U.S. patent application number 12/230895 was filed with the patent office on 2009-01-08 for system and method for endoluminal grafting of bifurcated and branched vessels.
This patent application is currently assigned to CardiAQ Valve Technologies, Inc.. Invention is credited to Arshad Quadri.
Application Number | 20090012602 12/230895 |
Document ID | / |
Family ID | 34465117 |
Filed Date | 2009-01-08 |
United States Patent
Application |
20090012602 |
Kind Code |
A1 |
Quadri; Arshad |
January 8, 2009 |
System and method for endoluminal grafting of bifurcated and
branched vessels
Abstract
A system and method for endoluminal grafting of a main anatomic
conduit in its diseased state in which it dilates to pose a life
threatening condition and its various conduits that emanate from
the main anatomic conduit. The grafting system comprises an
endoaortic graft having at least one opening therein and at least
one branch graft that is passable through the opening of the
endoaortic graft into the branch anatomic conduit(s) such that the
junction between the branch graft and the endoaortic graft is
substantially fluid tight. A system and method for delivery of the
endoaortic graft and also a system and method for efficient
alignment and deployment of the branch (e.g., side branch) graft
such that the coupling of the branch graft with the endoaortic
graft is efficient and exact and fluid-tight; and a system and
method for coupling the branch to the endoaortic graft via a
coupling mechanism employing a memory metal alloy; a system and
method for the proper and exact alignment of the endoaortic graft
and the branch using magnetic force of a suitable nature, and which
does not use the magnetic force as the coupling mechanism.
Inventors: |
Quadri; Arshad; (West
Hartford, CT) |
Correspondence
Address: |
JACOBSON HOLMAN PLLC
400 SEVENTH STREET N.W., SUITE 600
WASHINGTON
DC
20004
US
|
Assignee: |
CardiAQ Valve Technologies,
Inc.
Winchester
MA
|
Family ID: |
34465117 |
Appl. No.: |
12/230895 |
Filed: |
September 8, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10960296 |
Oct 8, 2004 |
7425219 |
|
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12230895 |
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60509904 |
Oct 10, 2003 |
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Current U.S.
Class: |
623/1.35 ;
606/153; 623/1.13 |
Current CPC
Class: |
A61F 2/064 20130101;
A61F 2210/009 20130101; A61F 2/954 20130101; A61F 2230/005
20130101; A61F 2/90 20130101; A61F 2250/0001 20130101; A61F
2220/0066 20130101; A61F 2220/0075 20130101; A61F 2220/005
20130101; A61F 2002/061 20130101; A61F 2002/9511 20130101; A61F
2250/0069 20130101; A61F 2/07 20130101; A61F 2002/075 20130101 |
Class at
Publication: |
623/1.35 ;
606/153; 623/1.13 |
International
Class: |
A61F 2/06 20060101
A61F002/06; A61B 17/08 20060101 A61B017/08 |
Claims
1. A system for endoluminal grafting of a native, main anatomic
conduit, in a region where at least one branch anatomic conduit
extends from the main anatomic conduit, comprising: an endoaortic
graft including a first pliable tube having a lumen extending
longitudinally therefrom, at least one branch opening formed in the
first pliable tube, and endoaortic graft anchoring means for
holding the first pliable tube in substantially fixed place within
the main anatomic conduit with the branch opening in alignment with
the branch anatomic conduit, the first pliable tube being made of a
biocompatible material; a branch graft including a second pliable
tube having a proximal end, a mid-portion, a distal end, a lumen
extending therethrough, and branch graft anchoring means at the
distal end for holding at least the distal end of the branch graft
in contact with the surrounding wall of the branch anatomic
conduit, the second pliable tube being made of a biocompatible
material, the second pliable tube being sized to be receivable
through the branch opening such that a junction between the
endoaortric branch and the branch graft is substantially fluid
tight; selectively activatable connector means for connecting the
proximal end of the second pliable tube with the branch opening of
the first pliable tube upon activation to allow the fluid that
flows through the lumen of the endoaortic graft to pass through the
branch opening into the lumen of the branch graft, wherein the
connector means includes a portion made from memory metal for
effecting a mechanical, non-magnetic connection between the
proximal end of the second pliable tube and the branch opening of
the first pliable tube; endoaortic graft delivery means for
introducing the first pliable tube into the anatomic conduit; and
branch graft delivery means for housing the second pliable tube and
introducing it into the branch anatomic conduit.
2. The system of claim 1, wherein the endoaortic graft delivery
means includes: an outer sheath; an inner central sheath
substantially concentric with the outer sheath for carrying an
axial guide wire; at least one inner side sheath radially
positioned between the inner central sheath and a corresponding
branch opening for carrying the separate branch anatomic conduit
guide wire, the first pliable tube being loaded in the endoaortic
graft delivery means such that the branch anatomic conduit guide
wire carried by the at least one inner side sheath to the branch
anatomic conduit traverses through the corresponding at least one
branch opening; and a tapered and flexible tip at the distal end of
the inner central sheath, the tip forming the nose cone of the
endoaortic graft delivery means and having apertures, one of which
allows the passage of the axial guide wire therethrough.
3. The system of claim 2, further comprising at least one separate
branch anatomic conduit guide wire that is to be passed into a
corresponding side branch anatomic conduit, the at least one branch
anatomic conduit guide wire being positioned in a corresponding
inner side sheath for passage through one of the apertures in the
tip of the branch graft delivery means.
4. The system of claim 1, wherein the mid-portion of the second
pliable tube includes means for maintaining a patent lumen therein
such that the branch graft is kink resistant in an angular
situation.
5. The system of claim 1, wherein the endoaortic graft anchoring
means comprises at least one of a radially expandable stent, a
frame, hooks, rings, sutures, staples, adhesive, and staples.
6. The system of claim 1, wherein the connector means includes a
material having sufficient magnetic properties to be attracted to
the flexible magnetic ring yet still be easily movable relative
thereto.
7. The system of claim 1, wherein the endoaortic graft further
includes a flexible magnetic ring positioned around the at least
one branch opening of the first pliable tube, and wherein the
branch graft delivery means includes: a hollow outer sheath, the
outer sheath being non-retractable and carrying a magnet at its
distal end; a hollow inner sheath concentric with the outer sheath,
and a hollow middle sheath concentric with and positioned between
the outer and inner sheaths, the branch graft being housed between
the inner sheath and the middle sheath, at least a portion of the
middle sheath covering the branch graft; a tapered and flexible tip
at the distal end of the inner central sheath, the tip forming the
nose cone of the branch graft delivery means; whereby when the
middle sheath is retracted, it will uncover the branch graft such
that the branch graft is deployed fully to form a connection with
the endoaortic graft.
