U.S. patent application number 09/133978 was filed with the patent office on 2001-09-20 for endovascular graft.
Invention is credited to CHOBOTOV, MICHAEL V..
Application Number | 20010023369 09/133978 |
Document ID | / |
Family ID | 26755268 |
Filed Date | 2001-09-20 |
United States Patent
Application |
20010023369 |
Kind Code |
A1 |
CHOBOTOV, MICHAEL V. |
September 20, 2001 |
ENDOVASCULAR GRAFT
Abstract
An endovascular graft which is configured to conform to the
morphology of the vessel to be treated and which is made from an
inflatable structure having a proximal end with a proximal
inflatable cuff and a distal end with a distal inflatable cuff. At
least one elongated inflatable channel is disposed between and in
fluid communication with fluid tight chambers of the inflatable
cuffs which may contain rupture discs therebetween which can be
configured to rupture at different pressures. A thin flexible
barrier disposed between the inflatable cuffs and the elongated
inflatable channel of the frame so as to form a tubular structure
defining a longitudinal channel to confine a flow of blood or other
fluid therethrough. The graft may also have an expansion member
attached to the proximal end of the graft which is preferably made
of linked expandable rings of pseudoelastic shape memory alloy
which is self expanding and prevents axial displacement of the
graft once it is deployed.
Inventors: |
CHOBOTOV, MICHAEL V.; (SANTA
ROSA, CA) |
Correspondence
Address: |
EDWARD J LYNCH
HELLER EHRMAN WHITE & MCAULIFFE
525 UNIVERSITY AVENUE
PALO ALTO
CA
943011900
|
Family ID: |
26755268 |
Appl. No.: |
09/133978 |
Filed: |
August 14, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60074112 |
Feb 9, 1998 |
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Current U.S.
Class: |
623/1.11 |
Current CPC
Class: |
A61F 2002/075 20130101;
A61F 2250/0071 20130101; A61F 2/958 20130101; A61F 2002/065
20130101; A61F 2/945 20130101; A61F 2220/0075 20130101; A61F 2/915
20130101; A61F 2250/0003 20130101; A61F 2/90 20130101; A61F 2/07
20130101; A61F 2/06 20130101; A61F 2230/0034 20130101; A61F
2250/0039 20130101 |
Class at
Publication: |
623/1.11 |
International
Class: |
A61F 002/06 |
Claims
What is claimed is:
1. An endovascular graft comprising: a) a tubular structure having
a proximal end and a distal end; and b) at least one inflatable
cuff disposed at an end of said tubular structure.
2. The endovascular graft of claim 1 further comprising an
expansion member secured to an end of said tubular structure.
3. The endovascular graft of claim 2 wherein an inflatable cuff and
the expansion member are disposed at the proximal end of the
tubular structure.
4. The endovascular graft of claim 3 wherein the inflatable cuff
disposed at the proximal end of the tubular structure is configured
to sealingly engage an interior surface of a vessel wall.
5. The endovascular graft of claim 1 further comprising a proximal
neck portion having a proximal inlet axis which forms an angle up
to about 45 degrees with a longitudinal axis of the tubular body
member.
6. An endovascular graft comprising: a) an inflatable frame
structure having a proximal end and a distal end, with a proximal
inflatable cuff disposed at the proximal end, and at least one
elongated inflatable channel in fluid communication with the
proximal inflatable cuff; and b) a thin flexible layer member
disposed between the proximal inflatable cuff, and the elongated
inflatable channel of the frame to form a longitudinal channel.
7. The endovascular graft of claim 6 further comprising at least
one expansion member secured to an end of the frame structure and
extending axially therefrom.
8. The endovascular graft of claim 7 wherein the expansion member
is comprised of linked expandable rings.
9. The endovascular graft of claim 8 wherein the linked expandable
rings are comprised of a pseudoelastic shape memory alloy.
10. The endovascular graft of claim 9 wherein the linked expandable
rings further comprise outward directed protuberances.
11. The endovascular graft of claim 6 further comprising a rupture
disc disposed between a fluid tight chamber of the proximal
inflatable cuff and a fluid tight chamber of the elongated
channel.
12. The endovascular graft of claim 6 wherein the thin flexible
layer is disposed over, at least partially surrounds, and is
secured to the inflatable frame.
13. The endovascular graft of claim 6 wherein the thin flexible
layer is disposed within and secured to the inflatable frame.
14. The endovascular graft of claim 6 further comprising a proximal
neck portion secured to the proximal end of the inflatable frame
structure.
15. The endovascular graft of claim 14 wherein the proximal neck
portion tapers proximally to a reduced diameter.
16. The endovascular graft of claim 14 wherein the proximal neck
portion tapers proximally to an increased diameter.
17. The endovascular graft of claim 6 further comprising a distal
neck portion.
18. The endovascular graft of claim 17 wherein the distal neck
portion tapers distally to a reduced diameter.
19. The endovascular graft of claim 17 wherein the distal neck
portion tapers distally to an increased diameter.
20. The endovascular graft of claim 16 further comprising a distal
neck portion that tapers distally to a increased diameter.
21. The endovascular graft of claim 14 wherein the proximal neck
portion further comprises a proximal inlet axis which forms an
inlet axis angle with a longitudinal axis of the endovascular
graft.
22. The endovascular graft of claim 21 wherein the inlet axis angle
is up to about 50 degrees.
23. The endovascular graft of claim 21 wherein the inlet axis angle
is about 20 to about 30 degrees.
24. The endovascular graft of claim 7 wherein an expansion member
is secured to the proximal end of the frame structure and has an
inlet axis which forms an angle with respect to a longitudinal axis
of the endovascular graft of up to about 40 degrees.
