U.S. patent application number 12/958383 was filed with the patent office on 2011-06-02 for modular endograft devices and associated systems and methods.
This patent application is currently assigned to Altura Medical, Inc.. Invention is credited to Andrew H. Cragg, John Fulkerson, John Logan, Isa Rizk, Stephen Sosnowski.
Application Number | 20110130826 12/958383 |
Document ID | / |
Family ID | 44069447 |
Filed Date | 2011-06-02 |
United States Patent
Application |
20110130826 |
Kind Code |
A1 |
Cragg; Andrew H. ; et
al. |
June 2, 2011 |
MODULAR ENDOGRAFT DEVICES AND ASSOCIATED SYSTEMS AND METHODS
Abstract
Modular endograft devices and associated systems and methods are
disclosed herein. In several embodiments, an endograft system can
include a first endograft device and a second endograft device that
each include an integrated frame, a cover and a lumen within the
cover. Each endograft device further includes a superior portion
and an inferior portion. The superior portion can have a convexly
curved outer wall and a septal wall. The first and second endograft
devices can be configured to extend into a low-profile
configuration with a first cross-sectional dimension and a first
length and self-expand into an expanded configuration with a second
cross-sectional dimension greater than the first cross-sectional
dimension and a second length less than the first length. In the
expanded configuration, the septal walls can press against each
other and form a septum between the lumens of the first and second
endograft devices.
Inventors: |
Cragg; Andrew H.; (Edina,
MN) ; Sosnowski; Stephen; (Vista, CA) ; Rizk;
Isa; (San Diego, CA) ; Fulkerson; John;
(Rancho Santa Margarita, CA) ; Logan; John;
(Plymouth, MN) |
Assignee: |
Altura Medical, Inc.
San Clemente
CA
|
Family ID: |
44069447 |
Appl. No.: |
12/958383 |
Filed: |
December 1, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61265713 |
Dec 1, 2009 |
|
|
|
61293581 |
Jan 8, 2010 |
|
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Current U.S.
Class: |
623/1.15 |
Current CPC
Class: |
A61F 2002/072 20130101;
A61F 2250/0039 20130101; A61F 2/89 20130101; A61F 2/90 20130101;
A61F 2/95 20130101; A61F 2002/067 20130101; A61F 2002/061 20130101;
A61F 2002/8486 20130101; A61F 2/07 20130101; A61F 2230/0034
20130101 |
Class at
Publication: |
623/1.15 |
International
Class: |
A61F 2/82 20060101
A61F002/82 |
Claims
1. A modular endograft system, comprising: a cuff having a proximal
end portion and a distal end portion; a first endograft device
having a first superior portion, a first inferior portion, and a
first lumen through the first superior and inferior portions,
wherein the first superior portion has a first outer wall and a
first septal wall; a second endograft device having a second
superior portion, a second inferior portion, and a second lumen
through the second superior and inferior portions, wherein the
second superior portion has a second outer wall and a second septal
wall; and wherein the first and second endograft devices are
configured such that the first and second outer walls of the first
and second endograft devices press against the cuff and the first
and second septal walls exert opposing forces toward one another to
fix the cuff to the first and second lumens.
2. The modular endograft system of claim 1 wherein the cuff has a
substantially circular cross section and at least one of the
proximal and distal end portions of the cuff is flared radially
outward.
3. The modular endograft system of claim 1 wherein the cuff
includes a cuff frame having a proximal terminus and a distal
terminus and a sleeve radially inward from the cuff frame, wherein
the sleeve extends over the proximal and distal termini of the cuff
frame.
4. The modular endograft system of claim 1 wherein: the cuff
includes a sleeve and a cuff frame at least partially enclosing the
sleeve; the sleeve bifurcates the cuff into a first cuff lumen and
a second cuff lumen; and the first superior portion of the first
endograft device contacts the first cuff lumen and the second
superior portion of the second endograft device contacts the second
cuff lumen.
5. The modular endograft system of claim 1 wherein the first and
second superior portions of the first and second endograft devices,
respectively, project distally beyond the distal end portion of the
cuff such that portions of the first and second outer walls of the
endograft devices affix to an adjacent vessel wall.
6. The modular endograft system of claim 1 wherein: the first
superior portion of the first endograft device includes a convexly
curved first outer wall having a first radius and a convexly curved
first septal wall having a second radius greater than the first
radius such that the first superior portion has a D-like
cross-section; the second superior portion of the second endograft
device includes a convexly curved second outer wall having the
first radius and a convexly curved second septal wall having the
second radius such that the second superior portion has a D-like
cross-section; wherein the first and second outer walls press
against the cuff device in an expanded configuration; and the first
and second septal walls press against each other in the expanded
configuration and form a septum, and the convex curvature of the
first and second septal walls results in a substantially uniform
distribution of pressure along the septum.
7. The modular endograft system of claim 6 wherein: the first
septal wall and the first outer wall are joined at curved corners;
the second septal wall and the second outer wall are joined at
curved corners; and the curved corners have a radius of curvature
less than the first radius, and wherein the curved corners form an
angle from approximately 60.degree. to approximately 100.degree. at
the septum in the expanded configuration.
8. The modular endograft system of claim 1, further comprising at
least one anchor coupled to an exterior of the cuff, wherein the
anchor protrudes radially from the cuff in an expanded
configuration and constricts in a low-profile configuration.
9. The modular endograft system of claim 1 wherein the first and
second endograft devices include at least one anchor at the first
and second superior portions, wherein the anchor protrudes radially
from the superior portions in an expanded configuration.
10. The modular endograft system of claim 1 wherein: the first
endograft device includes a first alignment aid at the first septal
wall; and the second endograft device includes a second alignment
aid at the second septal wall, wherein the second alignment aid
crosses the first alignment aid when the first and second septal
walls of the first and second endograft devices, respectively,
oppose one another such the first and second septal walls form a
septum.
11. The modular endograft system of claim 1 wherein: the cuff
includes a first cuff alignment aid and a second cuff alignment
aid; the first endograft device includes a first alignment aid at
the first outer wall, wherein the first alignment aid crosses the
first cuff alignment aid when the first outer wall opposes the
cuff; and the second endograft device includes a second alignment
aid at the second outer wall, wherein the second alignment aid
crosses the second cuff alignment aid when the second outer wall
opposes the cuff.
12. The modular endograft system of claim 1 wherein: the first
endograft device further includes a first transition portion
between the first superior portion and the first inferior portion,
the first transition portion tapering the first lumen from a first
cross-sectional dimension at the superior portion to a second
cross-sectional dimension less than the first cross-sectional
dimension at the inferior portion, wherein the transitional portion
is configured to maintain substantially laminar blood flow through
the first lumen in an expanded configuration; the second endograft
device further includes a second transition portion between the
second superior portion and the second inferior portion, the second
transition portion tapering the second lumen from the first
cross-sectional dimension at the second superior portion to the
second cross-sectional dimension at the second inferior portion,
wherein the second transitional portion is configured to maintain
substantially laminar blood flow through the second lumen in the
expanded configuration; and the cuff further includes a
transitional cuff portion at the proximate end portion, the tapered
cuff portion being substantially conformal to the first and second
tapered transitional portions.
13. The modular endograft system of claim 1 wherein the first and
second endograft devices each include a frame having a superior
terminus, an inferior terminus, and a continuous wire woven in a
braid, the wire crossing itself at a braid angle, and the wire
reversing direction at the superior terminus of the frame to form a
first plurality of loops and reversing direction at the inferior
terminus of the frame to form a second plurality of loops.
14. The modular endograft system of claim 13 wherein the first and
second endograft devices each further include a cover over at least
a portion of the frame, the cover having circumferential ribs
protruding radially from the frame such that opposing
circumferential ribs of the first and second septal walls mate in
the expanded configuration.
15. A modular endograft system, comprising: a cuff having a cuff
frame and a sleeve attached to the cuff frame, wherein the cuff
frame and the sleeve have a proximal end portion and a distal end
portion; a first endograft device having a first frame, a first
cover attached to the first frame, and a first lumen within the
first cover, wherein the first frame and the first cover have a
first superior portion and a first inferior portion, and the first
superior portion has a convexly curved first outer wall and a first
septal wall; a second endograft device having an integrated second
frame ("second frame"), a second cover attached to the second
frame, and a second lumen within the second cover, wherein the
second frame and the second cover have a second superior portion
and a second inferior portion, the second superior portion having a
convexly curved second outer wall and a second septal wall; and
wherein the first and second endograft devices are configured to be
extended into a low-profile configuration with a first
cross-sectional dimension and expand to an expanded profile
configuration with a second cross-sectional dimension greater than
the first cross-sectional dimension such that in the expanded
configuration the first and second septal walls are urged toward
each other and form a septum between the first and second lumens
and the first and second outer walls press against an interior of
the cuff.
16. The modular endograft system of claim 15 wherein at least one
of the proximal and distal end portions of the cuff frame is flared
radially outward.
17. The modular endograft system of claim 16 wherein the sleeve
extends over proximal and distal ends of the cuff frame such that
the sleeve attaches to the cuff frame when the cuff presses against
vessel walls.
18. The modular endograft system of claim 15 wherein the sleeve
includes a first cuff lumen configured to receive the first
endograft device and a second cuff lumen configured to receive the
second endograft device.
19. The modular endograft system of claim 15 wherein the first and
second endograft devices are staggered longitudinally relative to
the first and second lumens such that the first superior portion
includes a free end portion projecting distally beyond the second
superior portion of the second endograft device.
20. The modular endograft system of claim 15 wherein the first and
second frames each include a superior terminus, an inferior
terminus, and a continuous wire woven in a braid, the wire crossing
itself at a braid angle, and the wire reversing direction at the
superior terminus to form a first plurality of loops and reversing
direction at the inferior terminus to form a second plurality of
loops
21. The modular endograft system of claim 20 wherein the braid
angle is from approximately 30.degree. to approximately
45.degree..
22. The modular endograft system of claim 20 wherein the wire has a
diameter from approximately 0.0070 inch to approximately 0.0140
inch and the first plurality of loops includes no more than eight
loops and the second plurality of loops includes no more than eight
loops.
23. The modular endograft system of claim 15 wherein the first and
second covers extend over the first and second frames, and wherein
the first and second covers limit at least one of radial expansion
and longitudinal contraction of the first and second frames,
respectively, in the expanded configuration.
24. The modular endograft system of claim 15 wherein: at least a
portion of the sleeve is radially inward from the cuff frame, and
wherein the sleeve includes ribs protruding radially inward from
the cuff frame; the first cover includes first ribs protruding
radially from the first frame in the dilated configuration, the
first ribs being extendable longitudinally in the low-profile
configuration; the second cover includes second ribs protruding
radially from the second frame in the dilated configuration, the
second ribs being extendable longitudinally in the low-profile
configuration; and wherein the first and second ribs interface with
the ribs of the sleeve in the expanded configuration.
25. The modular endograft system of claim 15, further comprising at
least one anchor protruding radially outward from an exterior of
the cuff.
26. The modular endograft system of claim 15 wherein the first and
second superior portions include alignment aids on opposing first
and second septal walls, the alignment aids being configured to
cross one another when the first and second septal walls form the
septum.
27. A method of repairing an aneurysm in a primary blood vessel
before a bifurcation into a first blood vessel and a second blood
vessel, comprising: advancing a cuff through the first blood vessel
to a target site in the primary blood vessel before the aneurysm,
the cuff having a substantially circular cross-section; deploying
the cuff at the target site such that the cuff presses against a
vessel wall of the primary blood vessel; advancing a first
endograft device through the first blood vessel to a target site in
the common blood vessel before the aneurysm; advancing a second
endograft device through the second blood vessel to the target
site; deploying the first and second endograft devices at the
target site such that the first and second endograft devices expand
to an expanded configuration via inherent spring forces in the
first and second endograft devices such that first and second
septal walls of the first and second endograft devices,
respectively, press toward each other and form a septum between the
first and second endograft devices, and wherein first and second
outer walls of the first and second endograft devices,
respectively, sealably press against an interior surface of the
cuff; and wherein the first and second endograft devices are
positioned independently of one another.
