U.S. patent application number 10/438409 was filed with the patent office on 2004-11-18 for sealable attachment of endovascular stent to graft.
This patent application is currently assigned to SCIMED Life Systems, Inc.. Invention is credited to DiMatteo, Kristian, Spiridigliozzi, John, Thistle, Robert C..
Application Number | 20040230289 10/438409 |
Document ID | / |
Family ID | 33417568 |
Filed Date | 2004-11-18 |
United States Patent
Application |
20040230289 |
Kind Code |
A1 |
DiMatteo, Kristian ; et
al. |
November 18, 2004 |
Sealable attachment of endovascular stent to graft
Abstract
An endovascular prosthesis of the present invention includes an
expandable stent and a means for sealably attaching a tubular graft
to the stent within the stent's lumen. The means of sealably
attaching a graft includes membranes, foams, polymeric materials
and combinations thereof. Additionally, the present invention
includes methods of forming an endovascular prosthesis and methods
of implanting an endovascular prosthesis within a vessel to provide
sealable securement of a tubular graft within the stent's
lumen.
Inventors: |
DiMatteo, Kristian;
(Waltham, MA) ; Spiridigliozzi, John; (Sharon,
MA) ; Thistle, Robert C.; (Bridgewater, MA) |
Correspondence
Address: |
HOFFMANN & BARON, LLP
6900 JERICHO TURNPIKE
SYOSSET
NY
11791
US
|
Assignee: |
SCIMED Life Systems, Inc.
|
Family ID: |
33417568 |
Appl. No.: |
10/438409 |
Filed: |
May 15, 2003 |
Current U.S.
Class: |
623/1.13 |
Current CPC
Class: |
A61F 2/07 20130101; A61F
2/90 20130101; A61F 2220/005 20130101; A61F 2220/0058 20130101;
A61F 2220/0075 20130101; A61F 2002/065 20130101; A61F 2002/075
20130101 |
Class at
Publication: |
623/001.13 |
International
Class: |
A61F 002/06 |
Claims
What is claimed is:
1. An endovascular prosthesis comprising: (a) an expandable stent
having a distal end, a proximal end and an inner lumen; and (b) a
membrane supported by said stent and extending across said lumen,
said membrane including a graft receiving member for sealably
receiving at least one tubular graft therethrough.
2. An endovascular prosthesis of claim 1, wherein said graft
receiving member comprises a slit.
3. An endovascular prosthesis of claim 2, wherein said graft
receiving member is electrostatically spun material.
4. An endovascular prosthesis of claim 1, wherein said graft
receiving member comprises a valve.
5. An endovascular prosthesis of claim 1, wherein said graft
receiving member comprises a weakened section.
6. An endovascular prosthesis of claim 1, wherein said graft
receiving member comprises a penetrable material.
7. An endovascular prosthesis of claim 1, further comprising a
second graft receiving member.
8. In combination, an endovascular prosthesis of claim 1, and a
tubular graft extending sealably through said graft receiving
member.
9. The combination of claim 8, wherein said tubular graft has an
interior surface and exterior surface, and an expandable foam on
said exterior surface, said foam being expandable within said graft
receiving member, sealably securing said tubular graft to said
graft receiving member.
10. An endovascular prosthesis of claim 8, further comprising a
polymeric material sealably securing said tubular graft to said
membrane.
11. A method of forming an endovascular prosthesis comprising the
steps of: a. providing an expandable stent defining a lumen therein
comprising distal end and a proximal end; b. providing a membrane
including a graft receiving member for sealably receiving at least
one tubular graft therethrough; and c. attaching said membrane to
said stent, wherein said membrane extends across said lumen and is
supported thereby.
12. A method of implanting an endovascular prosthesis within a
vessel comprising: a. providing, in a compressed first diameter, a
radially expandable stent having a distal end, a proximal end and
an inner lumen; and a membrane supported by said stent and
extending across said lumen, said membrane including a graft
receiving member for sealably receiving at least one tubular graft
therethrough; b. delivering said stent within a vessel to an area
of implantation; and c. permitting said stent to radially expand to
a second diameter; and thereby engage a vessel wall.
13. A bifurcated endovascular prosthesis comprising: (a) a first
prosthetic component comprising: (i) an expandable stent having a
distal end, a proximal end and an inner lumen; and (ii) a membrane
extending transversely across said inner lumen and attached to said
stent, said membrane having an opening; and (b) a second prosthetic
component extending into said opening in a substantially fluid
tight seal, said second component comprising a branched graft.
14. A bifurcated endovascular prosthesis of claim 13, wherein said
membrane has a first opening and a second opening.
15. A bifurcated endovascular prosthesis of claim 14, wherein said
branched graft comprises a first graft extending into said first
opening, and a second graft extending into said second opening in a
substantially fluid-tight seal.
16. A bifurcated endovascular prosthesis of claim 15, wherein said
membrane comprises polyurethane, polyethylene,
polytetrafluoroethylene, and combinations thereof.
17. A bifurcated endovascular prosthesis of claim 15, wherein said
first opening and second opening each comprises a valve.
18. A bifurcated endovascular prosthesis of claim 15, wherein said
first prosthetic component is adapted to reside in an aortic
artery, and said first graft and second graft are each adapted to
respectively reside in separate iliac arteries.
19. A method of forming a bifurcated endovascular prosthesis
comprising the steps of: a. providing a first prosthetic component
comprising: (i) an expandable stent having a distal end, a proximal
end and an inner lumen; and (ii) a membrane extending transversely
across said inner lumen and attached to said stent, said membrane
having an opening; b. providing a second prosthetic component
comprising a branched graft; and c. extending said second
prosthetic component into said opening of said membrane, wherein
said membrane forms a substantially fluid tight seal with said
second component.
20. A method of implanting a bifurcated endovascular prosthesis
within a vessel comprising: a. providing, in a compressed first
diameter, a first prosthetic component comprising an expandable
stent having a distal end, a proximal end and an inner lumen; and a
membrane extending transversely across said inner lumen and
attached to said stent, said membrane having an opening; b.
providing a second prosthetic component comprising a branched
graft; c. delivering said first prosthetic component within a
vessel to an area of implantation; d. permitting said first
prosthetic component to radially expand to a second diameter; and
thereby engage a vessel wall; and e. delivering said second
prosthetic component within said opening of said stent forming a
substantially fluid tight seal between said membrane and said
second prosthetic component.
21. A method of forming a bifurcated endovascular prosthesis
comprising the steps of: a. providing a prosthetic component
comprising: (i) an expandable stent having a distal end, a proximal
end and an inner lumen; and (ii) a membrane extending transversely
across said inner lumen and attached to said stent, said membrane
having a first opening and a second opening; b. providing a first
graft having a first inner surface, a first outer surface defining
a first interior lumen; c. providing a second graft having a second
inner surface, a second outer surface defining a second interior
lumen; d. extending said first graft into said first opening of
said membrane, wherein said membrane forms a substantially fluid
tight seal between said prosthetic component and said first graft;
and e. extending said second graft into said second opening of said
membrane, wherein said membrane forms a substantially fluid tight
seal between said prosthetic component and said second graft.
22. A method of implanting a bifurcated endovascular prosthesis
within a vessel comprising: a. providing, in a compressed first
diameter, a prosthetic component comprising an expandable stent
having a distal end, a proximal end and an inner lumen; and a
membrane extending transversely across said inner lumen and
attached to said stent, said membrane having an opening; b.
providing a first graft having a first inner surface, a first outer
surface defining a first interior lumen; c. providing a second
graft having a second inner surface, a second outer surface
defining a second interior lumen; d. delivering said prosthetic
component within a vessel to an area of implantation; e. permitting
said prosthetic component to radially expand to a second diameter;
and thereby engage a vessel wall; f. delivering said first graft
within said opening of said stent forming a substantially fluid
tight seal between said membrane and said first graft; and g.
delivering said second graft within said opening of said stent
forming a substantially fluid tight seal between said membrane and
said second graft.
23. An endovascular prosthesis comprising: (a) an expandable stent
having an inner lumen, a first end and a second end; and (b) a
membrane attached to said stent extending transversely across said
lumen, said membrane comprising electrostatically spun material
having a graft receiving opening for sealably receiving at least
one tubular graft therethrough.
24. In combination, an endovascular prosthesis of claim 23, and at
least one tubular prosthesis extending through said graft receiving
opening and sealably supporting said at least one tubular
prosthesis.
25. A method of forming an endovascular prosthesis comprising the
steps of: a. providing an expandable stent having an inner lumen, a
first end and a second end; b. providing a membrane comprising
electrostatically spun material having a graft receiving opening
for sealably receiving at least one tubular graft therethrough; and
c. attaching said membrane to said stent, wherein said membrane
extends transversely across said lumen and is supported
thereby.
26. A method of implanting an endovascular prosthesis within a
vessel comprising: a. providing, in a compressed first diameter, an
expandable stent having a first end, a second end and an inner
lumen; and a membrane comprising electrostatically spun material
supported by said stent and extending across said lumen, said
membrane including a graft receiving opening for sealably receiving
at least one tubular graft therethrough; b. delivering said stent
within a vessel to an area of implantation; and c. permitting said
stent to radially expand to a second diameter; and thereby engage a
vessel wall.
