U.S. patent application number 15/203580 was filed with the patent office on 2017-05-11 for devices and methods for treatment of abdominal aortic aneurysm.
The applicant listed for this patent is The Foundry, LLC. Invention is credited to Benard Andreas, Sunmi Chew, Mark Deem, Ron French, Hanson S. Gifford, III, Doug Sutton.
Application Number | 20170128240 15/203580 |
Document ID | / |
Family ID | 33310679 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170128240 |
Kind Code |
A1 |
Deem; Mark ; et al. |
May 11, 2017 |
DEVICES AND METHODS FOR TREATMENT OF ABDOMINAL AORTIC ANEURYSM
Abstract
Devices and methods for treating aneurysms, such as abdominal
aortic aneurysms ("AAA") generally include one or more stent-graft
devices. Some embodiments include self-expanding and/or
balloon-expandable stent components and one or more graft
components coupled with the stent components. Using various
combinations of self-expanding stent members, balloon-expandable
stent members, graft members, and/or anchoring members enhances the
anchoring abilities of a stent-graft device to prevent leakage
around it, and may further allow the device to be adjusted after
placement at a site for treatment. Some embodiments further include
a skirt graft member for further prevention of leakage and/or
device slippage.
Inventors: |
Deem; Mark; (Mountain View,
CA) ; Gifford, III; Hanson S.; (Woodside, CA)
; Andreas; Benard; (Redwood City, CA) ; Chew;
Sunmi; (San Jose, CA) ; French; Ron; (Santa
Clara, CA) ; Sutton; Doug; (Pacifica, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Foundry, LLC |
Menlo Park |
CA |
US |
|
|
Family ID: |
33310679 |
Appl. No.: |
15/203580 |
Filed: |
July 6, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14173642 |
Feb 5, 2014 |
9408688 |
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15203580 |
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10791469 |
Mar 1, 2004 |
8679171 |
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14173642 |
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60458286 |
Mar 26, 2003 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2002/077 20130101;
A61F 2230/006 20130101; A61F 2250/0048 20130101; A61F 2220/0058
20130101; A61F 2230/0054 20130101; A61F 2/89 20130101; A61F
2250/0003 20130101; A61F 2220/0008 20130101; A61F 2220/005
20130101; A61F 2002/061 20130101; A61F 2002/067 20130101; A61F
2210/0057 20130101; A61F 2/856 20130101; A61F 2002/075 20130101;
A61F 2002/065 20130101; A61F 2230/0034 20130101; A61F 2230/0069
20130101; A61F 2/07 20130101 |
International
Class: |
A61F 2/856 20060101
A61F002/856; A61F 2/89 20060101 A61F002/89 |
Claims
1. A stent for implanting in a vessel, said stent comprising: an
expandable stent having a first end, a second end opposite the
first end and a central lumen extending therebetween, wherein the
expandable stent has a collapsed configuration and an expanded
configuration, wherein in the collapsed configuration the stent is
configured for delivery to a vessel, wherein in the expanded
configuration, at least a portion of the stent is configured to
engage the vessel, and wherein in the expanded configuration the
central lumen forms a helix between the first and second ends.
2. The stent of claim 1, wherein the stent is balloon
expandable.
3. The stent of claim 1, wherein the stent is self-expanding.
4. The stent of claim 1, wherein in the collapsed configuration,
the stent is disposed in a straight configuration.
5. The stent of claim 1, further comprising a tubular graft member
coupled with the expandable stent.
6. The stent of claim 1, wherein the stent is pre-formed with a
helical portion having shape memory characteristics that allow it
to resume a helical shape once delivered.
7. The stent of claim 1, wherein in the expanded configuration the
stent is configured to engage the vessel thereby preventing leakage
therearound.
8. The stent of claim 1, wherein the vessel is an artery.
9. The stent of claim 8, wherein the artery is an iliac artery, a
carotid artery, a cerebral artery, or a coronary artery.
10. The stent of claim 1, wherein the stent comprises a series of
diamond shaped sections.
11. The stent of claim 1, wherein the stent comprises a wire wound
in a helical fashion.
12. The stent of claim 1, wherein the helical configuration
provides 360 degrees of helix.
13. The stent of claim 1, wherein the helical configuration
provides 540 degrees of helix.
14. The stent of claim 1, wherein the helical configuration
provides greater than 540 degrees of helix.
15. The stent of claim 1, wherein the stent is configured for
implantation in an aorta.
16. The stent of claim 1, wherein the stent provides long-term
elasticity and laminar flow without causing dramatic
atherosclerotic response within the stent due to turbulence or
shear.
17. A method for implanting a stent in a vessel, said method
comprising: providing an expandable stent having a first end, a
second end opposite the first end and a central lumen extending
therebetween; delivering the expandable stent in a collapsed
configuration to a treatment region in the vessel; expanding the
stent from the collapsed configuration to an expanded configuration
in which the stent at least partially engages the vessel, and
wherein expanding the stent forms the central lumen into a helix,
the helix disposed between the first and second ends.
18. The method of claim 17, further comprising permitting blood
flow through the helical central lumen, wherein the helical central
lumen creates sufficiently laminar blood flow.
19. The method of claim 18, wherein the sufficiently laminar blood
flow avoids causing an atherosclerotic response in the vessel due
to turbulence or shear in the blood flow.
20. The method of claim 17, wherein expanding the stent comprises
expanding the stent with a balloon.
21. The method of claim 17, wherein expanding the stent comprises
allowing the stent to self-expand.
22. The method of claim 17, wherein expanding the stent comprises
releasing the stent from a sheath or constraining device, thereby
allowing the stent to self-expand.
