U.S. patent application number 17/491247 was filed with the patent office on 2022-08-25 for prosthetic implant delivery device with introducer catheter.
The applicant listed for this patent is Speyside Medical LLC. Invention is credited to Gordon B. Bishop, Kevin C. Robin.
Application Number | 20220265424 17/491247 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220265424 |
Kind Code |
A1 |
Bishop; Gordon B. ; et
al. |
August 25, 2022 |
PROSTHETIC IMPLANT DELIVERY DEVICE WITH INTRODUCER CATHETER
Abstract
A delivery system and a method for deploying a cardiovascular
prosthetic implant using a minimally invasive procedure are
disclosed. The delivery system comprises an introducer catheter, a
delivery catheter having a proximal end and a distal end, and a
seal assembly, wherein an outer diameter of the distal end of the
delivery catheter is greater than an inner diameter of the distal
end of the introducer catheter.
Inventors: |
Bishop; Gordon B.; (Santa
Rosa, CA) ; Robin; Kevin C.; (Santa Rosa,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Speyside Medical LLC |
Pleasanton |
CA |
US |
|
|
Appl. No.: |
17/491247 |
Filed: |
September 30, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15233499 |
Aug 10, 2016 |
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17491247 |
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13777745 |
Feb 26, 2013 |
9445897 |
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15233499 |
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61640862 |
May 1, 2012 |
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61707744 |
Sep 28, 2012 |
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International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A delivery system for delivering a cardiovascular prosthetic
implant using a minimally invasive procedure, wherein the
deployment system comprises: an introducer catheter having a
proximal end and a distal end; a delivery catheter extending
through the introducer catheter, the delivery catheter having a
proximal end and a distal end extending beyond the distal end of
the introducer catheter; and a hemostasis seal assembly on a
proximal end of the introducer catheter; wherein an outer diameter
of the distal end of the delivery catheter is greater than an inner
diameter of the distal end of the introducer catheter, and wherein
the introducer catheter is preassembled about the delivery
catheter.
2. The delivery system of claim 1 further comprising a
cardiovascular prosthetic implant at the distal end of the delivery
catheter.
3. The delivery system of claim 2, wherein the cardiovascular
prosthetic implant comprises an inflatable cuff and a tissue
valve.
4. The delivery system of claim 1, further comprising at least one
link between the delivery catheter and the cardiovascular
prosthetic implant.
5. The delivery system of claim 1, wherein the inner diameter of
the distal end of the introducer is 16F or less.
6. The delivery system of claim 1, wherein the introducer catheter
includes an elongated tapered tip.
7. The delivery system of claim 1, wherein the introducer catheter
includes a tapered tip configured to transition between a first
enlarged length configuration and a second shorter
configuration.
8. The delivery system of claim 1, wherein the system further
comprises a long tip in a first configuration and a short tip in a
second configuration.
9. The delivery system of claim 1, wherein the system further
comprises a tip that has a straight configuration and a bent
configuration.
10. A delivery system for delivering a cardiovascular prosthetic
implant using a minimally invasive procedure, wherein the
deployment system comprises: a introducer catheter having a
proximal end and a distal end and a lumen extending from the
proximal end to the distal end of the introducer catheter, the
introducer catheter having an outer diameter defined by an outer
surface of the introducer catheter and an inner diameter defining
the through lumen; a delivery catheter extending through the
introducer catheter, the delivery catheter comprising a tubular
body having a proximal end and a distal end, the distal end
including a sheath jacket and stem portion extending proximally
from the sheath jacket, the sheath jacket having an outer surface
that defines an outer diameter of the sheath jacket, the outer
diameter of the sheath jacket being greater than the inner diameter
of the introducer catheter at the distal end of the introducer
catheter, the stem portion having an outer surface that defines an
outer diameter of the stem portion, the outer diameter of the stem
portion being smaller than the inner diameter of the introducer
catheter; and a cardiovascular prosthetic implant positioned at
least partially within the sheath jacket; and wherein the
introducer catheter is preassembled about the delivery
catheter.
11. The delivery system of claim 10, comprising a seal assembly at
a proximal end of the introducer catheter.
12. The delivery system of claim 10, wherein the cardiovascular
prosthetic implant comprises an inflatable cuff and a tissue
valve.
13. The delivery system of claim 10, including at least one
inflation lumen extending between an inflatable cuff and the
proximal end of the introducer catheter, the inflation lumen
extending through the delivery catheter.
14. The delivery system of claim 10, further comprising at least
one link between the delivery catheter and the cardiovascular
prosthetic implant.
15. The delivery system of claim 10, wherein the inner diameter of
the distal end of the introducer catheter is about 16F.
16. The delivery system of claim 10, comprising a tubing extending
through the delivery catheter and the cardiovascular prosthetic
implant.
17. The delivery system of claim 16, comprising a distal tip
coupled to a distal end of the tubing, the distal tip having a
maximum outside diameter that is approximately the same as the
outside diameter of the jacket sheath.
18. The delivery system of claim 10, wherein the sheath jacket is
coupled to a distal end of the stem portion.
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. The delivery system of claim 1, wherein the seal assembly
comprises a flush port.
27. The delivery system of claim 1, wherein the seal assembly can
be adjusted to maintain the position of the introducer catheter
relative to the delivery catheter.
28. The delivery system of claim 1, wherein the seal assembly
includes a valve.
29. The delivery system of claim 10, wherein the introducer
catheter comprises a hemostasis seal assembly at a proximal end of
the introducer catheter.
Description
PRIORITY CLAIM TO RELATED PROVISIONAL APPLICATIONS
[0001] This present application is a continuation of U.S.
application Ser. No. 15/233,499, filed Aug. 10, 2016, which is a
divisional of U.S. application Ser. No. 13/777,745, filed Feb. 26,
2013, which claims priority benefit under 35 U.S.C. .sctn. 119(e)
from U.S. Provisional Application No. 61/640,862, filed May 1,
2012, entitled "Prosthetic Implant Delivery Device with Introducer
Catheter," and U.S. Provisional Application No. 61/707,744, filed
Sep. 28, 2012, entitled "Prosthetic Implant Delivery Device with
Introducer Catheter," which is incorporated by reference
herein.
BACKGROUND
Field
[0002] The present invention relates to medical methods and
devices, and, more specifically, to methods and devices for
percutaneously implanting a valve.
Description of the Related Art
[0003] The circulatory system is a closed loop bed of arterial and
venous vessels supplying oxygen and nutrients to the body
extremities through capillary beds. The driver of the system is the
heart providing correct pressures to the circulatory system and
regulating flow volumes as the body demands. Deoxygenated blood
enters heart first through the right atrium and is allowed to the
right ventricle through the tricuspid valve. Once in the right
ventricle, the heart delivers this blood through the pulmonary
valve and to the lungs for a gaseous exchange of oxygen. The
circulatory pressures carry this blood back to the heart via the
pulmonary veins and into the left atrium. Filling of the left
atrium occurs as the mitral valve opens allowing blood to be drawn
into the left ventricle for expulsion through the aortic valve and
on to the body extremities. When the heart fails to continuously
produce normal flow and pressures, a disease commonly referred to
as heart failure occurs.
[0004] The four valves of the heart (i.e., the tricuspid, the
pulmonary valve, the mitral valve and the aortic valve) function to
ensure that blood flows in only one direction through the heart.
The valves are made of thin flaps of tissue that open and close as
the heart contracts. Valvular heart disease is any disease process
involving one or more of the valves of the heart. For example,
disease and age can cause the tissue of a heart valve to thicken
and harden, which can case the valve to fail to open properly and
interfere with blood flow. This thickening process is often called
stenosis. A heart valve can also become weakened or stretched such
it no longer closes properly, which can cause blood leak back
through the valve. This leakage through the valve is often called
regurgitation. Problems with a heart valve can increase the amount
of work performed by the heart. The increase in work can cause the
heart muscle to enlarge or thicken to make up for the extra
workload.
[0005] The standard treatment for replacing an improperly working
valve is to replace it. Traditionally, valve replacement has been
accomplished via an open surgical procedure. More recently,
transcatheter valve replacement has been attempted via percutaneous
method such as a catheterization or delivery mechanism utilizing
the vasculature pathways. Open surgical procedures often include
the sewing of a new valve to the existing tissue structure for
securement. Access to these sites generally include a thoracotomy
or a sternotomy for the patient and include a great deal of
recovery time. Such open-heart surgical procedures can include
placing the patient on heart bypass to continue blood flow to vital
organs such as the brain during the surgery. Although open heart
surgical valve repair and replacement can successfully treat many
patients with valvular insufficiency, techniques currently in use
are attended by significant morbidity and mortality due to the
inherent invasiveness of open heart surgery.
[0006] According to recent estimates, more than 79,000 patients are
diagnosed with aortic and mitral valve disease in U.S. hospitals
each year. More than 49,000 mitral valve or aortic valve
replacement procedures are performed annually in the U.S., along
with a significant number of heart valve repair procedures. Since
surgical techniques are highly invasive, the need for a less
invasive method of heart valve replacement has long been
recognized. As noted above, transcatheter heart valve systems have
recently been developed in which heart valves are delivered through
the heart by an intravascular catheter. Such transcatheter heart
valves have the potential to reduce the anticipated mortality and
morbidity rates associated with traditional surgical valve surgery
particularly among patients of advanced age and/or with
comorbidities. However, a need remains for improvements over the
basic concept of transcatheter heart valve replacement. For
example, current transcatheter valve replacement can sometimes
result in vascular complications such as aortic dissection, access
site or access related vascular and/or distal embolization from a
vascular source. One method for reducing such complications is to
reduce ratio of the diameter of the delivery device for the heart
valve.
SUMMARY
[0007] One arrangement for delivering a cardiovascular prosthetic
implant using a minimally invasive procedure comprises an
introducer catheter having a proximal end and a distal end. A
delivery catheter extends through the introducer catheter. The
delivery catheter has a proximal end and a distal end extending
beyond the distal end of the introducer catheter. A hemostasis seal
assembly can be positioned a proximal end of the introducer
catheter. An outer diameter of the distal end of the delivery
catheter is greater than an inner diameter of the distal end of the
introducer catheter.
[0008] In the above mentioned arrangement, the delivery system can
include a cardiovascular prosthetic implant at the distal end of
the delivery catheter. The cardiovascular prosthetic implant can
include an inflatable cuff and a tissue valve.
[0009] In any of the above mentioned arrangements, the delivery
system can include at least one link between the catheter body and
the cardiovascular prosthetic implant.
[0010] In any of the above mentioned arrangements, the inner
diameter of the distal end of the introducer can be 16F or
less.
[0011] In any of the above mentioned arrangements, the introducer
catheter can include an elongated tapered tip.
[0012] In any of the above mentioned arrangements, the introducer
catheter can include a tapered tip that can transition from a first
enlarged length configuration to a second shorter
configuration.
[0013] In any of the above mentioned arrangements, the system can
include a long tip in a first configuration and a short tip in a
second configuration.
[0014] In any of the above mentioned arrangements, the system can
include a tip that has a straight configuration and a bent
configuration.
[0015] In another arrangement, a delivery system for delivering a
cardiovascular prosthetic implant using a minimally invasive
procedure includes an introducer catheter having a proximal end and
a distal end and a lumen extending from the proximal end to the
distal end of the introducer catheter. The introducer catheter has
an outer diameter defined by an outer surface of the introducer
catheter and an inner diameter defining the through lumen. A
delivery catheter extends through the introducer catheter. The
delivery catheter comprises a tubular body having a proximal end
and a distal end. The distal end includes a sheath jacket and stem
portion extending proximally from the sheath jacket. The sheath
jacket has an outer surface that defines an outer diameter of the
sheath jacket. The outer diameter of the sheath jacket is greater
than the inner diameter of the introduced catheter at the distal
end of the introducer catheter. The stem portion has an outer
surface that defines an outer diameter of the stem portion. The
outer diameter of the stem portion is smaller than the inner
diameter of the introducer catheter. A cardiovascular prosthetic
implant is positioned at least partially within the sheath
jacket.
[0016] In any of the above mentioned arrangements, the delivery
system can include a seal assembly at a proximal end of the
introducer catheter.
[0017] In any of the above mentioned arrangements, the delivery
system can include a cardiovascular prosthetic implant having an
inflatable cuff and a tissue valve.
[0018] In any of the above mentioned arrangements, the delivery
system can include at least one inflation lumen extending between
an inflatable cuff and the proximal end of the introducer catheter,
the inflation lumen extending through the delivery catheter.
[0019] In any of the above mentioned arrangements, the delivery
system can include at least one link between the catheter body and
a cardiovascular prosthetic implant.
[0020] In any of the above mentioned arrangements, the inner
diameter of the distal end of the introducer catheter is about
16F.
[0021] In any of the above mentioned arrangements, the delivery
system can include a tubing extending through the delivery catheter
and a cardiovascular prosthetic implant.
[0022] In any of the above mentioned arrangements, the delivery
system can include a distal tip coupled to a distal end of the
tubing, the distal tip having a maximum outside diameter that is
approximately the same as the outside diameter of a jacket
sheath.
[0023] In any of the above mentioned arrangements, the delivery
system can include a sheath jacket is coupled to a distal end of a
stem portion.
[0024] In another arrangement, a prosthetic implant is positioned
within a heart. The method comprises advancing an introducer
catheter positioned over a delivery catheter comprising a
prosthetic valve into a patient's vascular system, translumenally
advancing the prosthetic valve to a position proximate a native
valve of the heart; and deploying the prosthetic valve.