27. A multi-component endovascular prosthetic system comprising:
(a) a first expandable prosthesis comprising: (i) a first
expandable stent having a distal end, a proximal end and an inner
lumen; and (ii) a first membrane extending transversely across said
inner lumen and attached to said first stent, said first membrane
having a first graft receiving opening; (b) a second expandable
prosthesis spaced from said first prosthesis comprising: (i) a
second expandable stent having a distal end, a proximal end and an
inner lumen; and (ii) a second membrane extending transversely
across said inner lumen and attached to said second stent, said
second membrane having a second graft receiving opening; and (c) a
tubular graft extending sealably through said first graft receiving
opening and said second graft receiving opening for directing fluid
through said tubular graft.
28. A multi-component endovascular prosthetic system of claim 27,
wherein said tubular graft has a porous portion disposed between
said first expandable prosthesis and said second expandable
prosthesis to allow for fluid flow through said porous portion.
29. A multi-component endovascular prosthetic system of claim 28,
wherein said porous portion comprises a stent.
30. A multi-component endovascular prosthetic system of claim 28,
wherein said porous portion comprises slits.
31. A multi-component endovascular prosthetic system of claim 28,
wherein said porous portion comprises fluid permeable material.
32. A multi-component endovascular prosthetic system of claim 27,
wherein said first membrane has a pair of first graft receiving
openings, said graft receiving openings each receiving a tubular
graft therethrough.
33. A multi-component endovascular prosthetic system of claim 32,
wherein said first membrane has a fluid flow opening.
34. A multi-component endovascular prosthetic system of claim 33,
wherein said second membrane has a pair of second graft receiving
openings, said second graft receiving openings each receiving a
tubular graft therethrough.
35. A method of forming a multi-component endovascular prosthesis
comprising the steps of: a. providing a first expandable prosthesis
comprising: (i) a first expandable stent having a distal end, a
proximal end and an inner lumen; and (ii) a first membrane
extending transversely across said inner lumen and attached to said
first stent, said first membrane having a first graft receiving
opening; b. providing a second expandable prosthesis spaced from
said first prosthesis comprising: (i) a second expandable stent
having a distal end, a proximal end and an inner lumen; and (ii) a
second membrane extending transversely across said inner lumen and
attached to said second stent, said second membrane having a second
graft receiving opening; and c. providing a tubular graft having an
outer surface, and an inner surface defining an inner lumen; and d.
extending said tubular graft through said first graft receiving
opening and said second graft receiving opening for directing fluid
through.
36. A method of implanting a multi-component endovascular
prosthesis within a vessel comprising: a. providing, in a
compressed first diameter, a first expandable prosthesis comprising
a first expandable stent having a distal end, a proximal end and an
inner lumen; and a first membrane extending transversely across
said inner lumen and attached to said first stent, said first
membrane having a first receiving opening; b. providing, in a
compressed second diameter, a second expandable prosthesis
comprising a second expandable stent having a distal end, a
proximal end and an inner lumen; and a second membrane extending
transversely across said inner lumen and attached to said second
stent, said second membrane having a second receiving opening; c.
providing a tubular graft having an outer surface, and an inner
surface defining a graft inner lumen; d. delivering said first
expandable prosthesis within a vessel to an area of implantation;
e. permitting said first expandable prosthesis to radially expand
to a third diameter; and thereby engage a vessel wall; f.
delivering said second expandable prosthesis spaced from said first
expandable prosthesis within a vessel to an area of implantation;
g. permitting said second expandable prosthesis to radially expand
to a fourth diameter; and thereby engage a vessel wall; h.
delivering said tubular graft within said first receiving opening
and said second receiving opening forming a substantially fluid
tight seal between said first membrane and said tubular graft, and
said second membrane and said tubular graft.
37. An endovascular prosthesis comprising: (a) a stent having an
inner lumen, a distal end and a proximal end, said distal end
having an opening, and said proximal end having two openings
opposing said distal opening; and (b) a puncturable membrane
extending across each of said proximal end openings.
38. In combination, an endovascular prosthesis of claim 37, and at
least one tubular graft extending through said distal end opening
and puncturably through one of said membranes at said proximal end,
thereby forming a fluid seal between said tubular graft and said
stent at said proximal end.
39. The combination of claim 38, further comprising a pair of
tubular grafts extending through said distal end, with one tubular
graft extending puncturably through each membrane at said proximal
end of said stent to thereby form a fluid seal between said tubular
graft and said stent at said proximal end.
40. A method of forming an endovascular prosthesis comprising the
steps of: a. providing an expandable stent having an inner lumen, a
distal end and a proximal end, wherein said distal end having an
opening and said proximal end having two openings opposing said
distal opening; b. providing a puncturable membrane; and c.
attaching said membrane to said stent transversely across each of
said proximal end openings.
41. A method of implanting an endovascular prosthesis within a
vessel comprising: a. providing, in a compressed first diameter, an
expandable stent having a distal end, a proximal end and an inner
lumen, wherein said distal end having an opening and said proximal
end having two openings opposing said distal opening; and a
puncturable membrane supported by said stent and extending across
said lumen; b. delivering said stent within a vessel to an area of
implantation; and c. permitting said stent to radially expand to a
second diameter; and thereby engage a vessel wall.
42. An endovascular prosthesis comprising: (a) an expandable stent
having a distal end, a proximal end, and an opening extending
therethrough; (b) a first graft attached to said distal end of said
stent within said opening, and having an inner lumen extending
therethrough; (c) a second graft attached to said proximal end of
said stent within said opening and spaced from said first graft,
said second graft having at least two inner lumens extending
therethrough; and (d) a membrane extending transversely across each
of said inner lumens of said second graft.
43. In combination, an endovascular prosthesis of claim 42, and at
least two tubular prosthesis, one of such prosthesis extending
puncturably through each of said respective membranes.
44. A method of forming an endovascular prosthesis comprising the
steps of: a. providing an expandable stent having a distal end and
a proximal end, and an opening extending therethrough; b. providing
a first graft having an inner lumen extending therethrough; c.
providing a second graft having at least two inner lumens extending
therethrough; d. providing a membrane; e. attaching said first
graft to said distal end of said stent within said opening; f.
attaching said second graft to said proximal end of said stent
within said opening and spaced from said first graft; and g.
attaching said membrane transversely across each of said inner
lumens of said second graft.
45. A method of implanting an endovascular prosthesis within a
vessel comprising: a. providing, in a compressed first diameter, an
expandable stent having a distal end, a proximal end and an opening
therethrough, said stent comprising a first graft attached to said
distal end of said stent within said opening, and having an inner
lumen extending therethrough; a second graft attached to said
proximal end of said stent within said opening and spaced from said
first graft, said second graft having at least two inner lumens
extending therethrough; and a membrane extending transversely
across each of said inner lumens of said second graft; b.
delivering said stent within a vessel to an area of implantation;
and c. permitting said stent to radially expand to a second
diameter; and thereby engage a vessel wall.
46. An endovascular prosthetic assembly comprising: (a) an
expandable stent having a distal end, a proximal end and an inner
lumen having an inner surface and an outer surface; (b) a tubular
graft inserted within said inner lumen, said tubular graft having
an interior surface and exterior surface; and (c) an expanded foam
attached to said exterior surface of said graft, said expanded foam
sealably securing said tubular graft to said stent.
47. An endovascular prosthesis of claim 46, wherein said expanded
foam is adhesively bonded to said exterior surface of said
graft.
48. An endovascular prosthesis of claim 46, wherein said expanded
foam is mechanically fastened to said exterior surface of said
graft.
49. An endovascular prosthesis of claim 46, further comprising a
second tubular graft inserted within said inner lumen, said second
tubular graft having a second interior surface and a second
exterior surface, and a second expanded foam bonded to said second
exterior surface, said second expanded foam sealably securing said
second tubular graft to said stent.
50. A kit of parts for assembly into an endovascular prosthetic
system, comprising: (a) an expandable stent having a distal end, a
proximal end and an inner lumen for insertion into a body
endovascularly; (b) a tubular graft adapted to be inserted within
said inner lumen, said tubular graft having an interior surface for
body fluid flow and an exterior surface; and (c) an expandable foam
on said exterior surface of said tubular graft, said expandable
foam adapted to expand within said stent to sealably secure said
tubular graft to said stent.
51. A method of forming an endovascular prosthesis comprising the
steps of: a. providing an expandable stent having a distal end, a
proximal end and an inner lumen having an inner surface and an
outer surface; b. providing a tubular graft having an interior
surface and exterior surface; c. providing an expandable foam; d.
attaching said expandable foam to said exterior surface of said
graft; e. inserting said tubular graft within said inner lumen of
said stent, wherein said expandable foam is in a compressed state;
and f. allowing said expandable foam to expand within said stent
and sealably securing said tubular graft within said stent.
52. A method of implanting an endovascular prosthesis within a
vessel comprising: a. providing, in a compressed first diameter, an
expandable stent having a distal end, a proximal end, an inner
surface, an outer surface and an inner lumen; b. providing a
tubular graft having an interior surface and an exterior surface,
said tubular graft having, in a compressed second diameter, an
expandable foam attached to said exterior surface of said graft; c.
delivering said stent within a vessel to an area of implantation;
d. permitting said stent to radially expand to a third diameter;
and thereby engage a vessel wall; e. delivering said graft within
said inner lumen of said stent; and f. permitting said foam of said
graft to expand to a fourth diameter, thereby sealably securing
said graft to said stent.
53. An endovascular prosthetic assembly comprising: (a) a stent
having an inner surface and an outer surface; (b) a tubular graft
extending within said inner lumen, said tubular graft having an
interior surface and an exterior surface, and an opening
therethrough; and (c) a polymeric material sealably supporting said
tubular graft to said stent.
54. An endovascular prosthetic assembly of claim 53 wherein said
polymeric material is a hydrogel.
