planar configuration, round (e.g.,
circular, oval, and/or elliptical), polygonal, arced, and tubular.
Other cross-sectional geometries are possible.
[0034] The circulatory valve 100 can further include one or more
radiopaque. markers (e.g., tabs, sleeves, welds). For example, one
or more portions of the valve frame 102 can be formed from a
radiopaque material. Radiopaque markers can be attached to and/or
coated onto one or more locations along the valve frame 102.
Examples of radiopaque material include, but are not limited to,
gold, tantalum, and platinum. The position of the one or more
radiopaque markers can be selected so as to provide information on
the position, location and orientation of the valve 100 during its
implantation.
[0035] The circulatory valve 100 further includes the leaflets 104
having surfaces defining a reversibly sealable opening for
unidirectional flow of a liquid through the valve 100. For example,
the leaflets 104 can be coupled to the valve frame 102 so as to
span and control fluid flow through the lumen of the valve 100. For
the present embodiment, the valve 100 includes two of the valve
leaflet 104 for a bi-leaflet configuration. As appreciated,
mono-leaflet, tri-leaflet and/or multi-leaflet configurations are
also possible. The each of the valve leaflet 104 are coupled to the
valve frame 102, where the leaflets 104 can repeatedly move between
an open state and a closed state for unidirectional flow of a
liquid through a lumen of the circulatory valve 100.
[0036] In one embodiment, the leaflets 104 can be derived from
autologous, allogeneic or xenograft material. As will be
appreciated, sources for xenograft material (e.g., cardiac valves)
include, but are not limited to, mammalian sources such as porcine,
equine, and sheep. Additional biologic materials from which to form
the valve leaflets 104 include, but are not limited to, explanted
veins, pericardium, facia lata, harvested cardiac valves, bladder,
vein wall, various collagen types, elastin, intestinal submucosa,
and decellularized basement membrane materials, such as small
intestine submucosa (SIS), amniotic tissue, or umbilical vein.
[0037] Alternatively, the leaflets 104 could be formed from a
synthetic material. Possible synthetic materials include, but are
not limited to, expanded polytetrafluoroethylene (ePTFE),
polytetrafluoroethylene (PTFE),
polystyrene-polyisobutylene-polystyrene (SIBS), polyurethane,
segmented poly(carbonate-urethane), polyester, polyethlylene (PE),
polyethylene terephthalate (PET), silk, urethane, Rayon, Silicone,
or the like. In an additional embodiment, the synthetic material
can also include metals, such as stainless steel (e.g., 316L) and
nitinol. These synthetic materials can be in a woven, a knit, a
cast or other known physical fluid-impermeable or permeable
configurations. In addition, plated metals (e.g., gold, platinum,
rhodium) can be embedded in the leaflet 104 material (e.g., a
sandwich configuration) to allow for visualization of the leaflets
104 post placement.
[0038] As will be appreciated, the valve 100 can be treated and/or
coated with any number of surface or material treatments. Examples
of such treatments include, but are not limited to, bioactive
agents, including those that modulate thrombosis, those that
encourage cellular in growth, through growth, and
endothelialization, those that resist infection, and those that
reduce calcification.
[0039] For the various embodiments, the frame cell 108 also
includes a compliant segment 116 that extend between a corner
portion 118 and the joint 110 of the frame cell 108. The compliant
segment 116 can elastically flex, or deflect, from the corner
portion 118 as the joint 110 transitions from the first stable
state through the unstable state to the second stable state. The
compliant segment 116 in its deflected state can then assist in
holding the joint 110 in the second stable equilibrium state.
[0040] In one embodiment, the combination of the joint 110 and the
compliant segment 116 provide for a bistable compliant mechanism.
The bistable compliant mechanism used in frame cell 108 includes
two stable equilibrium states within its range of motion. In the
present embodiments, these are the first stable equilibrium state
and the second stable equilibrium state, with an unstable
equilibrium state positioned there between. The bistable mechanism
used in the present disclosure does not require power input for the
joint 110 of the cell 108 to remain stable at each equilibrium
state. The states of stable equilibrium are essentially positions
of relative potential energy minimums to which the joints 110 and
the compliant segment 116 of the frame cells 108 return when the
unstable equilibrium state is not achieved.
[0041] FIG. 2 provides an illustration of joint 210 and compliant
segment 216 transitioning from the first stable equilibrium state
222 through the unstable equilibrium state 224 to the second stable
equilibrium state 226. In one embodiment, this transition occurs as
the joint 210 are drawn towards each other. Embodiments
illustrating how this force can be applied to the joint 210 and the
compliant segment 216 will be described herein.