[0025] In the above mentioned method, the method can include
advancing the introducer catheter and delivery catheter over a
guidewire.
[0026] In any of the above mentioned methods, the method can
include inserting the introducer catheter into the femoral
artery.
[0027] In any of the above mentioned methods, the method can
include advancing the prosthetic valve through the aorta.
[0028] In any of the above mentioned methods, the method can
include inflating a portion of the prosthetic valve.
[0029] In any of the above mentioned methods, the method can
include inserting a distal end of the delivery catheter directly
into an access vessel.
[0030] In any of the above mentioned methods, the method can
include removing the delivery catheter and introducer catheter
together from the patient.
[0031] Further features and advantages of the present invention
will become apparent from the detailed description of preferred
embodiments which follows, when considered together with the
attached drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a cross-sectional schematic view of a heart and
its major blood vessels.
[0033] FIG. 2A is a partial cut-away view a left ventricle and
aortic with an prosthetic aortic valve implant according to one
embodiment.
[0034] FIG. 2B is a side view of the implant of FIG. 2A positioned
across a native aortic valve.
[0035] FIG. 3A is a front perspective view of the implant of FIG.
2B.
[0036] FIG. 3B is a front perspective view of an inflatable support
structure of the implant of FIG. 3A.
[0037] FIG. 3C is a cross-sectional side view of the implant of
FIG. 3A.
[0038] FIG. 3D is an enlarged cross-sectional view of an upper
portion of FIG. 3C.
[0039] FIG. 4 is a cross-sectional view of the connection port and
the inflation valve in the implant of FIG. 3B.
[0040] FIG. 5A is a side perspective view of a deployment catheter
with retracted implant.
[0041] FIG. 5B is a side perspective view of the deployment
catheter of FIG. 5A with the implant outside of the outer sheath
jacket.
[0042] FIG. 5C is a side perspective view of the position-and-fill
lumen (PFL), which is a component of the deployment catheter of
FIGS. 5A and 5B.
[0043] FIG. 6 is a cross-sectional view taken through line A-A of
FIG. 5B.
[0044] FIG. 7 is a side perspective view of a loading tool
base.
[0045] FIG. 8A is a side perspective view of an introduced catheter
deployment catheter with retracted implant.
[0046] FIG. 8B is a side perspective view of the introducer
catheter and deployment catheter of FIG. 8A with the implant
outside of the outer sheath jacket.
[0047] FIG. 8C is a side perspective view of the position-and-fill
lumen (PFL), which is a component of the deployment catheter of
FIGS. 8A and 8B.
[0048] FIG. 9 is a side view of the introducer catheter of FIGS.
8A-8C.
[0049] FIG. 10A is a side view of the deployment catheter of FIGS.
8A-8C.
[0050] FIG. 10B is an exploded view of a seal assembly.
[0051] FIG. 11A illustrates a step of partially deploying and
positioning an artificial valve implant.
[0052] FIG. 11B illustrates a second step of partially deploying
and positioning an artificial valve implant.
[0053] FIG. 11C illustrates a third step of partially deploying and
positioning an artificial valve implant.
[0054] FIG. 12A illustrates a step deploying, testing and
repositioning an artificial valve implant.
[0055] FIG. 12B illustrates a step deploying, testing and
repositioning an artificial valve implant.
[0056] FIG. 12C illustrates a step deploying, testing and
repositioning an artificial valve implant.
[0057] FIG. 12D illustrates a step deploying, testing and
repositioning an artificial valve implant.
[0058] FIG. 12E illustrates a step deploying, testing and
repositioning an artificial valve implant.
[0059] FIG. 13 illustrates a side view of another embodiment of a
deployment system.
[0060] FIG. 14 illustrates a side view of another embodiment of a
deployment system.
DETAILED DESCRIPTION
[0061] FIG. 1 is a schematic cross-sectional illustration of the
anatomical structure and major blood vessels of a heart 10.
Deoxygenated blood is delivered to the right atrium 12 of the heart
10 by the superior and inferior vena cava 14, 16. Blood in the
right atrium 12 is allowed into the right ventricle 18 through the
tricuspid valve 20. Once in the right ventricle 18, the heart 10
delivers this blood through the pulmonary valve 22 to the pulmonary
arteries 24 and to the lungs for a gaseous exchange of oxygen. The
circulatory pressures carry this blood back to the heart via the
pulmonary veins 26 and into the left atrium 28. Filling of the left
atrium 28 occurs as the mitral valve 30 opens allowing blood to be
drawn into the left ventricle 32 for expulsion through the aortic
valve 34 and on to the body extremities through the aorta 36. When
the heart 10 fails to continuously produce normal flow and
pressures, a disease commonly referred to as heart failure
occurs.
[0062] One cause of heart failure is failure or malfunction of one
or more of the valves of the heart 10. For example, the aortic
valve 34 can malfunction for several reasons. For example, the
aortic valve 34 may be abnormal from birth (e.g., bicuspid,
calcification, congenital aortic valve disease), or it could become
diseased with age (e.g., acquired aortic valve disease). In such
situations, it can be desirable to replace the abnormal or diseased
valve 34.
[0063] FIG. 2 is a schematic illustration of the left ventricle 32,
which delivers blood to the aorta 36 through the aortic valve 34.
The aorta 36 comprises (i) the ascending aorta 38, which arises
from the left ventricle 32 of the heart 10, (ii) the aortic arch
10, which arches from the ascending aorta 38 and (iii) the
descending aorta 42 which descends from the aortic arch 40 towards
the abdominal aorta (not shown). Also shown are the principal
branches of the aorta 14, which include the innomate artery 44 that
immediately divides into the right carotid artery (not shown) and
the right subclavian artery (not shown), the left carotid 46 and
the subclavian artery 48.
Inflatable Prosthetic Aortic Valve Implant
[0064] With continued reference to FIG. 2A, a cardiovascular
prosthetic implant 800 in accordance with one embodiment is shown
spanning the native abnormal or diseased aortic valve 34. The
implant 800 and various modified embodiments thereof will be
described in detail below. As will be explained in more detail
below, the implant 800 can be delivered minimally invasively using
an intravascular delivery catheter 900 or trans apical approach
with a trocar. Further details, additional embodiments of and/or
modifications of the implant or delivery system can be found in
U.S. Pat. Nos. 7,641,686, 8,012,201 and U.S. Publication Nos.
2007/0005133; 2009/0088836 and 2012/0016468, the entirety of these
patents and publications are hereby incorporated by reference
herein in their entirety.
[0065] The description below will be primarily in the context of
replacing or repairing an abnormal or diseased aortic valve 34.
However, various features and aspects of methods and structures
disclosed herein are applicable to replacing or repairing the
mitral 30, pulmonary 22 and/or tricuspid 20 valves of the heart 10
as those of skill in the art will appreciate in light of the
disclosure herein. In addition, those of skill in the art will also
recognize that various features and aspects of the methods and
structures disclosed herein can be used in other parts of the body
that include valves or can benefit from the addition of a valve,
such as, for example, the esophagus, stomach, ureter and/or
vesicle, biliary ducts, the lymphatic system and in the
intestines.
[0066] In addition, various components of the implant and its
delivery system will be described with reference to coordinate
system comprising "distal" and "proximal" directions. In this
application, distal and proximal directions refer to the deployment
system 900, which is used to deliver the implant 800 and advanced
through the aorta 36 in a direction opposite to the normal
direction of blood through the aorta 36. Thus, in general, distal
means closer to the heart while proximal means further from the
heart with respect to the circulatory system.
[0067] In some embodiments, the implant 800 can be a prosthetic
aortic valve implant. With reference to FIG. 2B in the illustrated
embodiment, the implant 800 can have a shape that can be viewed as
a tubular member or hyperboloid shape where a waist 805 excludes
the native valve 34 or vessel and proximally the proximal end 803
forms a hoop or ring to seal blood flow from re-entering the left
ventricle 32. Distally, the distal end 804 can also form a hoop or
ring to seal blood from forward flow through the outflow track.
Between the two ends 803 and 804, a valve 104 can be mounted to the
cuff or body 802 such that when inflated the implant 800 excludes
the native valve 34 or extends over the former location of the
native valve 34 and replaces its function. The distal end 804 can
have an appropriate size and shape so that it does not interfere
with the proper function of the mitral valve, but still secures the
valve adequately. For example, there can be a notch, recess or cut
out in the distal end 804 of the device to prevent mitral valve
interference. The proximal end 803 can be designed to sit in the
aortic root. In one arrangement, the proximal end 803 can be shaped
in such a way that it maintains good apposition with the wall of
the aortic root. This can prevent the device from migrating back
into the ventricle 32. In some embodiments, the implant 800 can be
configured such that it does not extend so high that it interferes
with the coronary arteries.
[0068] Any number of additional inflatable rings or struts can be
disposed between the proximal end 803 and distal end 804. The
distal end 804 of the implant 800 can be positioned within the left
ventricle 34 and can utilize the aortic root for axial
stabilization as it may have a larger diameter than the aortic
lumen. This arrangement may lessen the need for hooks, barbs or an
interference fit to the vessel wall. Since the implant 800 can be
placed without the aid of a dilatation balloon for radial
expansion, the aortic valve 34 and vessel may not have any duration
of obstruction and would provide the patient with more comfort and
the physician more time to properly place the device accurately.
Since in the illustrated arrangement, the implant 800 is not
utilizing a support member with a single placement option as a
plastically deformable or shaped memory metal stent does, the
implant 800 can be movable and or removable if desired. This could
be performed multiple times until the implant 800 is permanently
disconnected from the delivery catheter 900 as will be explained in
more detail below. In addition, as will be described below, the
implant 800 can include features, which allow the implant 800 to be
tested for proper function, sealing and sizing, before the catheter
900 is disconnected.
[0069] With reference to FIG. 3A, the implant 800 of the
illustrated embodiment generally comprises the inflatable cuff or
body 802, which is configured to support the valve 104 (see FIG.
2A) that is coupled to the cuff 802. In some embodiments, the valve
104 is a tissue valve. In some embodiments, the tissue valve has a
thickness equal to or greater than about 0.011 inches. In another
embodiment, the tissue valve has a thickness equal to or greater
than about 0.018 inches. As will be explained in more detail below,
the valve 104 can be configured to move in response to the
hemodynamic movement of the blood pumped by the heart 10 between an
"open" configuration where blood can throw the implant 800 in a
first direction and a "closed" configuration whereby blood is
prevented from back flowing through the valve 104 in a second
direction.
[0070] In the illustrated embodiment, the cuff 802 can comprise a
thin flexible tubular material such as a flexible fabric or thin
membrane with little dimensional integrity. As will be explained in
more detail below, the cuff 802 can be changed preferably, in situ,
to a support structure to which other components (e.g., the valve
104) of the implant 800 can be secured and where tissue ingrowth
can occur. Uninflated, the cuff 802 can be incapable of providing
support. In one embodiment, the cuff 802 comprises Dacron, PTFE,
ePTFE, TFE or polyester fabric as seen in conventional devices such
as surgical stented or stent less valves and annuloplasty rings.
The fabric thickness can range from about 0.002 inches to about
0.020 inches depending upon material selection and weave. Weave
density may also be adjusted from a very tight weave to prevent
blood from penetrating through the fabric to a looser weave to
allow tissue to grow and surround the fabric completely. In certain
embodiments, the fabric may have a linear mass density about 20
denier or lower.
[0071] With reference to FIGS. 3B-3D, in the illustrated
embodiment, the implant 800 can include an inflatable structure 813
that is formed by one or more inflation channels 808. The
inflatable channels 808 can be formed by a pair of distinct balloon
rings or toroids (807a and 807b) and struts 806. In the illustrated
embodiment, the implant 800 can include a proximal toroid 807a at
the proximal end 803 of the cuff 802 and a distal toroid 807b at
the distal end 804 of the cuff 802. The toroids 807 can be secured
to the cuff 802 in any of a variety of manners. With reference to
FIGS. 3C and 3D, in the illustrated embodiment, the toroids 807 can
be secured within folds 801 formed at the proximal end 803 and the
distal end 804 of the cuff 802. The folds 801, in turn, can be
secured by sutures or stitches 812. When inflated, the implant 800
can be supported in part by series of struts 806 surrounding the
cuff 802. In some embodiments, the struts 806 are configured so
that the portions on the cuff run substantially perpendicular to
the toroids. The struts can be sewn onto the cuff 802 or can be
enclosed in lumens made from the cuff material and swan onto the
cuff 802. The toroids 807 and the struts 806 together can form one
or more inflatable channels 808 that can be inflated by air, liquid
or inflation media.
[0072] With reference to FIG. 3B, the inflation channels can be
configured so that the cross-sectional profile of the implant 800
is reduced when it is compressed or in the retracted state. For
example, the inflation channels 808 can be arranged in a
step-function pattern. The inflation channels 808 can have three
connection ports 809 for coupling to the delivery catheter 900 via
position and fill lumen tubing (PFL) tubing 916 (see FIGS. 5A-5C).
In some embodiments, at least two of the connection ports 809 also
function as inflation ports, and inflation media, air or liquid can
be introduced into the inflation channel 808 through these ports.