8. The system of claim 7, wherein the magnetic ring is selected
from the group consisting of an electromagnet, a ferromagnet, and a
ferromagnetic fluid.
9. The system of claim 7, wherein the flexible magnetic ring is
positioned on the exterior surface of the first pliable tube.
10. The system of claim 9, wherein the flexible magnetic ring is
permanently secured to the exterior surface of the first pliable
tube.
11. The system of claim 7, wherein the flexible magnetic ring is
positioned on the interior surface of the first pliable tube.
12. The system of claim 11, wherein the flexible magnetic ring is
removably secured to the interior surface of the first pliable
tube.
13. The system of claim 7, wherein the magnet of the branch graft
delivery means has a natural magnetic field.
14. The system of claim 7, wherein the magnet of the branch graft
delivery means has an induced magnetic field.
15. The system of claim 7, wherein the magnet of the branch graft
delivery means is chosen from the group consisting of an
electromagnet, a ferromagnet, and a ferromagnetic fluid.
16. The system of claim 7, wherein the outer sheath is rotatable so
as to change the polarity of the magnet in a particular plane.
17. The system of claim 7, wherein prior to deployment, the distal
ends of the inner and middle sheaths are substantially coterminous,
and the middle sheath covers substantially the entire length of the
branch graft.
18. The system of claim 7, wherein prior to deployment, the distal
end of the inner sheath extends outwardly of the distal ends of the
middle and outer sheaths, with the branch graft loaded over the
distal end of the middle sheath with only the connector means
housed between the middle and outer sheaths, and wherein the branch
graft delivery system includes means for maintaining the branch
graft in a contracted condition prior to deployment.
19. The system of claim 18, wherein the means for maintaining the
branch graft in a contracted position includes a deployment wire
radially positioned between the inner and middle sheaths, and a
thread wrapped around both the contracted branch graft and the
deployment wire in a figure-8 configuration, whereby when the
deployment wire is retracted, the wrapping unravels, allowing the
branch graft to assume an expanded condition.
20. The system of claim 19, wherein the thread is made of a
biodegradable, absorbable material.
21. A method for endoluminal grafting of a native, main anatomic
conduit and a branch anatomic conduit extending from the main
anatomic conduit, in a region where at least one branch anatomic
conduits extends from the main anatomic conduit, using an
endoaortic graft including a first pliable tube having a lumen
extending longitudinally therefrom, at least one branch opening
formed in the first pliable tube, a flexible magnetic ring
positioned around the at least one branch opening of the first
pliable tube, and endoaortic graft anchoring means for holding the
first pliable tube in substantially fixed place within the main
anatomic conduit with the branch opening in alignment with the
branch anatomic conduit, the first pliable tube being made of a
biocompatible material; and a branch graft including a second
pliable tube having a proximal end, a mid-portion, a distal end, a
lumen extending therethrough, connector means for connecting the
proximal end with the branch opening of the first pliable tube to
allow the fluid that flows through the lumen of the endoaortic
graft to pass through the branch opening into the lumen of the
branch graft, and anchoring means at the distal end for holding at
least the distal end of the branch graft in contact with the
surrounding wall of the branch anatomic conduit, the second pliable
tube being made of a biocompatible material, the method comprising
the steps of: advancing an axial guide wire into the body of an
aneurysm, and then advancing a second, more pliable balloon tipped
guide wire into the branch anatomic conduit; transluminally
advancing the endoaortic graft over the guide wires into the branch
anatomic conduit; positioning the endoaortic graft within the main
anatomic conduit such that the branch opening is aligned with the
branch anatomic conduit; utilizing the endoaortic graft anchoring
means to anchor the endoaortic graft within the main anatomic
conduit; transluminally advancing the branch graft loaded in a
retractable sheath of a branch graft delivery system over the guide
wire to the branch anatomic conduit, the branch graft delivery
system including a magnetic ring at its distal end; passing the
distal end of the branch graft delivery system containing the
branch graft through the branch opening and into the branch
anatomic conduit, until the magnetic ring of the endoaortic graft
and the magnetic ring on the branch delivery system attach;
operating the branch graft delivery system such that the branch
graft is deployed in the branch anatomic conduit, until such time
that the retractable sheath of the delivery system is fully
retracted; and once the retractable sheath of the branch graft
delivery system is fully retracted, rotating the outer sheath of
the branch graft delivery system by 180 degrees to switch the
magnetic poles to allow the two magnetic rings to disengage.
22. The method of claim 21, wherein in said step of rotating the
outer sheath, the most proximal part of the connector means is
deployed, allowing the leak proof connection between the branch
graft and the endoaortic graft.
23. The method of claim 21, further comprising the steps of:
withdrawing the branch graft delivery system after said step of
rotating the outer sheath; advancing another guidewire through the
lumen of the endoaortic graft; activating the connector means of
the endoaortic graft to engage the proximal end of the branch
graft.
24. The method of claim 21, further comprising the step of removing
the flexible magnetic ring of the endoaortic graft.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present patent application is a divisional of U.S.
application Ser. No. 10/960,296, filed Oct. 8, 2004, which is based
on, and claims priority from, U.S. provisional Application No.
60/509,904, filed Oct. 10, 2003, both of are is incorporated herein
by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to medical devices
and methods, and more particularly to a system and method for
endoluminal grafting of blood vessels or other tubular, main
anatomic conduits which have furcations or side branches extending
there from.
[0004] 2. Related Art
[0005] Endoluminal grafting is a relatively noninvasive method for
placing a tubular graft within the lumen of a native, main anatomic
conduit, such as a blood vessel. In certain cardiovascular
applications of conventional or prior art techniques for
endoluminal grafting, an endovascular graft may be implanted in the
aneurismal segment of a blood vessel to form a prosthetic blood
flow conduit through the aneurysm, and to effectively isolate the
weakened portion of the blood vessel wall from hemodynamic forces
and pressures of the flowing blood.
[0006] The prior art has included numerous endovascular grafts of
varying design. In general, these endovascular grafts typically
comprise a tube made of a pliable material such as PTFE, polyester,
woven Dacron.RTM., etc., in combination with a graft anchoring
component (e.g., a stent, a frame, hooks, a series of wire rings,
clips, staple, etc.) that operates to hold the grafts in its
intended position within the blood vessel.
[0007] An example of a commonly used endovascular primary stent
graft is the AneuRx stent graft sold by Medtronic. A sleeve may be
used at the end of the graft if the graft itself is not
sufficiently long. With or without the sleeve, a conventional
endovascular stent graft requires the neck (the area of the vessel
between the branches and the aneurysm) to be of sufficient size to
permit attachment of the graft. A conventional endovascular stent
graft cannot be used if the neck is too short (this problem is
described in some detail in U.S. Pat. No. 6,428,565 to Wisselink,
in the paragraph bridging columns 2 and 3).
