U.S. patent application number 13/335742 was filed with the patent office on 2012-04-19 for modular grafting system and method.
This patent application is currently assigned to Endovascular Technologies, Inc.. Invention is credited to Timothy A.M. Chuter.
Application Number | 20120095547 13/335742 |
Document ID | / |
Family ID | 46204027 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120095547 |
Kind Code |
A1 |
Chuter; Timothy A.M. |
April 19, 2012 |
MODULAR GRAFTING SYSTEM AND METHOD
Abstract
A system and method for treating and repairing complex anatomy
characterized by a plurality of vessel portions oriented at various
angles relative to each other. The system including a graft device
that is capable of being assembled in situ and has associated
therewith a method that avoids the cessation of blood flow to vital
organs. A delivery catheter system and various graft supporting,
mating and anchoring structures are additionally included.
Inventors: |
Chuter; Timothy A.M.;
(Atherton, CA) |
Assignee: |
Endovascular Technologies,
Inc.
Menlo Park
CA
|
Family ID: |
46204027 |
Appl. No.: |
13/335742 |
Filed: |
December 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10949866 |
Sep 24, 2004 |
8105372 |
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13335742 |
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09780943 |
Feb 9, 2001 |
6814752 |
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10949866 |
|
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60187941 |
Mar 3, 2000 |
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Current U.S.
Class: |
623/1.35 |
Current CPC
Class: |
A61F 2002/061 20130101;
A61F 2/07 20130101; A61F 2002/075 20130101; A61F 2250/0039
20130101; A61F 2220/0075 20130101; A61F 2002/065 20130101; A61F
2/848 20130101; A61F 2/89 20130101; A61F 2220/005 20130101 |
Class at
Publication: |
623/1.35 |
International
Class: |
A61F 2/82 20060101
A61F002/82 |
Claims
1. A system for treating vasculature, comprising: a main component
having at least four apertures and at least two branch portions
that each have one of the apertures oriented in a substantially
reverse direction from an adjacent aperture at one end of the main
component; and at least two extension components each of which
including a portion configured to sealingly engage with one of the
apertures oriented in the substantially reverse direction.
2. The system of claim 1, wherein the main component has five
apertures.
3. The system of claim 1, the main component further comprising an
anchoring device attached to a superior end thereof, the anchoring
device comprising a generally sinusoidal frame and at least one
wall engaging member attached to the frame.
4. The system of claim 1, the main component further comprising an
anchoring device attached to an inferior end.
5. The system of claim 1, wherein the main component has a
generally tubular configuration with a superior end, a midsection
and an inferior end, a first aperture of the at least four
apertures positioned at the superior end, and a second aperture of
the at least four apertures positioned at the inferior end.
6. The system of claim 5, wherein the midsection of the main
component has a circumference which is less than a circumference of
each of the superior and inferior ends.
7. The system of claim 5, wherein the superior and inferior ends
have different circumferences.
8. The system of claim 5, further comprising an inferior extension
component.
9. The system of claim 9, the inferior end further comprising a
mating structure for mating with the inferior extension
component.
10. The system of claim 9, the mating structure further comprising
a suture routed about an interior circumference of the inferior
end.
11. The system of claim 8, the inferior extension component further
including a support structure extending a length thereof.
12. The system of claim 8, the inferior extension component further
comprising a first end, a second end and an anchoring device
attached to the second end.
13. The system of claim 8, the inferior extension component further
comprising a complimentary mating structure that engages a mating
structure of the main component.
14. A system for treating vasculature, comprising: a main component
including a superior end, an inferior end, and a midsection
including at least three limbs oriented in a substantially reverse
direction from the superior end or the inferior end, wherein each
of the superior and inferior ends and the limbs include an
aperture; and at least three limb extension components each of
which are configured to mate with one limb.
15. The system of claim 14, further comprising a series of delivery
catheters configured to deliver the main component and limb
extension components within vasculature.
16. The system of claim 15, wherein the main component and limb
extension components are assembled in situ.
17. The system of claim 16, wherein the superior end includes
structure that attaches within a first portion of a first vessel
and the inferior end includes structure that attaches to a second
portion of the first vessel.
18. The system of claim 17, wherein each of the limb extension
components include a mating end that engages an aperture of one
midsection limb and a second end for attachment to a vessel in
fluid communication with and extending at an angle from the first
vessel.
19. The system of claim 17, the main component further comprising a
supporting structure extending a length thereof.
20. The system of claim 17, the main component further comprising
an anchoring element attached to one of the superior or inferior
ends.
21. The system of claim 14, further comprising an inferior end
extender member configured to mate with the inferior end of the
main component.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/949,866, filed Sep. 24, 2004, which is a
divisional of U.S. patent application Ser. No. 09/780,943, filed
Feb. 9, 2001, now U.S. Pat. No. 6,814,752, which claims priority
from U.S. Provisional Patent Application Ser. No. 60/187,941, filed
on Mar. 3, 2000, the entire contents of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the treatment or repair of
vasculature and more particularly, to delivering a graft device
within a blood vessel to address vascular disease.
[0003] In recent years, there have been developments in the
treatment or repair of the vasculature of humans or other living
animals. These developments have been applied to various areas of
vasculature to treat a number of conditions such as vessel
weakening or narrowing due to disease. The methods developed have
involved minimizing the invasive nature of repair so that patient
morbidity and mortality can be reduced. The period of recovery has
also been reduced with such advances.