The PFL tubing 916 can be connected to the connection ports 809 via
suitable connection mechanisms. In one embodiment, the connection
between the PFL tubing 916 and the connection port 809 is a screw
connection. In some embodiments, an inflation valve 810 is present
in the connection port 809 and can stop the inflation media, air or
liquid from escaping the inflation channels 808 after the PFL
tubing is disconnected. In some embodiments, the distal toroid 807b
and the proximal toroid 807a can be inflated independently. In some
embodiments, the distal toroid 807b can be inflated separately from
the struts 806 and the proximal toroid 807a. The separate inflation
can be useful during the positioning of the implant at the
implantation site. With reference to FIGS. 3C and 3D, the portion
of struts 806 can run parallel to the toroids 807 and can be
encapsulated within the folds 801 of the implant 800. This
arrangement may also aid in reducing the cross-sectional profile
when the implant is compressed or folded.
[0073] As mentioned above, the inflatable rings or toroids 807 and
struts 806 can form the inflatable structure 813, which, in turn,
defines the inflation channels 808. The inflation channels 808 can
receive inflation media to generally inflate the inflatable
structure 813. When inflated, the inflatable rings 807 and struts
806 can provide structural support to the inflatable implant 800
and/or help to secure the implant 800 thin the heart 10.
Uninflated, the implant 800 is a generally thin, flexible shapeless
assembly that is preferably incapable of support and is
advantageously able to take a small, reduced profile form in which
it can be percutaneously inserted into the body. As will be
explained in more detail below, in modified embodiments, the
inflatable structure 813 can comprise any of a variety of
configurations of inflation channels 808 that can be formed from
other inflatable members in addition to or in the alternative to
the inflatable rings 807 and struts 806 shown in FIGS. 3A and 3B.
In one embodiment, the valve has an expanded diameter that is
greater than or equal to 22 millimeters and a maximum compressed
diameter that is less than or equal to 6 millimeters (18F).
[0074] With particular reference to FIG. 3B, in the illustrated
embodiment, the distal ring 807b and struts 806 can be joined such
that the inflation channel 808 of the distal ring 807b is in fluid
communication with the inflation channel 808 of some of the struts
806. The inflation channel 808 of the proximal ring 807a can also
be in communication with the inflation channels 808 of the proximal
ring 807a and a few of the struts 806. In this manner, the
inflation channels of the (i) proximal ring 807a and a few struts
806 can be inflated independently from the (ii) distal ring 807b
and some struts. In some embodiments, the inflation channel of the
proximal ring 807a can be in communication with the inflation
channel of the struts 806, while the inflation channel of the
distal ring 807b is not in communication with the inflation channel
of the struts. As will be explained in more detail below, the two
groups of inflation channels 808 can be connected to independent
PFL tubing 916 to facilitate the independent inflation. It should
be appreciated that in modified embodiments the inflatable
structure can include less (i.e., one common inflation channel) or
more independent inflation channels. For example, in one
embodiment, the inflation channels of the proximal ring 807a,
struts 806 and distal ring 807b can all be in fluid communication
with each other such that they can be inflated from a single
inflation device. In another embodiment, the inflation channels of
the proximal ring 807a, struts 806 and distal ring 807b can all be
separated and therefore utilize three inflation devices.
[0075] With reference to FIG. 3B, in the illustrated embodiment,
each of the proximal ring 807a and the distal ring 807b can have a
cross-sectional diameter of about 0.090 inches. The struts can have
a cross-sectional diameter of about 0.060 inches. In some
embodiments, within the inflation channels 808 are also housed
valve systems that allow for pressurization without leakage or
passage of fluid in a single direction. In the illustrated
embodiment shown in FIG. 3B, two end valves or inflation valves 810
can reside at each end section of the inflation channels 808
adjacent to the connection ports 809. These end valves 810 are
utilized to fill and exchange fluids such as saline, contrast agent
and inflation media. The length of this inflation channel 808 can
vary depending upon the size of the implant 800 and the complexity
of the geometry. The inflation channel material can be blown using
heat and pressure from materials such as nylon, polyethylene,
Pebax, polypropylene or other common materials that will maintain
pressurization. The fluids that are introduced are used to create
the support structure, where without them, the implant 800 can be
an undefined fabric and tissue assembly. In one embodiment the
inflation channels 808 are first filled with saline and contrast
agent for radiopaque visualization under fluoroscopy. This can make
positioning the implant 800 at the implantation site easier. This
fluid is introduced from the proximal end of the catheter 900 with
the aid of an inflation device such as an endoflator or other
devices to pressurize fluid in a controlled manner. This fluid can
be transferred from the proximal end of the catheter 900 through
the PFL tubes 916 which are connected to the implant 800 at the end
of each inflation channel 808 at the connection port 809.
[0076] With reference to FIG. 3B, in the illustrated embodiment,
the inflation channel 808 can have an end valve 810 (i.e.,
inflation valve) at each end whereby they can be separated from the
PFL tubes 916 thus disconnecting the catheter from the implant.
This connection can be a screw or threaded connection, a colleting
system, an interference fit or other devices and methods of
reliable securement between the two components (i.e., the end valve
810 and the PFL tubes 916). In between the ends of the inflation
channel 808 can be an additional directional valve 811 to allow
fluid to pass in a single direction. This allows for the filling of
each end of the inflation channel 808 and displacement of fluid in
a single direction. Once the implant 808 is placed at the desired
position while inflated with saline and contrast agent, this fluid
can be displaced by an inflation media that can solidify or harden.
As the inflation media can be introduced from the proximal end of
the catheter 900, the fluid containing saline and contrast agent is
pushed out from one end of the inflation channel 808. Once the
inflation media completely displaces the first fluid, the PFL tubes
can then be disconnected from the implant 800 while the implant 800
remains inflated and pressurized. The pressure can be maintained in
the implant 800 by the integral valve (i.e., end valve 810) at each
end of the inflation channel 808. In the illustrated embodiment,
this end valve 810 can have a ball 303 and seat to allow for fluid
to pass when connected and seal when disconnected. In some case the
implant 800 has three or more connection ports 809, but only two
have inflation valves 810 attached. The connection port without the
end valve 810 can use the same attachment device such as a screw or
threaded element. Since, the illustrated embodiment, this
connection port is not used for communication with the support
structure 813 and its filling, no inflation valve 810 is necessary.
In other embodiments, all three connection ports 809 can have
inflation valves 810 for introducing fluids or inflation media.
[0077] With reference to FIG. 4, the end valve system 810 can
comprise a tubular section 312 with a soft seal 304 and spherical
ball 303 to create a sealing mechanism 313. The tubular section 312
in one embodiment is about 0.5 cm to about 2 cm in length and has
an outer diameter of about 0.010 inches to about 0.090 inches with
a wall thickness of about 0.005 inches to about 0.040 inches. The
material can include a host of polymers such as nylon,
polyethylene, Pebax, polypropylene or other common materials such
as stainless steel, Nitinol or other metallic materials used in
medical devices. The soft seal material can be introduced as a
liquid silicone or other material where a curing occurs thus
allowing for a through hole to be constructed by coring or blanking
a central lumen through the seal material. The soft seal 304 can be
adhered to the inner diameter of the wall of the tubular member 312
with a through hole for fluid flow. The spherical ball 303 can move
within the inner diameter of the tubular member 312 where it seats
at one end sealing pressure within the inflation channels and is
moved the other direction with the introduction of the PFL tube 916
but not allowed to migrate too far as a stop ring or ball stopper
305 retains the spherical ball 303 from moving into the inflation
channel 808. As the PFL tube 916 is screwed into the connection
port 809, the spherical ball 303 is moved into an open position to
allow for fluid communication between the inflation channel 808 and
the PFL tube 916. When disconnected, the ball 303 ca move against
the soft seal 304 and halt any fluid communication external to the
inflation channel 808 leaving the implant 800 pressurized.
Additional embodiments can utilize a spring mechanism to return the
ball to a sealed position and other shapes of sealing devices may
be used rather than a spherical ball. A duck-bill style sealing
mechanism or flap valve can also be used to halt fluid leakage and
provide a closed system to the implant. Additional end valve
systems have been described in U.S. Patent Publication No.
2009/0088836 to Bishop et al., which is thereby incorporated by
reference herein.
[0078] The implant 800 of the illustrated embodiment ca allow
delivery a prosthetic valve via catheterization in a lower profile
and a safer manner than currently available. When the implant 800
is delivered to the site via a delivery catheter 900, the implant
800 is a thin, generally shapeless assembly in need of structure
and definition. At the implantation site, the inflation media
(e.g., a fluid or gas) can be added via PFL tubes of the delivery
catheter 900 to the inflation channels 808 providing structure and
definition to the implant 800. The inflation media therefore can
comprise part of the support structure for implant 800 after it is
inflated. The inflation media that is inserted into the inflation
channels 808 can be pressurized and/or can solidify in situ to
provide structure to the implant 800. Additional details and
embodiments of the implant 800, can be found in U.S. Pat. No.
5,554,185 to Block and U.S. Patent Publication No. 2006/0088836 to
Bishop et al., the disclosures of which are expressly incorporated
by reference in their entirety herein.
[0079] The cuff 802 can be made from many different materials such
as Dacron, TFE, PTFE, ePTFE, woven metal fabrics, braided
structures, or other generally accepted implantable materials.
These materials may also be cast, extruded, or seamed together
using heat, direct or indirect, sintering techniques, laser energy
sources, ultrasound techniques, molding or thermoforming
technologies. Since the inflation channels 808 generally surrounds
the cuff 802, and the inflation channels 808 can be formed by
separate members (e.g., balloons and struts), the attachment or
encapsulation of these inflation channels 808 can be in intimate
contact with the cuff material. In some embodiments, the inflation
channels 808 are encapsulated in the folds 801 or lumens made from
the cuff material sewn to the cuff 802. These inflation channels
808 can also be formed by sealing the cuff material to create an
integral lumen from the cuff 802 itself. For example, by adding a
material such as a silicone layer to a porous material such as
Dacron, the fabric can resist fluid penetration or hold pressures
if sealed. Materials can also be added to the sheet or cylinder
material to create a fluid-tight barrier.
[0080] Various shapes of the cuff 802 can be manufactured to best
fit anatomical variations from person to person. As described
above, these may include a simple cylinder, a hyperboloid, a device
with a larger diameter in its mid portion and a smaller diameter at
one or both ends, a funnel type configuration or other conforming
shape to native anatomies. The shape of the implant 800 is
preferably contoured to engage a feature of the native anatomy in
such a way as to prevent the migration of the device in a proximal
or distal direction. In one embodiment the feature that the device
engages is the aortic root or aortic bulb 34 (see e.g., FIG. 2A),
or the sinuses of the coronary arteries. In another embodiment the
feature that the device engages is the native valve annulus, the
native valve or a portion of the native valve. In certain
embodiments, the feature that the implant 800 engages to prevent
migration has a diameter difference between 1% and 10%. In another
embodiment, the feature that the implant 800 engages to prevent
migration the diameter difference is between 5% and 40%. In certain
embodiments the diameter difference is defined by the free shape of
the implant 800. In another embodiment the diameter difference
prevents migration in only one direction. In another embodiment,
the diameter difference prevents migration in two directions, for
example proximal and distal or retrograde and antigrade. Similar to
surgical valves, the implant 800 will vary in diameter ranging from
about 14 mm to about 30 mm and have a height ranging from about 10
mm to about 30 mm in the portion of the implant 800 where the
leaflets of the valve 104 are mounted. Portions of the implant 800
intended for placement in the aortic root can have larger diameters
preferably ranging from about 20 mm to about 45 mm. In some
embodiment, the implant 800 can have an outside diameter greater
than about 22 mm when fully inflated.
[0081] In certain embodiments, the cuffs, inflated structure can
conform (at least partially) to the anatomy of the patient as the
implant 800 is inflated. Such an arrangement may provide a better
seal between the patient's anatomy and the implant 800.
[0082] Different diameters of prosthetic valves may be needed to
replace native valves of various sizes. For different locations in
the anatomy, different lengths of prosthetic valves or anchoring
devices will also be required. For example a valve designed to
replace the native aortic valve needs to have a relatively short
length because of the location of the coronary artery ostium (left
and right arteries). A valve designed to replace or supplement a
pulmonary valve could have significantly greater length because the
anatomy of the pulmonary artery allows for additional length.
Different anchoring mechanisms that may be useful for anchoring the
implant 800 have been described in U.S. Patent Publication No.
2009/0088836 to Bishop et al.
[0083] In the embodiments described herein, the inflation channels
808 can be configured such that they are of round, oval, square,
rectangular or parabolic shape in cross section. Round cross
sections may vary from about 0.020-about 0.100 inches in diameter
with wall thicknesses ranging from about 0.0005-about 0.010 inches.
Oval cross sections may have an aspect ratio of two or three to one
depending upon the desired cuff thickness and strength desired. In
embodiments in which the inflation channels 808 are formed by
balloons, these channels 808 can be constructed from conventional
balloon materials such as nylon, polyethylene, PEEK, silicone or
other generally accepted medical device material
[0084] In some embodiments, portions of the cuff or body 802 can be
radio-opaque to aid in visualizing the position and orientation of
the implant 800. Markers made from platinum gold or tantalum or
other appropriate materials may be used. These may be used to
identify critical areas of the valve that must be positioned
appropriately, for example the valve commissures may need to be
positioned appropriately relative to the coronary arteries for an
aortic valve. Additionally during the procedure it may be
advantageous to catheterize the coronary arteries using
radio-opaque tipped guide catheters so that the ostium can be
visualized. Special catheters could be developed with increased
radio-opacity or larger than standard perfusion holes. The
catheters could also have a reduced diameter in their proximal
section allowing them to be introduced with the valve deployment
catheter.