[0008] Endovascular grafting is a clinically-acceptable alternative
to traditional surgery in patients who suffer from aneurysms of the
aorta. Indeed, many patients who are diagnosed with aortic
aneurysms are relatively high-risk patients and may be classed as
poor-risk for traditional surgery. If allowed to remain untreated,
the aneurysm will surely dissect or rupture, causing a catastrophic
event leading to significant risk of death to the patient. The
traditional surgery in itself incurs significant risk of morbidity
and mortality to the patient, due to its inherently extensive
nature, which includes excessive blood loss, intra-operative heart
attacks, and organ system ischaemias due to the cross-clamping of
the aorta, which is an inherent part of the procedure. Thus,
endovascular grafting offers a potential means of repair of aortic
aneurysm without the risks and potential complication of
traditional surgery. At the present time, endoluminal grafting can
be performed in patients with aneurysms isolated to the infra-renal
position or at the juxta-renal position with great benefit to the
high-risk patients, but is not extendable to a large population of
patients that suffer with aneurismal disease of the aorta that
involves its major branches.
[0009] Depending on which region of the aorta is/are involved, the
aneurysm may extend into areas of bifurcation (i.e., the inferior
end of the aorta where it bifurcates into the iliac arteries) or
segments of the aorta from which smaller branches extend. In this
regard, aortic aneurysms can be classified into three basic types
and five sub-types on the basis of the regions of the aneurismal
involvement, as follows:
[0010] A. Thoracic Aortic Aneurysms: [0011] 1. Aneurysms involving
the ascending aorta [0012] 2. Aneurysms involving the aortic arch
and branches that emanate therefrom (i.e., subclavian artery,
common carotid artery, innominate artery)
[0013] B. Thoracoabdominal Aortic Aneurysms: Aneurysms involving
the descending thoracic aorta and arteries that emanate from it
(i.e., thoracic intercostals arteries) and/or the supra-renal
abdominal aorta and branch arteries that emanate therefrom (i.e.,
renal, superior mesenteric, celiac, and/or the intercostals
arteries).
[0014] C. Abdominal Aortic Aneurysm: [0015] 1. Aneurysms involving
the para-renal aorta and the branches that emanate therefrom (i.e.,
the renal arteries). [0016] 2. Aneurysms involving the infrarenal
aorta with or without iliac involvement.
[0017] Unfortunately, not all the patients diagnosed with aortic
aneurysm are presently considered to be candidates for endovascular
grafting. This is largely due to the fact that most of the
endovascular grafting systems are not designed for use in regions
of the aorta from which side branches (i.e., carotids, innominate,
subclavian, intercostals, superior mesenteric, celiac, renal)
extend. In fact, most endovascular grafting systems have been in
the treatment of infra-renal aneurysms, with or without the
involvement of the iliac arteries. There are numerous examples in
the prior art of endovascular grafting method and systems useable
to treat such infra-renal aneurysms, with or without iliac artery
involvement.
[0018] Patent Application Publication No. 2002/0103495 and U.S.
Pat. No. 6,352,543 (Cole) disclose methods and devices for forming
an anastomosis between hollow bodies using magnetic force to couple
anastomotic securing components 78, 80 and create a fluid-tight
connection between the lumens of the hollow bodies. End-to-side,
side-to-side, and end-to-end anastomoses can be created without
using suture or any other type of mechanical fasteners, although
any such attachment means may be used in conjunction with the
magnetic attachment The securing components have magnetic,
ferromagnetic, or electromagnetic properties and may include one or
more materials, for example, magnetic and nonmagnetic materials
arranged in a laminated structure. As shown in FIG. 9A, the
securing component 78 includes two members, 78A, 78B disposed on
opposite surfaces of a wall of one of the hollow bodies. FIGS.
19A-19C show an embodiment in which one of the securing components
has a flange-type construction. The system of anastomotic securing
components may be used in many different applications including the
treatment of cardiovascular disease, peripheral vascular disease,
forming AV shunts for dialysis patients, etc., and may be sized and
configured for forming an anastomosis to a specific hollow body,
for example, a coronary artery or the aorta.
[0019] Patent Application Publication No. 2002/0143347 (Cole et
al.) discloses methods and devices using magnetic force to form an
anastomosis between hollow bodies. End-to-side, side-to-side, and
end-to-end anastomoses can be created without using sutures or any
other type of mechanical fasteners, although such attachment means
may be used in practicing some aspects of the invention. Magnetic
anastomotic components may be attached to the exterior of a vessel,
e.g., by adhesive, without extending into the vessel lumen. Various
magnetic component configurations are provided and may have
different characteristics, for example, the ability to match the
vessel curvature or to frictionally engage the vessel. FIG. 5B
shows sutures S used to attach the component 16 to a vessel V,
although it is stated that any suitable mechanical fastener may be
used, e.g., clips, stents, barbs, hooks, wires, etc. FIG. 8B shows
a magnetic anastomotic component 50 having an opening 52 and
attachment structure 54 to facilitate securing the component to a
vessel (not shown). As above, the structure 54 may be used alone or
in combination with other means for securing the component to the
vessel. In the illustrated embodiment, the attachment structure 54
is affixed to the component 50 to define a plurality of openings 56
which may be use to receive sutures, clips, clamps, pins, barbs, or
other securing or fastening means.
[0020] Patent Application Publication No. 2001/0041902 (Lepulu et
al.) discloses anastomotic methods and devices for placing a target
vessel in fluid communication with a source of blood. FIGS. 11 and
12 show an embodiment utilizing magnets to secure the target vessel
wall. In FIG. 11, a first securing component 90, preferably having
a rectangular shape with rounded ends, is formed of magnetic
material (or provided with magnetic material), as is a second
securing component 92. The poles of the magnets are arranged to
attract the components 90, 92 to one another and capture the tissue
of the target vessel wall. FIG. 12 shows another embodiment wherein
a first securing component 94 is carried by a conduit body 96,
which is provided with a magnetic collar 98. A second securing
component 100 has a magnetic collar 102, the poles of these magnets
being arranged to repel the collars and force the components 94,
100 together.
[0021] U.S. Pat. Nos. 5,989,276 and 6,293,955 and Patent
Application Publications Nos. 2003/0014061, 2003/0014062,
2003/0014063, 2001/0051809, and 2002/0052637 (Houser et al.)
disclose a bypass graft incorporating fixation mechanisms at its
opposite ends, for securing these ends to different locations along
a blood vessel, or alternatively to different locations wherein one
of the locations is a different vessel or an organ defining a
cavity. Mechanical fixation features such as collets or grommets
can be employed, enhanced by delivery of an electrical current
sufficient to heat surrounding tissue to form a thermal bond. A
graft deployment system includes a tissue dilator and a needle for
perforating tissue, mounted coaxially within the dilator.