25. An endovascular graft comprising: a) a tubular main body
portion with a distal end and a proximal end with a proximal
inflatable cuff disposed thereon, at least one elongated inflatable
channel in fluid communication with the proximal inflatable cuff,
and a thin flexible layer disposed between the proximal inflatable
cuff and elongated inflatable channel so as to form a conduit to
confine a flow of fluid therethrough; b) a first bifurcated tubular
portion having a distal end and a proximal end which is secured to
the distal end of the main body portion, and having a conduit
therein extending from the proximal end to the distal end, said
conduit in fluid communication with the conduit of the main body
portion; and c) a second bifurcated tubular portion having a distal
end and a proximal end which is secured to the distal end of the
main body portion, and having a conduit therein extending from the
proximal end to the distal end, said conduit in fluid communication
with the conduit of the main body portion.
26. The endovascular graft of claim 25 further comprising an
expansion member secured to the proximal end of the main body
portion and extending proximally therefrom.
27. The endovascular graft of claim 26 wherein the expansion member
is comprised of linked expandable rings.
28. The endovascular graft of claim 27 wherein the linked
expandable rings are comprised of a pseudoelastic shape memory
alloy.
29. The endovascular graft of claim 28 wherein the linked
expandable rings further comprise outward directed
protuberances.
30. The endovascular graft of claim 25 wherein a rupture disc is
disposed between a fluid tight chamber of the proximal inflatable
cuff and a fluid tight chamber of the elongate inflatable
channel.
31. The endovascular graft of claim 30 wherein the first bifurcated
tubular portion further comprises an elongated inflatable channel
in fluid communication with the elongated inflatable channel of the
main body portion and the second bifurcated tubular portion further
comprises an elongated inflatable channel in fluid communication
with the elongated inflatable channel of the main body portion.
32. The endovascular graft of claim 31 further comprising a rupture
disc disposed between the fluid tight chamber of the elongated
inflatable channel of the main body portion and a fluid tight
chamber of the elongated inflatable channel of the first bifurcated
tubular portion.
33. The endovascular graft of claim 32 further comprising a rupture
disc disposed between the fluid tight chamber of the elongated
inflatable channel of the main body portion and a fluid tight
chamber of the elongated inflatable channel of the second
bifurcated tubular portion.
34. The endovascular graft of claim 33 wherein the rupture discs
have different burst thresholds to facilitate sequential deployment
of the graft.
35. The endovascular graft of claim 25 further comprising a
proximal neck portion disposed on the proximal end of the main body
portion.
36. The endovascular graft of claim 35 wherein the proximal neck
portion tapers proximally to a reduced diameter.
37. The endovascular graft of claim 35 wherein the proximal neck
portion tapers proximally to an increased diameter.
38. The endovascular graft of claim 25 wherein the proximal end of
the main body portion further comprises a proximal inlet axis which
forms an inlet axis angle with respect to a longitudinal axis of
the main body portion.
39. The endovascular graft of claim 38 wherein the inlet axis angle
is up to about 50 degrees.
40. The endovascular graft of claim 38 wherein the inlet axis angle
is about 20 to about 30 degrees.
41. The endovascular graft of claim 26 wherein the expansion member
further comprises a proximal inlet axis which forms an inlet axis
angle with respect to a longitudinal axis of the endovascular graft
of about 20 to about 30 degrees.
42. The endovascular graft of claim 26 further comprising elongated
battens disposed upon the graft.
43. The endovascular graft of claim 42 wherein the battens are
comprised of metal or plastic.
44. A method of deploying an endovascular graft comprising: a)
providing an inflatable endovascular graft comprising: a tubular
body member having a proximal end and a distal end; a proximal
inflatable cuff disposed at the proximal end of the tubular body
member; and an expansion member attached to the proximal end of the
tubular member; b) positioning the graft in a desired location
within a body channel of a patient; c) allowing the expansion
member to expand to conform to a morphology of the body channel;
and d) inflating the proximal inflatable cuff of the graft to form
a seal against the body channel.
45. The method of deploying an endovascular graft of claim 44
wherein inflation of the proximal inflatable cuff of the graft
causes the graft and proximal inflatable cuff to conform to a
morphology of the body channel surrounding the graft.
46. The method of claim 44 wherein the endovascular graft is
positioned by percutaneous delivery to a patient's vasculature.
47. The method of claim 44 wherein the expansion member is allowed
to expand by extruding the graft from a constraining tubular
delivery catheter.
48. The method of claim 44 wherein the endovascular graft further
comprises a plurality of inflatable fluid tight chambers which are
separated by rupture discs that are configured to burst at varying
pressure thresholds such that the graft is sequentially
inflated.
49. The method of claim 44 wherein the proximal inflatable cuff is
inflated by injecting a pressurized material through an inflation
catheter and into an injection port which is in fluid communication
with a fluid tight chamber within the proximal inflatable cuff.
50. The method of claim 49 further comprising disconnecting the
inflation catheter from the injection port by applying inflation
pressure sufficient to trigger a disconnect mechanism.
51. A method of manufacturing an endovascular graft comprising a)
forming a tubular member comprising: a tubular body member having a
proximal end and a distal end; a proximal inflatable cuff disposed
at the proximal end of the tubular body member; and b)
thermo-mechanical compaction of the material of the tubular member
in desired areas and make it fluid tight.
52. The method of claim 51 wherein the graft is formed from
ePTFE.
53. An endovascular device comprising: a) a tubular body member
having a proximal end and a distal end; and b) a proximal neck
portion disposed on the proximal end having an inlet axis which
defines an inlet axis angle with respect to a longitudinal axis of
the tubular body member.
54. The endovascular device of claim 53 wherein the inlet axis
angle is up to about 90 degrees.
55. The endovascular device of claim 53 wherein the inlet axis
angle is up to about 60 degrees.
56. The endovascular device of claim 53 wherein the inlet axis
angle is about 15 to about 30 degrees.
57. The endovascular device of claim 53 wherein the inlet axis
angle is about 25 to about 35 degrees.
