U.S. patent application number 17/119884 was filed with the patent office on 2021-04-01 for system and methods for endovascular aneurysm treatment.
The applicant listed for this patent is Nellix, Inc.. Invention is credited to Michael A. Evans, Steven L. Herbowy, Amy Lee, Gwendolyn A. Watanabe.
Application Number | 20210093473 17/119884 |
Document ID | / |
Family ID | 1000005266389 |
Filed Date | 2021-04-01 |
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United States Patent
Application |
20210093473 |
Kind Code |
A1 |
Evans; Michael A. ; et
al. |
April 1, 2021 |
SYSTEM AND METHODS FOR ENDOVASCULAR ANEURYSM TREATMENT
Abstract
Embodiments provide methods and systems for treating aneurysms
using filling structures filled with a curable medium An embodiment
of a method comprises positioning at least one double-walled
filling structure across the aneurysm and filling the structure(s)
with a filling medium so that an outer wall conforms to the inside
of the aneurysm and an inner wall forms a generally tubular lumen
to provide for blood flow. The lumen is supported with a balloon or
other expandable device while and/or after filling. The pressure
within the structure and/or in the space between an external wall
of the structure and the aneurysm wall is monitored and a flow of
the medium into the structure is controlled responsive to the
pressure. The pressure can also be used to determine a filling
endpoint. The medium is hardened while the lumen remains supported
by the balloon. The balloon is then removed after the medium
hardens.
Inventors: |
Evans; Michael A.; (Palo
Alto, CA) ; Watanabe; Gwendolyn A.; (Sunnyvale,
CA) ; Lee; Amy; (Sunnyvale, CA) ; Herbowy;
Steven L.; (Palo Alto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nellix, Inc. |
Irvine |
CA |
US |
|
|
Family ID: |
1000005266389 |
Appl. No.: |
17/119884 |
Filed: |
December 11, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15682414 |
Aug 21, 2017 |
10864098 |
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17119884 |
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14537749 |
Nov 10, 2014 |
9737425 |
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15682414 |
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12684074 |
Jan 7, 2010 |
8906084 |
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14537749 |
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11482503 |
Jul 7, 2006 |
7666220 |
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12684074 |
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60696818 |
Jul 7, 2005 |
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60696817 |
Jul 7, 2005 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/82 20130101; A61F
2/958 20130101; A61B 2017/1205 20130101; A61B 17/12136 20130101;
A61B 17/12195 20130101; A61M 2025/0002 20130101; A61F 2220/005
20130101; A61F 2/07 20130101; A61F 2/95 20130101; A61F 2002/065
20130101; A61F 2250/0003 20130101; A61F 2002/077 20130101; A61F
2/06 20130101; A61F 2220/0058 20130101; A61F 2230/005 20130101;
A61F 2/90 20130101; A61F 2002/067 20130101; A61F 2230/0034
20130101; A61B 17/12118 20130101 |
International
Class: |
A61F 2/958 20060101
A61F002/958; A61F 2/06 20060101 A61F002/06; A61B 17/12 20060101
A61B017/12; A61F 2/95 20060101 A61F002/95; A61F 2/07 20060101
A61F002/07; A61F 2/82 20060101 A61F002/82 |
Claims
1. A method for treating an aneurysm in a patient, the method
comprising: positioning a double-walled filling structure across
the aneurysm, the double-walled filling structure comprising an
inner wall and an outer wall; filling the double-walled filling
structure with a filling medium so that the outer wall conforms to
an inside of the aneurysm and the inner wall forms a generally
tubular lumen to provide for blood flow across the aneurysm;
monitoring a first pressure at an interior of the double-walled
filling structure during and/or after filling of the double-walled
filling structure; and monitoring a second pressure between an
outer surface of the double-walled filling structure and a wall of
the aneurism during and/or after filling of the double-walled
filling structure.
2. The method of claim 1, wherein the blood flow directly contacts
a surface of the inner wall, and the double-walled filling
structure substantially fills the aneurysm when filled with the
filling medium.
3. The method of claim 1, further comprising: supporting the
tubular lumen with a support structure during and/or after filling
the double-walled filling structure with the filling medium.
4. The method of claim 1, wherein the first pressure comprises a
filling pressure of the filling medium during filling of the
double-walled filling structure.
5. The method of claim 4, further comprising: determining a
pressure differential between the first pressure and the second
pressure.
6. The method of claim 5, further comprising: determining an end
point of filling of the double-walled filling structure with the
filling medium based on the pressure differential.
7. The method of claim 4, further comprising: controlling a flow
rate of the filling medium during filling of the double-walled
filling structure based on the filling pressure.
8. The method of claim 1, further comprising: controlling filling
of the double-walled filling structure based on the first and
second pressure.
9. The method of claim 1, further comprising: positioning a
pressure monitoring catheter, guidewire or pressure sensing member
placed at an aneurysm site between the double-walled filling
structure and a wall of the aneurysm.
