U.S. patent application number 17/403515 was filed with the patent office on 2021-12-02 for sealing apparatus and methods of use.
The applicant listed for this patent is Nellix, Inc.. Invention is credited to Michael A. Evans, Raj P. Ganpath, Steven L. Herbowy, Thomas A. Howell, Amy Lee, Sherwin Llamido, K.T. Venkateswara Rao, Craig Rosenberg, Charles S. Taylor.
Application Number | 20210369438 17/403515 |
Document ID | / |
Family ID | 1000005779569 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210369438 |
Kind Code |
A1 |
Ganpath; Raj P. ; et
al. |
December 2, 2021 |
SEALING APPARATUS AND METHODS OF USE
Abstract
A system for treating an aneurysm comprises at least a first
double-walled filling structure having an outer wall and an inner
wall and the filling structure is adapted to be filled with a
hardenable fluid filling medium so that the outer wall conforms to
the inside surface of the aneurysm and the inner surface forms a
generally tubular lumen to provide blood flow. The first filling
structure comprises a sealing feature which forms a fluid seal
between the filling structure and the aneurysm or an adjacent
endograft when the filling structure is filled with the hardenable
fluid filling medium, thereby minimizing or preventing blood flow
downstream of the seal.
Inventors: |
Ganpath; Raj P.; (Mountain
View, CA) ; Lee; Amy; (Sunnyvale, CA) ;
Rosenberg; Craig; (Palo Alto, CA) ; Llamido;
Sherwin; (Newark, CA) ; Herbowy; Steven L.;
(Palo Alto, CA) ; Evans; Michael A.; (Palo Alto,
CA) ; Howell; Thomas A.; (Palo Alto, CA) ;
Taylor; Charles S.; (San Francisco, CA) ; Rao; K.T.
Venkateswara; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nellix, Inc. |
Irvine |
CA |
US |
|
|
Family ID: |
1000005779569 |
Appl. No.: |
17/403515 |
Filed: |
August 16, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14612048 |
Feb 2, 2015 |
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17403515 |
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12478225 |
Jun 4, 2009 |
8945199 |
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14612048 |
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61058810 |
Jun 4, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/95 20130101; A61F
2250/0003 20130101; A61F 2210/0076 20130101; A61F 2250/0069
20130101; A61F 2/90 20130101; A61F 2002/077 20130101; A61F 2002/068
20130101; A61F 2250/0067 20130101; A61F 2/07 20130101; A61F 2/06
20130101; A61F 2002/065 20130101; A61F 2/954 20130101 |
International
Class: |
A61F 2/06 20060101
A61F002/06; A61F 2/95 20060101 A61F002/95; A61F 2/954 20060101
A61F002/954; A61F 2/07 20060101 A61F002/07 |
Claims
1. A system for treating an aneurysm, said system comprising: at
least a first double-walled filling structure having an outer wall
and an inner wall, wherein the filling structure is adapted to be
filled with a hardenable fluid filling medium so that the outer
wall conforms to the inside surface of the aneurysm and the inner
surface forms a generally tubular lumen to provide blood flow; and
a sealing feature, the sealing feature forming a fluid seal between
the filling structure and the aneurysm or an adjacent endograft
when the filling structure is filled with the hardenable fluid
filling medium, thereby minimizing or preventing blood flow
downstream of the seal.
2. The system of claim 1, wherein the sealing feature is disposed
in a neck of the aneurysm and/or disposed upstream of the
aneurysm.
3. The system of claim 1, wherein the sealing feature comprises an
annular cuff disposed at least partially about the first filling
structure.
4. The system of claim 3, wherein the annular cuff is disposed
about a neck region of the filling structure.
5. The system of claim 3, wherein the sealing feature comprises a
thrombogenic material.
6. The system of claim 5, wherein the thrombogenic material is
selected from the group consisting of polyurethane, polycarbonate,
polyester, ePTFE, polyolefin, parylene, gelatin and silicone.
7. The system of claim 5, wherein the thrombogenic material
comprises a thrombogenic drug.
8. The system of claim 1, wherein the sealing feature comprises a
frame coupled with an inside surface of the filling structure.
9. The system of claim 8, wherein the frame comprises a resilient
frame biased to flex radially outward so as to facilitate outward
expansion of the filling structure during deployment.
10. The system of claim 8, wherein the frame comprises any number
of resilient metals and/or resilient polymers.
11. The system of claim 1, wherein the first filling structure has
a main body with a main body width and the sealing feature
comprises a narrow neck region coupled with the main body, the
narrow neck region having a width less than the main body
width.
12. The system of claim 11, wherein the narrow neck region width is
approximately 2% to approximately 20% of the main body width.
13. The system of claim 1, wherein the sealing feature comprises a
tapered shoulder region on an upper portion of the filling
structure.
14. The system of claim 13, wherein the tapered region flares
inwardly from the upper portion of the first filling structure to a
lower portion of the first filling structure.
15. The system of claim 1, wherein the first filling structure
comprises an upper layer of material and a lower layer of material,
wherein at least a portion of the upper layer is fixedly coupled
with at least a portion of the lower layer of material, wherein the
sealing feature comprises an upper filling region formed by a seal
defining the upper filling region and a lower filling region of the
filling structure, the upper and lower filling regions in fluid
communication with one another.
16. The system of claim 15, wherein the upper filling region holds
a smaller volume of filling medium than the lower filling
region.
17. The system of claim 1, wherein the sealing feature comprises an
arm in fluid communication with the region filled with the
hardenable filling medium.
18. The system of claim 1, wherein the sealing feature comprises a
cape or winged region, the cape or winged region flaring radially
outward from the first double-walled filling structure.
19. The system of claim 1, wherein the sealing feature comprises a
band extending circumferentially around the tubular lumen.
20. The system of claim 1, wherein the sealing feature comprises an
enlarged head region and a tapered lower region of the first
filling structure, the tapered region flaring radially outward as
the distance from the head region increases.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. application
Ser. No. 12/478,225 filed Jun. 4, 2009 (now U.S. Pat. No.
8,945,199), which is a non-provisional of, and claims the benefit
of priority under 35 U.S.C. .sctn. 119(e) of U.S. Provisional
Application No. 61/058,810 filed Jun. 4, 2008; each of which the
entire contents are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates generally to medical systems
and methods for treatment. More particularly, the present invention
relates to apparatus and methods for treating aneurysms.
[0003] Aneurysms are enlargements or "bulges" in blood vessels
which are often prone to rupture and which therefore present a
serious risk to the patient. Aneurysms may occur in any blood
vessel but are of particular concern when they occur in the
cerebral vasculature or the patient's aorta.
[0004] The present invention is particularly concerned with
aneurysms occurring in the aorta, particularly those referred to as
aortic aneurysms. Abdominal aortic aneurysms (AAA's) are classified
based on their location within the aorta as well as their shape and
complexity. Aneurysms which are found below the renal arteries are
referred to as infrarenal abdominal aortic aneurysms. Suprarenal
abdominal aortic aneurysms occur above the renal arteries, while
thoracic aortic aneurysms (TAA's) occur in the ascending,
transverse, or descending part of the upper aorta.