23. The method of claim 17, wherein delivering the stent in the
collapsed configuration comprises maintaining the stent in a
straight configuration.
24. The method of claim 17, wherein providing the expandable stent
further comprises providing a tubular graft member coupled with the
expandable stent.
25. The method of claim 17, wherein expanding the stent to engage
the vessel comprises preventing fluid leakage therearound.
26. The method of claim 17, wherein the vessel comprises an
artery.
27. The method of claim 26 wherein the artery comprises an aorta,
an iliac artery, a carotid artery, a cerebral artery, or a coronary
artery.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/173,642 now U.S. Pat. No. ______ (Attorney
Docket No. 38077-706.301) filed Feb. 5, 2014, which is a
continuation of U.S. patent application Ser. No. 10/791,469 now
U.S. Pat. No. 8,679,171 (Attorney Docket No. 38077-706.201) filed
Mar. 1, 2004 which is a non-provisional of, and claims the benefit
of U.S. Provisional Patent Application No. 60/458,286 (Attorney
Docket No. 38077-706.101) filed Mar. 26, 2003; the entire contents
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to devices and methods for
treating aneurysms. More particularly, the invention relates to
devices and methods for treating abdominal aortic aneurysms
including stents with self-expanding and balloon-expandable
features.
[0003] An aneurysm is a sac formed by localized dilatation of the
wall of an artery, a vein, or the heart. Common areas where
aneurysms occur and cause potential medical conditions include the
coronary arteries, the carotid arteries, various cerebral arteries,
and the abdominal aorta. When a local dilatation of a vessel
occurs, irregular blood flow patterns result, typically leading to
accumulation of cellular material and thrombus formation.
Typically, the wall of the vessel also progressively dilates and
weakens, causing the aneurysmal sac to grow and often resulting in
vessel rupture. Vessel rupture, in turn, often causes dramatic
negative health consequences such as a stroke, when a cerebral
vessel ruptures, or even death, when an abdominal aortic aneurysm
("AAA") ruptures. In light of these consequences, improved
treatment methods and devices for aneurysms are constantly being
sought. Although the following discussion focuses on AAA treatment,
it is equally applicable to aneurysms in other locations.
[0004] The abdominal aorta is the portion of the aorta (the body's
largest artery) located within the abdominal cavity. It functions
to carry blood from the heart to the lower extremities and
abdominal organs. Typically, the abdominal aorta has a diameter of
about 2 cm to 2.5 cm in an adult and extends in a relatively
straight path from the heart towards the groin, bifurcating into
the iliac arteries to supply blood to the legs.
[0005] Generally, AAA's are located within the aorta between the
renal arteries superiorly and in the bifurcation into the iliac
arteries inferiorly. Although at first an aneurysm may be quite
small, as the disease process continues an aneurysm enlarges, the
aorta wall thins, and rupture typically results. When the aneurysm
is less than 4.5 cm in diameter, danger of rupture is quite low.
Even before the aneurysm grows large enough to pose a danger of
rupture, however, it may cause other problems. The enlarged region
often develops a thrombus that fills the distension so that blood
flows only down the central region. Pieces of clot may break off
from the thrombus and be carried away, resulting in blockages in
the legs, lungs or even the brain.
[0006] Furthermore, an aneurysm typically enlarges at a rate of
0.3-0.5 cm per year. An aneurysm of 8 cm in diameter has
approximately a 75% per year rupture risk, with consequences of
rupture often being fatal. About 15,000 people die each year in the
United States from ruptured AAA's. Over 60% of people who suffer a
ruptured AAA die before reaching a hospital. Those who survive long
enough to undergo surgery typically face a 50% survival rate. Even
if the aneurysm is discovered before rupture, surgical repair is
difficult and risky although surgery is 95% successful.
[0007] Traditional AAA repair methods include open abdominal
surgery, in which the AAA is accessed through the abdomen, the
portion of the aorta containing the aneurysm is clamped off, the
aorta is incised, clot is removed and the aorta is manually
repaired with stents, graft material and/or other devices. Newer,
endovascular repair techniques generally involve placing a device,
including one or more stents and/or grafts across the aneurysm
through the vasculature rather than via an open surgical
procedure.
[0008] A stent is generally a hollow, cylindrical, expandable
device used to prop open a blood vessel to preserve or restore it
patency. Stents are usually made of metallic mesh-like material,
which may be either self-expanding or manually expandable.
Self-expanding stents have shape memory capabilities, so that they
can be compressed into a smaller shape for positioning at an area
of treatment and then allowed to expand to attach to the desired
area. Expandable stents are typically positioned at a desired
location and then expanded by an inflatable device, typically a
balloon, to attach the stent in the desired location.
[0009] Another device commonly used in vascular repair is a
vascular graft, typically made of a synthetic material such as
polytetrafluoroethylene (PTFE). An advantage of these synthetic
grafts is that they are extremely flexible and can be readily
compressed to a very small size for endovascular insertion.
Application of a graft alone, however, generally requires suturing
of the graft to the wall of the aorta, which requires an open
procedure.
[0010] Many currently available AAA devices combine one or more
synthetic graft components with one or more stent components. The
stent component generally anchors the device in a desired location
and maintains the patency of the vessel, while the graft component
prevents thrombus from entering through the mesh-like structure of
the stent and reinforces the wall of the aorta. Typically, such a
device is placed across a AAA, often through a large aortic
thrombus, to act as a new blood vessel. For example, some devices
include a stent component for placement above the aneurysm, near
the renal arteries, a graft component to cross the aneurysm, and
one or more additional stent components to anchor the device distal
to the aneurysm.