10. The method of claim 1, further comprising: controlling filling
of the double-walled filling structure based on the first
pressure.
11. The method of claim 10, wherein controlling filling is
performed automatically with a metered pump coupled with a
computerized control system.
12. The method of claim 1, further comprising: determining an end
point of filling of the double-walled filling structure based on
the first pressure.
13. The method of claim 12, wherein the end point of filling is
determined in response to the first pressure reaching a selected
threshold pressure corresponding to an increased likelihood of
dissection of the aneurysm.
14. The method of claim 13, wherein the selected threshold pressure
is determined based on a size and shape of the particular aneurysm,
a patient blood pressure, a wall thickness of the aneurysm, and/or
a dimensional, mechanical or morphological characteristic of the
aneurysm.
15. The method of claim 1, wherein the filling medium comprises any
of: a curable two-part material, a polymer, an epoxy, and a liquid
of stable form.
16. The method of claim 1, wherein the filling medium comprises a
curable medium comprising any of: a liquid, a gel, a foam, and a
slurry.
17. A system for treating an aneurysm comprising: a double-walled
filling structure positionable across an aneurysm, the
double-walled filling structure comprising an inner wall and an
outer wall, wherein the inner wall and the outer wall are
configured such that when the double-walled filling structure is
filled with a filling medium, the outer wall conforms to an inside
of the aneurysm and the inner wall forms a generally tubular lumen
to provide for blood flow across the aneurysm; and a pressure
monitoring system having first and second pressure sensors, wherein
the first pressure sensor is in fluid communication with an
interior of the double-walled filling structure, and the second
pressure sensor is disposed on an outer surface of the
double-walled filling structure.
18. The system of claim 17, further comprising: an expandable
support member disposed within the double-walled filling structure
so as to support the generally tubular lumen during and/or after
filling of the double-walled filling structure.
19. The system of claim 17, wherein the first pressure sensor is
disposed between the inner wall and the outer wall.
20. The system of claim 17, further comprising: a tube configured
to deliver the filling medium into the double-walled filling
structure, wherein the tube is coupled to a controller
communicatively coupled with an output of at least one of the first
and second pressure sensors, the controller configured to control
one or both of a flow rate and a filling pressure based on the
output from at least one of the first and second pressure sensors.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] The present application is a Continuation of U.S.
application Ser. No. 15/682,414, filed Aug. 21, 2017, which is a
Continuation of U.S. application Ser. No. 14/537,749 filed Nov. 10,
2014, now U.S. Pat. No. 9,737,425, which is a Continuation of U.S.
application Ser. No. 12/684,074 filed Jan. 7, 2010, now U.S. Pat.
No. 8,906,084, which is a Divisional of U.S. application Ser. No.
11/482,503 filed on Jul. 7, 2006, now U.S. Pat. No. 7,666,220,
which claims the benefit of priority of U.S. Provisional
Application Ser. No. 60/696,818 filed on Jul. 7, 2005, and U.S.
Provisional Application Ser. No. 60/696,817 filed on Jul. 7, 2005;
the full disclosures of which are incorporated herein by reference
in their entirety for all purposes.
[0002] The present application is also related to U.S. patent
application Ser. No. 11/187,471 filed on Jul. 22, 2005, the full
disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0003] Embodiments of the present invention relate generally to
medical apparatuses and methods for treatment. More particularly,
embodiments of the present invention relate to expandable
prostheses and methods for treating abdominal and other
aneurysms.
[0004] 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.
[0005] Embodiments of the present invention are 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.
[0006] Infrarenal aneurysms are the most common, representing about
seventy percent (70%) 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. Most or all present endovascular systems are
also too large (above 12 French) for percutaneous introduction.
[0007] The most common form of aneurysm is "fusiform," wherein 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 are
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.
[0008] 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
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.
[0009] Present endoluminal aortic aneurysm repairs, however, suffer
from a number of limitations. 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 those who are not considered good candidates
for open surgery. Further shortcomings of the present endoluminal
graft systems relate to both deployment and configuration. The
multiple component systems require additional time for introducing
each piece and even more time for assembling the pieces in situ.
Such techniques are not only more time consuming, they are also
more technically challenging, increasing the risk of failure.
Current devices are also 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] For these reasons, it would be desirable to provide improved
methods, systems, and prostheses for the endoluminal treatment of
aortic aneurysms. Such improved methods, systems, and treatments
should preferably provide implanted prostheses which result in
minimal or no endoleaks, resist migration, are relatively easy to
deploy, have a low introduction profile (preferably below 12
French), and can treat most or all aneurysmal configurations,
including short-neck and no-neck aneurysms as well as those with
highly irregular and asymmetric geometries. At least some of these
objectives will be met by the inventions described hereinafter.