[0042] In addition to illustrating the transition of joint 210 and
the compliant segment 216, FIG. 2 also provides a graph 230 that
illustrates the relative position of the equilibrium states 222 and
226 of the joint 210 and compliant segment 216 as a function of
potential energy 232. As illustrated in graph 230, the first and
second stable equilibrium states 222 and 226 of the joint 210 and
the compliant segment 216 are located at local potential energy
minimums (either equal or unequal) with the unstable equilibrium
state 224 positioned between the two states 222 and 226. The graph
230 also illustrates that due to the elastic nature of the joint
210 and compliant segment 216 changes to their shape away from the
first stable equilibrium state 222 will not result in transition to
the second stable equilibrium state 226 unless enough force is
supplied to overcome the unstable equilibrium state 224.
[0043] FIG. 2 also illustrates how the longitudinal length 228 of
the frame cell 208 is greater in the second stable equilibrium
state 226 as compared to the first stable equilibrium state 222.
This change in longitudinal length 228 of the frame cell 208 helps
to increase the peripheral length of the valve in which the frame
cell 208 is used, as discussed herein.
[0044] As will be appreciated, the configuration and design of the
joint 210 and the compliant segment 216 for the cell 208 can change
the relative values for the first and second stable equilibrium
states 222, 226. For example, such design aspects as a radius of
curvature and arc length, among others, for the corner portions 218
and/or the compliant segment 216 can affect relative values for the
first and second stable equilibrium states 222, 226. In addition,
the number, the position and the configuration of the joint 210 on
each frame cell 208 can also affect relative values for the first
and second stable equilibrium states 222, 226. Changes to the
cross-sectional shape and/or relative dimensions of the member 206
of the different components (e.g., the joint 210 and the compliant
segment 216) can also affect relative values for the first and
second stable equilibrium states 222, 226.
[0045] For the various embodiments, the joint of the present
disclosure can have a number of different configurations. For
example, the joint 210 illustrated in FIG. 2 has a looped
configuration, where the frame member 206 curves over on itself to
form a closed curve. In one embodiment, the frame member 206 can be
curved over on itself more than once.
[0046] In an alternative embodiment, the frame member forming the
joint can have a partially open configuration. FIG. 3 provides an
illustration of such a partially open configuration for the joint
310. As illustrated, the frame member 306 includes a curve 334 that
extends for less than a complete loop.
[0047] FIGS. 4A and 4B provide an additional embodiment of the
valve 400 according to the present disclosure. The valve 400
includes the valve frame 402 and valve leaflet 404 coupled to the
valve frame 402. The valve frame 402 also includes frame members
406 that define a frame cell 408 having joints 410, as discussed
herein. FIG. 4A provides an illustration of the valve 400 in an
undeployed state, where as FIG. 4B provides an illustration of the
valve 400 in a deployed state (e.g., where the joints 410 are in
their second stable equilibrium state 426). As illustrated, the
joints 410 have a partially open configuration with a curve
434.
[0048] The joints 410 illustrated in FIGS. 4A and 4B also include
an opening 435 defined by the valve frame 402. In one embodiment,
the openings 435 defined by the valve frame 402 can be used to
advance the joints 410 of the valve frame 402 from the first stable
equilibrium state through the unstable equilibrium state to the
second stable equilibrium state. In one embodiment, this transition
can occur as one or more of the joints 410 are drawn towards each
other, as will be discussed herein.
[0049] The valve frame 402 has an elongate tubular structure with a
proximal end 412 and a distal end 414. In one embodiment, the frame
cell 408 of the present disclosure can be positioned so as to
provide both the proximal and distal ends 412, 414 of the valve
frame 402. Other configurations are possible, as discussed
herein.
[0050] As illustrated, the joints 410 are located on the frame
member 406 such that as the joints 410 transition to the second
stable equilibrium state the size (e.g., length) of the perimeter
of the valve frame 402 increases. In other words, the joints 410
are located on the frame member 406 in such a way as to cause the
valve frame 402 to radially increase in size as the joints 410 move
toward the second stable equilibrium state. In one embodiment, the
valve frame 402 increases its perimeter size as the frame cell 408
change shape during the joint 410 transition. As will be
appreciated, some change to the longitudinal dimension of the valve
frame 402 may occur as the perimeter dimension changes.