58. An expansion member configured for use in an endovascular
device comprising a plurality of linked expandable rings.
59. The expansion member of claim 58 wherein the linked expandable
rings are comprised of a superelastic alloy.
60. An endovascular graft comprising: a) an inflatable frame
structure comprising: a main body portion having a proximal end
with a proximal inflatable cuff disposed thereon, a distal end with
a distal inflatable cuff disposed thereon, at least one elongated
inflatable channel disposed between and in fluid communication with
the proximal inflatable cuff and the distal inflatable cuff, a
first bifurcated portion having a proximal end which is connected
to the distal end of the main body portion, a proximal inflatable
cuff disposed on the proximal end, a distal end with a distal
inflatable cuff disposed thereon, at least one elongated inflatable
channel disposed between and in fluid communication with the
proximal inflatable cuff and the distal inflatable cuff, a second
bifurcated portion having a proximal end which is connected to the
distal end of the main body portion, a proximal inflatable cuff
disposed on the proximal end, a distal end with a distal inflatable
cuff disposed thereon, and at least one elongated inflatable
channel disposed between and in fluid communication with the
proximal inflatable cuff and the distal inflatable cuff; and b) a
thin flexible layer member disposed between the proximal inflatable
cuff, the distal inflatable cuff and the elongated inflatable
channel of the main body portion, first bifurcated portion and
second bifurcated portion in order to form a bifurcated tubular
structure having a longitudinal channel to confine a flow of blood
therethrough at each of said portions.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of Provisional
Application Serial No. 60/074,112, filed Feb. 9, 1998. Priority is
hereby claimed to Provisional Application Serial No. 60/074,112,
which also incorporated by reference in its entirety herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a system and method for the
treatment of disorders of the vasculature. More specifically, a
system and method for treatment of abdominal aortic aneurysm and
the like, which is a condition manifested by expansion and
weakening of the aorta below the diaphragm. Such conditions require
intervention due to the severity of the sequelae, which frequently
is death. Prior methods of treating aortic aneurysm have consisted
of invasive surgical methods with graft placement within the aorta
as a reinforcing member of the artery. However, such a procedure
requires a surgical cut down to access the vessel, which in turn
can result in a catastrophic rupture of the aneurysm due to the
decreased external pressure from the organs and tissues surrounding
the aorta, which are moved during the procedure to gain access to
the vessel. Accordingly, surgical procedures have a high mortality
rate due to the possibility of the rupture discussed above in
addition to other factors. Other factors can include poor physical
condition of the patient due to blood loss, anuria, and low blood
pressure associated with the aortic abdominal aneurysm. An example
of a surgical procedure is described in a book entitled Surgical
Treatment of Aortic Aneurysms by Denton A. Cooley, M.D., published
in 1986 by W. B. Saunders Company.
[0003] Due to the inherent risks and complexities of surgical
procedures, various attempts have been made in the development of
alternative methods for deployment of grafts within aortic
aneurysms. One such method is the non-invasive technique of
percutaneous delivery by a catheter-based system. Such a method is
described in Lawrence, Jr. et al. in "Percutaneous endovascular
graft: experimental evaluation", Radiology (May 1987). Lawrence
described therein the use of a Gianturco stent as disclosed in U.S.
Pat. No. 4,580,568. The stent is used to position a Dacron fabric
graft within the vessel. The Dacron graft is compressed within the
catheter and then deployed within the vessel to be treated. A
similar procedure has also been described by Mirich et al. in
"Percutaneously placed endovascular grafts for aortic aneurysms:
feasibility study," Radiology (March 1989). Mirich describes
therein a self-expanding metallic structure covered by a nylon
fabric, with said structure being anchored by barbs at the proximal
and distal ends.
[0004] One of the primary deficiencies of the existing percutaneous
devices and methods has been that the grafts and the delivery
catheters used to deliver the grafts are relatively large in
profile, often up to 24 French and greater, and stiff in bending.
The large profile and bending stiffness makes delivery through the
irregular and tortuous arteries of diseased vessels difficult and
risky. In particular, the iliac arteries are often too narrow or
irregular for the passage of a percutaneous device. Because of
this, non-invasive percutaneous graft delivery for treatment of
aortic aneurysm is not available to many patients who would benefit
from it.
[0005] Another contraindication for current percutaneous grafting
methods and devices is a vessel treatment site with high neck
angulation which precludes a proper fit between the graft and the
vessel wall. An improper fit or seal between the graft and the
vessel wall can result in leaks or areas of high stress imposed
upon the diseased vessel which lead to reduced graft efficacy and
possibly rupture of the aneurysm.
[0006] While the above methods have shown some promise with regard
to treating abdominal aortic aneurysms with non-invasive methods,
there remains a need for an endovascular graft system which can be
deployed percutaneously in a small diameter flexible catheter
system. In addition, there is a need for a graft which conforms
more closely to the contours of an aortic aneurysm which are often
quite irregular and angulated and vary from patient to patient. The
present invention satisfies these and other needs.
SUMMARY OF THE INVENTION
[0007] The present invention is directed generally to an
endovascular graft for vascular treatment and a method for
manufacturing and using the graft. The graft generally has an
inflatable tubular frame structure which can be configured to
conform to the morphology of a patient's vessel to be treated. The
frame structure has a proximal end and a distal end with an
inflatable cuff disposed on at least one end and preferably both.