28. The method of claim 27 wherein positioning the first and second
endograft devices independently comprises: positioning a first
superior portion of the first endograft device in a first desired
position within the cuff; and positioning a second superior portion
of the second endograft device in a second desired position within
the cuff, wherein the first desired position is longitudinally
offset from the second desired position along the cuff.
29. The method of claim 27, further comprising: loading the first
endograft device in a first catheter, wherein the first endograft
device is extended in a low-profile configuration; loading the
second endograft device in a second catheter, wherein the second
endograft device is extended in a low-profile configuration;
percutaneously introducing the first endograft device into the
first blood vessel; and percutaneously introducing the second
endograft device into the second blood vessel.
30. The method of claim 29 wherein the first and second endograft
devices have a cross-sectional dimension no less than 20 mm in the
dilated configuration, and wherein the first and second catheters
are no larger than 12 F.
31. The method of claim 27 wherein the first endograft device
includes a first alignment aid at the first septal wall and the
second endograft device includes a second alignment aid at the
second septal wall, the first and second alignment aids comprising
a radiopaque material, and wherein deploying the first and second
endograft devices further includes: radiographically positioning
the first and second alignment aids such that the first and second
alignment aids oppose one another; viewing the first and second
alignment aids in the orthogonal plane; and crossing the first and
second alignment aids such that the first and second septal walls
can form the septum.
32. The method of claim 31 wherein the first and second alignment
aids diagonally cross the first and second septal walls, and
wherein the first and second alignment aids form an "X" indicator
at the septum.
33. The method of claim 27 wherein the cuff includes a cuff frame
and an internal sleeve having ribs protruding radially inward from
the cuff frame, the first and second endograft devices each include
a cover having a plurality of circumferential ribs at least at the
first and second septal and outer walls of the first and second
endograft devices, respectively, and wherein deploying the first
and second endograft devices further comprises: interfacing the
circumferential ribs at the first septal wall with the
circumferential ribs at the second septal wall; and interfacing the
circumferential ribs at the first and second outer walls with the
ribs of the internal sleeve.
34. The method of claim 27 wherein the first and second endograft
devices each include a cover attached over at least a portion of a
frame, and deploying the first and second endograft devices further
comprises restricting radial expansion of the frames with the
covers.
35. The method of claim 27 wherein the primary blood vessel is an
aorta and the first blood vessel is a first common iliac artery and
the second blood vessel is a second common iliac artery, and
wherein deploying the cuff and the first and second endograft
devices further includes: at least substantially sealing the cuff
with an arterial wall of the aorta; at least substantially sealing
the first inferior portion with an interior arterial wall of the
first common iliac artery; and at least substantially sealing the
second inferior portion with an interior arterial wall of the
second common iliac artery.
36. The method of claim 27 wherein the primary blood vessel
includes a third blood vessel and a fourth blood vessel branching
from the primary blood vessel before the aneurysm, the third and
fourth blood vessels being longitudinally offset from one another
relative to the primary blood vessel, and wherein: the first
endograft device has a first braided frame and a first cover
coupled to the first braided frame, the first cover having a first
inferior terminus and a first superior terminus, and the first
braided frame having a first end extending distally beyond the
first superior terminus of the first cover and second end extending
proximally beyond the first inferior terminus of the first cover,
wherein the first and second end portions include openings through
which blood can flow laterally relative to a longitudinal axis of
the first lumen; the second endograft device has a second braided
frame and a second cover attached to the second braided frame, the
second cover having a second inferior terminus and a second
superior terminus, and the second braided frame having a first end
extending distally beyond the second superior terminus of the
second cover and a second end extending proximally beyond the
second inferior terminus of the second cover, wherein the first and
second end portions include openings through which blood can flow
laterally relative to a longitudinal axis of the second lumen;
deploying the cuff comprises positioning the cuff proximal to the
third and fourth blood vessels; and deploying the first and second
endograft devices comprises positioning the first end portion of
the first frame at the entrance of the third blood vessel and
positioning the first end portion of the second frame at the
entrance of the fourth blood vessel such that the third and fourth
blood vessels are in fluid communication with blood flow through
the first and the second lumens.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to each of the
following U.S. Provisional Applications:
[0002] (A) U.S. Provisional Application No. 61/265,713, filed on
Dec. 1, 2009, entitled "IMPROVED SYSTEMS AND METHODS FOR MODULAR
ABDOMINAL AORTIC ANEURYSM GRAFT;" and
[0003] (B) U.S. Provisional Application No. 61/293,581, filed Jan.
11, 2010, entitled "IMPROVED SYSTEMS AND METHODS FOR MODULAR
ABDOMINAL AORTIC ANEURYSM GRAFT."
[0004] All of the foregoing applications are incorporated herein by
reference in their entireties.
TECHNICAL FIELD
[0005] The present technology generally relates to endograft
devices and methods for percutaneous endovascular delivery of the
endograft devices across aneurysms. In particular, several
embodiments are directed toward a modular bi-luminal endograft
device with independently positioned components for endovascular
aneurysm repair.
BACKGROUND
[0006] An aneurysm is a dilation of a blood vessel at least 1.5
times above its normal diameter. The dilated vessel can form a
bulge known as an aneurysmal sac that can weaken vessel walls and
eventually rupture. Aneurysms are most common in the arteries at
the base of the brain (i.e., the Circle of Willis) and in the
largest artery in the human body, the aorta. The abdominal aorta,
spanning from the diaphragm to the aortoiliac bifurcation, is the
most common site for aortic aneurysms. The frequency of abdominal
aortic aneurysms ("AAAs") results at least in part from decreased
levels of elastins in the arterial walls of the abdominal aorta and
increased pressure due to limited transverse blood flow.
[0007] Aneurysms are often repaired using open surgical procedures.
Surgical methods for repairing AAAs, for example, require opening
the abdominal region from the breast bone to the pelvic bone,
clamping the aorta to control bleeding, dissecting the aorta to
remove the aneurysmal section, and attaching a prosthetic graft to
replace the diseased artery. The risks related to general
anesthesia, bleeding, and infection in these types of open surgical
repairs result in a high possibility of operative mortality. Thus,
surgical repair is not a viable option for many patients. Moreover,
the recovery process is extensive for the patients fit for surgical
repair. An open surgical repair of an AAA generally requires seven
days of post-operational hospitalization and, for uncomplicated
operations, at least six to eight weeks of recovery time. Thus, it
is a highly invasive and expensive procedure.
[0008] Minimally invasive surgical techniques that implant
prosthetic grafts across aneurysmal regions of the aorta have been
developed as an alternative or improvement to open surgery.
Endovascular aortic repairs ("EVAR"), for example, generally
require accessing an artery (e.g., the femoral artery)
percutaneously or through surgical cut down, introducing guidewires
into the artery, loading an endograft device into a catheter, and
inserting the loaded catheter in the artery. With the aid of
imaging systems (e.g., X-rays), the endograft device can be guided
through the arteries and deployed from a distal opening of the
catheter at a position superior to the aneurysm. From there, the
endograft device can be deployed across the aneurysm such that
blood flows through the endograft device and bypasses the
aneurysm.
[0009] EVAR devices should be implanted at a precise location
across the aneurysmal region and securely fixed to the vessel wall
because improper placement, migration, and/or projection of the
endograft device into branching vessels may interfere with the
blood flow to nearby physiological structures. For example, to
avoid impairing renal functions, the endograft device should not
inhibit blood flow to the renal arteries. In addition to the
variations in the vasculature between patients, the characteristics
of the aneurysms themselves can also pose challenges because of the
anatomical variations and the different structural features of
individual aneurysms. For example, the vascular bifurcation at the
iliac arteries and the angulation of aneurysmal sacs are both known
to pose challenges to methods and devices for treating AAAs.
Conventional systems address these challenges by having many
different EVAR devices with different sizes and shapes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1A is a partial cut-away, isometric view of a modular
endograft system configured in accordance with an embodiment of the
technology.
[0011] FIG. 1B is an isometric view of the modular endograft system
of FIG. 1A configured in accordance with an embodiment of the
technology.
[0012] FIGS. 2A-C are cross-sectional top views of superior
portions for endograft devices shaped in accordance with
embodiments of the technology.
[0013] FIGS. 2D and 2E are cross-sectional top views of the
superior portion of FIG. 2B being mated with a complementary
superior portion in accordance with an embodiment of the
technology.
[0014] FIGS. 3A and 3B are isometric views of endograft devices
configured in accordance with embodiments of the technology.
[0015] FIGS. 4A and 4B are side views of an integrated frame in an
expanded configuration and in a low-profile configuration,
respectively, in accordance with an embodiment of the
technology.
[0016] FIGS. 5A-C are side views of a cover being extended from an
expanded configuration to a low-profile configuration in accordance
with an embodiment of the technology.
[0017] FIGS. 6A and 6B are cross-sectional views of an endograft
device in a low-profile configuration and in an expanded
configuration, respectively, in accordance with embodiments of the
technology.
[0018] FIGS. 7A and 7B are isometric views of endograft devices
configured in accordance with other embodiments of the
technology.
[0019] FIGS. 8A and 8B are isometric views of endograft devices
configured in accordance with further embodiments of the
technology.
[0020] FIGS. 9A and 9B are schematic views of a two-part modular
endograft system being deployed across an aneurysm in accordance
with an embodiment of the technology.
[0021] FIGS. 10A and 10B are isometric views of modular endograft
systems configured in accordance with additional embodiments of the
technology.
[0022] FIGS. 11A and 11B are schematic views of the modular
endograft system of FIG. 10A and the modular endograft system of
FIG. 10B, respectively, deployed across aneurysms in accordance
with other embodiments of the technology.
[0023] FIG. 12 is a schematic view of the modular endograft system
of FIG. 9B deployed across an aneurysm in accordance with a further
embodiment of the technology.
[0024] FIGS. 13A-C are schematic views of a four-part modular
endograft system being deployed across an aneurysm in accordance
with an embodiment of the technology.
[0025] FIGS. 14A and 14B are isometric views of a modular endograft
system configured in accordance with an additional embodiment of
the technology.
[0026] FIGS. 15A and 15B are schematic views of a three-part
modular endograft system being deployed across an aneurysm in
accordance with an embodiment of the technology.
[0027] FIG. 16 is a schematic view of a five-part modular endograft
system being deployed across an aneurysm in accordance with an
embodiment of the technology.
[0028] FIGS. 17A-E are views of coating layers being applied to an
integrated frame in accordance with an embodiment of the
technology.
DETAILED DESCRIPTION
[0029] Specific details of several embodiments of the technology
are described below with reference to FIGS. 1A-17E. Although many
of the embodiments are described below with respect to devices that
at least partially repair abdominal aortic aneurysms ("AAAs"),
other applications and other embodiments are within the scope of
the technology. For example, the technology can be used to repair
aneurysms in other portions of the vasculature. Additionally,
several other embodiments of the technology can have different
configurations, components, or procedures than those described in
this section. A person of ordinary skill in the art, therefore,
will accordingly understand that the technology may have other
embodiments with additional elements, or the technology may have
other embodiments without several of the features shown and
described below with reference to FIGS. 1A-17E.
[0030] With regard the use of "superior" and "inferior" within this
application, inferior generally refers being situated below or
directed downward, and superior generally refers to being situated
above or directed upward.
[0031] With regard to the use of "expansion" and "constriction"
within this application, expansion refers to a radial increase in a
cross-sectional dimension of a device or component, and
constriction refers to a radial decrease in the cross-sectional
dimension of the device or component. For example, FIG. 4A shows an
integrated frame 104 in an expanded configuration, and FIG. 4B
shows the integrated frame 104 in a constricted configuration.
[0032] With regard to the use of "contraction" and "extension"
within this application, contraction refers to a longitudinal
decrease in the length of a device or component, and extension
refers to a longitudinal increase in the length of the device or
component. For example, FIG. 5A shows a cover 106 in a contracted
configuration, and FIG. 5C shows the cover 106 in an extended
configuration.
[0033] With regard to the terms "distal" and "proximal" within this
application, the terms can reference a relative position of the
portions of an implantable device and/or a delivery device with
reference to an operator. Proximal refers to a position closer to
the operator of the device, and distal refers to a position that is
more distant from the operator of the device.