55. An endovascular prosthesis of claim 53, further comprising a
second tubular graft extending within said inner lumen, said second
tubular graft having an interior surface and an exterior surface,
and an opening therethrough; and said polymeric material sealably
supporting said second tubular graft to said stent.
56. A kit of parts for assembly into an endovascular prosthetic
system comprising: (a) a stent having an inner surface, an outer
surface and an inner lumen, a primary reactive material being
disposed on said inner surface; (b) a tubular graft adapted to
extend within said inner lumen, said graft having an interior
surface and an exterior surface, said primary material being
disposed on said exterior surface; and (c) a secondary material
reactive with said primary material and adapted to be applied to
said primary material upon insertion of said graft within said
inner lumen, said secondary material being reactive with said
primary material to form a seal between said graft and said
stent.
57. A method of forming an endovascular prosthesis comprising the
steps of: a. providing a stent having an inner surface, an outer
surface and an inner lumen; b. providing a tubular graft having an
interior surface and an exterior surface, and an opening
therethrough; c. providing a primary material; d. providing a
secondary material reactive with said primary material; b.
disposing said primary material on said inner surface of said
stent; e. disposing said primary material on said exterior surface
of said tubular graft; f. inserting said tubular graft within said
inner lumen of said stent; and g. introducing said secondary
material into said inner lumen of said stent, wherein said
secondary material react with said primary material defining a
polymeric material sealably supporting said tubular graft to said
stent.
58. A method of implanting an endovascular prosthesis within a
vessel comprising: a. providing, in a compressed first diameter, an
expandable stent having an inner surface, an outer surface and an
inner lumen therethrough, said inner surface of said stent having a
primary material disposed about said surface; b. providing a
tubular graft having an interior surface and an exterior surface,
said exterior surface of said graft having a primary material
disposed about said surface; c. providing a secondary material
reactive with said primary material; d. delivering said stent
within a vessel to an area of implantation; e. permitting said
stent to radially expand to a second diameter; and thereby engage a
vessel wall; f. delivering said graft within said inner lumen of
said stent; g. delivering said second material into said inner
lumen of said stent; and h. permitting said secondary material to
react with said primary material defining a polymeric material
sealably supporting said tubular graft to said stent.
59. An endovascular prosthesis comprising: (a) an expandable stent
having a distal end, a proximal end and an inner lumen; and (b)
means for sealably attaching a tubular graft to said stent within
said lumen.
60. An endovascular prosthesis of claim 59, wherein said means
comprises a membrane supported by said stent and extending across
said lumen, said membrane including a graft receiving member for
sealably receiving at least one tubular graft therethrough.
61. An endovascular prosthesis of claim 59, wherein said means
comprises an expandable foam bonded to said tubular graft.
62. An endovascular prosthesis of claim 59, wherein said means
comprises a polymeric material, said polymeric material comprising
the reaction product of a primary material on said inner lumen of
said stent and on said tubular graft, and a secondary material
thereby forming a sealed attachment between said tubular graft and
said stent.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an endovascular prosthesis
for intraluminal delivery, and a method of implanting the
endovascular prosthesis for repairing an aorta. More particularly,
the present invention relates to endovascular prosthesis including
a stent and a means for sealably attaching a graft thereto for use
in a blood vessel or a bifurcated system, such as an abdominal
aortic artery where it bifurcates to the common iliac arteries.
BACKGROUND OF THE INVENTION
[0002] An abdominal aortic aneurysm ("AAA") is an abnormal dilation
of the arterial wall of the aorta in the region of the aorta that
passes through the abdominal cavity. The condition most commonly
results from atherosclerotic disease. Abdominal aortic aneurysms
are typically dissecting aneurysms, which are aneurysms that are
formed when there is a tear or fissure in the arterial lining or
wall through which blood is forced and eventually clots, forming a
thrombosis which swells and weakens the vessel. Abdominal aortic
aneurysms typically do not cause pain and are easily detected by
physical examination. The aneurysm may rupture if it is not
detected and treated, causing massive hemorrhaging which is likely
to be fatal to the patient.
[0003] Treatment of AAAs typically comprises some form of arterial
reconstructive surgery, commonly referred to as a "triple-A"
procedure. One such method is bypass surgery, in which an incision
is made into the abdominal cavity, the aorta is closed off above
and below the site of the aneurysm, the aneurysm is resected, and a
synthetic graft or tube sized to approximate the diameter of the
normal aorta is sutured to the vessel to replace the aneurysm and
to allow blood flow through the aorta to be reestablished.
[0004] Many patients experiencing such AAAs, however, are over 65
years of age and often have other chronic illnesses which increase
the risk of pre-operative or post-operative complications. Thus,
such patients are not ideal candidates for triple-A procedures.
Further, this procedure is generally not performed successfully
once an aneurysm has ruptured due to the extensiveness of the
surgery and the time required to prepare a patient for surgery. The
mortality rate for patient experiencing such ruptured aneurysms is
over 65%.
[0005] As a result of the aforementioned disadvantages to
conventional surgical methods, minimally invasive techniques have
been developed for the repair of AAAs. Such methods involve
placement of a stent-graft at the site of the aneurysm by a
catheter, known as an introducer, which serves as a deployment
device. The stent-graft and its deployment system are typically
introduced into the blood stream percutaneously and negotiated by
means of a guidewire to the site of the aneurysm where the stent is
caused to be radially expanded. Such procedures are desirable as
they can be performed using local anesthesia and do not expose the
patient to many of the same risks associated with triple-A
procedures. But the bifurcated structure and environment of the
abdominal aortic and the technology of the prior art stent-grafts
continue to be plagued with issues associated with long term
stability.
[0006] In such minimally invasive repair procedures, the bifurcated
structure of the abdominal aortic arch necessitates the use of a
uniquely-structured bifurcated stent-graft. Typically, aneurysms,
occlusions or stenoses will occur at the location where the aortic
arch bifurcates into the iliac arteries and may also occur at the
iliac arteries. The in situ positioning of stent-grafts in this
area is more difficult than the positioning of such devices in the
lumen of non-bifurcated vessels. As both limbs of a bifurcated
stent-graft are inserted and advanced through a single branch of
the femoral arterial system, one of the limbs of the stent-graft
must ultimately be pulled or drawn into the contralateral branch so
that the stent-graft is suitably positioned across both the aortic
aneurysm and the associated common iliac aneurysms to supply
circulation to each of the lower limbs.
[0007] Bifurcated stent-grafts are frequently too bulky to advance
through a single iliac artery, particularly in view of the fact
that the limb for the contralateral branch of the stent-graft must
be inserted together with the limb of the ipsilateral branch.
Additionally, care must be taken to not twist or kink the
stent-graft as it is placed in the contralateral artery. The caudal
portion of the graft must not stretch across the mouth of the
internal iliac artery which would result in inadvertent occlusion
of that artery. The procedure of drawing one limb of the
stent-graft from one femoral artery to the contralateral femoral
artery requires placement of a cross-femoral catheter using a
closable wire basket prior to insertion of the stent-graft.
[0008] This procedure requires significant and skillful wire
catheter manipulation, frequently within the aneurysmal cavity. As
such, care must be taken to avoid disturbing or dislodging thrombic
or embolic material from within the aneurysmal sac. Additional
factors such as the severe tortuosity of the iliac arteries and the
marked angulation of the aortoiliac junction resulting from the
tendency of the abdominal aortic artery to extend caudally during
aneurysm formation combine to make deployment of endoluminal
bifurcated grafts time consuming and at increased risk of
procedural complications and failure.
[0009] To overcome the aforementioned risks associated with the use
of one-piece stent-grafts in the repair of aneurysms occurring in
bifurcated vessels, two component bifurcated designs have been
developed which may be assembled in situ. The first component
consists of the upper trunk, which is positioned just below the
renals, a stump, and an iliac limb. The second component is then
deployed into the stump, connecting the device to the contralateral
iliac limb. These devices have had a number of issues, which
include fabric wear, kinking, and endoleaks at the upper neck and
at the stump junction; in addition, some have proven to be
difficult to manufacture, not secure to vessel wall, or difficult
to assemble in situ.
[0010] The main reason for lack of success with endoluminal repair
focuses around the fact that the vascular system in general, and
more apparent in an aneurysm sac is the morphology continues to
change. The morphological environment leads to unexpected and
unanticipated stress which is placed on the stent-grafts used to
treat the disease. Such wearing and endoleaking necessitates the
repair of these devices, requiring additional surgical procedures
which may include replacement of the device. Consequently, there is
a continuing need for the development of stents with attached
grafts and techniques useful for the repair of aneurysms in
general, and AAAs.
SUMMARY OF THE INVENTION
[0011] In view of the foregoing, it is an object of the present
invention to provide an endovascular prosthesis and method of
implanting the prosthesis into a vessel that provides a means for
sealably attaching a tubular graft within the endovascular
prosthesis. Additionally, the present invention provides for a
prosthesis that is flexible and durable to adjust to the
morphological environment and is able to assemble in situ.
[0012] The present invention includes an endovascular prosthesis
including an expandable stent having an inner lumen, and a means
for sealably attaching a tubular graft within the lumen of the
stent. The means of sealably attaching a graft includes membranes,
foams, polymeric materials and combinations thereof.
[0013] Another embodiment of the present invention, there is
provided an endovascular prosthesis including an expandable stent
and a membrane supported by the stent and extending across the
lumen. The membrane further including a graft receiving member for
sealably receiving at least one tubular graft therethrough.