The inflatable cuffs can be reduced in diameter and profile when
deflated for introduction into a patient's vasculature by a
catheter based delivery system or other suitable means. The
inflatable cuffs provide a sufficiently rigid structure when
inflated which supports the graft and seals the graft against the
interior surface of the vessel in which it is being deployed. One
or more elongated inflatable channels may also be disposed on the
graft. Preferably, the elongated channel is disposed between and in
fluid communication with a proximal and distal inflatable cuff. The
channel provides the desired stiffness upon inflation, prevents
kinking of the graft frame, and facilitates deployment of the graft
within a patient's body passageway. The elongated inflatable
channel can be in a longitudinal or linear configuration with
respect to the graft, but is preferably shaped as a helix disposed
about the graft. Other orientations such as interconnecting grids
or rings may also be suitable for the elongated channels. The
inflatable cuffs and the elongated channel contain fluid tight
chambers which are generally in fluid communication with each other
but which may also be separated by valves or rupture discs therein
to selectively control the sequence of inflation or deployment. The
fluid tight chambers are typically accessed by an injection port
which is configured to accept a pressurized source of gas, fluid,
particles, gel or combination thereof and which is in fluid
communication with at least one of the fluid tight chambers. A
fluid which sets, hardens or gels over time can also be used. The
number of elongated channels can vary with the specific
configuration of the graft as adapted to a given indication, but
generally, the number of channels ranges from 1 to 25, preferably 2
to about 8.
[0008] A proximal neck portion may be secured to the proximal
inflatable cuff. The proximal neck portion has a flexible tubular
structure that has a diameter similar to the proximal inflatable
cuff. The proximal neck portion can be configured as a straight
tubular section or can be tapered distally or proximally to an
increased or decreased diameter. Preferably, the proximal neck
portion is secured and sealed to the proximal inflatable cuff and
tapers proximally to an increased diameter so as to engage the
inside surface of a vessel wall which provides a sealing function
in addition to that of the proximal inflatable cuff. Such a
configuration also smoothes the transition for fluid flow from the
vessel of a patient to the lumen or channel within the endovascular
graft. The proximal neck portion has an inlet axis that preferably
has an angular bias with respect to a longitudinal axis of the
graft.
[0009] Preferably, the graft has a monolithic structure wherein the
material that comprises the inflatable cuffs and channels extends
between these elements in a thin flexible layer that defines a
longitudinal lumen to confine a flow of blood or other fluid
therethrough. Such a monolithic structure can be made from a
variety of suitable polymers including PVC, polyurethane,
polyethylene and fluoropolymers such as TFE, PTFE and ePTFE.
Additional stiffness or reinforcement can be added to the graft by
the addition of metal or plastic inserts or battens to the graft,
which can also facilitate positioning and deployment of the graft
prior to inflation of an inflatable portion of the graft.
[0010] In another embodiment, the graft has a thin flexible layer
disposed over or between a proximal inflatable cuff, a distal
inflatable cuff, and an elongated inflatable channel of the frame.
The thin flexible layer is made of a material differing from the
material of the cuffs or elongated channel. The barrier is shaped
so as to form a tubular structure defining a longitudinal lumen or
channel to confine a flow of blood therethrough. The flexible
barrier may be made of a variety of suitable materials such as
DACRON.RTM., NYLON.RTM., or fluoropolymers such as TEFLON.RTM. or
the like.
[0011] An endovascular graft having features of the invention may
be made in a tubular configuration of a flexible layer material
such as Dacron, Nylon or fluoropolymers as discussed above. The
inflatable cuffs and elongated channels are formed separately and
bonded thereto. The inflatable cuffs and channels may also be made
from the same layer material, i.e., Dacron, Teflon, or Nylon with a
fluid impermeable membrane or bladder disposed within the cuff or
channel so as to make it fluid tight. To limit permeability, the
material in the regions of the cuffs and channels may also be
treated with a coating or otherwise be processed by methods such as
thermo-mechanical compaction.
[0012] In one embodiment of the invention, an expansion member is
attached to the proximal end of the frame structure of the graft or
to a proximal neck portion of the graft. Expansion members may also
be attached to the distal end of the graft. Preferably, the
expansion member is made of an expandable ring or linked expandable
rings of pseudoelastic shape memory alloy which is self expanding
and helps to mechanically anchor the proximal end of the graft to a
body channel to prevent axial displacement of the graft once it is
deployed. By having an expansion member which is distinct from the
proximal cuff, the sealing function of the cuff, which requires
supple conformation to the vessel wall without excessive radial
force, can be separated from the anchoring function of the
expansion member, which can require significant radial force. This
allows each function to be optimized without compromising the
function of the other. It also allows the anchoring function which
can require more radial force on the vessel wall to be located more
proximal from the aneurysm than the cuff, and therefor be
positioned in a healthier portion of the vessel which is better
able to withstand the radial force required for the anchoring
function. In addition, the cuff and expansion members can be
separated spatially in a longitudinal direction with the graft in a
collapsed state for delivery which allows for a lower more flexible
profile for percutaneous delivery. Such a configuration makes a
collapsed delivery profile of 12-16 French possible, preferably
below 12 French.
[0013] The expandable ring or rings of the expansion member may be
formed in a continuous loop having a serpentine or zig-zag pattern
along a circumference of the loop. Any other similar configuration
could be used that would allow radial expansion of the ring. The
expansion member may be made of suitable high strength metals such
as stainless steel, Nitinol or other shape memory alloys, or other
suitable high strength composites or polymers. The expansion member
may be made from high memory materials such as Nitinol or low
memory materials such as stainless steel depending on the
configuration of the endovascular graft, the morphology of the
deployment site, and the mode of delivery and deployment of the
graft.
[0014] The expansion member preferably has an inlet axis which
forms an inlet axis angle in relation to a longitudinal axis of the
graft. The angled inlet axis allows the graft to better conform to
the morphology of a patient's vasculature in patients who have an
angulated neck aneurysm morphology. The inlet axis angle can be
from about 0 to about 90 degrees, preferably about 20 degrees to
about 30 degrees. Some or all of the inlet axis angle can be
achieved in a proximal neck portion of the graft, to which the
expansion member may be attached. An expansion member or members
may also be attached to the distal end of the graft.