[0085] As mentioned above, during delivery, the body 802 can be
limp and flexible providing a compact shape to fit inside a
delivery sheath. The body 802 is therefore preferably made form a
thin, flexible material that is biocompatible and may aid in tissue
growth at the interface with the native tissue. A few examples of
material may be Dacron, ePTFE, PTFE, TFE, woven material such as
stainless steel, platinum, MP35N, polyester or other implantable
metal or polymer. As mentioned above with reference to FIG. 2A, the
body 802 may have a tubular or hyperboloid shape to allow for the
native valve to be excluded beneath the wall of the cuff 802.
Within this cuff 802 the inflation channels 808 can be connected to
a catheter lumen for the delivery of an inflation media to define
and add structure to the implant 800. The valve 104, which is
configured such that a fluid, such as blood, may be allowed to flow
in a single direction or limit flow in one or both directions, is
positioned within the cuff 802. The attachment method of the valve
104 to the cuff 802 can be by conventional sewing, gluing, welding,
interference or other devices and methods generally accepted by
industry.
[0086] In one embodiment, the cuff 802 would have a diameter of
between about 15 mm and about 30 mm and a length of between about 6
mm and about 70 mm. The wall thickness would have an ideal range
from about 0.01 mm to about 2 mm. As described above, the cuff 802
may gain longitudinal support in situ from members formed by
inflation channels or formed by polymer or solid structural
elements providing axial separation. The inner diameter of the cuff
802 may have a fixed dimension providing a constant size for valve
attachment and a predictable valve open and closure function.
Portions of the outer surface of the cuff 802 may optionally be
compliant and allow the implant 800 to achieve interference fit
with the native anatomy.
[0087] The implant 800 can have various overall shapes (e.g., an
hourglass shape to hold the device in position around the valve
annulus, or the device may have a different shape to hold the
device in position in another portion of the native anatomy, such
as the aortic root). Regardless of the overall shape of the implant
800, the inflatable channels 808 can be located near the proximal
and distal ends 803, 804 of the implant 800, preferably forming a
configuration that approximates a ring or toroid 807. These
channels may be connected by intermediate channels designed to
serve any combination of three functions: (i) provide support to
the tissue excluded by the implant 800, (ii) provide axial and
radial strength and stiffness to the 800, and/or (iii) to provide
support for the valve 104. The specific design characteristics or
orientation of the inflatable structure 813 can be optimized to
better serve each function. For example if an inflatable channel
808 were designed to add axial strength to the relevant section of
the device, the channels 808 would ideally be oriented in a
substantially axial direction.
[0088] The cuff 802 and inflation channels 808 of the implant 800
can be manufactured in a variety of ways. In one embodiment the
cuff 802 is manufactured from a fabric, similar to those fabrics
typically used in endovascular grafts or for the cuffs of
surgically implanted prosthetic heart valves. The fabric is
preferably woven into a tubular shape for some portions of the cuff
802. The fabric may also be woven into sheets. In one embodiment,
the yarn used to manufacture the fabric is preferably a twisted
yarn, but monofilament or braided yarns may also be used. The
useful range of yarn diameters is from approximately 0.0005 of an
inch in diameter to approximately 0.005 of an inch in diameter.
Depending on how tight the weave is made. Preferably, the fabric is
woven with between about 50 and about 500 yarns per inch. In one
embodiment, a fabric tube is woven with a 18 mm diameter with 200
yarns per inch or picks per inch. Each yarn is made of 20 filaments
of a PET material. The final thickness of this woven fabric tube is
0.005 inches for the single wall of the tube. Depending on the
desired profile of the implant 800 and the desired permeability of
the fabric to blood or other fluids different weaves may be used.
Any biocompatible material may be used to make the yarn, some
embodiments include nylon and PET. Other materials or other
combinations of materials are possible, including Teflon,
fluoropolymers, polyimide, metals such as stainless steel,
titanium, Nitinol, other shape memory alloys, alloys comprised
primarily of a combinations of cobalt, chromium, nickel, and
molybdenum. Fibers may be added to the yarn to increases strength
or radiopacity, or to deliver a pharmaceutical agent. The fabric
tube may also be manufactured by a braiding process.
[0089] The fabric can be stitched, sutured, sealed, melted, glued
or bonded together to form the desired shape of the implant 800.
The preferred method for attaching portions of the fabric together
is stitching. The preferred embodiment uses a polypropylene
monofilament suture material, with a diameter of approximately
0.005 of an inch. The suture material may range from about 0.001 to
about 0.010 inches in diameter. Larger suture materials may be used
at higher stress locations such as where the valve commissures
attach to the cuff. The suture material may be of any acceptable
implant grade material. Preferably a biocompatible suture material
is used such as polypropylene. Nylon and polyethylene are also
commonly used suture materials. Other materials or other
combinations of materials are possible, including Teflon,
fluoropolymers, polyimides, metals such as stainless steel,
titanium, Kevlar, Nitinol, other shape memory alloys, alloys
comprised primarily of a combinations of cobalt, chromium, nickel,
and molybdenum such as MP35N. Preferably the sutures are a
monofilament design. Multi strand braided or twisted suture
materials also may be used. Many suture and stitching patterns are
possible and have been described in various texts. The preferred
stitching method is using some type of lock stitch, of a design
such that if the suture breaks in a portion of its length the
entire running length of the suture will resist unraveling. And the
suture will still generally perform its function of holding the
layers of fabric together.
[0090] In some embodiments, the implant 800 is not provided with
separate balloons, instead the fabric of the cuff 802 itself can
form the inflation channels 808. For example, in one embodiment two
fabric tubes of a diameter similar to the desired final diameter of
the implant 800 are place coaxial to each other. The two fabric
tubes are stitched, fused, glued or otherwise coupled together in a
pattern of channels 808 that is suitable for creating the geometry
of the inflatable structure 813. In some embodiments, the fabric
tubes are sewn together in a pattern so that the proximal and
distal ends of the fabric tubes form an annular ring or toroid 807.
In some embodiments, the middle section of the implant 800 contains
one or more inflation channels shaped in a step-function pattern.
In some embodiments, the fabric tubes are sewn together at the
middle section of the implant to form inflation channels 808 that
are perpendicular to the toroids 807 at the end sections of the
implant 800. Methods for fabricating the implant 800 have been
described in U.S. Patent Publication No. 2006/0088836 to Bishop et
al.
[0091] In the illustrated embodiment of FIGS. 3A and 3B, the struts
806 are arranged such that there is no radial overlap with the
distal and proximal rings 807a, 807b. That is, in the illustrated
embodiment, the struts 808 do not increase the radial thickness of
the inflation structure because there is no radial overlap between
the distal and proximal rings and the channels so that the channels
lie within the radial thickness envelop defined by the distal and
proximal rings 807a, 807b. In another embodiment, the struts 808
can be wider in the radial direction than the distal and proximal
rings 807a, 807b such that the distal and proximal rings 807a, 807b
lie within a radial thickness envelop defined by the struts
806.
[0092] In one embodiment, the valve 800 can be delivered through a
deployment catheter with an 18 F or smaller outer diameter and when
fully inflated has an effective orifice area of at least about 1.0
square cm; and in another embodiment at least about 1.3 square cm
and in another embodiment about 1.5 square cm. In one embodiment,
the valve 800 has a minimum cross-sectional flow area of at least
about 1.75 square cm.
Leaflet Subassembly
[0093] With reference back to the embodiments of FIG. 2A, the valve
104 preferably is a tissue-type heart valve that includes a
dimensionally stable, pre-aligned tissue leaflet subassembly.
Pursuant to this construction, an exemplary tissue valve 104 can
include a plurality of tissue leaflets that are templated and
attached together at their tips to form a dimensionally stable and
dimensionally consistent coapting leaflet subassembly. Then, in
what can be a single process, each of the leaflets of the
subassembly can be aligned with and individually sewn to the cuff
802, from the tip of one commissure uniformly, around the leaflet
cusp perimeter, to the tip of an adjacent commissure. As a result,
the sewed sutures act like similarly aligned staples, all of which
equally take the loading force acting along the entire cusp of each
of the pre-aligned, coapting leaflets. Once inflated, the cuff 802
can support the commissures with the inflation media and its
respective pressure which will solidify and create a system similar
to a stent structure. The resulting implant 800 thereby formed can
reduce stress and potential fatigue at the leaflet suture interface
by distributing stress evenly over the entire leaflet cusp from
commissure to commissure. In some embodiments, the tissue valve is
coupled to the inflatable cuff 802 by attaching to the fabric of
the cuff only.
[0094] In one embodiment, the tissue leaflets are not coupled to
each other but are instead individually attached to the cuff
802.
[0095] A number of additional advantages can result from the use of
the implant 800 and the cuff 802 construction utilized therein. For
example, for each key area of the cuff 802, the flexibility can be
optimized or customized. If desired, the coapting tissue leaflet
commissures can be made more or less flexible to allow for more or
less deflection to relieve stresses on the tissue at closing or to
fine tune the operation of the valve. Similarly, the base radial
stiffness of the overall implant structure can be increased or
decreased by pressure or inflation media to preserve the roundness
and shape of the implant 800.
[0096] Attachment of the valve 104 to the cuff 802 can be completed
in any number of conventional methods including sewing, ring or
sleeve attachments, gluing, welding, interference fits, bonding
through mechanical devices and methods such as pinching between
members. An example of these methods are described in Published
Applications from Huynh et al (06/102944) or Lafrance et al
(2003/0027332) or U.S. Pat. No. 6,409,759 to Peredo, which are
hereby incorporated by reference herein. These methods are
generally know and accepted in the valve device industry. The
valve, whether it is tissue, engineered tissue, mechanical or
polymer, may be attached before packaging or in the hospital just
before implantation. Some tissue valves are native valves such as
pig, horse, cow or native human valves. Most of which are suspended
in a fixing solution such as Glutaraldehyde.
[0097] In some embodiments, heart valve prostheses can be
constructed with flexible tissue leaflets or polymer leaflets.
Prosthetic tissue heart valves can be derived from, for example,
porcine heart valves or manufactured from other biological
material, such as bovine or equine pericardium. Biological
materials in prosthetic heart valves generally have profile and
surface characteristics that provide laminar, nonturbulent blood
flow. Therefore, intravascular clotting is less likely to occur
than with mechanical heart valve prostheses.
[0098] Natural tissue valves can be derived from an animal species,
typically mammalian, such as human, bovine, porcine canine, seal or
kangaroo. These tissues can be obtained from, for example, heart
valves, aortic roots, aortic walls, aortic leaflets, pericardial
tissue such as pericardial patches, bypass grafts, blood vessels,
human umbilical tissue and the like. These natural tissues are
typically soft tissues, and generally include collagen containing
material. The tissue can be living tissue, decellularized tissue or
recellularized tissue. Tissue can be fixed by crosslinking.
Fixation provides mechanical stabilization, for example by
preventing enzymatic degradation of the tissue. Glutaraldehyde or
formaldehyde is typically used for fixation, but other fixatives
can be used, such as other difunctional aldehydes, epoxides,
genipin and derivatives thereof. Tissue can be used in either
crosslinked or uncrosslinked form, depending on the type of tissue,
use and other factors. Generally, if xenograft tissue is used, the
tissue is crosslinked and/or decellularized. Additional description
of tissue valves can be found in U.S. Patent Publication No.
2009/008836 to Bishop et al.
Inflation Media
[0099] The inflatable structure 813 can be inflated using any of a
variety of inflation media, depending upon the desired performance.
In general, the inflation media can include a liquid such water or
an aqueous based solution, a gas such as CO.sub.2, or a hardenable
media which may be introduced into the inflation channels 808 at a
first, relatively low viscosity and converted to a second,
relatively high viscosity. Viscosity enhancement may be
accomplished through any of a variety of known UV initiated or
catalyst initiated polymerization reactions, or other chemical
systems known in the art. The end point of the viscosity enhancing
process may result in a hardness anywhere from a gel to a rigid
structure, depending upon the desired performance and
durability.
[0100] Useful inflation media generally include those formed by the
mixing of multiple components and that have a cure time ranging
from a tens of minutes to about one hour, preferably from about
twenty minutes to about one hour. Such a material may be
biocompatible, exhibit long-term stability (preferably on the order
of at least ten years in vivo), pose as little an embolic risk as
possible, and exhibit adequate mechanical properties, both pre and
post-cure, suitable for service in the cuff in vivo. For instance,
such a material should have a relatively low viscosity before
solidification or curing to facilitate the cuff and channel fill
process. A desirable post-cure elastic modulus of such an inflation
medium is from about 50 to about 400 psi--balancing the need for
the filled body to form an adequate seal in vivo while maintaining
clinically relevant kink resistance of the cuff. The inflation
media ideally should be radiopaque, both acute and chronic,
although this is not absolutely necessary.
[0101] One preferred family of hardenable inflation media are two
part epoxies. The first part is an epoxy resin blend comprising a
first aromatic diepoxy compound and a second aliphatic diepoxy
compound. The first aromatic diepoxy compound provides good
mechanical and chemical stability in an aqueous environment while
being soluble in aqueous solution when combined with suitable
aliphatic epoxies. In some embodiments, the first aromatic diepoxy
compound comprises at least one N,N-diglycidylaniline group or
segment. In some embodiments, the first aromatic diepoxy compound
are optionally substituted N,N-diglycidylaniline. The substitutent
may be glycidyloxy or N,N-diglycidylanilinyl-methyl. Non-limiting
examples of the first aromatic diepoxy compound are
N,N-diglycidylaniline, N,N-diclycidyl-4-glycidyloxyaniline (DGO)
and 4,4'-methylene-bis(N,N-diglycidylaniline) (MBD), etc.