[0005] Infrarenal aneurysms are the most common, representing about
eighty percent (80%) of all aortic aneurysms. Suprarenal aneurysms
are less common, representing about 20% of the aortic aneurysms.
Thoracic aortic aneurysms are the least common and often the most
difficult to treat.
[0006] The most common form of aneurysm is "fusiform," where the
enlargement extends about the entire aortic circumference. Less
commonly, the aneurysms may be characterized by a bulge on one side
of the blood vessel attached at a narrow neck. Thoracic aortic
aneurysms are often dissecting aneurysms caused by hemorrhagic
separation in the aortic wall, usually within the medial layer. The
most common treatment for each of these types and forms of aneurysm
is open surgical repair. Open surgical repair is quite successful
in patients who are otherwise reasonably healthy and free from
significant co-morbidities. Such open surgical procedures may be
problematic, however, since access to the abdominal and thoracic
aortas is difficult to obtain and because the aorta must be clamped
off, placing significant strain on the patient's heart.
[0007] Over the past decade, endoluminal grafts have come into
widespread use for the treatment of aortic aneurysm in patients who
cannot undergo open surgical procedures. In general, endoluminal
repairs access the aneurysm "endoluminally" through either or both
iliac arteries in the groin. The grafts, which typically have been
fabric or membrane tubes supported and attached by various stent
structures, are then implanted, typically requiring several pieces
or modules to be assembled in situ. Successful endoluminal
procedures have a much shorter recovery period than open surgical
procedures.
[0008] Present endoluminal aortic aneurysm repairs, however, suffer
from a number of limitations. For example, a significant number of
endoluminal repair patients experience leakage at the proximal
juncture (attachment point closest to the heart) within two years
of the initial repair procedure. While such leaks can often be
fixed by further endoluminal procedures, the need to have such
follow-up treatments significantly increases cost and is certainly
undesirable for the patient. A less common but more serious problem
has been graft migration. In instances where the graft migrates or
slips from its intended position, open surgical repair is required.
This is a particular problem since the patients receiving the
endoluminal grafts are often those who are not considered to be
good surgical candidates.
[0009] Further shortcomings of the present endoluminal graft
systems relate to both deployment and configuration. For example,
many of the commercially available endovascular systems are too
large (above 12F) for percutaneous introduction. Moreover, current
devices often have an annular support frame that is stiff and
difficult to deliver as well as unsuitable for treating many
geometrically complex aneurysms, particularly infrarenal aneurysms
with little space between the renal arteries and the upper end of
the aneurysm, referred to as short-neck or no-neck aneurysms.
Aneurysms having torturous geometries, are also difficult to
treat.
[0010] In order to overcome some of the aforementioned challenges,
the use of endograft systems having a scaffold structure and a
filling structure has been proposed, such as in U.S. patent
application Ser. No. 11/413,460 (Attorney Docket No.
025925-001610US) filed Apr. 28, 2006, the entire contents of which
are incorporated herein by reference. These systems utilize a
filling structure to help seal off and fill the aneurismal sac
while creating a lumen for blood to traverse the aneurysm. Several
references disclosing filling structures and which are the subject
of the commonly owned, copending applications are described below.
These systems may also include a stent-like scaffold which helps
support the filling structure thereby further defining the lumen
for blood flow. The filling structure may require a pre-filling
step to help unfurl the filling structure prior to filling it with
the hardenable filling material and an expandable balloon often is
used to help support the endograft during filling and during
hardening in order to ensure proper formation of a lumen for blood
flow. Because the filling material may take some time to harden,
the expanded balloon can occlude flow for an undesirable time.
Additionally, even after filling and hardening of filling material
in the filling structure, the aneurismal sac may not be completely
sealed off and blood can still flow into the sac. For these reasons
it would be desirable to provide alternative apparatus and methods
that create a better seal between the aneurismal sac and the
endograft. It would also be desirable to provide apparatus and
methods that help filling structures expand and conform to the
aneurysm anatomy. Moreover, it would also be desirable for sealing
apparatus and methods to minimize or eliminate the need for a
separate unfurling step as well as minimizing the need to use an
inflated balloon for support during filling and hardening that can
obstruct blood flow. It would also be desirable that the
alternative apparatus have a low profile for ease of delivery and
percutaneous introduction as well as flexibility to allow
advancement of the device through torturous vessels such as the
iliac arteries. It would further be desirable that such devices can
accommodate a variety of different vessel and aneurysm anatomies.
At least some of these objectives will be met by the inventions
described hereinbelow.
2. Description of the Background Art
[0011] U.S. Patent Publication No. 2006/0025853 describes a
double-walled filling structure for treating aortic and other
aneurysms. Copending, commonly owned U.S. Patent Publication No.
2006/0212112, describes the use of liners and extenders to anchor
and seal such double-walled filling structures within the aorta.
The full disclosures of both these publications are incorporated
herein by reference. PCT Publication No. WO 01/21108 describes
expandable implants attached to a central graft for filling aortic
aneurysms. See also U.S. Pat. Nos. 5,330,528; 5,534,024; 5,843,160;
6,168,592; 6,190,402; 6,312,462; 6,312,463; U.S. Patent
Publications 2002/0045848; 2003/0014075; 2004/0204755;
2005/0004660; and PCT Publication No. WO 02/102282.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention provides apparatus and methods for the
treatment of aneurysms, particularly aortic aneurysms including
both abdominal aortic aneurysms (AAA) and thoracic aortic aneurysms
(TAA).
[0013] In a first aspect of the present invention, a system for
treating an aneurysm comprises at least a first double-walled
filling structure having an outer wall and an inner wall and the
filling structure is adapted to be filled with a hardenable fluid
filling medium so that the outer wall conforms to the inside
surface of the aneurysm and the inner surface forms a generally
tubular lumen to provide blood flow. The first filling structure
comprises a sealing feature which forms a fluid seal between the
filling structure and the aneurysm or an adjacent endograft when
the filling structure is filled with the hardenable fluid filling
medium. This minimizes or prevents blood flow downstream of the
seal.
[0014] The walls of the filling structure may comprise ePTFE and
the seal may be disposed upstream of the aneurysm, for example in
the aneurysm neck. Sometimes the walls of the filling structure may
be coated with another polymer such as polyurethane. The tubular
lumen may have a substantially circular cross-section and the first
filling structure may comprise an elliptical cross-section when the
filling structure is filled with the hardenable filling medium. The
edges of the first filling structure may be sealed together so that
the filling structure can withstand a filling pressure of up to 300
mm Hg above a patient's normal systolic blood pressure without
bursting. Some systems may also comprise a thrombogenic material
such as polyurethane, polycarbonate, polyester, ePTFE, polyolefin,
parylene, gelatin and silicone. The thrombogenic material may be
coupled with an outer surface of the first filling structure and it
may be formed into one of sutures, felts, velours, weaves, knits,
hydrogels, foams, coils, sheets and combinations thereof. The
thrombogenic material may also comprise a thrombogenic drug.