[0034] 1. Endograft System Structures
[0035] 1.1 Selected Endograft Devices
[0036] FIGS. 1A and 1B are isometric views of a modular endograft
system 100 ("system 100") in accordance with an embodiment of the
technology. The system 100 can include separate endograft devices
102 (identified individually as a first endograft device 102a and a
second endograft device 102b) that can be coupled, mated, or
otherwise substantially sealed together in situ. Each endograft
device 102, for example, can include an integrated frame 104
("frame 104") and a substantially impermeable cover 106 ("cover
106") extending over at least a portion of the frame 104. The frame
104 and the cover 106 of an individual endograft device 102 can
form a discrete lumen 116 through which blood can flow to bypass an
aneurysm. In operation, the endograft devices 102 are generally
delivered separately and positioned independently across the
aneurysm.
[0037] As shown in FIGS. 1A and 1B, each endograft device 102
includes a superior portion 108 and an inferior portion 110. The
superior portion 108 can include a convexly curved outer wall 112
and a septal wall 114. As shown in FIG. 1A, the septal wall 114 can
be substantially flat such that the superior portion 108 forms a
"D" shape at a superior portion of the lumen 116. In other
embodiments, the septal wall 114 can be convexly curved with a
larger radius of curvature than the outer wall 112 such that the
superior portion 108 forms a complex ellipsoid having another
D-shaped cross-section at the superior portion of the lumen 116. In
further embodiments, the superior portion 108 can have asymmetrical
shapes or other suitable cross-sectional configurations that can
mate with each other in the septal region and mate with an arterial
wall around the periphery of the outer wall 112. The inferior
portion 110 can have a circular cross-sectional shape as
illustrated in FIG. 1A, or the inferior portion 110 can have an
elliptical shape, a rectangular shape, an asymmetrical shape,
and/or another suitable cross-sectional shape for an inferior
portion of the lumen 116.
[0038] The superior portions 108 of the endograft devices 102 are
mated together and at least substantially sealed along the septal
walls 114 within the aorta above the aneurysm. In some embodiments,
the superior portion 108 can be approximately 2-4 cm in length to
adequately fix the outer walls 112 to the arterial walls such that
they are at least substantially sealed together. In other
embodiments, the superior portion 108 can be longer or shorter. In
one embodiment in accordance with the technology, the inferior
portions 110 can extend through an inferior portion of the aneurysm
and into corresponding iliac arteries to bypass the aneurysm. In
another embodiment, one or both inferior portions 110 can terminate
within the aneurysm to form what is known to those skilled in the
art as a "gate." As described in further detail below, limbs (not
shown) can be attached to the proximal ends of the inferior
portions 110 and extended into the iliac arteries to bypass the
aneurysm.
[0039] In the embodiment shown in FIGS. 1A and 1B, the frames 104
have bare end portions 118 (identified individually as first end
portions 118a and second end portions 118b) that extend beyond the
covers 106. As shown in FIGS. 1A and 1B, the first end portion 118a
can extend distally from the superior terminus of the cover 106,
and the second end portion 118b can extend proximally from the
inferior terminus of the cover 106. In some embodiments, the end
portions 118 can be trumpeted or flared to interface with the
arterial walls of the aorta and/or the iliac arteries. This can
promote cell ingrowth that strengthens the seal between the
endograft devices 102 and the adjacent arteries.
[0040] The end portions 118 can also increase the available
structure for securing the endograft device 102 to the artery and
increase the surface area of the covers 106 for sealably fixing the
endograft devices 102 to arterial walls. This decreases the
precision necessary to position the endograft devices 102 and
increases the reliability of the implanted system 100. For example,
a short infrarenal aortic neck (e.g., less than 2 cm) generally
requires precise placement of the endograft devices 102 to preserve
blood flow to the renal arteries while still providing enough
surface area for the endograft devices 102 to be properly affixed
with the aorta. In the embodiment shown in FIGS. 1A and 1B,
however, the first end portions 118a can be placed at the entrance
of the renal arteries to allow lateral blood flow into the renal
arteries and provide a larger structure for fixing the endograft
devices 102 to the arterial wall and a larger sealing area with the
arterial wall. The end portions 118 can also provide accessible
sites for recapture (e.g., by guidewires, bead and collet, etc.)
that enhance the accuracy of positioning the endograft devices 102
across the aneurysm.
[0041] During deployment of the system 100, each endograft device
102 can be delivered independently to an aneurysmal region in a
low-profile configuration. The low-profile configuration has a
first cross-sectional dimension and a first length that can
facilitate percutaneous endovascular delivery of the system 100.
Because each device 102 extends around only a portion of the vessel
periphery, the individual endograft devices 102 can be constricted
(i.e., radially collapsed) to a smaller diameter than conventional
AAA devices with a single superior portion that extends around the
complete periphery of the vessel wall. In some embodiments, for
example, each of the endograft devices 102 can have a diameter of
25 mm in the expanded configuration, and can be constricted to a
diameter of 4 mm in the low-profile configuration to be
percutaneously deployed across the aneurysm through a 12 F
catheter. Additionally, as described in more detail below, because
each endograft device 102 is delivered independently, the end
portions 118 and fenestrations can facilitate staggering the
endograft devices 102 to accommodate asymmetrical anatomies.
[0042] At a target site in the aneurysmal region, the endograft
devices 102 can self-expand to an expanded configuration (e.g.,
shown in FIGS. 1A and 1B). The expanded configuration can have a
second cross-sectional dimension greater than the first
cross-sectional dimension and a second length less than the first
length. In the expanded configuration shown in FIG. 1B, the septal
wall 114 (FIG. 1A) of the first endograft device 102a can be forced
against the opposing septal wall 114 of the second endograft device
102b. When in situ within the aorta, the forces between the
opposing septal walls 114 form a septum 120 in which the first and
second septal walls 114 are at least substantially sealed together
to prevent blood from flowing between the endograft devices 102 and
into the aneurysm. Additionally, as shown in FIG. 1B, the texture
(e.g., ribbing) on the covers 106 can mate at the septum 120 to
further strengthen the seal between the septal walls 114.
Similarly, the texture of the cover 106 on the outer walls 112 can
interface with the adjacent vessel walls to strengthen the seal
around the periphery of the endograft devices 102.
[0043] In operation, the system 100 can prevent blood from
collecting in a diseased aneurysmal portion of a blood vessel
(e.g., the aorta, the iliac arteries, etc.). Rather, the system 100
can direct blood into the lumens 116, funnel the blood through the
superior and inferior portions 108 and 110, and discharge the blood
into healthy portions of the iliac arteries, thereby at least
substantially bypassing the aneurysm. The bifurcated system 100
facilitates independent positioning of the first and second
endograft devices 102 to accommodate disparate structures and
morphologies of the abdominal aorta and/or iliac arteries. For
example, the first endograft device 102a can be positioned
independently in a desired location without being constrained by a
desired placement of the second endograft device 102b. Accordingly,
the system 100 can easily adapt to a variety of different anatomies
and thereby provide a modular alternative to customized endograft
systems.
[0044] 1.2 Select Embodiments of Superior Portions
[0045] FIGS. 2A-C are cross-sectional top views of superior
portions 208 of endograft devices (e.g., endograft devices 102
shown in FIGS. 1A and 1B) shaped in accordance with embodiments of
the technology. The superior portions 208 can have generally
similar features as the superior portions 108 shown in FIGS. 1A and
1B. For example, each superior portion 208 includes an outer wall
212 and a septal wall 214. The outer wall 212 is generally
semi-circular, but can otherwise be configured according to the
shape, geometry, and/or morphology of an arterial wall. The septal
wall 214 can be shaped to mate with a complementary septal wall 214
of another endograft device. More specifically, in the embodiment
illustrated in FIG. 2A, the superior portion 208 includes a
convexly curved, substantially semi-circular outer wall 212 and a
substantially flat septal wall 214. Thus, the superior portion 208
forms a "D" shape and can be part of a system (e.g., the system 100
shown in FIGS. 1A and 1B) including a corresponding D-shaped
superior portion of a mating endograft device.
[0046] In other embodiments, both the outer wall 212 and the septal
wall 214 can be convexly curved such that the superior portion 208
forms a complex ellipsoid with at least two distinct radii. FIG.
2B, for example, shows the superior portion 208 can include a
convexly curved outer wall 212 that has a first radius R1 and a
convexly curved septal wall 214 that has a second radius R2 greater
than the first radius R1. In the embodiment illustrated in FIG. 2B,
the second radius R2 is substantially greater than the first radius
R1 such that the superior portion 208 has a substantially D-like
shape.
[0047] Similarly, the superior portion 208 shown in FIG. 2C
includes the convexly curved outer wall 212 that has the first
radius of curvature R1 and the convexly curved septal wall 214 that
has the second radius of curvature R2 greater than the first radius
R1. As shown in FIG. 2C, the superior portion 208 can further
include convexly curved corner sections 222 (identified
individually as a first corner section 222a and a second corner
section 222b). The first corner section 222a can have a third
radius R3, and the second corner section 222b can have a fourth
radius R4 distinct from or equivalent to the third radius R3. In
the embodiment shown in FIG. 2C, the third and fourth radii R3 and
R4 are substantially smaller than the first and second radii R1 and
R2 such that the superior portion 208 forms another substantially
D-like shape. In other embodiments, the superior portion 208 can
include greater or smaller radii, more or less curved portions,
and/or can have another shape suitable for mating and at least
substantially sealing two endograft devices together within a blood
vessel.
[0048] FIGS. 2D and 2E are cross-sectional top views of the
superior portion 208 of FIG. 2B being mated with a complementary
superior portion 208 to form a sealed septum 220 in accordance with
an embodiment of the technology. More specifically, FIG. 2D shows
the superior portions 208 being pressed toward one another by a
force F. The force F can derive from the self-expansion of the
superior portions 208 within the confined space of an aorta. As
shown in FIG. 2D, the force F can cause the superior portions 208
to contact one another near the center of their respective convexly
curved septal walls 214 and flatten the septal walls 214. The
apposition of the septal walls 214 can generate an outward force
generally tangential to the septal walls 214 that can cause a
slight outward bowing B near the interface of the outer and septal
walls 212 and 214.
[0049] As shown in FIG. 2E, the force F can continue to press the
superior portions 208 against one another until the convexly curved
septal walls 214 straighten to form the septum 220. The initial
convexities of the septal walls 214 can induce more pressure
between the septal walls 214 than straight septal walls (e.g., FIG.
2A) and promote an even distribution of the force along the septum
220 to enhance the seal. Additionally, the outward bowing B can
enhance the seal at the edges of the septal walls 214. The superior
portions 208 shown in FIGS. 2A and 2C can be similarly joined to
form the substantially straight septum 220. For example, the
superior portion 208 shown in FIG. 2C can be pressed against a
corresponding superior portion such that the relative forces
between the superior portions 208 substantially straighten the
septal walls 214 and corner sections 222 (e.g., approximately
60.degree. to 90.degree. between the outer and septal walls 112 and
114) to form the septum 220. In operation, the septum 220 can be at
least substantially sealed to prevent fluids (e.g., blood) from
flowing between the superior portions 208.
[0050] 1.3 Select Embodiments of Transition Portions
[0051] FIGS. 3A and 3B are isometric views of transition portions
324 of endograft devices configured in accordance with embodiments
of the technology. The transition portions 324 can promote laminar
blood flow by gradually changing the size of the lumen 116 from the
wider, superior portion 108 to the narrower, inferior portion 110.
Additionally, the transition portions 324 can be configured to
reduce the downforce exerted on the endograft devices 102 as blood
flows through the lumen 116.
[0052] More specifically, FIG. 3A is an isometric view of the
endograft device 102 described above with reference to FIGS. 1A and
1B. The endograft device 102 includes the transition portion 324
positioned between the superior portion 108 and the inferior
portion 110. As shown in FIG. 3A, the transition portion 324 can be
tapered to gradually narrow the cross-section of the lumen 116 and
thereby reduce disruptions to the blood flow. The transition
portion 324 can have a length L related to the distance necessary
to continue substantially laminar blood flow through the lumen 116.