[0102] The second aliphatic diepoxy compound provides low viscosity
and good solubility in an aqueous solution. In some embodiments,
the second aliphatic diepoxy compound may be 1,3-butadiene
diepoxide, glycidyl ether or C.sub.1-5 alkane diols of glycidyl
ether. Non-limiting examples of the second aliphatic diepoxy
compounds are 1,3-butadiene diepoxide, butanediol diglycidyl ether
(BDGE), 1,2-ethanediol diglycidyl ether, glycidyl ether, etc.
[0103] In some embodiments, additional third compound may be added
to the first part epoxy resin blend for improving mechanical
properties and chemical resistance. In some embodiments, the
additional third compound may be an aromatic epoxy other than the
one containing N,N-diglycidylanaline. However, the solubility of
the epoxy resin blend can also decrease and the viscosity can
increase as the concentration of the additional aromatic epoxies
increases. The preferred third compound may be
tris(4-hydroxyphenyl)methane triglycidyl ether (THTGE), bisphenol A
diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), or
resorcinol diglycidyl ether (RDGE).
[0104] In some embodiments, the additional third compound may be a
cycloaliphatic epoxy compound, preferably more soluble than the
first aromatic diepoxy compound. It can increase the mechanical
properties and chemical resistance to a lesser extent than the
aromatic epoxy described above, but it will not decrease the
solubility as much. Non-limiting examples of such cycloaliphatic
epoxy are 1,4-cyclohexanedimethanol diclycidyl ether and
cyclohexene oxide diglycidyl 1,2-cyclohexanedicarboxylate.
Similarly, in some embodiments, aliphatic epoxy with 3 or more
glycidyl ether groups, such as polyglycidyl ether, may be added as
the additional third compound for the same reason. Polyglycidyl
ether may increase cross linking and thus enhance the mechanical
properties.
[0105] In general, the solubility of the epoxy resin blend
decreases and the viscosity increases as the concentration of the
first aromatic diepoxy compound increases. In addition, the
mechanical properties and chemical resistance may be reduced as the
concentration of the aliphatic diepoxy compound goes up in the
epoxy resin blend. By adjusting the ratio of the first aromatic
dipoxy compound and the second aliphatic diepoxy compound, a person
skilled in the art can control the desired properties of the epoxy
resin blend and the hardened media. Adding the third compound in
some embodiments may allow further tailoring of the epoxy resin
properties.
[0106] The second part of the hardenable inflation media comprises
a hardener comprising at least one cycloaliphatic amine. It
provides good combination of reactivity, mechanical properties and
chemical resistance. The cycloaliphatic amine may include, but not
limited to, isophorone diamine (IPDA), 1,3-bisaminocyclohexame
(1,3-BAC), diamino cyclohexane (DACH), n-aminoethylpiperazine (AEP)
or n-aminopropylpiperazine (APP).
[0107] In some embodiments, an aliphatic amine may be added into
the second part to increase reaction rate, but may decrease
mechanical properties and chemical resistance. The preferred
aliphatic amine has the structural formula (I):
##STR00001##
wherein each R is independently selected from branched or linear
chains of C.sub.2-5 alkyl, preferably C.sub.2 alkyl. The term
"alkyl" as used herein refers to a radical of a fully saturated
hydrocarbon, including, but not limited to, methyl, ethyl,
n-propyl, isopropyl (or i-propyl), n-butyl, isobutyl, tert-butyl
(or t-butyl), n-hexyl, and the like. For example, the term "alkyl"
as used herein includes radicals of fully saturated hydrocarbons
defined by the following general formula C.sub.nH.sub.2n+2. In some
embodiments, the aliphatic amine may include, but not limited to,
tetraehtylenepentamine (TEPA), diethylene triamine and triethylene
tetraamine. In some embodiments, the hardener may further comprise
at least one radio-opaque compound, such as iodo benzoic acids.
[0108] Additional details of hardenable inflation media are
described in co-pending application titled "Inflation Media
Formulation" application Ser. No. 13/110,780, filed May 18, 2011,
the entirety of which is hereby incorporated herein by reference.
Other suitable inflation media are also described in U.S. patent
application Ser. No. 09/496,231 to Hubbell et al., filed Feb. 1,
2000, entitled "Biomaterials Formed by Nucleophilic Addition
Reaction to Conjugated Unsaturated Groups" and U.S. Pat. No.
6,958,212 to Hubbell et al. The entireties of each of these patents
are hereby incorporated herein by reference.
[0109] Below is listed one particular two-component medium. This
medium comprises:
First Part--Epoxy Resin Blend
[0110] (1) N,N-Diglycidyl-4-glycidyloxyaniline (DGO), present in a
proportion ranging from about 10 to about 70 weight percent;
specifically in a proportion of about 50 weight percent,
[0111] (2) Butanediol diglycidyl ether (BDGE) present in a
proportion ranging from about 30 to about 75 weight percent;
specifically in a proportion of about 50 weight percent, and
optionally
[0112] (3) 1,4-Cyclohexanedimethanol diglycidyl ether, present in a
proportion ranging from about 0 to about 50 weight percent.
Second Part--Amine Hardener
[0113] (1) Isophorone diamine (IPDA), present in a proportion
ranging from about 75 to about 100 weight percent, and
optionally
[0114] (2) Diethylene triamine (DETA), present in a proportion
ranging from about 0 to about 25 weight percent.
[0115] The mixed uncured inflation media preferably has a viscosity
less than 2000 cps. In one embodiment the epoxy based inflation
media has a viscosity of 100-200 cps. In another embodiment the
inflation media has a viscosity less than 1000 cps. In some
embodiments, the epoxy mixture has an initial viscosity of less
than about 50 cps, or less than about 30 cps after mixing. In some
embodiments, the average viscosity during the first 10 minutes
following mixing the two components of the inflation media is about
50 cps to about 60 cps. The low viscosity ensures that the
inflation media can be delivered through the inflation lumen of a
deployment catheter with small diameter, such as an 18 French
catheter
[0116] In some embodiments, the balloon or inflation channel may be
connected to the catheter on both ends. This allows the balloon to
be pre-inflated with a non-solidifying material such as a gas or
liquid. If a gas is chosen, CO.sub.2 or helium are the likely
choices; these gasses are used to inflate intra-aortic balloon
pumps. Preferably the pre-inflation media is radio-opaque so that
the balloon position can be determined by angiography. Contrast
media typically used in interventional cardiology could be used to
add sufficient radio-opacity to most liquid pre-inflation media.
When it is desired to make the implant permanent and exchange the
pre-inflation media for the permanent inflation media, the
permanent inflation media is injected into the inflation channel
through a first catheter connection. In some embodiments, the
permanent inflation media is capable of solidifying into a
semi-solid, gel or solid state. As the permanent inflation media is
introduced into the inflatable structure, the pre-inflation media
is expelled out from a second catheter connection. The catheter
connections are positioned in such a way that substantially all of
the pre-inflation media is expelled as the permanent inflation
media is introduced. In one embodiment an intermediate inflation
media is used to prevent entrapment of pre-inflation media in the
permanent inflation media. In one embodiment the intermediate
inflation media is a gas and the pre-inflation media is a liquid.
In another embodiment the intermediate inflation media or
pre-inflation media functions as a primer to aid the permanent
inflation media to bond to the inner surface of the inflation
channel. In another embodiment the pre-inflation media or the
intermediate inflation media serves as a release agent to prevent
the permanent inflation media from bonding to the inner surface of
the inflation channel.
The permanent inflation media may have a different radiopacity than
the pre-inflation media. A device that is excessively radiopaque
tends to obscure other nearby features under angiography. During
the pre-inflation step it may be desirable to visualize the
inflation channel clearly, so a very radiopaque inflation media may
be chosen. After the device is inflated with the permanent
inflation media a less radiopaque inflation media may be preferred.
The feature of lesser radiopacity is beneficial for visualization
of proper valve function as contrast media is injected into the
ventricle or the aorta.
[0117] Low Crossing Profile Delivery System
[0118] FIGS. 5A-5B illustrate an embodiment of a low crossing
profile delivery catheter 900 that can be used to deliver the
implant 800. In general, the delivery system comprises a delivery
catheter 900, and the delivery catheter 900 can comprise an
elongate, flexible catheter body having a proximal end and a distal
end. In some embodiments, the catheter body has a maximum outer
diameter of about 18 French or less particularly at the distal
portion of the catheter body (i.e. the deployment portion). In some
embodiments, the delivery catheter also comprises a cardiovascular
prosthetic implant 800 (e.g., configured as described above) at the
distal end of the catheter body. While using a cardiovascular
prosthetic implant 800 as described above has certain advantages,
in modified embodiments, certain features of the delivery catheter
and delivery system described herein can also be used with a
prosthetic implant that utilizes a stent or other support structure
and/or does not utilize an inflation media.
[0119] As described herein, certain features of the implant 800 and
delivery catheter 900 are particularly advantageous for
facilitating delivering of cardiovascular prosthetic implant 800
within a catheter body having outer diameter of about 18 French or
less while still maintaining a tissue valve thickness equal to or
greater than about 0.011 inches and/or having an effective orifice
area equal to or greater than about 1 cm squared, or in another
embodiment, 1.3 cm squared or in another embodiment 1.5 cm squared.
In such embodiments, the implant 800 can also have an expanded
maximum diameter that is greater than or equal to about 22 mm. In
some embodiments, at least one link exists between the catheter
body and the implant 800. In some embodiments, the at least one
link is the PFL tubing. In one embodiment, the delivery system is
compatible with 0.035'' or 0.038'' guidewire.
[0120] In general, the delivery catheter 900 can be constructed
with extruded tubing using well known techniques in the industry.
In some embodiments, the catheter 900 can incorporates braided or
coiled wires and or ribbons into the tubing for providing stiffness
and rotational torqueability. Stiffening wires may number between 1
and 64. In some embodiments, a braided configuration is used that
comprises between 8 and 32 wires or ribbon. If wires are used in
other embodiments, the diameter can range from about 0.0005 inches
to about 0.0070 inches. If a ribbon is used, the thickness is
preferably less than the width, and ribbon thicknesses may range
from about 0.0005 inches to about 0.0070 inches while the widths
may range from about 0.0010 inches to about 0.0100 inches. In
another embodiment, a coil is used as a stiffening member. The coil
can comprise between 1 and 8 wires or ribbons that are wrapped
around the circumference of the tube and embedded into the tube.
The wires may be wound so that they are parallel to one another and
in the curved plane of the surface of the tube, or multiple wires
may be wrapped in opposing directions in separate layers. The
dimensions of the wires or ribbons used for a coil can be similar
to the dimensions used for a braid.
[0121] With reference to FIGS. 5A and 5B, the catheter 900 can
comprise an outer tubular member 901 having a proximal end 902 and
a distal end 903, and an inner tubular member 904 also having a
proximal end 905 and a distal end 906. The inner tubular member 904
can extend generally through the outer tubular member 901, such
that the proximal and distal ends 902, 903 of the inner tubular
member 904 extend generally past the proximal end 902 and distal
end 903 of the outer tubular member 901. The distal end 903 of the
outer tubular member 901 can comprise a sheath jacket 912 and a
stem region 917 that extends proximally from the sheath jacket 912.
In some embodiments, the sheath jacket 912 may comprise KYNAR
tubing. The sheath jacket 912 can house the implant 800 in a
retracted state for delivery to the implantation site. In some
embodiments, the sheath jacket 912 is capable of transmitting at
least a portion of light in the visible spectrum. This allows the
orientation of the implant 800 to be visualized within the catheter
900. In some embodiments, an outer sheath marking band 913 may be
located at the distal end 903 of the outer tubular member 901.
[0122] In one embodiment, the sheath jacket 912 can have a larger
outside diameter than the adjacent or proximate region of the stem
region 917 of the tubular member 901. In such embodiments, the
sheath jacket 917 and the stem region 917 can comprise separate
tubular components that are attached or otherwise coupled to each
other. In other embodiments, the tubular member 901 can be expanded
to form the larger diameter sheath jacket 912 such that the stem
region 917 and sheath jacket 912 are formed from a common tubular
member. In another embodiment or in combination with the previous
embodiments, the diameter of the stem region 917 can be
reduced.
[0123] The proximal end 905 of the inner tubular member 904 can be
connected to a handle 907 for grasping and moving the inner tubular
member 904 with respect to the outer tubular member 901. The
proximal end 902 of the outer tubular member 901 can be connected
to an outer sheath handle 908 for grasping and holding the outer
tubular member 901 stationary with respect to the inner tubular
member 904. A hemostasis seal 909 can be preferably provided
between the inner and outer tubular members 901, 904, and the
hemostasis seal 909 can be disposed in outer sheath handle 908. In
some embodiments, the outer sheath handle 908 comprises a side port
valve 921, and the fluid can be passed into the outer tubular
member through it.