Intraluminal systems further include a catheter for containing the
dilator. To further assist positioning, magnets may be incorporated
into the dilator near its distal tip, as indicated at 206 for a
dilator 208 shown in FIG. 25. Such magnets may be formed of ferrite
materials, or alternatively may be formed by winding conductive
coils around the dilator to form electromagnets when current is
supplied. The dilator magnets are used in conjunction with a guide
wire 209 advanced beyond a stenosed lesion 210 within a vessel 212.
The guide wire is formed of metal, and to further enhance magnetic
attraction may incorporate a magnet 214 of opposite polarity to the
dilator magnet. Magnetic positioning is stated to facilitate
placing bypass grafts through tortuous vessels or over long
distances beyond the lesion.
[0022] Houser et al. also disclose tissue dilators of deployment
systems for graft fixation. Magnets may be incorporated into the
dilator near its distal tip, as indicated at 206 for a dilator 208
shown in FIG. 25. Such magnets may be formed of ferrite materials,
or alternatively may be formed by winding conductive coils around
the dilator to form electromagnets when current is supplied. The
dilator magnets are used in conjunction with a guide wire 209
advanced beyond a stenosed lesion 210 within a vessel 212. The
guide wire is formed of metal, and to further enhance magnetic
attraction may incorporate a magnet 214 of opposite polarity to the
dilator magnet. Magnetic positioning is stated to facilitate
placing bypass grafts through tortuous vessels or over long
distances beyond the lesion.
[0023] U.S. Pat. Nos. 6,074,416 and 6,451,048 and Patent
Application Publication No. 2002/0151913 (Berg et al.) disclose
connector structures 34 for attaching elongated flexible tubular
grafts to the body organ tubing of a patient. The connector
structures are formed from nitinol wire.
[0024] U.S. Pat. No. 6,068,654 (Berg et al.) discloses a two-piece
graft connector having a tubular band section with its proximal end
configured to attach to a tubular graft and retention loops
extending from its distal end, and a tubular anchor structure
configured to be placed in the patient's tubular body tissue
structure. The retention loops 26 can be made of nitinol wire. In
one embodiment (see FIG. 1), the proximal end of the tubular band
section is attached to a tubular graft. The retention loops extend
from the distal end of the tubular band section of the connector,
through an aperture in the side wall of a patient's tubular body
tissue structure, and the tubular anchor structure is placed in the
patient's tubular body tissue structure, within the retention
loops. In another embodiment (see FIG. 9), retention loops 26 are
replaced by relatively thicker retention fingers 70, which do not
form loops, but instead form arcs, extending partially around the
circumference of tubular body structure 11.
[0025] Methods for graft placement are disclosed in Patent
Application Publications Nos. 2002/0143383 (Parodi) and
2002/0072790 (McGuckin, Jr. et al.) and U.S. Pat. No. 6,428,565
(Wisselink). Wisselink also describes the problems associated with
using a conventional endovascular stent graft when the neck is too
short (see the paragraph bridging columns 2 and 3).
[0026] With reference to FIGS. 15a-21, U.S. Pat. No. 6,068,637
(Popov et al.) discloses a method and devices for performing
end-to-side anastomoses between the severed end of a first hollow
organ and the side-wall of a second hollow organ utilizing a
modified cutter catheter which is introduced into the first hollow
organ in combination with a receiver catheter which is introduced
into the second hollow organ. The distal end of the receiver
catheter includes a receiver cavity and a selectively activatable
magnetic material. The magnetic material is selected so that it
will interact with a magnetically susceptible material disposed in
the distal end of the modified cutter catheter when the modified
cutter catheter is disposed in proximity to the proposed site for
anastomosis whereby the severed end of the first hollow organ is
matingly engaged with the sidewall of the second hollow organ.
Thereafter, the severed end of the first hollow organ can be
attached in sealing engagement with the side-wall utilizing clips,
a biocompatible glue, or other suitable methods. The cutter is then
activated to remove a portion of the side-wall of the second hollow
organ, thereby creating an opening within the region of securement
and establishing the anastomosis. In the preferred embodiment, the
portion of the sidewall of the second hollow organ is engaged in
the receiver cavity by the attractive force between the
magnetically susceptible material and the magnetic material. The
magnetically susceptible material is then released from the
modified cutter catheter and withdrawn along with the portion of
the sidewall removed by the cutter when the receiver catheter is
withdrawn from the second hollow organ.
[0027] Most, if not all, of the endovascular grafts that have been
designed for use in treating infra-renal aneurysms require that a
proximal neck of adequate length exists inferior to the renal
arteries, in order to provide a region where the superior end of
the graft may be securely anchored so that blood flow to the renal
arteries is not restricted. The deployment of an endovascular graft
within the regions of the aorta from which the branch anatomic
conduits emanate presents an additional technical challenge,
because in those cases, the endovascular graft must be designed
such that it can be inserted, aligned, and deployed with discrete
maintenance of blood flow to the side branch anatomic conduits by
means of additional branch grafts that arise from the
newly-constructed endoaortic graft. This should be done in a manner
that maintains sufficient blood flow to the branch anatomic conduit
and yet exclude the aneurismal segment of the aorta from the
haemodynamic consequences.
[0028] U.S. Pat. No. 5,425,765 (Tifenbrun et al.) discloses an
endovascular graft that has one or more openings or fenestrations
formed at specific locations, to allow blood to flow from the aorta
into one or more of the branch arteries. However, such
fenestrations do not form discrete connections with the branch
arteries through which blood flows into the branch anatomic
conduits. As a result, the area surrounding the fenestrations is
prone to leakage of blood around the fenestrations, which might
lead to migration of the graft as well as exposing that segment of
aorta to the systemic blood pressure and other systemic hemodynamic
effects. This defeats the entire concept of treatment of aneurismal
disease, as the aortic wall is not entirely excluded after
placement of the endoluminal graft. The migration of the
endoluminal graft that might occur due to leakage around the
fenestration might also compromise the blood flow to the branch
anatomic conduit.