[0004] Some people are prone to degeneration and dilatation of the
aorta, leading to rupture and death from bleeding. A
recently-developed method of arterial reconstruction involves the
attachment of a tubular conduit (graft) to the non-dilated arteries
above and below the degenerated segment using stents; hence the
name "stent-graft" for the prosthesis. The lumen of the arterial
tree is used as a conduit to the aorta; hence the name
"endovascular aneurysm repair" for the procedure.
[0005] The procedure is relatively simple when the degenerated
segment is without significant branches. The stent-graft needs only
one lumen with an orifice at each end. But the procedure is much
more complicated when the degenerated segment of the aorta contains
branches, because the stent-graft also needs to branch and these
branches need to be placed along multiple lines of insertion. The
most common, and simplest, example is reconstruction of the aortic
bifurcation. This technical hurdle was crossed relatively early.
Yet there has been no significant progress in the intervening years
towards reconstruction of areas with more branches, such as the
suprarenal aorta, the aortic arch, or other complex vasculature
near the kidneys or involving the hypogastric, iliac or femoral
arteries. The main problem is that the branches are of variable
size, variable orientation, and variable position. It is very
difficult to create a graft that will mimic the native anatomy, and
very difficult to place such a graft in exactly the right
orientation and right position without causing ischemia of the
vital organs that are fed by the aortic branches. This is
especially true of the aortic arch, which has branches to the
brain.
[0006] The aortic arch, for example, is affected by two
degenerative processes, dissection and aneurysmal dilatation, that
hitherto have been treated by open surgical reconstruction. The
open surgical operation relies upon cardiopulmonary bypass, with or
without hypothermic circulatory arrest. The associated mortality,
morbidity, debility, pain and expense are all high.
[0007] Endovascular methods of reconstruction must deal with
certain challenging anatomic features. For example, all three
arteries that take origin from the aortic arch supply blood to the
brain. Flow through these arteries cannot be interrupted for more
than five minutes without risking irreversible neurologic damage.
Moreover, the distribution of the arteries in any one patient, and
the arch arteries, in particular, is highly variable. It is,
therefore, not feasible to mimic this arrangement in every patient
without very sophisticated reconstruction. Even if the graft
matched the patient's anatomy precisely, it would still be
difficult to match the orientation and position of the branches of
the graft to the branches of the native vasculature. Additionally,
the arch arteries, for example, usually arise from the ascending
portion of the arch at acute angles to the downstream aorta.
Trans-femoral access to the arch arteries necessitates a sharp
change of direction where these arteries arise from the aorta.
[0008] However, certain anatomic features lend themselves to
endovascular repair. The aorta and in particular, the ascending
aorta is long, straight and without significant branches. Further,
the aorta is wide and consequently, there would be room for a main
or primary graft conduit to lie alongside its branches. Also, it is
relatively easy to gain access to the femoral and iliac
arteries.
[0009] Accordingly, what is needed and heretofore unavailable is a
system and method for treating or repairing complex vasculature
while minimizing risk and the recovery time of the patient. The
present invention meets these and other needs.
SUMMARY OF THE INVENTION
[0010] Briefly and in general terms, the present invention is
directed to a device and method for treating or repairing diseased
vasculature. The invention provides a minimally invasive approach
to the treatment of complex vasculature characterized by a first
vessel in fluid communication with a plurality of vessel portions
extending at various angles from the first vessel. The present
invention is also concerned with treating or repairing vessels
which are difficult to access and which supply blood to vital
organs which require a continuous source of blood and accordingly,
avoids complexities associated with simultaneous insertion and
deployment of multiple components.
[0011] The present invention embodies a graft device having a
superior end, an inferior end, a midsection and a plurality of
apertures. Each of the apertures of the grafting device are capable
of being aligned with or placed in the relative vicinity of a
vessel portion to enable an exterior component to extend from the
grafting device to the vessel portion to enable an extension
component to extend from the grafting device to the vessel portion.
In one aspect, the superior and inferior ends of the graft device
each include apertures and are configured within a first vessel
portion and each of the apertures formed in the midsection are
aligned with blood vessel portions extending at an angle from the
first vessel. Further, it is contemplated that the graft device
includes a main component and a plurality of extension components
that are configured to mate with the main component. Various
anchoring, mating and support structures are also contemplated that
facilitate securing the graft device within vasculature for
accomplishing repairing complex vessel anatomy. Occlusion
structures are also included that can be used to close off one or
more unused graft device apertures.
[0012] Additionally, the present invention embodies a delivery
catheter system and method that accomplishes the deployment and
attachment of the graft device within vasculature. The delivery
catheter system includes structure for receiving the various
components of the graft device of the present invention as well as
a series of guidewires which provide a path taken by components of
the delivery catheter system.
[0013] It is contemplated that a branched stent-graft of the
present invention be constructed in-situ from multiple components,
a main or primary stent-graft with multiple short branches and
several branch extensions. Variations in arterial anatomy are
accommodated intraoperatively through the independent selection of
components as indicated by intraoperative measurements.