[0014] The present invention further provides an endovascular
prosthesis as above-described and the membrane further including an
electrostatically spun material having a graft receiving opening
for sealably receiving at least one tubular graft therethrough.
[0015] An embodiment of the present invention, there is provided a
bifurcated endovascular prosthesis including a first prosthetic
component and a second component. The first component is similar to
those described-above including a stent, a membrane extending
transversely across the inner lumen of the stent and attached
thereto. The membrane additionally having an opening. The second
prosthetic component being extended through the opening in a
substantially fluid tight seal. The second component further
including one or more grafts.
[0016] A further embodiment of the present invention, there is
provided a multi-component endovascular prosthetic system including
two prosthesis and a tubular graft. Each prosthesis including an
expandable stent and a membrane extending transversely across the
inner lumen and attached to the stent. Each membrane further having
a graft receiving opening. The tubular graft being extended
sealably through a graft receiving opening of each prosthesis for
directing fluid through the tubular graft.
[0017] Another embodiment of the present invention, there is
provided an endovascular prosthesis including a stent having an
inner lumen, a distal end and a proximal end, the distal end having
an opening, and the proximal end having two openings opposing the
distal opening; and a puncturable membrane extending across each of
the proximal end openings.
[0018] Another aspect of the present invention, there is provided
an endovascular prosthesis including an expandable stent, a first
graft and a second graft. The expandable stent has a distal end and
a proximal end, and an opening extending therethrough. The first
graft being attached to the distal end of the stent within the
opening, and having an inner lumen extending therethrough. The
second graft being attached to the proximal end of the stent within
the opening and spaced from the first graft. The second graft
having at least two inner lumens extending therethrough and a
membrane extending transversely across each of the inner lumens of
the second graft.
[0019] Another embodiment of the present invention, there is
provided an endovascular prosthetic assembly including an
expandable stent and a tubular graft inserted within the inner
lumen of the stent. The graft having an expanded foam attached to
the exterior surface of the graft. The expandable foam sealably
securing the tubular graft to the stent.
[0020] One aspect of the present invention, there is provided a kit
of parts for assembly into an endovascular prosthetic system. The
kit including an expandable stent for insertion into a body
endovascularly; a tubular graft adapted to be inserted within the
stent, the tubular graft having an interior surface for body fluid
flow and an exterior surface; and an expandable foam on the
exterior surface of the tubular graft. The expandable foam being
adapted to expand within the stent to sealably secure the tubular
graft to the stent.
[0021] A further embodiment of the present invention, there is
provided an endovascular prosthetic assembly including a stent, a
tubular graft extending into the stent and a polymeric material
sealably supporting the tubular graft to the stent.
[0022] Another aspect of the present invention there is provided, a
kit of parts for assembly into an endovascular prosthetic system.
The kit including a stent having a primary reactive material being
disposed on the inner surface of the stent; a tubular graft adapted
to extend within the inner lumen, the graft having the primary
material being disposed on the exterior surface; and a secondary
material reactive with the primary material. The second material
being adapted to be applied to the primary material upon insertion
of the graft within the inner lumen, the secondary material being
reactive with the primary material to form a seal between the graft
and the stent.
[0023] A further aspect of the present invention there is provided
methods of forming and methods of implanting the various
endovascular prosthesis of the present invention within a
vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is an enlarged plan view of the endovascular
prosthesis of the present invention including a stent and attached
membrane having graft receiving members.
[0025] FIG. 2 is a plan view of an endovascular prosthesis of FIG.
1 implanted in abdominal aorta.
[0026] FIG. 3 is a top view of the endovascular prosthesis of FIG.
1 showing the graft receiving members.
[0027] FIG. 4 shows the endovascular prosthesis of FIG. 1 further
including grafts.
[0028] FIG. 5 is a top view of the endovascular prosthesis of FIG.
3 including grafts therethrough.
[0029] FIG. 6 shows the bifurcated endovascular prosthesis of FIG.
2 including a branched graft.
[0030] FIG. 7 shows the endovascular prosthesis of FIG. 2 including
tubular prosthesis for a bifurcated system.
[0031] FIG. 8 shows the endovascular prosthesis of FIG. 7 showing a
deployment of tubular prosthesis for a bifurcated system.
[0032] FIG. 9 is a plan view of an endovascular prosthesis of the
present invention showing a stent and a membrane.
[0033] FIG. 10 shows the endovascular prosthesis of FIG. 9 further
including tubular graft.
[0034] FIG. 11 shows a multi-component endovascular prosthetic
system of the present invention.
[0035] FIG. 12 shows an endovascular prosthesis of the present
invention combined with tubular grafts.
[0036] FIG. 13 is an enlarged plan view of an endovascular
prosthesis of FIG. 12 including a stent and attached membrane.
[0037] FIG. 14 is a plan view of an endovascular prosthesis of the
present invention showing a stent, grafts and membranes in
combination with tubular grafts.
[0038] FIG. 15 is a plan view of the endovascular prosthesis system
of the present invention showing the expandable foam in the
expanded state.
[0039] FIG. 16 shows the endovascular prosthetic assembly of FIG.
15 showing the expandable foam.
[0040] FIG. 17 is a plan view of an endovascular prosthesis of the
present invention showing a stent having an attached membrane in
combination with an expandable foam.
[0041] FIG. 18 is a plan view of an endovascular prosthetic system
of the present invention showing a polymeric material sealably
supporting a tubular graft to a stent.
[0042] FIG. 19 shows the endovascular prosthetic system of FIG. 18
showing a primary reactive material on a graft and stent.
[0043] FIG. 20 is a plan view of an endovascular prosthesis of the
present invention showing primary material on the membrane and
grafts.
[0044] FIG. 21 shows the endovascular prosthesis of FIG. 20 showing
the polymeric material sealably securing the tubular graft to a
membrane.
DETAILED DESCRIPTION OF THE INVENTION
[0045] The present invention relates to an endovascular prosthesis
for intraluminal delivery, as shown in FIGS. 1-21. The prosthesis
is particularly suited for use as a vascular prosthesis. The
prosthesis of the present invention overcomes the aforementioned
problems of the prior art including leaking and wearing between a
tubular prosthesis and a stent. Additionally, the prosthesis of the
present invention provides flexibility to adapt to the morphology
of the vascular environment. The prosthesis of the present
invention includes minimal components to provide for a simple
assembly in situ.
[0046] One embodiment of the present invention is a prosthesis 1 as
shown in FIG. 1-3. The prosthesis 1 is a generally tubular
structure which includes a stent 2 and a membrane 3.
[0047] The stent 2 of the present invention is similar to those
known in the art. The stent 2 can be open-celled or porous which is
in direct contact with the aortic wall. This permits ingrowth of
cells for the stabilization of implanted endoprosthesis, and device
fixation. The stent may further be coated with various materials as
known in the art to encourage cell growth therethrough. In
addition, the stent 2 may incorporate a covering, or a graft
composite (not shown) to prevent blood flow therethrough. The stent
2 may be covered or coated on the stent's exterior, interior or
both depending on the application.
[0048] As is known in the art, a stent has two diameters, the
compressed diameter and the expanded diameter wherein the
compressed diameter is substantially smaller than the expanded
diameter. The compressed diameter of a stent varies depending on
the materials of construction and structure of a stent. In general,
the compressed diameter must be small enough to allow for
implantation through the vasculature via a minimally invasive
deployment system (not shown). The expanded diameter needs to be
substantially the same diameter-as the vasculature in which it is
to replace or repair. The expanded diameter needs to be large
enough to allow a stent to sufficiently secure to the aortic wall
without acting as a driving force to expand or dilate the
vessel.
[0049] Various stent types and stent constructions may be employed
in the invention. Stents may be capable of radially contracting, as
well, and in this sense can best be described as radially
distensible, deformable or conformable. Stents may be balloon
expandable or self-expandable. Balloon expanding stents include
those that are radially expanded by an applied force.
Self-expanding stents include those that have a spring-like action
which causes the stent to radially expand, or stents which expand
due to the pre-set memory properties of the stent material for a
particular configuration at a certain temperature range. Nitinol is
one material which has the ability to perform well while both in
spring-like elastic mode, as well as in a memory mode based on
temperature. Other materials are of course contemplated, such as
stainless steel, tantalum, platinum, gold, titanium and other
bicompatible metals, as well as shape memory polymers or polymeric
based stents, or indeed composites of the aforementioned.
[0050] The configuration of a stent may also be chosen from a host
of geometries. For example, wire stents can be fastened into a
continuous helical pattern, with or without a wave-like or zig-zag
in the wire, to form a radially deformable stent. Individual rings
or circular members can be linked together such as by struts,
sutures, welding, interlacing or locking of the rings to form a
tubular stent structure. Tubular stents useful in the present
invention also include those formed by etching or cutting a pattern
from a tube. Such stents are often referred to as slotted stents.
Furthermore, stents may be formed by etching a pattern into a
material or mold and depositing stent material in the pattern, such
as by chemical vapor deposition or the like.
[0051] As shown in FIGS. 1 and 2, stent 2 has a pair of spaced
apart ends, a distal end 4, and a proximal end 5, and a tubular
wall structure therebetween. The tubular wall structure has an
external surface and an internal surface which defines the inner
lumen 6 of stent 2. The membrane 3 is supported by stent 2 and
extends across the inner lumen 6 of stent 2. The membrane 3 has one
or more graft receiving members 7 for sealably receiving at least
one tubular graft therethrough. The graft receiving member 7 is
defined as a weakened section, a slit, a hole, a penetrable
material, a punchout, a puncture, a valve and the like.