[0029] U.S. Pat. No. 6,428,565 (Wisselink et al.) discloses an
endovascular graft that forms connections with the branch anatomic
conduit with separate conduits. However, the technique and methods
disclosed by Wisselink et al. have inherent deficiencies in more
than one area. Wisselink et al. use conventional x-ray imaging
techniques to introduce the grafts into the human body, but do not
describe the delivery system and the technique of delivery such
that it would make the procedure safer and most efficient. The use
of conventional radiological methods to position a stent, graft, or
prostheses is routine, but in this instance, the landing zone is
very limited. Thus, in conjunction with fluoroscopy, an additional
technique is required to align the endoaortic graft with the branch
anatomic conduit and position the branch graft in such a manner
that once completed, a conduit is created that supplies the branch
anatomic conduit with unhampered blood flow. Wisselink et al.'s
method for coupling of the branch graft to the aortic graft is
prone to dislodgement thus prone to leakage of blood around the
prosthesis. This will also promote graft migration. Post-implant
migration and leakage may lead to obstruction of blood flow to the
branch anatomic conduits.
[0030] U.S. Pat. No. 6,352,543 (Cole et al.) discloses a method of
forming anastomosis between two hollow bodies, and the use of
magnetic force as a coupling force to form a fluid tight junction.
Cole et al.'s method in all its embodiments uses magnetic material
as an anastomotic securing force and thus forms the actual fluid
tight connections. However, this technique causes a rigid
connection between two hollow organs that may lead to potential
problems due to their fixed nature, and in the event of anastomotic
narrowing are not amenable to interventional techniques in
correcting the problems. Cole et al.'s method uses magnetic force
as a method of attachment and refers to it as the means of
anastomosis.
[0031] Thus, in view of the above-discussed limitations and
shortcomings, there remains a need in the art for development of
new endovascular grafting systems and methods which (a) may be
useable for endovascular grafting in regions of the aorta where
branch anatomic conduits (e.g., subclavian, innominate, carotid,
intercostals, celiac, mesenteric, renals and iliac arteries)
extend, and/or (b) may enable more aortic aneurysms patients to be
candidates for endovascular repair, and/or (c) may advance the
state of the art of endovascular grafting to improve patient
outcomes or lessen complications.
[0032] It is to the solution of these and other problems that the
present invention is directed.
SUMMARY OF THE INVENTION
[0033] It is accordingly a primary object of the present invention
to extend the benefit of endoluminal grafting to a large population
of patients that suffer with aneurismal disease of the aorta that
involves its major branches.
[0034] It is another object of the present invention to provide a
system and method for endoluminal grafting of a blood vessel or
other anatomic conduit, in a region where one or more branch
anatomic conduits (e.g., side branches, furcating, etc.) extend
from the main anatomic conduit.
[0035] It is still another object of the present invention to
provide endovascular grafting systems and methods which (a) may be
useable for endovascular grafting in regions of the aorta where
branch anatomic conduits (e.g., subclavian, innominate, carotid,
intercostals, celiac, mesenteric, renals and iliac arteries)
extend, and/or (b) may enable more aortic aneurysms patients to be
candidates for endovascular repair, and/or (c) may advance the
state of the art of endovascular grafting to improve patient
outcomes or lessen complications.
[0036] These and other objects of the invention are provided by a
system and method for endoluminal grafting of a main anatomic
conduit in its diseased state in which it dilates to pose a life
threatening condition (e.g., aortic aneurysms) and its various
conduits (e.g., side branch anatomic conduits such as the left
common carotid, subclavian, innominate, intercostals, superior
mesenteric, celiac, or renal arteries or bifurcation such as the
iliac arteries) that emanate from the main anatomic conduit.
[0037] The grafting system comprises 1) an endoaortic graft
(endoaortic cuff) having at least one opening therein and 2) at
least one branch graft that is passable through the opening of the
endoaortic graft into the branch anatomic conduit(s) such that the
junction between the branch graft and the endoaortic graft is
substantially fluid tight.
[0038] In one aspect, the invention comprises a system and method
for delivery of the endoaortic graft and also a system and method
for efficient alignment and deployment of the branch (e.g., side
branch) graft such that the coupling of the branch graft with the
endoaortic graft is efficient and exact and fluid-tight.
[0039] In another aspect, the invention comprises a system and
method for coupling the branch conduit to the endoaortic graft via
a coupling mechanism employing a memory metal alloy. Two different
embodiments of coupling mechanisms are provided, the coupling
mechanism being chosen depending on the site and anatomic location
of the branch conduit. In one embodiment, the coupling mechanism is
incorporated in the endoaortic graft and in the other embodiment,
the coupling mechanism is incorporated in the endobranch graft.
[0040] In still another aspect, the invention comprises a system
and method for the proper and exact alignment of the endoaortic
graft and the branch conduit using magnetic force of a suitable
nature, and which does not use the magnetic force as the coupling
mechanism.
[0041] Other objects, features and advantages of the present
invention will be apparent to those skilled in the art upon a
reading of this specification including the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] The invention is better understood by reading the following
Detailed Description of the Preferred Embodiments with reference to
the accompanying drawing figures, in which like reference numerals
refer to like elements throughout, and in which:
[0043] FIG. 1A is a perspective view of a first embodiment of an
endoaortic graft in accordance with the present invention.
[0044] FIG. 1B is a cross-sectional view of the endoaortic graft of
FIG. 1.
[0045] FIG. 2A is a cross-sectional view of a delivery system for
introducing the endoaortic graft of FIGS. 1A-1B into a native, main
anatomic conduit in accordance with first and second embodiments of
the present invention.
[0046] FIG. 2B is a cross-sectional view taken along line 2B of
FIG. 2A.
[0047] FIG. 2C is a cross-sectional view taken along line 2C of
FIG. 2A.
[0048] FIG. 3A is a side elevational view of a branch graft in
accordance with a first embodiment of the present invention.
[0049] FIG. 3B is an enlarged perspective view of the connector
mechanism of the branch graft of FIG. 3A, for coupling the branch
graft with the endoaortic graft of FIG. 1A, in the deployed
position.
[0050] FIG. 4A is a cross-sectional view of a delivery system for
introducing the branch graft into a branch anatomic conduit of a
main anatomic conduit in accordance with a first embodiment of the
present invention.
[0051] FIG. 4B is a cross-sectional view of the delivery system of
FIG. 4A, in which the branch graft has been deployed.
[0052] FIG. 5A is a partial perspective view of the outside of an
endoaortic graft in accordance with a second embodiment of the
present invention.
[0053] FIG. 5B is a partial perspective view of the inside of the
endoaortic graft of FIG. 5A with the coupling mechanism for
coupling with the branch graft in the open position, the struts and
the magnetic ring being omitted for clarity.
[0054] FIG. 5C is a partial perspective view of the inside of the
endoaortic graft of FIG. 5A with the coupling mechanism for
coupling with the branch graft in the closed position, the struts
and the magnetic ring being omitted for clarity.