[0014] In one aspect, the device does not attempt to mimic native
anatomy. For example, the widest portion of the primary stent-graft
is attached (usually with a stent or an anchoring device) to the
proximal aorta. All branches of the primary stent-graft originate
at a level proximal to the branches of the aorta. The variable gap
between branches of the stent-graft and branches of the aorta is
accommodated by variation in the length of the extensions. Thus,
several extensions run next to one another through the proximal
aortic segment. This is possible because the central section of the
primary stent-graft is sized to be much smaller than the native
aorta in the region of the aortic branches. The space around the
central section also allows for blood flow from the stent-graft
branches to the aortic branches and continuing perfusion of the
vital organs while extensions are added one by one. A distal aortic
seal is established through a slightly wider segment.
Alternatively, additional components can be added with their own
branches to permit extension into other aortic branches, such as
the iliac arteries.
[0015] The extensions can be fully-stented (lined from one end to
the other with stents or some other means of support), yet
flexible. As so configured, they maintain a stable position through
a combination of stent support and anchoring or attachment
mechanisms at both ends.
[0016] The two main sites requiring this kind of treatment are the
aortic arch and the suprarenal aorta. The present invention also
has applications in other complex anatomy including the iliac,
hypogastric or femoral arteries. Although the principles are the
same for such sites, differences in anatomy necessitate differences
in basic technique. For example, in the arch, the extensions are
introduced through the branch arteries, while in the suprarenal
aorta the extensions are introduced through the stent-graft from a
point of peripheral arterial access in the upper body, usually the
left upper limb.
[0017] In a preferred embodiment of the present invention, the
trunk of the primary stent-graft is bone-shaped with three
segments; a narrow central segment and wider segments at both ends.
The wider segments are large enough to engage the aorta. Typical
diameters are 3.5-4.5 cm proximally and 2.5-3.5 cm distally. The
central segment is smaller (approx. 2 cm). Three stent-graft limbs
or branches arise from the transition zone between the proximal and
middle segments. These are also small (approx. 1 cm). Their origins
are staggered at 1 cm intervals both down the length of the trunk
and around its circumference.
[0018] In one embodiment, there is a self-expanding anchoring
device or stent in each of the five stent-graft orifices. Flexible
bracing wires run along the outer aspect of the stent-graft between
all five stents, so that each segment of the stent-graft is held to
a fixed length. Guidewires run alongside the central catheter of
the delivery system and through the stent-graft, entering through
an inferior or distal orifice and exiting through the orifices of
the branches to run back down the outer aspect of the stent-graft.
At the base of each branch of the stent-graft there are several
circumferential suture loops that form part of a stent-graft to
stent-graft mating or attachment system.
[0019] Long, flexible, narrow, fully-stented stent-graft extensions
exist in a range of lengths and diameters. Each has an external
grappling mechanism on the outer aspect of the graft near the
proximal tip. The inner 2-3 cm of the extension is sized to match
the diameter of the primary stent-graft branch (approx. 1 cm). The
rest of the extension is sized to match the diameter of the arch
artery.
[0020] The stent-graft is inserted through a flexible sheath into
the arch of the aorta from an access point in the femoral artery.
When released from its sheath, the stent-graft expands. A catheter
is advanced over one of the guidewires, through the trunk of the
stent-graft and out of one of the branches. The guidewire is then
withdrawn and directed into a waiting snare that was previously
inserted into the aorta through corresponding arch artery. The
distal stent-graft branch corresponds to the left subclavian
artery, the middle stent-graft branch corresponds to the left
carotid artery and the proximal stent-graft branch corresponds to
the innominate (brachiocephalic) artery.
[0021] The femoro-brachial guidewires are used to insert calibrated
catheters into the proximal aorta through the stent-graft branches.
Angiography through the calibrated catheter allows the selection of
a suitably sized extension. Each calibrated catheter is then
exchanged (over the wire) for the delivery systems of the
corresponding stent-graft extension. The extension is deployed
within the stent-graft branch where it is secured by the friction
generated by the outward pressure of its stents and by the
interaction of the grappling mechanism with the loops of the
stent-graft branch.
[0022] In other embodiments, the application of the present
invention relates to treating complex vasculature involving the
iliac, femoral, and hypogastric arteries. Various approaches are
contemplated to accomplish the in-situ assembly of components of
the graft device of the present invention.
[0023] Other components of the present invention include employing
stents with a very high expansion ratio which are flexible and have
a low profile. Various methods of accomplishing secure stent-graft
to stent-graft attachment are also contemplated as are various
methods of providing a graft component with a desired flexibility
and radial strength.