[0052] Generally, membrane 3 is impermeable to blood, but the
membrane material can be permeable to blood and coated to be or
become impermeable in situ. Membrane 3 may be made from a variety
of well known materials, provided they have the requisite strength
characteristics and biocompatibility properties. Membrane 3 is made
from a flexible and compressible material. In addition, membrane 3
may be synthetic or natural. Examples of such materials are
polymers, elastomers, rubbers, waxes, silicone, parylene,
polyurethane, vinyl polycaprolactone, (TEFLON)
polytetrafluoroethylene, polypropylene, polyethylene, DACRON,
allograph, zeno-graph material, latex, as well as composites of the
aforementioned. Examples of commercially available materials are
Corethane (Corvita); Carbothane (Thermedics); Silastic, Pellethane,
and Parylene (Specialty Coating Systems). The material can be
extruded, knitted, woven, or electrostatically spun material.
[0053] Additionally, membrane 3 can be coated or impregnated with
bio-erodible, biodegradable or degradable material such as
polymers, albumin, collagen, heparin or similar coating material.
The membrane could have a coating of a biologically inert material,
such as PTFE, or porous polyurethane. The coating can be added to
the membrane by methods known in the art such as dipping, spraying
or vapor disposition on the material.
[0054] The thickness of membrane 3 can vary depending on the
application and the material of construction of membrane 3.
Generally, the thickness of the membrane is less than the distance
between distal end 4 and proximal end 5 of the stent 2. Therefore,
some part of stent 2 extends above and/or below membrane 3. For
example, in a vascular application membrane 3 can range from 0.001
mm-0.6 mm, preferably 0.1 mm-0.4 mm.
[0055] Membrane 3 may be a planar surface or a variety of shapes
depending on the application. Membrane 3 can be shaped to assist in
bonding membrane 3 to stent 2 and/or to provide sealable securement
of a tubular graft to membrane 3. For example, FIG. 1 shows
membrane 3 having a peak formation 3a and 3b, having the graft
receiving member located at the top of the peak formation 3a and
3b. The peak formation 3a and 3b assist in sealing between a
tubular graft and membrane 3 by providing more surface area contact
between the two surfaces, shown in FIG. 5 as peak formation 13a and
13b and tubular graft 18. A cup-shape, or sock-shape membrane
assists in attaching the membrane within the stent lumen by
providing more surface area for the membrane to bond to a
stent.
[0056] FIGS. 1 and 3 show membrane 3 attached to and supported by
inner lumen 6 of the stent 2. Membrane 3 can be attached to stent 2
by adhesive bonding, such as silicone or polyurethane; mechanical
attachment, such as sutures or staples; thermal bonding, laminate;
or chemical bonding. In addition, the inner surface of stent 2 may
be coated with an elastomer or polymer and a solvent may be used to
bond the coated inner surface to the membrane. Membrane 3 can be
positioned across inner lumen 6 of stent 2 at any location along
stent 2 such as across the distal end 4, the proximal end 5 or
there between of stent 2.
[0057] As shown in FIG. 1-3, the membrane 3 extends transversely
across the inner lumen of stent 2 with a peak formation 3a and 3b
located centrally in the membrane 3. A graft receiving member 7 is
located at the top of each peak formation 3a and 3b. FIG. 2 shows
the peak formation 3a and 3b directed in the cephalic direction,
but it can be appreciated that the peak formation 3a and 3b can be
inverted such that the top of the peak is directed toward the
caudal direction, depending on the desired application. In addition
to assisting in sealing a tubular graft to the membrane 3, the peak
formation 3a and 3b acts as a check valve allowing fluid to flow in
one direction across membrane 3, and closes upon no flow of fluid
in that direction. Additionally, the peak formation 3a and 3b
prevents back flow of fluid in the opposite direction through
membrane 3.
[0058] The prosthesis of the present invention as described above
may be used in combination with one or more grafts. As shown in
FIGS. 4 and 5, prosthesis 10 is similar to prosthesis 1 of FIG. 1,
further including graft 18 extending sealably through graft
receiving member 17. The membrane 13 material of the peak formation
13a and 13b conforms around graft 18 and becomes coextensive with a
portion of graft 18 securing graft 18 in a sealable manner. The
flow of blood through graft 18 applies outward radial pressure to
the graft 18 against membrane 13, more specifically peak formation
13a and 13b. Membrane 13 provides an opposing force against graft
18 provided by the membrane's 13 securement to stent 12 restricting
its movement and, additionally, the restricted access of the graft
18 through the graft receiving member 17 of membrane 13. These
opposing forces create a seal between graft 18 and membrane 13. It
can be appreciated that one or more peaks may be formed in membrane
13 material depending on the application.
[0059] Any known graft material, or tubular prosthesis, and
structure may be used to form the graft of the present invention.
The graft preferably has generally a tubular configuration. The
graft may be made from a variety of well known materials, provided
they have the requisite strength characteristics and
biocompatibility properties. Examples of such materials are
polyester, polypropylene, polyethylene, polytetrafluoroethylene,
expanded polytetrafluoroethylene and polyurethane, DACRON, TEFLON
(polytetrafluoroethylene), and PTFE coated DACRON as well as
composites of the aforementioned. The material can be extruded,
woven or knitted, warp or weft knitted. The graft can also be
coated or impregnated with a bio-erodible, or degradable material,
such as albumin, collagen, heparin or similar coating material.
Additionally, the graft could have a coating of a biologically
inert material, such as porous polyurethane.
[0060] In general, the diameter of graft 18 varies depending on the
application but generally at least a portion of graft 18 (or
grafts, if multiple grafts used) should be substantially the same
diameter as the graft receiving member 17. Generally, the diameter
of graft 18 should be large enough to allow for unobstructed blood
flow and prevent retrograde pressure build-up in the blood flow
while maintaining sufficient traction against membrane 13 for
long-term fixation. While cylindrical tubular configurations are
shown, other tubular configurations may be employed.
[0061] Another embodiment of the present invention is a bifurcated
prosthesis 20 as shown in FIG. 6. FIG. 6 shows a first prosthetic
component 21 similar to the prosthesis 1 of FIG. 1 including an
expandable stent 22 and a membrane 23 extending transversely across
the inner lumen of and attached to the stent 22. Membrane 23 has
one or more graft receiving openings 27 or members. The bifurcated
prosthesis 20 further includes a second component 26 including a
branched graft 28. In one embodiment branched graft 28 has an
inverted "Y" shape having two leg portions, 28a and 28b, converging
into one trunk portion 28c. The trunk portion 28c extends into
graft receiving member 27 of the membrane 17 creating a
substantially fluid tight seal between the outer surface of graft
28 and membrane 23. The two leg portions, 28a and 28b, extend into
each iliac artery 8 (8a and 8b). The leg portions (28a and 28b)
remain in place by the pressure from the blood flowing therethrough
and forcing the leg portions (28a and 28b) into each iliac artery 8
(8a and 8b). Additional anchoring stents 24 and 25 can be used in
combination with the leg portions (28a and 28b), as shown in FIG.
6, to provide additional securement of graft 17 to the iliac artery
wall.
[0062] Another bifurcated embodiment of the present invention is
shown in FIG. 7 which is similar to the above described bifurcated
prosthesis 20 of FIG. 6 including a stent 32, a membrane 33
extending transversely across the inner lumen of stent 32, graft
receiving members 37 and grafts 38. However, the bifurcated
prosthesis 30 of FIG. 7 includes two separate graft 38 (38a and
38b) instead of the branched graft 28 of FIG. 6. As shown in FIG.
7, grafts 38 extends into separate graft receiving members 37 (37a
and 37b) and form a substantially fluid tight seal between grafts
38 and membrane 33. Additional anchoring stents 34 and 35 can be
added for securing grafts 38 to the iliac vessel wall (8a and
8b).
[0063] Another embodiment of the present invention is shown in
FIGS. 9 and 10 which is similar to the prosthesis 1 of FIG. 1
including an expandable stent 42 and a membrane 43 attached to
stent 42 and extending transversely across the lumen of stent 42.
Membrane 43 of FIG. 9 includes electrostatically spun material.
FIG. 9 shows electrostatically spun material formed into a planar
disk shape instead of the peak formation of FIG. 1. The
electrostatically spun material has a graft receiving opening 47,
similar to graft receiving member 7 of FIG. 1, for sealably
receiving at least one tubular graft therethrough. It can be
appreciated that a variety membrane 43 of shapes and locations on
stent 42 can be used depending on the application, as
above-discussed. Generally, electrostatically spun material is
similar to material known in the art for vascular grafts. The spun
structure of the membrane provides a porous scaffolding structure
for blood to clot within and provide a sealable material. The basic
process of electrospinning in well known in the art. The process
involves the introduction of electrostatic charge to a stream of
polymer melt or solution in the presence of a strong electric
field. The predominant form of operation entails charge induction
in the fluid through contact with a high voltage electrode in a
simple metal or glass capillary spinnerette. A charge jet is
produced which accelerates and thins in the electric field,
ultimately collecting on a grounded device, typically a plate or
belt. Under certain conditions of operation, the fluid jet becomes
unstable before it reaches the collector. The onset of instability,
with low molecular weight fluids, typically results in a spray of
small, charged droplets, in a process known as "electrospinning"
permitting. Viscoelastic forces stabilize the jet, with polymeric
fluids, permitting the formation of small diameter, charged
filaments that appear as an "envelope" or a cone dispersed fluid,
and that solidify and deposit on the collector in the form of a
nonwoven fabric. Under these conditions, it is common to observe
mean fiber diameters on the order of 0.1 .mu.m, three orders of
magnitude smaller than the diameter of the jet entering the
unstable region (10-100 .mu.m). The electrostatic spinning process
is described in U.S. Pat. No. 4,044,404 and U.S. Pat. No.