[0124] In general, the inner tubular member 904 comprises a
multi-lumen hypotube (see FIG. 6). In some embodiments, a neck
section 910 is located at the proximal end 905 of the inner tubular
member 904. The neck section 910 may be made from stainless steel,
Nitinol or another suitable material which can serve to provide
additional strength for moving the inner tubular member 904 within
the outer tubular member 901. In some embodiments, a marker band
911 is present at the distal end 906 of the inner tubular member
904. The multi-lumen hypotube can have a wall thickness between
about 0.004 in and about 0.006 in. In one embodiment, the wall
thickness is about 0.0055 in, which provides sufficient column
strength and increases the bending load required to kink the
hypotube. With reference to FIG. 6, the inner tubular member 904
(i.e., multi-lumen hypotube in the illustrated embodiment) can
comprise at least four lumens. One of the lumens can accommodate
the guidewire tubing 914, and each of the other lumens can
accommodate a positioning-and-fill lumen (PFL) tubing 916. The
guidewire tubing 914 can be configured to receive a guidewire. The
PFL tubing 916 can be configured to function both as a control wire
for positioning the implant 800 at the implantation cite, and as an
inflation tube for delivering a liquid, gas or inflation media to
the implant 800. In particular, the tubing 916 can allow angular
adjustment of the implant 800. That is, the plane of the valve
(defined generally perpendicular to the longitudinal axis of the
implant 800) can be adjusted with the tubing 916.
[0125] With reference to FIGS. 5A and 5B, in general, the guidewire
tubing 914 can be longer than and can extend throughout the length
of the delivery catheter 900. The proximal end of the guidewire
tubing 914 can pass through the inner sheath handle 907 for
operator's control; the distal end of the guidewire tubing 914 can
extend past the distal end 903 of the outer tubular member 901, and
can be coupled to a guidewire tip 915. The guidewire tip 915 can
close the distal end 903 of the outer tubular member 901 (or the
receptacle) and protect the retracted implant 800, for example,
during the advancement of the delivery catheter. The guidewire tip
915 can be distanced from the outer tubular member 901 by
proximally retracting the outer tubular member 901 while holding
the guidewire tubing 914 stationary. Alternatively, the guidewire
tubing 914 can be advanced while holding the outer tubular member
901 stationary. The guidewire tubing 914 can have an inner diameter
of about 0.035 inches to about 0.042 inches, so the catheter system
is compatible with common 0.035'' or 0.038'' guidewires. In some
embodiments, the guidewire tubing 914 may have an inner diameter of
about 0.014 inches to about 0.017 inches, so the catheter system is
compatible with a 0.014'' diameter guidewire. The guidewire tubing
914 can be made from a lubricious material such as Teflon,
polypropylene or a polymer impregnated with Teflon. It can also be
coated with a lubricous or hydrophilic coating.
[0126] The guidewire tip 915 may be cone shaped, bullet shaped or
hemispherical on the front end. The largest diameter of the
guidewire tip 915 is preferably approximately the same as the
distal portion 903 of the outer tubular member 901. The guidewire
tip 915 preferably steps down to a diameter slightly smaller than
the inside diameter of the outer sheath jacket 912, so that the tip
can engage the outer sheath jacket 912 and provide a smooth
transition. In the illustrated embodiment, the guidewire tip 915 is
connected to the guidewire tube 914, and the guidewire lumen passes
through a portion of the guidewire tip 915. The proximal side of
the guidewire tip 915 also has a cone, bullet or hemispherical
shape, so that the guidewire tip 915 can easily be retraced back
across the deployed implant 800, and into the deployment catheter
900. The guidewire tip 915 can be manufactured from a rigid polymer
such as polycarbonate, or from a lower durometer material that
allows flexibility, such as silicone. Alternatively, the guidewire
tip 915 may be made from multiple materials with different
durometers. For example, the portion of the guidewire tip 915 that
engages the distal portion 903 of the outer tubular member 901 can
be manufactured from a rigid material, while the distal and or
proximal ends of the guidewire tip 915 are manufactured from a
lower durometer material.
[0127] As will be explained in detail below, in one embodiment, the
guidewire tip 915 is configured (e.g., has a tapered shape) to for
direct insertion into an access vessel over a guidewire. In this
manner, the guidewire tip 915 and the jacket 912 can be used to
directly dilate the access vessel to accommodate an introducer
catheter positioned over the delivery catheter.
[0128] Each PFL tubing 916 can extend throughout the length of the
delivery catheter 900. The proximal end of the PFL tubing 916
passes through the handle 907, and has a luer lock 917 for
connecting to fluid, gas or inflation media source. The distal end
of the PFL tubing 916 extends past the distal end 906 of the inner
tubular member 904 through the hypotube lumen. With reference to
FIG. 5C, in some embodiments, the PFL tubing 916 comprises a strain
relief section 918 at the proximal end where the tubing 916 is
connected to the luer lock 917, and the strain relief section 918
serves to relieve the strain on the PFL tubing 916 while being
maneuvered by the operator. The distal end of the PFL tubing 916
comprises a tip or needle 919 for connecting to the implant 800. In
some embodiments, the tip 919 may have a threaded section toward
the end of the needle 919 (see FIG. 5C). In some embodiments, the
PFL tubing 916 may have PFL marker(s) 920 at the distal end and/or
proximal end of the tubing 916 for identification.
[0129] The PFL tubing 916 can be designed to accommodate for the
ease of rotation in a tortuous anatomy. The tubing 916 may be
constructed using polyimide braided tube, Nitinol hypotube, or
stainless steel hypotube. In a preferred embodiment, the PFL tubing
916 is made from braided polyimide, which is made of polyimide
liner braided with flat wires, encapsulated by another polyimide
layer and jacketed with prebax and nylon outer layer. In some
embodiments, a Nitinol sleeve can be added to the proximal end of
the PFL tubing 916 to improve torque transmission, kinks resistance
and pushability. In some embodiments, the outside surface of the
PFL tubing 916 and/or the inside surface of the lumens in the
multi-lumen hypotube can also be coated with a lubricious silicone
coating to reduce friction. In some embodiments, an inner lining
material such as Teflon can be used on the inside surface of the
lumens in the multi-lumen hypotube to reduce friction and improve
performance in tortuous curves. Additionally, slippery coatings
such as DOW 360, MDX silicone or a hydrophilic coating from BSI
Corporation may be added to provide another form of friction
reducing elements. This can provide a precision control of the PFL
tubings 916 during positioning of the implant 800. In some
embodiments, the outside surface of the PFL tubing 916 can be
jacketed and reflowed with an additional nylon 12 or Relsan AESNO
layer to ensure a smooth finished surface. In some embodiments,
anti-thrombus coating can also be put on the outside surface of the
PFL tubing 916 to reduce the risk of thrombus formation on the
tubing.
[0130] In some embodiments, the outer diameter of the catheter 900
can measure between about 0.030 inches to about 0.200 inches with a
wall thickness of the outer tubular member 901 being about 0.005
inches to about 0.060 inches. In certain embodiments, the outer
diameter of the outer tubular member 901 can be between about 0.215
and about 0.219 inches. In this embodiment, the wall thickness of
the outer tubular member 901 is between about 0.005 inches and
about 0.030 inches. The overall length of the catheter 900 can
range from about 80 centimeters to about 320 centimeters. In
certain embodiments, the working length of the outer tubular member
901 (from the distal end of the sheath jacket 912 to the location
where the tubular member 901 is connected to the outer sheath
handle 908) can be about 100 cm to about 120 cm. In some
embodiments, the inner diameter of the sheath jacket 912 can be
greater than or equal to about 0.218 inches, and the outer diameter
of the sheath jacket 912 is less than or equal to about 0.241
inches. In a preferred embodiment, the outer diameter of the sheath
jacket portion 912 can be less than or equal to about 0.236 inches
or 18 French. In some embodiments, the outer diameter of the PFL
tubing 916 can be less than or equal to about 0.0435 inches, and
the length is about 140 cm to about 160 cm.
[0131] In the embodiments that employ a low crossing profile outer
tubular member, a low profile inflatable implant in a retracted
state is preferable for fitting into the sheath jacket 912. The
sheath jacket 912 can have an outer diameter of 18 French or less.
In some embodiments, the implant 800 comprises a tissue valve 104
with an expanded outer diameter greater than or equal to about 22
mm and a tissue thickness of greater than or equal to about 0.011
inches. The compressed diameter of the implant 800 may be less than
or equal to about 6 mm or 18 French. The retracted implant 800 is
generally loaded between the distal portion 903 of the outer
tubular member 901 and the distal portion 906 of the inner tubular
member 904. The distal portion 903 of the outer tubular member 901
therefore can form a receptacle for the implant 800. The implant
800 can be exposed or pushed out of the receptacle by holding the
implant 800 stationary as the outer tubular member 901 is
retracted. Alternatively, the outer tubular member 901 can be held
stationary while the inner tubular member 904 is advanced and
thereby pushing the implant 800 out of the receptacle.
[0132] The delivery system can include a loading tool base 925 that
can connect to the PFL tubing 916. In some embodiments, the PFL
tubing 916 can connect to the loading tool base 921 via a luer
connection. With reference to FIG. 7, one end of the loading tool
base 921 can be configured to have step edge 923s. In some
embodiments, the distal end of the loading tool base has three step
edges 923, each step edge 923 has a luer connector 924 for
connecting the PFL tubing 916. In some embodiments, the loading
tool base 921 can also comprise at least two additional connectors
922 (e.g. additional luer connectors), each in fluid communication
with one of the luer connector 924 on the stepped edges 923, which
would allow the introduction of fluid, gas or air into the implant
800 for testing purposes. For example, in the exemplified
embodiment, once the PFL tubings 916 are connected to the loading
tool base 921, a liquid or air source can be connected to the
loading tool base 921 via the additional connectors 922. The liquid
or air can then be introduced into the implant 800 through the
loading tool base 921 and the PFL tubings 916.
[0133] The step edges 923 on the loading tool base 921 can allow
the implant 800 to be collapsed or folded up tightly so it can be
loaded into the sheath jacket 912 at the distal end of the outer
tubular member 901. When the proximal end of the PFL tubings 916
are connected to the loading tool base 921 and the distal end
connected to the connection ports 809 of the implant 800, the step
edge connections can pull the PFL tubings 916 in a way that creates
an offset of the inflation valves 810 and/or the connection ports
809 in the inflation channels 808 when the implant 800 is folded or
collapsed. By staggering the connection ports/inflation valves, the
collapsed implant 800 can have a reduced cross-sectional profile.
In some embodiments, the check valve 814 in the inflation channel
is also staggered with the connection ports/inflation valves in the
collapsed state. Accordingly, in one embodiment, the inflation
valves 810 and/or the connection ports 809 are axially aligned when
the valve is positioned within the deployment catheter in a
collapsed configuration. That is, the inflation valves 810 and/or
the connection ports 809 and/or check valve 814 are positioned such
that they do not overlap with each other but are instead aligned
generally with respect to the longitudinal axis of the deployment
catheter. In this manner, the implant 800 can be collapsed into a
smaller diameter as opposed to a configuration in which with the
inflation valves 810 and/or the connection ports 809 and/or check
valve 814 overlap each other in a radial direction, which can
increase the diameter of the compressed implant 800. In a similar
manner, the channels 806 can be arranged positioned such hat they
also do not overlap with each other. The loading tool base 925 can
be used to pull one end of the distal and proximal rings 807a, 807b
in a proximal direction so as to align the inflation valves 810
and/or the connection ports 809 and/or check valve 814 axially as
described above and/or align the channels so as to reduce the
overlap between multiple channels 806.
Combined Delivery System with Delivery Catheter and Introducer
Catheter
[0134] FIG. 8A illustrates an exemplary embodiment of a combined
delivery system 1000 that can be used to deliver an implant 800,
such as the implant embodiments described above. The combined
delivery system 1000 can include an introducer catheter 1030 and
that is positioned at least partially over the delivery catheter
900 described above. As will be explained in more detail below, in
certain arrangements, it is advantageous to use the combined
delivery system 1000 because the introducer catheter 1030 can have
a smaller diameter than would possible if the introducer catheter
1030 and the delivery catheter 900 are separately introduced into
the patient. For example, in the illustrated embodiment, the sheath
jacket 912 of the delivery catheter 900 can have an outer diameter
that is too large to be inserted through the introducer catheter
1030 (i.e., the outer diameter of the sheath jacket 912 can be
larger than the inner diameter of the introducer catheter 1030 and
in some embodiments the outer diameter of the sheath jacket 912 can
be the same or substantially the same as the outer diameter of the
introduce catheter). Accordingly, by preassembling or building the
introducer catheter 1030 over a proximal portion of the delivery
catheter 900, a reduced diameter combined delivery system 1000 can
be created. In one embodiment, the introducer catheter 1030 is a 16
French introducer catheter capable of receiving a 16 French
catheter. The outer diameter the sheath jacket 912 of the delivery
catheter 900 and a distal end of the introducer catheter 1030 can
be about 18 French or smaller. It is believed that such a combined
delivery system 1000 has a smaller outer diameter than any known
approved delivery system and introducer systems for transcatheter
heart valves. The smaller delivery system size can reduce vascular
complications such as aortic dissection, access site or access
related vascular and/or distal embolization from a vascular source
particularly in situations in which the patient's femoral artery
has a smaller diameter.
[0135] FIG. 9 illustrates the introducer catheter 1030 of the
illustrated embodiment in more detail. In general, the introducer
catheter 1030 can comprise an elongate catheter having a proximal
end 1032 and a distal end 1034. In some embodiments, the distal end
1034 of the introducer catheter 1030 can be tapered. The introducer
catheter 1030 can comprise a seal assembly 1042 positioned at the
proximal end 1032 of the introducer catheter 1030.