[0024] These and other objects and advantages of the invention will
become apparent from the following more detailed description, when
taken in conjunction with the accompanying drawings of illustrative
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a perspective view, depicting one component of a
graft device of the present invention;
[0026] FIG. 2 is a perspective view, depicting one embodiment of an
anchoring device of the present invention;
[0027] FIG. 3 is a perspective view, depicting a second embodiment
of an anchoring device of the present invention;
[0028] FIG. 4 is a perspective view, depicting a support structure
of the present invention;
[0029] FIG. 5 is a cross-sectional view, depicting one embodiment
of mating structures of a component of a graft device of the
present invention;
[0030] FIG. 6 is a cross-sectional view, depicting a second
embodiment of mating structure of a component of a graft device of
the present invention;
[0031] FIG. 7 is a cross-sectional view, depicting a third
embodiment of mating structure of a component of a graft device of
the present invention;
[0032] FIG. 8 is a perspective view, depicting one embodiment of
grappling or corresponding mating structure attached to a component
of the graft device of the present invention;
[0033] FIG. 9 is a partial cross-sectional view, depicting a first
stage of deployment of a graft device of the present invention
within vasculature;
[0034] FIG. 10 is a partial cross-sectional view, depicting a first
stage of deployment of a graft device of the present invention
within vasculature;
[0035] FIG. 11 is a partial cross-sectional view, depicting a third
stage of deployment of a graft device of the present invention
within vasculature;
[0036] FIG. 12 is a partial cross-sectional view, depicting a
fourth stage of deployment of a graft device of the present
invention within vasculature;
[0037] FIG. 13 is a partial cross-sectional view, depicting an
alternative embodiment of one component of a graft device of the
present invention;
[0038] FIG. 14 depicts a first stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0039] FIG. 15 depicts a second stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0040] FIG. 16 depicts a third stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0041] FIG. 17 depicts a fourth stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0042] FIG. 18 depicts a fifth stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0043] FIG. 19 depicts a sixth stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0044] FIG. 20 depicts a seventh stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0045] FIG. 21 depicts a eighth stage in deployment of another
embodiment of a component of the graft device of the present
invention;
[0046] FIG. 22 depicts a ninth stage in deployment of another
embodiment of a component of the graft device of the present
invention; and
[0047] FIG. 23 depicts a graft device of the present invention in
combination with an occlusion device.
DETAILED DESCRIPTION OF THE INVENTION
[0048] As shown in the drawings, which are included for purposes of
illustration and not by way of limitation, the present invention is
embodied in a system and method for treating or repairing complex
vasculature that feeds vital body organs. In one aspect of the
invention, disease affecting the vasculature proximal the aortic
arch is addressed while in other aspects, disease affecting complex
vasculature including the thoracic, renal, iliac, femoral or
hypogastric arteries is addressed. It is contemplated that an
approach involving an in-situ assembly of a modular graft device be
employed to treat or repair such vasculature. Accordingly, various
anchoring, mating, and support structures are contemplated as well
as a delivery catheter system for accomplishing the deployment of
the same. Further, the present invention provides a minimally
invasive technique for addressing disease by avoiding conventional
invasive surgery that has heretofore been required to repair highly
complex portions of vasculature.
[0049] Referring now to FIG. 1, there is shown one application of
the present invention. As shown in FIG. 1, the present invention
includes a first or main graft component 50. The main graft
component 50 embodies a generally tubular shape involving a
superior end portion 52, an inferior end portion 54, and a
midsection 56. Each of the superior 52 and inferior 54 end portions
includes openings or apertures 58, 60. Additionally, the main graft
component 50 includes a plurality of limbs 62, 64, 66 extending in
an inferior direction (though they can extend in various and varied
other directions) from a superior end portion of the main component
50. Each of the limbs 62, 64, 66 include openings or apertures 68,
70, 72 at terminal ends of the limbs 62, 64, 66. Although the
figures depict three such limbs, fewer or more limbs may be
provided for a particular purpose. The limbs can be different
lengths and can be located at different axial and circumferential
locations along the main graft.
[0050] To minimize the outer profile of the main component 50 and
to otherwise provide a space for the limbs 62, 64, 66 and other
components of the present invention, the midsection 56 of the main
component 50 is narrowed with respect to the superior 52 and
inferior 54 ends. That is, the midsection 56 has a circumference or
radial dimension less than that of the superior 52 and inferior 54
ends, whereas the superior 52 and inferior 54 ends can have the
same or different circumferences or radial dimensions. A transition
section 74 is included medial each of the superior 52 and inferior
54 end portions whereat the circumference of the graft device
narrows to that of the midsection 56. The circumference or radial
dimension of the limbs 62, 64, 66 is generally less than that of
the midsection section 56 and the limbs 62, 64, 66 can have equal
or varied circumferences.
[0051] The main component can be fabricated by any convention means
whether it be assembling separate pieces of graft material into a
desired configuration or employing various weaving techniques to
thereby have a one piece design. In one preferred approach of
manufacture, several tubular pieces of standard vascular material
can be attached to each other using suture. Further, the trunk
(superior, inferior, and midsection portions) and limbs can embody
woven polyester or PTFE folds or areas of double layers of material
can be added as required to attach anchoring, grappling or support
structures to the graft component.
[0052] In the present invention, it is contemplated that the
superior end portion 52 be configured with an anchoring device 76
that operates to attach the main component 50 within vasculature.
The anchoring device 76 can be placed or attached to an interior or
an exterior of the main component 50 and can assume various forms.
Additionally, the main component 50 can include support structures
extending the entire length or a portion of the length of the main
component 50 and various structures for mating with other graft
components. The anchoring device can be within the length of the
main graft or extend beyond the end of the graft as shown.
[0053] With reference to FIGS. 2 and 3, there is shown two forms of
anchoring devices which may be used, although other forms can be
employed as necessary. As shown in FIG. 2, a generally sinusoidal
anchoring device 80 including a plurality of alternating apices 82
configured with torsion springs 84 and wall engaging members 86
attached to members 88 connecting the apices 82 is one acceptable
device for attaching the graft component 50 within vasculature.
Another acceptable anchoring device 90 (FIG. 3) is embodied in a
flat wire frame 92 that has alternating apices 94, curved members
96 connecting the apices 94 and wall engaging members 98 extending
from selected apices 94. Each of these devices 80, 90 can be
attached to any portion of the main component 50 or other
components which mate with the main component 50, by sewing or
gluing or spot deformation welding, for the purpose of anchoring
such graft components to vasculature. Further, these devices 80, 90
can be self-expanding or manufactured so that a radial force is
required for expansion.