[0055] FIG. 5D is an enlarged view of the coupling mechanism for
coupling with the branch graft of FIGS. 5B and 5C, in the closed
position, the struts being omitted for clarity.
[0056] FIG. 6A is a view of the coupling mechanism of FIGS. 5B and
5C, in the open position, and its accompanying struts, the flexible
magnetic ring being omitted for clarity.
[0057] FIG. 6B is a view of the coupling mechanism of FIGS. 5B and
5C, in the closed position, and its accompanying struts, the
flexible magnetic ring being omitted for clarity.
[0058] FIG. 7A is a side elevational view of a branch graft in
accordance with a second embodiment of the present invention.
[0059] FIG. 7B is a top elevational view of the branch graft of
FIG. 7A.
[0060] FIGS. 8A and 8B are cross-sectional views of second
embodiment of an endoaortic graft in accordance with the present
invention, with different attachment mechanisms for the magnetic
ring.
[0061] FIG. 9A is a cross-sectional view of a delivery system for
introducing the branch graft of FIG. 7A into a branch anatomic
conduit of a main anatomic conduit in accordance with another
embodiment of the present invention.
[0062] FIG. 9B is an enlarged perspective view of the distal end of
the delivery system of FIG. 9A.
[0063] FIGS. 10A-10DD illustrate the steps in the method for
endoluminal grafting of blood vessels or other tubular, main
anatomic conduits, in a region where one or more branch anatomic
conduits extend from the main anatomic conduit, using the
endoatoric graft, the endoaortic graft delivery system, the branch
anatomic graft, and the branch graft delivery system in accordance
with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0064] In describing preferred embodiments of the present invention
illustrated in the drawings, specific terminology is employed for
the sake of clarity. However, the invention is not intended to be
limited to the specific terminology so selected, and it is to be
understood that each specific element includes all technical
equivalents that operate in a similar manner to accomplish a
similar purpose.
[0065] The present invention provides a system and method for
endoluminal grafting of a blood vessel or other native, main
anatomic conduit, in a region where one or more branch anatomic
conduits (e.g., side branches, furcating, etc.) extend from the
main anatomic conduit.
[0066] In accordance with a first embodiment of the present
invention, the endoluminal grafting system 50 comprises an
endoaortic graft 100 (also referred to herein as an "endoaortic
cuff") (FIGS. 1A-1B), an endoaortic graft delivery system 200 for
introducing the endoaortic graft 100 into a native, main anatomic
conduit 10 (FIGS. 2A-2C), a branch graft 300 (FIG. 3), and a branch
graft delivery system 400 for housing the branch graft 300 and
introducing it into a branch anatomic conduit 20 extending from the
main anatomic conduit 10 (FIGS. 4A-4B).
[0067] As shown in FIGS. 1A-1B, the endoaortic graft 100 comprises
a first pliable tube (i.e., a tube formed of a pliable material)
having a lumen 112 extending longitudinally therethrough; at least
one branch opening 114 (e.g., an aperture) formed in the first
pliable tube 110; a flexible magnetic ring 120 incorporated around
the at least one branch opening 114 of the first pliable tube 110;
and an endoaortic graft anchoring device 130 for holding the first
pliable tube 110 in substantially fixed place within the main
anatomic conduit 10, such that the branch opening 114 is in
alignment with the branch anatomic conduit 20. The pliable material
can be woven polyester, expanded polytetrafluroethalene (ePTFE),
and other pliable, biocompatible materials. The endoaortic graft
anchoring device 130 can be, but is not limited to, such
conventional devices as a radially expandable stent, a frame, a
series of rings, and/or adhesive sutures, staples, etc.
[0068] The endoaortic graft 100 of the first embodiment of the
invention can have several embodiments. In a first embodiment,
shown in FIGS. 1A-1B, the flexible magnetic ring 120 is positioned
on, and is permanently secured to, the exterior surface of the
first pliable tube 110. In a second embodiment, shown in FIGS. 8A
and 8B, the flexible magnetic ring 120 is positioned on, and is
removably secured to, the interior surface of the first pliable
tube 110. The second embodiment may be preferable for smaller
grafts or other situations where it may not be desirable to leave
the magnetic ring in place. In the second embodiment, the flexible
magnetic ring 120 can be removably secured to the interior surface
of the first pliable tube 110 by flexible hooks 122 (FIG. 8A) or by
a friction fit with a flexible bushing 124 secured to the interior
surface of the first pliable tube 110 (FIG. 8B). One or more wires
140 are attached to the removable magnetic ring 120 for separating
the removable magnetic ring 120 from the flexible hooks 122 or
bushing 124 and withdrawing it from patient.
[0069] As shown in FIGS. 2A-2C, in accordance with the first
embodiment of the invention, the endoaortic graft delivery system
200 comprises a flexible outer sheath 210, which functions as a
delivery catheter, a flexible inner central sheath 220, at least
one flexible inner side sheath 230, and a tapered and flexible tip
240 at the distal end of the inner central sheath 220, the tip 240
forming the nose cone of the delivery system. The inner central
sheath 220 is substantially concentric with the outer sheath 210
for carrying an axial guide wire 30 (shown in FIGS. 10A-10J). The
at least one inner side sheath 220 is radially positioned between
the inner central sheath 220 and a corresponding branch opening 114
in the first pliable tube 110 for carrying a corresponding separate
branch anatomic conduit guide wire 40 (shown in FIGS. 10C-10J) that
is to be passed into a corresponding side branch anatomic conduit
20. The tapered, flexible tip 240 has an aperture 242 to allow the
passage of the axial guide wires 30 therethrough. The endoaortic
graft 100 is loaded in the endoaortic graft delivery system 200
such that the central sheath 220 carrying the axial guide wire 30
is centrally located therethrough, and the at least one inner side
sheath 220 carrying a corresponding branch guide wire 40 to a
corresponding branch anatomic conduit 20 is positioned within the
first pliable tube 110 downstream of the branch opening 114 and
traverses through the branch opening 114.