4,323,525, and is hereby incorporated herein by reference.
Additionally, the material is permeable. The pore size of the
material will usually be between 0.001.mu. and 500.mu.. In order
for the material to be sufficiently porous to allow penetration of
cells into the surface layers, the average surface pore dimension
is preferred to be of the order of 5 to 25.mu., more preferably
between 7 and 15.mu., although pore size in the bulk of the
material may average about 1.mu.. In addition, the membrane may be
coated with a material to promote clotting, or provide a
non-permeable material to prevent fluid flow, such as collagen, or
an elastomer, such as Corethane. Additionally, prosthesis 40 can
include multiple layers of materials forming the membrane such as
an electrospun layer over a silicon layer.
[0064] Prosthesis 40 can be used in combination with various grafts
to provide multi-component systems, bifurcated systems, stent-graft
prosthesis and the like, as shown in FIG. 10. Prosthesis 40 used in
combination with at least one tubular prosthesis 48 extending
through the graft receiving opening 47 and sealably supporting the
tubular prosthesis 48. Generally, the tubular prosthesis 48
includes a graft which is positioned through graft receiving
opening 47 in a compressed state. The graft 48 may vary in size and
shape depending on the desired application. For example, a portion
of the graft 48 extending on either side of the graft receiving
opening 47 may have a larger diameter opening than the portion
extending through the graft receiving opening 47 to provide for
additional securement of the graft 48 to the membrane 43. Once in
place, the graft 48 is allowed to expand in the graft receiving
opening 47. The pressure from the blood through the graft 48
secures the graft 48 to the electrostatically spun membrane, as
similar described above in regards to prosthesis 1 of FIG. 1.
[0065] The above described prosthesis as shown in FIGS. 1-10 can be
loaded into a delivery system for deployment within, a body lumen.
The delivery system used is similar to those known in the art.
Typically, the delivery system has an introductory device or sheath
in which the prosthesis is compressed therein. Once the desired
vascular site is reached, the sheath is removed, leaving the stent
and attached membrane located endoluminally. Additional components
may be used in combination with the above deployed prosthesis such
as a tubular graft. A tubular graft is deployed after the initial
prosthesis is deployed using the same delivery device with an
additional sheath or a separate device.
[0066] Generally, in regards to prosthesis 1 of FIG. 1, the
delivery system includes an elongated outer sheath which supports
the prosthesis 1 in a compressed condition. The outer sheath is an
elongated generally tubular structure which longitudinally
surrounds the prosthesis 1. The outer sheath has a diameter which
is sufficiently small so as to be readily inserted within a body
lumen.
[0067] The deployment system may further include guidewires,
multiple sheaths, dilation devices, i.e. balloons, nose caps and
pushers, as known in the art.
[0068] When the delivery system is positioned at the desired site
in the body lumen the outer sheath is retracted with respect to the
prosthesis 1. The retraction of the outer sheath progressively
releases stent 2 along its longitudinal (axial) extent and allows
the stent 2 to radially expand. As stent 2 further expands membrane
3, which is positioned within the stent 2, is deployed. Membrane 3
radially deploys by the radially expanding force of attached stent
2.
[0069] Prosthesis 40 as shown in FIG. 9 may be deployed using the
same method as described above, and known in the art.
[0070] Deploying the above-described prosthesis in combination with
a graft is a multi-step deployment process. The initial step is
deploying the first prosthesis including the stent and attached
membrane as above-described.
[0071] Generally, after the first prosthesis is positioned and
deployed then the tubular prosthesis is positioned and deployed
using various systems as known in the art. For example, additional
sheaths may be added to the first delivery device, above-described,
to deploy the tubular graft after deploying the first prosthesis.
An example of a multi-stage delivery device which is useful for
delivering the first prosthesis and tubular prosthesis is described
in U.S. Pat. No. 6,123,723 to Konya, and is hereby incorporated
herein by reference. Alternatively, second separate delivery system
can be used to deploy the tubular prosthesis. After the initial
prosthesis is deployed as described above, an additional deployment
device is used to position the tubular prosthesis within the graft
receiving member of the membrane. Once the additional deployment
device is in position the sheath is retracted allowing the tubular
prosthesis to be placed within the graft receiving member. The
tubular prosthesis securably seals to the membrane by the blood
flowing through the tubular prosthesis and forcing the tubular
prosthesis to radially expand against the membrane. Additionally,
stents may be deployed to secure the tubular prosthesis to the
arteries.
[0072] Similarly, a bifurcated system uses the same multi-step
delivery process, as above-described. Additional sheaths and/or
deployment devices are used to deploy the tubular prosthesis as
above-described. For example, FIG. 8 shows a bifurcated system
where the tubular prosthesis are being implanted after the initial
prosthesis 30a including stent 32a and attached membrane 33a is
deployed. The tubular prosthesis 38a and 38b are navigated to the
abdomen. This would be accomplished by mounting the tubular
prosthesis 38a and 38b onto catheters 36 and 39 and thereafter
percutaneously inserting the catheters into a femoral artery and
navigating the tubular prosthesis to the target site. Guidewires
can be used to help delivery of the catheter to the target site.
Navigating catheters within the human arterial system is well known
in the art. An example of a balloon catheter is given in U.S. Pat.
No. 5,304,197 issued to Pinchuck et al. on Apr. 19, 1994, which is
hereby incorporated herein by reference. The target site is, as
previously mentioned, through the graft receiving member 37a and
37b of the membrane 33a. The sheath of the catheter is removed,
placing the tubular prosthesis 38a and 38b within the graft
receiving members 37a and 37b. Removal of the catheter permits the
blood to flow through the tubular prosthesis 38a and 38b further
securing such prosthesis 38a and 38b within the graft receiving
members 37a and 37b, and ultimately sealably securing the tubular
prosthesis 38a and 38b to the stent 32a. Distal anchoring stents
(not shown) can be used to secure the tubular prosthesis 38a and
38b to the walls of the iliac arteries. Distal anchoring stents can
be mounted on and deployed using the same catheter as used
delivering the tubular prosthesis 38a and 38b. Alternatively, the
anchoring stents can be deployed by using a separate deployment
device after placement of the tubular prosthesis 38a and 38b has
been completed.
[0073] FIG. 7 shows how the entire system looks after the
bifurcated prosthesis 30 including stent 32 and attached membrane
33, grafts 38 and anchoring stents 34 and 35 have been
deployed.
[0074] The delivery of prosthesis 20 including a branched graft 28
of FIG. 6 is similar to the delivery of prosthesis 30 of FIG.
8.
[0075] Initially the prosthesis 20 including stent 22 and attached
membrane 23 are delivered to the desired sight as above-described.
A second delivery system is used to implant the branched graft 28
in a compressed state within the graft receiving member 27 of the
membrane 23. Once in place the sheath is removed allowing graft 28
to expand within the graft receiving member 27, one leg 28a of
graft 28 is in place and may be anchored with an anchoring stent
24. A third delivery device is used to properly position the other
leg 28b of the branched graft 28 and additionally add an anchoring
stent 25 to secure the graft within the iliac artery 8b. FIG. 6
shows how the entire system looks after the prosthesis 20 including
the branched graft 28 is deployed.
[0076] It may be desirable to have additional securement of the
prosthesis to the aortic wall. Multiple prosthesis, as described
above, can be used in combination to offer securement of the
prosthesis cephalically to the renal arteries. For example, FIG. 11
shows a multi-component endovascular prosthesis 50 of the present
invention which includes a first expandable prosthesis 51, and
second expandable prosthesis 61. The prosthesis, 51 and 61, are
similar to the prosthesis 1 in FIG. 1 including a stent, and a
membrane extending traversely across the inner lumen and attached
to the stent, and having one or more graft receiving members. The
first expandable prosthesis 51 and second expandable prosthesis 61
include an expandable stent (52, 62), and a membrane (53, 63)
having graft receiving openings (57, 67), respectively. FIG. 11
shows the first expandable prosthesis 51 further including fluid
flow opening 54 to provide an outlet for fluid to flow through the
membrane 53. The fluid flow opening 54 includes a slit, a hole, a
fluid penetrable material and the like. FIG. 11 shows a bifurcated
system including tubular grafts 58 (which includes 58a and 58b)
which extends sealably through each prosthesis, (51, 61) at the
graft receiving opening (57, 67) for directing fluid through the
tubular grafts 58. In addition, FIG. 11 shows grafts 58 including a
porous portion 59 (which includes 59a and 59b) disposed on grafts
58 between the first expandable prosthesis 51 and the second
expandable prosthesis 61 to allow for fluid exchange through the
porous portion 59 of grafts 58. The porous portion 59 includes a
stent, slits, fluid permeable material and the like.
[0077] Deployment of prosthesis 50 is similar to those prosthesis
as above-described. For an abdominal aortic aneurysm application,
the first expandable prosthesis 51 is positioned and deployed
cephalic to the renal arteries 9 (includes 9a and 9b) via a
delivery device in the same manner as described above. The same
delivery device using additional sheaths or a second delivery
device is used to implant second expandable prosthesis 61 between
the renal arteries 9 and the abdominal aneurysm. An additional
delivery device is used to deliver grafts 58 through the graft
receiving opening (57, 67). Graft 58a is extended through graft
receiving opening (57, 67) of each prosthesis (51, 61),
respectively. Second graft 58b is extended through graft receiving
opening (57, 67). Grafts 58a and 58b are extended sealable through
the graft receiving openings (57,67) for directing fluid
therethrough. The same deployment procedure as above-discussed is
used to delivery prosthesis 50, as known in the art.