[0011] One recurring problem in AAA repair with stent or
stent-graft devices is stress placed on such devices by motion. One
type of motion that effects a AAA repair device is bending motion
by the patient. Currently available devices try to address such
motion by either providing a stronger, stiffer stent-graft to
minimize bending of the device or providing a more flexible device
to minimize stresses on the device.
[0012] Another type of motion that stresses AAA stent-graft devices
but which has been largely ignored in AAA stent-graft design is
longitudinal movement, causing stretching and/or compression of a
stent-graft. Such stretching and/or compression may occur in either
of at least two ways--acute stretching or compression of the
vasculature due to the patient's body motion and gradual stretching
or compression of the vasculature as the aneurysm grows or shrinks
due to the presence of the graft. This stretching or compression
applies significant stresses to the proximal and distal seals of
the graft, and can be one of the major causes of graft migration
and leakage of the seals over time. It can also lead to structural
failures of the stent-graft, such as separation of graft elements
fracture in the body of the graft or the like.
[0013] Another frequent problem faced in AAA repair with
stent-graft devices is leakage of blood around the outside of the
device. Such leakage allows blood to circulate through the
aneurysm, rather than through the device. This flow of blood
outside the device causes the blood pressure within the aneurysm to
increase and the size of the aneurysm to progressively grow,
increasing the risk of rupture. One cause of such leakage is
inadequate initial attachment of the device to the internal surface
of the wall of the aorta proximal to the aneurysm. If attachment,
or "anchoring" of the proximal portion of the device is inadequate,
blood typically leaks between the device and the wall of the aorta,
into the aneurysm.
[0014] Leakage of blood around a AAA stent-graft may also occur
when such a device becomes loose after an initially adequate
anchoring. In other words, even if a stent-graft is initially
anchored sufficiently, the device may lose its tight fit after a
period of use. A loosened stent-graft may slip distally, pushed by
the flow of blood, which may further compromise the fit of the
device within the aorta, causing further leakage. When such
loosening, slippage and/or leakage occurs in currently available
stent-graft devices, the devices must typically be replaced via an
additional surgical procedure.
[0015] Generally, leakage around a AAA stent-graft is usually
caused by one or more stresses on the device. Two types of
stresses--bending and longitudinal--have been discussed above. A
third type of stress on the seal of a AAA stent-graft is
diametrical expansion and contraction of the blood vessel at the
seal location over time, without matching expansion of the graft.
This is caused both by cyclical variations in blood pressure, as
well as gradual expansion or contraction of the blood vessel over
time. A fourth stress is the hydrostatic pressure of blood against
the graft. For the upper seal of the AAA graft system in the aorta,
this pressure equals the cross-sectional area of the graft times
the aortic blood pressure. For an aorta diameter of 26 mm, and a
blood pressure cycling between 80 mmHg and 150 mmHg, this force
equals 0.823 sq.in.*1.55 psi-2.90 psi, or 1.28-2.39 lbs. A similar
estimate of the hydrostatic stress on an iliac seal of 14 mm
diameter gives an estimate of 0.37-0.69 lbs.
[0016] When a graft such as a knitted Dacron graft is affixed to
the inner surface of a human artery, the body's natural healing
response causes ingrowth of endothelial tissue, scar tissue or
pannus into the graft element. This healing response will typically
create a hemostatic seal of the graft to the vessel wall over time,
unless that healing response is disturbed by stresses or motion of
the graft relative to the vessel wall. The tissue which forms this
seal typically does not have significant structural strength, and
the stent-graft may often be easily pulled loose or dissected from
the vessel wall when due to one or more of the mechanical stresses
described above.
[0017] Although efforts have been made to design a AAA stent-graft
having a stronger graft-vessel wall connection, these attempts have
met with limited success. Designing the graft to apply additional
radial outward force against the vessel wall only gains a certain
amount of longitudinal resistance to movement or migration.
Building the graft with hooks or other anchors increases the risk
of trauma to the vessel wall and the risk of fatigue failure of
those anchoring elements. Evidently, strengthening fixation of the
graft at the seal areas may be limited.
[0018] Therefore, it would be advantageous to have devices and
methods to provide treatment of AAA with reduced leakage, slippage
and breakage of the AAA stent-graft device. Ideally, devices would
include adequate anchoring features to prevent both leakage and
slippage of the device. There is also a need for a flexible device
to allow for repeated bending, stretching and compression forces
over time without breaking or significantly reducing the efficacy
of the device. It would also be desirable for such devices to be
adjustable once placed in a location in the aorta for treatment, so
that devices which lose their fit within the aorta may be adjusted
rather than replaced. At least some of these objectives will be met
by the present invention.
BRIEF SUMMARY OF THE INVENTION
[0019] Generally, the present invention provides devices and
methods for treating aneurysms. Although many types of aneurysms
may be treated, such as cerebral, carotid and coronary aneurysms,
the following discussion focuses on the treatment of abdominal
aortic aneurysms ("AAA"). More specifically, stent-graft devices
and methods for treating AAA include self-expanding and/or
balloon-expandable stent components and one or more graft
components coupled with the stent components. Using various
combinations of self-expanding stent members, balloon-expandable
stent members, graft members, and/or anchoring members enhances the
anchoring abilities of a stent-graft device to prevent leakage
around it, and may further allow the device to be adjusted after
placement at a site for treatment. Some embodiments further include
a skirt graft member for further prevention of leakage and/or
device slippage.
[0020] In one aspect of the invention, a stent-graft device for
treating an abdominal aortic aneurysm comprises at least one stent
member comprising at least one of a self-expanding stent member and
a balloon-expandable stent member, and at least one tubular graft
member coupled with the at least one stent member, the tubular
graft member having a proximal end and at least one distal end.