[0054] Moreover, with reference to FIG. 4, the main component 50 or
other components mating therewith may include support structure 100
configured about an exterior circumference or internal bore of the
particular component. One such support structure 100 may include a
flat wire framework defining a plurality of connected and embedded,
generally almond-shaped apertures 102. The members 104 defining the
almond-shaped apertures 102 are curved in a manner to optimize
radial expansion and strength while providing a small profile when
compressed. The ends 104, 106 of the support structures 100 is
defined by a plurality of apices 108 of the almond-shaped apertures
102 and members 104 defining half-almond shaped gaps 110. Such a
support structure 100 can be manufactured to be long enough to
support the entire length of a graft component or a plurality of
support structures having a desired length can be placed in series
along the particular graft component to provide the longitudinal
and axial flexibility desired for a particular application.
Generally, it is contemplated that the support structure 100 is
self-expanding; however, it may be desired that for certain
applications, a balloon catheter can be utilized to expand the
support structure 100.
[0055] It is also contemplated that support structures can embody a
modified form of the device shown in FIGS. 2 and 3. That is,
acceptable support structures can embody the sinusoidal frame
without the wall engaging members 86 of the anchoring device 80
shown in FIG. 2 or the flat wire frame 92, without wall engaging
members 98, of the anchoring device 90 shown in FIG. 3. In both
cases, a series of such devices can be placed along a selected
length of a particular graft component.
[0056] Additionally, in other embodiments a bracing device (not
shown) in the form of an elongate wire or equivalent structure can
be configured between anchoring devices or other support structures
attached to a graft component. The bracing device is intended to
provide the particular graft component with longitudinal stiffness
and pushability.
[0057] Although the anchoring, support, and bracing wire structures
can be made from radiopaque material, radiopaque markers can also
be added to components of the graft device of the present
invention. Such markers can be sewn into material used to
manufacture the particular graft component. The radiopaque markers
or other radiopaque structures are used during the advancement and
deployment of a graft component within diseased vasculature. High
resolution imaging is employed to view such a procedure.
Fluoroscopy and other remote imaging techniques are also
contemplated to accomplish the viewing of the radiopaque structures
during an implant procedure.
[0058] Turning now to FIGS. 5-7, there is shown various mating
structures for mating or connecting one portion of one graft
component to another graft component. With reference to FIG. 5, a
first embodiment of mating structure 120 includes a suture 122 that
is configured about an interior circumference of a graft component
123. The suture 122 is configured into a plurality of loops 124 by
connecting multiple point locations thereof to the graft component
123 by any suitable means such as rings or other suture material
126. Although the suture 122 is shown routed about an interior of
the graft component 123, it can likewise be attached to an exterior
thereof. In either case, the mating structure 120 is adapted to
engage a framework extending radially outwardly from another graft
component.
[0059] A similar approach is shown in FIGS. 6 and 7. The mating
structure 130 depicted in FIG. 6 embodies a circumferential fold
132 formed in a graft component 133, the fold 132 being held in
place with clips or sutures 134 or any other equivalent means.
[0060] As shown in FIG. 7, the mating structure 140 can be defined
by a framework 142 having opposing or alternating apices 144 and
can be affixed to an interior (or exterior, as needed)
circumference of a graft component 145 by sutures or equivalent
structure 146. In one aspect, the apices 144 at a superior end 148
of the support structures 140 are intended to extend slightly
radially inwardly so that a suitable engaging surface is provided.
It is to be recognized that various forms of framework can be
employed as such a mating structure provided the desired mating
function is accomplished.
[0061] Moreover, the mating of two components of a modular graft
can be accomplished through the frictional engagement of an outer
circumference of one component with an inner circumference of
another component. Such a frictional engagement can rely on surface
irregularities or other more defined projections or can employ
adhesives. It is also contemplated that structures such as that
depicted in FIGS. 2 and 3 can be used to join two components. The
wall engaging members 86, 98 of those structures 80, 90 are
contemplated to lock the components together by penetrating the
walls defining the components being joined. The expansion of the
structures 80, 90 also add in maintaining a sealed connection.
[0062] As shown in FIG. 8, a typical extension component 150 can
embody a generally tubular shape. However, it is also contemplated
that a limb component can also be bifurcated or trifurcated. The
extension components can be made of any suitable conventional
material. In one preferred embodiment, the extension components are
made of PRFE.
[0063] A mating end 152 of a typical extension component is
provided with some foem of projection or grappling mechanism for
engaging the corresponding mating structure of another graft
component. In FIG. 8, there is shown one embodiment of an
acceptable grappling or mating structure 154, although various
other forms are possible. The mating structure 154 can include a
self-expanding or balloon expandable framework defined by opposing
apices 156 and can be attached to a graft component 150 by
conventional methods such as suturing. One end 158 of the mating
structure 154 embodies apices 156 which project radially outwardly
from and around the outer circumference of the graft component 150.
Such structure can alternatively be placed about an interior
circumference for a particular application. Being so configured,
the extension component can be placed within or about another graft
component so that the corresponding mating structures are placed
beyond each other and then the components can be moved relative to
each other so that they overlap and sealingly engage.