[0051] For the various embodiments, the valve frame 402 can be
self-expanding, as discussed herein. For the various embodiments,
the frame member 406 can also have similar and/or different
cross-sectional geometries along its length, as discussed herein.
The circulatory valve 400 can further include one or more
radiopaque markers (e.g., tabs, sleeves, welds), as discussed
herein.
[0052] FIG. 5 provides an additional embodiment of the valve 500
according to the present disclosure. The valve 500 includes the
valve frame 502 and valve leaflet 504 coupled to the valve frame
502. The valve frame 502 also includes frame members 506 that
define a frame cell 508 having joints 510, as discussed herein. As
illustrated, while the frame cells 508 are located at the proximal
end 512 and distal end 514 of the valve frame 502 not every frame
cell 508 includes a joint 510. In addition, joints 510 in the frame
cells 508 have different relative locations along the frame member
506.
[0053] FIG. 5 also illustrates that the valve frame 502 has frame
members 506 that define a predefined frame design 540 that extends
between the frame cells 508. As illustrated, the predefined frame
design 540 and the frame cells 508 have a different configuration.
Selection of the predefined frame design 540 can be based on a
number of factors. Such factors include, but are not limited to,
the location where the valve 500 is to be implanted, the size of
the valve 500, the material(s) used to form the valve frame 502 of
the valve 500, among others. Examples of other useful frame designs
include those illustrated in co-pending U.S. patent application
Ser. No. 60/899,444 entitled "Percutaneous Valve, System and
Method" (atty docket number 07-00015P).
[0054] FIG. 6 provides an additional embodiment of the present
disclosure in which the frame cell 608 includes a lock mechanism
644. In the various embodiments, the lock mechanism 644 can engage
to prevent the frame cell 608 from transitioning from the second
stable equilibrium state. As illustrated, the lock mechanism 644 of
the present embodiment can include a first engagement member 646
and a second engagement member 648 that can engage so as to lock
together.
[0055] In one embodiment, the first and second engagement members
646, 648 on the frame cell 608 engage to lock together as the frame
cell 608 moves from the unstable equilibrium state 624 to the
second stable equilibrium state 626. As illustrated, the first
engagement member 646 extends from one of the joints 610 (e.g., a
first joint), while the second engagement member 648 extends from
another of the joint 610 (e.g., a second joint) of the frame cell
608. Alternatively, the engagement members can extend from portions
of the compliant segments 616 of the frame cell 608. For the
various embodiments, the locking mechanism 644 can allow the second
state 626 to be something other than a local potential energy
minimum, as it better ensures the frame cell 608 does not return to
its first stable equilibrium state 622.
[0056] The lock mechanism 644 used with the frame cell 608 can take
a number of different forms and configurations. For example, first
engagement member 646 of the lock mechanism 644 can include a shaft
having a ball tip. The second engagement member 648 can have a
socket to receive and lock the ball tip of the shaft.
Alternatively, the first engagement member 646 of the lock
mechanism 644 can include a shaft having a hook. The second
engagement member 648 can have a loop or member segment to receive
and engage the hook to lock the frame cell 608. In one embodiment,
the loop of the second engagement member 648 could be either the
loop of the joint 610 or a portion of the frame member 606, which
are opposite to and functionally aligned with the hook.
[0057] FIG. 7 provides an illustration of a deployment mechanism
750 used to transition the joint 710 the first stable equilibrium
state 722 through the unstable equilibrium state 724 to the second
stable equilibrium state 726. As illustrated, the deployment
mechanism 750 can be used to apply a force to draw the joints 710
towards each other. Upon reaching the second stable equilibrium
state 726, the deployment mechanism 750 can be removed from the
joints 710 of the frame cell 708.
[0058] For the present embodiment, the deployment mechanism 750
includes a push tube 752 having a lumen 754, and a deployment
thread 756 that extends through the lumen 754. The push tube 752
includes a distal end 758 that can abut a first of the joints 710.
The deployment thread 756 extends from the lumen 754 and loops
through a second of the joints 710 positioned across from the first
of the joints 710. A pulling force 760 can be applied through the
deployment thread 756 and/or a pushing force 762 can be applied
through the push tube 752 to apply force to draw the joints 710
towards each other.
[0059] Upon reaching the second stable equilibrium state 726, the
deployment thread 756 can be removed from the joint 710 by pulling
on a first end of thread 756 to allow the second end of the thread
756 to pass through the joint 710. The thread 756 and the push tube
752 can then be removed from the frame cell 708. Other ways of
removing the thread 756 from the frame joint 710 are also
possible.