[0021] In some embodiments, the stent member includes at least one
self-expanding stent member and at least one balloon-expandable
stent member coupled with the self-expanding stent member.
Optionally, the at least one self-expanding member and the at least
one balloon-expandable member comprise a plurality of alternating
members, every other alternating member comprising either a
self-expanding material or a balloon-expandable material. The
balloon-expandable material may, for example, be made of stainless
steel and the self-expanding material may be made of nitinol,
though any other suitable material(s) may be used. In some
embodiments, the alternating members are coupled together with one
or more pieces of adhesive. Optionally, this adhesive may further
couple the alternating members with the tubular graft member. In
some embodiments, the alternating members are coupled together via
one of welding, soldering or tying, though any other method and/or
means for coupling the members is contemplated. In some
embodiments, the alternating members comprise a plurality of
diamond-shaped members coupled together to form a cylindrical
stent, though any other shapes and configurations are
contemplated.
[0022] In some embodiments, the at least one tubular graft member
comprises a main graft member toward the proximal end of the
tubular graft member and at least one leg having a proximal end and
a distal end, each leg member being coupled with the main graft
member at its proximal end and extending toward the distal end of
the tubular graft member. Optionally, the at least one leg member
may comprise two leg members for coupling the distal end of the
tubular graft member with two iliac arteries branching from the
abdominal aorta. In some embodiments, the two leg members comprise
two sinusoidal leg members. Optionally, the two sinusoidal leg
members may be helically intertwined. Furthermore, in some
embodiments, each of the two leg members is coupled with an iliac
stent member at its distal end. Sometimes the iliac stent member
comprises at least one of a self-expanding stent member and a
balloon-expandable stent member. In various embodiments, each of
the two leg members is removably couplable with the main graft
member. Also in some embodiments, the main graft member may be
coupled with at least one stent member at the proximal end of the
tubular graft member, and each of the at least one leg members is
coupled with at least one stent member at the distal end of the
tubular graft member. Optionally, the device may also include a
skirt graft member coupled with at least one of the main graft
member and the stent member near the proximal end and extending
toward the distal end.
[0023] Some embodiments of the device also include a suprarenal
anchoring member coupled with the stent member for anchoring the
stent-graft device at a location superior to renal arteries
branching from the abdominal aorta. For example, in some
embodiments the suprarenal anchoring member comprises at least one
of a self-expanding stent member and a balloon expandable stent
member. The suprarenal anchoring may be coupled with at least one
of the self-expanding stent member and the balloon expandable stent
member by any suitable means, such as but not limited to wire,
ribbon, rods and/or bands of material. Some embodiments may further
comprise an infrarenal anchoring member coupled with at least one
of the stent member and the suprarenal anchoring member for further
anchoring the stent-graft device at a location inferior to the
renal arteries. In some cases, the infrarenal anchoring member
comprises at least one of a self-expanding stent member and a
balloon expandable stent member. Alternatively, the infrarenal
anchoring member may be included in some embodiments without a
suprarenal member.
[0024] Any other suitable components may be included with a
stent-graft device. In one embodiment, for example, a stent-graft
further includes at least one expandable balloon member coupled
with the at least one balloon-expandable stent member for expanding
the balloon-expandable stent member. As mentioned, other
embodiments include at least one skirt graft member coupled with at
least one of the stent member and the tubular graft member at or
near the proximal end of the tubular graft member and extending
toward the distal end.
[0025] In another aspect of the invention, a stent device for
treating an aneurysm includes at least one self-expanding stent
member and at least one balloon-expandable stent member coupled
with the self-expanding stent member. As described above, the at
least one self-expanding member and the at least one
balloon-expandable member may comprise, in some embodiments, a
plurality of alternating members, every other alternating member
comprising either a self-expanding material or a balloon-expandable
material. The aspects of such a stent have been described above.
Such a stent device may further include one or more graft devices
coupled (or removably couplable) with the stent member(s). Such a
graft member may have any of the aspects and characteristics
already described.
[0026] In another aspect, a stent-graft device for treating an
abdominal aortic aneurysm comprises: a proximal stent member for
coupling the stent device with the abdominal aorta proximal to the
aneurysm; at least one distal stent member for coupling the stent
device with a blood vessel distal to the aneurysm; and at least one
graft member coupled with and extending between the proximal stent
member and the at least one distal stent member, at least a portion
of the graft member having a sinusoidal shape. In some embodiments,
the at least one distal stent member comprises two iliac stent
members for coupling the stent-graft device with two iliac arteries
branching from the abdominal aorta. Furthermore, in some
embodiments, the graft member may include a main graft member
coupled with the proximal stent member; and two leg members, each
leg member coupled with the main graft member and one of the two
iliac stent members. Alternatively, the at least one graft member
may include a main graft member coupled with the proximal stent
member and two leg members, each leg member removably couplable
with the main graft member and coupled with one of the two iliac
stent members.
[0027] In some embodiments, the proximal stent member and/or the
distal stent member comprises at least one self-expanding stent
member and at least one balloon expandable stent member coupled
with the self-expanding stent member. Some embodiments further
include a suprarenal anchoring member coupled with the proximal
stent member for anchoring the stent-graft device at a location
superior to at least one renal artery branching from the aorta. The
suprarenal anchoring member may comprise, in some embodiments, at
least one of a self-expanding member and a balloon expandable
member. Some embodiments may further comprise at least one skirt
member coupled with the proximal stent member and extending
distally.
