U.S. patent application number 13/404118 was filed with the patent office on 2012-06-14 for methods and devices for delivery of prosthetic heart valves and other prosthesis.
Invention is credited to Brian Beckey, David C. Forster, Scott Heneveld, Brandon Walsh.
Application Number | 20120150289 13/404118 |
Document ID | / |
Family ID | 38445028 |
Filed Date | 2012-06-14 |
United States Patent
Application |
20120150289 |
Kind Code |
A1 |
Forster; David C. ; et
al. |
June 14, 2012 |
Methods and Devices for Delivery of Prosthetic Heart Valves and
Other Prosthesis
Abstract
Prosthetic valves and their component parts are described, as
are prosthetic valve delivery devices and methods for their use.
The prosthetic valves are particularly adapted for use in
percutaneous aortic valve replacement procedures. The delivery
devices are particularly adapted for use in minimally invasive
surgical procedures. The preferred delivery device includes a
catheter having a deployment mechanism attached to its distal end,
and a handle mechanism attached to its proximal end. A plurality of
tethers are provided to selectively restrain the valve during
deployment. A number of mechanisms for active deployment of
partially expanded prosthetic valves are also described.
Inventors: |
Forster; David C.; (Menlo
Park, CA) ; Heneveld; Scott; (Whitmore, CA) ;
Walsh; Brandon; (Syracuse, UT) ; Beckey; Brian;
(Woodside, CA) |
Family ID: |
38445028 |
Appl. No.: |
13/404118 |
Filed: |
February 24, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11363961 |
Feb 27, 2006 |
8147541 |
|
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13404118 |
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Current U.S.
Class: |
623/2.11 |
Current CPC
Class: |
A61F 2/2439 20130101;
A61F 2/243 20130101; A61F 2/9522 20200501; A61F 2/2412
20130101 |
Class at
Publication: |
623/2.11 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A method for performing an interventional surgical procedure,
comprising: introducing a catheter into the vasculature of a
patient, said delivery catheter having an inner shaft and an outer
sheath substantially surrounding said inner shaft; causing relative
rotation between said inner shaft and said outer sheath.
2. The method of claim 1, further comprising the step of: deploying
a prosthetic device at a treatment location within the patient.
3. The method of claim 2, wherein said treatment location is a
blood vessel.
4. The method of claim 2, wherein said prosthetic device is a
prosthetic heart valve.
5. The method of claim 4, wherein said catheter comprises a
deployment mechanism operatively connected to said outer sheath and
said inner shaft, said deployment mechanism adapted to maintain
said prosthetic heart valve in a contracted state and to transform
said prosthetic heart valve to a fully expanded state.
6. The method of claim 5, wherein said deployment mechanism
includes a first tube having a plurality of slots attached to said
outer sheath.
7. The method of claim 6, wherein said deployment mechanism
includes a second tube having a plurality of slots attached to said
inner shaft.
8. The method of claim 6, further comprising a plurality of pins
attached to said inner shaft.
9. The method of claim 8, wherein rotation of said outer sheath
relative to said inner shaft causes rotation of said first tube
relative to said plurality of pins, thereby transforming said
prosthetic valve from its contracted state to at least a partially
expanded state.
10. The method of claim 8, further comprising the step of:
retracting said outer sheath proximally relative to said inner
shaft.
11. The method of claim 10, wherein said retracting step allows
said prosthetic valve to transform to its fully expanded state.
12. The method of claim 11, wherein said deployment mechanism
includes at least one restraining member adapted to restrain said
prosthetic valve in its fully expanded state.
13. The method of claim 12, wherein said restraining member
comprise one or more tethers.
14. The method of claim 12, further comprising the step of: using
said at least one restraining member to reposition said prosthetic
device at said treatment location.
15. The method of claim 12, further comprising the step of: using
said at least one restraining member to return said prosthetic
valve to its contracted state within said catheter.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/363,961, filed Feb. 27, 2006, which claims
the benefit of U.S. Provisional Application Ser. No. 60/548,731,
filed Feb. 27, 2004, and U.S. Provisional Application Ser. No.
60/559,199, filed Apr. 1, 2004, each of which is hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to medical devices
and methods. More particularly, the present invention relates to
methods and devices for delivering and deploying prosthetic heart
valves and similar structures using minimally invasive surgical
methods.
BACKGROUND OF THE INVENTION
[0003] Diseases and other disorders of the heart valve affect the
proper flow of blood from the heart. Two categories of heart valve
disease are stenosis and incompetence. Stenosis refers to a failure
of the valve to open fully, due to stiffened valve tissue.
Incompetence refers to valves that cause inefficient blood
circulation by permitting backflow of blood in the heart.
[0004] Medication may be used to treat some heart valve disorders,
but many cases require replacement of the native valve with a
prosthetic heart valve. Prosthetic heart valves can be used to
replace any of the native heart valves (aortic, mitral, tricuspid
or pulmonary), although repair or replacement of the aortic or
mitral valves is most common because they reside in the left side
of the heart where pressures are the greatest. Two primary types of
prosthetic heart valves are commonly used, mechanical heart valves
and prosthetic tissue heart valves.
[0005] The caged ball design is one of the early mechanical heart
valves. The caged ball design uses a small ball that is held in
place by a welded metal cage. In the mid-1960s, another prosthetic
valve was designed that used a tilting disc to better mimic the
natural patterns of blood flow. The tilting-disc valves had a
polymer disc held in place by two welded struts. The bileaflet
valve was introduced in the late 1970s. It included two
semicircular leaflets that pivot on hinges. The leaflets swing open
completely, parallel to the direction of the blood flow. They do
not close completely, which allows some backflow.
[0006] The main advantages of mechanical valves are their high
durability. Mechanical heart valves are placed in young patients
because they typically last for the lifetime of the patient. The
main problem with all mechanical valves is the increased risk of
blood clotting.
[0007] Prosthetic tissue valves include human tissue valves and
animal tissue valves. Both types are often referred to as
bioprosthetic valves. The design of bioprosthetic valves are closer
to the design of the natural valve. Bioprosthetic valves do not
require long-term anticoagulants, have better hemodynamics, do not
cause damage to blood cells, and do not suffer from many of the
structural problems experienced by the mechanical heart valves.
[0008] Human tissue valves include homografts, which are valves
that are transplanted from another human being, and autografts,
which are valves that are transplanted from one position to another
within the same person.
[0009] Animal tissue valves are most often heart tissues recovered
from animals. The recovered tissues are typically stiffened by a
tanning solution, most often glutaraldehyde. The most commonly used
animal tissues are porcine, bovine, and equine pericardial
tissue.
[0010] The animal tissue valves are typically stented valves.
Stentless valves are made by removing the entire aortic root and
adjacent aorta as a block, usually from a pig. The coronary
arteries are tied off, and the entire section is trimmed and then
implanted into the patient.
[0011] A conventional heart valve replacement surgery involves
accessing the heart in the patent's thoracic cavity through a
longitudinal incision in the chest. For example, a median
sternotomy requires cutting through the sternum and forcing the two
opposing halves of the rib cage to be spread apart, allowing access
to the thoracic cavity and heart within. The patient is then placed
on cardiopulmonary bypass which involves stopping the heart to
permit access to the internal chambers. Such open heart surgery is
particularly invasive and involves a lengthy and difficult recovery
period.
[0012] A less invasive approach to valve replacement is desired.
The percutaneous implantation of a prosthetic valve is a preferred
procedure because the operation is performed under local
anesthesia, does not require cardiopulmonary bypass, and is less
traumatic. Current attempts to provide such a device generally
involve stent-like structures, which are very similar to those used
in vascular stent procedures with the exception of being larger
diameter as required for the aortic anatomy, as well as having
leaflets attached to provide one way blood flow. These stent
structures are radially contracted for delivery to the intended
site, and then expanded/deployed to achieve a tubular structure in
the annulus. The stent structure needs to provide two primary
functions. First, the structure needs to provide adequate radial
stiffness when in the expanded state. Radial stiffness is required
to maintain the cylindrical shape of the structure, which assures
the leaflets coapt properly. Proper leaflet coaption assures the
edges of the leaflets mate properly, which is necessary for proper
sealing without leaks. Radial stiffness also assures that there
will be no paravalvular leakage, which is leaking between the valve
and aorta interface, rather than through the leaflets. An
additional need for radial stiffness is to provide sufficient
interaction between the valve and native aortic wall that there
will be no valve migration as the valve closes and holds full body
blood pressure. This is a requirement that other vascular devices
are not subjected to. The second primary function of the stent
structure is the ability to be crimped to a reduced size for
implantation.
[0013] Prior devices have utilized traditional stenting designs
which are produced from tubing or wire wound structures. Although
this type of design can provide for crimpability, it provides
little radial stiffness. These devices are subject to "radial
recoil" in that when the device is deployed, typically with balloon
expansion, the final deployed diameter is smaller than the diameter
the balloon and stent structure were expanded to. The recoil is due
in part because of the stiffness mismatches between the device and
the anatomical environment in which it is placed. These devices
also commonly cause crushing, tearing, or other deformation to the
valve leaflets during the contraction and expansion procedures.