[0015] In another embodiment of the invention, the graft may be
bifurcated at the distal end of a main body portion of the graft
and have at least two bifurcated portions with longitudinal lumens
in fluid communication with a longitudinal lumen of the main body
portion. The first bifurcated portion and second bifurcated portion
can be formed from a structure similar to that of the main body
portion with optional inflatable cuffs at either the proximal or
distal end. One or more elongated channels can be disposed between
the inflatable cuffs.
[0016] The size and angular orientation of the bifurcated portions
can vary, however, they are generally configured to have an outer
diameter that is compatible with the inner diameter of a patient's
iliac arteries. The bifurcated portions can also be adapted to use
in a patient's renal arteries or other suitable indication. The
distal ends of the bifurcated portions may also have expansion
members attached thereto in order to anchor or expand, or both
anchor and expand said distal ends within the body passageway being
treated. The expansion members for the distal ends of the
bifurcated portions can have similar structure to the expansion
member attached to the proximal end or proximal neck portion of the
main body portion. The expansion members are preferably made from a
shape memory material such as Nitinol.
[0017] In bifurcated embodiments of grafts having features of the
invention which also have a biased proximal end which forms an
inlet axis angle, the direction of the bias or angulation can be
important with regard to achieving a proper fit between the graft
and the morphology of the deployment site. Generally, the angular
bias of the proximal end of the graft, proximal neck portion or
proximal expansion member can be in any direction. Preferably, the
angular bias is in a direction normal to a plane defined by a
longitudinal axis of the main body portion, the first bifurcated
portion and the second bifurcated portion.
[0018] In another embodiment of the invention, rupture discs or
other temporary closures are placed between fluid tight chambers of
the inflatable cuffs and elongated channel or channels of the graft
and form a seal between the chambers. The rupture discs may be
burst or broken if sufficient force or pressure is exerted on one
side of a disc or temporary closure. Once the graft is located at
the site to be treated within a body passageway of a patient, a
pressurized gas, fluid or gel may be injected by an inflation
catheter into one of the fluid tight chambers of the graft through
an injection port. Injection of a pressurized substance into an
inflatable cuff will cause the cuff to take a generally annular
shape, although the cuff can conform to the shape of the vessel
within which it is deployed, and exert a sufficient radial force
outward against the inner surface of the body passageway to be
treated in order to provide the desired sealing function.
[0019] Multiple rupture discs can be disposed in various locations
of the graft and also be configured to rupture at different
pressures or burst thresholds to facilitate deployment of the graft
within a body passageway. In a particular bifurcated embodiment of
the invention, the proximal inflatable cuff of the main body
portion may be positioned proximal of a junction between the branch
of the abdominal aorta and the iliac arteries of a patient. As the
proximal cuff is deployed by injection of an appropriate substance
into an injection port in fluid communication with the fluid tight
chamber thereof, it will expand radially and become axially and
sealingly fixed proximal to the bifurcation of the aorta. A rupture
disc is located between the fluid tight chamber of the proximal
cuff and the elongated inflatable channels so that the proximal
cuff may be substantially deployed before the rupture disc bursts
and the elongated channels begin to fill with the injected
substance. The elongated channels then fill and become sufficiently
rigid and expand to create a longitudinal lumen therein. As
pressure is increased within the fluid tight chamber, a rupture
disc between the fluid tight chamber of the elongated channels and
a fluid tight chamber of the optional distal inflatable cuff or
distal manifold of the main body portion will burst and the distal
inflatable cuff or manifold will deploy and become pressurized. One
of the bifurcated portions of the graft may then be deployed as a
rupture disc sealing its fluid tight chamber from the distal
inflatable cuff or manifold of the main body portion of the graft
bursts as the inflation pressure is increased. Finally, the second
bifurcated portion of the graft deploys after a rupture disc
sealing its fluid tight chamber from the main body portion
bursts.
[0020] An inflation catheter which is attached to and in fluid
communication with the fluid tight chambers of the graft via an
injection port disposed thereon, can be decoupled from the
injection port after completion of inflation by elevating pressure
above a predetermined level. The elevated pressure causes a break
in a connection with the injection port by triggering a disconnect
mechanism. Alternatively, the inflation catheter can be unscrewed
from its connection. The injection port can include a check valve,
seal or plug to close off the egress of inflation material once the
inflation catheter has been decoupled. The injection port could
also be glued or twisted to seal it off.
[0021] A graft having features of the invention may also be
deployed by percutaneous delivery with a catheter based system
which has an inflatable balloon member disposed within expansion
members of the graft in a collapsed state. The graft is
percutaneously delivered to a desired site. Once the graft is
axially positioned, the inflatable member of the balloon may be
expanded and the expansion members forced radially against the
interior surface of a body channel within which it is disposed. The
expansion members may also be self expanding from a constrained
configuration once the constraint is removed. After the graft has
been positioned by the catheter system, the inflatable cuff or
cuffs and elongated channel or channels of the graft are
pressurized.
[0022] These and other advantages of the invention will become more
apparent from the following detailed description of the invention
when taken in conjunction with the accompanying exemplary
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 shows a perspective view of an endovascular graft
having features of the invention.
[0024] FIG. 2 shows a longitudinal cross sectional view of an
endovascular graft having a monolithic structure.
[0025] FIG. 3 shows an enlarged view of the longitudinal cross
sectional view of the endovascular graft of FIG. 2.
[0026] FIG. 4 shows a longitudinal cross-sectional view of an
endovascular graft having features of the invention.
[0027] FIG. 5 shows an enlarged view of a portion of the
endovascular graft shown in FIG. 4.
[0028] FIG. 6 is a perspective view of a bifurcated endovascular
graft having features of the present invention.
[0029] FIG. 7 is a transverse cross-sectional view of a bifurcated
portion of an endovascular graft taken at 7-7 of FIG. 6.
[0030] FIGS. 8A-8C depict perspective views of a bifurcated
endovascular graft having features of the present invention in
various stages of deployment.