[0028] In yet another aspect, a kit for treating an abdominal
aortic aneurysm comprises: at least one stent-graft device for
treating the aneurysm; at least one stent-graft positioning device
positioning the at least one stent-graft device in the abdominal
aorta to treat the aneurysm; and instructions for using the
stent-graft device and the positioning device.
[0029] In another aspect, a method for treating an abdominal aortic
aneurysm involves: positioning at least one stent-graft device in
the abdominal aorta in a location for treating the aneurysm, the at
least one stent-graft device having at least one self-expanding
member and at least one balloon-expandable member coupled to the
self-expanding member, and deploying the at least one stent-graft
device to contact a portion of the abdominal aorta with at least a
portion of the device.
[0030] In some embodiments, positioning the at least one
stent-graft device comprises positioning a proximal stent member at
a location within the aorta inferior renal arteries which branch
from the aorta and superior to the aneurysm. Optionally,
positioning the at least one stent-graft device may also include
positioning at least one distal stent member at a location within
at least one iliac artery of a patient. Positioning the at least
one stent-graft device may further include positioning at least one
suprarenal anchoring member coupled with the at least one proximal
stent member at a location within the aorta superior to the renal
arteries. In some embodiments, positioning the at least one
stent-graft device comprises positioning the device over at least
one of a guidewire and a guide catheter. Also in some embodiments,
positioning the device comprises positioning at least one helical
leg portion of the device over at least one of the guidewire and
the guide catheter.
[0031] In some embodiments, deploying the at least one stent member
comprises: releasing the stent member from a containment member to
allow the at least one self-expanding member to expand; and
expanding the at least one balloon-expandable member with an
expandable balloon device. Some embodiments may further include
positioning a suprarenal anchoring member coupled with the
stent-graft at a location within an aorta superior the renal
arteries and releasing the suprarenal anchoring member from a
containment member to allow the suprarenal anchoring member to
expand and contact the wall of the aorta. Additionally, some
methods may include adjusting the stent-graft member by expanding
the at least one balloon-expandable member with a balloon expansion
device. Still other embodiments may include positioning a tubular
graft member coupled with at least one of the self-expanding member
and the balloon expandable member across at least part of the
aneurysm. Some embodiments include such steps as expanding a
balloon member within at least part of the aneurysm, positioning a
skirt member coupled with the stent-graft device within at least a
portion of aneurysm and the like. In some embodiments, the at least
stent-graft device comprises a plurality of coupled members, each
of the coupled members comprising either a balloon-expandable
material or a self-expanding material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a perspective view of a stent-graft device in
position for treating a AAA, according to one embodiment of the
present invention.
[0033] FIGS. 2a-c illustrate sections from a variety of stent
devices, showing coupling of self-expanding and balloon-expandable
members, according to various embodiments of the present
invention.
[0034] FIG. 3 is a perspective view of a stent-graft device in
position for treating a AAA, according to another embodiment of the
present invention.
[0035] FIG. 4 is a frontal view of a stent-graft device having a
sinusoidal portion in position for treating a AAA, according to
another embodiment of the present invention.
[0036] FIG. 5 is a frontal view of a stent-graft device having
sinusoidal leg portions in position for treating a AAA, according
to another embodiment of the present invention.
[0037] FIG. 6 is a frontal view of a stent-graft device having
sinusoidal leg portions with extra length in position for treating
a AAA, according to another embodiment of the present
invention.
[0038] FIG. 7 is a frontal view of a stent-graft device having
sinusoidal, helically wrapped leg portions in position for treating
a AAA, according to another embodiment of the present
invention.
[0039] FIGS. 8A and 8B are frontal views of stent-graft devices
having sinusoidal, helically wrapped leg portions in position for
treating a AAA, according to various other embodiments of the
present invention.
[0040] FIG. 9 is a frontal view of a stent-graft device having
sinusoidal, helically wrapped leg portions and showing a guide
catheter for in position for treating a AAA, according to another
embodiment of the present invention.
[0041] FIG. 10 is a frontal view of a stent-graft device having
sinusoidal, helically wrapped leg portions and a suprarenal anchor
in position for treating a AAA, according to another embodiment of
the present invention.
[0042] FIG. 11 is a frontal view of a portion of a stent-graft
device having a suprarenal anchor in position for treating a AAA,
according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Generally, the present invention provides devices and
methods for treating aneurysms. Although many types of aneurysms
may be treated, such as cerebral, carotid and coronary aneurysms,
the following discussion focuses on the treatment of abdominal
aortic aneurysms ("AAA"). More specifically, stent-graft devices
and methods for treating AAA include self-expanding and/or
balloon-expandable stent components and one or more graft
components coupled with the stent components. Using various
combinations of self-expanding stent members, balloon-expandable
stent members, graft members, and/or anchoring members enhances the
anchoring abilities of a stent-graft device to prevent leakage
around it, and may further allow the device to be adjusted after
placement at a site for treatment. Some embodiments further include
a skirt graft member for further prevention of leakage and/or
device slippage.
[0044] Although the following description focuses on embodiments of
devices and methods for AAA treatment, these or other embodiments
may suitably be used for treatment of many other aneurysms, such as
those of the cerebral arteries, coronary arteries, the heart and/or
the like. Furthermore, the following description typically focuses
on placement of one integrated device across a AAA, from a location
proximal to an aneurysm to locations within the iliac arteries. It
should be understood that multiple devices, combinations of devices
and the like may alternatively be used and that other treatment
locations are contemplated. For example, some devices may not
extend into the iliac arteries. Therefore, any devices and/or
methods including the use of one or more stents having
self-expanding and balloon-expandable features are contemplated
within the scope of the present invention. The description of
specific embodiments below should not limit the scope of the
present invention as set forth in the claims.