Other stenting designs have included spirally wound metallic
sheets. This type of design provides high radial stiffness, yet
crimping results in large material strains that can cause stress
fractures and extremely large amounts of stored energy in the
constrained state. Replacement heart valves are expected to survive
for many years when implanted. A heart valve sees approximately
500,000,000 cycles over the course of 15 years. High stress states
during crimping can reduce the fatigue life of the device. Still
other devices have included tubing, wire wound structures, or
spirally wound sheets formed of nitinol or other superelastic or
shape memory material. These devices suffer from some of the same
deficiencies as those described above.
[0014] A number of improved prosthetic heart valves and scaffolding
structures are described in co-pending U.S. patent application Ser.
No. 11/066,126, entitled "Prosthetic Heart Valves, Scaffolding
Structures, and Methods for Implantation of Same," filed Feb. 25,
2005, ("the '126 application") which application is hereby
incorporated by reference in its entirety. Several of the
prosthetic heart valves described in the '126 application include a
support member having a valvular body attached, the support member
preferably comprising a structure having three panels separated by
three foldable junctions. The '126 application also describes
several delivery mechanisms adapted to deliver the described
prosthetic heart valve. Although the prosthetic heart valves and
delivery systems described in the '126 application represent a
substantial advance in the art, additional delivery systems and
methods are desired, particularly such systems and methods that are
adapted to deliver and deploy the prosthetic heart valves described
therein.
SUMMARY OF THE INVENTION
[0015] The present invention provides methods and devices for
deploying prosthetic heart valves and other prosthetic devices in
body lumens. The methods and devices are particularly adapted for
use in percutaneous aortic valve replacement. The methods and
devices may also find use in the peripheral vasculature, the
abdominal vasculature, and in other ducts such as the biliary duct,
the fallopian tubes, and similar lumen structures within the body
of a patient. Although particularly adapted for use in lumens found
in the human body, the apparatus and methods may also find
application in the treatment of animals.
[0016] Without intending to limit the scope of the methods and
devices described herein, the deployment devices and methods are
particularly adapted for delivery of prosthetic heart valves and
scaffolding structures identical or similar to those described in
the '126 application described above. A particularly preferred
prosthetic heart valve includes a generally cylindrical support
structure formed of three segments, such as panels, interconnected
by three foldable junctions, such as hinges, a representative
embodiment of which is illustrated in FIG. 1A of the '126
application, which is reproduced herein as FIG. 1A. The exemplary
prosthetic valve 30 includes a generally cylindrical support member
32 made up of three generally identical curved panels 36 and a
valvular body 34 attached to the internal surface of the support
member. Each panel includes an aperture 40 through which extends a
plurality of interconnecting braces 42 that define a number of
sub-apertures 44, 46, 48, 50. A hinge 52 is formed at the junction
formed between each pair of adjacent panels. The hinge may be a
membrane hinge comprising a thin sheet of elastomeric material 54
attached to the external edge 56 of each of a pair of adjacent
panels 36.
[0017] Turning to FIG. 1B-C, a method for transforming a prosthetic
valve from its expanded state to its contracted state is
illustrated. These Figures show a three-panel support member
without a valvular body attached. The method for contracting a full
prosthetic valve, including the attached valvular body, is similar
to that described herein in relation to the support member alone.
As shown in FIG. 1B, each of the panels 36 is first inverted, by
which is meant that a longitudinal centerline 80 of each of the
panels 36 is forced radially inward toward the central longitudinal
axis 82 of the support member. This action is facilitated by having
panels formed of a thin, resilient sheet of material having
generally elastic properties, and by the presence of the hinges 52
located at the junction between each pair of adjacent panels 36.
During the inversion step, the edges 56 of each of the adjacent
pairs of panels fold upon one another at the hinge 52. The
resulting structure, shown in FIG. 1B, is a three-vertex 58 star
shaped structure, referred to herein as a "tri-star" shape. Those
skilled in the art will recognize that a similar procedure may be
used to invert a four (or more) panel support member, in which case
the resulting structure would be a four- (or more) vertex star
shaped structure.
[0018] The prosthetic valve 30 may be further contracted by curling
each of the vertices 58 of the star shaped structure to form a
multi-lobe structure, as shown in FIG. 1C. As shown in that Figure,
each of the three vertices 58 is rotated toward the center
longitudinal axis 82 of the device, causing each of the three
folded-upon edges of the adjacent pairs of panels to curl into a
lobe 84. The resulting structure, illustrated in FIG. 1C, is a
"tri-lobe" structure that represents the fully contracted state of
the prosthetic valve. Those skilled in the art will recognize that
a similar procedure may be used to fully contract a four (or more)
panel support member, in which case the resulting structure would
be a four- (or more) lobed structure.
[0019] The foregoing processes are performed in reverse to
transform the prosthetic valve from its contracted state to its
expanded state. For example, beginning with the prosthetic valve in
its "tri-lobe" position shown in FIG. 1C, the three vertices 58 may
be extended radially to achieve the "tri-star" shape shown in FIG.
1B. The "tri-star" shape shown in FIG. 1B is typically not stable,
as the panels 36 tend to spontaneously expand from the inverted
shape to the fully expanded shape shown in FIG. 1A unless the
panels are otherwise constrained. Alternatively, if the panels do
not spontaneously transition to the expanded state, it will
typically only require a slight amount of force over a relatively
short amount of distance in order to cause the panels to fully
expand. For example, because of the geometry of the three panel
structure, a structure having an expanded diameter of about 21 mm
would be fully expanded by insertion of an expanding member having
a diameter of only 16 mm into the interior of the structure. In
such a circumstance, the 16 mm diameter member would contact the
centerline of each panel and provide sufficient force to cause each
panel to transform from the inverted shape shown in FIG. 1B to the
fully expanded shape shown in FIG. 1A. This is in contrast to a
typical "stent"-like support structure, which requires an expanding
member to expand the stent to its full radial distance.
[0020] Additional details of this and other embodiments of the
prosthetic heart valve and scaffolding structures are provided in
the '126 application, to which the present description refers. It
is to be understood that those prosthetic heart valves and
scaffolding structures are only examples of such valves and
prosthetic devices that are suitable for use with the devices and
methods described herein. For example, the present devices and
methods are suitable for delivering valves and prosthetic devices
having any cross-sectional or longitudinal profile, and is not
limited to those valves and devices described in the '126
application or elsewhere.
[0021] Turning to the deployment devices and methods, in one aspect
of the present invention, a delivery catheter for prosthetic heart
valves and other devices is provided. The delivery catheter is
preferably adapted for use with a conventional guidewire, having an
internal longitudinal lumen for passage of the guidewire. The
delivery catheter includes a handle portion located at a proximal
end of the catheter, a deployment mechanism located at the distal
end of the catheter, and a catheter shaft interposed between and
operatively interconnecting the handle portion and the deployment
mechanism. The deployment mechanism includes several components
that provide the delivery catheter with the ability to receive and
retain a prosthetic valve or other device in a contracted, delivery
state, to convert the prosthetic device to a partially expanded
state, and then to release the prosthetic valve completely from the
delivery device. In several preferred embodiments, the deployment
mechanism includes an outer slotted tube, a plurality of wrapping
pins attached to a hub and located on the interior of the slotted
tube, and a plurality of restraining members that extend through
the wrapping pins to the distal end of the catheter. Each of the
deployment mechanism components is individually controlled by a
corresponding mechanism carried on the handle portion of the
catheter. The deployment mechanism preferably also includes a
nosecone having an atraumatic distal end.
[0022] In several particularly preferred embodiments, the
restraining members comprise tethers in the form of a wire, a
cable, or other long, thin member made up of one or more of a metal
such as stainless steel, metallic alloys, polymeric materials, or
other suitable materials. A particularly preferred form of the
tethers is suture material. In several embodiments, the tethers are
adapted to engage the guidewire that extends distally past the
distal end of the delivery catheter. The tethers preferably engage
the guidewire by having a loop, an eyelet, or other similar
construction at the distal end of the tether. Optionally, the
tether is simply looped around the guidewire and doubles back to
the catheter handle. Thus, the tethers are released when the
guidewire is retracted proximally into the delivery catheter. In
still other embodiments, the tethers may be released from the
guidewire by actuation of a member carried on the handle mechanism
at the proximal end of the catheter. In still other embodiments, a
post or tab is provided on the guidewire, and the tether engages
the post or tab but is able to bend or break free from the post or
tab when a proximally-oriented force is applied to the tethers.
[0023] In a second aspect of the present invention, several
optional active deployment mechanisms are described. The active
deployment mechanisms are intended to convert a prosthetic valve,
scaffolding structure, or similar device from an undeployed,
partially deployed, or not-fully deployed state to its fully
expanded state. Several of the active deployment mechanisms take
advantage of the fact that the preferred prosthetic valves and
scaffolding structures require only a small amount of force applied
any of a large number of points or locations on the valve or
structure in order to cause the valve to fully expand. Exemplary
embodiments of the active deployment mechanisms include embodiments
utilizing expandable members that are placed into the interior of
the prosthetic valve and then expanded; embodiments that operate by
causing the hinges of the undeployed prosthetic valve to open,
thereby transitioning to the fully expanded state; embodiments that
include implements that engage one or more of the panels to cause
the panel to expand to its deployed state; and other embodiments
described herein.
[0024] Other aspects, features, and functions of the inventions
described herein will become apparent by reference to the drawings
and the detailed description of the preferred embodiments set forth
below.
DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A is a perspective view of a prosthetic valve suitable
for use by the delivery catheter of the present invention.