[0015] In some embodiments the first filling structure may include
a main body having a main body width and the sealing feature may
comprise a narrow neck region that is coupled with the main body.
The narrow neck region may have a width that is less than the main
body width. The width of the narrow neck region may be
approximately 2% to approximately 20% of the main body width.
Sometimes the sealing feature may include a flat shoulder on an
upper portion of the filling structure. Other embodiments may have
a sealing feature which includes a tapered shoulder region on an
upper portion of the filling structure.
[0016] Still, in other embodiments the first filling structure may
comprise an upper layer of material having an upper layer width and
a lower layer of material having a lower layer width that is wider
than the upper layer width. The upper and lower layers are fixedly
coupled together so as to form the sealing feature which comprises
a substantially flat upper outer surface and an arcuate lower outer
surface when the first filling structure is filled with hardenable
filling medium. The first filling structure may comprise a D-shaped
cross-section when filled with hardenable filling medium.
[0017] The sealing feature may comprise a tapered region in the
tubular lumen with the taper disposed near an upper portion of the
first filling structure. The tapered region may flare inwardly from
the upper portion of the first filling structure to a lower portion
of the first filling structure. In other embodiments, the first
filling structure may comprise an upper layer of material and a
lower layer of material, wherein at least a portion of the upper
layer is fixedly coupled with at least a portion of the lower layer
of material which forms the sealing feature. In this case, the
sealing feature comprises an upper filling region and a lower
filling region formed by the seal with the two filling regions in
fluid communication with one another. The upper filling region may
hold a smaller volume of filling medium than the lower filling
region and the seal may be formed along a line. The line may extend
from an outer edge of the first filling structure inward towards
the tubular lumen.
[0018] In other embodiments, the system may further comprise a
second double-walled filling structure having an outer wall and an
inner wall, wherein the second filling structure is adapted to be
filled with a hardenable fluid filling medium so that the outer
wall conforms to the inside surface of the aneurysm and the inner
surface forms a generally tubular lumen to provide blood flow. The
second filling structure may comprise a sealing feature which forms
a fluid seal between the filling structure and the aneurysm or an
adjacent endograft when the second filling structure is filled with
the hardenable fluid filling medium. This minimizes or prevents
blood flow downstream of the seal. The sealing feature of the first
double-walled filling structure may comprise an outer surface
having a first shape and the sealing feature of the second
double-walled filling structure may comprise an outer surface
having a second shape. The first and second shapes may be
complementary to one another. In some embodiments, the first and
second shapes comprise complementary tapers.
[0019] In still other embodiments, the sealing feature may comprise
a foam filled region of the first filling structure and the foam
filled region may be discrete from the remainder of the first
filling structure. The discrete foam filled region may be fluidly
isolated from the region filled with the hardenable filling medium.
In other embodiments, the sealing feature may comprise an arm in
fluid communication with the region filled with the hardenable
filling medium. Alternatively, the sealing feature may comprise a
slot that is substantially transverse to a longitudinal axis of the
first double-walled filling structure. The slot may at least
partially bisect the first double-walled filling structure into two
fillable sections. The foam may be substituted for any other
material that provides the desired compliance to the foam filled
region, such as gels, suture material, etc.
[0020] Some embodiments may have a sealing feature which comprises
a winged region that flares radially outward from the first
double-walled filling structure. The winged region may comprise a
tapered shoulder on an outer surface of the first double-walled
filling structure. The sealing feature may further comprise a
tapered lower region in the tubular lumen which flares radially
outward from an upper part to a lower part of the first filling
structure. Sometimes the sealing feature may also comprise a
restraining element that is disposed at least partially around the
tubular lumen. The restraining element may be adapted to restrict
radial expansion of the tubular lumen to a predetermined size or
shape. Sometimes the restraining element comprises a band extending
circumferentially around the tubular lumen.
[0021] The sealing feature may comprise an enlarged head region and
a tapered lower region on the first filling structure. The tapered
region flares radially outward as the distance from the head region
increases. The sealing feature may comprise a lower tubular cuff
region coupled with the first filling structure and a winged
portion on the first filling structure. The sealing feature may
also include an upper tubular cuff region coupled with the first
filling structure. Sometimes the sealing feature includes a
skeletal frame disposed in between the inner and outer walls of the
first filling structure and the inner wall radially expands inward
as the first filling structure is filled with hardenable filling
material. Alternatively, the first filling structure may be
disposed on the inside surface of a radially expandable scaffold
and the sealing feature may comprise a portion of the inner wall
that is adapted to radially expand inward to engage and seal
against an adjacent endograft.
[0022] The sealing feature may comprise an angled bottom edge on
the first filling structure. In some embodiments, the filling
structure may comprise a straight top edge and the angled bottom
edge forms an acute angle relative to the top edge. In other
embodiments, the sealing feature comprises a discrete filling
compartment separate from the filling space of the first
double-walled filling structure and fluidly uncoupled thereto. The
discrete filling compartment may have a rectangular shaped region
and the hardenable filling medium may surround the discrete filling
compartment. An elongate flexible filling tube may be slidably
engaged with the discrete filling compartment and the filling
space.
[0023] In other embodiments, the sealing feature may comprise a
shoulder that is disposed on a lower portion of the first filling
structure. The first filling structure may have a main body width
and the shoulder may have a shoulder width that is less than the
main body width. The sealing feature may comprise an undercut
region in the first filling structure that is adapted to expand
outwardly when the first filling structure is filled with
hardenable filling material.
[0024] The sealing feature may include a plurality of filaments
coupled with the first filling structure and extending axially
therefrom. These filaments may include a thrombogenic material. The
thrombogenic material may also be a cape that is disposed at least
partially over the first filling structure and coupled thereto. The
sealing feature could also be a thrombogenic annular ring that is
disposed at least partially around the first filling structure.
Other sealing features may include a plurality of flanges that are
coupled with the first filling structure. The flanges may have a
width that progressively decreases relative to an adjacent flange.
Also, the flanges may have a thickness that progressively decreases
relative to an adjacent flange.
[0025] In still other embodiments the sealing feature may comprise
a skeletal frame that is coupled with the first filling structure.
The skeletal frame may comprise a plurality of self-expanding
struts that are adapted to radially expand outward along with the
outer wall of the first filling structure. The skeletal frame may
comprise a wire-like helically shaped filament made from a material
such as nitinol.
[0026] The scaling feature may also comprise an upper and a lower
tubular shaped cuff that is coupled with the first filling
structure. At least one of the upper or lower cuffs may comprise a
reinforced region. The reinforced region may comprise a wire-like
frame and sometimes the upper and lower reinforced cuffs may be
coupled together with a plurality of struts.
[0027] In still other embodiments, the sealing feature may comprise
a pair of fillable legs that are coupled with the first filling
structure. The sealing feature may comprise a first region of the
first filling structure having a first compliance and a second
region of the first filling structure having a second compliance
different than the first compliance. One of these regions may be
embossed and another region may remain unembossed.