[0064] One application of the present invention is to treat or
repair diseased vasculature involving the aortic arch (See FIGS.
9-12). Since such vasculature varies from patient to patient, an
attempt to mimic the nature vessel anatomy is not made. Rather, the
graft device of the present invention is assembled in-situ in a
manner to maintain blood flow through the various branches of the
anatomy by extending graft conduits from a main component to the
necessary locations. Blood thereby flows through the graft device
rather than through the diseased vasculature.
[0065] For example, the widest or superior portion 52 of the
generally bone-shaped main graft or primary stent-graft component
50 is attached to the proximal aorta 162 (FIG. 9). Typically, the
main graft component 50 has a diameter of 3.5-4.5 cm at the
superior end 52, 2.5-3.5 cm at the inferior portion 54 and about 2
cm at the midsection 56. All branches or limbs 62, 64, 66 of the
main component 50 have a diameter of about 1 cm and originate at a
point proximal (closer to the heart) to the branches 164, 166, 168
of the aorta 162 to be treated. The origin of the limbs 62, 64, 66
can be staggered at about a 1 cm interval as shown in FIG. 9 or can
originate generally at the same longitudinal location. Where the
objective is to treat the aortic arch, for example, the relatively
narrow midsection 56 provides a space for the various limbs 62, 64,
66 as well as a space for blood flow during the implant procedure,
thereby providing continuous perfusion of blood to vital organs and
the innominate (brachiocephalic) artery 164, the left carotid
artery 166 and the subclavian artery 168.
[0066] In order to deliver the main component 50 within the aortic
arch 162, a conventional delivery catheter (not shown) can be
employed. Such a delivery catheter will embody a device or
structure for accomplishing relative movement between the main
component and the delivery catheter and deployment of the main
component from the catheter such as withdrawing a jacket from over
the device. It is also desirable to take a femoral approach and to
advance the assembly over a guidewire and through branch arteries
to reach the aortic arch.
[0067] In one preferred method, the delivery system involves a
plurality of guidewires 170, 172, 174. The catheter (not shown)
retaining the main component 80 is advanced over the guidewires
170, 172, 174, each of which are individually routed through the
interior end 54 of the main graft component 50 and out one limb
164, 166, 168. Deployment involves the attachment of an anchoring
device such as those shown in FIGS. 2 and 3 which is affixed to the
superior portion 52 of the main component 50. Thereafter, a
catheter 180 is advanced over a first guidewire 170. The guidewire
170 is then withdrawn and directed with the aid of the catheter 180
proximate to the proximal branch artery 164. Contemporaneously, a
small end hole device 190 embodying an outer sheath 192 and a
looped grasping terminal end 194 is placed within the patient's
body through a peripheral artery and advanced to within and beyond
the proximal branch artery 164 into the aortic arch 162.
[0068] Through relative movement between the looped terminal end
194 and the sheath 192 of the snare device 190, the looped terminal
end 194 is placed in a position to grasp the first guidewire 170.
After grasping the guidewire 170, it is used to insert a calibrated
catheter 200 into the proximal aorta 162 through the first limb 62
(See FIG. 11). The calibrated catheter is utilized to select a
suitably sized limb extension for mating with the main component
50.
[0069] Next, the calibrated catheter 200 is exchanged (over the
wire) for an extension component delivery system 210 which is
adapted to retain an extension component 220 in a compressed state
as well as with structures for accomplishing relative longitudinal
movement therebetween (See FIG. 12). Mating or sealing of a
superior or proximal end 222 of the limb extension 220 is
accomplished through the engagement between grappling structures
such as that shown in FIG. 8 attached thereto with mating
structures such as those shown in FIGS. 5-7 which are attached to
an interior circumference of the first limb 62. The inferior or
distal end 224 of the extension component 220 is equipped with
anchoring devices such as those shown in FIGS. 2 and 3. The
expansion of the anchoring devices accomplishes the affixation of
the limb component 220 to the first branch artery 164.
[0070] A similar procedure is employed to attach limb extension to
the second 64 and third 66 limbs of the main graft component 50.
Additionally, similar mating and grappling and anchoring devices
are used to assemble the graft device in-situ. As stated
previously, each of the components of the modular graft assembly
can include support structures extending a portion or entire length
thereof to provide a desired flexibility and radial strength. The
graft assembly can also embody the previously described bracing
devices. The limb extensions themselves are designed to have a
length of approximately 2-3 cm sized to match the 1 cm diameter of
the limbs of the graft, whereas the rest of the length thereof
matches the diameter of the particular branch artery.
[0071] The superior end portion 54 (See FIG. 9) of the main
component 50 can be configured with an anchoring device 80, 90
(FIGS. 2, 3) for direct attachment to the aorta. Alternatively, the
inferior end portion 54 can be equipped with mating structures 120,
130, 140 (FIGS. 5-7). When equipped with such mating structures
120, 130, 140, a further tubular, bifurcated or trifurcated
inferior extension can be mated therewith. When assembled at the
aortic arch, the graft assembly is intended to provide a complex
conduit for blood flow. As such, disease occurring at the arch is
treated and the vasculature is repaired.
[0072] In certain situations, the ascending aorta 230 is less than
6 cm in length thereby leaving insufficient room to both anchor the
superior end portion 52 of the main component upstream of a first
or proximal branch 164 and provide space for the limbs 62, 64, 66
(FIG. 13). In order to avoid compromising the sealing and anchoring
of the superior end portion 52, the limbs can be invaginated to
provide an internal docking site for limb extensions. The mating
structures can be rearranged as necessary and the limbs can be
supported or braced as necessary to accomplish sufficient sealing
between graft components.
