U.S. patent application number 10/984167 was filed with the patent office on 2005-07-07 for branch vessel prosthesis with anchoring device and method.
Invention is credited to Hoffa, Michael C., Schaeffer, Darin G..
Application Number | 20050149166 10/984167 |
Document ID | / |
Family ID | 34590274 |
Filed Date | 2005-07-07 |
United States Patent
Application |
20050149166 |
Kind Code |
A1 |
Schaeffer, Darin G. ; et
al. |
July 7, 2005 |
Branch vessel prosthesis with anchoring device and method
Abstract
A stent graft system for intraluminal deployment in an aorta and
a branch vessel includes an aorta stent graft for deployment within
an aorta and defining a lumen for the passage of blood
therethrough, and having a fenestration aligned so as to allow
blood to flow to a contiguous branch vessel. A branch vessel
prosthesis having a flaring portion, a tubular portion and an
anchoring device, are configured so that, upon deployment, the
tubular portion passes through the fenestration and into the branch
vessel, the anchoring device affixes the position of the tubular
portion within the branch vessel, and the flaring portion is
retained within the lumen of the aorta stent graft and is
maintained against an inside wall of the aorta stent graft to
thereby bias the aorta stent graft toward the branch vessel.
Inventors: |
Schaeffer, Darin G.;
(Bloomington, IN) ; Hoffa, Michael C.;
(Brownsburg, IN) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE/CHICAGO/COOK
PO BOX 10395
CHICAGO
IL
60610
US
|
Family ID: |
34590274 |
Appl. No.: |
10/984167 |
Filed: |
November 8, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60518565 |
Nov 8, 2003 |
|
|
|
Current U.S.
Class: |
623/1.13 |
Current CPC
Class: |
A61F 2002/8486 20130101;
A61F 2230/0078 20130101; A61F 2/915 20130101; A61F 2002/075
20130101; A61F 2/958 20130101; A61F 2/07 20130101; A61F 2/954
20130101; A61F 2230/0067 20130101; A61F 2210/0076 20130101; A61F
2/856 20130101; A61F 2/89 20130101; A61F 2230/005 20130101; A61F
2250/0097 20130101; A61F 2002/065 20130101; A61F 2002/91566
20130101; A61F 2002/8483 20130101; A61F 2002/067 20130101; A61F
2250/0098 20130101; A61F 2002/91558 20130101; A61F 2220/0075
20130101; A61F 2250/0018 20130101; A61B 2017/1107 20130101; A61F
2002/821 20130101; A61F 2002/91533 20130101; A61F 2/91 20130101;
A61F 2220/0016 20130101; A61F 2220/0083 20130101; A61F 2230/0054
20130101; A61F 2250/0039 20130101; A61F 2002/9511 20130101; A61F
2/064 20130101; A61B 2017/1139 20130101; A61F 2002/91508 20130101;
A61F 2002/91525 20130101; A61F 2220/005 20130101; A61F 2/88
20130101 |
Class at
Publication: |
623/001.13 |
International
Class: |
A61F 002/06 |
Claims
1. A stent graft system for intraluminal deployment in an aorta and
a branch vessel comprising: an aorta stent graft for deployment
within an the aorta and defining a lumen for the passage of blood
therethrough, and having a fenestration aligned so as to allow
blood to flow to a contiguous branch vessel; and a branch vessel
prosthesis having a flaring portion, a tubular portion and an
anchoring device, wherein the flaring portion, tubular portion and
anchoring device are configured so that, upon deployment, the
tubular portion passes through the fenestration and into the branch
vessel, the anchoring device affixes the position of the tubular
portion within the branch vessel, and the flaring portion is
retained within the lumen of the aorta stent graft and is
maintained against an inside wall of the aorta stent graft to
thereby bias the aorta stent graft toward the branch vessel.
2. The system of claim 1 wherein the anchoring device comprises
barbs extending from the tubular portion.
3. The system of claim 2 wherein the barbs are retained under a cap
until deployment in the branch vessel.
4. The system of claim 3 wherein the cap is released during
deployment by a trigger wire.
5. The system of claim 1 wherein the branch vessel comprises a
graft material affixed to at least the flaring portion of the
branch vessel prosthesis to thereby form a seal with the inner
wall.
6. The system of claim 1 further comprising a graft material
affixed to the branch vessel prosthesis to form a lumen through
which blood passes from the aorta stent graft into the branch
vessel.
7. The system of claim 1 wherein the flaring portion further
comprises a flaring portion anchoring device whereby the flaring
portion is affixed to an inner surface of the aorta stent graft
upon deployment.
8. The system of claim 7 wherein the flaring portion anchoring
device comprises barbs extending into the inner surface of the
aorta stent graft upon deployment.
9. The system of claim 1 wherein the branch vessel prosthesis
comprises metal struts and wherein metal struts in the flaring
portion, when deployed, are curved through an arc of more than 90
degrees with respect to the tubular portion.
10. The system of claim 9 wherein the metal struts in the flaring
portion, when deployed, are curved through an arc of about 180
degrees with respect to the tubular portion.
11. The system of claim 1 wherein the flaring portion forms an
acute angle with the tubular portion when deployed.
12. The system of claim 1 wherein the branch vessel comprises a
stent with metal struts and wherein metal struts in the flaring
portion form an acute angle with the tubular portion when
deployed.
13. The system of claim 1 wherein the branch vessel has a compact
configuration so as to fit within a delivery catheter, and wherein
flaring portion is bent so as to lie over the tubular portion.
14. The system of claim 1 wherein tubular portion comprises a
plurality of Z-stents affixed to a lumen of graft material.
15. The system of claim 14 wherein the flaring portion comprises a
Z-stent affixed to graft material.
16. The system of claim 1 further comprising at least one
positional indicator on the tubular portion at a proximal end.
17. The system of claim 1 further comprising at least one
positional indicator on the tubular portion at a distal end.
18. The system of claim 1 further comprising at least one at least
one positional indicator marker located on the tubular portion so
as to line up with the fenestration.
19. The system of claim 1 wherein the aorta stent graft includes a
seating portion around the fenestration for receiving the flaring
portion and forming a seal therewith.
20. A method of repairing a defect in an aorta and/or a branch
vessel in a patient having an aorta stent graft defining a lumen
and having a fenestration aligned with a branch vessel, comprising,
providing a branch vessel prosthesis having a flaring portion, a
tubular portion and an anchoring device; endoluminally deploying
the branch vessel prosthesis such that the tubular portion passes
through the fenestration and into the branch vessel, and the
flaring portion is retained within the lumen of the aorta stent
graft; and affixing the position of the tubular portion at a
sufficient depth such that the flaring portion is maintained
against an inside wall of the aorta stent graft to thereby bias the
aorta stent graft toward the branch vessel.
Description
RELATED APPLICATIONS
[0001] This application claims priority to provisional application
No. 60/518,565 filed on Nov. 8, 2003, the entire disclosure of
which is incorporated by reference herein.
TECHNICAL FIELD
[0002] This invention relates to medical devices and more
particularly, to endoluminal devices suitable for various medical
applications and the methods for making and using such endoluminal
devices.
BACKGROUND
[0003] The functional vessels of human and animal bodies, such as
blood vessels and ducts, occasionally weaken or even rupture. For
example, an aortic wall can weaken, resulting in an aneurysm. Upon
further exposure to hemodynamic forces, such an aneurysm can
rupture. In Western European and Australian men who are between 60
and 75 years of age, aortic aneurysms greater than 29 mm in
diameter are found in 6.9% of the population, and those greater
than 40 mm are present in 1.8% of the population.
[0004] One intervention for weakened, aneurismal, dissected or
ruptured vessels is the use of an endoluminal device or prosthesis
such as a stent graft to provide some or all of the functionality
of the original, healthy vessel and/or preserve any remaining
vascular integrity by replacing a length of the existing vessel
wall that contains the site of vessel weakness or failure. Stent
grafts for endoluminal deployment are generally formed from a tube
of a biocompatible material in combination with one or more stents
to maintain a lumen therethrough. Stent grafts effectively exclude
the defect by sealing both proximally and distally to the defect,
and shunting blood through its length. A device of this type can,
for example, treat various arterial aneurysms, including those in
the thoracic aorta or abdominal aorta.
[0005] A bifurcated stent graft, one example of an endoluminal
prosthesis, is known for use in treating abdominal aortic
aneurysms, where the stent graft at the proximal end defines a
single lumen for placement within the aorta and at the other end
bifurcates into the iliac arteries. One such stent graft, disclosed
in PCT application WO98/53761, is useful for repair of abdominal
aortic aneurysms. That application discloses a stent graft that
includes a sleeve or tube of biocompatible graft material such as
woven polyester fabric or polytetrafluoroethylene (PTFE) defining a
main lumen and two iliac limbs. The stent graft further includes
several stents secured therealong. The stent graft is designed to
span an aneurysm that extends along the aorta between the iliac and
renal arteries. Unbifurcated stent grafts, in which the distal
portion extends into only one iliac artery in treating an abdominal
aorta, or which are used to treat the thoracic aorta are also
used.
[0006] In the WO98/53761 application, the fabric-covered portion of
the single-lumen proximal end of the stent graft bears against the
wall of the aorta above the aneurysm and distal to the renal
arteries to seal off the aneurysm. Thin wire struts of a juxtarenal
attachment stent traverse the renal artery ostia without occluding
them. Barbs on the attachment stent help anchor the stent graft in
place.