[0028] The system may further comprise a delivery catheter that has
an expandable tubular support such as a balloon, which can be
positioned within the tubular lumen to carry the double-walled
filling structure. The system may also comprise a scaffold that is
radially expandable from a collapsed configuration to an expanded
configuration. A filling port that is fluidly coupled with the
filling structure may also be included in the system. The filling
port may be an elastomeric plug, and may be adapted to receive the
hardenable filling medium and also provides a seal to prevent
leakage thereof. The filling port may be substantially contained
within the inner lumen of the filling structure when the filling
structure is filled with the hardenable filling medium.
[0029] In another embodiment of the invention, a system for
treating an aneurysm comprises at least a first double-walled
filling structure having an outer wall and an inner wall. The
filling structure is adapted to be filled with a hardenable fluid
filling medium so that the outer wall conforms to the inside
surface of the aneurysm and the inner surface forms a generally
tubular lumen to provide blood flow. The system also includes a
filling port that is substantially contained within the generally
tubular lumen of the filling structure when the filling structure
is filled with the hardenable fluid filling medium. A first end of
the generally tubular lumen may comprise an invaginated tapered
portion that flares radially outward. A second end of the tubular
lumen may comprise an invaginated tapered portion that flares
radially outward. The second end may be opposite of the first end.
The first filling structure may comprise a sealing feature that
forms a fluid seal between the filling structure and the aneurysm
or an adjacent endograft when the filling structure is filled with
the hardenable fluid filling medium. This reduces or prevents blood
flow downstream of the seal. The sealing feature may comprise a
tapered shoulder region on at least one end of the filling
structure. The outer wall of the filling structure may be
invaginated into the filling structure thereby forming a convex
exterior surface on one end of the filling structure when the
filling structure is filled with the hardenable fluid filling
medium. A convex exterior surface may also be similarly formed on a
second end of the filling structure opposite the first end. Either
convex exterior surface may taper radially inwardly to merge with
the tubular lumen.
[0030] These and other embodiments are described in further detail
in the following description related to the appended drawing
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 illustrates the anatomy of an infrarenal abdominal
aortic aneurysm.
[0032] FIG. 2 illustrates a single prosthesis system comprising a
filling structure mounted over a delivery catheter.
[0033] FIG. 3 illustrates a pair of prostheses for delivery to an
aneurysm, where each prosthesis comprises a filling structure
mounted on a delivery catheter.
[0034] FIGS. 4A-4F illustrate use of the filling structures of the
prosthesis system in FIG. 3 for treating an aortic aneurysm.
[0035] FIGS. 4G-4H illustrate the placement of scaffolds into the
adjacent tubular lumens of the two filling structures of the
prostheses of FIGS. 4A-4F.
[0036] FIGS. 4H-1 and 4H-2 are cross-sectional views taken along
line 4H1-4H1 or 4H2-4H2 in FIG. 4H.
[0037] FIGS. 5A-5B illustrate one embodiment of a double-walled
filling structure.
[0038] FIGS. 5C-5E illustrate an exemplary method of fabricating
the filling structure in FIGS. 5A-5B.
[0039] FIG. 5F illustrates a filling port.
[0040] FIGS. 6A-18 illustrate alternative embodiments of a
double-walled filling structure.
[0041] FIGS. 19A-20 illustrate filling structures with regions of
different compliance.
[0042] FIG. 21 illustrates a system for treating an aneurysm having
three endografts.
[0043] FIGS. 22-26B illustrate various embodiments of filling
structures that may be used in the endograft system of FIG. 21.
[0044] FIGS. 27-29 illustrate various thrombogenic features used to
help create a seal.
[0045] FIGS. 30A-30C illustrate several embodiments of resilient
frames coupled with the filling structure.
[0046] FIGS. 31A-32D illustrate various reinforced regions and
patterns that may be used on a filling structure.
[0047] FIGS. 33A-33B illustrate another embodiment of a filling
structure.
[0048] FIGS. 34A-34D illustrate the use of multiple filling
structures stacked together.
[0049] FIGS. 35A-35B illustrate an alternative embodiment of a
double-walled filling structure.
DETAILED DESCRIPTION OF THE INVENTION
[0050] Referring now to FIG. 1, the anatomy of an infrarenal
abdominal aortic aneurysm comprises the thoracic aorta (TA) having
renal arteries (RA) at its distal end above the iliac arteries
(IA). The abdominal aortic aneurysm (AAA) typically forms between
the renal arteries (RA) and the iliac arteries (IA) and may have
regions of mural thrombus (T) over portions of its inner surface
(S).
[0051] FIG. 2 illustrates a single endograft system comprising a
filling structure mounted over a delivery catheter. A system 10
constructed in accordance with the principles of the present
invention for delivering a double-walled filling structure 12 to an
aneurysm includes the filling structure and a delivery catheter 14
having an expandable element 16, typically an inflatable balloon,
at its distal end. The catheter 14 will comprise a guidewire lumen
18, a balloon inflation lumen (not illustrated) or other structure
for expanding other expandable components, and a filling tube 20
for delivering a filling medium or material to an internal space 22
of the double-walled filling structure 12. The internal space 22 is
defined between an outer wall 24 and inner wall 26 of the filling
structure. Upon inflation with the filling material or medium, the
outer wall will expand radially outwardly, as shown in broken line,
as will the inner wall 26, also shown in broken line. Expansion of
the inner wall 26 defines an internal lumen 28. The expandable
balloon or other structure 16 will be expandable to support an
inner surface of the lumen 28, as also in broken line in FIG. 1. A
single endograft system such as that seen in FIG. 1 may be used to
treat an aneurysm as disclosed in U.S. patent application Ser. No.
11/413,460 (Attorney Docket No. 025925-001610US), the entire
contents of which are incorporate herein by reference.
[0052] In preferred embodiments, a system comprising two endografts
may be used to treat an aneurysm, such as the system seen in FIG.
3. A system comprising such a pair of filling structures includes a
first filling structure 112 and a second filling structure 212.
Each of the filling structures 112 and 212 are mounted on delivery
catheters 114 and 214, respectively. The components of the filling
structures 112 and 212 and delivery catheters 114 and 214 are
generally the same as those described previously with respect to
the single filling structure system 10 of FIG. 2. Corresponding
parts of each of the fillings systems 112 and 212 will be given
identical numbers with either the 100 base number or 200 base
number. A principal difference between the filling structures 112
and 212, on the one hand, and the filling structure 12 of FIG. 2 is
that the pair of filling structures will generally have asymmetric
configurations which are meant to be positioned adjacent to each
other within the aneurismal space and to jointly fill that space,
as will be described in greater detail below.