Description of the Background Art
[0011] Grafts and endografts having fillable components are
described in U.S. Pat. Nos. 4,641,653; 5,530,528; 5,665,117; and
5,769,882; U.S. Patent Publications 2004/0016997; and PCT
Publications WO 00/51522 and WO 01/66038
BRIEF SUMMARY OF THE INVENTION
[0012] Embodiments of the present invention provides methods,
systems, and prostheses for the endoluminal treatment of aneurysms,
particularly aortic aneurysms including both abdominal aortic
aneurysms (AAA's) and thoracic aortic aneurysms (TAA's). A
prosthesis can comprise double-walled filling structures which are
pre-shaped and otherwise adapted to substantially fill the enlarged
volume of an aneurysm, particularly a fusiform aneurysm, leaving a
lumen in place for blood flow. Many embodiments utilize pressure
monitoring at the aneurysm site to control the filling of the
filling structure and determine endpoints for filling.
[0013] Embodiments of the double-walled filling structures will
thus usually have a generally toroidal structure with an outer
wall, an inner wall, a potential space or volume between the outer
and inner walls to be filled with a filling medium, and a generally
tubular lumen inside of the inner wall which provides the blood
flow lumen after the prosthesis has been deployed. Other shapes are
also contemplated. The shape of the filling structure will be
preferably adapted to conform to the aneurysm being treated. In
some instances, the filling structure can be shaped for the
aneurysmal geometry of a particular patient using imaging and
computer-aided design and fabrication techniques. In other
instances, a family or collection of filling structures will be
developed having different geometries and sizes so that a treating
physician may select a specific filling structure to treat a
particular patient based on the size and geometry of that patient's
aneurysm. In all instances, the outer wall of the filling structure
will conform or be conformable to the inner surface of the aneurysm
being treated. The inner wall of the structure will be aligned with
lumens of the blood vessels on either side of the prosthesis after
the prosthesis has been deployed.
[0014] The filling structures of the prosthesis will usually be
formed from a non-compliant material, such as parylene, Dacron,
PET, PTFE, a compliant material, such as silicone, polyurethane,
latex, or combinations thereof. Usually, it will be preferred to
form at least the outer wall partially or entirely from a
non-compliant material to enhance conformance of the outer wall to
the inner surface of the aneurysm. This is particularly true when
the aneurysm has been individually designed and/or sized for the
patient being treated.
[0015] The walls of the filling structures may consist of a single
layer or may comprise multiple layers which are laminated or
otherwise formed together. Different layers may comprise different
materials, including both compliant and/or non-compliant materials.
The structure walls may also be reinforced in various ways,
including braid reinforcement layers, filament reinforcement
layers, and the like. In some instances, it would be possible to
include self-expanding scaffolds within the filling structures so
that the structures could be initially delivered and be allowed to
self-expand at the treatment site, thus obviating the need for an
expansion delivery catheter as described as the preferred
embodiment below.
[0016] Preferred delivery protocols will utilize delivery catheters
having a balloon or other expandable support for carrying the
filling structure. When using balloons, the balloons will
preferably be substantially or entirely compliant, although
non-compliant and combination compliant/non-compliant balloons may
also find use. The balloon or other mechanical expansion components
of the delivery catheter will initially be disposed within the
inner tubular lumen of the filling structure, with the filling
structure generally being collapsed into a low width or low profile
configuration over the expansion element. The delivery catheter may
then be introduced intraluminally, typically into the iliac artery
and upwardly to the region within the aorta to be treated. The
delivery catheter will also include one or more lumens, tubes, or
other components or structures for delivering the filling medium in
a fluid form to an internal filling cavity of the filling
structure. Thus, the delivery catheter can be used to both
initially place and locate the filling structure of the prosthesis
at the aneurysmal site. Once at the aneurysmal site, the internal
tubular lumen of the structure can be expanded using the balloon or
other expandable element on the delivery catheter. The filling
structure itself will be filled and expanded by delivering the
filling medium via the catheter into the internal volume of the
filling structure. Both expansion and filling operations may be
performed simultaneously, or can be performed in either order,
i.e., the filling structure may be filled first with the delivery
catheter balloon being expanded second, or vice versa. The filling
structure(s) and/or delivery balloons may have radio-opaque markers
to facilitate placement and/or pressure sensors for monitoring
filling and inflation pressures during deployment.
[0017] In preferred embodiments of the invention, pressure
monitoring can be performed at various stages of the aneurysm
repair procedure to help control the filling process of the filling
structure. The monitoring of pressures serves to reduce the risk of
dissection or damage to the aneurysm from over-pressurization and
also can be used to determine an endpoint for filling. Monitoring
can be done before during or after filling and hardening of the
filling structure with filling medium. Specific pressures which can
be monitored include the pressure within the internal space of the
filling structure as well as the pressure in the space between the
external walls of the filling structure and the inner wall of the
aneurysm. A composite measurement can also be made combining
pressures such as those measured within the interior space of the
filling structure, together with that measured in the space between
the external walls of the structure and the aneurysm wall or other
space at the aneurysm site and an external delivery pressure used
by a fluid delivery device, such as a pump, to deliver the filling
medium Control decisions can be made using any one of these
pressure or a combination thereof.