[0007] One stent graft approved by the Food and Drug Administration
(FDA) to treat aortic aneurysms is the ZENITH.RTM. AAA Endovascular
Graft (Cook Incorporated, Bloomington, Ind.). The ZENITH.RTM. AAA
Endovascular Graft is made up of three prosthetic modules: a
bifurcated main body module and two leg modules. The main body is
positioned in the aorta. The legs are positioned in the iliac
arteries and connect to the main body. The stent graft thus extends
from a section of the aorta, typically below the renal arteries and
into both iliac arteries. The graft material is made of a woven
polyester fabric like that used in open surgical repair. Standard
surgical suturing techniques are used to sew the graft material to
a frame of stainless steel stents. These self-expanding stents
provide support for the graft material.
[0008] An endoluminal prosthesis may be comprised of multiple
prosthetic modules. A modular prosthesis allows a surgeon to
accommodate a wide variation in vessel morphology while reducing
the necessary inventory of differently sized prostheses. For
example, aortas vary in length, diameter and angulation between the
renal artery region and the region of the aortic bifurcation.
Prosthetic modules that fit each of these variables can be
assembled to form a prosthesis, obviating the need for a custom
prosthesis or large inventories of prostheses that accommodate all
possible combinations of these variables. A modular system may also
accommodate deployment options by allowing the proper placement of
one module before the implantation of an adjoining module.
[0009] Modular prostheses are typically assembled in situ by
overlapping the tubular ends of the prosthetic modules so that the
end of one module sits partially inside the other module,
preferably forming circumferential apposition through the overlap
region. This attachment process is called "telescoping." The
connections between prosthetic modules are typically maintained by
the friction forces at the overlap region and enhanced by the
radial force exerted by the internal prosthetic module on the
external prosthetic modules where the two overlap. The fit may be
further enhanced by stents attached to the modules at the overlap
region.
[0010] In many cases, however, the damaged or defected portion of
the vasculature may include a branch vessel. For example, in the
case of the abdominal aorta, there are at least three branch
vessels, including the celiac, mesenteric, and renal arteries,
leading to various other body organs. Thus, when the damaged
portion of the vessel includes one or more of these branch vessels,
some accommodation must be made to ensure that the stent graft does
not block or hinder blood flow through the branch vessel.
[0011] Attempts to maintain blood flow to branch vessels have
included providing one or more fenestrations or holes in the side
wall of the stent graft. Other attempts have included providing a
stent graft in which the branch vessel portion of the vessel is
spanned by wires or the like. These devices have been used to treat
diseased vessels, such as abdominal aortic aneurysms within the
aorta that extend to or above the renal, celiac and/or mesenteric
arteries. Generally, this treatment involves aligning the
fenestrations with the branch vessels, which may extend
approximately at right angles on both sides from the aorta.
[0012] In many cases, the vasculature is not symmetric. In
addition, even with symmetrical vasculature, physiological forces
may cause a previously placed branch vessel stent graft to shift
causing the position of the fenestration with respect to the branch
vessel to become offset. In other instances, the diseased
vasculature may extend into the branch vessel and affects the
ostium of the branch vessel. In some circumstances the branch
vessel stent graft deployed within the main vessel may not properly
seal and secure to the branch vessel and lead to leaks (endoleaks)
between the branch vessel stent graft and the main vessel, a
reduced blood flow to the branch vessels, and/or obscure access to
portions of the branch vessel, necessitating further interventional
procedures.
[0013] When treating a vessel with an endoluminal prosthesis, it
may therefore be preferable to preserve the original circulation by
providing a prosthetic branch that extends from the prosthesis to a
side branch vessel so that the blood flow into the branch vessel is
not impeded. For example, the aortic section of the ZENITH.RTM.
abdominal aortic stent graft (Cook Incorporated, Bloomington,
Ind.), described above, can be designed to extend above the renal
arteries, and/or the celiac or mesenteric arteries, and to have
prosthetic side branches that extend into the renal arteries.
Branch vessel prostheses can form a connection to an aortic stent
graft through fenestrations in the stent graft to complete the
prosthesis. Furthermore, some aneurysms extend into the branch
vessels in both the thoracic and abdominal aorta. Deploying
prostheses with prosthetic branches into these vessels may help
prevent expansion and/or rupture of these aneurysms.
[0014] In other situations, it may not be necessary to form a lumen
that extends into the branch vessel, i.e. a stent graft. Instead,
it may only be necessary to maintain patency of the branch vessel
by propping the walls of the branch vessel open, also known as
"stenting." In these situations, the branch vessel prosthesis can
be a mere stent, also known as an "open stent" or "bare stent."
[0015] Thus, there remains a need for a device a branch vessel
stent or stent graft to secure and seal the branch vessel stent
graft to a branch vessel and within a fenestrated device.
SUMMARY
[0016] This application relates to a branch vessel stent for use in
connection with a fenestrated stent graft device for placement in a
vessel of a body.
[0017] In particular, this application relates to a stent graft
system for intraluminal deployment in an aorta and a branch vessel
is provided that includes an aorta stent graft for deployment
within an aorta and defining a lumen for the passage of blood
therethrough, and having a fenestration aligned so as to allow
blood to flow to a contiguous branch vessel. The system further
includes a branch vessel prosthesis having a flaring portion, a
tubular portion and an anchoring device, where the flaring portion,
tubular portion and anchoring device are configured so that, upon
deployment, the tubular portion passes through the fenestration and
into the branch vessel, the anchoring device affixes the position
of the tubular portion within the branch vessel, and the flaring
portion is retained within the lumen of the aorta stent graft and
is maintained against an inside wall of the aorta stent graft to
thereby bias the aorta stent graft toward the branch vessel.
[0018] A method of repairing a defect in an aorta and/or a branch
vessel in a patient having an aorta stent graft defining a lumen
and having a fenestration aligned with a branch vessel is provide.
The method includes providing a branch vessel prosthesis having a
flaring portion, a tubular portion and an anchoring device,
endoluminally deploying the branch vessel prosthesis such that the
tubular portion passes through the fenestration and into the branch
vessel. The flaring portion is retained within the lumen of the
aorta stent graft. The tubular portion is affixed at a sufficient
depth such that the flaring portion is maintained against an inside
wall of the aorta stent graft to thereby bias the aorta stent graft
toward the branch vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention can be better understood with reference to the
following drawings and description. The components in the figures
are not necessarily to scale, emphasis instead being placed upon
illustrating the principles of the invention. Moreover, in the
figures, like referenced numerals designate corresponding parts
throughout the different views.
[0020] FIG. 1 shows an abdominal aorta with an aorta stent graft
having fenestrations aligned with the renal arteries;
[0021] FIG. 1A is a partial side cross-section of the aorta stent
graft of FIG. 1 having a branch vessel prosthesis.
[0022] FIG. 1B is a top cross-sectional view of the aorta stent
graft of FIG. 1 having a branch vessel prosthesis.
[0023] FIG. 2A illustrates a stent graft positioned in the thoracic
aorta and having fenestrations aligned with the left subclavian
artery and the left common carotid artery.
[0024] FIG. 2B shows the aorta stent graft of FIG. 2A with a branch
vessel prosthesis extending into the subclavian artery.
[0025] FIG. 3 is a partial illustration of the abdominal aorta with
an aorta stent graft placed in an iliac artery and having a branch
vessel prosthesis extending into the hypogastric artery.
[0026] FIG. 4A is a perspective view of a branch vessel prosthesis
having a flareable portion and a tubular portion.
[0027] FIG. 4B is a perspective view of the branch vessel
prosthesis of FIG. 4A placed in a fenestration of an aorta stent
graft.
[0028] FIG. 4C is perspective view of a partially deployed branch
vessel prosthesis.
[0029] FIG. 5 is perspective view of a branch vessel prosthesis
have a reinforcement ring at its proximal end.
[0030] FIG. 6 is a perspective view of the branch vessel prosthesis
of FIG. 5 in a partially deployed state.
[0031] FIG. 7 is a partial cross-sectional view of a branch vessel
prosthesis having a reinforcement ring at its proximal end and an
aorta stent graft fenestration having a reinforcement ring about
its circumference.
[0032] FIG. 8 is illustrates a branch vessel prosthesis comprising
a helical coil stent graft positioned in an aorta stent graft and
the branch vessel.
[0033] FIG. 9 shows the helical coil branch vessel prosthesis of
FIG. 8 in greater detail.
[0034] FIG. 10 shows a branch vessel prosthesis having a flareble
stent portion.
[0035] FIGS. 11-14 are partial views of a stent configuration
having a bending portion for use with a branch vessel
prosthesis.
[0036] FIGS. 15-16 are partial views of alternative bending
portions.
[0037] FIG. 17 shows a branch vessel prosthesis in which a portion
of the stent forms a proximal bulge.
[0038] FIG. 18 is a partial cross-sectional view of a branch vessel
prosthesis positioned in an aorta stent graft having a flaring
attachment mechanism.
[0039] FIG. 19 shows the attachment mechanism of FIG. 18.
[0040] FIG. 20 is a perspective view of branch vessel prosthesis
having an inverted flaring portion.
[0041] FIG. 21 is a cross-sectional view of the branch vessel
prosthesis of FIG. 20 placed in an aorta stent graft and branch
vessel.
[0042] FIG. 22 is an exploded perspective view of an introducer
system that may be used to deploy an aorta stent graft or a branch
vessel prosthesis.
[0043] FIG. 23 is a partial side view of an introducer for a branch
vessel prosthesis.
[0044] FIG. 24A-C are cross-sectionals views of the deployment of a
branch vessel prosthesis in an aorta stent graft.
[0045] FIG. 25 is a cross-sectional view of a positional indicator
system for use with a branch vessel prosthesis.
[0046] FIGS. 26A-E illustrate a balloon catheter deployment system,
including a positional indicator system, that may be used to deploy
a branch vessel prosthesis.
[0047] FIGS. 27A-H illustrate balloon deployment systems that may
used to deploy or expand a branch vessel prosthesis.