[0060] For the various embodiments, the deployment thread 756 can
have a number of different configurations. For example, the
deployment thread 756 can be a monofilament (i.e., a single strand
of material). Alternatively, the deployment thread 756 can have a
multistrand configuration. For example, the deployment thread 756
having multiple strands can have a woven, a braided, and/or a
twisted configuration. Combinations of these configurations are
also possible.
[0061] The deployment thread 756 can also have a multilayer
construction, where the deployment thread 756 includes a core that
is surrounded by one or more layers. The core and layers of the
deployment thread 756 can be formed of different materials and/or
the same materials having different desired properties. In
addition, the deployment thread 756 can further include a coating
that does not necessarily constitute a "layer" (i.e., a material
that imbeds or integrates into the layer on which it is applied).
Such layers and/or coatings can impart properties to the deployment
thread 756 such as hardness and/or lubricity, among others.
[0062] The deployment thread 756 can be formed of a number of
materials. Such materials can have a sufficient tensile strength
and yield point to resist stretching so as to allow the frame cells
of the present disclosure to be deployed as discussed herein.
Examples of such materials include, but are not limited to,
polymers such as nylon(s), acetal, Pebax, PEEK, PTFE, polyamide,
polypyrol, and Kevlar. Alternatively, the deployment thread 756 can
be formed of metal and/or metal alloys, such as stainless steel,
elgioly, nitinol, and titanium. Other polymers, metals and/or metal
alloys are also possible. The thread 756 could also be coated with
a lubricious material, such as a hydrophilic coating. The materials
of the deployment thread 756 also include combinations of these
materials in one or more of the configurations as discussed
herein.
[0063] The push tube 752 can formed from a number of different
materials. Materials include metal(s), metal alloys, and polymers,
such as PVC, PE, POC, PET, polyamide, mixtures, and block
co-polymers thereof. In addition, the push tube 752 can have a wall
thickness and a lumen diameter sufficient to allow the deployment
thread 756 to slide longitudinally through the lumen 754 and to
have sufficient column strength to apply the pushing force 762, as
discussed herein.
[0064] FIGS. 8A and 8B illustrate a cross-sectional view of an
embodiment of a system 866 according to the present disclosure.
System 866 includes circulatory valve 800, as described herein,
releasably joined to an elongate delivery catheter 868. The system
866 also includes a retractable sheath 870, where the circulatory
valve 800 is releasably positioned between the sheath 870 and the
delivery catheter 868. For example, FIG. 8A illustrates an
embodiment in which the retractable sheath 870 is positioned around
at least a portion of the delivery catheter 868 to releasably hold
the valve 800 in an undeployed state. FIG. 8B illustrates an
embodiment in which the sheath 870 has been retracted relative the
delivery catheter 868 to allow the valve 800 to expand to its
partially deployed state.
[0065] In the example, the delivery catheter 868 includes an
elongate body 872 having a proximal end 874 and a distal end 876. A
lumen 878 extends through the proximal and distal ends 874, 876. In
one embodiment, the lumen 878 receives a guidewire for guiding the
placement of the circulatory valve 800 in the vasculature.
[0066] For the various embodiments, the elongate delivery catheter
868 also includes a distal tip 880. For the various embodiments,
the distal tip 880 has a conical configuration, where the tip 880
has a smaller diameter portion near the distal end 876 of the of
the delivery catheter 868 as compared to the proximal portion of
the tip 880. The distal tip 880 can also include a recessed lip 882
in which a distal portion of the retractable sheath 870 can
releasably seat. In one embodiment, seating the distal portion of
the retractable sheath 870 in the recessed lip 882 helps to hold
the valve 800 in its undeployed state.
[0067] The retractable sheath 870 can move longitudinally (e.g.,
slide) relative the delivery catheter 868 to allow the circulatory
valve 800 to expand from its undeployed state towards the first
stable equilibrium state. In one embodiment, moving the retractable
sheath 870 relative the delivery catheter 868 can be accomplished
by pulling, a proximal portion 884 of the sheath 870 relative a
proximal portion 886 of the delivery catheter 868.