[0031] FIG. 9A is an enlarged longitudinal cross sectional view of
the valve that could be used to maintain inflation of a fluid tight
chamber in the endovascular graft taken at 9-9 of FIG. 8A.
[0032] FIG. 9B is an enlarged longitudinal cross sectional view of
an alternative seal that could be used to maintain inflation of a
fluid tight chamber in the endovascular graft taken at 9-9 of FIG.
8A.
[0033] FIG. 9C is an enlarged longitudinal cross sectional view of
an alternative sealing plug that could be used to maintain
inflation of a fluid tight chamber in the endovascular graft taken
at 9-9 of FIG. 8A.
[0034] FIG. 10 is an enlarged longitudinal cross sectional view of
a rupture disc that could be used to control the inflation sequence
of an inflatable endovascular graft taken at 10-10 of FIG. 8C.
[0035] FIG. 11 is a plot of inflation pressure of an inflatable
endovascular graft with respect to time for an endovascular graft
having features of the present invention including rupture discs
which are configured to yield at various predetermined
pressures.
DETAILED DESCRIPTION OF THE INVENTION
[0036] FIG. 1 shows a perspective view of an endovascular graft 10
having features of the present invention and having a proximal end
11 and a distal end 12. The graft is supported by an inflatable
frame 13 which has a proximal end 14 and a distal end 15 and is
shown in its deployed state. The inflatable frame structure 13 has
a proximal inflatable cuff 16 at the proximal end 14 and an
optional distal inflatable cuff 17 at the distal end 15. The
inflatable cuffs 16 and 17 can be annular in shape when deployed,
although the cuffs can conform to the shape of the vessel within
which they are deployed, and can have an outside diameter or cross
sectional dimension of about 10 to about 45 mm, preferably about 16
to about 28 mm. There is at least one elongated inflatable channel
18 disposed between the proximal inflatable cuff 16 and the distal
inflatable cuff 17. The inflatable frame 13 can be from about 5 to
about 30 cm in length, preferably about 10 to about 20 cm in
length. Disposed between the proximal inflatable cuff 16, the
distal inflatable cuff 17 and the elongated inflatable channel 18
is a thin flexible layer 21 that forms a longitudinal lumen 22
which can confine a flow of fluid therethrough. The thin flexible
layer 21 may be made from the same material as the inflatable cuffs
16 and 17 and elongated channel 18 and be integral with the
construction of those elements forming a monolithic structure. The
thin flexible layer 21 and the materials used to form the frame
structure 13 can have a wall thickness of about 0.1 to about 0.5
mm, preferably about 0.15 to about 0.25 mm. The inflatable frame 13
may be constructed from any suitable medical polymer or other
material, including flouropolymers, PVCs, polyurethanes, PET, ePTFE
and the like. Preferably the inflatable frame 13 and thin flexible
layer 21 are made from ePTFE. A proximal neck portion 23 is
attached to the proximal end of the inflatable frame structure 13
and serves as an additional means to seal the graft against the
inside of a body passageway, provides a means of biasing a proximal
end of the graft 11, and provides a smooth flow transition into
longitudinal lumen 22.
[0037] An expansion member 24 having a proximal end 25 and a distal
end 26 has the distal end secured to the proximal end 14 of the
frame 13. The distal end 26 of the expansion member may also be
secured to the proximal neck portion 23. The expansion member 24
can be made from expandable rings 27 formed in a zig-zag pattern
and connected by links 28. The expansion member 24 is preferably a
self-expanding member that expands to contact the inside wall of a
body passage upon release from a constrained state. The expansion
member 24 may be made from any suitable material that permits
expansion from a constrained state, preferably a shape memory alloy
such as Nitinol. The expansion member 24 may be configured to self
expand from a constrained state or be configured to expand as a
result of an outward radial force applied from within. Other
materials suitable for construction of the expansion member 24
include stainless steel, MP35N alloy, shape memory alloys other
than Nitinol, fiber composites and the like. The links 28 allow
articulation of the expansion member 24 to traverse curvature of a
patient's anatomy both during delivery and in situ. The expansion
member 24 has a generally cylindrical shape but may also have
outwardly directed protuberances 32 that are designed to engage the
inside surface of a body passage. The expansion member 24 is
generally cylindrical in shape when deployed, although the
expansion member can conform to the shape of the vessel within
which it is deployed, and can have a length of about 0.5 to about 5
cm, preferably about 1 to about 4 cm. The diameter of the expansion
member 24 is typically similar to that of the inflatable cuffs 16
and 17, and can be about 10 to about 35 mm, preferably about 16 to
about 28 mm. The high strength material from which the expansion
member 24 is made can have a cross sectional dimension of about 0.1
to about 1.5 mm, preferably about 0.25 to about 1 mm.
[0038] The graft 10 is generally deployed by inflation of the
inflatable frame structure 13 with a pressurized material of solid
particles, gas, fluid or gel which can be injected through an
injection port 33. The pressurized material may contain a contrast
medium which facilitates imaging of the device while being deployed
within a patient's body. For example, radiopaque materials such as
bismuth, barium, gold, platinum, tantalum or the like may be used
in particulate or powder form to facilitate visualization of the
graft under fluoroscopy. Fixed radiopaque markers may also be
attached or integrally molded into the graft for the same purpose,
and may be made from the same radiopaque materials discussed
above.
[0039] FIG. 2 shows a longitudinal cross sectional view of the
endovascular graft shown in FIG. 1. Within the proximal inflatable
cuff 16 is a fluid tight chamber 41 which is in fluid communication
with a fluid tight chamber 42 of the elongated inflatable channel
18. The fluid tight chamber 42 of the elongated inflatable channel
is in fluid communication with a fluid tight chamber 43 within the
optional distal inflatable cuff 17. A longitudinal axis 44 of the
graft 10 is shown in addition to a proximal inlet axis 45 which
forms an inlet axis angle 46 with the longitudinal axis. The angled
inlet axis 45 s generally created by the proximal neck portion 23
and provides the graft with a profile which can conform to the
morphology of a patient's vasculature. The expansion member 24 has
a longitudinal axis 47 which is generally coextensive with the
proximal inlet axis 45, but can further bend to conform to local
anatomy including neck angulation of a diseased vessel.