[0026] FIG. 1B is a top view of a partially contracted support
member illustrating inverted panels to form a "tri-star" shape.
[0027] FIG. 1C is a top view of a fully contracted support member
illustrating inverted and curled panels to form a "tri-lobe"
shape.
[0028] FIG. 2 is a perspective view of a delivery catheter in
accordance with the present invention.
[0029] FIG. 3 is a perspective view of a deployment mechanism of
the delivery catheter of FIG. 2.
[0030] FIG. 3A is a cross-sectional view of the deployment
mechanism shown in FIG. 3.
[0031] FIG. 3B is a perspective view of several of the internal
components included in the deployment mechanism shown in FIG.
3.
[0032] FIG. 3C is a perspective view of a wrapping pin
stabilizer.
[0033] FIGS. 3D-F are cross-sectional views of wrapping pins and
their associated tethers.
[0034] FIG. 3G is another perspective view of a wrapping pin
stabilizer.
[0035] FIG. 4 is a perspective view of a handle mechanism of the
delivery catheter shown in FIG. 2.
[0036] FIG. 5 is a cross-sectional view of the handle mechanism
shown in FIG. 4.
[0037] FIG. 6 is a side view of the handle mechanism of the
delivery catheter shown in FIG. 2, illustrating several positions
corresponding with steps performed during use of the delivery
catheter to deliver a prosthetic device.
[0038] FIG. 7 is a perspective view of the deployment mechanism,
shown with a prosthetic valve in a star shape and with the slotted
tube fully advanced.
[0039] FIG. 8 is a perspective view of the deployment mechanism,
shown with a prosthetic valve in a star shape with the wrapping
pins fully advanced and with the slotted tube retracted.
[0040] FIG. 9 is a perspective view of the deployment mechanism,
shown with a prosthetic valve in a star shape with the wrapping
pins and the slotted tube retracted.
[0041] FIG. 9A is a closeup view of the nosecone and guidewire
shown in FIG. 9, showing detail of the manner in which a tether is
looped over the guidewire.
[0042] FIG. 10 is a perspective view of the deployment mechanism,
shown with a prosthetic valve in expanded shape with tethers
retaining the valve in place.
[0043] FIG. 11 is a perspective view of the deployment mechanism,
shown with a prosthetic valve in expanded shape, and showing the
guidewire and tethers withdrawn to release the valve.
[0044] FIGS. 12A-B are side cross-sectional and end views,
respectively, of a portion of the distal end of a delivery
catheter, illustrating an eyelet formed on the ends of each
tether.
[0045] FIGS. 12C-D are side cross-sectional views of a first
wrapping pin having no recess, and a second wrapping pin having an
eyelet recess formed therein.
[0046] FIG. 12E is an end cross-sectional view of a prosthetic
valve partially restrained by three dual tethers.
[0047] FIGS. 12F-G are illustrations of two methods for selectively
attaching dual tethers to a guidewire.
[0048] FIG. 13 is a side view of a portion of a delivery catheter
illustrating a valve stop formed on each tether.
[0049] FIGS. 14A-B are side partial cross-sectional views of a
portion of a delivery catheter illustrating tethers including
linkage members. FIG. 14A shows a valve in its expanded state, and
FIG. 14B shows the valve in its "tri-star" state.
[0050] FIG. 15 is a side view in partial cross-section of a
delivery catheter illustrating tethers having loops that are routed
through throughholes in the nosecone.
[0051] FIGS. 16A-B are a side view in partial cross-section and an
end view showing a slotted nosecone.
[0052] FIG. 17 is a side view in partial cross-section of a
delivery catheter illustrating tethers having primary and secondary
sections.
[0053] FIGS. 18A-B are side views of a portion of a prosthetic
valve having loops for engaging a tether to prevent migration.
[0054] FIGS. 19A-D are side views of several embodiments of
wrapping pins.
[0055] FIGS. 20A-B are side views in partial cross-section showing
a pair (out of three) of articulating wrapping pins, forming a
gripper mechanism.
[0056] FIGS. 21A-B are an end perspective view in partial
cross-section and a top view in partial cross-section of a slotted
tube.
[0057] FIG. 21C is a side cross-sectional view of a slotted tube
having runners and a valve panel in its contracted state.
[0058] FIGS. 22A-B are a perspective view and an end view,
respectively, of an alternative deployment mechanism for a delivery
catheter.
[0059] FIG. 23A is an illustration of a shape set nosecone
shaft.
[0060] FIG. 23B is a cross-sectional end view of the shape set
nosecone shaft of FIG. 23A.
[0061] FIG. 23C is a side view of the shape set nosecone shaft of
FIG. 23A showing the tensioning member in tension.
[0062] FIGS. 24A-C illustrate a side view in partial cross-section
and two end views, respectively, of an active deployment mechanism
for deploying a valve, in accordance with the present
invention.
[0063] FIGS. 25A-C illustrate side views in partial cross-section
of another active deployment mechanism for deploying a valve, in
accordance with the present invention.
[0064] FIGS. 26A-E illustrate several embodiments of active
deployment mechanism employing inflatable members, such as
balloons.
[0065] FIGS. 27A-B illustrates another embodiment of an active
deployment mechanism employing inflatable members, such as
balloons.
[0066] FIG. 28 illustrates an active deployment mechanism utilizing
a roller and pincher.
[0067] FIGS. 29A-B illustrate an active deployment mechanism
utilizing a wedge.
[0068] FIG. 30 illustrates an active deployment mechanism utilizing
a torsion spring.
[0069] FIGS. 31A-B illustrate an active deployment mechanism
utilizing a membrane balloon mounted on a slotted tube.
[0070] FIG. 32 illustrates an active deployment mechanism utilizing
a plurality of linkages able to be expanded by an inflatable
member.
[0071] FIGS. 33A-B illustrate an active deployment mechanism
utilizing an expansion balloon mounted within the nosecone of a
delivery catheter.
[0072] FIGS. 34A-C illustrate an active deployment mechanism
utilizing a yoke and linkage system adapted to extend radially
outward upon actuation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0073] Before the present invention is described, it is to be
understood that this invention is not limited to particular
embodiments described, as such may, of course, vary. It is also to
be understood that the terminology used herein is for the purpose
of describing particular embodiments only, and is not intended to
be limiting, since the scope of the present invention will be
limited only by the appended claims.
[0074] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which these inventions belong.
Although any methods and materials similar or equivalent to those
described herein can also be used in the practice or testing of the
present invention, the preferred methods and materials are now
described. All publications mentioned herein are incorporated
herein by reference to disclose and describe the methods and/or
materials in connection with which the publications are cited.
[0075] It must be noted that as used herein and in the appended
claims, the singular forms "a", "an", and "the" include plural
referents unless the context clearly dictates otherwise.
[0076] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present invention is not entitled to antedate such publication
by virtue of prior invention. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0077] As will be apparent to those of skill in the art upon
reading this disclosure, each of the individual embodiments
described and illustrated herein has discrete components and
features which may be readily separated from or combined with the
features of any of the other several embodiments without departing
from the scope or spirit of the present inventions.
A. Delivery Devices and Methods of Use
[0078] Devices for delivering prosthetic valves and other devices
to a treatment location in a body lumen are described below, as are
methods for their use. The delivery devices are particularly
adapted for use in minimally invasive interventional procedures,
such as percutaneous aortic valve replacements. FIG. 2 illustrates
a preferred embodiment of the device, in the form of a delivery
catheter. The delivery catheter 100 includes a handle mechanism 102
located at the proximal end of the catheter, a deployment mechanism
104 located at the distal end of the device, and a shaft 106
extending between and interconnecting the handle mechanism 102 and
the deployment mechanism 104. The catheter 100 is preferably
provided with a guidewire lumen extending through the entire length
of the catheter, such that a guidewire 108 is able to extend
through the delivery catheter in an "over-the-wire" construction.
In an optional embodiment (not shown in the drawings), the catheter
100 is provided with a "rapid-exchange" construction whereby the
guidewire exits the catheter shaft through an exit port located
near the distal end of the catheter. The cross-sectional profile of
the deployment mechanism 104 and the shaft 106 are of a
sufficiently small size that they are able to be advanced within
the vasculature of a patient to a target location, such as the
valve root of one or more of the valves of the heart. A preferred
route of entry is through the femoral artery in a manner known to
those skilled in the art. Thus, the deployment mechanism 104 has a
preferred maximum diameter of approximately 24 Fr. It is
understood, however, that the maximum and minimum transverse
dimensions of the deployment mechanism 104 may be varied in order
to obtain necessary or desired results.
[0079] The deployment mechanism 104 is provided with components,
structures, and/or features that provide the delivery catheter with
the ability to retain a prosthetic valve (or other prosthetic
device) in a contracted state, to deliver the valve to a treatment
location, to convert the prosthetic valve to its deployed state (or
to allow the valve to convert to its deployed state on its own), to
retain control over the valve to make any necessary final position
adjustments, and to convert the prosthetic valve to its contracted
state and withdraw the valve (if needed). These components,
structures, and/or features of the preferred deployment mechanism
are described below.