[0053] In treating an infrarenal abdominal aortic aneurysm using
the pair of filling structures 112 and 212 illustrated in FIG. 3, a
pair of guidewires (GW) will first be introduced, one from each of
the iliac arteries (IA), as seen in FIG. 4A. The first delivery
catheter 114 will then be positioned over one of the guidewires to
position the double-walled filling structure 112 across the aortic
aneurysm (AAA), as illustrated in FIG. 4B. The second delivery
catheter 214 is then delivered over the other guidewire (GW) to
position the second filling structure 212 adjacent to the first
structure 112 within the aneurysm (AAA), as illustrated in FIG. 4C.
Typically, one of the filling structures and associated balloons
will be expanded first, followed by the other of the filling
structures and balloon, as illustrated in FIG. 4D where the filling
structure 112 and balloon 116 are inflated to fill generally half
of the aneurismal volume, as illustrated in FIG. 4D. Filling can
generally be carried out as described for one filling structure in
U.S. patent application Ser. No. 11/413,460 (Attorney Docket No.
025925-001610US) which has been previously incorporated herein by
reference, except of course that the filling structure 112 will be
expanded to occupy only about one-half of the aneurismal volume.
After the first filling structure 112 has been filled, the second
filling structure 212 may be filled, as illustrated in FIG. 4E. In
other protocols the two filling structures may be filled
simultaneously. The upper ends of the balloons 116 and 216 will
conform the tubular lumens of the filling structures against the
walls of the aorta as well as against each other, while the lower
ends of the balloons 116 and 216 will conform the tubular lumens
into the respective iliac (IA).
[0054] After filling the filling structures 112 and 212 as
illustrated in FIG. 4E, the filling materials or medium will be
cured or otherwise hardened, and the delivery catheters 114 and
removed, respectively. The hardened filling structures will then
provide a pair of tubular lumens opening from the aorta beneath the
renal arteries to the right and left iliac arteries, as shown in
broken line in FIG. 4F. The ability of the filling structures 112
and 212 to conform to the inner surface (S) of the aneurysm, as
shown in FIG. 4F, helps the structures to remain immobilized within
the aneurysm with little or no migration. Immobilization of the
filling structures 112 and 114 may be further enhanced by providing
any of the surface features described in U.S. patent application
Ser. No. 11/413,460 (Attorney Docket No. 025925-001610US),
previously incorporated herein by reference.
[0055] As with the single filling structure embodiments, the double
filling structure embodiments will include at least one separate
scaffold deployed within each of the tubular blood flow lumens. The
scaffolds will generally be stent-like or graft-like vascular
structures and will be deployed within the tubular lumens using
balloon or other expansion catheters (in the case of malleable or
balloon-expandable scaffolds) or using constraining sheaths (in the
case of self-expanding scaffolds).
[0056] Referring in particular to FIG. 4G, the first scaffold 250
may be placed in the tubular lumen of the first filling structure
112 while a second scaffold 252 may be placed in the tubular lumen
of the second filling structure 212. As illustrated, the scaffolds
are stent-like structures which extend into the iliac arteries IA
at the lower end of the filling structures. The scaffolds 250, 252
may also be deployed simultaneously with the filling structures
112, 212.
[0057] Referring now to FIG. 4H, first and second scaffolds 254 and
256 may extend upwardly on the aortic side of the first and second
filling structures 112 and 212. When the separate stent or other
scaffold structures extend into the thoracic aorta TA, it will
usually be desirable that they be expanded so that they conform to
each other along a plane or region of contact. For example, as
shown in FIG. 4H-1, the upper ends of the scaffolds 254 and 256 may
be formed preferentially to have D-shaped cross-sections when
expanded. Thus, flat faces 258 and 260 will engage each other with
the remaining portion of the stent conforming to the inner wall of
the aorta. In this way, most of the cross-sectional area of the
aorta will be covered with the stent, thus enhancing blood flow
through the filling structures. Alternatively, as shown in FIG.
4H-2, the upper regions of the scaffolds 254 and 256 may be cut or
otherwise modified to form open C-shaped cross-sections. In such
cases, the expanded scaffolds can be arranged so that the C-shaped
regions engage each other to form a continuous ring structure about
the inner wall of the aorta. The open C-shaped regions will
transition into a tubular region as the scaffolds enter the tubular
lumens of the filling structures 112 and 212. In either of these
embodiments, the scaffolds 254 and 256 may be partially or fully
covered with a membrane or graft material and such coverings may
extend partially or fully over the portion of the scaffold that
extends into the adjacent blood vessel.
[0058] Various modifications of the protocols described above will
be within the scope of the present invention. For example, while
the scaffolds have been shown as being delivered after deployment
of the filling structure(s), it will also be possible to deliver
the scaffolds simultaneously with or prior to deployment of the
filling structures. Moreover, the scaffolds could be delivered on
the same delivery catheter(s) used to deliver and/or shape the
filling structures. The scaffolds could then be expanded at the
same time as filling the filling structure or even prior to filling
the filling structure. Additional details on these embodiments are
disclosed in U.S. patent application Ser. No. 11/413,460 (Attorney
Docket No. 025925-001610US), previously incorporated herein by
reference.
[0059] The filling structure used in FIGS. 4A-4H are more fully
described in FIGS. 5A-5E. FIG. 5A illustrates the double-walled
filling structure separated from the delivery catheter and
scaffold. In FIG. 5A, the outer wall 502 is the portion of the
filling structure which expands into engagement with the aneurysm
wall when filled with filling material and inner wall forms lumen
504 in which blood traverses the aneurysm. A filling tab FT is
coupled with the filling structure and acts as a valve to allow
filling of the filling structure. FIG. 5B shows an end view of the
filling structure with an oval or elliptical-shaped outer wall 502
and a round inner lumen 504. The walls of the filling structure are
preferably made from ePTFE with a polyurethane inner lining which
prevents extravasation of the filling material through the pores of
the ePTFE. Other polymers or fabrics may also be used such as
Dacron polyester. Any of the filling structure embodiments in this
disclosure may use these materials.
[0060] The filling structure of FIGS. 5A-5B may be fabricated from
two sheets of polymer as seen in FIGS. 5C and 5D. In FIG. 5C, an
upper sheet is die cut from ePTFE and has an upper flat pan section
508a and a lower handle section 510a. In FIG. 5D, a second sheet is
also die cut from ePTFE and also has an upper pan section 508b and
a lower handle section 510b. The upper and lower sheets are
substantially the same size. The two sheets are then placed on top
of one another and the edges are then sealed together around most
of the perimeter, as seen by seam 512 in FIG. 5E. The lower handle
section is then invaginated and pulled through the flat pan section
as indicated by arrow 514. The unsealed portions are then sealed.
Sealing may be accomplished using a hot wire, impulse sealing. RF
heat sealing or laser welding. This forms the inner lumen of the
filling structure, as indicated by dotted lines in FIG. 5A. A
filling tube 506 may be used to allow filling of the filling
structure as seen in FIG. 5A or a filling port 516 may be used as
illustrated in FIG. 5F. The filling port 516 may be an elastomeric
plug such as latex or polymer that allows a needle or other tube to
penetrate the filling port and that self seals when the needle or
tube is withdrawn. This method of fabrication generally applies to
any of the embodiments disclosed herein. Other fabrication methods
include inverting a tubular extrusion and sealing the ends which is
advantageous since it minimizes seams. Also, in some embodiments,
the filling structure may be composed of separate components that
are joined together. For example, the tubular lumen section may be
formed separately and then coupled with the main body of the
filling portion.