[0073] As stated, the present invention can be applied to various
complex vasculatures throughout a patient's body. For example, the
present invention can be used to treat aneurysms or stenoses found
in the iliac, SMA, SFA or renal arteries. Moreover, aneurysms found
in the thoracic region of the aorta are now treatable using the
repair system of the present invention.
[0074] If left untreated, a thoracoabdominal aortic aneurysm (TAAA)
is associated with reduced life expectancy from ruptures. Open
surgical aneurysm repair eliminates the risk of ruptures at the
expense of high mortality and morbidity rates. Despite obvious
advantages over the current alternatives, endovascular repair of
TAAA is feasible only if flow can be maintained to all the vital
branches of the proximal abdominal aorta, while redirecting flow
away from the aneurysm.
[0075] The use of multi-limbed unibody grafts to repair TAAA has
potential problems. The relative orientation of the graft limbs
reflects the relative origination of the guiding catheters employed
to deliver the graft to the repair site. If the catheters twist
around one another on their way from the femoral artery to the
aorta, the branches of the unibody graft do as well. In addition,
once such a graft is deployed, visceral perfusion depends on branch
deployment and any delay thereof produces ischemia.
[0076] In order to determine the feasibility of endovascular repair
of TAAA, CT and calibrated catheter angiography are employed.
Measurements and the mapping of the target anatomy are taken and
recorded. Graft components can then be assembled and sizes selected
as necessary to be later used in a repair procedure.
[0077] It is contemplated that TAAA repair involves prolonged
periods of magnified high resolution imaging, during which the
field ranges back and forth from the neck to the groin of the
patient, while the view ranges from full left lateral to full right
lateral and every angle therebetween. The patient lies in a supine
position under general endotracheal anesthesia. Arterial access is
obtained through the femoro-brachial arteries by making oblique
incisions, although longitudinal incisions can also be made.
Heparin is given intravenously to maintain the activated clotting
time at twice control from arterial puncture to arterial repair. In
addition, heparinized saline is infused slowly through all
individual sheaths used during the implant procedure and evoked
potentials are continuously monitored. If there is a noticeable
change, cerebral spinal fluid (CSF) is drained through a lumbar
catheter and blood pressure can be supported pharmacologically to
improve spinal perfusion.
[0078] With reference to FIGS. 14-22, various steps in treating or
repairing a TAAA is described. As shown in FIG. 13, similar to the
previously described graft devices, a main component 350 used in
treating a TAAA embodies a superior end portion 352, an inferior
end portion 354, and a midsection 356, as well as a plurality of
limbs 362, 364, 365, 366. As before, the main component 350 is made
from conventional fabric. An oblique anastomotic line joins the
superior portion 352 to the limbs 362, 364, 365, 366 and inferior
end portion 354. The limbs 362, 364, 365 and 366 are staggered
longitudinally along the main component 350 and the midsection is
tapered with respect to the superior end portion 352 to provide
space for the limb. The inferior end portion 354 can have a much
smaller diameter to provide space for mating with limb
extensions.
[0079] The diameters of the various parts of the main component
depend on the anatomy of the vasculature being repaired. For
instance, the overall diameter is oversized 4-6 mm more than the
thoracic aortic implantation site whereas the limbs have diameters
approximating the aortic branches and the distal lumen is 20 mm in
diameter. Moreover, the length of the main or first component 350
varies according to the extent of involvement of the descending
thoracic aortic 400. It is contemplated that there be about a 2.5
cm overlap with healthy proximal aorta and the main component 350,
2 cm overlap between side branches 402, 404, 405, 406 and extension
components (described below) and 1-2 cm gap between terminal ends
of the limbs 362, 364, 365, 366 and the side branches 402, 404,
405, 406. The shorter the gap the more difficult it can be to
accommodate errors in orientation. However, the longer the gap, the
greater the risk that an extension component will blow out leading
to kinking or dislocation and failure. Moreover, if a limb is below
a corresponding branch artery, it is very difficult to add an
extension component. Accordingly, pre-sizing is of utmost
concern.
[0080] An anchoring device 380, which can take various forms such
as shown in FIGS. 2, 3 and 13, is affixed to a terminal end of the
superior end portion 352. The main or first component 350 can be
fully supported, including the limbs, with the structures
previously described or many include one or more discrete support
structures placed therealong. Such structures can be placed about
an outer circumference or inner circumference of the graft. The
limbs can be unsupported except at their ends initially and then
support structures can be placed in them later. Moreover, each of
the four limbs 362, 364, 365, 366 (See FIG. 18 for limb 365 not
shown in FIG. 14) can be equipped with mating structures such as
those shown in FIGS. 5-7. Additionally, as before, radiopaque rings
or markers can be placed along the inside or outside of various
components of the graft device of the present invention. These can
aid in assembling as well as orientating the graft device within
vasculature.
[0081] Delivery of the main component 350 within the target site
requires a sheath such as a large bore 20-24 French sheath. Any
conventional delivery catheter so equipped can be employed. Such
conventional catheters may further include an expandable or
inflatable member for opening or implanting the support and
anchoring devices attached to the main component 350. The delivery
catheter is additionally contemplated to include structures or
means for accomplishing relative longitudinal movement between the
main component 300 and the delivery catheter in order to facilitate
deployment and implantation. Conventional guidewires are also
contemplated for providing a path taken by any of the delivery
catheters used to deploy components of the graft device of the
present invention.