[0080] Turning to FIGS. 3 and 3A, the deployment mechanism 104 is
shown in its fully contracted state for use when the mechanism 104
has not yet reached the target site within the body of a patient,
such as prior to use and during the delivery process. The
deployment mechanism 104 includes a slotted tube 110 that is
connected to an outer sheath 112 of the catheter shaft 106, such as
by way of the attachment collar 111 (shown in FIG. 3A). Thus,
longitudinal movement or rotation of the outer sheath 112 causes
longitudinal movement or rotation of the slotted tube 110. The
slotted tube 110 is a generally cylindrical body that includes a
plurality of longitudinal slots 114 that extend from the distal end
of the slotted tube 110 to near its proximal end. In the preferred
delivery catheter, the slotted tube 110 includes three slots 114
spaced equidistantly about the circumference of the slotted tube
110. The slots 114 have a length and width that are sufficient to
accommodate the extension of portions of the prosthetic valve 30
therethrough, as described more fully below in reference to FIG. 7,
described elsewhere herein. The slotted tube 110 is preferably
formed of stainless steel or other generally rigid material
suitable for use in medical devices or similar applications.
[0081] The deployment mechanism 104 may also include a retainer
ring 116 and a nosecone 118. Although the retainer ring 116 and
nosecone 118 are not necessary parts of the delivery catheter, each
of these components may provide additional features and
functionality when present. The nosecone 118 is located at the
distal end of the delivery catheter and is preferably provided with
a generally blunt, atraumatic tip 120 to facilitate passage of the
catheter through the patient's vasculature while minimizing damage
to the vessel walls. The nosecone 118 is preferably formed of any
suitable biocompatible material. In several preferred embodiments,
the nosecone is formed of a relatively soft elastomeric material,
such as a polyurethane, a polyester, or other polymeric or
silicone-based material. In other embodiments, the nosecone is
formed of a more rigid material, such as a plastic, a metal, or a
metal alloy material. The nosecone may be coated with a coating
material or coating layer to provide advantageous properties, such
as reduced friction or increased protection against damage. It is
also advantageous to provide the nosecone with an atraumatic shape,
at least at its distal end, or to form the nosecone 118 of
materials that will provide the atraumatic properties while still
providing structural integrity to the distal end of the device. The
nosecone 118 preferably includes a plurality of throughholes 122
that extend through the length of the nosecone to allow passage of
a plurality of tethers 124, which are described more fully below. A
pair of slots 119 are formed on the exterior of the nosecone 118.
The slots 119 provide a pair of surfaces for a wrench or other tool
to grasp the nosecone 118 to enable manual manipulation of the
nosecone 118, for purposes to be described below.
[0082] The retainer ring 116 is a generally cylindrically shaped
ring that is located generally between the slotted tube 110 and the
nosecone 118. More precisely, when the deployment mechanism 104 is
in the fully contracted state shown in FIGS. 3 and 3A, the retainer
ring 116 preferably overlaps a ledge 126 formed on the distal end
of the slotted tube 110. Alternatively, the inner diameter of the
retainer ring 116 may be formed slightly larger than the outer
diameter of the slotted tube 110, thereby allowing the distal ends
of the slotted tube 110 to slide within the retainer ring 116
without the need for a ledge 126. In this way, the retainer ring
116 prevents the distal ends of the slotted tube 110 from bowing
outward due to pressure caused by the prosthetic valve being stored
within the deployment mechanism 104.
[0083] The proximal end of the retainer ring 116 engages a bearing
128 that is formed integrally with the nosecone 118, and that
allows the nosecone 118 to rotate inside and independently from the
retainer ring 116. As described below, the slotted tube 110 is
rotated relative to the nosecone shaft 136 and the wrapping pins
130 during some operations of the deployment mechanism, primarily
during the expansion and contraction of the prosthetic valve.
Without the bearing 128 (or a suitable alternative), the prosthetic
valve would tend to bind up within the deployment mechanism and
prevent relative rotation between the slotted tube 110 and the
wrapping pins 130. Thus, the provision of the bearing 128 engaged
with the retainer ring 116 facilitates this rotation of the slotted
tube 110, which engages the retainer ring 116.
[0084] Additional features of the interior of the deployment
mechanism are illustrated in the cross-sectional view shown in
FIGS. 3A-G. A plurality of fixed wrapping pins 130 are attached to
a wrapping pin hub 132 and extend longitudinally from the hub 132
toward the distal end of the catheter. The preferred embodiment of
the delivery catheter includes three wrapping pins 130, although
more or fewer are possible. The hub 132 is attached to a wrapping
pin shaft 134 that extends proximally from the hub 132 beneath the
outer sheath 112 of the catheter shaft 106. Thus, movement or
rotation of the wrapping pin shaft 134 causes longitudinal movement
or rotation of the hub 132 and the three wrapping pins 130. A
wrapping pin stabilizer 133 is slidably attached to the outer
surfaces of each of the wrapping pins 130. The pin stabilizer 133
is a generally disc-shaped member having a center hole 133a and
three equally spaced throughholes 133b to accommodate the three
wrapping pins 130. As described below, in certain orientations of
the deployment mechanism 104, the pin stabilizer 133 provides
support and stability to the wrapping pins 130 extending distally
from the wrapping pin hub 132.
[0085] Turning to FIGS. 3D-F, in several of the preferred
embodiments, the tethers 124 extend through or are otherwise
engaged with the wrapping pins 130. The Figures illustrate several
methods by which this is done. In the closed configuration, shown
in FIG. 3D, the wrapping pin 130 includes a central lumen 131a
through which the tether 124 extends. The lumen 131a extends
through the length of the wrapping pin 130 and through the hub 132,
allowing the tether to extend proximally to the handle mechanism
102. In the open configuration, shown in FIG. 3E, the wrapping pin
130 includes a channel 131b formed on its underside. The tether 124
is able to be received in the channel 131b, although it is not
necessarily retained therein. In the guided configuration, shown in
FIG. 3F, the wrapping pin 130 includes a channel 131b formed on its
underside. A tether guide 135 is located in the channel 131b, and
is preferably attached to the handle housing 152 by welding,
adhesive, or other suitable method. The tether 124 is routed
through the guide 135, and is thereby retained within the guide
135.
[0086] A nosecone shaft 136 is located internally of the wrapping
pin shaft 134. The nosecone 118 is attached to the nosecone shaft
136, and the nosecone shaft 136 is slidably received through the
wrapping pin hub 132. However, the nosecone shaft 136 is fixed to
the wrapping pin stabilizer 133. Thus, longitudinal movement of the
nosecone shaft 136 causes longitudinal movement of the nosecone 118
and the pin stabilizer 133, independent of any of the other
components of the deployment mechanism 104. However, rotation of
the handle housing 152 causes rotation of the nosecone 118, the pin
stabilizer 133, and the wrapping pins 130. The nosecone shaft 136
is hollow, thereby defining a guidewire lumen 137 through its
center.
[0087] A plurality of wrapping pin sockets 138 are formed on the
proximal side of the nosecone 118. Each socket 138 is generally
cylindrical and has a size adapted to receive the distal portion of
a wrapping pin 130 therein. When the distal ends of the wrapping
pins 130 are engaged with their respective sockets 138, the sockets
138 provide support and rigidity to the wrapping pins 130. This
support and rigidity is particularly needed during the wrapping and
unwrapping of the prosthetic valve, as described more fully below.
During those operations, a large amount of strain is imparted to
each of the wrapping pins 130, which strain is absorbed in part by
the sockets 138 formed in the nosecone 118. Each socket 138 is also
provided with a hole 140 that provides access to a respective
throughhole 122 in the nosecone 118. As described more fully below,
this provides a passage for a tether 124 that is contained within
each wrapping pin 130 to extend through the hole 140 in each
socket, through the throughhole 122 to the distal end of the
nosecone 118.
[0088] Although it is not shown in the cross-sectional view in FIG.
3A, a prosthetic valve 30 such as the type described herein in
relation to FIGS. 1A-C--and in the '126 application--may be
retained on the wrapping pins 130 in the interior of the slotted
tube 110. A suitable method for loading the valve 30 into the
device will be described below. The valve 30 is retained in a
contracted, multi-lobe state (see, e.g., FIG. 1C) in which each
"lobe" is generally wrapped around a respective wrapping pin 130,
and held in place there by engagement with the interior surface of
the slotted tube 110.
[0089] Turning now to FIGS. 4-6, the handle mechanism 102 will be
described. The handle mechanism 102 includes a slotted tube grip
150 that is fixedly connected to the outer sheath 112 while being
slidably and rotatably mounted on a handle housing 152. The handle
housing 152 is a generally cylindrical hollow shaft. The slotted
tube grip 150 is preferably formed of or covered with a corrugated
polymer or rubber material to provide the ability to easily grasp
and manipulate the grip 150. Similarly, a wrapping pin grip 154,
also preferably formed of or covered with a corrugated polymer or
rubber material, is slidably mounted to the handle housing 152. The
wrapping pin grip 154 includes a bolt 156 that extends through a
slot 158 formed in the handle housing 152, to engage the proximal
end of the wrapping pin shaft 134. A tether grip 160 is slidably
mounted over the proximal end of the handle housing 152. The tether
grip 160 is also generally cylindrical, having a slightly larger
diameter than the handle housing 152, thereby allowing the tether
grip 160 to slide over the handle housing 152 in a telescoping
manner. A locking screw 162 extends through a slot 164 formed in
the tether grip 160 and into the side of the handle housing 152
near its proximal end. The locking screw 162 allows the user to fix
the position of the tether grip 160 relative to the handle housing
152 by screwing the locking screw 162 down.