[0070] As shown in FIG. 3A, the branch graft 300 in accordance with
the first embodiment of the invention comprises a second pliable
tube 310 (i.e., a tube formed of a pliable material) having a lumen
312 extending therethrough and having a proximal end 314, a
mid-portion 316, and a distal end 318; a connector mechanism 320 at
the proximal end; and a branch graft anchoring device 330 at the
distal end 318. The second pliable tube 310 is sized to be
receivable through the flexible magnetic ring 120 of the endoaortic
graft 100 such that the junction between the branch graft 300 and
the endoaortic graft 100 is substantially fluid tight. The pliable
material can be woven polyester, expanded polytetrafluroethalene
(ePTFE), or other pliable, biocompatible material. The connector
mechanism 320 is made from a memory metal (such as nitinol) and is
associated with the proximal end of the second pliable tube. When
activated, the connector mechanism 320 is able to form a connection
with the corresponding branch opening 114 in the first pliable tube
110, such that the fluid that flows through the lumen 112 of the
first pliable tube 110 can pass through the branch opening 114 in
the first pliable tube 110 and into the lumen 312 of the branch
graft 300. The mid-portion 316 is configured with a corrugated
section 316a to maintain a patent lumen of the second pliable tube
310, such that the branch graft 300 is kink-resistant in an angular
situation. The branch graft anchoring device 330 is operative to
hold at least the distal end 318 of the branch graft 300 in contact
with the surrounding wall of the branch anatomic conduit 20. The
branch graft anchoring device 330 can be, but is not limited to, a
radially expandable stent, a frame, hooks, rings, sutures, staples,
and/or adhesive, staples.
[0071] As shown in FIGS. 4A-4B, in accordance with the first
embodiment of the invention, the branch graft delivery system 400
comprises an arrangement of three substantially concentric,
flexible, hollow sheaths, an outer sheath 410, an inner sheath 420,
and a middle sheath 430 between the outer and inner sheaths 410 and
420. Prior to deployment, the distal ends 422 and 432 of the inner
and middle sheaths 420 and 430 are substantially coterminous, and
the branch graft 300 is housed between the inner sheath 420 and the
middle sheath 430, so that the middle sheath 430 also covers the
branch graft 300. The outer sheath 410 cannot be retracted. At its
distal end 412, the outer sheath 410 carries a magnet 440. The
magnet 440 can have either a natural or an induced magnetic field,
and can include an electromagnet, a ferromagnet, or a ferromagnetic
fluid contained within a collar. The outer sheath 410 can also
rotate so as to change the polarity of the magnet 440 in a
particular plane, in order to disengage the branch graft delivery
system 400 from the endoaortic graft 100. The inner sheath 420
accommodates the guide wire going 40 into the branch anatomic
conduit 20 so that the entire branch graft delivery system 400 can
be passed over the guide wire 40. The distal end 422 of the inner
sheath 420 terminates in a tapered and flexible tip 450 forming the
nose cone of the branch graft delivery system 400. The tapered,
flexible tip 450 has an aperture 452 therein to allow the passage
of a guide wire 40 therethrough.
[0072] Because the middle sheath 430 covers both the inner sheath
420 and the branch graft 300, when the middle sheath 430 is
retracted, it will uncover the branch graft 300 such that the
branch graft 300 is deployed fully to form the new connection with
the endoaortic graft 100.
[0073] The branch graft delivery system 400 in accordance with the
first embodiment of the invention is suited primarily for use in
axial (straight line) situations, because the distal end is not
particularly flexible.
[0074] The above-described endoluminal grafting system 50 in
accordance with the first embodiment of the present invention can
be implanted within the branched anatomic conduit by a method
comprising the following steps:
[0075] 1) Advancing an axial guide wire 30 into the body of the
aneurysm (FIGS. 10A-10B), and then advancing at least one other,
more pliable balloon tipped guide wire 40 into the branch anatomic
conduit using the endoaortic graft delivery system 200 (FIGS.
10C-10I);
[0076] 2) Transluminally advancing the endoaortic graft 100 over
the guide wires 30 and 40 into the branched, main anatomic conduit
10 using the endoaortic graft delivery system 200 (FIGS.
10J-10M;
[0077] 3) Positioning the endoaortic graft 100 within the anatomic
conduit 10 using the endoaortic graft delivery system 200 such that
the branch opening 114 is aligned with the branch anatomic conduit
20 (FIGS. 10N-10P);
[0078] 4) Utilizing the endoaortic graft anchoring device 130 to
anchor the endoaortic graft 100 within the main anatomic conduit 10
(not shown);
[0079] 5) Transluminally advancing the branch graft 300 loaded in
the branch graft delivery system 400 over the guide wire 40 to the
branch anatomic conduit 20 (FIGS. 10Q-10R);
[0080] 6) Passing the distal end of the branch graft delivery
system containing the branch graft 300 through the branch opening
114 and into the branch anatomic conduit 20, until the magnetic
ring 120 of the endoaortic graft 100 and the magnet 440 on the
branch graft delivery system 400 attach (FIG. 10S);
[0081] 7) Operating the branch graft delivery system 400 such that
the branch graft 300 is deployed in the branch anatomic conduit 20,
until such time as the retractable middle sheath 430 of the branch
graft delivery system 400 is fully retracted (FIGS. 10T-10V);
[0082] 8) Once the retractable middle sheath 430 of the branch
graft delivery system 400 is fully retracted, rotating the outer
sheath 410 of the branch graft delivery system 400 by 180 degrees
to switch the magnetic poles to allow the two magnets 120 and 440
to disengage as well as deploy the most proximal part of the
nitinol connector mechanism 320, allowing the leak proof connection
between the branch graft 300 and the endoaortic graft 100 (FIGS.
10W-10DD).
[0083] In accordance with a second embodiment of the present
invention, the endoluminal grafting system 50' comprises an
endoaortic graft 100' (FIGS. 5A-5D), an endoaortic graft delivery
system 200 for introducing the endoaortic graft 100' into a native,
main anatomic conduit 10 (FIGS. 2A-2C), a branch graft 300' (FIGS.
7A-7B), and a branch graft delivery system 400 for housing the
branch graft 300' and introducing it into a branch anatomic conduit
20 extending from the main anatomic conduit 10 (FIGS. 4A-4B).
[0084] As shown in FIGS. 5A-5D, the endoaortic graft 100' comprises
a first pliable tube 110 (i.e., a tube formed of a pliable
material) having a lumen 112 extending longitudinally therethrough;
at least one branch opening 114 (e.g., an aperture) formed in the
first pliable tube 110; a flexible magnetic ring 120 incorporated
around the at least one branch opening 114 of the first pliable
tube; a coupling mechanism 150 for coupling the branch graft 300'
to the flexible magnetic ring 120; and an endoaortic graft
anchoring device 130 for holding the first pliable tube 110 in
substantially fixed place within the main anatomic conduit 10, such
that the branch opening 114 is in alignment with the branch
anatomic conduit 20. The pliable material can be woven polyester,
expanded polytetrafluroethalene (ePTFE), and other pliable,
biocompatible materials. The coupling mechanism 150 is as shown in
FIG. 5D and FIGS. 6A-6B, and comprises a plurality of staples 152
extending outwardly from the perimeter of the flexible magnetic
ring 120, and a plurality of struts 154 that hold the staples 152
in the open position and are releasable to allow the staples 152 to
close. The staples 152 preferably are made from a memory metal
(such as nitinol). The endoaortic graft anchoring device 130 can
be, but is not limited to, such conventional devices as a radially
expandable stent, a frame, a series of rings, and/or adhesive
sutures, staples, etc.