For example, in some embodiments, the length L can be 4 cm. In
other embodiments, the length L can differ due to the geometry of
the endograft device 102, the rheologic characteristics of the
blood flow, and/or other relevant factors in decreasing turbulent
blood flow. In other embodiments, the transition portion 324 can be
sloped, stepped, and/or have another suitable shape that can
decrease the cross-section of the lumen 116 from the superior
portion 108 to the inferior portion 110 without inducing turbulent
blood flow.
[0053] FIG. 3B is an isometric view of an endograft device 302 in
accordance with another embodiment of the technology. The endograft
device 302 can include generally similar features as the endograft
102 shown in FIG. 3A. However, the tapered transition portion 324
shown in FIG. 3B has a more gradual taper and a much greater length
L than the transition portion 324 shown in FIG. 3A. As shown in
FIG. 3B, the tapered transition portion 324 extends from the
superior portion 108 to the second end portion 118b such that the
transition portion 324 defines the inferior portion 110 (not
visible). Accordingly, the tapered transition portion 324 can
steadily decrease the cross-section of the lumen 116 to facilitate
laminar blood flow through the lumen 116. The gradual taper of the
transition portion 324 may, however, cause the endograft device 302
to migrate in the direction of blood flow more than the more
aggressive taper of the transition portion 324 shown in FIG. 3A.
Accordingly, the length L and angle of the tapered transition
portion 324 can be optimized to mitigate migration of the endograft
device 302 without inducing undo turbulent blood flow. In other
embodiments, the transition portion 324 can optimize the geometry
of a different shape (e.g., stepped) to maintain laminar blood flow
and mitigate migration of the endograft device 302.
[0054] 2. Endograft System Components
[0055] 2.1 Integrated Frames
[0056] FIGS. 4A and 4B are side views of the integrated frame 104
described with reference to FIGS. 1A and 1B in an expanded
configuration (FIG. 4A) and a low-profile configuration (FIG. 4B)
in accordance with an embodiment of the technology. As discussed
above, the frame 104 includes the superior portion 108, the
inferior portion 110, and the exposed end portions 118. In some
embodiments, the smallest radius of the outer wall 112 of each
superior portion 108 in the expanded configuration may not be less
than 10 mm (i.e., the smallest diameter of the superior portions
108 of mated endograft devices 102 is more than 20 mm).
[0057] As shown FIGS. 4A and 4B, the frame 104 can be a braided
structure made from one or more continuous, interwoven wires 426
that provide a continuous, integrated support longitudinally along
the length of the frame 104. For example, as shown in FIG. 4A, the
wire 426 is braided such that a first longitudinal segment L1 of
the frame 104 supports an adjacent second longitudinal segment L2
of the frame 104. Accordingly, each area of the frame 104
influences the radial expansion or contraction of an adjacent area
of the frame. In some embodiments, the frame 104 is woven with one
wire 426 that continuously crosses itself along the length of the
frame 104. The intersections of the wire 426 may not be welded or
otherwise fixed together such that they remain unbound to increase
the flexibility of the frame 104. In other embodiments, the frame
104 includes a plurality of wires 426 that can be interwoven and/or
concentrically layered to form the frame 104. The frame 104, for
example, can include eight wires 426 in which several of the wires
426 can end at intermediate points along the length of the frame
104. Such a staggered, multi-wire construction prevents the wire
ends from weakening the frame 104 and/or from wearing on a
subsequently attached cover (e.g., the cover 106 shown in FIGS. 1A
and 1B). The number of wires 426 can also vary at different
sections along the length of the frame 104. For example, in one
embodiment, the inferior portion 110 includes fewer wires 426 than
the superior portion 108 such that the density or pitch of the
wires 426 does not increase at inferior portion 110 and the frame
104. This enables the inferior portion 110 to have a small diameter
in the constricted, low-profile configuration (FIG. 4B).
[0058] As shown in FIG. 4A, the wires 426 can form a loop 428 at
one end portion 118 to reverse direction and continue weaving along
the length of the frame 104 toward the opposite end portion 118.
The optimal number of loops 428 at each end portion 118 can be
associated with the diameter of the wires 426. Too few loops 428
can decrease the strength at the end portions 118 of the contracted
frame 104 shown in FIG. 4A. Too many loops 428 can increase the
profile of the extended frame 424 shown in FIG. 4B, and can also
cause difficulty attaching the cover. A wire 426 with a diameter of
0.008 inch, for example, may have an optimal number of ten to
twelve loops 428 (five to six at each end portion 118), whereas a
wire 426 with a diameter of 0.009 inch may have an optimal number
of twelve to fourteen loops 428. In other embodiments, the wires
426 can include more or less loops 428 to optimize characteristics
of the frame 104. Additionally, the degree of curvature of each of
the loops 428 can impact the durability of the wires 426. For
example, tightly wound loops 428 with high degrees of curvature are
subject to fatigue and failure at the end portions 118 because of
the stress induced upon constriction. Therefore, in some
embodiments, the degree of curvature of the loops 428 can be the
least degree of curvature permissible for the optimal number of
loops 428.
[0059] In the expanded configuration shown in FIG. 4A, the wires
426 can cross at a braid angle .theta. selected to mitigate kinking
and provide adequate extension/constriction. Lower braid angles
.theta. can reduce or eliminate kinking of the wires 426 when the
frame 104 is flexed or bent. For example, a braid angle .theta. of
less than 45.degree. allows the frame 104 to bend with smaller
radii of curvature without substantial reduction of its
cross-sectional area along the length of the frame 104. Therefore,
a frame 104 with a braid angle .theta. of less than 45.degree. can
be flexed and bent within the anatomy (e.g., the aorta) without
restricting blood flow through the frame 104. Additionally, lower
braid angles .theta. can increase the outward spring force (i.e.,
the inherent force within the frame 104 that self-expands the frame
104 to the expanded configuration) and hoop strength (i.e., the
radial strength of the frame 104 that restricts kinking and
maintains the expanded configuration) of the frame 104. Therefore,
braid angles .theta. of not more than 45.degree. can also provide
an advantageous increase in the strength and corresponding
durability of the frame 104.
[0060] Lower braid angles .theta., however, can also adversely
affect the extension and constriction of the frame 104 in the
low-profile configuration shown in FIG. 4B. For example, extension
and constriction can be negatively impacted at braid angles .theta.
of less than 30.degree.. Therefore, in some embodiments, the frame
104 can include a braid angle .theta. between 30.degree. and
45.degree. that promotes kink resistance and frame strength, while
also maintaining extension and constriction abilities necessary for
the low-profile configuration. In other embodiments, the optimal
braid angle .theta. can be higher or lower.
[0061] In some embodiments in accordance with the technology, the
braid angle .theta. can vary along the length of the frame 104 to
vary kink resistance, outward spring force, hoop strength, and
extension properties at different portions of the frame 104. For
example, the braid angle .theta. can be higher at the superior
portion 108 (e.g., 40.degree.) such that the superior portion 108
can extend and constrict into the low-profile configuration, and
the braid angle .theta. can be lower at the inferior portion 110
(e.g., 30.degree.) to provide kink resistance where the frame 104
is most likely to bend (e.g., within the aneurysmal sac and toward
the iliac arteries). The smaller braid angle .theta. at the
inferior portion 110 may not adversely affect the profile of the
frame 104 because the inferior portion 110 need not constrict as
much as the superior portion 108 to reach the desired low-profile
configuration. In other embodiments, the braid angle .theta. of the
frame 104 may vary in another way.
[0062] The wires 426 can have a diameter sufficient to support the
frame 104 while still providing substantial flexibility for the
frame 104. The diameter of the wires 426 can be selected to attain
a desired cross-sectional dimension in the low-profile
configuration, a desired outward spring force to self-expand to the
expanded configuration, and a desired hoop strength to support the
frame 104 in the expanded configuration. For example, in some
embodiments, the wires 426 can have a diameter from approximately
0.007 inch to approximately 0.014 inch. In specific embodiments,
the wires have a diameter from approximately 0.011 inch to 0.013
inch. In other embodiments, the wires 426 can have a smaller
diameter, a greater diameter, and/or the diameter of the wires 426
can vary along the length of the frame 104. For example, in one
embodiment, the wires 426 can have a greater diameter at the
superior portion 108 than at the inferior portion 110 such that the
wires 426 of the superior portion 108 have a outward spring force
and greater hoop strength where the first and second endograft
devices mate (e.g., at the septal walls 114) and the increased
density of wires 426 at the inferior portion 110 does not
negatively impact the flexibility of the frame 104.
[0063] The frame 104 may be constructed from a variety of resilient
metallic materials, polymeric materials (e.g., polyethylenes,
polypropylenes, Nylons, PTFEs, and the like), and composites of
materials. For example, the wires 426 can be made from
biocompatible stainless steels, highly elastic metallic alloys, and
biocompatible shape setting materials that exhibit shape memory
properties. In some embodiments, for example, the wire 426 can be
made from a shape setting alloy, such as Nitinol, that has a
preferred or native configuration. For example, a Nitinol structure
can be deformed or constrained into a secondary configuration, but
upon release from the constraint, the structure returns toward its
native configuration with high fidelity. Accordingly, a frame 104
made from Nitinol wires 426 can reliably self-expand from the
low-profile configuration the expanded configuration (i.e., its
native configuration).
[0064] For endovascular delivery of a device (e.g., the endograft
devices 102 shown in FIGS. 1A and 1B), the frame 104 is extended to
constrict the frame 104 into a low-profile configuration in which
the frame 104 can be loaded into a delivery device. The braid angle
.theta. of the wires 426 can facilitate significant extension of
the frame 104 to produce a slender profile during delivery as
described above, and yet the interwoven characteristic of the braid
restricts over extension. This extension-constriction functionality
of the frame 104 allows the frame 104 to have variable diameters
(e.g., the diameter of the superior portion 108 compared to the
diameter of the inferior portion 11) using the same number of wires
426 on each portion of the frame 104 such that the frame 104 has a
low introduction profile (e.g., diameter) along the length of the
frame 104. The frame 104 can also include an optimal number of
loops 428 at each end portion 118 such that the loops 428 do not
increase the profile of the frame 104 upon full extension.
[0065] At a target site (e.g., above an aneurysm), the frame 104
self-expands to the expanded configuration shown in FIG. 4A as it
is removed from the delivery device. The braid angle .theta. can be
adjusted to change the outward spring force and hoop, strength of
the expanded frame 104 as explained above. In some circumstances,
the endograft device may need to be repositioned after being
partially deployed. The frame 104 is well suited for such
repositioning because the loops 428 and the continuous, interwoven
wires 426 can simplify recapture of the frame 104 and allow for
constriction after expansion to correctly reposition the endograft
device. Additionally, portions of the frame 104 can remain exposed
(e.g., the end portions 118) to encourage cell ingrowth for
securely anchoring the frame 104 to the arterial walls. Moreover,
as described in more detail below, the interwoven wires 426 of the
braided frame 104 can provide a continuous longitudinal support
along the length of the frame 104 such that the frame 104 can be
staggered and free end portions can support themselves. The frame
104 can also facilitate attachment to other endograft devices. For
example, the frame 104 can interlace with another interwoven wire
426 of a supra-renal endograft.
[0066] Once deployed across the aneurysm, the frame 104 can also
accommodate disparate anatomies and morphologies. In several
patients, the aneurysmal sac extends at an angle with respect to
the neck of the aneurysm. Because the frame 104 can have a braid
angle .theta. that prevents kinking, the frame 104 can bend and
flex without kinking to accommodate angulated aneurysmal sacs
without restricting blood flow. Additionally, the unbound, woven
wires 426 give the frame 104 a radial elasticity such that the
frame 104 mimics the changes in the shape and morphology of the
aorta without hindering the interface or seal between the endograft
device and the vessel wall. For example, the frame 404 can
constrict and expand to maintain the seal when pressure and other
conditions alter the vasculature of the aorta. Moreover, the woven
wires 426 inherently generate a spring force that biases the frame
104 toward a substantially straight trajectory within an aneurysmal
sac and thereby limits migration of the endograft device.
[0067] In addition, the constant outward spring force and hoop
strength of the braided frame 104 can be adjusted by changing the
braid angle .theta. and/or the diameter of the wires 426. This
allows the formation of large diameter frames 104 without a
significant change in the low-profile cross-sectional dimensions.