DETAILED DESCRIPTION OF THE INVENTION
[0048] To help understand this description, the following
definitions are provided with reference to terms used in this
application.
[0049] Throughout this specification and in the appended claims,
when discussing the application of this invention to the aorta or
other blood vessels, the term "distal" with respect to such a
device is intended to refer to a location that is, or a portion of
the device that when implanted is, further downstream with respect
to blood flow; the term "distally" means in the direction of blood
flow or further downstream. The term "proximal" is intended to
refer to a location that is, or a portion of the device that when
implanted is, further upstream with respect to blood flow; the term
"proximally" means in the direction opposite to the direction of
blood flow or further upstream.
[0050] The term "prosthesis" means any replacement for a body part
or function of that body part. It can also mean a device that
enhances or adds functionality to a physiological system. As used
herein, "prosthesis" includes a stent, a graft, and/or a stent
graft.
[0051] The term "endoluminal" describes objects that are found or
can be placed inside a lumen in the human or animal body. A lumen
can be an existing lumen or a lumen created by surgical
intervention. This includes lumens such as blood vessels, parts of
the gastrointestinal tract, ducts such as bile ducts, parts of the
respiratory system, etc. An "endoluminal prosthesis" is thus a
prosthesis that can be placed inside one of these lumens. A stent
graft is a type of endoluminal prosthesis.
[0052] The term "stent" means any device or structure that adds
rigidity, expansion force or support to a prosthesis. In some
cases, the stent, by itself, is the prosthesis. A stent may be
self-expanding, balloon expandable or may have both
characteristics. A zigzag stent is a stent that has alternating
struts and peaks (i.e., bends) and defines a generally cylindrical
space. A "Gianturco Z stent" is a type of self-expanding zigzag
stent. However, variety of other stent configurations are
contemplated by use of the term stent.
[0053] The term "stent graft" is intended to refer to a prosthesis
comprising a stent and a graft material associated therewith that
forms a lumen through at least part of its length.
[0054] The term "branch vessel" refers to a vessel that branches
off from a main vessel. The "branch vessels" of the thoracic and
abdominal aorta include the celiac, inferior phrenic, superior
mesenteric, lumbar, inferior mesenteric, middle sacral, middle
suprarenal, renal, internal spermatic, ovarian (in the female),
innominate, left carotid, and left subclavian arteries. As another
example, the hypogastric artery is a branch vessel to the common
iliac, which is a main vessel in this context. Thus, it should be
seen that "branch vessel" and "main vessel" are relative terms.
[0055] The term "aorta stent graft" refers to a prosthesis that
shunts blood through a main vessel. An "aorta stent graft lumen"
runs through the aorta stent graft.
[0056] The term flaring, as used herein, encompasses the terms
flared and flareable.
[0057] An aorta stent graft may be deployed within a body lumen
having branch vessels to repair the body lumen. In order to prevent
the occlusion of branch vessels, some accommodation may be
necessary to preserve flow into those vessels. Thus, for those
situations, it is desireable to provide branch vessel prostheses
extending from the aorta stent graft into the branch vessels in
order to preserve flow to those branch vessels. The present
invention provides a branch vessel prosthesis, for use with an
aorta stent graft defining a lumen and having a fenestration
aligned with a branch vessel, including a flaring portion and a
tubular portion. The flaring portion is retained within the lumen
of the aorta stent graft and the tubular portion passes through the
fenestration and into the branch vessel.
[0058] FIG. 1 illustrates a bifurcated aorta stent graft 1 that
having a proximal end 2 and a distal end 3, that has been
positioned in an abdominal aortic aorta 4 from a point above the
renal arteries 5 to a point where the stent graft 1 bifurcates into
the iliac arteries 6.
[0059] As shown in FIG. 1, the aorta stent graft 1 includes two
fenestrations 7 or holes in the stent graft 1 that are aligned with
the renal arteries 5, which may accommodate branch vessel
prostheses as described further below. In FIG. 1, the aorta 4 has
an aneurysm 8 between the renal arteries 5 and the iliac arteries 6
and another aneurysm 9 in the region of the renal arteries 5. The
aorta stent graft 1 may include an attachment member 10 for
securing the aorta-stent graft 1 to an aortic side wall to prevent
migration of the stent graft 1 after it has been placed. The
attachment member may comprise a zig zag stent extending from the
proximal end 2.
[0060] FIG. 1A is a partial side view of the aorta stent graft 1 of
FIG. 1 having a branch vessel prosthesis 11 secured within a
fenestration 7 of the aorta stent graft 1 and extending into a
renal artery 5. FIG. 1B is a top cross-sectional view of the aorta
stent graft 1 and the branch vessel prosthesis 11 of FIGS. 1A and
1B. As shown in FIGS. 1A and 1B, a proximal end 12 of the branch
vessel prosthesis 11 extends through the fenestration 7 of the
aorta stent graft 1 and the aortic ostium 13 into the side branch
vessel/renal artery 5, thereby bypassing the aneurysm 9 located in
the area of the renal arteries 5.
[0061] FIGS. 2A and 3 illustrate aorta stent grafts 1 having
fenestrations 7 that are aligned with various vessels that branch
off of the aorta 4. For example, FIG. 2A illustrates an aorta stent
graft 1 that has been placed within the thoracic aorta 14 that has
fenestrations 7 aligned with the left subclavian artery 15 and the
left common carotid artery 16. FIG. 2B shows the aorta stent graft
1 of FIG. 2A having a branch vessel prosthesis 11 extending from
within the fenestration 7 of the stent graft 1 through to the left
subclavian artery 15.
[0062] FIG. 3 is a partial illustration of the bifurcated aortic
vessel of FIG. 1 at the point of the bifurcation 17 into the iliac
arteries 6. As shown, a stent graft 1, having a generally tubular
shape, is disposed within the left iliac artery 6' with a
fenestration 7 aligned with the hypogastric artery 18. A branch
vessel prosthesis 11 extends from the stent graft 1 through the
fenestration 7 and into the hypogastric artery 18.
[0063] Both the aorta-stent graft 1 and the branch vessel
prosthesis 11 may be formed from a biocompatible woven or non-woven
fabric or other graft material, and make include one or more
external and internal stents, for example, as shown in FIG. 1. For
example, along the length of the aorta stent graft 1 and/or the
branch vessel prosthesis 11, there may be a number of
self-expanding zigzag stents 19 such as Gianturco Z stents on the
outside of the body, as shown in FIG. 1. At one or both ends 2, 3
of the aorta stent graft 1 there may be an internal zigzag stent 20
which helps seal against a vascular wall or an interconnecting
module. However, the configuration of the stents is not limited to
zig zag stents, as any stent configuration known to those in the
art can be used.
[0064] The outer surface of the tubular body at the ends 2, 3 may
present an essentially smooth outer surface that can engage and
seal against the wall of the aorta or an adjoining prosthetic
module when it is deployed. The internal stent 20 may be comprised
of struts with bends at each end of the struts. Barbs may extend
from the struts or the bends through the graft material to engage
the surrounding vessel wall to prevent distal movement of the aorta
stent graft 1 that may be caused by pulsatile blood flow through
the aorta stent graft 1. The stents 19, 20 may be joined to the
graft material by any known means. Preferably, the stents 19, 20
may be joined to the graft material by stitching, for example by
using a monofilament or braided suture material. The branch vessel
prosthesis may comprise a stent or series of stents alone or with
graft material.
[0065] The stents may comprise a balloon-expandable stent or a
self-expanding stent. The self expanding stent can include
stainless steel, materials with elastic memory properties, such as
NITINOL, or any other suitable material. The branch vessel
prosthesis 11 may be formed from self-expanding stents such as
Z-STENTS.RTM.. Z-STENTS.RTM. are available from Cook, Incorporated,
Bloomington, Ind. USA. The balloon expandable stent portion
(typically 316LSS, CoCr, Etc.) can also include a shape memory
material having self expanding portion(s) such as titanium,
magnesium, nickel, alloys and the like.
[0066] Graft material may include a film, a coating, a sheet of
biocompatible fabrics, non-woven materials or porous materials.
Examples of biocompatible polymers from which porous sheets can be
formed include polyesters, such as poly(ethylene terephthalate),
polylactide, polyglycolide and copolymers thereof; fluorinated
polymers, such as polytetrafluoroethylene (PTFE), expanded PTFE and
poly(vinylidene fluoride); polysiloxanes, including polydimethyl
siloxane; and polyurethanes, including polyetherurethanes,
polyurethane ureas, polyetherurethane ureas, polyurethanes
containing carbonate linkages and polyurethanes containing siloxane
segments. In addition, materials that are not inherently
biocompatible may be subjected to surface modifications in order to
render the materials biocompatible. Examples of surface
modifications include graft polymerization of biocompatible
polymers from the material surface, coating of the surface with a
crosslinked biocompatible polymer, chemical modification with
biocompatible functional groups, and immobilization of a
compatibilizing agent such as heparin or other substances. Thus,
any polymer that may be formed into a porous sheet can be used to
make a graft material, provided the final porous material is
biocompatible. Polymers that can be formed into a porous sheet
include polyolefins, polyacrylonitrile, nylons, polyaramids and
polysulfones, in addition to polyesters, fluorinated polymers,
polysiloxanes and polyurethanes as listed above. Preferably the
porous sheet is made of one or more polymers that do not require
treatment or modification to be biocompatible.
[0067] The graft material may include a biocompatible polyurethane.
Examples of biocompatible polyurethanes include THORALON.RTM.