[0040] FIG. 3 shows an enlarged view of the longitudinal cross
sectional view of a portion of the proximal end 11 of the graft 10
shown in FIG. 2. A more detailed view of the fluid tight chamber 41
of the proximal inflatable cuff 16 can be seen as well as a more
detailed view of the attachment of the distal end 26 of the
expansion member 24 to the proximal neck portion 23. The thin
flexible layer 21 can be seen disposed between the proximal
inflatable cuff 16 and the elongated inflatable channel 18. The
expandable rings 27 of the expansion member 24 are connected by
links 28 which can be made from the same material as the expansion
member or any other suitable material such as a biocompatible fiber
or a metal such as stainless steel or Nitinol.
[0041] FIG. 4 is a transverse cross-sectional view of an embodiment
of an endovascular graft 51, having features of the invention. The
proximal inflatable cuff 52, distal inflatable cuff 53, and
elongated inflatable channel 54 are formed by sealingly bonding
strips of material 55 over a tubular structure 56. The strips 55
are bonded at the edges 57 so as to form fluid tight chambers 58
therein. If the material of the strips 55 which have been bonded to
the tubular structure 56 are of a permeable character, an
additional material may be used to coat the inside of the fluid
tight chambers in order to make them impermeable to fluids.
Alternatively, the material of the strips 55 and the material of
the elongated tubular member 56 adjacent thereto may be made
impermeable by undergoing further thermal, mechanical, or chemical
processing. Preferably, thermo-mechanical compaction would be used
to render the fluid tight chambers 58 impermeable to fluids which
would be suitable for inflating the graft 51.
[0042] The proximal end 61 of the graft 51 has a proximal neck
portion 62 which has an inlet axis 63 which forms an inlet axis
angle 64 with a longitudinal axis 65 of the graft. The inlet axis
angle 64 allows the graft 51 to better conform to a morphology of a
patient's vascular channels. An expansion member 66 is also located
at the proximal end 61 of the graft 51 and is formed of expandable
rings 67 held together by links 68. The expansion member 66 has a
longitudinal axis 71 which can coincide with the inlet axis 63 of
the proximal neck portion 62. The graft 51 has a thin flexible
layer 72 which extends from the distal end 73 of the graft 51, to
the proximal end of the graft 61, including the proximal neck
portion 62. The thin flexible layer 72 forms a longitudinal lumen
or channel 74 upon deployment of the graft, which confines a flow
of blood or other bodily fluid therethrough.
[0043] FIG. 5 is an enlarged view of the longitudinal
cross-sectional view of the endovascular graft of FIG. 4. A more
detailed view of the fluid tight chamber 58 of the proximal
inflatable cuff and elongated inflatable channel can be seen. The
edges of the strips 57 which form the proximal inflatable cuff 52
and the elongated inflatable channel 54 are bonded at the edges by
any suitable technique such as the use of adhesives, solvents, or
heat. Suitable adhesives would include epoxies and cyanoacrylates
or the like. Materials suitable for use as the thin flexible layer
72 or the strips 55 includes Dacron, Nylon, Teflon, and also such
materials as PVC, polyethylene, polyurethane and ePTFE.
[0044] FIGS. 6 and 7 depict an endovascular graft 81 having
features of the invention which has a first bifurcated portion 82
and a second bifurcated portion 83. A main body portion 84 of the
graft 81 has a proximal end 85 and a distal end 86 with a proximal
neck portion 87 disposed at the proximal end as well as an
expansion member 91 which can be formed of expandable rings 92 of a
suitable material which have been linked together. At the distal
end 86 of the main body portion 84 there is an optional distal
inflatable cuff 93 which is connected fluidly to a proximal
inflatable cuff 94 by an elongated inflatable channel 95. The
distal inflatable cuff 93 may optionally be replaced by a manifold
or other suitable structure for fluid connection between the
elongated inflatable channel 95 and the first bifurcated portion 82
or the second bifurcated portion 83.
[0045] The first bifurcated portion 82 has a proximal end 96 and a
distal end 97 with an optional distal inflatable cuff 98 located at
the distal end. The distal end of the first bifurcated portion 97
may have an expansion member in conjunction with or in place of the
distal inflatable cuff 98. The proximal end 96 of the first
bifurcated portion 82 is attached to the distal end 86 of the main
body portion 84 of the graft 81. The first bifurcated portion 82
has an optional inflatable elongated channel 101 which fluidly
connects the distal inflatable cuff 98 of the first bifurcated
portion 82 with the distal inflatable cuff 93 of the main body
portion 84. The inflatable elongated channel 101 also provides
support for first bifurcated portion 82.