Additionally, this feature allows the frames 104 to contract to a
much smaller introduction profiles (e.g., diameters) compared to
standard Z-frames or M-frames because the standard Z-frames and
M-frames tend to require more wire and therefore larger
introduction profiles to maintain a constant outward spring force
and hoop strength.
[0068] 2.2 Covers
[0069] FIGS. 5A-C are views of a cover being extended from an
expanded configuration (FIG. 5A) to a low-profile configuration
(FIG. 5C) in accordance with embodiments of the technology. More
specifically, FIG. 5A is a side view of the cover 106 described
above with reference to FIGS. 1A and 1B in the expanded
configuration. The cover 106 can include a plurality of
circumferential ribs 530 such that the cover 106 has an undulating
profile. As shown in FIG. 5A, the individual ribs 530 can have a
substantially triangular shape with an apex 533. In other
embodiments, the individual ribs 530 have rounded edges,
rectangular edges, and/or other suitable textures that can extend
and contract.
[0070] The ribs 530 of one cover can mate with opposing ribs 530 of
an opposing cover and interface with vessel walls to enhance the
seal and fixation between endograft devices in an endograft system
(e.g., the endograft devices 102 of the endograft system 100 shown
in FIGS. 1A and 1B) and between the endograft devices and the
arterial walls. For example, the apices 533 of the ribs 530 at the
septal wall 114 of the superior portion 108 of one endograft device
can interface or mate with the troughs of the corresponding ribs
530 on a cover of an opposing endograft device. Additionally, the
ribs 530 at the outer wall 112 can contact the arterial walls in a
manner that at least substantially seals them together. The ribs
530 can also allow the cover 106 to flex and bend without wrinkling
in situ. In some embodiments, the ribs 530 can be at only selected
portions of the cover 106 (e.g., the septal wall 114). In other
embodiments, the ribs 530 can have different shapes and/or
geometries on different portions of the cover 106. For example, the
apices 533 of the ribs 530 can have a first height on the superior
portion 108 to enhance sealing forces between the endograft devices
and a second height less than the first height at the inferior
portion 110 to allow the cover 106 to freely flex and bend to
accommodate the anatomy.
[0071] The ribs 530 change with the expansion and contraction of
the cover 106. As shown in FIG. 5A, the apices 533 of the ribs 530
protrude to the maximal extent in the expanded configuration.
Referring to FIG. 5B, as the cover 106 extends, the ribs 530 also
extend and constrict. When the cover 106 is fully extended in the
low-profile configuration shown FIG. 5C, the ribs 530 are
completely elongated and constricted. In some embodiments, the size
of each rib 530 can be predetermined to ensure the ribs 530 are
completely flattened in the low-profile configuration and project
radially outwardly to interface with adjacent surfaces in the
expanded configuration. Accordingly, the ribs 530 do not limit the
mobility of the endograft device as it is delivered to the aorta in
the low-profile configuration.
[0072] Additionally, as shown in FIGS. 5A-C, the cover 106 can
include zigzagged edges at a superior terminus 531a and an inferior
terminus 531b of the cover 106. The zigzagged termini 531 can
facilitate substantially seamless attachment between the cover 106
and an integrated frame (e.g., the frame 104 shown in FIGS. 4A and
4B). For example, in some embodiments, the zigzagged termini 531
can correspond to the braid angle .theta. of interwoven wires. The
zigzagged termini 531 generally prevent the cover 106 from
wrinkling or bunching at first and second end portions (e.g., the
first and second end portions 118a and 118b shown in FIGS. 4A and
4B) when the cover 106 and the frame are constricted. In other
embodiments, the superior and inferior termini 531a and 531b can be
scalloped, straight, and/or have another suitable shape that
facilitates attachment and/or limits wrinkling.
[0073] The cover 106 can be made from a substantially impermeable,
biocompatible, and flexible material. For example, the cover 106
can be made from synthetic polymers, polyurethanes, silicone
materials, polyurethane/silicone combinations, rubber materials,
woven and non-woven fabrics such as Dacron.RTM., fluoropolymer
compositions such as a polytetrafluoroethylene (PTFE) materials,
expanded PTFE materials (ePTFE) such as TEFLON.RTM., GORE-TEX.RTM.,
SOFTFORM.RTM., IMPRA.RTM., and/or other suitable materials.
Additionally, in some embodiments, the cover 106 can be made from a
material that is sufficiently porous to permit ingrowth of
endothelial cells. Such a porous material can provide more secure
anchorages of endograft devices and potentially reduce flow
resistance, sheer forces, and leakage of blood around the endograft
devices.
[0074] In some embodiments in accordance with the technology, the
cover 106 may also include drug-eluting coatings or implants. For
example, the cover 106 can be coated and/or imbedded with a
slow-releasing drug that can block cell proliferation, promote
reendothelialization of the aneurysm, and/or otherwise medicate the
aneurysmal region. Suitable drugs can include calcium, proteins,
mast cell inhibitors, and/or other suitable medicines that
encourage beneficial changes at the aneurysmal region.
[0075] In accordance with other embodiments of the technology, the
cover 106 can be eliminated in favor of one or more layers of a
coating material (shown and described in more detail with reference
to FIGS. 17A-E). The coating layer can be made from a biocompatible
synthetic polymer, such as PTFE. The coating layer can be placed on
the interior of an integrated frame (e.g., the frame 104 shown in
FIGS. 4A and 4B), the exterior of the frame, and/or interwoven
throughout the frame. Like the cover 106, the coating layers can
encase the frame to form a lumen (e.g., the lumen 116 shown in
FIGS. 1A and 1B). Additionally, the coating can have a selected
porosity that encourages tissue ingrowth.
[0076] 2.3 Integrated Frame and Cover
[0077] FIGS. 6A and 6B are cross-sectional views of the endograft
device 102 of FIGS. 1A and 1B in a low-profile configuration and an
expanded configuration, respectively, in accordance with
embodiments of the technology. As shown in FIGS. 6A and 6B, the
cover 106 can be attached to the exterior of the frame 104 at one
or more attachment areas 632 (identified individually as a first
attachment area 632a and a second attachment area 632b). The
attachment areas 632 can have sutures, adhesives, welds, and/or
other suitable fasteners that discretely hold the cover 106 to the
frame 104 at the attachment areas 632.
[0078] In the embodiment shown in FIGS. 6A and 6B, the endograft
device 102 has attachment areas 632 at only the superior and
inferior termini 531a and 531b of the cover 106 such that the
remainder of the cover 106 between the attachment areas 632 is not
attached directly the frame 104. As a result, the frame 104 and the
cover 106 can fully extend and constrict as shown in FIG. 6A
without interfering with one another. For example, in the
low-profile configuration shown in FIG. 6A, the frame 104 does not
directly pull the central portion of the cover 106 downward and
longitudinally with the frame 104 such that the ribs 530 can
stretch uniformly along the length of the cover 106 to accommodate
full extension of the frame 104. Similarly, the intermediate
portions of the cover 106 do not hinder the extension or
constriction of the frame 104. Fewer attachments areas 632 can also
limit the potential for fatigue and undesirable porosity that may
arise at the attachment areas 632, such as from needle pricks and
other fastening mechanisms that puncture the cover 106.
[0079] As shown in FIG. 6B, the cover 106 can substantially conform
to the shape of the frame 104 when they are in the expanded
configuration. Proper alignment between the cover 106 and the frame
104 prevents the cover 106 from adversely affecting constriction
and expansion. For example, alignment between the cover 106 and the
frame 104 at the superior and transition portions 108 and 324,
respectively, ensures the frame 104 can expand properly and
generate the force necessary to mate with a superior portion of an
opposing endograft device. Additionally, in some embodiments, the
cover 106 is sized to restrict the expansion and corresponding
contraction of the frame 104.
[0080] Attaching the cover 106 to the exterior of the frame 104 as
shown in FIGS. 6A and 6B can provide a plurality of benefits for
the endograft device 102. For example, unlike endograft devices
with internal covers that must fold within a frame during delivery,
the exterior cover 106 does not inhibit constriction of the frame
104 (e.g., FIG. 6A). In the expanded configuration, the exterior
the cover 106 does not bunch or wrinkle within the frame 104, and
thus does not cause thrombotic problems within the lumen 116.
Additionally, unlike more rigid Z-stents, the flexibility of the
frame 104 can prevent abrasive rubbing and deterioration of the
cover 106 in the expanded configuration (e.g., FIG. 6B). The
exterior attachment of the cover 106 can also prevent over
expansion of the frame 104.
[0081] 2.4 Alignment Aids
[0082] FIGS. 7A and 7B are isometric views of endograft devices 702
in accordance with additional embodiments of the technology. The
endograft devices 702 can have generally similar features as the
endograft devices 102 shown in FIGS. 1A and 1B. Additionally, the
endograft devices 702 can include alignment aids 734 that are
visible under imaging systems (e.g., X-rays) to facilitate accurate
positioning and subsequent monitoring of the endograft devices 702
in the vasculature.
[0083] FIG. 7A is a partial cut-away isometric view of the
endograft device 7-2 showing an alignment aid 734 in accordance
with an embodiment of the technology. As shown in FIG. 7A, the
alignment aid 734 can extend diagonally along the septal wall 114
of the frame 104 to indicate the position of the septal wall 114
relative to the endograft device 702. The alignment aid 734 can
thus provide an indication of the rotational orientation and axial
location of the endograft device 702 such that during deployment
opposing septal walls 114 can be properly aligned and mated with
one another. Additionally, as shown in the embodiment in FIG. 7A,
the alignment aid 734 can terminate at the superior terminus 531a
of the cover 106 to indicate where the first end portion 118a
begins. Thus, the alignment aid 734 provides a definitive indicator
to ensure that the cover 106 does not block transverse flow (e.g.,
from the aorta to the renal arteries). In other embodiments, the
alignment aids 734 may be positioned elsewhere along the endograft
device 702 to provide spatial location and orientation that can aid
delivery and deployment of the endograft device 702.
[0084] The alignment aid 734 can be made from radiopaque and/or
fluoroscopic materials, such as tantalum, platinum, gold, and/or
other materials that are visible under an imaging system (e.g.,
X-rays). For example, as shown in FIG. 7A, the alignment aid 734 is
made from a radiopaque wire (e.g., tantalum) wound around a segment
of the frame 104. In another embodiment, a radiopaque composition
is applied to the frame 104 and/or incorporated in the septal walls
114 of the cover 106.
[0085] FIG. 7B shows the first and second endograft devices 702
mated together using the alignment aids 734 in accordance with an
embodiment of the technology. As shown in FIG. 7B, the alignment
aids 734 on the first and second endograft devices 702a and 702b
are symmetrical such that when the endograft devices 702 are
correctly oriented and the septal walls 114 oppose one another, the
alignment aids 734 can intersect to form an "X" indicator. In other
embodiments, the intersection of the alignment aids 734 forms other
characters, numbers, and/or symbols that indicate the rotational
orientation and longitudinal location of the endograft devices 702.
In further embodiments, the alignment aids 734 can be applied to
different portions of the septal wall (e.g., the cover 102) and/or
the outer wall 112. In still further embodiments, the endograft
devices 702 include a plurality of alignment aids 734 to
distinguish different portions of the endograft devices 702 and
further aid rotational and/or other orientation. For example, in
some embodiments, the inferior portions 110 include alignment aids
734 that differentiate the inferior portions 110 of the first and
second endograft devices 702.
[0086] 2.5 Anchors
[0087] FIGS. 8A and 8B are isometric views of endograft devices 802
configured in accordance with additional embodiments of the
technology. The endograft devices 802 can include generally similar
features as the endograft devices 102 shown in FIGS. 1A and 1B.
Additionally, the endograft devices 802 can include one or more
anchors 836 that project outwardly from the frame 104 and/or cover
106 to engage the interior surfaces of arterial walls. The anchors
836 can be barbs, hooks, and or other shapes that can penetrate
into the arterial walls. For example, as shown in FIG. 8A, the
anchors 836 can be "V" shaped projections. In some embodiments, the
anchors 836 eventually become embedded in cell growth on the
interior surface of the arterial wall. In operation, the anchors
836 resist migration of the endograft devices 802 within the artery
and reduce the likelihood of endoleaks between the outer wall 112
and the arterial wall.