[0061] As previously discussed, these filling structures show
promise in the treatment of aneurysms as they help seal the
aneurysm and also they help fix an endograft system in place
thereby minimizing the possibility of migration. However, the
filling structures can still leak. Therefore, other filling
structure configurations and features are disclosed herein which
may provide better sealing.
[0062] In FIG. 6A, the filling structure has an outer wall W and an
inner wall forms the lumen L. This embodiment also includes a flat
shoulder 608 and a narrow neck region 610 which may accommodate
aneurysm anatomies better and therefore provide better sealing.
FIG. 6B shows and end view of the filling structure in FIG. 6A. The
neck region may have a width any size, but in preferred
embodiments, the width of the neck region 610 is approximately 2%
to approximately 20% of the filling structure width measured at
it's widest point. FIGS. 7A-7B show another embodiment of a filling
structure. In FIG. 7A, a double-walled filling structure includes a
tapered upper portion 620 which provides a flat surface against
which a seal may be made. FIG. 7B shows an end view of the filling
structure seen in FIG. 7A which has a generally oval shape when
filled with filling material and the lumen L is generally
round.
[0063] FIGS. 8A-8B show another embodiment of a filling structure.
In FIG. 8A, a first layer of material is welded to a second layer
of material that is wider than the first. This results in one side
of the filling structure having more material than the opposite
side. Therefore, one side of the outer wall W will have a
substantially flat section 626 and the opposite side will be
arcuate 630 with a straight section 628 joining the two sections
together. The end view of the filling structure will be D-shaped as
seen in FIG. 8B.
[0064] Still another filling structure embodiment is seen in FIGS.
9A-9B. In FIG. 9A the inner wall of the filling structure forms
lumen L. Lumen L includes a straight tubular section and a tapered
portion 640 near an upper portion of the filling structure. The
tapered portion 640 flares radially outward. FIG. 9B shows an end
view of the filling structure seen in FIG. 9A. In FIG. 9B, outer
wall W forms a round or oval shape and lumen L is generally
round.
[0065] FIGS. 10A-10B illustrate the use of additional seals in the
filling structure to define additional filling regions. In FIG.
10A, the two layers of material are sealed together along a line
644 forming a pocket 646 which is fillable with the hardenable
filling material. In this embodiment, the seal 644 is seen running
across both the left and right halves of the filling structure and
in a direction generally transverse to the longitudinal axis of the
filling structure. The length of the scal, number of seals and
angle of the seal relative to the filling structure longitudinal
axis may be varied. Also, in this embodiment, the pocket 646 is
still in fluid communication with the main fillable region of the
filling structure. FIG. 10B illustrates an end view of the filling
structure seen in FIG. 10A.
[0066] In FIG. 11, two filling structures are used to complement
one another and help for a seal. In FIG. 11, a first filling
structure has an outer wall with a taper 652 and a generally
tubular lumen L. A second filling structure has an outer wall W
with a taper 654 that is complementary to the first taper 652,
therefore the two filling structures will engage one another where
the two tapers meet. Because the two tapers are complementary with
one another, they will be flush against one another. The use of two
filling structures may be used when two endograft systems are
deployed in an aneurysm, such as in FIGS. 4A-4G above.
[0067] FIG. 12 shows a foam filled region 660 near an upper portion
of the filling structure. The foam filled region 660 is separated
from the remainder of the fillable space by a seal 662 which may be
made by heat sealing, bonding or other attachment methods known in
the art. The foam filled region provides a compliant end that
allows the filling structure to conform to the aneurysm anatomy
thereby helping create a seal.
[0068] FIG. 13 shows an alternative embodiment of a filling
structure having a flexible arm coupled with the filling structure.
A slot 668 separates the arm 666 from the main body of the filling
structure, although a channel 670 fluidly couples the arm 666 with
the main body of the filling structure. Therefore, as the filling
structure is filled with hardenable medium, the arm 666 will also
fill up. The arm is flexible and therefore will flex and fit into
various aneurysms spaces thereby creating the seal.
[0069] FIG. 14 illustrates an angled filling structure. In FIG. 14,
a bottom edge 680 of the filling structure is angled relative to
the top edge 682. In this embodiment, the bottom edge forms an
acute angle relative to the top edge 682 although the angle may be
adjusted to accommodate different aneurysm anatomies.
[0070] FIG. 15 illustrates the use of two filling regions in the
filling structure. In FIG. 15, the filling structure has a main
filling region 688 and a separate, discrete filling region near a
top of the filling structure. A filling tab FT is fluidly coupled
with both fillable regions 686, 688, thus a filling tube may be
slidably received by the upper filling region 686. After this
region is filled, the filling tube is retracted out of the upper
filling tab and into the lower filling tab so that the main filling
region can then be filled. The upper filling region may be created
by scaling a region off from the main body of the filling
structure. This two stage filling process may allow the filling
structure to create a better seal with the aneurysm.
[0071] FIG. 16 illustrates still another embodiment of a
double-walled filling structure. In FIG. 16, the filling structure
comprises a wide main body section 704 and a narrow neck region 702
on an upper end of the filling structure. A lower end of the
filling structure has an annular flange 706 that has a width less
than the main body section 704. This helps prevent or minimize
pinching in the lower end of the filling structure and may help the
filling structure accommodate various aneurysm anatomies.
[0072] FIG. 17 illustrates another embodiment of a double-walled
filling structure. In FIG. 17, the filling structure has a wide
main body section 728, a shoulder region 722 and a narrow neck
region 720. Additionally, a concave bottom region 724 of the
filling structure may expand outward when filled as indicated by
dotted line 726.
[0073] FIG. 18 shows another filling structure embodiment having
multiple annular flanges. In FIG. 18, the filling structure
comprises a wide main body section 742 and a tapered lower region
744. The main body section has a tapered shoulder region 752 which
transitions into a region of multiple annular flanges. A first
annular flange 746 is followed by two additional annular flanges
748, 750. The width and thickness of each flange progressively
decreases such that flange 746 is the widest and thickest while
flange 750 is the thinnest. The multiple flanges help create a seal
at one end of the filling structure by minimizing pinch points.