[0090] Three tether clamps 166 extend from the proximal end of the
tether grip 160. Each tether clamp 166 is independently clamped to
a tether 124 that extends through the catheter to its distal end,
as explained in more detail herein. Each tether clamp 166 also
includes a spring mechanism (not shown) that provides independent
tensioning for each tether 124. The proximal end of the nosecone
shaft 136 extends out of the proximal end of the tether grip 160,
between the three tether clamps 166, terminating in a small
cylindrical nosecone shaft grip 168. The guidewire 108 is shown
extending out of the proximal end of the nosecone shaft 136.
[0091] The preferred embodiment of the valve delivery catheter so
described is intended to be used to deliver and deploy a prosthetic
device, such as a prosthetic heart valve, to a patient using
minimally invasive surgical techniques. Turning to FIGS. 6-11, a
representative method of use of the device will be described. The
device is intended to be introduced to the vasculature of a patient
over a standard guidewire that has been previously introduced by
any known technique, with access via the femoral artery being the
preferred method. The guidewire is advanced to the treatment
location under x-ray or other guidance, such as to the root of a
heart valve, such as the aortic valve. Once the guidewire is in
place, the valve delivery catheter 100 is advanced over the
guidewire until the deployment mechanism 104 reaches the treatment
location. During the delivery process, the deployment mechanism is
in the fully contracted state shown, for example, in FIGS. 2 and
3.
[0092] Once the deployment mechanism 104 is located near the
treatment location, the valve deployment process begins. The
guidewire 108 is initially left in place through the deployment
process, and is not withdrawn until a particular point in the
process defined below. The valve deployment process includes
manipulation of the slotted tube grip 150, wrapping pin grip 154,
and tether grip 160 located on the handle mechanism 102, which
cause a series of manipulations of the slotted tube 110, wrapping
pin hub 132 and wrapping pins 130, and the tethers 124, in order to
release and deploy the prosthetic valve in a manner that provides
control during deployment and the ability to precisely position,
re-position, and (if necessary) retrieve the prosthetic valve at
any time during the deployment process. FIG. 6 illustrates several
of the positions of the components of the handle mechanism 102
during the preferred deployment process. These positions correspond
to several of the delivery steps illustrated in FIGS. 7-11.
[0093] As noted elsewhere herein, it is possible to provide valves
that are contracted into other sizes and orientations (such as two
lobes or four or more lobes), which would also include a delivery
catheter having a different number of slots in the slotted tube 110
and a different number of wrapping pins 130. For clarity, the
present description will focus entirely upon the valve 30 having
three panels 36 and three hinges 52, and a delivery catheter 100
having three slots 114 in the slotted tube 110 and three wrapping
pins 130.
[0094] Turning to FIGS. 6 and 7, the first step in deploying the
prosthetic valve 30 is to partially expand the contracted valve
from the "tri-lobe" shape (see FIG. 1C) to the "tri-star" shape
(see FIG. 1B). This is done by causing relative rotation between
the slotted tube 110 and the wrapping pins 130. As shown in FIG. 6,
this is done by rotating the slotted tube grip 150 around the
longitudinal axis of the delivery catheter, thereby causing the
slotted tube 110 to rotate around the wrapping pins 130, which are
maintained stationary. This relative rotation is facilitated by the
provision of the bearing 128 in the nosecone 118 of the deployment
mechanism 104, as illustrated in FIG. 3A. As the slotted tube 110
rotates relative to the wrapping pins 130, each of the vertices 58
of the prosthetic valve 30 is caused to extend outward through its
respective slot 114 in the slotted tube 110. Rotation of the
slotted tube grip 150 is stopped when the valve 30 achieves the
"tri-star" shape shown in FIG. 7. At all times during the process
up to this point, the adjustable components on the handle mechanism
(i.e., the tether grip 160, the wrapping pin grip 154, and the
slotted tube grip 150) are maintained in position "a", wherein the
tether grip 160 is in its fully retracted position, and the
wrapping pin grip 154 and slotted tube grip 150 are each in their
fully advanced positions.
[0095] Turning next to FIGS. 6 and 8, the next step in the
deployment process is to retract the slotted tube 110 to further
expose the prosthetic valve 30. This is done by retracting the
slotted tube grip 150 to position "b" (FIG. 6) while maintaining
the wrapping pin grip 154 and tether grip 160 in the same position
"b". Retracting the slotted tube 110 causes the valve 30 to become
more exposed, but the valve 30 is maintained in the "tri-star"
shape by the wrapping pins 130 which continue to engage each of the
three panels 36 of the valve 30. Although not shown in FIG. 8, the
distal ends of the wrapping pins 130 also remain seated in the
wrapping pin sockets 138 located in the proximal-facing portion of
the nosecone 118. In this "b" position, the wrapping pin stabilizer
133 is located just proximally of the valve 30 and is just distal
of the wrapping pin hub 132.
[0096] Next, turning to FIGS. 6 and 9, the wrapping pins 130 are
retracted by retracting the wrapping pin grip 154 to position "c"
(as shown in the Figure, transitioning from position "b" to
position "c" requires no adjustment of either the slotted tube grip
150 or the tether grip 160). Retracting the wrapping pins 130
causes the wrapping pins 130 to become disengaged from the valve 30
and to retract to the interior of the slotted tube 110. The
wrapping pin stabilizer 133, which is fixed to the nosecone shaft
136, slides along the length of the wrapping pins 130 until maximum
retraction of the wrapping pins 130, which corresponds to the
position shown in FIG. 9, with the stabilizer 133 near the distal
ends of each of the wrapping pins 130. In this position, the
stabilizer 133 provides support and rigidity to the nosecone shaft
136, which is otherwise only supported by the wrapping pin hub 132.
As shown, for example, in FIG. 9, the stabilizer 133 effectively
decreases the cantilever length of the nosecone shaft 136, thereby
providing it with increased stability. The stabilizer 133 also
serves as a backing member for the prosthetic valve 30, preventing
the valve 30 from moving proximally as the wrapping pins 130 are
retracted. Further, the stabilizer 133 also serves as a guide for
the tethers 124 as they extend from the distal ends of the wrapping
pins 130.
[0097] The valve remains in the "tri-star" position due to the
presence of the tethers 124, the spacing of which is maintained by
the holes in the stabilizer 133 through which the wrapping pins 130
and tethers 124 extend. In the preferred embodiment shown in FIGS.
9 and 9A, a tether 124 extends through each of the wrapping pins
130, through the hole 140 in the socket 138, through the
throughholes 122 in the nosecone 118, and is looped around the
guidewire 108 on the distal side of the nosecone 118. The tethers
124 each extend proximally through and within the catheter shaft
106 and is received and retained in its respective tether clamp 166
near the proximal end of the catheter 100. In the position shown in
FIG. 9, the tethers 124 are all maintained sufficiently taut that
they retain the valve 30 in the "tri-star" orientation shown in the
Figure. This corresponds with position "c" of the tether grip 160
relative to the handle housing 152, shown in FIG. 6.
[0098] In an alternative embodiment, the tethers 124 may be
tensioned by manipulation of the distal connection of the tethers
124 to the guidewire 108. For example, rotation of the nosecone
shaft 136 will cause the tethers 124 to wrap around the guidewire
108, thereby providing tension to the tethers 124. Other suitable
methods for tensioning the tethers 124 are also contemplated, as
will be understood by those skilled in the art.
[0099] Turning next to FIGS. 6 and 10, expansion of the valve 30 is
obtained by loosening the tethers 124 that otherwise hold the valve
30 in the "tri-star" position. This transition is achieved by
advancing the tether grip 160 to position "d", as shown in FIG. 6.
(Note: Transitioning from position "c" to position "d" requires no
adjustment of either the slotted tube grip 150 or the wrapping pin
grip 154). Advancement of the tether grip 160 relative to the
handle housing 152 creates slack in the tethers 124, which slack is
taken up by the radial expansion of the valve 30. In the typical
deployment, the valve 30 will automatically fully expand to the
deployment position shown in FIG. 10 when the tension is released
from the tethers 124. For those situations in which the valve 30
does not automatically expand, or when the valve only partially
expands, one or more alternative mechanisms and/or methods may be
utilized to obtain full expansion. Several of these preferred
mechanisms and methods are described below in Section B.
[0100] It is significant that, in the position shown in FIG. 10,
the tethers 124 no longer interfere with the expansion of the valve
30, but they remain in control of the valve 30. In this position,
it is possible to make any final positional adjustments of the
valve 30, if necessary. This can be done by simply advancing or
withdrawing the catheter 100, which tends to drag or push the valve
30 along with it. This may also be facilitated by slight
advancement of the wrapping pin grip 154 and/or retraction of the
tether grip 160, each of which actions will tend to apply tension
to the tethers 154. In this manner, the valve position may be
adjusted by the user while the valve is in its fully expanded
state, under control of the tethers 124.