[0088] In an embodiment shown in FIGS. 8A and 8B, the anchors 836
project from the outer walls 112 to secure the superior portions
108 to the aorta. In other embodiments, additional anchors 836 can
project from the second end portions 118b to secure the inferior
portions 110 to the iliac arteries. The anchors 836 can also
protrude from the septal walls 114, extend through the lumen 116,
and project outward beyond the outer wall 112 to enhance the
strength of the engagement. The anchors generally project
inferiorly such that downward forces applied to the endograft
devices 802 (e.g., blood flow) drive the anchors 836 further into
the arterial walls.
[0089] In one embodiment in accordance with the technology, the
anchors 836 are separate elements that are attached to the frame
104. For example, in the embodiment shown in FIG. 8A, the anchors
836 are small barbs or wires that are fastened to the frame 104 by
winding another wire (e.g., a Nitinol wire) around the anchors 836
and the adjacent wire 426 of the braid. In other embodiments, the
anchors 326 are integrally formed with the wire 426 used in the
braid of the frame 104. For example, as shown in FIG. 8B, the
anchors 836 are woven into the outer wall 112 of the frame 104. The
interwoven anchors 836 can be deployed (i.e., project outwardly)
when the frame 104 expands and can retract when the frame 104
constricts. Accordingly, the interwoven anchors 836 do not inhibit
movement of the endograft device 802 during delivery in the
low-profile configuration. In other embodiments, the anchors 836
can be attached to a different portion of the endograft device 802
(e.g., the cover 106).
[0090] The anchors 836 can be made from resilient metallic
materials, polymeric materials (e.g., polyethylenes,
polypropylenes, Nylons, PTFEs), and/or other suitable materials
that can anchor the endograft devices 802 to arterial walls. For
example, the interwoven anchors 836 shown in FIG. 8B can be made
from Nitinol wire 426 that comprises the frame 104.
[0091] 3. Methods of Implementation and Assembled Endograft
Systems
[0092] Described below are methods of deploying and assembling
modular endograft systems across an aneurysm in accordance with
embodiments of the technology. The associated Figures (i.e., FIGS.
9A, 9B, 11-13C and 15A-16) include schematic representations of an
abdominal portion of an aorta. More specifically, FIG. 9A shows an
aneurysm 50 located along an infrarenal portion of the aorta 52,
which is the most common site of an AAA. A right or first renal
artery 54a and a left or second renal artery 54b stem from the
aorta 52. The region of the aorta 52 superior to the aneurysm 50
and inferior to the renal arteries 54 is the aortic neck 60. The
distal end portion of the aorta 52 bifurcates into common iliac
arteries 56 (identified individually as a first iliac artery 56a
and a second iliac artery 56b), and the internal iliac arteries 58
(identified individually as a first internal iliac artery 58a and a
second internal iliac artery 58b) branch from the common iliac
arteries 56. Other arteries and structures proximate to the
abdominal portion of the aorta 52 have been removed for
clarity.
[0093] 3.1 Modular Endograft Systems
[0094] FIGS. 9A and 9B are schematic views of the two-part modular
endograft system 100 described above being deployed across the
aneurysm 50 in accordance with an embodiment of the technology.
FIG. 9A shows a delivery system 40 for implanting the first and
second endograft devices 102a and 102b. The delivery system can
include a first catheter 42a, a first guidewire 44a associated with
the first catheter 42a, a second catheter 42b, and a second
guidewire 44b associated with the second catheter 42b. Each
endograft device 102 (FIG. 9B) can be extended to the low-profile
configuration and loaded into the corresponding catheter 42.
Because the endograft devices 102 are delivered separately, the
sizes of the catheters 42 are not constrained by the system 100 as
a whole. In some embodiments, for example, the low-profile
configurations of each endograft device 102 can fit within a 12 F
catheter. In other embodiments, the low-profile configuration of
the endograft devices 102 can fit within differently sized
catheters 42.
[0095] During deployment, the first catheter 42a and the first
guidewire 44a are inserted percutaneously into a blood vessel
(e.g., a femoral artery; not shown). With the aid of imaging
systems, the first guidewire 44a is endoluminally navigated through
the vasculature, up the first iliac artery 56a, and to a location
superior to a target site T above the aneurysm 50. The first
catheter 42a is then passed through the vasculature along the first
guidewire 44a to the target site T. Using a generally similar
method, the second guidewire 44b and the second catheter 42b are
delivered through the second iliac artery 56b to the target site T.
The first and second endograft devices 102a and 102b can be
delivered simultaneously or in succession.
[0096] The endograft devices 102 can be urged out of the distal
ends of the catheters 42 at the target site T by withdrawing the
catheters 42 proximally while holding the endograft devices 102 in
place using pushers or other suitable endovascular instruments.
Alternatively, the endograft devices 102 can be pushed distally
while holding the catheters 42 in place. Upon release, the
endograft devices 102 self-expand to the expanded configuration
shown in FIG. 9B. The guidewires 44 generally remain in place to
facilitate adjusting the endograft devices 102. This eliminates the
need to cannulate either of the endograft devices 102.
[0097] Each endograft device 102 can be positioned at its desired
location independently of the other endograft device 102 while the
endograft devices 102 are in, or at least partially within, the
catheters 42. For example, in the embodiment illustrated in FIG.
9B, the superior portions 108 contact the aortic neck 60 at the
same level, and the inferior portions 110 extend through the
aneurysm 50 to their respective iliac arteries 56. More
specifically, the inherent hoop force of the frame 104 caused by
the constant outward spring force of the braid at least
substantially seals (a) the covers 106 at the outer walls 112
against the aortic neck 60 and (b) the septal walls 114 to each
other to form the septum 120. The inferior portions 110 extend
through the aneurysm 50 and can bend to enter the iliac arteries
56. The proximal portion of the inferior portions 110 contact the
iliac arteries 56 and can form a seal therebetween. The flexibility
of the frame 104 prevents the endograft devices 102 from kinking at
the bend and restricting blood flow. Additionally, as shown in FIG.
9B, the spring force within the frame 104 biases the inferior
portions 110 to extend in a substantially straight trajectory
through the aneurysm 50. This inhibits migration of the inferior
portions 110 to a side of the aneurysm 50 that could break the
contact and/or seal at the aortic neck 60. As described in more
detail below, in other embodiments the endograft devices 102 can be
positioned independently at different elevations along the aortic
neck 60.
[0098] As further shown in FIG. 9B, the endograft system 100 can
include extension units 937 (identified individually as a first
extension unit 937a and a second extension unit 937b) projecting
distally from the superior termini 531 of the covers 106. The
extension units 937 can include an extension frame 904 (not
visible) and an extension cover 906 at least generally similar to
the frame 104 and the cover 106 of the endograft devices 102
described above. The extension units 937 can have a substantially
similar shape as the superior portions 108 of the endograft devices
(e.g., a D-like shape) such that the extension units 937 can mate
with the interior of at least a part of the superior portions 108.
For example, as shown in FIG. 9B, the extension covers 906 can be
positioned inferior to the renal arteries 54 within the frame 104
such that the extension covers 906 can interface with the aortic
neck 60 and mate with one another to extend the septum 120
distally. Therefore, the extension units 937 can increase the
fixation area and the sealing area of the endograft devices 102
when the superior termini 531 of the covers 106 of the endograft
devices 102 are offset from the entrances of the renal arteries 54.
For example, in some embodiments, the extension units 937 add
approximately one inch of fixation structure and sealing area to
the endograft devices 102. In other embodiments, the inferior
portions 110 can also include extension units 937 that can affix
and at least substantially seal to the iliac arteries 56.
[0099] During deployment, the extension units 937 can be added to
the system 100 after the first and second endograft devices 102 are
positioned within the aortic neck 60. With the aid of the delivery
system 40, the extension units 937 can advance along the guidewires
44 and be deployed from the catheters 42 at desired positions
within the first and second frames 104 just inferior of the renal
arteries. Upon deployment, the extension units 937 can self-expand
via an inherent spring force in the extension frame 904 to an
expanded configuration to contact and at least substantially seal
with the interior of the superior portions 108 of the endograft
devices 102. As shown in FIG. 9B, the extension cover 906 can
interface with the first end portions 118a of the frames 104 to
strengthen the seal therebetween. In other embodiments, the
extension units 937 can connect and seal to the endograft devices
102 using other suitable attachment methods. The extension units
937 can be positioned independently such that they accommodate
anatomical variations (e.g. staggered renal arteries). For example,
a superior terminus of the first extension unit 937a can be
longitudinally offset from a superior terminus of the second
extension units 937b. Similarly, the inferior portions 110 can
include extension units 937 that increase the sealing area with the
iliac arteries 56.
[0100] In some embodiments, alignment aids, such as the alignment
aids 734 described with reference to FIGS. 7A and 7B, are used to
rotationally orient the endograft devices 102 and align the septal
walls 114 during delivery. Additionally, to prevent migration
and/or projection of the system while in situ, anchors, such as the
anchors 836 described above with reference to FIGS. 8A and 8B, can
be deployed from the outer walls 112 to engage the arterial walls
of the aortic neck 60 and/or from the second end portions 118b to
engage the arterial walls of the iliac arteries 56.
[0101] FIGS. 10A-11 show additional embodiments of implementing
endograft systems (e.g., the system 100) in which the superior
portions 108 are longitudinally offset from each other. For
example, in some embodiments, the superior portions 108 are
longitudinally offset by at least 5 mm. The features of the systems
below allow one or both of the superior portions 108 to be placed
over transverse arteries to increase the available fixation
structure and sealing area for the endograft devices 102 without
inhibiting blood flow.
[0102] FIG. 10A is an isometric view of the modular endograft
system 100 in which the endograft devices 102 are staggered such
that the superior portion 108 of the first endograft device 102a is
above the superior portion 108 of the second endograft device 102b.
The first end portion 118a of the second endograft device 102b can
prevent the unsupported free first end portion 118a of the first
endograft device 102a from splaying outward into the blood flow in
a manner that induces undo turbulence. Moreover, the interplay
between the woven wires 426 of the frame 104 of the first endograft
device 102a restricts the outward movement of the first end portion
118a of the first endograft device 102a and provides substantially
continuous support along the length of the frame 104 such the free
first end portion 118a retains substantially the same shape as if
it were supported. These features maintain the generally straight
or convex shape of the unsupported septal region of the first
portion 118a of the first endograft device 102a. Using
shape-setting Nitinol wire 426 in the frame 104 can further
facilitate maintaining the shape of the unsupported portion of the
frame 104.
[0103] Compared to conventional devices that have a common height
across the diameter of a vessel (e.g., the aorta), the staggered
configuration shown in FIG. 10A allows one or both of the first end
portions 118a to extend over the entrance of the renal arteries to
increase the available structure for fixing the endograft devices
102 to the vessel wall. The staggered configuration also increases
the sealing area of the superiorly positioned first endograft
device 102a for anatomies having a short aortic neck (e.g., less
than 2 cm). Similarly, the second end portions 118b can extend over
the entrances of the internal iliac arteries to ensure the inferior
portions 110 each have an adequate structure for fixing and at
least substantially sealing the inferior portions 110 to the iliac
arteries. To the extent migration occurs, the additional sealing
area between the endograft devices 102 and the vessel walls will
reduce the potential for leakage at the aortic neck.
[0104] FIG. 10B is an isometric view of a modular endograft system
1000 configured in accordance with an additional embodiment of the
technology. The system 1000 can have a first endograft device 1002a
and a second endograft device 1002b that are generally similar to
the endograft devices 102 described above. The covers 106 of the
endograft devices 1002 in FIG. 10B, however, extend to the distal
ends of the superior portions 108. Additionally, the endograft
devices 1002 further include fenestrations 1038 on the outer walls
112 of the superior portions 108.