[0082] In operation, the main component 350 is advanced to a
desired level within the thoracic aorta 400 and rotated to align
the limbs 362, 364, 365 and 366 with their corresponding branch
arteries. A trans-brachial catheter (not shown) can be used for
angiographic localization of the branch arteries. The goal is to
position the terminal ends of the limbs 362, 364, 365, 366, 1-2 cm
above the corresponding branch artery.
[0083] With specific reference to FIGS. 15-19, there is shown a
preferred procedure for attaching or overlaying a limb extension
452 with a limb 362 of the main or first component 300. As
described above, the limb extensions 452 can be fully supported
with the devices shown in FIGS. 2-5, 15-22 about an interior or
exterior of a particular limb extension 452. The limb extensions
are also equipped with grappling or corresponding mating structures
(See FIG. 7, for example) configured to engage structures or
devices affixed to the limbs 362, 364, 365, 366.
[0084] Limb extensions 452 are contemplated to be inserted through
a surgically exposed brachial artery, right or left, depending upon
the aortic arch anatomy. In theory, right-side access carries a
greater risk of stroke, but it sometimes provides a less tortuous
route to the descending thoracic aorta 400. As shown in FIG. 15, a
guiding catheter 500 is inserted from the brachial artery to the
proximal descending thoracic aorta 400. This helps guide the
catheter 500 through the aortic arch and minimizes the risk of
stroke. The catheter 500 is further positioned through an opening
358 found in the superior end portion 352 of the main component 350
and out an opening or aperture 368 formed in a terminal end of a
first limb 362. At this time, a small volume of contrast can be
injected to confirm sheath positioning. Depending on the target
anatomy, a small radius J-tip catheter 502 can be advanced over a
previously placed guidewire and utilized for directing the catheter
500 within the proper branch artery 402, the catheter providing a
means of angiography and atraumatic passage into the branch artery.
Power injection of full strength contrast (20 ml at 20 ml/s) can be
used to more clearly show the anatomy.
[0085] The guiding catheter 500 is then replaced with a 12 French
endhole sheath 504 (FIG. 16). Next a delivery catheter 506
retaining a limb extension 452 (FIG. 17) is advanced within the
sheath 504 and positioned within the target branch artery 402. The
delivery catheter 506 is contemplated to be equipped with structure
or means, such as a pusher device to accomplish relative
longitudinal movement of the catheter and limb extensions 452 and
to release the same at the target site (FIGS. 18, 19). The delivery
catheter 506 can further include an expandable or inflatable member
508 which is provided to facilitate implantation of the limb
extension 452.
[0086] The foregoing is repeated until a bridge is provided from
the main component to each of the branch arteries (See FIG. 20).
The extensions 452 are placed so that there is at least a 2 cm of
overlap with both the branch artery and a particular limb of the
main component. If this is not feasible using one extension,
additional extensions are added, starting distally. Another
injection of contrast through the brachial sheath confirms
positioning and sealing.
[0087] It is recognized that the extensions 452 as well as any
other component being joined, can be implanted taking either an
inferior or a superior approach. That is, the extensions can be
implanted from below the main component 350 or from above as
described. Additionally, extender cuffs can be employed to seal a
terminal end of the extension within vasculature. The extender
cuffs can take on a myriad of forms including an expandable or
self-expanding mesh-type frame defined by crossing members, or may
embody the attachment or anchoring devices 80, 90 depicted in FIGS.
2 and 3. A simple expandable elastic tube or sleeve or equivalent
structures are also suitable.
[0088] Finally, a similar procedure is used to advanced, deploy and
implant inferior extension components 601, 602, 604 (FIGS. 21, 22)
through apertures 370, 371, 372 formed in the other limbs 364, 365,
366 of the main component 350. Such inferior extension components
500, 502, 604 can be tubular or bifurcated depending on the target
anatomy and can further include the supporting, anchoring,
grappling and mating structures previously described. External
structures provide necessary friction for sealing and securing a
particular component, although a combination of internal support
and anchoring devices are satisfactory as well. Should inferior end
extensions not be required, the inferior end portions 354 of the
main component 300 can be configured with an anchoring device for
direct attachment to the aorta. When completely implanted at the
target site, blood flows through the graft device of the present
invention which operates to exclude the diseased portion being
treated.
[0089] In the event one or more of the limbs of a graft device are
not needed, occlusion of that limb may be desirable. In such an
instance, as shown in FIG. 23, for example, one limb can be blocked
with an occlusion device 610. Though various forms of an occlusion
device are acceptable, such as a windsock design, FIG. 23 depicts
an occlusion device 610 that embodies a closed end cuff design that
is placed within a particular limb 366. Structures causing a limb
to radially contract can also be employed and an elastic band can
be used for such a purpose. Of course, any such limb or other
portion of the graft device similarly occluded or can be closed
shut by suturing prior to use.
[0090] It will be apparent from the foregoing that, while
particular forms of the invention have been illustrated and
described, various modifications can be made without departing from
the spirit and scope of the invention. Accordingly, it is not
intended that the invention be limited, except as by the appended
claims.
* * * * *