[0078] A further embodiment of the present invention is an
endovascular prosthesis 70 of FIG. 12, which is similar to
prosthesis 1, of FIG. 1 including a stent and a membrane. FIG. 12
shows the "M" shaped stent 72 having an inner lumen 76, a distal
end 74 and a proximal end 75. The distal end 74 has an opening and
the proximal end 75 has two openings opposed the distal opening. A
puncturable membrane 73 extends across each of the proximal end 75
openings for puncturably receiving a graft. The stent 72 of FIG. 12
is similar to the stents as above-described but is preferably a
weave or braid of stent filaments. As shown in FIG. 13, a typical
braided stent includes a first set of filaments 71L wound in a
first helical direction (to the left as shown in FIG. 13) and a
second set of filaments 71R wound in a second, opposite helical
direction (to the right as shown in FIG. 13), forming a plurality
of overlaps 79. Filaments 71L and 71R may be wire, such as nitinol
or stainless steel, or may comprise polymer or any type of
filaments known in the art. The prosthesis 70 may be a hybrid
material having two materials woven or bonded together such as a
PTFE and Dacron, where Dacron is bonded on the exterior of the
PTFE.
[0079] As used herein, a "braided" stent refers to a stent formed
of at least two continuous filaments which are interwoven in a
pattern, thus forming overlaps 79 as shown in FIG. 13. At each
overlap, one filament is positioned radially outward relative to
the other filament. Following each filament along its helical path
through a series of consecutive overlaps, that filament may, for
example be in the radial inward position in one overlap and in the
radial outward position in a next overlap, or may in the inward
position for two overlaps and in the outward position for the next
two, and so on. Exemplary braided stents are disclosed in U.S. Pat.
No. 4,655,771 to Hans I. Wallsten, and is incorporated herein by
referred. The endovascular prosthesis 70 may include a stent-graft
composite where the stent is an open structure with a non-permeable
graft material attached thereto. A stent-graft composite can
further have a stent with one opening at the distal end and a
crimped opening at the proximal end supporting a graft which forms
the two openings at the proximal end 75.
[0080] The endovascular prosthesis of FIG. 12 further includes a
puncturable membrane 73 which is similar to membrane 3 of FIG. 1 as
described-above having weakened section, opening, slit, or hole for
receiving a graft therethrough. Membrane 73 is similarly attached
to stent 72 as described above by mechanical, thermal, chemical,
and adhesively attached. Membrane 73 and/or graft receiving opening
77 forms a fluid seal between the tubular prosthesis 78 and the
stent 72 at the proximal end 75.
[0081] The endovascular prosthesis 70 of FIG. 12 is shown in
combination with tubular prosthesis 78. Any number of tubular
grafts may be used depending on the application. FIG. 12 shows the
tubular prosthesis 78 extending through the distal end 74 opening
of the prosthesis 70 and puncturably through membrane 73 thereby
forming a fluid seal between the tubular prosthesis 78 and the
stent 72 at the proximal end 75. Blood flow is directed through the
tubular prosthesis 78. The tubular prosthesis 78 are positioned in
each iliac artery so that the blood exits the tubular prosthesis 78
into each iliac artery (8a, 8b).
[0082] The deployment of prosthesis 70 is similar to the manner of
deployment described for prosthesis 1 of FIG. 1. Generally, the
delivery system is positioned in the body lumen, and the outer
sheath is retracted with respect to the prosthesis 70. The
retraction of the outer sheath progressively releases the stent 72
along its longitudinal (axial) extent and allows the stent 72 to
radially expand. The membrane 73, which is positioned across the
stent lumen 76, is radially deployed by the radially expanding
force of the attached stent 72.
[0083] Additionally, secondary delivery devices are used to deploy
tubular prosthesis 78 through the graft receiving membrane 77,
similar to those above-described. The implanted bifurcated system
is shown in FIG. 12.
[0084] A further embodiment of the present invention similar to
FIG. 12 is shown in FIG. 14 which provides for additional
securement of the prosthesis cephalically to the renal arteries 9
(includes 9a and 9b). FIG. 14 shows an endovascular prosthesis 80
where a portion of the prosthesis 80 caudal to the renal arteries
9, similar to the embodiment 70 of FIG. 12, has an "M" shaped
configuration with an opening at one end and two openings 84 at the
opposed end. The endovascular prosthesis 80 of FIG. 14 is a
graft-stent composite including a stent 82, grafts 86 and membranes
83. The stent 82 extends the full length of the prosthesis 80
having a distal end 87, a proximal end 88 and an opening extending
therethrough. As shown in FIG. 14, a portion of the endovascular
prosthesis 80 cephalic to the renal arteries 9 includes a first
graft 81 which is attached to the distal end 87 of the stent 82
having an inner lumen therethrough. A portion of the prosthesis 80
caudal to the renal arteries 9 includes a second graft 86 which is
attached to the proximal end 88 of the stent 82 and forms the "M"
shape, similar to the prosthesis 80 of FIG. 14. The second graft 86
forms two smaller lumens 84 within the stent 82 opening. Membrane
83 extends transversely across each of the two lumens 84 of the
second graft 86. Membrane 83 is similar to the construction
materials as described for that of prosthesis 1 of FIG. 1. Membrane
83 can be attached to graft 86, in the manner as above-described,
by adhesive bonding, such as silicone or polyurethane; mechanical
attachment, such as sutures or staples; thermal bonding, laminate;
or chemical bonding. The two grafts 81 and 86 are spaced apart to
provide for blood exchange through the stent 82 and renal arteries
9. The section of the stent 82 between the first graft 81 and
second graft 86 may be an open celled structure or a covered stent
which is blood-permeable. FIG. 14 shows the endovascular prosthesis
80 having a wider cross-sectional area at distal end 87 and
proximal end 88 where the stent 82 secures the prosthesis 80 to the
artery wall, and a narrow cross-sectional area there between. One
can appreciate that the endovascular prosthesis 80 may be one
cross-sectional area throughout the length of the prosthesis 80 or
varying cross-sectional areas as long as the two ends provide for
securement to the artery wall and allow for undisturbed blood-flow
therethrough.
[0085] Prosthesis 80 can be used in combination with a tubular
prosthesis 89 as shown in FIG. 14. The tubular prosthesis 89
extends through each of the respective membranes 83 and provides a
sealable attachment between the graft 86 and the tubular prosthesis
89. The blood is diverted into each tubular prosthesis 89. The
tubular prosthesis 89 is those known in the art and above-described
in reference to the prosthesis 10 in FIG. 4.
[0086] To deploy the prosthesis 80, the prosthesis 80 is typically
compressed into a radially compressed state into a delivery device,
as known in the art and above-described. The prosthesis 80 is then
introduced to the lumen into which it is to be deployed, navigated
through the lumen to a deployment location, typically a diseased
artery such as the aorta. The prosthesis 80 is expanded to a
radially expanded state in the deployment location as is known in
the art. FIG. 14 shows the prosthesis 80 deployed across the renal
arties 9a and 9b where the open-cell structure or porous portion of
the prosthesis 80 is between the renal arteries 9a and 9b. The
deployment of the tubular prosthesis 89 (89a and 89b) of the
present invention is thus deployed by a method similar to that
described above using a separate delivery device or the same
delivery device with additional sheaths or stages, as known in the
art. The tubular prosthesis 89 are puncturably delivered through
the membrane 83. The tubular prosthesis are sealably secured to the
graft 86 by the outward force from the blood flowing there through
and the restricted size of the lumens 84.
[0087] Another embodiment of the present invention which is similar
to prosthesis 1 of FIG. 1 but instead of using a membrane to
sealable secure a tubular prosthesis to the stent, a foam 93 is
used to securely attaching the tubular prosthesis 98 to the stent
92 as shown in FIG. 15. The endoprosthesis 90 of FIG. 15 includes a
stent 92, and a tubular prosthesis 98 having an expanded foam 93
attached thereto. The stent 92 is similar to those described above
being an expandable stent 92 having a distal end, a proximal end
and an inner lumen. As shown in FIG. 16, stent 92 has an inner
surface 94 and an outer surface. The tubular prosthesis 98 is
similar to those described above having an interior surface and
exterior surface 99. The expanded foam 93 is attached to the
exterior surface 99 of the tubular prosthesis 98. The tubular
prosthesis 98 is placed within the lumen 91 of the stent 92 and the
expanded foam 93 sealably secures the tubular prosthesis 98 to the
stent 92.
[0088] The expandable foam 93 must be biocompatible and requisite
strength characteristics. The foam is similar to those known in the
art such as gelatin sponge, collagen sponge, cellulose sponge,
hyaluronic acid and foams used for nasal surgery. The expandable
foam 93 may be porous or non-porous. The expandable foam 93 is
provided in a compressed state prior to placement within the stent
92. Once in place, the expandable foam 93 is allowed to expand into
the matrix of stent 92 to securably attach the tubular prosthesis
98 in the stent lumen 91. Some expandable foams are non-permeable
upon implantation, while others provide a scaffold structure for
clot formation. Some scaffold structure foams may dissolve over
time leaving a sealable clot formation. Suitable available
commercial foams include Spongostern, Surgifoam, (Ferrosan,
distributed by Johnson & Johnson); Gelfoam (Pharmacia &
UpJohn Company); Avitene Ultrofoam (Bard/Davol); MeroGel Nasal
Dressing, Sinus Stent and Otologic Packing, HYAFF (Medtronic Xomed,
Jacksonville, Fla.).