[0105] The fenestrations 1038 can be openings through the cover 106
that expose the frame 104 and provide a channel through which blood
can flow to and from transverse arteries. For example, the
endograft devices 1002 can be positioned independently and
staggered such that the fenestration 1038 of each endograft device
1002 is aligned with one of the left or right renal arteries. The
fenestrations 1038 accordingly increase the available sealing area
between the outer walls 112 and the arterial walls because the
superior portions 108 can be positioned independently over the
renal arteries such that one endograft device 1002 does not need to
be limited to the elevation of the inferior renal artery. This
provides optimal placement for each endograft device 1002 within
the vasculature without requiring customized devices. In other
embodiments in accordance with the technology, the endograft
devices 1002 can include additional fenestrations 1038 to increase
the available sealing area without restricting blood flow. For
example, the inferior portions 110 can include fenestrations 1038
that allow the inferior portions 110 to extend over the entrance of
the internal iliac arteries.
[0106] FIG. 11A is a schematic view of the modular endograft system
100 deployed across an aneurysm such that the superior portions 108
of the endograft devices 102 are staggered to accommodate for
anatomical variations in the vasculature in a manner that takes
advantage of the available structure for fixing the endograft
devices 102 to arterial walls and the available sealing area in the
aortic neck 60. In the embodiment shown in FIG. 11A, for example,
the left renal artery 54b is inferior the right renal artery 54a.
The first endograft device 102a can, therefore, also be positioned
higher in the aorta 52 to utilize the available fixation and
sealing areas on the ipsilateral side of the aortic neck 60 without
having to be concerned about blocking the entrance of the left
renal artery 54b. The first end portion 118a of the second
endograft device 102b can be positioned over the left renal artery
54b without inhibiting blood flow to lengthen the structure for
fixing the second endograft device 102b to the arterial wall and
mating the septal walls 114 together. The longer fixation and
sealing areas along the outer wall 112 of the first endograft
device 102a and the longer mating and sealing areas between the
septal walls 114 can strengthen the seals of the system 100 as a
whole to reduce the likelihood of endoleaks. Additionally, as shown
in FIG. 11A, the system 100 can be staggered to accommodate an
anatomy with less fixation and sealing area in one of the iliac
arteries 56.
[0107] FIG. 11B is a schematic view of the modular endograft system
1000 of FIG. 10B deployed across the aneurysm 60. Similar to the
configuration of the system 100 shown in FIG. 11A, the endograft
devices 1002 are staggered to accommodate for anatomical variations
in the vasculature in a manner that takes advantage of the
available anatomical structure for fixing and sealing the outer
walls 112 of the endograft devices 102 to the arterial walls in the
aortic neck 60. As shown in FIG. 11B, for example, the first
endograft device 1002a can be positioned superior to the second
endograft device 1002b in the aortic neck 60 to utilize the
available fixation and sealing area on the ipsilateral side of the
aortic neck 60. The fenestrations 1038 can be placed independently
at the entrance of each renal artery 54 to increase the available
fixation and sealing area in the aortic neck 60 and accommodate
asymmetrical anatomies. Additionally, as further shown in FIG. 11B,
the endograft devices can include fenestrations 1038 at the
inferior portions 110 that can be placed independently at the
entrance of each internal iliac artery 58 to accommodate an anatomy
with less sealing area in the iliac arteries 56. In other
embodiments, the endograft devices 102 can include fenestrations
1038 to accommodate other anatomical variations.
[0108] FIG. 12 is a schematic view of the modular endograft system
of FIGS. 9A and 9B deployed across an angulated aneurysm in
accordance with an additional embodiment of the technology. The
system 100 can accommodate this anatomical abnormality because the
endograft devices 102 are flexible. More specifically, the
interwoven wires 426 of the frame 104 are sufficiently flexibility
to bend without kinking. Thus, the bent endograft devices 102 can
maintain unrestricted flow through the lumens 116. Accordingly, the
system 100 can accommodate other anatomical variations that may
require the endograft devices 102 to flex or bend without
disturbing blood flow.
[0109] FIGS. 13A-C are schematic views of a four-part modular
endograft 1300 system ("system 1300") being deployed across the
aneurysm 50 in accordance with an embodiment of the technology. The
system 1300 can include generally similar features as the system
100 described with reference to FIGS. 9A and 9B. However, as shown
in FIG. 13B, the inferior portions 110 of the endograft devices 102
terminate within the aneurysm 50. Therefore, as shown in FIG. 13C,
the system 1300 further includes separate limbs 1362 (identified
individually as a first limb 1362a and a second limb 1362b) that
contact and substantially seal with corresponding inferior portions
110 and extend into corresponding iliac arteries 56. The limbs 1362
can be generally similar to the inferior portions 110. For example,
the limbs 1362 can include an integrated frame 1304 and a cover
1306 generally similar to the frame 104 and the cover 106 described
above with reference to FIGS. 1A-6B. As shown in FIG. 13C, the
limbs 1362 self-expand within the interior portions 110 to the
expanded configuration and thereby the superior portions of the
limbs 1362 at least substantially seals to the proximal section of
the inferior portions 110. The length of the limbs 1362 within the
inferior portions 110 can be adjusted to increase the available
structure for fixing and sealing the limbs 1362 to the endograft
devices 102. Additionally, in some embodiments, the covers 1306 of
the limbs 1362 can include ribs, such as the ribs 530 described
above with reference to FIGS. 5A-C, that interface with the
interior of the frames 104 and the covers 106 at the inferior
portions 110 to connect and at least substantially seal the limbs
1362 to the inferior portions 110. In other embodiments, the limbs
1362 can connect and at least substantially seal to the exteriors
of the inferior portions 110 using anchors (e.g., the anchors 836
described with reference to FIGS. 8A and 8B), self-constricting
forces, and/or other suitable attachment and sealing methods. The
limbs 1362 extend the lumens 116 of the endograft devices 102 to
the iliac arteries 56 such that blood can flow through the system
1300 to bypass the aneurysm 50.
[0110] Referring to FIG. 13A, the delivery system 40 is shown
within the abdominal portion of the aorta 52 before deploying the
endograft system 1300. The insertion of the delivery system 40 can
be generally similar as described above with reference to FIG. 9A.
However, as shown in FIG. 13A, the first and second guidewires 44a
and 44b can cross after they enter the aneurysm 50 such that each
catheter 42 extends from its respective iliac artery 54 to the
contralateral side of the aorta 52. For example, the first catheter
42a can be delivered from the first iliac artery 56a to the left
side of the aorta 52 proximate to the left renal artery 54b (Arrow
D.sub.1), and the second catheter 42b can be delivered from the
second iliac artery 56b to the right renal artery 54a (Arrow
D.sub.2). In other embodiments, such as in the deployment method
described above with reference to FIGS. 9A and 9B, the guidewires
44 do not cross within the aneurysm 50.
[0111] Referring to FIG. 13B, after the first and second catheters
42a and 42b are positioned in the aortic neck 60, they are pulled
proximally to deploy the endograft devices 102 through the distal
ends of the catheters 42. The crossing catheters 42 and guidewires
44 deploy the endograft devices 102 on opposite sides of the aortic
neck 60.
[0112] As shown in FIG. 13B, the inferior portions 110 of the
endograft devices 102 terminate within the aneurysm 50 and form a
"gate." In general, gates are considered undesirable because in
conventional systems they must be cannulated to deliver and deploy
limbs that extend the endograft devices into the iliac arteries 56.
However, as shown in FIG. 13B, the guidewires 44 remain within the
endograft devices 102 after they are deployed; this eliminates the
need for time-consuming cannulation of the gates because the
inferior portions 110 of the endograft devices 102 are in effect
pre-cannulated. Such pre-cannulated gates allow the limbs 1362 to
be delivered through the distal ends of the catheters 42 and
connected to the inferior portions 110 much faster and more
accurately than conventional systems.
[0113] FIG. 13C shows the system 1300 after both limbs 1362 are
connected to the endograft devices 102. As shown in FIG. 13C, the
delivery system 40 can also be used to adjust the length of the
limbs 1362 and the length of the fixation area between the limbs
1362 and the inferior portions 110 in the direction of the arrows.
In the embodiment shown in FIG. 13C, for example, the second limb
1362b extends further into the inferior portion 110 of the second
endograft device 102b such that the second limb 1362b is
effectively shorter than the first limb 1362a. The length of the
limbs 1362 can be adjusted to accommodate disparate anatomies of
the iliac arteries 56, maximize the fixation and sealing areas of
the limbs 1362, and/or otherwise optimize the position of the limbs
1362. This is possible because, at least in part, the inferior
portions 110 of the endograft devices 102 can be relatively long to
allow significant longitudinal leeway in positioning the limbs 1362
while still providing adequate surface area to at least
substantially seal the limbs 1362 to the inferior portions 110.
[0114] The four-part, two-wire system 1300 can easily accommodate
anatomical variations without requiring customized components. For
example, the superior portions 108 can be staggered to maximize the
mating and sealing area of each outer wall 112 with the aortic
walls. Additionally, each limb 1362 can be selected from a
relatively small number of different lengths to extend a desired
length within the iliac arteries 56 that both adequately connects
and substantially seals the limbs 1362 to the arterial walls and
does not block transverse arterial flow. The limbs 1362 can also be
adjusted independently relative to the inferior portions 110 to
increase the available structure for fixing and sealing the limbs
1362 and the inferior portions 110 together, and to shorten or
lengthen the limbs 1362 within the iliac arteries 56. Additionally,
the braided structure of the frames 104 can decrease infolding of
the covers 106 such that the lengths of the frame 104 can be
selected from standardized cross-sectional dimensions. Thus, the
four-part system 1300 can be highly customizable, but yet comprise
standardized components.
[0115] 3.2 Modular Endograft System with Aortic Cuff
[0116] FIGS. 14A and 14B are isometric views of a modular endograft
system 1400 ("system 1400" shown in FIG. 14B) configured in
accordance with embodiments of the technology. More specifically,
FIG. 14A is an isometric view of an aortic cuff 1464 for use with
the endograft devices 102 (FIG. 14B). The aortic cuff 1464 can
include a sleeve 1466 and a cuff frame 1468. As shown in FIG. 14A,
the sleeve 1466 and the cuff frame 1468 can be separate components.
In other embodiments, the sleeve 1466 and the cuff frame 1468 can
be formed integrally. The aortic cuff 1464 can expand from a
low-profile configuration having a first cross-section to an
expanded configuration (e.g., FIG. 14B) having a second
cross-section larger than the first cross-section. The low-profile
configuration can be used during delivery of the aortic cuff 1464
from which the cuff-device 1464 can self-expand to the expanded
configuration in situ. The aortic cuff 1464 can be configured to
interface and substantially seal with an infrarenal portion of the
aorta superior to an aneurysm.
[0117] The sleeve 1466 can be attached to the interior and/or
exterior of the cuff frame 1468 using suitable fastening methods.
For example, as shown in FIG. 14B, the sleeve 1466 is positioned
within the interior of the cuff frame 1468, and the ends of the
sleeve 1466 extend over and are fixed to proximal and distal ends
of the cuff frame 1468 using suitable fastening methods (e.g.,
stitching, gluing, welding, etc.). In some embodiments, the
proximal and distal ends of the cuff frame 1468 can be flared, and
the sleeve 1466 can wrap around the flared ends to the exterior of
the cuff frame 1468 such that the attachment can be sealed by the
arterial walls when the aortic cuff 1464 is expanded to the
expanded configuration in situ. The sleeve 1466 can have generally
similar characteristics as the cover 106 described above. For
example, the sleeve 1466 can be made from one or more substantially
impermeable materials, such as Dacron.RTM. and PTFE, and can
include ribs that can interface with arterial walls and/or
endograft devices 102 (FIG. 14B). The cuff frame 1468 can have
generally similar characteristics as the integrated frame 104
described above. In other embodiments, the cuff frame 1468 can be
made from individual zigzagged wire hoops like a Z-stent.
[0118] The sleeve 1466 and the cuff frame 1468 can have a
substantially cylindrical shape. In some embodiments, the aortic
cuff 1464 can include two channels to support superior portions 108
of endograft devices 102 (FIG. 14B). For example, the channels can
be formed by stitching the fabric of the sleeve 1466 together to
divide the interior of the aortic cuff 1464. Additionally, the
sleeve 1466 and/or the cuff frame 1468 can have flared proximal and
distal ends to form a stronger seal with adjacent arterial
walls.