[0101] Alternatively, the valve 30 may be partially or fully
contracted once again by increasing the tension on the tethers 124,
as by retracting the tether grip 160 relative to the handle housing
152. (I.e., moving from position "d" to position "c" in FIG. 6). If
necessary, the valve 30 may be fully contracted by retracting the
tether grip 160, and then the deployment mechanism 104 may be fully
restored to the undeployed position by simply reversing the above
steps, in order. (I.e., moving to position "c", then position "b",
then position "a"). This reversal of the process includes a step of
advancing the wrapping pins 130 back over the contracted valve
panels as the valve 30 is maintained in the "tri-star" shape. This
process is facilitated by the presence of the tethers 124, which
act as guides for the wrapping pins 130 to "ride up" over the edges
of the valve panels under the guidance of the tethers 124. Once the
wrapping pins 130 are in place, the slotted tube 110 is advanced
over the valve 30, with each of the vertices of the valve
"tri-star" extending through its respective slot 114. The slotted
tube 110 is then rotated relative to the wrapping pins 130 and
valve 30, causing the valve to transition to the fully contracted
"tri-lobe" shape fully contained within the slotted tube 110. At
that point, the delivery catheter may be removed from the patient
without deploying the valve 30. Any or all of these adjustment or
removal steps may be taken, depending upon the clinical need or
depending upon any situation that may arise during the deployment
procedure.
[0102] Turning to FIGS. 6 and 11, assuming that the valve 30 is
placed in its final position and is ready to be released, the valve
is released from the delivery catheter 100 by retracting the
guidewire 108 to a position such that the distal end of the
guidewire 108 no longer extends past the distal end of the nosecone
118 of the delivery catheter 100. At this point, the tethers 124
are released from their engagement with the guidewire 108.
Preferably, the tethers 124 are then retracted at least into the
wrapping pins 130, and may alternatively be fully retracted through
and from the proximal end of the delivery catheter 100. This is
reflected as handle position "f" in FIG. 6, in which the tether
grip 160 is retracted at least to its initial position, and no
change is made to the positions of either the wrapping pin grip 154
or the slotted tube grip 150. As shown in FIG. 11, the valve 30 is
completely free from the delivery catheter 100. The nosecone 118
remains distal of the valve 30, and the nosecone shaft 136 extends
through the body of the valve 30.
[0103] To complete the delivery process, the delivery catheter is
preferably contracted to its pre-delivery state by advancing the
wrapping pins 130 into engagement with the nosecone 118 by
advancing the wrapping pin grip 154 on the handle back to position
"a", then by advancing the slotted tube 110 into engagement with
the retainer ring 116 by advancing the slotted tube grip 150 on the
handle back to position "a". At this point, the delivery catheter
100 may be removed from the patient, leaving the prosthetic valve
30 in place.
B. Variations in Construction, Components, and/or Features of
Delivery Device
[0104] Preferred delivery catheters and methods of use are
described above. A number of variations of several of the
components, features, and other aspects of the device have been
contemplated, and are described below.
[0105] Turning first to FIGS. 12A-B, an alternative method of
connecting the tethers 124 to the guidewire 108 is shown. In the
embodiment described above, the tethers 124 are looped over the
guidewire 108. In the embodiment shown in FIGS. 12A-B, each tether
124 has an eyelet 125 formed at its distal end. The eyelet 125 is
connected to the tether by an adhesive bond, or by crimping, or by
any other suitable method. Each eyelet 125 has a hole formed at its
distal end that is large enough to accommodate the guidewire 108
extending therethrough. The eyelet 125 may have a generally curved
shape to rest alongside the nosecone 118, and a terminal end that
is generally perpendicular to the longitudinal axis defined by the
guidewire 108.
[0106] Turning to FIGS. 12C-D, an optional recess 131 may be formed
in the distal end of each of the wrapping pins 130. The recess 131
is preferably formed having a shape and size to accommodate the
eyelet 125 that is optionally provided at the distal end of each of
the tethers 124. Accordingly, when no recess 131 is available (see,
e.g., FIG. 12C), the eyelet 125 may be unable to be withdrawn into
the lumen provided for passage of the tether 124. When a recess 131
is provided (see, e.g., FIG. 12D), the eyelet 125 is retracted into
the recess 131 and does not extend out of the distal end of the
wrapping pin 130.
[0107] FIG. 12E illustrates an embodiment including a plurality of
dual or redundant tethers 124a-b. As shown in the Figure, a pair of
tethers 124a-b are provided on each of the panels of the valve 30.
The dual tethers 124a-b may be provided to increase tether
strength, where needed, or to provide redundancy in the case of
failure of one of the tethers. FIGS. 12F and 12G illustrate two
possible methods for attaching the dual tethers 124a-b to a
guidewire 108. In the first method, shown in FIG. 12F, a collar 176
is formed near the distal ends of and is attached to both of the
tethers 124a-b near their distal ends, thereby forming a loop
through which the guidewire 108 extends. In this construction, the
loop will remain even if one of the tethers fails. In the second
method, shown in FIG. 12G, each of the tethers 124a-b includes a
separate attachment loop 178a-b, through which the guidewire 108
extends. In each method, the tethers 124a-b are released when they
are disengaged from the guidewire 108 in the manner described
above.
[0108] Turning to FIG. 13, a valve stop 142 may be provided on each
of the tethers 124. Each valve stop 142 is in the form of a small
cleat, barb, tab, or other transverse extension from the tether
124. The valve stop 142 is intended to provide another mechanism to
prevent the valve 30 from slipping or migrating relative to the
tethers 124 when the tethers 124 are in engagement with the valve
30. Thus, the valve stop 142 is located at a particular known
position on each tether 124 to provide an optimal amount of control
to the device 100 when the tethers 124 are engaged with the valve
30.
[0109] FIGS. 14A-B illustrate tethers formed of linkages 144 and
tether sections 146. Each tether includes an eyelet 125 at its
distal end connecting the tether to the guidewire 108. The eyelet
125 is connected directly to a first linkage member 144a, which may
comprise a relatively rigid member formed of a metallic material, a
rigid polymeric material, or the like. The linkage 144 is of a
length sufficient to accommodate the valve 30 in its expanded
state, as shown in FIG. 14A. The first linkage 144a is connected to
a tether section 146 that extends through the length of the valve
30, and then connects to a second linkage member 144b. The second
linkage member 144b then connects to another section of the tether
146, which extends proximally into the remainder of the delivery
catheter. Each linkage member 144a, 144b includes a pivot at each
end thereof, thereby enabling the linkage member 144a, 144b to
pivot relative to the member to which it is attached. Thus, when
the tethers are relaxed, the valve 30 is allowed to expand, as
shown in FIG. 14A. However, when the tethers are pulled taut, the
linkages 144a, 144b pivot, thereby causing the tethers to become
taut and to convert the valve to its "tri-star" shape, as shown in
FIG. 14B. Preferably, the nosecone 118 is provided with slots that
accommodate the first linkage members 144a when they are pulled
taut in the position shown in FIG. 14B.
[0110] FIG. 15 illustrates a slight variation of the preferred
embodiment described above. In this embodiment, the tethers 124
each include a loop 148 formed on their distal ends. Each loop 148
is adapted to engage the guidewire 108. The tethers 124, in turn,
are routed through throughholes 122 formed in the nosecone 118, as
described above. Each tether 124 is then routed through a lumen
formed in its respective wrapping pin 130. This particular routing
orientation provides a mechanical advantage over other routing
orientation because the tethers are captured by the nosecone 118
and wrapping pins 130 in close relation to the valve 30. This
orientation also results in less migration of the tethers from
side-to-side relative to the valve 30.
[0111] Turning next to FIGS. 16A-B, an alternative method for
routing the tethers 124 in and around the nosecone 118 is to
provide a plurality of slots 121 on the exterior of the nosecone
118. Each slot 121 is adapted to receive and retain a tether 124
when the tethers 124 are pulled taut. The slots 121 also allow the
tethers to arise out of and disengage from its respective slot 121,
for example, when the tethers 124 are slack and the valve 30
expands.
[0112] FIG. 17 illustrates another embodiment containing tethers
formed of two separate components, including a thick, or broad
primary tether 124a and a thin, or narrow secondary tether 124b.
The primary tether 124a may be formed of a round or flat wire, and
may be provided as either a straight component or it may be
provided with a degree of shape memory. The secondary tether 124b
may be made from a finer, smaller diameter material that is less
traumatic to the vessel when it is pulled from between the valve 30
and the vessel. The secondary tether 124b may also be more easily
retracted through the wrapping pins 130. Although a two-component
tether 124 is shown, it should be appreciated that three or more
components may also be incorporated to make up the tether 124 and
to obtain various performance characteristics.
[0113] Turning next to FIGS. 18A-B, a pair of loops 170 are shown
formed on the external surface of the valve 30. The loops 170 are
intended to provide an engagement member on the surface of the
valve 30 for the tethers 124 to engage to prevent the tethers 124
from migrating on the surface of the valve 30. For example, if the
tether 124 migrates from the centerline of a valve panel 36, it may
no longer have the ability to cause the valve panel 36 to invert or
to restrain it in its inverted shape. By providing the loops 170,
such migration of the tethers 124 is substantially prevented. It
will be appreciated that mechanisms other than loops 170 may also
be provided to restrain tether migration. For example, holes,
barbs, slots, bumps, or other members may be provided on the
surface or integrated into the body of the valve panel 36 to
substantially restrain tether migration. One or more such members
may be sufficient to provide sufficient restraining capability.
[0114] Turning to FIGS. 19A-D, several alternative wrapping pin
embodiments are illustrated. The alternative embodiments represent
several methods by which wrapping pin deflection may be overcome.