(Thoratec, Pleasanton, Calif.), BIOSPAN.RTM., BIONATE.RTM.,
ELASTHANE.TM., PURSIL.TM. and CARBOSIL.TM. (Polymer Technology
Group, Berkeley, Calif.). As described in U.S. Patent Application
Publication No. 2002/0065552 A1, incorporated herein by reference,
THORALON.RTM. is a polyetherurethane urea blended with a
siloxane-containing surface modifying additive. Specifically, the
polymer is a mixture of base polymer BPS-215 and an additive
SMA-300.
[0068] The graft material may also include extracellular matrix
materials. The "extracellular matrix" is typically a collagen-rich
substance that is found in between cells in animal tissue and
serves as a structural element in tissues. Such an extracellular
matrix is preferably a complex mixture of polysaccharides and
proteins secreted by cells. The extracellular matrix can be
isolated and treated in a variety of ways. Following isolation and
treatment, it is referred to as an "extracellular matrix material,"
or ECMM. ECMMs may be isolated from submucosa (including small
intestine submucosa), stomach submucosa, urinary bladder submucosa,
tissue mucosa, renal capsule, dura mater, liver basement membrane,
pericardium or other tissues.
[0069] Purified tela submucosa, a preferred type of ECMM, has been
previously described in U.S. Pat. Nos. 6,206,931, 6,358,284 and
6,666,892 as a bio-compatible, non-thrombogenic material that
enhances the repair of damaged or diseased host tissues. U.S. Pat.
Nos. 6,206,931, 6,358,284 and 6,666,892 are incorporated herein by
reference. Purified submucosa extracted from the small intestine
("small intestine submucosa" or "SIS") is a more preferred type of
ECMM for use in this invention. Another type of ECMM, isolated from
liver basement membrane, is described in U.S. Pat. No. 6,379,710,
which is incorporated herein by reference. ECMM may also be
isolated from pericardium, as described in U.S. Pat. No. 4,502,159,
which is also incorporated herein by reference.
[0070] In addition to xenogenic biomaterials, such as SIS,
autologous tissue can be harvested as well. Additionally Elastin or
Elastin Like Polypetides (ELPs) and the like offer potential as a
material to fabricate the covering or frame to form a device with
exceptional biocompatibility. Another alternative would be to use
allographs such as harvested native valve tissue. Such tissue is
commercially available in a cryopreserved state. In addition, a
bare metal stent or a covered stent could be coated with an
anti-restenotic agent, such as paclitaxel, sirilomis or other
equivalent. In addition, the graft can be coated with an
anti-thrombogenic agent, such as heparin.
[0071] The graft material may be attached to the stent by any means
known, for example, the graft material may be attached to the stent
by sutures. The graft material also may be affixed to the stent by
dipping the stent in a liquefied polymer and allowing the polymer
to solidify into a film. The liquefied polymer may be a molten
polymer or a polymer or pre-polymer before curing or cross-linking
occurs.
[0072] Various configurations for the branch vessel prosthesis 11
are illustrated in FIGS. 4-21. The branch vessel prosthesis also
may have the structure described in pending U.S. application Ser.
No. 10/267,576, filed Oct. 8, 2002, which is hereby incorporated by
reference, or U.S. Pat. Nos. 5,718,713, 5,741,327, 5,746,691,
5,843,175, 5,868,782, 6,042,606, 6,299,635 each of which is hereby
incorporated by reference.
[0073] The branch vessel prosthesis 11 may be a stent, a series of
stents, formed from a piece of graft material, or comprise a stent
graft. One end of the branch vessel prosthesis 11 is intended to be
placed within the lumen of the aorta stent graft 1 through a
fenestration 7 in the stent graft 1 as discussed in more detail
below and the other end is intended to be placed in a branch
vessel. The branch vessel prosthesis 11 is preferably of a size and
shape suitable for the branch vessel in which it is to be deployed.
Thus, the size and shape of the branch vessel prosthesis 11 may be
dictated by the particular anatomy of the patient to be treated and
the location where the branch vessel prosthesis 11 is to be
place.
[0074] The branch vessel prosthesis 11 permits the repair of a
diseased or compromised vessel without obstructing blood flow in
other portions of the vasculature and conforms to a fenestration 7
of the aorta stent graft 1 without causing swirling in the blood
flow and creating the potential for thrombi formation. The branch
vessel prosthesis 11 also permits access to all portions of the
branch vessel in the event of further interventional treatment.
Additionally, the branch vessel prosthesis 11 provides a secure
seal between branch vessel prosthesis 11 and a branch vessel, while
assisting in anchoring the branch vessel prosthesis 11 to a main
vessel, such as an aorta.
[0075] FIGS. 4A-C generally show a branch vessel prosthesis 11
defining a lumen 34 and having a proximal end 30, a distal end 32,
a flaring portion 36, and a tubular portion 33. As described above,
the branch vessel prosthesis 11 may comprise graft material and
have one or more stents fastened to the inner, the outer, or both
surfaces. The distal end 32 may include an internal stent 40 having
barbs 42 projecting through the graft material for securement to
the branch vessel and to prevent migration of the device after
placement. The proximal end 30 or flaring portion 36 may also be
provided with attachment mechanism, such as barbs 42, for securing
the flaring portion 36 within the aorta stent graft 1.
[0076] Preferably, at least a part of the flaring portion 36 has a
diameter greater than the diameter of the fenestration 7.
Positional indicators 43, such as radiopaque markers, may be
attached to or integral with the stent and/or graft material, and
may be placed at positions on the branch vessel prosthesis 11 to
indicate the proximal end 30, the flaring portion 36 and/or the
distal end 32. Preferably, a positional marker 43 is placed so as
to indicate that portion of the branch vessel prosthesis 11 that
generally aligns with the fenestration 7.
[0077] During deployment, the barbs 42 may be enclosed in an endcap
44 of the delivery system 46, as shown in FIG. 4C. As described
above, and shown in FIG. 4B, the branch vessel prosthesis 11 is
intended to provide a conduit from previously placed aorta stent
graft 1 and a branch vessel. The flaring portion 36 extends through
the fenestration 7 of the aorta stent graft 1 while the tubular
portion 33 extends into the branch vessel.
[0078] FIGS. 5-7 illustrate another embodiment of a branch vessel
prosthesis 11. FIG. 5 is a side perspective view of a branch vessel
prosthesis 11 in its deployed state. FIG. 6 is a side perspective
view of a branch vessel prosthesis 11 in a partially deployed
state. FIG. 7 is a partial view in cross-section of an aorta stent
graft 1 having a fenestration 7 and a branch vessel prosthesis 11
secured within the aorta stent graft 1 through the fenestration 7.
The branch vessel prosthesis illustrated in FIGS. 5-7 includes
mating reinforcements 38, 60 for securing the branch vessel
prosthesis 11 within the aorta stent graft 1.
[0079] As shown in FIG. 5, the branch vessel prosthesis 11 may be a
tubular stent graft. The branch vessel prosthesis 11 includes a
proximal end 30, a distal end 32, a tubular portion 33, a lumen 34
between the proximal end 30 and the distal end 32, a flaring
portion 36, and a reinforcement ring 38 adjacent the proximal end
30. The reinforcement ring 38 may be attached to the flaring
portion 36 of the branch vessel prosthesis 11 around its
circumference. The reinforcement ring 38 is adapted to engage a
second reinforcement ring 60 associated the fenestration 7, as
shown in FIG. 7 and discussed in detail with reference to that
figure below.
[0080] As shown in FIG. 5, the distal end 32 of the branch vessel
prosthesis may also be flared to secure the distal end 32 of the
branch vessel prosthesis 11 in the branch vessel. The flaring
portion 36 and reinforcement ring 38 are deployed within the lumen
of an aorta stent graft 1 and retained in the lumen of the stent
graft 1. The tubular portion 33 is configured to be received
through a fenestration 7. Thus, the remainder of the branch vessel
prosthesis 11, the tubular portion 33, is configured to be received
and retained within a branch vessel. The distal end 32 may include
an internal stent 40 having barbs 42 projecting through the graft
material for securement to the branch vessel. One or more external
stents 29 may also be secured to the graft material as shown in
FIG. 5.
[0081] FIG. 6 shows the branch vessel prosthesis 11 of FIG. 5 in a
partially deployed state. The branch vessel prosthesis 11 is shown
mounted on an introduction system 50 comprising an inner cannula 52
on which the branch vessel prosthesis 11 mounted. The distal end 32
including the barbs 42 enclosed within end cap 44 to permit adjust
the placement of the branch vessel prosthesis 11 without causing
damage to the vessel wall.
[0082] In operation, the introducer system for the branch vessel
prosthesis is introduced into the lumen of a previously positioned
aorta stent graft. The tubular portion 33 of the branch vessel
prosthesis is introduced through the fenestration and into the
branch vessel and partially deployed, leaving the barbs enclosed
until proper placement is ensured. Thereafter the flaring portion
of the branch vessel prosthesis 11 is properly aligned with the
fenestration and deployed within the lumen of the aorta stent graft
1. Then the barbed distal end of the tubular portions 33 is
released and the prosthesis is placed. If the tubular portion 33
and flaring portion 36 are self expandable, one or more molding
balloons may be used to further fit the prosthesis in the aorta
stent graft lumen and branch vessel.
[0083] Alternatively, the branch vessel prosthesis 11 may comprise
balloon expandable stents and may be introduced on a balloon
expansion catheter, as described more fully herein. In that case,
the flaring portion 36 is flared and the tubular portion 33 is
expanded by one or more balloons. In yet another embodiment, the
flaring portion 36 is balloon expandable and the tubular portion 33
is self expandable. Other combinations of these types of stents are
contemplated as well.