[0018] Pressures can be measured using a number of pressure sensing
means known in the art including pressure sensors placed on the
interior or exterior of the filling structure as well as a pressure
monitoring catheter, guidewire, or other pressure sensing member
placed at the aneurysm site between the structure and the aneurysm
wall. The pressure sensing means can in turn be coupled to a
pressure monitoring means such as a gauge, electronic pressure
monitor, computer, or the like. A signal from the pressure
sensor(s) can be inputted to a pressure monitoring and control
device such as computer which can utilize the signal in algorithm
to control the flow rate and pressure of a pump or other coupled
the fluid delivery device used to deliver the filling medium.
Pressures can be monitored so as to stay below a selected threshold
pressure which may result in an increased likelihood of dissection
of the aneurysm wall due to pressure forces exerted on the wall
from the pressure exerted by the filling structure during filling.
The threshold pressure can be determined based on the size and
shape of the particular aneurysm, the patient blood pressure, the
wall thickness of the aneurysm and other dimensional, mechanical
and morphological characteristics of the aneurysm site. In
particular embodiments the Law of Laplace can be employed to
determine the forces which will be exerted on the arterial wall for
a given filling pressure. The pressures can also be monitored to
stay below a threshold rate or pressure increase.
[0019] In many embodiments, the monitored pressures can be used to
control one or both of the flow rate and filling pressure of
filling medium into the filling structure. Control can be effected
manually using a syringe or automatically using a metered pump or
other fluid delivery device which is coupled to a controlling
computer or other control system. For example, flow rates can be
decreased or stopped when the pressure or a rate of pressure
increase reaches a threshold value either in the interior or
exterior of the filling structure. Also pressure monitoring can be
used to determine an endpoint for the delivery of the filling
medium. An endpoint decision can be determined based on reaching a
particular pressure value for the interior and/or exterior space of
the filling structure. Endpoint can also be determined by combining
a measured pressure (d) together with a delivered volume of medium,
and imaging observations on the size and shape of the expanded
filling structure. For example, an endpoint can be reached when a
factorial value of pressure and volume has been reached. In this
way, an endpoint decision can be made using a multi-parameter
analysis to provide a more comprehensive determination for knowing
on the one hand when the filling structure is adequately filled and
on other assuring that it is not over-pressurized. Also in related
embodiments, pressure monitoring can be used to titrate the total
delivery of medium into the filling structure.
[0020] In preferred aspects of the present invention, the filling
structure will be filled with a fluid (prior to hardening as
described herein below) at a pressure which is lower than that of
the expansion force provided by the delivery catheter, typically
the filling pressure of the expandable balloon. Typically, the
filling structure will be filled with filling medium at a pressure
from 80 mm of Hg to 1000 mm of Hg, preferably from 200 mm of Hg to
600 mm of Hg, while the delivery balloon is inflated to a pressure
in the range from 100 mm of Hg to 5000 mm of Hg, preferably from
400 mm of Hg to 1000 mm of Hg. These pressures are gage pressures,
i.e., pressures measured relative to atmospheric pressure. As is
descried herein in many embodiments, the pressure within or
external the double-walled structure will be monitored and compared
to a maximum or other value of the patient's blood pressure. In
such cases, the filling pressure can be titrated so as to stay
below a threshold pressure relative to the patient's blood
pressure, for example 90%, 100%, 110%, 150%, 200%, 250%, or 300% of
the patient's maximum blood pressure (or other pressure value). In
this way, real time pressure monitoring can be used to reduce the
likelihood of vessel dissection caused by over-pressurization of
the aneurysm from the pressure exerted by the filling structure
during filling.
[0021] As described thus far, embodiments of the invention
contemplate delivery of a single prosthesis and filling structure
to an aneurysm. Delivery of a single filling structure will be
particularly suitable for aneurysms which are remote from a vessel
bifurcation so that both ends of the filling structure are in
communication with only a single blood vessel lumen. In the case of
aneurysms located adjacent a vessel bifurcation, such as infrarenal
abdominal aortic aneurysms, it will often be preferable to utilize
two such filling structures introduced in a generally adjacent,
parallel fashion within the aneurysmal volume. In the specific case
of the infrarenal aneurysms, each prosthesis will usually be
delivered separately, one through each of the two iliac arteries.
After locating the filling structures of the prosthesis within the
aneurysmal space, they can be filled simultaneously or sequentially
to fill and occupy the entire aneurysmal volume, leaving a pair of
blood flow lumens. Pressure monitoring can be done before, during
or after the filling of one or both filling structures. Threshold
pressure can also be adjusted accordingly (e.g., up or down) for
the use of two filling structures. Also, adjustments can be made
for the effect of filling one filling structure on the measured
pressure in the interior space of the other.