[0119] Referring to FIG. 14B, the endograft devices 102 are
deployed within the aortic cuff 1464 after the cuff 1464 has been
at least substantially sealed against the aortic neck 60. The
superior portions 108 can mate with and substantially seal to the
interior of the aortic cuff 1464. The ribs 530 of the cover 106 can
interface with the interior surface of the sleeve 1466 to further
strengthen the seal. Additionally, the integrated frame 104 can
further improve the seal between the endograft devices 102 and the
aortic cuff 1464. For example, the cross-section of the frame 104
in the expanded configuration can be slightly larger than an
interior cross-section of the aortic cuff 1464. As the endograft
devices 102 are deployed within the aortic cuff 1464, the radial
forces from the expansion of the endograft devices 102 can
strengthen the seal therebetween. Additionally, in some
embodiments, the transition portion 324 of the endograft devices
can mate with a complementary taper within the aortic cuff
1464.
[0120] In some embodiments in accordance with the technology, the
aortic cuff 1464 can include alignment aids, such as the alignment
aids 734 described above with reference to FIGS. 7A and 7B, to
facilitate positioning the endograft devices 102 within the aortic
cuff 1464. For example, the aortic cuff 1464 and the outer walls
112 of the endograft devices 102 can include orthogonal alignment
aids that intersect to indicate the endograft devices 102 are
properly aligned within the aortic cuff 1464.
[0121] In additional embodiments, the aortic cuff 1464 can include
anchors, such as the anchors 836 described above with reference to
FIGS. 8A and 8B, to secure the to secure the system 1400 in situ.
For example, the cuff frame 1468 can include anchors that project
radially outwardly and engage adjacent arterial walls.
[0122] FIGS. 15A and 15B are schematic views of a three-part
modular endograft system 1500 ("system 1500") being deployed across
the aneurysm 50 in accordance with an embodiment of the technology.
The system 1500 can include the endograft devices 102 described
with respect to the system 100 and the aortic cuff 1464 described
above with reference to FIGS. 14A and 14B.
[0123] Referring to FIG. 15A, the delivery system 40 can be
inserted using a generally similar method as described above with
reference to FIG. 9A. In the embodiment shown in FIG. 15A, however,
the first catheter 42a and the first guidewire 44a can be inserted
first to deliver the aortic cuff 1464 (FIG. 15B) to the target site
T. The aortic cuff 1464 can be deployed using a generally similar
method as deploying the endograft devices 102 described above with
reference to FIGS. 9A and 9B. The first guidewire 44a can be used
to adjust the aortic cuff 1464 to a desired position in the aortic
neck 60.
[0124] As shown in FIG. 15B, the endograft devices 102 can be
deployed within the aortic cuff 1464. The endograft devices 102 can
be deployed using a substantially similar method as described with
reference to FIG. 9B. For example, the endograft devices 102 can be
delivered through the first and second catheters 42 and positioned
independently within the aortic cuff 1464 using the guidewires 44.
Similar to the method of deploying the superior portions 108
directly against the arterial walls described with reference to
FIGS. 9B and 13B, here the outer walls of the superior portions 108
can at least partially interface with the interior surface of the
aortic cuff 1464 such that the septal walls are aligned with each
other to form the septum 120 (not visible). In some embodiments in
accordance with the technology, the aortic cuff 1464 can include
sections shaped to receive the endograft devices 102 and thereby
ease alignment. In further embodiments, the first endograft device
102a can be anchored or otherwise secured to the aortic cuff 1464
before deployment such that only the second endograft device 102b
must be positioned within the aortic cuff 1464.
[0125] FIG. 16 is a schematic view of a modular endograft system
1600 ("system 1600") being deployed across the aneurysm 50 in
accordance with another embodiment of the technology. The system
1600 can be deployed using generally similar methods as the system
1500 described above with reference to FIGS. 15A and 15B. As shown
in FIG. 16, however, the superior portions 108 project above the
aortic cuff 1464 such that the first end portions 118a provide
additional structure for securing the endograft devices to the
arterial walls of the aorta 52. Additionally, the inferior portions
110 of the endograft devices 102 terminate within the aneurysm 50.
Therefore, the system 1600 further includes limbs (not shown), such
as the limbs 1362 described above with reference to FIGS. 13A-C,
that connect to the inferior portions 110 and extend into the iliac
arteries 56. The catheters 42 can be used to adjust the length of
the limbs to accommodate differing anatomies of the iliac arteries
56 and to maximize the fixation and sealing areas between the limbs
and the arterial walls. Additionally, in some embodiments, the
limbs can intersect (e.g., the limbs 1362 shown in FIG. 13C) to
strengthen the seal at the aortic neck 60 and decrease the
likelihood of endoleaks. Similar to the four-part system 1300
described above, the five-part system 1600 can accommodate
anatomical variations without requiring customized components.
[0126] In the embodiments illustrated in FIGS. 9A, 9B, 11-13C, 15A,
15B and 16, the aneurysm 50 is shown in the infrarenal portion of
the aorta 52 because this is the most common site of an AAA. In
other embodiments in accordance with the technology, the modular
endograft systems 100, 1000, 1300, 1500 and 1600 can be deployed
across aneurysms 50 at different portions of the aorta 52 or in
other vessels altogether. For example, in some embodiments, the
aneurysm 50 can extend from the infrarenal portion of the aorta 52
into one or both of the common iliac arteries 56. The inferior
portions 110 or the limbs 1362 of the systems 100, 1000, 1300, 1500
and 1600 can extend past the diseased, aneurysmal portion of the
iliac arteries 56 without blocking blood flow to the internal iliac
arteries 58. In other embodiments, the systems 100, 1000, 1300,
1500 and 1600 can be deployed across aneurysms 50 located in the
supra renal portion of the aorta 52 with the fenestrations 1038
and/or the first end portions 118a positioned at the entrance of
the renal arteries 54. In further embodiments, the systems
described above can be deployed across aneurysms in other portions
of the vasculature that benefit from the use of a bifurcated,
bi-luminal modular endograft system that can be independently
positioned.
[0127] 4. Methods of Manufacturing
[0128] 4.1 Integrated Frame
[0129] Referring back to FIGS. 4A and 4B, the integrated frame 104
can be made by weaving or braiding one continuous wire 426 in a
pattern along a cylindrical mandrel. In some embodiments, the wire
426 is woven with a one over and one under pattern. In other
embodiments, the wire 426 is woven with a two over and one under
pattern, another integrated pattern, and/or a pattern that varies
over the length of the frame 104. The intersections of the wire 426
can remain unbound to increase flexibility of the frame 104. The
wire 426 can form the loops 428 to change direction and continue
the pattern of intersecting wires 426. As described above, the
number of loops 428 at each end portion 118 and the braid angle
.theta. can be selected based on the diameter of the wire 426 and
the desired properties of the frame 104.
[0130] The wire 426 can be removed from the mandrel after it is
braided into the frame 104 and formed into a desired shape (e.g.,
the endograft devices 102 shown above). The frame 104 can then be
heated to a shape-setting temperature specified for the wire
material (e.g., Nitinol), and subsequently quenched. Optionally,
the frame 104 can be annealed to increase the strength of the frame
104. The mandrel can be cylindrical or have the shape of the frame
104 such that the wire 426 remains on the mandrel during heat
treatment. In further embodiments, the frame 104 can be
manufactured using other suitable methods for shaping resilient
biocompatible materials.
[0131] 4.2 Covers and Coatings
[0132] Referring to FIGS. 5A-C, the cover 106 can be made by
shaping a substantially non-permeable cover material, such as
Dacron.RTM., PTFE, and/or other suitable biocompatible materials.
The cover 106 can be formed by first placing the cover material
over a mandrel. The mandrel can include thin grooves that can
correspond to the desired geometry of the ribs 530 on the cover
106. A wire or thread can be wrapped over the cover material and
into the grooves to corrugate the cover material. The cover
material can then be heated on the mandrel until the ribs 530 are
formed and the cover 106 is substantially non-permeable. In some
embodiments, the superior and inferior termini 531a and 531b of the
cover 106 can be shaped to facilitate attaching the cover 106 to a
frame (e.g. the frame 104 shown in FIGS. 4A and 4B) and prevent the
cover 106 from wrinkling at end portions (e.g., the end portions
118 shown in FIGS. 1A and 1B) during constriction. For example, the
superior and inferior termini 531a and 531b can be zigzagged as
shown in FIGS. 5A and 5B, scalloped, or otherwise shaped to limit
wrinkling of the cover on the frame.
[0133] In other embodiments in accordance with the technology,
coating layers can be used in place of or in conjunction with the
cover 106. FIGS. 17A-E are views of coating layers being applied to
an integrated frame 1704 ("frame 1704") in accordance with
embodiments of the technology. The frame 1704 has generally similar
features as the frame 104 described above. For example, the frame
1704 can be made from the braided wire 426.
[0134] Referring to FIG. 17A, the frame 1704 is positioned over a
mandrel 80 in the expanded configuration. As shown in FIG. 17A, a
first coating layer 1770 can be wrapped onto the frame 1704. The
first coating layer 1770 can be a single or double layer of
unsintered tape that can be approximately 0.0005'' thick and made
from PTFE. In other embodiments, the first coating layer 1770 can
have a different thickness and/or the first coating layer 1770 can
be made from another suitable coating material.
[0135] Once the first coating layer 1770 is applied over the frame
1704, the first coating layer 1770 and the frame 1704 can be heated
on the mandrel 80 in an oven. For example, the first coating layer
1770 and the frame 1704 can be heated for less than thirty minutes
in a 370.degree. C. oven. After heating, the coated frame 1704 is
removed from the mandrel 80 and extended and contracted from the
low-profile configuration to the expanded configuration to ensure
the first coating layer 1770 properly adhered to the frame 1704
during heat treatment.
[0136] As shown in FIG. 17B, a second coating material 1772 is
placed over a narrower, second mandrel 82. The second coating
material 1772 can be extended a distance equivalent to the length
of the frame 1704 in the low-profile configuration. Referring to
FIG. 17C, the second coating material 1772 is contracted to the
length of the frame 1704 in the expanded configuration. This
contraction can form small ribs 1730 in the second coating material
1772. The ribs 1730 can be generally similar to the ribs 530
described above with reference to FIGS. 5A-C, but they are on the
interior of the frame 1704. The ribs 1730 prevent the second
coating material 1772 from wrinkling or bunching when the
subsequently attached frame 1704 flexes or bends and thereby reduce
the likelihood of thrombotic problems within the lumen.
[0137] As shown in FIG. 17D, the coated frame 1704 is then extended
to the low-profile configuration and placed over the extended
second coating material 1772 on the second mandrel 82. Each diamond
opening along the frame 1704 can be spot welded using a welding
device 84. Then, the frame 1704 is removed from the second mandrel
82 and extended and contracted from the low-profile configuration
to the expanded configuration to ensure that the first and second
coating layers 1770 and 1772 have adequately adhered to the frame
1704. Additionally, the proximal and distal ends of the frame 1704
are verified to ensure that the first and second coating layers
1770 and 1772 have properly adhered to the frame 1704. If
necessary, tacking can be performed and the edges can be trimmed to
form a dual coated endograft device 1702 shown in FIG. 17E.
[0138] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the technology.
For example, the embodiments illustrated in FIGS. 1A-16 include
covers 106 that extend over the exterior of the integrated frames
104. However, other embodiments of the technology can include
covers 106 that are attached to the interior of the integrated
frame 104 and/or are formed integrally with the frame 104. Certain
aspects of the new technology described in the context of
particular embodiments may be combined or eliminated in other
embodiments. For example, in the embodiments illustrated above,
each endograft device (e.g., 102, 1002) includes a singular lumen
116. However, the endograft devices can include additional lumens
that transverse, bisect, and/or otherwise communicate with the
lumen 116 to accommodate the vasculature. For example, the
endograft devices can include lumens that extend into the renal
arteries, the internal iliac arteries, and/or other arteries.
Further, while advantages associated with certain embodiments of
the technology have been described in the context of those
embodiments, other embodiments may also exhibit such advantages,
and not all embodiments need necessarily exhibit such advantages to
fall within the scope of the technology. Accordingly, the
disclosure and associated technology can encompass other
embodiments not expressly shown or described herein.
* * * * *