[0085] The endoaortic graft delivery system 200 of the second
embodiment of the present invention is the same as shown and
described in connection with the first embodiment.
[0086] As shown in FIGS. 7A-7B, the branch graft 300' comprises a
second pliable tube 310' (i.e., a tube formed of a pliable
material) having a lumen 312 extending therethrough, and having a
collapsible, toroidal-shaped proximal end 314' defining a connector
mechanism, a mid-portion 316, and a distal end 318; and a branch
graft anchoring device 330 at the distal end. The pliable material
can be woven polyester, expanded polytetrafluroethalene (ePTFE), or
other pliable, biocompatible material. The toroidal proximal end
314' can be a hollow silastic ring filled with a ferro-fluid (that
is, a fluid with magnetic particles suspended therein). The second
pliable tube 310' is sized to be receivable through the flexible
magnetic ring 120 of the endoaortic graft 100' such that the
junction between the branch graft 400 and the endoaortic graft 100'
is substantially fluid tight, and the ferro-fluid has sufficient
magnetic properties to be attracted to the flexible magnetic ring
120 yet still be easily movable relative thereto. The mid-portion
316 is configured with a corrugated section 316a to maintain a
patent lumen of the second pliable tube 310', such that the branch
graft 300' is kink-resistant in an angular situation. The branch
graft anchoring device 330 is positioned at the distal end 318 and
is operative to hold at least the distal end 318 of the branch
graft 300' in contact with the surrounding wall of the branch
anatomic conduit 20. The branch graft anchoring device 330 can be,
but is not limited to, a radially expandable stent, a frame, hooks,
rings, sutures, staples, and/or adhesive, staples.
[0087] The branch graft delivery system 400 of the second
embodiment of the present invention is the same as shown and
described in connection with the first embodiment.
[0088] The above-described endoluminal grafting system 50' in
accordance with the second embodiment of the present invention can
be implanted within the branched anatomic conduit 10 by a method
comprising the same steps (1) through (7) as in accordance with the
first embodiment, and the following additional steps:
[0089] 8) Once the retractable middle sheath 430 of the branch
graft delivery system 400 is fully retracted, rotating the outer
sheath 410 of the branch graft delivery system by 180 degrees to
switch the magnetic poles to allow the two magnets 120 and 440 to
disengage.
[0090] 9) Withdrawing the branch graft delivery system 400;
[0091] 10) Advancing another guidewire with a hook or snare
mechanism through the lumen 112 of the endoaortic graft 100';
[0092] 11) Under fluoroscopy, using the hook or snare mechanism to
engage the struts 154 of the endoaortic graft coupling mechanism
150 and apply traction to them to deploy the staples 150 and engage
the toroidal proximal end 314' of the branch graft 300'.
[0093] In accordance with a third embodiment of the present
invention, the endoluminal grafting system 50'' comprises the
endoaortic graft 100 of FIG. 1A-1B, 5A-5D or 8, the endoaortic
graft delivery system 200 shown in FIGS. 2A-2C, a branch graft 300
as shown in FIG. 3, and a branch graft delivery system 400' shown
in FIGS. 9A and 9B for housing and introducing the branch graft
300. The branch graft delivery system 400' of FIGS. 9A and 9B is
similar to that of FIGS. 4A-4B in also comprising an arrangement of
three substantially concentric, flexible, hollow sheaths, an outer
sheath 410, an inner sheath 420, and a middle sheath 430 between
the outer and inner sheaths, a magnet 440 carried at the distal end
412 of the outer sheath 410, and a nose cone 450 terminating the
distal end 422 of the inner sheath 420. However, in the endoaortic
graft delivery system 200 in accordance with the third embodiment
of the invention, prior to deployment, the distal end 422 of the
inner sheath 420 extends outwardly of the distal ends 412 and 432
of the outer and middle sheaths 410 and 430, with the branch graft
300 loaded over the distal end 432 of the middle sheath 430 with
only the connector mechanism 320 housed between the outer and
middle sheaths 410 and 430. Further, the branch graft delivery
system 400' includes means 460 for maintaining the branch graft 300
in a contracted condition prior to deployment.
[0094] In the third embodiment of the invention, the means 460 for
maintaining the branch graft 300 in a contracted position includes
a deployment wire 462 radially positioned between the inner and
middle sheaths 420 and 430, and a thread 464 wrapped around both
the contracted branch graft 300 and the deployment wire 462. The
thread 464 is made of a biodegradable, absorbable material (for
example, PTF or synthetic, absorbable suture sold under the
trademarks Vicryl.RTM. and Monocryl.RTM.). One end 464a of the
thread 464 is left as a tail extending at least the length of the
outer sheath 412 and the other end (not shown) is secured on
itself, for example by a half-knot, to prevent the wrapping from
unraveling. The thread 464 is wrapped about the deployment wire 462
and the branch graft 300 in a figure-eight configuration, so that
when the deployment wire 462 is retracted, the wrapping unravels,
allowing the branch graft 300 to assume an expanded condition.
[0095] The third embodiment of the invention, in which the branch
graft delivery system 400' employs a wrapping, is particularly
suited to use in a non-axial (curved) situation, as the distal end
of the branch graft delivery system 400' is relatively flexible,
although it can also be used in axial situations.
[0096] The above-described endoluminal grafting system 50'' in
accordance with the third embodiment of the present invention can
be implanted within the branched anatomic conduit 10 by a method
comprising the same steps (1) through (6) as in accordance with the
first embodiment, and the following additional steps:
[0097] 7) Operating the branch graft delivery system 400' such that
the branch graft 300 is deployed in the branch anatomic conduit 20,
until such time as the retractable middle sheath 430 of the branch
graft delivery system 400' is fully retracted;
[0098] 8) Once the retractable middle sheath 430 of the branch
graft delivery system 400' is fully retracted, rotating the outer
sheath 410 of the branch graft delivery system 400' by 180 degrees
to switch the magnetic poles to allow the two magnets 120 and 440
to disengage as well as deploy the most proximal part of the
nitinol connector mechanism 320, allowing the leak proof connection
between the branch graft 300 and the endoaortic graft 100.
[0099] Modifications and variations of the above-described
embodiments of the present invention are possible, as appreciated
by those skilled in the art in light of the above teachings. It is
therefore to be understood that, within the scope of the appended
claims and their equivalents, the invention may be practiced
otherwise than as specifically described.
* * * * *