[0074] FIGS. 19A-19B illustrate how the compliance of the filling
structure may be modified to affect how it expands. In FIG. 19A,
the wall forming the inner lumen L may be made from a material
having one compliance and the wall forming the outer wall W may be
made from a material having greater compliance. Thus, when the
filling structure is filled with the hardenable filling material,
the outer wall will preferentially radially expand outward before
the inner lumen wall. Thus, the lumen will remain relatively
unchanged during filling and the outer wall will conform to the
aneurysm. In FIG. 19B, the upper half of the outer wall of the
filling structure is fabricated from a material more compliant
relative to the lower half of the filling structure. Thus, the
upper outer half 762 will radially expand more than the lower half
during filling. One will appreciate that compliance of the filling
structure walls may be varied to obtain desired expansion
characteristics. Instead of using different materials to control
filling structure compliance, surface modification may be used to
alter a material's compliance. For example, in FIG. 20, an upper
portion 770 of a filling structure has been embossed while a lower
portion 772 remains unembossed. Embossing the material alters
material characteristics such as compliance. In the case of
expanded polytetrafluorinated ethylene (ePTFE), embossing increases
material compliance so region 770 will have a greater compliance
and expand more than the unembossed region 772.
[0075] While most of the filling structure embodiments disclosed
above are described as being used when two endograft systems are
deployed (e.g. FIG. 3) to treat an aneurysm, the embodiments
described above may also be used in other endograft systems as
well. For example, in some cases, it may be desirable to use a
three piece endograft system to treat an aneurysm, such as in FIG.
21. In FIG. 21, a first docking scaffold 790 is deployed in the
neck of the aneurysm AAA and an optional filling structure 792 may
be used to seal the neck region off from blood flow. Two leg
extension scaffolds 796 and 798 are then advanced an expanded at
least partially within the docking scaffold 790. The leg scaffolds
796 and 798 may also have optional filling structures 794, 799
which may be expanded with hardenable filling material to fill the
aneurismal space. Additional details on the three piece endograft
system is disclosed in U.S. Provisional Patent Application No.
61/052,059 (Attorney Docket No. 025925-002800US), the entire
contents of which are incorporated herein by reference. The filling
structures previously described may therefore be used in
conjunction with the docking scaffold or either leg extension
scaffold. Additional filling structure embodiments which may be
used in the three piece docking system or the two piece system
previously described are discussed in greater detail below.
[0076] FIG. 22 shows an embodiment of a filling structure having
two legs 802, 804. In FIG. 22, the main body 806 of the filing
structure may be coupled with the docking scaffold to help seal at
the neck of the aneurysm. Two leg regions 802, 804 help to seal
around the leg extension scaffolds that are received by the docking
scaffold. FIG. 23 shows another embodiment of a filling structure
which may be used in conjunction with a docking scaffold. In FIG.
23, the filling structure has a main body region 812 with an
enlarged head region 810 and a tapered lower region 814. The
enlarged head region 810 and the tapered lower region help seal the
docking scaffold around the neck of the aneurysm. FIGS. 24A-24C
illustrate other embodiments which may be used with the docking
scaffold. For example, in FIG. 24A a filling structure has a main
body portion 824 with a tapered shoulder 822 and a narrow neck
region 820. The inner lumen L in the embodiment of FIG. 24A is
substantially tubular and has a constant diameter. In FIG. 24B, the
filling structure has generally the same shape as in FIG. 24A
except in this embodiment, the lumen L is tapered outwardly 826
near a lower end of the filling structure. The embodiment of FIG.
24C is also similar to that of FIG. 24A but also has a modified
lumen L. In FIG. 24C, the filling structure lumen L has a lower
portion that is constrained 828 in order to limit its expansion.
The constraint 828 may be a band or corset coupled with the inner
wall, or a low compliance material may be used in that region to
limit expansion of the lumen L.
[0077] FIGS. 25A-25C illustrate still other embodiments of filling
structures which may be used with the docking scaffold. In FIG.
25A, the filling structure comprises a main body section 840 with a
tapered shoulder 842 that transitions to a narrow neck region 844.
FIG. 25B is similar to the embodiment of FIG. 25A except that both
ends of the filling structure have a narrow neck region 844, 848
coupled with the main body of the filling structure. A flat or
tapered shoulder region 846 may couple the narrow neck region 844,
848 with the main body of the filling structure. FIG. 25C shows
another variation of the embodiment in FIG. 25A. In FIG. 25C, the
filling structure has narrow neck regions 844, 848 coupled to the
main body of the filling structure. A tapered shoulder region 842
couples the upper narrow neck region 844 with the filling structure
main body and a flat lower shoulder 849 couples the lower narrow
neck region 848 with the main body of the filling structure.
[0078] The previous embodiments generally are disposed over a
scaffold structure and radially expand outward to seal against the
aneurysm wall. In FIGS. 26A-26B, a filling structure is used to
fill the internal space of the docking scaffold. FIG. 26A
illustrates a top view of a docking scaffold. In FIG. 26A, a
double-walled filling structure 862 is coupled to the internal
surface of the docking scaffold 860. Two leg extension scaffolds
864 are slidably received by the docking scaffold 860. In FIG. 26B,
the filling structure 862 is filled with a hardenable filling
medium. The external wall of the filling structure 862 radially
expands outward to engage and seal against the inner surface of the
docking scaffold 860. The inner wall of the filling structure 862
radially expands inward to seal around the leg extension scaffolds
864.
[0079] The embodiments described above generally rely on radial
expansion of a filling structure to form a seal. The use of
thrombogenic materials in combination with a filling structure
enhances the resulting seal. In FIG. 27, the filling structure has
a plurality of filament-like hairs 880 coupled to an upper portion
of the filling structure. These hairs 880 may be made of any
thrombogenic material such as those disclosed herein or other
materials known in the art. Additionally, the hairs 880 may be
coupled with a thrombogenic agent to further cause clotting. The
hairs 880 cause blood to clot thereby further sealing the aneurysm.
The hairs 880 may be glued, bonded, welded, heat sealed, sintered,
sutured, electrospun, sprayed, vapor deposited, drape coated, press
fit or otherwise attached to the filling structure. Exemplary
materials for hairs 880 include but are not limited to
polyurethanes, polycarbonates, polyesters such as Dacron, ePTFE,
polyolefins, parylenes, gelatins, silicones, etc. The hair-like
structures 880 may be formed into sutures, felts, velours, weaves,
knits, hyodrogels, foams, embolization coils or sheets that are
attached to the filling structure. FIG. 28 shows an alternative
embodiment of a filling structure having a thrombogenic material
attached thereto. In FIG. 28, a cape 882 is attached to the filling
structure. The cape may drape over all or a portion of the filling
structure and is fabricated from any of the materials disclosed
herein. Because the cape is thin and flexible it will fit into the
space between the filling structure and the aneurysm wall and will
help form a blood clot which further creates a seal. The cape 882
may take any shape and may be attached to the filling structure
using any of the previously described methods. FIG. 29 illustrates
yet another embodiment of a filling structure with a thrombogenic
material attached thereto. In FIG. 29, an annular cuff 884 is
coupled with a neck region of the filling structure. The cuff may
be a Dacron cuff or it may be any material that is known to be
thrombogenic and it is attached to the filling structure using
techniques known to those of skill in the art. The cuff helps form
a seal by causing thrombosis in the neck region of the filling
structure. A cape structure having multiple lobes 1002 may also be
used to heal seal the aneurysm as shown in FIG. 33A. The lobes 1002
may be fillable or not. If fillable, as seen in FIG. 33B, the lobes
have a low profile prior to filling and a larger profile after
filling as seen in FIG. 33A.