[0089] The expandable foam 93 is attached to the outer surface 99
of the tubular prosthesis 98 by mechanical, adhesive, thermal, or
chemical attachment. As shown in FIG. 16, the foam 93 covered graft
98 is placed into the lumen 91 of the stent 92 and the expandable
foam 93 is allowed to expand by either a reaction in the vascular
environment, such as hydrolysis, or by removing an outside force,
such as sheath. The expandable foam 93 expands against and into the
structure of the stent 92 securing the tubular prosthesis 98 in
place in a sealable manner. As shown in FIG. 16 one or more tubular
prosthesis 98 can be used depending on the application.
[0090] Additionally, as shown in FIG. 17, the expandable foam 93
covered tubular prosthesis 98 of FIG. 16 can be used in combination
with the prosthesis 1 of FIG. 1. Prosthesis 90a includes a stent
92a and a membrane 97 having a graft receiving member 97a, similar
to prosthesis 1 of FIG. 1. The expandable foam 93a covered tubular
prosthesis 98a is extended through the graft receiving member 97a.
The expandable foam 93a expands within the graft receiving member
97a to provide a sealable securement of the tubular prosthesis 98a
to the membrane 97, as shown in FIG. 17.
[0091] Further the embodiment of the present invention is a kit of
parts for assembly into an endovascular prosthetic system. The kit
includes an expandable stent 92 and a tubular prosthesis 98. The
expandable stent 92 has a distal end, a proximal end and an inner
lumen 91 for insertion into a body endovascularly. The tubular
prosthesis 98 is adapted to be inserted within the inner lumen 91
of the stent 92. The tubular prosthesis 98 has an interior surface
for body fluid flow and an exterior surface. Additionally, an
expandable foam 93 is attached to the exterior surface of the
tubular prosthesis 98. The expandable foam 93 is adapted to expand
within the stent 92 to sealably secure the tubular prosthesis 98 to
the stent 92.
[0092] Deploying prosthesis 90 is similar to the method of
deploying prosthesis 30 of FIG. 7. The prosthesis 90 is a
multi-step process as above-discussed. The stent 92 is typically
compressed into a radially compressed state into a delivery device,
as known in the art. The stent 92 is then introduced into the lumen
in which it is to be deployed, navigated through the lumen to a
deployment location, and then expanded to a radially expanded state
in the deployment location, as is known in the art. The expandable
foam 93 covered tubular prosthesis 98 are also compressed into a
radially compressed state into a delivery device. Once the tubular
prosthesis 98 are positioned within the stent lumen 91 the tubular
prosthesis 98 are deployed by removing a restraining element, such
as a sheath, of the delivery device. The expandable foam 93 is
allowed to expand filling the space within the stent lumen 91, into
the structure of the stent 92, and sealably securing the tubular
prosthesis 98 within the stent 92. As above-discussed separate
delivery devices may be used to deploy each component of the
prosthesis 90 or a multi-step delivery device may be used.
[0093] In addition, prosthesis 90a of FIG. 17 is deployed using the
same delivery system as above-described for prosthesis 90 of FIG.
16, except the stent 92 of FIG. 16 is substituted with the first
prosthesis 91a. Initially, first prosthesis 91a is compressed in a
delivery device, delivered to the target site within the lumen and
allowed to deploy at the site. The expandable foam 93a covered
tubular prosthesis 98a are delivered via the delivery device in a
compressed state into the graft receiving member 97a. After placing
the delivery device within the graft receiving members 97a at the
desired location, the delivery device is removed to allow the
expandable foam 93a to expand within the graft receiving members
97a. The expandable foam 93a in combination with the graft
receiving members 97a sealably secure the tubular prosthesis 98a to
the first prosthesis 91a.
[0094] A further embodiment of the present invention is an
endovascular prosthetic assembly 100 as shown in FIGS. 18 and 19
which is similar to the prosthesis 90 of FIG. 15 but instead of
using an expandable foam on the grafts to secure the grafts to the
stent, a polymeric material 130 is used. FIG. 19 shows the
endovascular prosthetic assembly 100 including a stent 120 and a
tubular prosthesis 180 similar to those described above.
Endovascular prosthetic assembly 100 further includes a polymeric
material 130 sealably supporting the tubular prosthesis 180 to the
stent 120. The polymeric material 130 is a substantially homogenous
reaction product of monomer materials which is formed in situ. As
shown in FIG. 18, the exterior surface of the tubular prosthesis
180 and inner surface of the lumen of the stent 120 are pre-coated
with a primary reactive material 110. The tubular prosthesis 180 is
positioned within the inner lumen of the stent 120. A secondary
material (not shown) reactive with the primary material 110 is
introduced in the vicinity of tubular prosthesis 180 and the inner
lumen of the stent 120. The primary material 110 and secondary
material react forming a polymeric material 130 which sealably
supports the tubular prosthesis 180 to the stent 120.
[0095] In general, the polymeric material 130 is biocompatible,
slightly thrombotic, and non-toxic. The polymeric material 130 can
be a foam or hydrogel. A hydrogel which is useful is one formed
from the mixture of a polymer and monomer and an reaction promoter
such as a chemical activator or light activator (focal
therapeutic). Examples of suitable materials which react to form a
hydrogel include polyethylene glycol and iron, or polyethylene
glycol and peroxide in addition to light activation or a chemical
activator. For additional suitable hydrogel and methods of
preparation, refer to U.S. Pat. No. 6,379,373 to Sawhney, which is
hereby incorporated herein by reference.
[0096] In addition, one or more tubular prosthesis 180 can be used
depending on the application. The prosthesis 100 can be offered in
a kit form. The kit of parts for assembly into an endovascular
prosthetic system 100 includes a stent 120, a primary reactive
material 110, a tubular prosthesis 180, and a secondary reactive
material. The stent 120 has an inner surface, an outer surface and
an inner lumen. The primary reactive material 110 is disposed on
said inner surface of the stent 120. The tubular prosthesis 180 is
adapted to extend within the inner lumen of the stent 120. The
tubular prosthesis 180 has an interior surface and an exterior
surface, and the primary material 110 is disposed on said exterior
surface of the tubular prosthesis 180. The secondary material is
reactive with the primary material 110 and adapted to be applied to
the primary material 110 upon insertion of the tubular prosthesis
180 within the inner lumen of the stent 180. The secondary material
is reactive with the primary material 110 to form a seal between
the tubular prosthesis 180 and the stent 120.
[0097] Deploying prosthesis 100 is similar to the deployment
process of prosthesis 90 of FIG. 15. The prosthesis 100 is also a
multiple step process as above-discussed. The stent 120 is
compressed into a radially compressed state into a delivery device,
as known in the art. The stent 120 is then introduced to the lumen
into which it is to be deployed, navigated through the lumen to a
deployment location, and then expanded to a radially expanded state
in the deployment location, as is known in the art. Secondarily,
the tubular prosthesis 180 are compressed in a radially compressed
state within a delivery device. The tubular prosthesis 180 are
positioned within the lumen of the stent 120. The tubular
prosthesis 180 are partially deployed by removing the sheath or
delivery device around the portion of the tubular prosthesis 180
which is positioned within the lumen of the stent 120. A secondary
material is injected into the vicinity of the tubular prosthesis
180 and stent 120. The secondary material is allowed to react with
the primary material 110 on the exterior surface of the tubular
prosthesis 180 and the interior surface of the stent 120. The
polymeric reaction product 130 from the two materials sealably
secures the tubular prosthesis 180 to the stent 120. As above
discussed separate delivery devices may be used to deploy each
component of the prosthesis 100 or a multi-step delivery device may
be used, as known in the art.
[0098] In addition, combining the technology as shown in FIGS. 18
and 19 with the prosthesis 1 of FIG. 1, provides prosthesis 200 as
shown in FIGS. 20 and 21. In this combination, the membrane 230 and
the tubular prosthesis 280 are pretreated with the primary material
210, as described above. FIG. 20 shows tubular prosthesis 280 is
placed within the stent lumen through the graft receiving member
270 of the membrane 230. A secondary material is introduced which
reacts with the primary material 210 on the tubular prosthesis 280
and the membrane 230. A polymeric material 240 is formed which
sealably secures the tubular prosthesis 280 to the stent 220, as
shown in FIG. 21.
[0099] Prosthesis 200 is deployed in the same manner as discussed
for prosthesis 100 of FIG. 18, except stent 120 is replaced with a
first prosthesis 219 including a stent 220 and a membrane 230,
attached to the stent 220, having graft receiving member 270. The
first prosthesis 219 is deployed at the target site using a
delivery device as above described. The tubular prosthesis 280 is
compressed in a delivery device and then positioned through the
graft receiving members 270. The tubular prosthesis 280 is deployed
within the graft receiving members 270. A secondary reactive
material is introduced in the vicinity of the membrane 230 and the
tubular prosthesis 280. The secondary reactive material is allowed
to react with the primary material 210 on the tubular prosthesis
280 and the membrane 230. The reaction product 240 results in a
polymeric material which sealably secures the tubular prosthesis
280 to the membrane 230. Variations on this method may be used
according to the known art.
[0100] Having described particular arrangements of the present
invention herein, it should be appreciated by those skilled in the
art that modifications may be made thereto without departing from
the contemplated scope thereof. Accordingly, the arrangements
described herein are intended to be illustrative rather than
limiting, the true scope of the invention being set forth in the
claims appended hereto.
* * * * *