[0068] The system 866 also includes push tubes 852 and deployment
thread 856 for a deployment mechanism, as discussed herein. As
illustrated, the push tubes 852 are positioned between the sheath
870 and the delivery catheter 868. The push tubes 852 also include
a proximal portion 888 from which the tubes 852 can be moved
longitudinally relative the sheath 870 and the delivery catheter
868. In one embodiment, the proximal portion 888 allows a user to
apply a pushing force through the tubes 852 to the joints 810, as
discussed herein. For the various embodiments, the deployment
thread 856 extends from the lumen 854 of the push tubes 852, where
both the deployment thread 856 and at least the distal end 859 of
the push tubes 852 releasably engage the joints 810 of the frame
cell 808.
[0069] As illustrated in FIG. 8B, the circulatory valve 800 expands
to its first stable equilibrium state, as discussed herein, after
the retractable sheath 870 has been retracted relative the valve
800. The push tubes 852 are illustrated as bending with the valve
800 in its first stable equilibrium state. The push tubes 852 are
also illustrated as abutting the first of the joint 810 while the
deployment thread 856 loops through the second of the joint 810 for
the frame cell 808. Force applied through the deployment threads
856 and/or the push tubes 852 can then be used to transition the
valve 800 from the first stable equilibrium state to the second
stable equilibrium state, as discussed herein.
[0070] Embodiments of the system 866 can further include an
expandable filter that forms a portion of the retractable sheath.
Examples of such an embodiment can be found in co-pending U.S.
patent application Ser. No. 12/012,911, entitled "Percutaneous
Valve, System and Method" (docket number 07-00015US), which is
hereby incorporated by reference in its entirety.
[0071] Each of the delivery catheter 868, the retractable sheath
870 can be formed of a number of materials. Materials include
polymers, such as PVC, PE, POC, PET, polyamide, mixtures, and block
co-polymers thereof. In addition, each of the delivery catheter 868
and the retractable sheath 870 can have a wall thickness and an
inner diameter sufficient to allow the structures to slide
longitudinally relative each other, as described herein, and to
maintain the circulatory valve 800 in a compressed state, as
discussed herein.
[0072] As discussed herein, applying force between the push tubes
852 and the deployment thread 856 allows the frame cells 808 to
transition to the second stable equilibrium state (e.g., the
deployed state). Additional approaches to transitioning frame cells
808 to the second stable equilibrium state (e.g., the deployed
state) are also possible. For example, two or more deployment
threads could be used for each frame cell to draw the joints into
the second stable equilibrium state. Alternatively, the frame cells
could abut the retractable sheath at a proximal end of the stent,
while deployment threads are used to draw the joints into the
second stable equilibrium state. Other configurations are also
possible.
[0073] In an additional embodiment, seating of the valve 800 in its
deployed state within the vasculature can be assisted by radially
expanding the valve 800 with a balloon catheter. For example, FIG.
8C provides an illustration of the valve 800 after the push tubes
and the deployment thread have been removed from the valve frame
802. A balloon catheter 892 having an inflatable balloon 894 can be
positioned in the lumen of the valve 800. The balloon 894 can be
inflated with fluid supplied by an inflation device 896 through
catheter lumen 898 in fluid communication with the balloon 892. In
one embodiment, the balloon 894 can have a "dog bone" shape, where
the bulbous ends of the balloon are aligned with the frame cells
808 of the valve 800. The balloon 892 can then contact and radially
expand the valve frame 802 to better ensure that the valve 800 is
deployed.
[0074] In an additional embodiment, the circulatory valve 800 can
further include a sealing material 801 positioned on the periphery
of the valve frame 802. In one embodiment, once implanted the
tissue the sealing material 801 can swell due the presence of
liquid to occupy volume between the valve frame 802 and the tissue
on which the valve 800 has been implanted so as to prevent leakage
of the liquid around the outside of the circulatory valve 800.
[0075] A variety of suitable materials for the sealing material 801
are possible. For example, the sealing material 801 can be selected
from the general class of materials that include polysaccharides,
proteins, and biocompatible gels. Specific examples of these
polymeric materials can include, but are not limited to, those
derived from poly(ethylene oxide) (PEO), polyethylene terephthalate
(PET), poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA),
poly(vinylpyrrolidone) (PVP), poly(ethyloxazoline) (PEOX)
polyaminoacids, pseudopolyamino acids, and polyethyloxazoline, as
well as copolymers of these with each other or other water soluble
polymers or water insoluble polymers. Examples of the
polysaccharide include those derived from alginate, hyaluronic
acid, chondroitin sulfate, dextran, dextran sulfate, heparin,
heparin sulfate, heparan sulfate, chitosan, gellan gum, xanthan
gum, guar gum, water soluble cellulose derivatives, and
carrageenan. Examples of proteins include those derived from
gelatin, collagen, elastin, zein, and albumin, whether produced
from natural or recombinant sources.