[0084] FIG. 7 shows the placement of the proximal end 30 of the
branch vessel prosthesis 11 within the lumen 34 of the aorta stent
graft 1. The aorta stent graft 1 includes a reinforcement ring 60
positioned around the fenestration 7 wherein the fenestration 7 is
substantially aligned with a branch vessel when deployed. As shown
in FIG. 7, the flaring portion 36 retains the proximal end 30 of
the branch vessel prosthesis 11 within the aorta stent graft 1. The
tubular portion 33 extends through the fenestration 7 and into the
branch vessel 5 when deployed. Preferably, the branch vessel
prosthesis reinforcement ring 60 and the flaring portion 36, have a
diameter equal or greater than the diameter of the aorta stent
graft reinforcement ring 38.
[0085] In a preferred embodiment, both the flaring portion 36 and
the branch vessel prosthesis reinforcement ring 38 have a diameter
greater than the aorta stent graft reinforcement ring 60. In this
embodiment, the branch vessel prosthesis reinforcement ring 38
diameter is greater than the aorta stent graft reinforcement ring
diameter so that the flaring portion 36 seals against the
fenestration 7 of the aorta stent graft 1 as the branch vessel
prosthesis reinforcement ring 38 and the aorta stent graft
reinforcement ring 60 engage. Preferably, the branch vessel
prosthesis reinforcement ring 38 and the aorta stent graft
reinforcement ring 60 at least partially abut.
[0086] The aorta stent graft reinforcement ring may be secured to a
surface of graft material located on the aorta stent graft. For
example, the aorta stent graft reinforcement ring may be secured to
an inner surface of the aorta stent graft by sutures, adhesives or
other means. The branch vessel prosthesis reinforcement ring also
may be secured to a surface of graft material located on the branch
vessel prosthesis. The branch vessel prosthesis reinforcement ring
may be secured to an outer surface of the flaring portion by the
same means.
[0087] In one preferred embodiment shown in FIG. 7, both rings 38,
60 may be partially or wholly encased in the graft material. When a
penetrable material, such as graft material is used, barbs 42 (as
shown in FIG. 7), or other attachment mechanisms may be provided on
one or more of the reinforcement rings to further secure the rings.
At least one of the rings may be of resilient material to allow
compaction until deployment. In addition, at least one of the rings
may be made of a shape memory alloy.
[0088] The reinforcement rings may be shaped and sized so as to
interlock with each other when deployed. In alternate embodiments,
the reinforcement rings may comprise hooks or other mechanical
fastening means. For example, one of the reinforcement rings can
include a surface with loops and the other of the reinforcement
rings can include a surface with hooks, such as in the material
known as Velcro.RTM., so as to facilitate attachment of the two
reinforcement rings to each other when deployed. In another
example, one of the reinforcement rings can include tabs and the
other reinforcement ring can include holes for receiving the tabs
to facilitate attachment of the two reinforcement rings to each
other when deployed. In another embodiment, at least one of the
reinforcement rings comprises a magnetic material so that the
reinforcement rings are drawn together by magnetic force when
deployed.
[0089] At least one of the reinforcement rings can include a
surface of a sealing material to facilitate a seal between the
aorta stent graft and the branch vessel prosthesis. In addition,
both of the reinforcement rings can comprise a surface of a sealing
material to facilitate a seal between the aorta stent graft and the
branch vessel prosthesis. For example, one of the reinforcement
rings can include a surface with a biocompatible adhesive to
facilitate attachment of the two reinforcement rings to each other
when deployed.
[0090] As with the branch vessel prosthesis 11 described in FIGS.
4A-C, positional indicators may be located at any point on the
branch vessel prosthesis 11. In particular, positional indicators
43, such as radiopaque or other types of markers that would be
visible to the doctor during deployment, may be located at the
proximal end 30, the distal end 32 and the point of the graft
intended to align with the fenestration of the aorta stent graft
1.
[0091] The branch vessel prosthesis 11 of FIGS. 5-6 is deployed,
for example, by introducing the prosthesis 11 into an aorta stent
graft 1 such that the flaring portion 36 retains the proximal end
of the branch vessel prosthesis in the aorta stent graft, the
tubular portion extends through the fenestration 7 and into the
branch vessel 5, and the reinforcement rings 38, 60 engage one
another.
[0092] Another branch vessel prosthesis 11 is shown in FIGS. 8 and
9. The branch vessel prosthesis 11 includes a generally helical
coiled stent 70. Graft material 62 may be affixed thereto to form a
branch vessel lumen 34. For example, when the aneurysm extends into
the branch vessel, the helical coil stent is preferably covered
with graft material. However, if the aneurysm stops short of the
branch vessel, a bare helical coil stent may be used to maintain
patency of the branch vessel and/or to maintain alignment of the
aorta stent graft with the fenestration.
[0093] The graft material 62 may be attached to the helical coil
stent 70 by any means known, for example, the graft material may be
attached to the helical coil stent 70 by sutures. The graft
material 62 may be any of the materials described previously for
use as graft materials. For example, the graft material may be a
woven fabric or a polymer film. The graft material also may be
affixed to the helical coil stent 70 by dipping the stent in a
liquefied polymer and allowing the polymer to solidify into a film.
The helical coil may be composed of a metal wire.
[0094] The helical coiled stent 70 may be an expandable stent
including a flaring portion 72 that is deployed within the aorta
stent graft 1, and a distal portion 74 that is deployed within the
branch vessel 5, such as a renal artery. The proximal end of the
branch vessel prosthesis 11 may form a seal with an inner surface
of the aorta stent graft 1 around the fenestration 7. The
fenestration 7 may include a reinforcement around the fenestration
7. For example, the reinforcement may be a reinforcement ring 60,
such as that shown and described previously with reference to FIG.
7. In this example, the reinforcement ring cooperates with at least
one full turn of the helical coil stent 70 at the proximal end 76
to form a seal between the aorta stent graft and the branch vessel
stent graft.
[0095] As shown in FIG. 8, the flaring portion 72 has a larger
diameter D2 than the distal portion diameter D1 and may assist to
pull the aorta stent graft 1 and the branch vessel 5 together. The
diameter of the turn of the coil 78 immediately adjacent an outer
surface of the fenestration 7 may also be greater than the diameter
of the fenestration 7 to thereby capture the fenestration 7 between
two adjacent coils. Preferably, the diameter of the turn of the
coil 78 is only slightly greater than the diameter of the
fenestration. In one embodiment, one full turn of the helical coil
stent at a proximal end has a diameter larger than the diameter of
the fenestration, and at least two full turns of the helical coiled
stent have a diameter smaller than the diameter of the
fenestration.
[0096] During deployment, at least two full turns of the helical
coil are passed through the fenestration into the branch vessel
while the proximal end with at least one full turn is retained in
the aorta stent graft 1 lumen. Positional indicators 43 may be
located on the proximal and distal most coils, as well as at the
location of the coil where the coiled stent flares, so as to
indicate the position of alignment with the fenestration. The coil
may also be provided with barbs 42 or some other fastening
mechanism, either on the coil itself or attached to graft material
to facilitate attachment of the device to the branch vessel wall
and/or the lumen of the aorta stent graft.
[0097] Another branch vessel prosthesis configuration is shown in
FIGS. 10-14. The branch vessel prosthesis 11 includes a stent
having a flaring proximal portion 36, a tubular section 33, a
bending portion 80 at a junction between the flareable proximal
portion 36 and the tubular portion 33 and a distal end 30, for use
with an aorta stent graft 1 defining a lumen and having a
fenestration aligned with a branch vessel. The branch vessel
prosthesis 11 preferably includes an expandable stent with a graft
material affixed thereto to form a branch vessel lumen. The tubular
portion 33 of the branch vessel prosthesis 11 may comprise a self
expanding stent while the flaring portion 36 may be a balloon
expandable stent. Alternatively, both portions may be balloon
expandable.
[0098] In one preferred embodiment, the proximal stent 82 is
connected to the proximal body stent 86 by the bending portion 80.
In another embodiment, when the stent is encapsulated in graft
material such as Thoralon, the proximal stent 82 may not be
directly connected to the proximal body stent 86 and the Thoralon
material between the proximal stent 82 and the proximal body stent
86 may form the bending portion 80.
[0099] In the embodiment of FIGS. 10-14, the branch vessel
prosthesis 11 is deployed such that the bending portion 80 is
aligned with a fenestration 7 of the aorta stent graft 1, the
flaring portion 36 resides within the lumen of the aorta stent
graft 1 and the tubular portion 33 resides in the branch vessel.
Upon deployment, the flaring of the flaring portion 36 is
preferably accomplished by a balloon that facilitates bending of
the bending portion 80.
[0100] As shown in FIGS. 10-14, the branch vessel prosthesis 11 may
comprise a multi-cell stent structure having a proximal cell 82
intended to be the cell closest to the ostium or branch vessel
entrance. The proximal cell 82 is connected to a plurality 83 of
interconnected body cells 84. Each cell is a substantially circular
ring comprising an endless undulating pattern.
[0101] As shown in FIGS. 12-14, the plurality 83 of interconnected
body cells 84 forms the tubular portion 33 of the branch vessel
prosthesis 11 and includes a proximal body-cell 86 and a distal
body cell 88. When deployed, the proximal body cell 86 is the body
cell closest to the fenestration 7 (and thus the ostium of the main
vessel) and is connected to the proximal cell 82. The distal body
88 cell is the body cell farthest from the fenestration 7 (and thus
the ostium of the main vessel).
[0102] The proximal cell 82 is configured to flare-out in the
expanded configuration and forms the flaring portion 36 of the
branch vessel prosthesis 11. The proximal cell configuration is
contemplated to form the flaring portion 36. For example, the
proximal cell 82 may be configured with a wider cell width or a
longer strut length than the body cells 84. As shown in the Figures
the peaks 92 of the proximal cell 82 are unattached and free to
separate and thereby permit the flaring portion 36 to flare-out in
the expanded configuration. It should be noted that, as used herein
the term "peak" is interchangeable with the term "valley" and both
refer to a turn or bend in a stent cell.