As shown, for example, in FIG. 19A, when the wrapping pin hub 132
is rotated to cause wrapping up of a prosthetic valve 30 by the
wrapping pins 130, an amount of torque "T" is imparted to the hub
132, and a corresponding deflecting force "F" is imparted to the
distal end of the wrapping pin 130. The deflecting force "F" tends
to cause the wrapping pin 130 to deflect in the direction of the
deflecting force "F", which tends to interfere with the wrapping
procedure. To counteract the deflection force, the wrapping pin 130
may be formed having a gradual curving shape, as shown in FIG. 19B,
to offset the deflection and to provide more even wrapping of the
valve 30. The degree and nature of the curvature will vary
depending upon the materials, sizes, and other properties of the
delivery device and the valve, although the curvature will
typically be directed toward the deflecting force. Alternatively,
the wrapping pin 130 may be attached to the hub 132 at a fixed
angle, or canted, as illustrated in FIG. 19C. Once again, the cant
angle may be determined and will vary. Another alternative is shown
in FIG. 19D, in which the wrapping pin 130 is provided with an
offset between its proximal and distal ends. Once again, the degree
of offset may be varied according to need for a given device.
[0115] Turning to FIGS. 20A-B, in several additional alternative
embodiments, the wrapping pins 330 are not fixed in shape or
orientation relative to the hub 332. In several such embodiments,
the wrapping pins 330 include articulating segments 331 connected
by rotating joints 332, thereby allowing each wrapping pin 330 to
move radially relative to the longitudinal axis of the device. The
concerted movement of the multiple wrapping pins 330 (three pins
being preferred, but more or fewer also being possible) allows the
structure to act as a gripper for manipulating the prosthetic valve
30. In the preferred embodiments, movement of each articulated
wrapping pin 330 is independently controlled, thereby allowing the
user to move each articulated wrapping pin 330 independently from a
position generally comparable to that of the fixed wrapping pins
330 illustrated in the drawings (see FIG. 20A), to a position
substantially radially outwardly spaced from the longitudinal axis
of the device (see FIG. 20B). Thus, the close-in position (FIG.
20A) is suitable for restraining the valve in its contracted or
"tri-star" shape, while the radially spaced position (FIG. 20B) is
suitable for releasing the valve to its expanded state, or for
retrieving the valve from its expanded state in order to transition
the valve back to its contracted state.
[0116] FIGS. 21A-B illustrate an alternative construction for the
slotted tube 110. In this construction, each of the longitudinal
members 180 forming the slotted tube 110 includes an internal base
portion 182 formed of a rigid material such as stainless steel or
other metallic material, or a rigid polymeric material. The base
portion 182 is intended to provide strength and resiliency to the
slotted tube 110 to perform its functions of receiving, retaining,
and manipulating the valve 30 in response to manipulations of the
components contained on the handle mechanism 102 of the delivery
catheter. Surrounding the base portion 182 of the slotted tube 110
are a number of air gaps 184 and/or filled sections 186 that are
filled with a more flexible, less rigid material relative to the
material forming the base portion 182. A wide variety of filler
materials are possible, including several polymeric material such
as polyurethane, or other soft materials such as one or more
silicone based materials. The purpose for the air gaps 184 and/or
filled portions 186 are to provide a less traumatic construction to
reduce the likelihood of causing damage to the valve 30 or any of
its panels 36 or hinges 52 while the valve is being loaded, stored,
or deployed. By providing an air gap 184 or filled sections 186 on
the edges of the longitudinal sections 180 of the slotted tube 110,
the valve 30 is more protected during roll-up or deployment of the
valve, during which time the edges of the longitudinal members 180
impose force against the valve panels 36 to cause them to roll up
within the deployment mechanism 104 or to deploy out of the slotted
tube 110.
[0117] Turning to FIG. 21C, another mechanism for protecting the
valve panels 36 while they are retained within the slotted tube 110
is comprised of a series of runners 190 formed on the
internal-facing surfaces of the longitudinal members 180 making up
the slotted tube 110. The runners 190 provide a raised surface upon
which the panels 36 will ride to minimize the contact between the
panels 36 and the slotted tube 110. The runners 190 also serve to
decrease friction between the two components and decrease the
amount of abrasion that is imparted to the panels.
[0118] FIGS. 22A-B illustrate another alternative construction for
a portion of the deployment mechanism 104 of the delivery catheter
100. In this alternative construction, the wrapping pins 130 are
not needed. Instead, an inner slotted tube 194 is provided
coaxially with and interior to the outer slotted tube 110. As the
inner slotted tube 194 is rotated relative to the outer slotted
tube 110, the valve 30 is converted from a "tri-star" shape to a
"tri-lobe" shape, as shown, for example, in FIG. 22A. Reversing the
relative rotation causes the valve 30 to extend out of the slots
formed in each of the inner slotted tube 194 and the outer slotted
tube 110 to form the "tri-star" shape shown in FIG. 22B. The valve
30 may then be deployed by retracting both the inner slotted tube
194 and the outer slotted tube 110 relative to the valve 30,
thereby allowing the valve to expand to its deployed state.
[0119] FIGS. 23A-C illustrate an optional shape set nosecone shaft
136. The shape set nosecone shaft 136 includes a pre-set shape
formed into the distal end of the nosecone shaft 136 to facilitate
the ability for the distal end of the delivery catheter 100 to pass
over the aortic arch. This is particularly useful when the delivery
catheter 100 is used for delivery of a prosthetic aortic valve. The
shape set shown in FIG. 23A is generally in the form of a
hook-shape, although other shapes is possible in order to improve
the performance of the catheter. The shape set is also useful to
stabilize the position of the catheter once it is delivered over
the aortic arch. The shape set may be imparted by any mechanical or
other method known to those skilled in the art. An optional
tensioning member 336 may be provided on the external surface of
the nosecone shaft 136. The tensioning member 336 is used to
straighten the curvature of the shape set nosecone shaft 136 under
the user's control. For example, as a tension force "T" is imparted
to the tensioning member 336, such as by the user pulling
proximally on the tensioning member 336 from the handle mechanism
102, the nosecone shaft 136 is straightened, as shown in FIG. 23C.
The operation of the tensioning member 336 thereby provides the
ability to manipulate the distal end of the delivery catheter 100
in a manner that provides an ability for the user to effectively
steer the catheter over difficult or tortuous portions of the
patient's vasculature. Other uses of the tensioning member 336 are
described elsewhere herein.
C. Active Deployment of Undeployed and not-Fully Deployed
Valves
[0120] Although typically a prosthetic valve 30 such as those
illustrated and described above in relation to FIGS. 1A-C--and
those described in the '126 application and elsewhere--will fully
deploy once it is released from the delivery catheter, it sometimes
occurs that the valve does not deploy, or does not fully deploy. In
most of these circumstances, the failure to deploy or to fully
deploy is due to the fact that one or more panels 36 of a
multi-panel valve 30 fails to change from its inverted state to its
expanded state. One such example is illustrated in FIG. 24B, in
which two panels 36 of a three-panel prosthetic valve 30 have
expanded, but the upper panel 36 remains in a partially inverted
state. Several mechanisms and methods for actively correcting these
undeployed and not-fully deployed valves are described herein.
[0121] Several of the described mechanisms take advantage of the
fact that, in most circumstances of non-full deployment, only a
point contact is needed to cause the valve to fully expand.
Accordingly, it may not be necessary to fully occlude the vessel in
order to cause the valve or similar prosthetic device to fully
expand. Thus, in most of the mechanisms and methods described,
fluid flow or perfusion is still allowed through the valve and
vessel as the active deployment procedure takes place. This is to
be distinguished from the deployment methods applicable to most
stent-like prosthetic devices in which fibrillation is induced to
decrease flow during the deployment procedure. No such fibrillation
is required for delivery and deployment of the prosthetic valves
and similar devices described herein, nor for the active deployment
mechanisms and methods described.
[0122] Turning to FIGS. 24A-C, a first such mechanism 200 includes
a collar 202 and a plurality of wire forms 204 extending proximally
from the collar 202. The mechanism 200 is intended to ride closely
along the nosecone shaft 136 on any of the embodiments of the
delivery catheter 100 described herein. As the mechanism 200 is
advanced distally, it will enter and pass through the body of the
partially-expanded valve 30. Once it is located there, the collar
202 may be retracted proximally, as shown by the arrow "A" in FIG.
24A, thereby causing the wire forms 204 to bow radially outward,
(see, e.g., FIGS. 24A and 24C), engaging any inverted panels 36 of
the valve 30 and causing them to expand to the fully expanded
state. Preferably, the collar 202 is retracted by a tether or other
control member that is connected to the collar 202 and that extends
proximally to the handle where it can be manipulated by the user.
Once the valve 30 is fully expanded, the collar 202 is advanced
distally to cause the wire forms 204 to return to their unbowed
state. The mechanism 200 may then be retracted into the delivery
catheter 100. In alternative embodiments, the collar 202 may be
provided with threads that engage threads formed on the nosecone
shaft 136. Any other engagement providing relative movement between
the collar 202 and the nosecone shaft 136 is also suitable.
[0123] As an alternative to the wire forms 204 shown in the above
embodiment, a continuous segment of metallic or polymeric material
having sufficient elasticity to expand and contract in the manner
shown may be used. Other alternatives including using only a single
band or material, or two, three, or more bands. Other alternative
constructions and materials capable of expanding and contracting in
the involved space internal of the undeployed or partially deployed
prosthetic valve 30 are also contemplated, and are suitable for use
as the active deployment mechanism 200 described herein.