[0022] Suitable materials for the fluid filling medium (also
described herein as filling material) will be fluid initially to
permit delivery through the delivery catheter and will be curable
or otherwise hardenable so that, once in place, the filling
structure can be given a final shape which will remain after the
delivery catheter is removed. The fillable materials will usually
be curable polymers which, after curing, will have a fixed shape
with a shore hardness typically in the range from 10 durometer to
140 durometer. The polymers may be delivered as liquids, gels,
foams, slurries, or the like. In some instances, the polymers may
be epoxies or other curable two-part systems. In other instances,
the polymer may comprise a single material which when exposed to
the vascular environment within the filling structure changes state
over time, typically from zero to ten minutes. In still other
instances, the filling medium need not be hardenable/curable but
may remain liquid and can have rheological properties configured to
mimic blood or native tissue. Such mediums can include various
silicone and collagen solutions known in the art.
[0023] In a preferred aspect of the present invention, after
curing, the filling material will have a specific gravity,
typically in the range from 0.1 to 5, more typically from 0.8 to
1.2 which is generally the same as blood or thrombus. The filling
material may also include bulking and other agents to modify
density, viscosity, mechanical characteristics or the like,
including microspheres, fibers, powders, gasses, radiopaque
materials, drugs, and the like. Exemplary filling materials include
polyurethanes, collagen, polyethylene glycols, microspheres, and
the like.
[0024] Preferably, the filling structures of the prosthesis will
require no additional sealing or anchoring means for holding them
in place within the aneurysm. In some instances, however, it may be
desirable to employ such additional sealing or anchoring
mechanisms, such as stents, scaffolds, hooks, barbs, sealing cuffs,
and the like. For sealing cuffs or stents which extend proximately
of infrarenal prosthesis, it may be desirable to provide openings
or ports to allow the anchoring or sealing devices to extend over
the renal ostia while penetrating blood flow into the renal
arteries. The sealing or anchoring devices will typically be
attached to and/or overlap with the filling structure of the
prosthesis and will provide for a smooth transition from the aortic
and/or iliac lumens into the tubular lumens provided by the
deployed filling structures.
[0025] The filling structures may be modified in a variety of other
ways within the scope of the present invention. For example, the
external surfaces of the filling structures may be partially or
entirely modified to enhance placement within the aneurysmal space,
typically by promoting tissue ingrowth or mechanically interlocking
with the inner surface of the aneurysm. Such surface modifications
include surface roughening, surface stippling, surface flocking,
fibers disposed over the surface, foam layers disposed over the
surface, rings, and the like. It is also possible to provide
biologically active substances over all or a portion of the
external surface of the filling structure, such as thrombogenic
substances, tissue growth promotants, biological adhesives, and the
like. It would further be possible to provide synthetic adhesives,
such as polyacrylamides, over the surface to enhance adherence.
Also the surface of the structure can be coated with one or more
antibiotics to reduce the risk of post-implant infection.
[0026] In some instances, it will be desirable to modify all or a
portion of the internal surface of the filling cavity of the
filling structure. Such surface modifications may comprise surface
roughening, rings, stipples, flocking, foam layers, fibers,
adhesives, and the like. The purpose of such surface modification
will usually be to enhance the filling and bonding to the filling
material, and to control the minimum wall thickness when the
structure is filled particularly after the filling material has
been cured. In particular instances, in locations of the filling
structure which will be pressed together when the structure is
deployed, thus potentially excluding filling material, it will be
desirable if the surfaces of the filling structure can adhere
directly to each other.
[0027] In view of the above general descriptions of the present
invention, the following specific embodiments may be better
understood. In a first specific embodiment, methods for treating an
aneurysm comprise positioning at least one double-walled filling
structure across the aneurysm. By "across" the aneurysms, it is
meant generally that the filling structure will extend axially from
one anatomical location, which has been identified by imaging or
otherwise as the beginning of the aneurysm to a space-part location
(or locations in the case of bifurcated aneurysm) where it has been
established that the aneurysm ends. After positioning, the at least
one filling structure is filled with a fluid filling medium so that
an outer wall of the structure conforms to the inside of the
aneurysm and an inner wall of the structure forms a generally
tubular lumen to provide for blood flow after the filling structure
has been deployed. The tubular lumen will preferably be supported
by a support structure, typically a balloon or mechanically
expansible element, while the filling structure is being filled,
after the filling structure has been filled, or during both
periods. The pressure exerted by the medium within or external the
filling structure can be monitored using a pressure sensing means
such as a pressure sensor positioned on the interior or exterior of
the filling structure. The pressure sensors can include various
solid state and MEMS-based sensors known in the art and can be
configured to provide pressure monitoring both during and after the
filling procedure. The pressure sensing means can also comprise a
pressure monitoring catheter, guidewire or other pressure sensing
member positioned at the aneurysm site between the filling
structure and the aneurysm wall. The pressure sensing member is
desirably configured to be advanceable to the aneurysm site from
the point of arterial or venous access. It can have a pressure
sensing lumen for fluid communication with a pressures sensing
device, or it can have one or more pressure sensors positioned at
it distal tip. The pressure sensing member can be configured to
also be advanced into the interior of the filling structure from a
lumen in the delivery catheter. In particular embodiments, two or
more pressure sensing members can be used and positioned at
different locations in or around the aneurysm site to provide for
differential pressure measurements.