[0045] That being said, and referring now to FIG. 1, an aorta 100
is shown with a right renal artery 102a, a left renal artery 102b,
an aneurysm 104 in the wall of the aorta, a right iliac artery 106a
and a left iliac artery 106b. One embodiment of a device 101 for
treating aneurysm 104 suitably includes a first stent member 110,
with a right tubular member 120a forming a right lumen 112a and a
left tubular member 120b forming a left lumen 112b. The embodiment
of device 101 in FIG. 1 also includes a second stent member 122
extending proximally from first stent member 110, two iliac legs
116a, 116b coupled with the two tubular members 120a, 120b, and two
iliac anchoring stents 118a, 118b, each anchoring stent coupled
with one of iliac legs 116a, 116b. Finally, some embodiments of
device 101 will include one or more skirts 114 extending distally
from first stent member 110 within aneurysm 104 for further
positioning, holding in place and/or preventing leakage around
device 101.
[0046] First stent member 110 and iliac anchoring stents 118a, 118b
are pictured generally as a mesh material configured as a grid of
diamond-shaped elements. In one embodiment, alternating
diamond-shaped elements in a mesh may be formed from self-expanding
and balloon-expandable materials. In FIG. 1, this pattern is
designated by the labels in some of the diamonds of "S" for
"self-expanding" and "B" for "balloon-expandable." As is described
further below, such a configuration is only one possible embodiment
and many other suitable embodiments for stents and stent components
are contemplated.
[0047] It should be emphasized that FIG. 1 describes only one
exemplary embodiment and that many different embodiments of devices
for treatment of AAA are contemplated within the scope of the
invention. For example, some embodiments may include only stents,
some embodiments do not include second stent member 122, some
embodiments do not include separate tubular members 120a, 120b
and/or the like. Other embodiments may include more or fewer stent
members, graft members, skirts and/or any other suitable
configuration of elements for treating a AAA. In some embodiments,
iliac legs 116a and 116b may be fully supported by stent or other
scaffold structures along their entire length or over additional
portions of their lengths between the terminal stents 110, 118a,
and 118b. Also, as previously discussed above, this and other
embodiments may be used or adapted for use in blood vessels other
than the abdominal aorta, such as the carotid arteries, coronary
arteries, cerebral vessels, and/or the like.
[0048] That being said, first stent 110 is generally configured to
anchor device 101 by attaching to the wall of aorta 100 at a
location between aneurysm 104 and renal arteries 102a, 102b. First
stent 110 may thus include any device or combination of devices
suitable for anchoring the overall device to a vessel wall. For
example, in various embodiments first stent 110 may be entirely
self-expanding, entirely balloon expandable or a combination of
self-expanding and balloon expandable.
[0049] In one embodiment, as mentioned above and shown in FIG. 1,
alternating sections of first stent 110 are made of nitinol, a
self-expanding material (S), and stainless steel, a
balloon-expandable material (B). For example, alternating
diamond-shaped sections of first stent 110 are made from
self-expanding and balloon-expandable materials. Such a combination
may provide for a conveniently self-expanding stent which could be
further expanded by a balloon, to attach securely to the wall of
the aorta and prevent leakage of blood around the device. Many
other materials and configurations for making a stent are commonly
know to those skilled in the art and any suitable combination of
materials, configurations, sizes and the like may be used to make
first stent member 110. For example, the material used to
manufacture stent member 110 may be formed in any suitable pattern
or configuration. Alternatively, separate expansible stent sections
or scaffolds may be laminated to each other such that the overall
stent will have a combination of deformable and elastic
characteristics. The different layers may be laminated along their
entire interface surface, or otherwise held together at different
discrete points about their common circumferential interface.
[0050] Tubular member 120 is attached to stent 110 and is then
joined at the center to form separate tubular members 120a and 120b
to form two lumens 112a, 112b. Such lumens 112a, 112b typically
provide for attachment to first stent member 110 of two iliac legs
116a, 116b, so that tubular members 120a, 120b may direct blood
flow into the legs 116a, 116b. Materials used to make grafts, such
as polytetrafluoroethylene (PTFE) and other polymers, are well
known to those skilled in the art and any suitable material may be
used for tubular member 120. In some embodiments other grafts may
be attached to first stent member 110, such as a graft on the
outside of the stent and the like.
[0051] Skirt 114 extends distally from first stent member 110 and
typically is configured to be positioned in contact with the inner
wall of aorta 100. In various embodiments, skirt 114 may be made of
all stent material, all graft material, or a combination of stent
and graft material. As pictured in FIG. 1, skirt 114 is a
relatively freely-hanging graft material which may be placed in
contact with the inner wall of aorta 100. In other embodiments,
skirt 114 includes multiple stent-like legs and no graft material.
Any suitable configuration is contemplated.
[0052] Second stent member 122 is generally any stent configuration
capable of further anchoring the device by attaching to a location
proximal to renal arteries 102a, 102b--i.e., in a suprarenal
location. Typically, second stent member 122 will include only
stent material, so that blood flow through the device to renal
arteries 102a, 102b is not reduced. However, second stent members
122 including graft material or other suitable materials are
contemplated. As with first stent member 110, any suitable
material, such as nitinol, stainless steel, a combination thereof,
or the like, may be used to make second stent member 122. The
second stent member 122 may be formed integrally with the first
stent member 110 or may be formed as a discrete scaffold component
which is either attached or unattached to stent 110.