[0103] Also, the frequency of the points of attachment between the
flaring portion 36 and the tubular portion 33 can be varied to
facilitate bending in the bending portion 80 of the branch vessel
prosthesis 11 in the expanded configuration. As shown in the 11-13,
each peak 94 along the distal edge of the proximal cell 82 is
connected to every other peak 96 along the proximal edge of the
proximal body cell 86. The flaring of the flaring portion 80 in the
expanded configuration may be decreased if each peak along the
distal edge of the proximal cell is connected to each peak along
the proximal edge of the proximal body cell. Conversely,
interconnecting each proximal cell peak to every third proximal
body cell peak increases the ability of the flaring portion to
flare in the expanded configuration.
[0104] Each of the plurality of interconnected body cells 84 may
have a shorter cell width and shorter strut length than the
proximal cell 82. Further, adjacent body cells 84 are connected to
each other by tie-bars 98 and/or connection members 100.
Flexibility along the body cells may be provided by altering the
shape of the connection members 100. Thus, the connection member
may comprise a "V" shape (FIGS. 10-14), an "S" shape (FIG. 15) or a
"W" shape (FIG. 16) to increase the flexibility of the tubular
portion 36 of the branch vessel prosthesis 11.
[0105] The bending portion 80 interconnects the proximal cell 82 to
the plurality of interconnected body cells 84. The bending portion
80 also forms a junction between the flaring portion 36 and the
tubular portion 33 of the branch vessel prosthesis 11. The bending
portion 80 minimizes the stress imposed by the flaring portion 36
on the tubular portion 33 in the expanded configuration by
providing a point of flexibility. Increasing the flexibility of
bending portion 80, increases the ability of the flaring portion 36
to flare-out in the expanded configuration. Flaring of the flaring
portion 36 is thus facilitated by the bending portion 80.
[0106] Multiple configurations of the bending portion 80 are
contemplated. In one embodiment, such as that depicted in FIGS. 10
and 11, the bending portion 80 includes metal struts having a
reduced diameter to facilitate bending at the bending portion 80.
For example, the bending portion 80 may undergo some form of
material reduction to enhance the flexibility between the proximal
cell 86 and the plurality 83 of body cells 84. Thus, as shown in
FIG. 12, the side edges 102, 104 of the bending portion 80 may
comprise a radius of curvature such that the bending portion 80
forms an hour-glass configuration. Increasing the radius of
curvature along the edges of the bending portion 80 increases the
flexibility of the bending portion 80. Similarly, the top and
bottom surfaces of the bending portion 80 may be polished to
enhance flexibility.
[0107] In other embodiments, the metal struts can be heat treated
or mechanically worked to facilitate bending at the bending
portion.
[0108] In still other embodiments, the configuration of the bending
portion 80 may be altered to enhance the flexibility. Thus, the
bending portion 80 may comprise a "V" shape (FIG. 11), an "S" shape
(FIG. 15), a "W" shape (FIG. 16) to increase the flexibility
between the flaring portion 36 and tubular portion 33 of the branch
vessel prosthesis 11.
[0109] In still yet other embodiments, the material at the bending
portion 80 may be more bendable than the material of the tubular
portion or flaring portion.
[0110] In still yet another embodiment, the bending portion 80 may
include fewer struts per unit area than the tubular portion 33 or
the flaring portion 36 to thereby facilitate bending at the bending
portion 80.
[0111] In the alternate embodiment shown in FIG. 17, using the
principles described above, the proximal body cell 86 may be
configured to expand or "bulge" 106 to secure the branch vessel
prosthesis 11 against the main vessel 4.
[0112] As with previous embodiments, positional indicators 43 may
be associated with the branch vessel prosthesis to facilitate
visualization of the prosthesis during and after deployment. For
example, positional indicators 43 may be on or associated with the
proximal cell 82 and the distal end 30. Preferably, at least one
positional indicator is positioned on or associated with the
bending portion 80 of the branch vessel prosthesis 11 to facilitate
alignment of the bending portion with the fenestration 7 of the
aorta stent graft 1. As shown in FIGS. 10-14, for example,
positional indicators 43 may be located at or associated with the
apices of the proximal cell 82, located at or associated with the
bending portion 80, and located at or associated with the distal
end 86.
[0113] The branch vessel prosthesis 11 of this embodiment may also
be provided with barbs or other fastening mechanisms, either on the
stent itself or attached to graft material to facilitate attachment
of the device to the branch vessel wall and/or the lumen of the
aorta stent graft 1. For example, the proximal cell 82 may be
provided with barbs 42, as shown in FIG. 13.
[0114] Another branch vessel prosthesis configuration is shown in
FIGS. 18 and 19. As shown, the branch vessel prosthesis 11 has a
flaring portion 36 and a tubular portion 33 with an anchoring
device 200, such that when deployed, the flaring portion 36 is
located within the lumen of the aorta stent graft 1 and the tubular
portion 33 passes through the fenestration 7 and into the branch
vessel 5, with the anchoring device 200 affixing the position of
the tubular portion 202 within the branch vessel 5. Upon
deployment, the system further allows the tubular portion 33 to be
inserted and affixed a predetermined depth into the branch vessel 5
such that the flaring portion 36 is maintained against an inside
wall of the aorta stent graft 1 to thereby bias the aorta stent
graft 1 toward the branch vessel 5.
[0115] The flaring portion 36 is configured to engage a
fenestration 7 of the aorta stent graft 1. The anchoring device 200
comprises securement arms 202. that extend within the fenestration
7 of the aorta stent graft 1 and secure the branch vessel stent
graft 11 against the fenestration 7 of the aorta stent graft 1 and
the ostium of the branch vessel 5. In this example, the branch
vessel prosthesis 11 includes metal struts in the flaring portion
36 that form an acute angle with the tubular portion 33 such that
when the tubular portion 36 is inserted a predetermined depth into
the branch vessel 5, the flaring portion 36 is maintained against
an inside wall of the aorta stent graft 1 to thereby bias the aorta
stent graft 1 toward the branch vessel 5. When deployed, the metal
struts are curved through than arc of more than 90 degrees with
respect to the tubular portion 33. For example, when deployed, the
metal struts may be curved through an arc of about 180 degrees with
respect to the tubular portion.
[0116] As shown in FIGS. 18-19, the anchoring device 200 may
comprise a zig zag portion 204 with the securement arms 202
extending from the proximal apices 206 of the zig zag portion 204.
The proximal ends 208 of the securement arms 202 may form an arc or
hook 210 at the ends 208 of the arms 202 for anchoring the flaring
portion 36 of the branch vessel prosthesis 11 with the aorta stent
graft 1. Anchoring barbs 42 may provided at the distal apices 214
of the zig zag portion 204. Positional indicators 43 Radiopaque or
other visual markers 43 may also be provided at the distal apices
212, the proximal ends 208 of the arms 208 to facilitate viewing of
the branch vessel prosthesis 11 during and after deployment.
[0117] Another branch vessel configuration is shown in FIGS. 20-21.
In this configuration the flaring portion 300 that is configured to
engage a fenestration 7 of the aorta stent graft 1 is inverted
relative to the flaring portions of other configurations shown
here. In other words, in this configuration, as shown in FIG. 21,
the flaring portion 300 forms an acute angle with respect to the
tubular portion 302, and forms a seal with an inner surface of the
lumen of the aorta stent graft 1. As shown in FIG. 21, the flaring
portion 300 extends through the fenestration 7 of the aorta stent
graft 1 and secures the branch vessel prosthesis 11 against the
aorta stent graft 1.
[0118] In this configuration, positional indicators 304 may be
located at or associated with the proximal end 306, the distal end
308 and/or the rim 310 of the flaring portion 300. Additionally,
one or more fastening barbs 312 may be placed circumferentially
about the rim the rim 310 of the flaring portion 300 to secure the
rim 310 to the aorta stent graft 1 as shown in Figures. Additional
barbs 314, may be included on the tubular portion 316 of the branch
vessel prosthesis 11 to secure the tubular portion 316 to the
branch vessel 5. As shown in the Figures, the additional barbs 314
may be circumferentially placed about the tubular portion 316 in
one or more sets of the additional barbs 314.
[0119] The Introducer
[0120] FIG. 22 shows a self-expanding aorta stent graft 1, and an
endovascular deployment system 500, also known is an introducer
100, that may be used to deploy the aorta stent graft 1 in a main
vessel, such as the abdominal or thoracic aorta, of a patient
during a medical procedure. These items are each described in
greater detail in PCT application WO 98/53761. The same deployment
system 500 may be used for the deployment the branch vessel
prosthesis and, thus, FIG. 22 is fully applicable thereto.
[0121] The aorta stent graft 1 has an expandable tubular portion
502 having a proximal end 504, and a distal end 506. The aorta
stent graft 1 comprises a tubular graft material, such as woven
polyester, with self-expanding stents 506 attached thereto. The
self-expanding stents 506 cause the aorta stent graft 1 to expand
following its release from the introducer 500. The aorta stent
graft 1 also includes a self-expanding proximal stent 508 that
extends from its proximal end 504. The proximal stent 508 may have
distally extending barbs 510. When it is released from the
introducer 500, the proximal stent 508 anchors the barbs 510, and
thus the proximal end 504 of the aorta stent graft 1, to the lumen
of the patient. The proximal end 504 of the aorta stent graft 1 is
provided with one or more fenestrations 512 that are intended to
align with a branch vessel.