[0028] The monitored pressure(s) can be used to control the flow
rate of filling medium into filling structure and the filling
pressure exerted by a syringe pump or other fluid delivery device.
It can be also used to determine an endpoint for filling of the
filling structure. Filling can be stopped or deceased when the
monitored pressure exceeds a particular threshold. The threshold
can be established by comparison to a measurement of the patient's
blood pressure such as their maximum systolic pressure. For
example, filling can be slowed or stopped when a monitored pressure
is in the range of 100 to 140% of the maximum blood pressure with a
specific embodiment of 110%. Also, similar to pressure monitoring,
the volume of delivered filling medium can be monitored and used to
control the filling medium flow rate as well as endpoint either
independently or in combination with pressure measurement.
[0029] In various embodiments, filling can also be controlled by
means of a valve coupled to the filling structure either directly
or to a filling tube coupled to filling structure. In one
embodiment, the valve can be configured as a mechanical pressure
relief valve to open and relieve pressure from an interior of the
structure when a threshold pressure has been reached. In another
embodiment the valve can be an electronically controlled valve
which either opens to relieve pressure within the filling structure
when the threshold pressure is reached or closes to prevent the
influx of additional filling medium. In the former case, the valve
can be coupled to an exterior wall of the filling structure and in
the latter case it can be coupled to a filling tube or other
filling member used to fill the filling structure. The valve can be
controlled responsive to a pressure signal directly or indirectly
from the pressure sensing means, such as an electronic signal from
a solid state pressure sensor.
[0030] After the filling structure has been filled, the filling
material or medium is hardened while the tubular lumen remains
supported so as to make a formed tubular lumen. Supporting the
tubular lumen during hardening assures that the formed lumen will
have a desired geometry, will properly align with adjacent vascular
lumens, and that the tubular lumen being formed remains aligned
with the native aortic and/or iliac artery lumens after the
prosthesis has been fully implanted. Preferably, the support will
be provided by a balloon which extends proximally (upstream) and
distally (downstream) out of the filling structure where the
balloon may slightly "over-expand" in order to assure the desired
smooth transition and conformance of the tubular lumen provided by
the filling structure with the native vessel lumens. In particular
embodiments, the balloon can have a dog bone or similar shape such
that the proximal and distal portions of the balloon are flared
outwards or otherwise have a larger diameter than the central
portion of the balloon. The ends of the inflated balloon extend at
least partially out of the filling structure. This configuration
serves to shape the lumen of the cured filling structure such that
the proximal and distal ends of the formed lumen flare out relative
to the central portion. This shape serves to provide a smooth
transition in diameter from the native vessel to the formed lumen
and in particular minimizes the surface of the area of the formed
lumen that is normal to the direction of blood flow through artery.
This later configuration serves to minimize an amount of sheer
stress on the formed and adjacent native lumens as well as reduce
an amount of retrograde flow and turbulence in vessel regions
within and adjacent the prosthesis. These fluid dynamic factors
serve to reduce the likelihood of the formation of stenosis in the
region of the prosthetic.
[0031] After hardening, the support will be removed, leaving the
filling structure in place. In some cases, a drain device will be
left in place at the aneurysm site external to the filling
structure to provide for the post implant draining of blood or
other fluids located in the space between the aneurysm wall and the
filled filling structure as discussed below. A porous portion of
the device can be attached to an external surface of the filling
structure to serve as a fluid inlet and another portion such as a
drain tube may be positioned within the new or native arterial
lumen to serve as a fluid outlet. Desirably, the tube portion only
slightly extends into the native lumen and is positioned closely to
the lumen wall to minimize contact areas with flowing blood. The
tube portion can also be configured to be detachable by means of a
guidewire, catheter, or other minimally invasive method. This
allows the physician to remove the tube portion at a selected time
period post implant (e.g., two weeks) at which time it is no longer
needed. The porous portion can include a plurality of apertures,
can be wrapped helically or otherwise around the perimeter of the
filling structure to provide for multiple points of fluid entry.
Desirably the drain device is constructed from non-thrombogenic
biomaterials such as expanded PTFE so as to maintain patency of the
drain. It can also be constructed from re-absorbable biomaterials
known in the art which provide a drain function for a selected time
period before being reabsorbed by the body. In some instances,
however, prior to hardening, it will be desirable to confirm proper
placement of the filling structure. This can be done using imaging
techniques or otherwise testing for patency and continuity.