[0053] With reference now to FIGS. 10 and 11, one embodiment of
device 101 is shown, in which second stent member 122 comprises a
suprarenal anchoring member 412. A proximal stent member 408 (which
may variously be referred to as a "main stent member" or a "sealing
stent member") is coupled with aorta 100 at an infrarenal location.
Generally, suprarenal anchoring member 412 and proximal stent
member 408 may be coupled by any suitable means. In various
embodiments, for example, they may be coupled with wires, ribbons,
cables, bands and/or the like. Such connections prevent
foreshortening of the overall device during implantation. Although
these figures do not show hooks or anchors which penetrate the
aortic wall to enhance the fixation, such hooks could be included
if desired. Also, as shown best in FIG. 11, in some embodiments
proximal stent member 408 includes a two-lumen graft 414 into which
two graft legs, as described further below, may be introduced. In
other embodiments, however, proximal stent member 408 may have one
leg pre-attached, both legs pre-attached or the like.
[0054] Iliac legs 116a, 116b may be a part of the device or may be
provided separately from the device. Typically, iliac legs 116a,
116b will be positioned at the treatment area and attached to first
stent member 110 after stent member 110 is in place. In some
embodiments, however, iliac legs 116a, 116b may be pre-attached to
first stent member 110 before insertion, may be attached to another
component of the device, such as skirt 114, or the like. Generally,
iliac legs 116a, 116b are anchored to iliac arteries 106a, 106b by
iliac anchors 118a, 118b. Both legs 116a, 116b and anchors 118a,
118b may include any suitable combination of stent materials and/or
graft materials, as previously discussed above in relation to first
stent member 110. The legs 116a and 116b, as discussed above, are
shown to be supported by stents only at their ends. Alternatively,
the legs may be fully supported or additionally supported over the
entire length or a portion thereof. Other supports are possible,
including axial elements, discrete ring members attached to the
legs, and the like.
[0055] Referring now to FIGS. 2a-2c, sections 202a-c of various
embodiments of stent members are shown. Sections 202a-c represent
examples of stent members which may be used to form first stent
110, anchoring stent 122, second stents 118a, 118b and/or the like.
As previously discussed, many other embodiments may be suitable and
the devices of the present invention are not limited to
diamond-shaped grids, meshes or the like.
[0056] In one embodiment, as shown in FIG. 2a, section 202a of
stent members may include alternating balloon-expandable members
210a and self-expanding members 212a. Such members may be coupled
together by any suitable means, for example a coupling device 204.
Coupling device 204, in turn, may include any suitable device for
joining stent members together. In one embodiment, coupling device
204 may comprise an adhesive tape. The tape may not only couple the
stent members together, but may also couple the stent members to a
graft material or other component of the device. Any suitable
adhesive material may be used.
[0057] Referring now to FIG. 2b, in another embodiment
balloon-expandable stent members 210b and self-expanding stent
members 212b may be joined together at connection points 208 via
welding, soldering, adhesive and/or any other suitable connection
means. In some embodiments, for example, stent members may be
joined by laser welding at connection points 208.
[0058] In yet another embodiment, with reference now to FIG. 2c,
stent members 210c and 212c may be coupled via one or more wire
connectors 216. Wire connectors 216 may be configured of metallic
wire, suture material and/or any other suitable material for
joining stent members. In some embodiments, wire connectors 216 are
wound around stent members in a helical fashion. Wire connectors
216 may also be used in some embodiments to couple stent members to
one or more graft members.
[0059] Generally, as described above, stent devices of the present
invention may provide for prevention of leakage of blood around the
stent, for improved positioning and placement of a AAA treatment
device, for adjustment of a stent device after placement and/or the
like. Providing a combination of self-expanding and
balloon-expandable stent members within the same stent, such as in
first stent 110, anchoring stent 112, iliac stents 118a, 118b,
and/or other stents, allows a stent device to be partially
self-deploying and partially manually expanded by a balloon or
other expansive device. Methods of using devices of the present
invention, therefore, typically involve both a self-expanding
delivery component and a balloon-expandable delivery component.
[0060] Referring again to FIG. 1, inn one embodiment, a method
according to the present invention includes delivering a device 101
at a location within an abdominal aorta for treatment of a AAA.
Such delivery may be accomplished endovascularly or by any other
suitable means. Typically, device 101 will be positioned to cross
an aneurysm 104, from a location proximal to aneurysm 104 to a
location distal to aneurysm 104. At the distal location, one or
more portions of device 101 may be positioned for coupling with
aorta 100, iliac arteries 106a, 106b, or both.
[0061] After device 101, or some portion of device 101, has been
positioned in a desired location, one or more of the stents
included in the device may be deployed. For example, first stent
member 110 and anchoring stent member 122 may be deployed at a
location proximal to aneurysm 104 before deploying the rest of
device 101. Generally, a stent including self-expanding members may
be deployed by releasing the stent from a sheath or other
constraining device. If the stent also includes balloon-expandable
members, it may be further expanded with a balloon device or other
expansion device. For example, first stent member 110 may be
positioned at a desired location within aorta 100, typically distal
to renal arteries 102a, 102b and proximal to aneurysm 104, and then
allowed to self-expand to contact the inner surface of the wall of
aorta 100. First stent 110 may additionally be further expanded by
positioning a balloon expansion device within the stent and
expanding the balloon. This may allow first stent member 110 to
achieve a firmer or more stable contact with aorta. Anchoring stent
member 122, iliac stent members 118a, 118b, and/or any other stent
members included in device 101 may be deployed in similar
manner.