[0080] Still another embodiment of a filling structure is one that
is seen in FIGS. 34A-34D. In FIG. 34A, multiple filling cylinders
1006, 1008, 1009 are stacked inside one another to create a tapered
or stepped filling structure as seen in FIG. 34C. FIG. 34C shows an
alternative embodiment of a stacked filling structure having three
cylinders 1010, 1012 and 1014. FIG. 34D shows the cylinders of FIG.
34B after they have been stacked together.
[0081] Another filling structure embodiment is seen in FIGS.
35A-35B. In FIG. 35A the inner wall of the filling structure forms
lumen 3500. Lumen 3500 includes a straight tubular section 3501 and
tapered portions 3502 and 3503 near the ends of the filling
structure. The tapered portions 3502 and 3503 flare radially
outward. Fill port 3504 is recessed into the tapered part of lumen
3503. This substantially prevents the fill port from contacting the
aneurysm wall once the filling structure is filled. FIG. 35B shows
an end view of the filling structure seen in FIG. 35A. In FIG. 35B,
outer wall 3505 forms a round or oval shape and lumen 3500 is
generally round. Additionally, outer wall 3505 is invaginated
inwardly to form a convex end rim. The opposite end may also be
similarly formed. Fill port 3504 is situated within the tapered
part of lumen 3500. In further alternative embodiments, the fill
port may be located at either end of the fill structure, or may be
exposed to contact the aneurysm wall. The cross-sectional shape at
each end depends on the rate of taper of the corresponding tapered
portions 3502 and 3503, becoming more round as the ratio of length
to width of the tapered portion increases. The filling structure
may also comprise any of the sealing or other features disclosed
herein, such as a tapered shoulder illustrated in FIG. 7A.
[0082] In addition to filling structures and thrombogenic
materials, a resilient spring-like frame or skeleton may be used to
help radially expand the filling structure into engagement with the
aneurysm walls, thereby further enhancing the seal. For example, in
FIG. 30A, the filling structure comprises a plurality of elongate
struts 902 or ribs that are coupled with the filling structure. The
struts 902 are biased to flex radially outward, therefore after a
constraint is released, the struts will bow radially outward,
forcing the filling structure to also expand outward. FIG. 30B
illustrates another embodiment where the resilient frame comprises
a helical coil 904 and FIG. 30C illustrates how the resilient frame
may comprise struts which are transverse to the longitudinal axis
of the filling structure. The spring-like frame may be made from
any number of resilient metals such as stainless steel, nitinol or
resilient polymers. The frame may be coupled to the inside or
outside surface of the filling structure, or it may be embedded in
between the inner and outer filling structure walls.
[0083] Reinforcing the ends of the filling structures may also
provide a better seal since the reinforced region and/or lumen L
will be rigid and cannot collapse. FIGS. 31A-31C illustrate
exemplary embodiments of reinforced filling structures. In FIG.
31A, the filling structure comprises narrow neck regions 912, 914
on both ends of the main body. One of the narrow neck regions 912
is reinforced with a frame to provide additional stiffness in that
region. The opposite narrow neck region 914 is shown unreinforced
although it may also be reinforced. FIG. 31B illustrates
reinforcement 916 along the entire filling structure longitudinal
axis. FIG. 31C illustrates reinforcement on opposite ends 918, 920
of the filling structure with connector struts 922 joining both
reinforced ends 918, 920. The reinforced areas may be metal,
polymers or combinations thereof. Various reinforcing patterns may
be used such as those well known in the stent and stent-graft arts.
For example, the reinforced areas may have sine wave like patterns
932 as seen in FIG. 32A, diamond shapes 934 as in FIG. 32B, weaves
936 as in FIG. 32C or helical coils 938 as in FIG. 32D. Many other
geometries may also be used.
[0084] A number of embodiments of filling structure have been
disclosed. Any combination of these embodiments may also be made or
substituted with one another. While use of the filling structures
may have been described with respect to a two piece or a three
piece endograft system, one of skill in the art will appreciate
that any filling structure may be used in any endograft system.
Additional features such as thrombogenic materials, thrombogenic
agents, radially expanding frames and reinforced regions have also
been discussed. Any of these features may also be used in
combination with any of the filling structures.
[0085] A number of thrombogenic materials have also been disclosed
such as polyurethanes, polycarbonates, polyesters, ePTFE,
polyolefins, parylene, gelatin, silicone, etc. Any of these
materials may be used as the thrombogenic material and these
materials may be formed into any number of configurations such as
sutures, felts, velours, weaves, knits, hydrogels, foams,
embolization coils or sheets. Attachment methods include but are
not limited to gluing, heat sealing, welding, sintering,
suturing/sowing, electrospinning, spraying, vapor deposition or
drape coating. The thrombogenic materials may be fabricated as a
part of the filling structure or they may be introduced during
deployment of the filling structure.
[0086] In addition to using thrombogenic materials, the surfaces of
the filling structure may be modified in order to provide various
material properties. For example, the surface may be textured,
dimpled, etc. in order to provide a surface that helps provide the
desired amount of thrombogenicity. Furthermore, the preferred
embodiments have been disclosed as being composed of ePTFE with an
inner layer of polyurethane. Other materials may be used as the
filling structure base material and a second or third or even more
layers of other materials may be coupled to the base layer in order
to provide the desired material characteristics of the filling
structure. Specific regions of the filling structure may also be
modified with a material or drug to provide a desired effect, for
example, a portion of the filling structure may be modified to be
thrombogenic to help create a seal while other regions remain
unmodified or modified to have a different effect. Other materials
or therapeutic agents like heparin may also be applied to the
surface of the tubular lumen to minimize thrombogenicity, or to
promote healing and endothelialization as blood flows
therethrough.
[0087] Filling materials may be any one or combination of materials
that may fill the filling structure and be hardened in situ.
Examples of filling materials include polyethylene glycol (PEG),
silicones, etc. One of skill in the art will appreciate that any of
the features disclosed herein may be substituted or combined with
any of the embodiments described herein. Moreover, in this
disclosure the filling structure is referred to as having an inner
wall and an outer wall that may be filled and that can withstand
pressures of approximately from about 30 mm Hg to about 300 mm Hg
above normal systolic blood pressure. One will appreciate the
filling structure may also have multiple layers. For example, as
disclosed, often the filling structure comprises an ePTFE layer
with a coating of polyurethane thereover. Additional layers with
other materials may similarly be used in order to control the
material properties such as porosity and compliance. Therapeutic
agents may also be coupled to the filling structure such as a
thrombogenic agent on the outside of the filling structure.
[0088] While the above is a complete description of the preferred
embodiments of the invention, various alternatives, modifications,
and equivalents may be used. Therefore, the above description
should not be taken as limiting in scope of the invention which is
defined by the appended claims.
* * * * *