[0032] In some cases, it may be desirable to first fill the filling
structure with saline or other non-hardenable substance to make
sure that the geometry and size of the filling structure are
appropriate for the particular aneurysm. The fit of the filling
structure within the aneurysm can be checked by imaging methods and
the volume of saline can be adjusted accordingly to produce a
desired fit. For example the physician can check to see if the
filling structure has filled in the entire aneurysm space or if
there any gaps remaining. This can be facilitated by the use of
contrast agents added to the saline or other non-hardenable filling
solution. The volume of saline or other fluid which produces the
desired fit can then be noted. After testing, the saline may be
removed and replaced with an equal or substantially equal volume of
hardenable filler and the remainder of the procedure followed as
described above and herein. In use, these and related embodiments
provide the physician with a means for improving and assuring the
fit of the prosthesis at the aneurysm site before committing to the
procedure. This results in improved clinical outcomes and reduced
incidence of morbidity and mortality due to an improperly fit
prosthesis.
[0033] Various embodiments of the invention also provide means and
methods for draining of blood (and other fluids) located between
the exterior walls of the filling structure and the inner walls of
the aneurysm. Such methods reduce the pressure exerted on the
aneurysms walls during the filling procedure and provide for the
draining of blood or other fluids which remain after the completion
of the procedure. Several different approaches may be employed. In
one approach, the support balloon or other mechanical support
member are shaped so as to not form a seal with the artery wall
(when expanded) and thus allow blood to flow around the
balloon/expansion device at desirably both the proximal and distal
ends of the device. This allows any blood located between the
filling device and aneurysm wall to readily flow out or be
squeegeed out from the aneurysms site as the filling structure is
expanded. In specific embodiments the balloon can have a
multi-lobed cross sectional profile which allows blood to flow in
the valleys between the lobes while peaks of the lobes provide
support to maintain the tubular shape of the inner lumen of the
filling member. In one embodiment, the balloon can have a three
lobe structure. In other embodiments, the balloon support member
can comprise a multi-balloon member, for example, a three balloon
member that allows for blood flow in the spaces between the
balloons. In other embodiments, an expandable shape memory stent
can be used that allows for blood flow through the stent. In
another, expandable basket-like structures can be used. The
expandable basket-like structures have a series of spring memory
splines or other spring member to hold the lumen open, but still
allows blood flow around and through the splines. The stent or
basket can have a deployed and non-deployed state. The stent or
basket can be deployed either through the application of tension or
compression which can be applied, for example, by the delivery
catheter or guide wire. Other structures having spring memory
materials which can be mechanically engaged to a deployed state to
support the inner lumen can also be used. These and related
embodiments not only provide for the outflow of blood located
between the aneurysm wall and the filling structure, but also for
the normal flow of blood through the entire length of the aneurysm
site so as to maintain adequate perfusion of organs and tissue
downstream from the aneurysm site. Such perfusion can also be
achieved or supplemented by the use of a perfusion lumen and
proximal and distal apertures in the delivery catheter which allows
blood to flow through the delivery catheter when the balloon is
inflated during filling of the filling structure. In other
embodiments allowing perfusion, the filling structure can comprise
a continuously coiled structure that has an open central lumen for
blood flow which does not need support during filling, or a series
of inner tube like structures that are joined and also do not need
to be supported during filling to maintain patency of the central
lumen.
[0034] In another approach for draining blood from the aneurysm
site, a drain device can be positioned on or nearby the exterior
outer wall of the filling structure. The drain can be configured to
be removed after the completion of the filling procedure or left in
place to provide for post implant draining of the aneurysm site as
is discussed below. The drain will typically have a porous inflow
portion and a tube outflow portion. The porous portion allows for
the inflow of blood from an aneurysm site. The tube portion extends
downstream or upstream from aneurysm site into the native vessel
lumen and provides for the outflow of blood. The tube portion can
be configured to extend a selectable length into the native lumen.
Preferably for post implant draining, the tube portion is
configured to only slightly extend into the lumen of the native
vessel and is configured to be located close to the lumen wall
(e.g., several millimeters) to minimize contact area with flowing
blood. It can be coupled to a catheter as discussed below.
[0035] The porous portion can include a plurality of apertures
which allows for the inflow of blood from multiple locations and
also provides redundancy should one or more of the apertures become
blocked with thrombus or other matter. The porous portion can be
helically or otherwise wrapped around all or a portion of the
perimeter of the filling structure exterior. Helically wrapping
allows for the inflow of blood from multiple locations around the
filling structure and thus serves to produce more uniform draining
of blood or other fluid. In particular embodiments, the porous
portion can also comprise a plurality of arms which are
longitudinally or otherwise distributed around the perimeter of the
filling structure. The porous portion can be attached to the
filling structure with an adhesive, sonic weld, or held in place by
tension.