[0124] Another alternative construction for the active deployment
mechanism is illustrated in FIGS. 25A-C. A partially deployed valve
30 includes an upper panel 36 that has not yet fully deployed. The
deployment mechanism 200 comprises a collar 212 and a plurality of
wire forms 214 extending proximally from the collar 212. Prior to
use, the collar 212 is located internally of the catheter shaft 106
along the nosecone shaft 136, and the wire forms 214 lie flat along
the nosecone shaft 136 proximally to the collar 212. (See FIG.
25A). The collar 212 is advanced distally through the partially
deployed valve 30 until the collar 212 engages the proximal side of
the nosecone 118, where further distal advancement is stopped. (See
FIG. 25B). As additional distal-oriented force is applied to the
mechanism 200, the wire forms 214 are caused to bow radially
outward within the valve 30 to cause the upper panel 36 to fully
deploy, as shown in FIG. 25C. The mechanism 200 is then collapsed
and retracted proximally.
[0125] Turning to FIGS. 26A-E, several alternative balloon-based
active deployment mechanism are described. The balloon-based
systems include use of a balloon or other expandable member to
cause an otherwise non-fully deployed valve 30 to expand to its
fully expanded state upon deployment. Preferably, each of the
balloons described herein includes an inflation lumen that is
communicatively connected to the handle mechanism 102 or otherwise
provided with a mechanism for selectively inflating the balloon(s)
as needed.
[0126] FIG. 26A illustrates a first embodiment in which a balloon
220 is provided internally of a prosthetic valve 30. The balloon
220 includes a pair of broad portions 222a that correspond with the
proximal and distal ends of the valve 30, and a narrowed waist
portion 222b that corresponds with the middle portion of the valve
30. The balloon 220 may optionally be provided in a fixed
relationship with the valve body, as illustrated in FIG. 26B,
wherein the balloon 220 is packaged with the valve 30 as the valve
30 is loaded into the delivery catheter and delivered to a
treatment location. Thus, if the valve 30 is found not to have
fully expanded after deployment, the balloon 220 may be inflated to
cause full deployment.
[0127] A number of optional balloon shapes and sizes are
illustrated in FIGS. 26C-E. For example, in FIG. 26C, a single
balloon 220 is shown having two large diameter portions 222a and a
narrow, or smaller diameter portion 222b connecting the other two
portions. In FIG. 26D, a single balloon 220 is shown, and would
preferably extend through the entire length of the valve 30. In
FIG. 26E, three separate balloons 220a-c are illustrated in an
offset-tangent arrangement. The offset-tangent arrangement provides
a number of benefits, including the ability to selectively inflate
only one or more of the balloons 220a-c depending upon which valve
panel 36 requires expansion. Also, the offset-tangent arrangement
removes the need to fully occlude the vessel, thereby allowing
fluid to flow around the balloon structure.
[0128] Turning to FIGS. 27A-B, in another alternative arrangement,
a pair of toroidal balloons 226 are attached to the external
surface of a prosthetic valve 30 near its proximal and distal ends,
respectively. The pair of toroidal balloons 226 may be selectively
expandable in order to actively deploy an otherwise non-fully
deployed prosthetic valve 30. Upon expansion of the valve, the
balloons 226 may then be deflated and left in place to serve as a
seal against the vessel wall 230, as shown in FIG. 27B.
Alternatively, the toroidal balloons 226 may be attached to the
internal wall of the prosthetic valve 30, and may then be
selectively detached from the valve 30 after the valve has been
fully deployed.
[0129] FIG. 28 illustrates another active deployment mechanism 234
that includes a roller member 236 and a pincher member 238, each of
which may be included on the distal end of a shaft that may be
included with, or separate from, the delivery catheter 100. The
roller 236 and pincher 238 advance along a panel 36 until the
components encounter a hinge 52. Because of the diameter of the
roller 236 relative to the hinge 52, when the roller 236 and
pincher 238 engage the hinge 52, they force the hinge 52 to open,
thereby causing the valve panel 36 to fully deploy.
[0130] FIGS. 29A-B illustrate yet another deployment mechanism 242
that includes a wedge-shaped member having an upper guide 244 and a
lower separator 246. As with the previous deployment mechanism 234,
the present embodiment 242 be included on the distal end of a shaft
that may be included with, or separate from, the delivery catheter
100. The wedge mechanism 242 is intended to be guided onto each of
the hinges 52 of the undeployed or not-fully deployed valve 30.
Because of the relative size and shape of the separator 246 portion
of the wedge, the separator 246 causes the hinges 52 to open,
thereby causing the valve panels 36 to expand to the fully deployed
state.
[0131] Turning next to FIG. 30, another deployment mechanism 250
includes a torsion spring 252 mounted to the internal surface of
the valve 30. The torsion spring 252 may be integrated into and/or
may form part of the hinge 52 of the valve 30, but is provided with
a pair of arms 254 that extend into the interior of the valve 30,
and which are biased to force the valve panels 36 radially outward
to fully deploy the valve 30. The torsion spring 252 may be formed
integrally with the valve 30, in which case it remains in place
after valve deployment.
[0132] Turning to FIGS. 31A-B, yet another active valve deployment
mechanism 256 includes a membrane balloon 258 formed on or attached
to the external surface of each of the longitudinal members 180 of
the slotted tube 110. The membrane balloons 258 are selectively and
independently inflatable, as needed to actively deploy one or more
undeployed panels of a prosthetic valve 30. As shown in FIG. 31A,
the slotted tube 110 is first inserted into the valve 30, then one
or more of the membrane balloons 258 is expanded. The expansion is
initially to a first state 260 in which the membrane balloon
engages the valve body panels 36, then, ultimately, to a second
state 262 corresponding with full valve deployment. After
deployment, the balloon may be deflated and the device removed from
the patient's vasculature.
[0133] Turning to FIG. 32, a still further alternative active valve
deployment mechanism 266 includes a plurality of (preferably three)
linkage members 268, each including a pivot 270 allowing the
linkage member to expand radially, such as under the expansion
force of an internal balloon 272 or other expandable member. Thus,
as the deployment mechanism 266 is inserted into the undeployed
prosthetic valve 30, it is able to be expanded by expanding or
inflating the balloon 272.
[0134] FIGS. 33A-B illustrate another active deployment mechanism
276 that incorporates a balloon 278 or other expandable member that
is formed within the internal volume of the nosecone 118. In its
undeployed state, shown in FIG. 33A, the balloon 278 does not
extend past the distal end of the nosecone 118. However, if needed
to expand the undeployed or not-fully deployed valve 30, the
balloon 278 is expanded, as shown in FIG. 33B, thereby expanding
the valve 30 to its expanded state.
[0135] FIGS. 34A-C illustrate an active deployment mechanism that
includes a yoke 282 that is slidably engaged over the nosecone
shaft 136. A set of rotating linkages 284a-f are connected to the
sliding yoke 282 such that, when the yoke 282 slides proximally
along the nosecone shaft 136, as shown by the arrows "A" in FIG.
34A, the linkages 284a-f extend radially outward from the shaft
136. In the preferred embodiment, the free ends 284d-f of each of
the linkages 284a-f are selectively attached to a respective panel
of the valve 30 by a temporary mechanism. For example, the free
ends 284d-f of the linkages may be attached to the valve panels by
the tethers 124, such that when the tethers 124 are retracted, the
valve panels are released from the linkages 284a-f. The nosecone
118 is preferably hollow to accommodate the mechanism prior to
deployment.
[0136] Another optional active deployment mechanism utilizes the
shape set nosecone shaft 136 and tensioning member 336 shown in
FIGS. 23A-C. In the case of a valve 30 that does not fully deploy,
it may be possible to manipulate the tensioning member 336 to cause
either the nosecone 118, the nosecone shaft 136, or some other
portion of the deployment mechanism 104 to engage the undeployed
portion of the valve sufficiently to cause it to fully deploy. In a
particularly preferred method, the tethers 124 associated with all
of the fully deployed panels are allowed to remain slack, while the
tether 124 associated with the undeployed panel is pulled taut to
apply tension to the tether. By doing so, the nosecone 118 and the
respective wrapping pin 130 are pulled to the respective distal and
proximal edges of the valve panel, creating a relatively rigid
linkage between the components. Once this is done, the tensioning
member 336 (or other suitable steering mechanism) is actuated in
order to cause the relatively rigid linkage to bias the
still-inverted panel radially outward to the expanded position.
This process may be repeated for each panel that is not fully
expanded.
[0137] Finally, another alternative active deployment mechanism is
to pressurize the aorta (or other treatment vessel) to cause the
tissue defining the vessel to expand, thereby providing an adequate
(increased) volume within which the valve 30 or other device is
able to expand to its fully expanded state. Pressurization of the
aorta (or other vessel) may be obtained by simply occluding the
vessel, or by actively pressuring the vessel using an external
source.
[0138] The preferred embodiments of the inventions that are the
subject of this application are described above in detail for the
purpose of setting forth a complete disclosure and for the sake of
explanation and clarity. Those skilled in the art will envision
other modifications within the scope and spirit of the present
disclosure. Such alternatives, additions, modifications, and
improvements may be made without departing from the scope of the
present inventions, which is defined by the claims.
* * * * *