[0122] The introducer 500 includes an external manipulation section
514, a distal attachment region 516 and a proximal attachment
region 518. The distal attachment region 516 and the proximal
attachment region 518 secure the distal and proximal ends of the
aorta stent graft 1, respectively. During the medical procedure to
deploy the aorta stent graft 1, the distal and proximal attachment
regions 516 and 518 will travel through the lumen to a desired
deployment site. The external manipulation section 514, which is
acted upon by a user to manipulate the introducer, remains outside
of the patient throughout the procedure.
[0123] The proximal attachment region 518 of the introducer 500
includes a cylindrical sleeve 520. The cylindrical sleeve 520 has a
long tapered flexible extension 522 extending from its proximal
end. The flexible extension 522 may be substantially aligned with a
longitudinal axis of the introducer 500, as shown in FIG. 22.
Alternatively, flexible extension 522 may curve to accommodate
curves or turns in a patient's anatomy, as shown in FIGS. 23 and
24A-B. The flexible extension 520 has an internal longitudinal
aperture (not shown). This longitudinal aperture facilitates
advancement of the tapered flexible extension 522 along an
insertion wire (not shown). The longitudinal aperture also provides
a channel for the introduction of medical reagents. For example, it
may be desirable to supply a contrast agent to allow angiography to
be performed during placement and deployment phases of the medical
procedure.
[0124] A thin walled metal tube 524 is fastened to the extension
522. The thin walled metal tube 524 is flexible so that the
introducer 500 can be advanced along a relatively tortuous vessel,
such as a femoral artery, and so that the distal attachment region
516 can be longitudinally and rotationally manipulated. The thin
walled metal tube 524 extends through the introducer 500 to the
manipulation section 514, terminating at a connection means
526.
[0125] The connection means 526 is adapted to accept a syringe to
facilitate the introduction of reagents into the thin walled metal
tube 524. The thin walled metal tube 524 may be in fluid
communication with the apertures 528 of the flexible extension 522.
Therefore, reagents introduced into connection means 526 will flow
to and emanate from the apertures 528.
[0126] A plastic tube 530 is coaxial with and radially outside of
the thin walled metal tube 524. The plastic tube 530 is "thick
walled"--its wall is preferably several times thicker than that of
the thin walled metal tube 524. A sheath 532 is coaxial with and
radially outside of the plastic tube 530. The thick walled plastic
tube 530 and the sheath 532 extend distally to the manipulation
region 514.
[0127] During the placement phase of the medical procedure, the
aorta stent graft 1 is retained in a compressed condition by the
sheath 532. The sheath 532 extends distally to a gripping and
hemostatic sealing means 534 of the external manipulation section
526. During assembly of the introducer 500, the sheath 532 is
advanced over the cylindrical sleeve 520 of the proximal attachment
region 518 while the aorta stent graft 1 is held in a compressed
state by an external force. A distal attachment (retention) section
536 is coupled to the thick walled plastic tube 530. The distal
attachment section 536 retains a distal end 538 of the aorta stent
graft 1 during the procedure. Likewise, the cylindrical sleeve 520
retains the proximal stent 508.
[0128] The distal end 538 of the aorta stent graft 1 is retained by
the distal attachment section 536. The distal end 538 of the aorta
stent graft 1 has a loop (not shown) through which a distal trigger
wire (not shown) extends. The distal trigger wire extends through
an aperture (not shown) in the distal attachment section 536 into
an annular region between the thin walled tube 524 and the thick
walled tube 530. The distal trigger wire extends through the
annular space to the manipulation region 514. The distal trigger
wire exits the annular space at a distal wire release mechanism
540.
[0129] The external manipulation section 514 includes a hemostatic
sealing means 534. The hemostatic sealing means 534 includes a
hemostatic seal (not shown) and a side tube 542. The hemostatic
sealing means 534 also includes a clamping collar (not shown) that
clamps the sheath 532 to the hemostatic seal, and a silicone seal
ring (not shown) that forms a hemostatic seal around the thick
walled plastic tube 530. The side tube 542 facilitates the
introduction of medical reagents between the thick walled tube 530
and the sheath 532.
[0130] A proximal portion of the external manipulation section 514
includes a release wire actuation section that has a body 544. The
body 544 is mounted onto the thick walled plastic tube 530. The
thin walled tube 524 passes through the body 544. The distal wire
release mechanism 540 and the proximal wire release mechanism 546
are mounted for slidable movement onto the body 544.
[0131] The positioning of the proximal and distal wire release
mechanisms 540 and 544 is such that the proximal wire release
mechanism 540 must be moved before the distal wire release
mechanism 544 can be moved. Therefore, the distal end 538 of the
aorta stent graft 1 cannot be released until the proximal stent 508
has been released, and the barbs 510 have been anchored to the
lumen. Clamping screws 548 prevent inadvertent early release of the
aorta stent graft 1. A hemostatic seal (not shown) is included so
that the release wires can extend out through the body 544 without
unnecessary blood loss during the medical procedure.
[0132] A distal portion of the external manipulation section 514
includes a pin vise 550. The pin vise 550 is mounted onto the
distal end of the body 544. The pin vise 550 has a screw cap 552.
When screwed in, vise jaws (not shown) of the pin vise 550 clamp
against or engage the thin walled metal tube 524. When the vise
jaws are engaged, the thin walled tube 524 can only move with the
body 544, and hence the thin walled tube 524 can only move with the
thick walled tube 530. With the screw cap 552 tightened, the entire
assembly can be moved together as one piece.
[0133] A second introducer based on the same principles as the
introducer 500 described above may also be adapted so that it can
introduce a self-expanding branch vessel prosthesis by passing it
through the fenestration 512 in the aorta stent graft 562. As shown
in FIGS. 23 and 24A-C the introducer 500, having a curved flexible
extension 522, may be introduced into the lumen 560 of a previously
placed stent graft 562, and through the fenestration 564 into the
branch vessel 566. Once positioned properly, the sheath 532 may be
retracted, and the branch vessel prosthesis 568 expanded. Any barbs
570 located at the distal end 572 of the branch vessel prosthesis
568, remain in the end cap 574 until the prosthesis is properly
placed. The end cap 574 is released during deployment by a trigger
wire. Deployment of the branch vessel prosthesis is discussed in
further detail below.
[0134] As shown in FIG. 25, the introducer for the branch vessel
prosthesis 11 may include a positional indicator system 600, either
to compliment or to replace the positions indicator system on the
branch vessel prosthesis. As discussed above, positional indicators
may be placed on or associated with the branch vessel prosthesis 11
indicate various points on the branch vessel prosthesis 11. Also,
as previously discussed, one or more positional indicators may be
placed on or associated with the fenestration 7 of the aorta stent
graft 1. The system shown in FIG. 25 includes multiple positional
indicators on the introducer 602. A first positional indicator 604
is positioned on the introducer 602 and indicates the position of
the proximal end 606 of the branch vessel prosthesis 11. A second
positional indicator 608 is positioned on the introducer 602 and
indicates the position of that part of the branch vessel prosthesis
11 that is to be aligned with the fenestration 7 of the aorta stent
graft 1.
[0135] In FIG. 25, the second positional indicator 608 indicates
the bending portion 610 of the branch vessel prosthesis 11. A third
positional marker 612 is located on the introducer 602 and
indicates the position of branch vessel prosthesis 11 tubular
portion. A fourth positional indicator 614 may be positioned on or
near the end cap 616 to indicate the distal end of the branch
vessel prosthesis 11. Other positional indicators may be included
on the introducer at other locations as may be desired to
facilitate visualization of the branch vessel prosthesis 11 branch
vessel prosthesis during and after deployment. These positional
indicators may be used alone or in combination with positional
indicators on the branch vessel prosthesis 11 and/or the aorta
stent graft 1 to further enhance visualization.
[0136] In another aspect, where the branch vessel prosthesis 11 is
partially or entirely balloon expandable, a positional indicator
system is provided in connection with a balloon delivery system for
implanting the branch vessel prosthesis 11, as shown in FIGS.
26A-E. As shown in FIG. 26B, the delivery system 700 used to place
and deploy the branch vessel prosthesis 11 comprises a balloon
catheter 702 having a proximal portion 704 and a distal portion
706. As used with reference to the delivery catheter 702, the term
"proximal" refers to the direction or position closest to the user
and the term "distal" refers to the direction or position farthest
from the user. The balloon catheter further includes a
stent-loading area 708 located on a distal portion 706 of the
catheter 702. The stent-loading area 708 comprises a balloon 710
and a positional indicator system 711. The positional indicator
system includes one or more positional indicators that correspond
with various parts of the of the branch vessel prosthesis 11. For
example, the positional indicator system may include a first
positional indicator 712 on the catheter that corresponds with that
part of the branch vessel prosthesis 11 that is intended to align
with the fenestration 7 of the aorta stent graft 1. The system may
further include positional indicators 714, 715 that correspond with
the proximal distal ends of a branch vessel prosthesis 11.
[0137] Preferably the positional indicators are shaped so as to
indicate position and orientation of the branch vessel prosthesis
during and after deployment. The positional markers may be of any
configuration to facilitate their visualization. For example, the
positional markers may be v-shaped with one leg longer than the
other.
[0138] In a preferred embodiment, the positional indicator system
may include a first positional indicator 714 for indicating the
position of the proximal end of the branch vessel prosthesis 11
during deployment, a second positional indicator 716 associated
with the branch vessel prosthesis 11 for indicating the position of
a distal end of the branch vessel prosthesis 11 during deployment,
a third positional indicator 712 associated with the branch vessel
prosthesis 11 for indicating the position of a point along the
branch vessel prosthesis 11 predetermined for optimal alignment
with the fenestration 7 during deployment. The system 711 can also
include a fourth positional indicator 718 on the aorta stent graft
1 indicating the position of the fenestration 7. At least first,
second and third positional indicators also may located on the
branch vessel prosthesis 11, as previously described, and are
shaped so as to indicate position and orientation of the branch
vessel prosthesis 11 during and after deployment.