[0136] An inner diameter of the introducer catheter 1030 can be
smaller than an outer diameter of a distal portion of the delivery
catheter 900. In some embodiments, the inner diameter of the
introducer catheter 1030 is about 16 French or less. In some
embodiments, the introducer catheter 1030 can comprise a
commercially available introducer catheter having an appropriate
diameter. For example, in some embodiments, the introducer catheter
1030 is a 16F introducer catheter commercially available from Cook
Medical.RTM..
[0137] The seal assembly 1042 (see FIG. 10B) can threadably engage
the proximal end 1032 of the introducer catheter 1030. The seal
assembly 1042 can include a seal member 1046 configured to form a
seal around the delivery catheter 900. The seal assembly 1042 can
be adjusted to maintain the position of the introducer catheter
1030 relative to the delivery catheter 900 during the procedure. In
some embodiments, the seal assembly 1042 comprises a hemostasis
seal/valve configured to minimize blood loss during percutaneous
procedures. In some embodiments, the seal assembly 1042 comprises a
flush port 1044.
[0138] As discussed above, in general, the combined delivery system
1000 comprises the delivery catheter 900, which extends through the
introducer catheter 1030. In the illustrated embodiment, the
components of the delivery catheter 900 can be the same, similar,
or identical to the corresponding components of the low crossing
profile delivery catheter 900 discussed above accordingly.
Accordingly, for the sake of brevity only certain components of the
delivery catheter 900 will be described below.
[0139] As noted above, the delivery catheter 900 can include outer
tubular member 901 having a proximal end 902 and a distal end 903,
and an inner tubular member 904 also having a proximal end 905 and
a distal end 906. The inner tubular member 904 extends generally
through the outer tubular member 901, such that the proximal and
distal ends 902, 903 of the inner tubular member 904 extend
generally past the proximal end 902 and distal end 903 of the outer
tubular member 901. In some embodiments, the delivery catheter 900
extends generally through the introducer catheter 1030, such that
the proximal end 902 and the distal end 903 of the delivery
catheter 900 extend generally past the proximal end 1032 and the
distal end 1034 of the introducer catheter 1030.
[0140] In several embodiments, the outer diameter of the distal
portion of the delivery catheter 900 and in particular, the sheath
jacket 912, is larger than an inner diameter at the distal end of
the introducer catheter 1030. In some embodiments, the outer
diameter of the delivery catheter 900 is about 18 French or less,
particularly at the distal portion of the delivery catheter 900. In
some embodiments, the outer diameter at the proximal portion of the
delivery catheter 900 is about 16 French or less. In FIGS. 8A and
8B, the outer diameter of the sheath jacket 912, the proximal
portion of the guidewire tip 915 and the introducer catheter 1030
are illustrated as having different outer diameters. However, in
certain arrangements, the outer diameters of these components 912,
915 and 1030 can be the same or substantially the same and the
outer tubular member 901 can have a smaller outer diameter than
these components. In certain arrangements, the sheath jacket 912
and the proximal portion of the guidewire tip 915 can have the same
outer diameter or substantially same outer diameter as the proximal
portions of the introducer catheter 1030.
[0141] FIG. 10 illustrates a closer view of the outer tubular
member 901. The distal end 903 of the outer tubular member 901 can
form the sheath jacket 912. As noted above, the sheath jacket 912
can house the implant 800 in a retracted state for delivery to the
implantation site. In some embodiments, an outer diameter of the
sheath jacket 912 is larger than an outer diameter of stem portion
917 of the outer tubular member 901. In the illustrated embodiment,
the outer diameter of the sheath jacket 912 is larger than the
inner diameter of at the distal end of the introducer catheter 1030
while the stem portion 912 has an outer diameter that is smaller
than the inner diameter of the introducer catheter 1030. In some
embodiments, the outer diameter of the sheath jacket 912 is about
18F or less. In some embodiments, the outer diameter of the stem
portion 917 of the outer tubular member 901 is 16F or less. As
described above, in some embodiments, the sheath jacket 912 is a
separate component connected to the step portion 917 of the outer
tubular member 901, while in other embodiments, the sheath jacket
912 is integrally formed with the proximal of the outer tubular
member 901.
[0142] As explained above, in some arrangements, it can be
advantageous to use the combined delivery system 1000 to reduce the
diameter of the introducer catheter 1030 used to deliver the
delivery catheter 900 to a treatment site. If the introducer
catheter 1030 and delivery catheter 900 are separately introduced,
the inner diameter of the introducer catheter 1030 has to be
greater than the outer diameter of the largest portion of the
delivery catheter 900 to be introduced into the patient. In
contrast, in several embodiments of the combined delivery system
1000, the outer diameter of the distal portion of the delivery
catheter 900 is greater than the inner diameter of the introducer
catheter 1030. For example, in some embodiments, the outer diameter
of the distal portion of the delivery catheter 900 is about 18
French, and the outer diameter of the proximal portion of the
delivery catheter 900 is about 16 French. In some embodiments, the
inner diameter of the introducer catheter 1030 is about 16 French.
In some embodiments, the introducer catheter 1030 can be
pre-installed over the proximal portion of the delivery catheter
900.
Method of Deployment Using the Combined Delivery System
[0143] In several embodiments, an implant 800 may be deployed in an
aortic position using the combined delivery system 1000 described
above and a minimally invasive procedure. In some embodiments, the
method generally comprises gaining access to the aorta, most often
through the femoral artery. The vascular access site can be
prepared according to standard practice, and the guidewire can be
inserted into the left ventricle through the vascular access.
[0144] As shown in FIG. 8A and as described above, the introducer
catheter 1030 can be pre-installed over the delivery catheter 900
prior to performing the minimally invasive procedure. For example,
the manufacturer can pre-install the introducer catheter 1030 over
the delivery catheter 900. In some embodiments, the manufacturer
extends the delivery catheter 900 through the introducer catheter
1030 prior to completing assembly of the combined delivery system
1000. For example, in some arrangements, it can be desirable to
extend the delivery catheter 900 through the introducer catheter
1030 prior to attaching a handle to the proximal end 902 of outer
tubular member 901. In other arrangements, it can be desirable to
extend the delivery catheter 900 through the introducer catheter
prior to attaching the sheath jacket 912 or implant 800 to the
distal end 940 of the delivery catheter 900.
[0145] In other embodiments, the operator (e.g., a nurse,
physician, or other individual) extends the delivery catheter 900
through the introducer catheter 1030 prior to inserting the
introducer catheter 1030 or delivery catheter 900 into the patient.
In some embodiments, the handle of the outer tubular member 901 can
be removable, thus allowing the user to remove the handle and
extend the delivery catheter 900 through the introducer catheter
1030 prior to inserting the introducer catheter 1030 or delivery
catheter 900 into the patient.
[0146] In some embodiments, after the manufacturer or operator
extends the delivery catheter 900 through the introducer catheter
1030, a distal portion of the delivery catheter 900 extends
distally from the distal end 1034 of the introducer catheter 1030.
In some embodiments, the distal sheath jacket 912 or implant 800
extends distally from the distal end 1034 of the introducer
catheter 1030.
[0147] After the combined delivery system 1000 is assembled, as
shown in FIG. 10, the combined delivery system 1000 carrying the
cardiovascular prosthetic implant 800 can be translumenally
advanced. In some embodiments, the combined delivery system 1000 is
inserted over the guidewire. In such embodiments, the guidewire tip
915 can be inserted directly into the access vessel over the
guidewire such that the guidewire tip dilates the access vessel for
the introducer catheter 1030. In some embodiments, the combined
delivery system 1000 is advanced until the seal assembly 1042
reaches the patient. In other embodiments, the introducer catheter
1030 is held in place while the delivery catheter 900 is further
advanced as shown in FIG. 8B. The delivery catheter 900 can be
advanced to a position proximate a native valve. In other
embodiments, the entire combined delivery system 1000, including
both the introducer catheter 1030 and the delivery catheter 900 can
be advanced to a position proximate a native valve.
[0148] After the delivery catheter 900 is advanced over the aortic
arch and past the aortic valve, the position of the outer tubular
member 901 relative to the introducer catheter 1030 can be
maintained by adjusting the seal assembly 1042 to form a seal
around the outer tubular member 901.
[0149] As shown in FIG. 8C, in some embodiments, the implant 800
can be revealed or exposed by retracting the outer tubular member
901 partially or completely while holding the inner tubular member
904 stationary and allowing proper placement at or beneath the
native valve. In some embodiments, the implant can also be revealed
by pushing the inner tubular member 904 distally while holding the
outer tubular member 901 stationary. Once the implant 800 is
unsheathed, it may be moved proximally or distally, and the fluid
or inflation media may be introduced to the cuff 802 providing
shape and structural integrity. In some embodiments, the distal
toroid of the inflatable cuff or inflatable structure is inflated
first with a first liquid, and the implant 800 is positioned at the
implantation cite using the links between the implant 800 and the
combined delivery system 1000. In some embodiments, no more than
three links are present. In some embodiments, the links are PRL
tubes 916, which can be used to both control the implant 800 and to
fill the inflatable cuff. The implant 800 may be otherwise inflated
or controlled using any of the other methods disclosed above.
[0150] In some embodiments, the links are PRL tubes 916, which can
be used to both control the implant 800 and to fill the inflatable
cuff.
[0151] The deployment of the implant 800 can be controlled by the
PFL tubes 916 that are detachably coupled to the implant 800. The
PFL tubes 916 are attached to the cuff 802 of the implant 800 so
that the implant 800 can be controlled and positioned after it is
removed from the sheath or delivery catheter 900. Preferably, three
PFL tubes 916 are used, which can provide precise control of the
implant 800 PFL tubes 916 during deployment and positioning. The
PFL tubes 916 can be used to move the implant 800 proximally and
distally, or to tilt the implant 800 and change its angle relative
to the native anatomy.
[0152] In some embodiments, the implant 800 contains multiple
inflation valves 810 to allow the operator to inflate specific
areas of the implant 800 with different amounts of a first fluid or
a first gas. With reference to FIGS. 11A-C, in some embodiments,
the implant 800 is initially deployed partially in the ventricle 32
(FIG. 11A). The inflation channel 808 is filled partially, allowing
the distal portion of the implant 800 to open to approximately its
full diameter. The implant is then pulled back into position at or
near the native valve 34 annulus (FIG. 11B). In some embodiments,
the distal toroid 807b is at least partially inflated first, and
the cardiovascular prosthetic implant 800 is then retracted
proximally for positioning the cuff across the native valve 34. The
distal ring 807b seats on the ventricular side of the aortic
annulus, and the implant 800 itself is placed just above the native
valve 34 annulus in the aortic root. At this time, the PFL tubes
916 may act to help separate fused commissures by the same
mechanism a cutting balloon can crack fibrous or calcified lesions.
Additional inflation fluid or gas may be added to inflate the
implant 800 fully, such that the implant 800 extends across the
native valve annulus extending slightly to either side (See FIG.
11C). The PFL tubes 916 provide a mechanism for force transmission
between the handle of the deployment catheter 900 and the implant
800. By moving all of the PFL tubes 916 together or the inner
tubular member 904, the implant 800 can be advanced or retracted in
a proximal or distal direction. By advancing only a portion of the
PFL tubes 916 relative to the other PFL tubes 916, the angle or
orientation of the implant 800 can be adjusted relative to the
native anatomy. Radiopaque markers on the implant 800 or on the PFL
tubes 916, or the radio-opacity of the PFL tubes 916 themselves,
can help to indicate the orientation of the implant 800 as the
operator positions and orients the implant 800.
[0153] In some embodiments, the implant 800 has two inflation
valves 810 at each end of the inflation channel 808 and a check
valve 811 in the inflation channel 808. The check valve 811 is
positioned so the fluid or gas can flow in the direction from the
proximal toroid 807a to the distal toroid 807b. In some
embodiments, the implant 800 is fully inflated by pressurizing the
endoflator attached to the first PFL tube 916 that is in
communication with the first inflation valve 810 that leads to the
proximal toroid 807a, while the endoflator attached to the second
inflation valve 810 that is in communication with the distal toroid
807b is closed. The fluid or gas can flow into the distal toroid
807b through the one-way check valve. The proximal toroid 807a is
then deflated by de-pressurizing the endoflator attached to the
second inflation valve. The distal toroid 807b will remain inflated
because the fluid or gas cannot escape through the check valve 811.
The implant 800 can then be positioned across the native annulus.
Once in the satisfactory placement, the proximal toroid 807a can
then be inflated again.
[0154] In some embodiments, the implant 800 may only have one
inflation valve. When the inflation channel 808 is inflated with
the first fluid or gas, the proximal portion of the implant 800 may
be slightly restricted by the spacing among the PFL tubes 916 while
the distal portion expands more fully. In general, the amount that
the PFL tubes 916 restricts the diameter of the proximal end of the
implant 800 depends on the length of the PFL tubes 916 extend past
the outer tubular member 901, which can be adjusted by the
operator. In other embodiments, burst discs or flow restrictors are
used to control the inflation of the proximal portion of the
implant 800.
[0155] The implant 800 can also be deflated or partially deflated
for further adjustment after the initial deployment. As shown in
FIG. 12A, the implant 800 can be partially deployed and the PFL
tubes 916 used to seat the implant 800 against the native aortic
valve 34. The implant 800 can then be fully deployed as in shown in
FIG. 12B and then tested as shown in FIG. 13C. If justified by the
test, the implant 800 can be deflated and moved as shown in FIG.
12D to a more optimum position. The implant 800 can then be fully
deployed and released from the control wires as shown in FIG.
12E.