[0046] The second bifurcated portion 83 generally has a structure
similar to that of the first bifurcated portion 82, with a proximal
end 102 and a distal end 103. The distal end 103 has an optional
distal inflatable cuff 104. The proximal end 102 of the second
bifurcated portion 83 is connected to the distal end 86 of the main
body portion 84 of the graft 81. The distal end of the second
bifurcated portion 103 may have an expansion member in conjunction
with or in place of the distal inflatable cuff 104. The second
bifurcated portion 83 has an optional inflatable elongated channel
105 which fluidly connects the distal inflatable cuff 104 of the
second bifurcated portion 83 with the distal inflatable cuff 93 of
the main body portion 84. The inflatable elongated channel 105 also
provides support for the second bifurcated portion 83. The
inflatable elongated channel of the first bifurcated portion 101
and inflatable elongated channel of the second bifurcated portion
105 may have a linear configuration as shown, a helical
configuration similar to the main body portion 84, or any other
suitable configuration. Disposed between the proximal inflatable
cuff 94, distal inflatable cuff 93 and elongated inflatable channel
95 of the main body portion 84 of the graft 81 is a thin flexible
layer 106 which forms a longitudinal lumen 107 to confine the flow
of blood or other bodily fluid therethrough. Disposed between the
distal inflatable cuff 98 and the elongated inflatable channel 101
of the first bifurcated portion 82 and the distal inflatable cuff
93 of the main body portion 84 is a first thin flexible layer 108
which forms a longitudinal lumen 109 which is in fluid
communication with the longitudinal lumen 107 of the main body
portion 84. The second bifurcated portion may also be formed
separate of a main body portion and be joined to the main body
portion after percutaneous delivery thereof by docking methods. The
first and second bifurcated portions 82 and 83 are generally
cylindrical in shape when deployed, although they can conform to
the shape of a vessel within which they are deployed, and can have
a length from about 1 to about 10 cm. The outside diameter of the
distal ends of the first and second bifurcated portions 82 and 83
can be from about 2 to about 30 mm, preferably about 5 to about 20
mm.
[0047] A second thin flexible layer 111 is disposed between the
distal inflatable cuff 104 and elongated inflatable channel 105 of
the second bifurcated portion 83 and the distal inflatable cuff 93
of the main body portion 84. The second thin flexible layer 111
forms a longitudinal lumen 112 which is in fluid communication with
the longitudinal lumen 107 of the main body portion 84. The thin
flexible layer of the first bifurcated portion surrounds the
elongated lumen of the first bifurcated portion. The thin flexible
layer of the second bifurcated portion surrounds the elongated
lumen of the second bifurcated portion.
[0048] FIGS. 8A-8C depict an embodiment of an endovascular graft
121 having features of the invention in various stages of
deployment. In FIG. 8A, an inflation catheter 122 is connected to
an injection port 123 in a first bifurcated portion 124 of the
endovascular graft 121. The injection port 123 is connected to a
distal inflatable cuff 125 of the first bifurcated portion 124 and
is in fluid communication with a fluid tight chamber 126 therein.
The first bifurcated portion 124 and a main body portion 127 have
been substantially inflated in FIG. 8A, however, a second
bifurcated portion 128 has been prevented from deployment by
rupture discs 131 which have been disposed within fluid tight
chambers 132 of the elongated inflatable channels 133 of the main
body portion 127 which are connected to fluid tight chambers 134 of
elongated inflatable channels 135 of the second bifurcated portion
128. In FIG. 8B, the second bifurcated portion 128 has been
substantially deployed subsequent to a rupture or bursting of the
rupture discs 131 disposed within the fluid tight chambers 132 and
134 of the elongated inflatable channels 133 and 135 which
permitted the flow of a pressurized substance therein. FIG. 8C
shows the endovascular graft fully deployed and illustrates
detachment of a distal end 136 of the inflation catheter 122 from
the injection port 123 which is carried out by increasing the
pressure within the inflation catheter until a disconnect mechanism
137 is triggered.
[0049] FIG. 9A illustrates a longitudinal cross-sectional view
taken at 9-9 of FIG. 8A. The one-way inflation valve 141 has an
outer wall 142, an inner lumen 143, an annular spring stop 144, an
annular ball seal 145, a sealing body 146 and a sealing spring 147.
The configuration depicted in FIG. 9A allows for the ingress of an
inflation medium in the direction of the arrow 148 while preventing
an egress of same once pressure is removed.
[0050] FIG. 9B illustrates an alternative one way valve. The
one-way inflation valve 149 has an outer wall 149A, an inner lumen
149B, a first reed valve 149C, and a second reed valve 149D which
is fluidly sealed with the first reed valve in a relaxed state. The
configuration depicted in FIG. 9B allows for the ingress of an
inflation medium in the direction of the arrow 149E while
preventing an egress of same once pressure is removed.
[0051] FIG. 9C illustrates an alternative seal 150. The seal has an
outer wall 150A, an inner lumen 150B, a plug 150C and a sealing
surface 150D. The plug 150C has a sealing head 150E which sealingly
engages the sealing surface 150D by irreversible deployment by
application of force to the plug in the direction of the arrow
150F.
[0052] FIG. 10 depicts a longitudinal cross-sectional view of a
rupture disc 151 taken at 10-10 of FIG. 8C. The rupture disc 151
has a wall member 152 which is sealingly secured to the inside
surface 153 of a fluid tight chamber 154. The wall member 152 is
configured to fail under pressure prior to the failure of the
surrounding wall 155 of the fluid tight chamber 154 under pressure.
The rupture disc 151 allows for deployment and inflation of fluid
tight chambers other than those which have been sealed by the
rupture disc. Once sufficient force or pressure is exerted against
the wall 152 of the rupture disc to cause failure, the rupture disc
151 will burst and permit the ingress of an inflation medium and
deployment of a portion of an inflatable graft, previously sealed
by the rupture disc.
[0053] FIG. 11 depicts a graphical representation of inflation
pressure 161 versus the time 162 at an injection port of an
inflatable graft as depicted in FIGS. 8A-8C during the deployment
process. P.sub.1 represents the inflation pressure at the injection
port prior to the rupturing of any rupture discs in the
endovascular graft. P.sub.2 represents the pressure required to
cause failure or bursting of the weakest rupture disc in the
endovascular graft after which a portion of the endovascular graft
previously sealed by the weakest rupture disc is inflated and
deployed. The pressure then increases over time to P.sub.3 which is
the pressure level required to cause failure or bursting of a
second rupture disc. P.sub.4 is the pressure level required for
triggering a disconnect mechanism at the distal end of the
inflation catheter.
[0054] While particular forms of the invention have been
illustrated and described, it will be apparent that various
modifications can be made without departing from the spirit and
scope of the invention. Accordingly, it is not intended that the
invention be limited, except as by the appended claims.
* * * * *