[0139] In operation, the branch vessel prosthesis 11 is positioned
about the balloon on the catheter and crimped thereto so that
desired portions of the branch vessel prosthesis 11 align with the
corresponding positional indicators of the positional indicator
system 711. The marker system 711 may be placed on a wire guide
lumen 720 or an inflation lumen 722 of the balloon catheter. The
balloon may comprise a see-through material so that the marker
system 711 can be viewed therethrough to facilitate the placement
of the branch vessel prosthesis 11 in the loading area. In one
variation shown in FIGS. 26D-E, the balloon catheter may comprise a
multi-lumen balloon catheter having a support lumen 724 having a
flaring portion through which a mandril (not shown) extends. The
mandril stops proximally of the balloon. The mandril provides
support to the delivery catheter 702. The mandril may comprise a
tapered wire.
[0140] The delivery system may also include a balloon expansion
catheter 800 that is configured to expand a branch vessel
prosthesis of the various configurations described herein having a
flaring portion 802 and a tubular portion 804. As shown in FIG.
27A, a delivery catheter 800 may comprise multiple balloons 806,
808. Preferably, the first balloon 806 may be sized and adapted to
flare the flaring portion 804 of a branch vessel prosthesis 11, as
described herein, and the second balloon 808 may be sized and to
adapted expand a tubular portion of a branch vessel prosthesis, as
described herein. Accordingly, the balloons may have different
compliances.
[0141] As shown in 27A, the balloons 806, 808 may be positioned on
a branch vessel prosthesis loading area 810 such that the when the
branch vessel stent graft 11 is mounted on the stent-loading area
810, the tubular portion 804 of the branch vessel stent graft 11
aligns with the first balloon 806 and the flaring portion 802 of
the branch vessel stent graft 11 that is configured to align with
the fenestration 7 of the aorta stent graft 1 is aligned with the
second balloon 808.
[0142] In one embodiment, the balloon catheter carrying the
balloons 806, 808 is introduced into the lumen of the aorta stent
graft (not shown). The first balloon 806 is aligned substantially
with the flaring portion 802 of the branch vessel stent graft 11
and the second balloon 808 is aligned substantially with the
tubular portion 806 and the balloons are inflated, as shown in FIG.
27B. The balloons 806, 808 may be inflated simultaneously so as to
simultaneously expand the tubular portion and flare the flaring
portion. Alternatively, the balloons 806, 808 may be sequentially
inflated. In one embodiment, the second balloon 808 is inflated
before the first balloon 806, thereby expanding the tubular section
804 before flaring the flaring portion 802. Alternatively, the
first balloon 806 may be inflated first. The catheter may be
adapted such that the balloons may be inflated independently of
each other. The first balloon 806 may be constructed of a
semi-compliant (or non-compliant) material and the second balloon
808 may be constructed of a compliant material.
[0143] In an alternative configuration, shown in FIG. 27C the
delivery catheter 800 may have a single balloon 806 having a first
portion 803 for expanding the tubular portion 804 and a second
portion 805 for expanding the flaring portion 802 of the branch
vessel prosthesis 11. As shown in FIG. 27D, the inflated diameter
D.sub.1 of the first portion 803 may be smaller than the inflated
diameter D.sub.2 of the second portion 805.
[0144] In another variation, shown in FIGS. 27E-F, the balloon 806
includes a first portion 803, a second portion 805, and a third
portion 807, with the first portion 803 for expanding the tubular
portion 804 and a second portion 805 for expanding the flaring
portion 802 of the branch vessel prosthesis 11. The third portion
807 of the balloon 806 is sized and configured to align with that
part of the branch vessel prosthesis 11 that aligns with the
fenestration 7 of the aorta stent graft 1. As shown in 27E, the
first portion 803 and the second portion 805 may have substantially
the same diameter D.sub.1. The third portion 807 may have a
diameter D.sub.2 smaller than the diameter D, of the first and
second portions 803, 805. Alternatively, as shown in FIG. 28F, the
diameter D.sub.1 of the first portion 803 may be smaller than the
diameter D.sub.2 of the second portion 805 and greater than the
diameter D.sub.3 of the third portion 807.
[0145] The balloon 806 may also have multiple layers that extend
over the balloon length as shown in FIG. 27G-H. For example, the
multi-layer balloon 806 may include an inner layer 810 and an outer
layer 812. The inner and outer layers 810, 812 may be of different
compliancy. The inner layer 810 may be less compliant than the
outer layer 812. For example, the inner layer 810 may be
constructed of a semi-compliant or noncompliant material, and the
outer layer 812 may be constructed of a compliant material. To
expand and flare the branch vessel prosthesis 11 with this
embodiment, the inner layer may be inflated to expand the branch
vessel prosthesis 11. Subsequently or simultaneously, the outer
layer 812 may be inflated to expand or flare the flaring portion
814, which is not constrained by the branch vessel 5, of the branch
vessel stent graft 814.
[0146] In each of the embodiments described, the balloon catheter
may be the same as the branch vessel prosthesis introducer or it
may be a separate device. In addition, the balloon catheter may
comprise a monorail system or rapid-exchange type system. The
balloons described may be inflated in any manner known to one of
skill in the art. For example, the delivery catheter may include a
lumen having a port that exits into the balloon for delivering an
inflation fluid to the balloon. When two balloons are present, the
delivery catheter may include a first fluid delivery lumen and port
for inflation of one balloon and a second fluid delivery lumen and
port for inflation of the other balloon. Alternatively, a single
lumen may be used that has two ports and a valve for alternating
delivery of fluid to the two ports.
[0147] Deployment
[0148] The branch vessel prosthesis can be deployed in any method
known in the art, preferably, the method described in WO 98/53761
in which the device is inserted by an introducer via a surgical
cut-down into a an artery, and then advanced into the desired
position over a stiff wire guide using endoluminal interventional
techniques. For example, a guide wire (not shown) is first
introduced into an artery of the patient and advanced until its tip
is beyond the desired deployment region the aortic stent graft 1.
At this stage, the introducer assembly 500 is fully assembled, and
ready for introduction into the patient.
[0149] Referring to the components of FIG. 23 and FIGS. 5A-C, the
branch vessel prosthesis 11 is retained at one end by the
cylindrical sleeve 520 and the other by a proximal attachment
section 536, and compressed by the sheath 532. Because the branch
vessel prosthesis 11 is mounted on the delivery system in the
opposite direction (i.e., the distal end is retained in the
cylindrical sleeve and the proximal end is retained in what was
previously referred to as the distal attachment section 536),
various of the components referred to previously with regard to the
introduction system for the aorta stent graft 1 are referred to
here as distal rather than proximal and proximal rather than
distal.
[0150] If the branch vessel prosthesis is to be placed in a branch
vessel of the abdominal or thoracic aortic arteries, the introducer
assembly 500 can be inserted through a femoral artery over the
guide wire, and positioned by radiographic techniques, which are
not discussed here.
[0151] Once the introducer assembly 500 is in the desired
deployment position, the sheath 532 is withdrawn to just proximal
of the distal attachment section 536. This action releases the
middle portion of the branch vessel prosthesis 11 so that it can
expand radially. The distal end of the 32 of the branch vessel
prosthesis, for example as shown in FIG. 4A, however, is still
retained within the cylindrical sleeve 520 (the end cap as shown in
FIG. 25B). Also, the proximal end 30 of the branch vessel
prosthesis 11 is still retained within the external sheath 532.
[0152] Next, the pin vise 550 is released to allow small movements
of the thin walled tube 524 with respect to the thick walled tube
530. These movements allow the prosthesis 11 to be lengthened or
shortened or rotated or compressed for accurate placement in the
desired location within the lumen. Positional indicators, such as
X-ray opaque or radio markers (not shown) may be placed along the
branch vessel prosthesis 11 to assist with placement of the
prosthesis.
[0153] When the distal end of the branch vessel prosthesis 11 is in
place in branch vessel, the distal trigger wire is withdrawn by
movement of the distal wire release mechanism 540. The distal wire
release mechanism 540 and the distal trigger wire can be completely
removed by passing the distal wire release mechanism 540 over the
pin vise 550, the screw cap 550, and the connection means 526.
[0154] Next, the screw cap 550 of the pin vise 540 is then
loosened. After this loosening, the thin walled tube 524 can be
pushed in a distal direction to move the cylindrical sleeve 530 in
a distal direction. When the 520 no longer surrounds a barbed
self-expanding stent (such as 40 in Figure A), the self-expanding
stent expands. When the self-expanding stent expands, the barbs 42
grip the walls of the lumen to hold the proximal end of the
prosthesis 11 in place. From this stage on, the proximal end of the
prosthesis 11 typically cannot be moved.
[0155] Once the tubular portion 33 has been placed in the branch
vessel and the distal end of the branch vessel prosthesis 11 is
anchored, the external sheath 432 is withdrawn to proximal of the
proximal attachment section 536. This withdrawal releases the
flaring portion 36 of the branch vessel prosthesis 11 within the
aorta stent graft lumen. Upon release the flaring portion 36, if it
is constructed of self expanding material, flares and secures the
flaring portion within the lumen of the aorta-stent graft 11.
Thereafter, either or both the flaring portion 36 and the tubular
portion 33 may be expanded or further expanded by one or more
balloons. Alternatively, the prosthesis may be delivered by way of
one of the balloon catheters described previously herein.
[0156] Throughout this specification various indications have been
given as to the scope of the invention but the invention is not
limited to any one of these but may reside at two or more of these
combined together. It is therefore intended that the foregoing
detailed description be regarded as illustrative rather than
limiting, and that it be understood that it is the following
claims, including all equivalents, that are intended to define the
spirit and scope of this invention.
* * * * *