[0062] Referring now to FIG. 3, another embodiment of device 101
suitably includes an inflatable balloon 310 or bladder. Balloon 310
may comprise graft material, stent material or a combination
thereof, and may be attached to any portion of device 101 in any
suitable manner. Balloon 310 will typically be inflatable with a
liquid, air or other inflation means via an inflation lumen. When
inflated, balloon 310 may assume any suitable shape for enhancing
the fit of device 101 within aorta 100. For example, balloon 310
may expand to fill an aneurysmal sac 104 or any other irregularity
in the shape of the inner wall of aorta 100. Generally, an inflated
or expanded balloon 310 coupled with device 101 will be configured
to help hold the device in a desired position within aorta 100 and
to reduce movement or slippage of device 101 within aorta 100. As
such, balloon 310 typically enhances leakage prevention.
[0063] Referring now to FIG. 4, a frontal view of aorta 100 with
aneurysm 104 shows an embodiment of device 101 having a
sinusoidal-shaped graft portion 400. To enhance longitudinal
flexibility (or "stretchiness" or "elasticity") of device 101, one
or more bends may be included in a portion of device 101, such as
sinusoidal graft portion 400. These bends allow device 101 to
straighten and/or bend in one or more directions to absorb length
changes to which device 101 is subjected and thus reduce
stress/strain on device 101. FIG. 5 show a similar embodiment of
device 101 having two sinusoidal graft legs 402a-b. In some
embodiments, such devices 101 may be delivered in a straight
configuration, for ease of delivery, and then may have shape memory
characteristics allowing them to resume their sinusoidal shapes
once delivered. Generally, sinusoidal graft portions 400 or legs
402 provide long-term elasticity and also provide relatively
laminar flow, without causing dramatic atherosclerotic response
within the graft due to turbulence or shear.
[0064] In other embodiments, which may look similar to those shown
in FIGS. 4 and 5, graft legs might be made very flexible and be
delivered with significant extra slack between the proximal and
distal ends, so they form one or more bends in the body of the
aneurysm. Such an arrangement would have almost zero column
strength from the aortic fixation point to the iliac fixation
point. Any relative flexion or tension between fixation points
would put almost no stress on the graft or the fixation points. To
ensure a desired amount of slack is introduced on deployment, the
graft legs might be deployed first in the proximal anchor element,
and then significant excess graft length might be deployed in the
body of the aneurysm prior to deploying the other end of the graft
in the iliac artery.
[0065] Referring now to FIGS. 6-8, in some embodiments, to prevent
excessive acute bending of the excess graft in the aneurysm body,
graft legs 402 may be wrapped around each other in a helical
fashion. For example, graft legs 402 may be wrapped around each
other to provide 360 degrees of helix, 540 degrees, or even more,
as shown in the in FIGS. 8A and 8B, which show increasing amounts
of helix. Furthermore, as shown in FIGS. 6 and 7, a helix of legs
402 may run in either direction. Generally, such helices may have
any suitable configuration. Although graft legs 402 are typically
loosely wrapped/entwined, to provide desired slack, any suitable
wrapping pattern, tightness, and the like is contemplated within
the scope of the invention.
[0066] Generally, the helical configuration just described and
shown in FIGS. 6-8 will be deliverable by any suitable technique,
such as delivery techniques already known in the art and/or novel
methods. Referring now to FIG. 9, for example, in one embodiment
the following delivery method may be used. First, one graft leg
402a is deployed with a reasonable amount of slack. This
first-deployed leg 402a could either be integral with the upper
graft element, or separate. Then, from the contralateral leg, a
second leg 402b is introduced (not shown in FIG. 9). This second
leg 402b would be introduced over a guidewire 404 and/or guiding
catheter 406 which may have a pre-shaped helical curve at the
distal end. Rotation of guidewire 404 and/or guiding catheter 406
would cause them to wrap around first graft leg 402a in the
abdominal aorta 100, and they would then be advanced through the
upper graft element. Second graft leg 402b would then be introduced
over guidewire 404 and/or guide catheter 406 guide. In one
embodiment there is an overlap of at least 2 cm and preferably 3 cm
between legs 402 and the upper graft element, to minimize the risk
of slippage and allow for some misalignment upon deployment by the
physician, although other overlap sizes are contemplated.
[0067] In some embodiments, graft legs 402 will be preformed with
the desired helical shape. The graft and delivery system would
still be flexible, and would straighten out for introduction into
the femoral or iliac artery, but would resume the appropriate
helical shape once they were positioned within the body of aneurysm
104. This pre-shaped curve may facilitate delivery of a desired
amount of slack and wrapping of one leg 402a around the other leg
402b during delivery. As already mentioned, and as shown in FIGS. 6
and 7, in some embodiments it may be advantageous to have a device
101 having a helix in one direction, while in others the opposite
direction of helix may be superior. Any such configurations are
contemplated within the scope of the invention.
[0068] As discussed, stent-graft devices of the invention may have
any suitable configuration and may be made of any suitable material
or combination of materials. In one embodiment, for example, device
101 may have a diameter in the range of about 12 mm to 16 mm, which
may be compressible to a size acceptable for endovascular delivery,
for example of 24 French or less, and more preferably less than 20
french, and even more preferably less than 14 french. In one
embodiment, for example a Viabahn or Endobahn endovascular covered
stent prosthesis manufactured by WL Gore may be used for one or
more legs 402 of device 101, though any other suitable material(s)
may be used.
[0069] Although exemplary embodiments of methods and devices have
been disclosed herein, it should be apparent from the foregoing
description that variations and modifications of such embodiments
may be made without departing from the scope of the invention.
Therefore, the above description should not be taken as limiting
the scope of the invention which is defined by the appended
claims.
* * * * *