[0076] The embodiments of the valve described herein may be used to
replace, supplement, or augment valve structures within one or more
lumens of the body. For example, embodiments of the present
invention may be used to replace an incompetent cardiac valve of
the heart, such as the aortic, pulmonary and/or mitral valves of
the heart. In one embodiment, the native cardiac valve can either
remain in place (e.g., via a valvuloplasty procedure) or be removed
prior to implanting the circulatory valve of the present
disclosure.
[0077] In addition, positioning the system having the valve as
discussed herein includes introducing the system into the
cardiovascular system of the patient using minimally invasive
percutaneous, transluminal techniques. For example, a guidewire can
be positioned within the cardiovascular system of a patient that
includes the predetermined location. The system of the present
disclosure, including the valve as described herein, can be
positioned over the guidewire and the system advanced so as to
position the valve at or adjacent the predetermined location. In
one embodiment, radiopaque markers on the catheter and/or the
valve, as described herein, can be used to help locate and position
the valve.
[0078] The valve can be deployed from the system at the
predetermined location in any number of ways, as described herein.
In one embodiment, valve of the present disclosure can be deployed
and placed in any number of cardiovascular locations. For example,
valve can be deployed and placed within a major artery of a
patient. In one embodiment, major arteries include, but are not
limited to, the aorta. In addition, valves of the present invention
can be deployed and placed within other major arteries of the heart
and/or within the heart itself, such as in the pulmonary artery for
replacement and/or augmentation of the pulmonary valve and between
the left atrium and the left ventricle for replacement and/or
augmentation of the mitral valve. The circulatory valve can also be
implanted in the leg veins (e.g., iliac, femoral, great saphenous,
popliteal, and superficial saphenous). Other locations are also
possible.
[0079] As discussed herein, the circulatory valve can be deployed
in a staged fashion. In the first stage, the valve is held in its
undeployed state (e.g., compressed state) by the retractable
sheath. The retractable sheath can then be moved (e.g., retracting
the sheath) to allow the valve to radially expand from the
undeployed state to the first stable equilibrium state. The joints
of the valve frame can then be transitioned from the first stable
equilibrium state through the unstable equilibrium state to the
second stable equilibrium state to deploy the circulatory valve, as
discussed herein. In an additional embodiment, the circulatory
valve can also be radially expanded with an inflatable balloon to
set the circulatory valve in the deployed state.
[0080] Once implanted, the valve can provide sufficient contact
with the body lumen wall to prevent retrograde flow between the
valve and the body lumen wall, and to securely locate the valve and
prevent migration of the valve. The valve described herein also
display sufficient flexibility and resilience so as to accommodate
changes in the body lumen diameter, while maintaining the proper
placement of valve. As described herein, the valve can engage the
lumen so as to reduce the volume of retrograde flow through and
around valve. It is, however, understood that some leaking or fluid
flow may occur between the valve and the body lumen and/or through
valve leaflets.
[0081] While the present invention has been shown and described in
detail above, it will be clear to the person skilled in the art
that changes and modifications may be made without departing from
the spirit and scope of the invention. For example, the pulling
mechanism illustrated herein could be used to mechanically expand a
valve frame of other types of self-expanding stents and/or valve
frames to enlarge the cross-sectional size (e.g., the diameter) to
its fullest dimension. As such, that which is set forth in the
foregoing description and accompanying drawings is offered by way
of illustration only and not as a limitation. The actual scope of
the invention is intended to be defined by the following claims,
along with the full range of equivalents to which such claims are
entitled. In addition, one of ordinary skill in the art will
appreciate upon reading and understanding this disclosure that
other variations for the invention described herein can be included
within the scope of the present invention.
[0082] In the foregoing Detailed Description, various features are
grouped together in several embodiments for the purpose of
streamlining the disclosure. This method of disclosure is not to be
interpreted as reflecting an intention that the embodiments of the
invention require more features than are expressly recited in each
claim. Rather, as the following claims reflect, inventive subject
matter lies in less than all features of a single disclosed
embodiment. Thus, the following claims are hereby incorporated into
the Detailed Description, with each claim standing on its own as a
separate embodiment.
* * * * *