[0156] As discussed above, in some embodiments, the first inflation
fluid or gas can be displaced by an inflation media that can harden
to form a more permanent support structure in vivo. Once the
operator is satisfied with the position of the implant 800, the PFL
tubes 916 are then disconnected, and the catheter is withdrawn
leaving the implant 800 behind (see FIG. 12C), along with the
hardenable inflation media. The inflation media is allowed to
solidify within the inflatable cuff. The disconnection method may
included cutting the attachments, rotating screws, withdrawing or
shearing pins, mechanically decoupling interlocked components,
electrically separating a fuse joint, removing a trapped cylinder
from a tube, fracturing a engineered zone, removing a colleting
mechanism to expose a mechanical joint or many other techniques
known in the industry. In modified embodiments, these steps may be
reversed or their order modified if desired.
[0157] In some arrangements, it may be desirable to deliver a
cardiovascular prosthetic implant 800 using a combined delivery
system 1000 to reduce the number of components and steps necessary
to position the cardiovascular prosthetic implant 800. For example,
if the introducer catheter is inserted separately from the delivery
catheter, the operator uses a dilator to facilitate delivery of the
introducer catheter. In some scenarios, the dilator includes a
flexible, elongate catheter body and a generally cone-shaped tip.
The dilator is often a separate component that extends through the
introducer catheter and must be removed after the introducer
catheter is delivered to the appropriate position. After the
dilator is removed, the operator inserts the delivery catheter
through the introducer catheter. It can be advantageous to
eliminate the use of the dilator or eliminate the catheter exchange
step by delivering the cardiovascular prosthetic implant 800 using
a combined delivery system 1000. Instead of relying on the separate
dilator component, the combined delivery system 1000 can use the
guidewire tip 915 to function as the dilator. As described above,
in some embodiments, the guidewire tip 915 can be cone-shaped,
bullet-shaped, or hemispherical-shaped to facilitate dilation.
Further, the diameter of the guidewire tip 915 can be configured to
form a smooth transition from the distal end of the sheath jacket
912 to the guidewire tip 915. The smooth transition can help
prevent the distal end of the introducer catheter 1030 from
damaging a vessel wall.
[0158] In certain arrangements, it is advantageous to deliver a
cardiovascular prosthetic implant 800 using a combined delivery
system 1000 to reduce the number steps necessary to remove the
combined delivery system 1000 after the implant 800 is delivered to
the appropriate location. For example, if the introducer catheter
is inserted separately from the delivery catheter, the delivery
catheter can be completely removed from the patient before the
introducer catheter is removed from the patient. In some scenarios,
it can be desirable to remove both the introducer catheter and
delivery catheter simultaneously using the combined delivery system
1000. After the implant 800 is delivered to the appropriate
location, the PFL tubing 916 can be retracted proximally into the
inner tubular member 904. In some embodiments, the delivery
catheter 900 is retracted proximally until a proximal end of the
sheath jacket 912 abuts the distal end 1034 of the introducer
catheter 1030. The guidewire tubing 914 can be retracted proximally
until the guidewire tip 915 closes the distal end of the outer
tubular member 901 and forms a smooth transition from the distal
end 1034 of the introducer catheter 1030 to the guidewire tip 915.
The smooth transition can help prevent the distal end 1034 of the
introducer catheter 1030 from damaging the blood vessel as the
introducer catheter is removed from the patient. The introducer
catheter 1030 and the delivery catheter 900 can then be removed
from the patient simultaneously.
[0159] With the integral introducer, it is desirable to have a
relatively long tapered tip to facilitate introduction through
tortuous arteries and tensioning of the sutures for arterial
closure upon device removal, but for safe deployment in the
relatively small ventricle it is desirable to have a tip that does
not take up too much space. Several embodiments addressing this
issue are described. These embodiments can be used in combination
with the various embodiments described above.
[0160] In a first embodiment shown in FIG. 13, the distal portion
of the catheter tip 927 can be about 2 to 8 cm, similar to a
dilator introducer for a similarly sized introducer, but is
extremely flexible, so that it can follow the curve of the
guidewire 914 inside the ventricle (see e.g., FIG. 14). In one
embodiment the tip is manufactured from a material such as silicone
or urethane with a durometer of less than about 25A. In another
embodiment the outer surface of the tip 927 is substantially
continuous but material from the internal volume of the tip is
omitted allowing the tip to flex. Preferably the tip 927 is capable
of bending to a radius of less than 3 cm with less than 1 lb force.
More preferably the tip 927 is capable of bending to a radius of
less than 3 cm with less than 0.5 lb force. In another embodiment
the tip 927 has a preset curve with a radius of approximately 2 to
8 cm or more preferably about 3 to 5 cm. Preferably the curved tip
927 is substantially straightened when placed over the stiff
section of a very stiff 0.035 guidewire 914, and returns to a
curved shape over the flexible or curved distal section of the
guidewire 914. Preferably the tip 927 is radiopaque. This can be
accomplished by filling the tip 927 with a radiopaque material such
as barium sulfate, tungsten or tantalum.
[0161] In another embodiment the device has a long tip in one
configuration and a short tip in a second configuration, where the
long tip is greater than about 3 cm and the short tip is less than
about 3 cm. In a similar embodiment the long tip is greater than
about 2 cm and the short tip is less than about 2 cm. The device is
advanced through the iliac arteries in the long tip configuration
and advanced near the treatment location into the ventricle in the
short tip configuration. In one embodiment a long tip fits over a
short tip and is held in place by at least one tension member which
extends to a proximal portion of the device. After the device has
passed through the challenging access site the tension members are
loosened allowing the long tip to move away form the short tip, but
containing it for later removal.
[0162] In another embodiment the tip has a straight configuration
and a bent configuration and can be oriented from one configuration
to the other by devices of a mechanism such as a pullwire.
[0163] In another embodiment the tip is inflatable, achieving a
long configuration when pressurized and a short configuration when
deflated, or when a vacuum is applied.
[0164] When treating a patient with the integral introducer sheath
it is typically to introduce the device with the guidewire already
in position across the aortic valve. In some cases this can present
a challenge or risk to keep the guidewire in proper position during
device insertion. The embodiments describe herein include several
methods to facilitate crossing the native valve with the guidewire
after the device is inserted
[0165] In one embodiment the guidewire exits the distal tip of the
guidewire at an angle at least 5 degrees from the axis of the
delivery system, and preferably between 10 and 40 degrees. This
allows the delivery catheter to be rotated to point the guidewire
directly at the aortic valve to allow easy crossing of the valve
with the guidewire. In one embodiment the shape of the tip is
similar to the shape of a coronary guide catheter commonly used to
cross the aortic valve.
[0166] In another embodiment the tip is deflectable and the bend of
the tip can be selected by the operator. In one embodiment this is
accomplished by use of a pull wire.
[0167] One embodiment includes a steerable guidewire as an
accessory. Steerable guidewires are commonly known in the art.
[0168] In another embodiment a lumen is provided with a bend near
the distal end and an outside diameter of approximately 0.035 or
configured so that it passes through the guidewire lumen. The
inside diameter of the lumen is configured so that a 0.032, 0.018
or 0.014 or 0.009 guidewire can pass through it. This additional
lumen can be used to control the guidewire and facilitate crossing
the aortic valve with the guidewire.
[0169] When treating a patient with the integral introducer sheath
it is typically necessary to introduce the device with the
guidewire already in position across the aortic valve. In some
cases this can present a challenge or risk to keep the guidewire in
proper position during device insertion. The embodiments described
herein include several methods to minimize the difficulty and risk
of the sheath exchange.
[0170] In one embodiment the guidewire lumen exits the catheter at
least 5, 10 20 or 50 cm distal to the proximal end of the catheter.
This allows a single operator to control the guidewire position
during the removal of the smaller sheath and the insertion of the
device. I
[0171] In one embodiment the guidewire passes through a lumen in
the tip, where one end of the lumen is at approximately the distal
end of the tip and the second end of the lumen is near a side of
the tip distal to where the tip is in contact with the sheath
portion of the delivery catheter. This provides the benefits of
single operator guidewire control while additionally allowing the
connection to the tip to be of smaller cross sectional area,
allowing for further profile reduction.
[0172] When treating a patient with the integral introducer sheath
it may be desirable to have a larger diameter sheath for certain
manipulations that are not used in all procedures, such as
retrieval of the implant. In some embodiments the introducer can
expand in these situations but maintains the low profile of the
device during normal use. The expandable introducer may be of a
design similar to the e-sheath marketed by Edwards Lifesciences or
of a design similar to one marketed by onset medical. In another
embodiment the introducer sheath can be made from a polymer in a
tubular cross section that expands during retrieval through elastic
and plastic deformation. The expanded configuration is preferably
at least 10 percent larger than the non-expanded configuration. The
ID of the expanded configuration is preferably similar to the OD of
the non-expanded configuration. The ID of the expanded
configuration is preferably larger than the OD of the non-expanded
configuration.
[0173] For the withdrawal of the device with the integral sheath,
especially when used with percutaneous closure techniques utilizing
device such as prostar or proglide marketed by Abbot Laboratories,
it is preferable to be able to tighten the sutures on the tapered
tip of the device as the device is being removed from the patient.
To facilitate easy removal the preferred embodiments have a
mechanism to lock the tip to the catheter body and or the catheter
body to the introducer sheath, so that by pulling back on a single
component while cinching the sutures is a simple procedure
requiring a minimum of coordination between multiple operators.
[0174] In one embodiment the tip and the largest diameter portion
of the outer sheath are collapsible to facilitate their removal
through an integral introducer that is not substantially
expandable. In one embodiment the components are mechanically
collapsible such that by providing axial force to pull the
components into the introducer sheath they collapse. In one
embodiment the tip is made from nylon 12 with a hollow cross
section and a wall thickness of between 0.005 and 0.050 in.
[0175] In one embodiment the lock mechanism is a cam located in the
proximal handle that locks the guidewire lumen to the catheter
body, substantially preventing relative motion between the catheter
body and the tip. In another embodiment a lock mechanism is a
toughy-borst type valve located on the proximal end of the integral
introducer sheath that can be tightened to prevent relative motion
between the integral introducer sheath and the catheter body.
[0176] For the withdrawal of the device with the integral sheath,
especially when used with percutaneous closure techniques utilizing
device such as prostar or proglide marketed by Abbot laboratories,
it is important to know the relative location of the tip, the
distal and proximal ends of the large diameter portion of the
delivery device and the distal portion of the integral introducer
sheath.
[0177] One embodiment of the device includes radiopaque markers at
the locations described above. In another embodiment a visible mark
on the outer portion of the delivery device that when aligned with
a visible mark or edge of the bub of the integral introducer,
indicates that the proximal end of the large diameter portion of
the delivery device is aligned with the distal end of the delivery
catheter.
[0178] One embodiment includes an accessory device for accessing
difficult iliac anatomies. An inverted tip balloon is inserted
though the contralateral side, and advanced through the aortic
bifurcation back into the access vessel. The inverted tip allows
the guidewire to be advanced through the device, and then through
the guidewire lumen of the inverted tip balloon. The balloon can be
advanced close to the device so that the tip of the device is
inside the inverted tip of the balloon. The device can be advanced
through severe calcification and tortuosity by inflating the
balloon and advancing the system with the balloon. The inverted tip
balloon has an OD similar to the OD of the delivery system,
preferably between 3 mm and 8 mm. The balloon has a rated burst
pressure between 2 and 20 atmospheres and preferably a guidewire
lumen of approximately 0.036 in diameter. The balloon preferably
has low compliance to maintain the inverted tip shape at pressure
and allow dilation of the vessel to the size needed for device
delivery without causing unnecessary trauma.
[0179] The above-describe methods generally describes an embodiment
for the replacement of the aortic valve. However, similar or
modified methods could be used to replace the pulmonary valve or
the mitral or tricuspid valves. For example, the pulmonary valve
could be accessed through the venous system, either through the
femoral vein or the jugular vein. The mitral valve could be
accessed through the venous system as described above and then
trans-septaly accessing the left atrium from the right atrium.
Alternatively, the mitral valve could be accessed through the
arterial system as described for the aortic valve, additionally the
catheter can be used to pass through the aortic valve and then back
up to the mitral valve. Additional description of mitral valve and
pulmonary valve replacement can be found in U.S. Patent Publication
No. 2009/0088836 to Bishop et al.
[0180] The various methods and techniques described above provide a
number of ways to carry out the embodiments described herein. Of
course, it is to be understood that not necessarily all objectives
or advantages described may be achieved in accordance with any
particular embodiment described herein. Thus, for example, those
skilled in the art will recognize that the methods may be performed
in a manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
objectives or advantages as may be taught or suggested herein.
[0181] Furthermore, the skilled artisan will recognize the
interchangeability of various features from different embodiments
disclosed herein. Similarly, the various features and steps
discussed above, as well as other known equivalents for each such
feature or step, can be mixed and matched by one of ordinary skill
in this art to perform methods in accordance with principles
described herein. Additionally, the methods which is described and
illustrated herein is not limited to the exact sequence of acts
described, nor is it necessarily limited to the practice of all of
the acts set forth. Other sequences of events or acts, or less than
all of the events, or simultaneous occurrence of the events, may be
utilized in practicing the embodiments of the invention.
[0182] Although the invention has been disclosed in the context of
certain embodiments and examples, it will be understood by those
skilled in the art that the invention extends beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses and obvious modifications and equivalents thereof.
Accordingly, the invention is not intended to be limited by the
specific disclosures of preferred embodiments herein
* * * * *