[0036] In many embodiments, the drain device is configured to
provide a passive draining function based from the pressure exerted
by blood or other fluid constrained between the filling structure
and the inner walls of the filling aneurysm. In other embodiments,
the drain can be configured to be coupled to a vacuum so as to
provide active draining by a vacuum force. Vacuum application to
remove blood can be done at any selected time during the repair
procedure, including during or after filling of the filling
structure. In some embodiments, blood can be withdrawn concurrently
to the injection of filling medium into the filling structure so as
to control the pressure exerted by the filling medium on the
aneurysm wall. In particular embodiments, a substantially equal
volume of blood can be withdrawn from the aneurysm site as the
volume of medium is injected into the filling structure. The
withdrawal and injection can be done simultaneously or near
simultaneously and substantially at the same rate using concurrent
injection and withdrawal means known in the art. Pressures can be
monitored continuously during this operation and the withdrawal
rate and/or injection rate can be adjusted accordingly to maintain
pressure below a threshold or other set point.
[0037] Vacuum application can be achieved by coupling the tube or
end portion of the drain to a dedicated lumen of the delivery
catheter which is in turn connected to a vacuum source.
Alternatively, the drain device can be attached to a separate
catheter for providing a dedicated source of vacuum pressure. This
latter configuration also provides a means for placement and
removal of the drain device independent from positioning of the
delivery catheter.
[0038] In still other approaches, a drain function can be provided
by means of a needle which is inserted into the aneurysm site by a
laparoscopic approach or other method. A vacuum can then be pulled
on the needle using a syringe or other vacuum source. In a related
approach, draining can be done using a pressure sensing member such
as catheter or guide wire discussed herein which is appropriately
positioned in the aneurysm site. The pressure sensing member can
provide for both passive draining or active draining through the
application of vacuum pressure to the pressure monitoring lumen of
the catheter or guide wire. The lumen dimension can be sized to
provide for both pressure monitoring and blood/fluid removal
functions. The pressure sensing member can also be used to
supplement the draining function of a primary draining device as
well as reach particular locations between the aneurysm wall and
filling structure that require additional draining or are otherwise
inaccessible to the primary drain device. This function can be
achieved by configuring the pressure sensing member to be steerable
using various catheter/guidewire fabrication techniques known in
the art.
[0039] In a second specific embodiment of the present invention,
abdominal aortic aneurysms and other bifurcated aneurysms are
treated by positioning first and second double-walled filling
structures within the aneurysmal volume. The first and second
double-walled filling structures are positioned across the
aneurysm, as defined above, extending from the aorta beneath the
renal arteries to each of the iliac arteries, respectively. The
first fluid filling structure is filled with a fluid filling
material, the second filling structure is also filled with a fluid
material, and the outer walls of each filling structure will
conform to the inside surface of the aneurysm as well as to each
other, thus providing a pair of tubular lumens for blood flow from
the aorta to each of the iliac arteries. Preferably, the tubular
lumens of each of the first and second filling structures are
supported while they are being filled or after they have been
filled. Still further preferably, the tubular lumens will remain
supported while the filling material is hardened, thus assuring
that the transitions to the tubular lumens to the native vessel
lumens remain properly aligned and conformed.
[0040] In a third specific embodiment of the present invention,
systems for treating aneurysms comprise at least one double-walled
filling structure and at least one delivery catheter having an
expandable support positionable within a tubular lumen of the
filling structure. The systems will usually further comprise a
suitable hardenable or curable fluid filling medium The particular
characteristics of the filling structure and delivery balloon have
been described above in connection with the methods of the present
invention.
[0041] In a still further specific embodiment of the present
invention, a system for treating abdominal aortic aneurysms
comprises a first double-walled filling structure and a second
double-walled filling structure. The first and second filling
structures are adapted to be filled with a hardenable filling
medium while they lie adjacent to each other within the aneurysm.
The systems further comprise first and second delivery catheters
which can be utilized for aligning each of the first and second
filling structures properly with the right and left iliacs and the
infrarenal aorta as they are being deployed, filled, and
hardened.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1A illustrates a single prosthesis system comprising a
filling structure mounted over a delivery catheter.
[0043] FIG. 1B illustrates a single prosthesis system including a
pressure monitoring system for monitoring pressure during an
aneurysm repair procedure using a fillable prosthetic implant.
[0044] FIGS. 1C-E illustrate use of a pressure monitoring system
during an aneurysm repair procedure using a fillable prosthetic
implant.
[0045] FIG. 2 is a cross-sectional view of the filling structure of
FIG. 1A illustrating various surface modifications and a filling
valve.
[0046] FIGS. 3A-3C illustrate alternative wall structures for the
filling structure.
[0047] FIG. 4 illustrates the anatomy of an infrarenal abdominal
aortic aneurysm.
[0048] FIGS. 5A-5D illustrate use of the prosthesis system of FIG.
1 for treating the infrarenal abdominal aortic aneurysm
[0049] FIG. 6 illustrates a system in accordance with the
principles of the present invention comprising a pair of prosthesis
for delivery to an infrarenal abdominal aortic aneurysm, where each
prosthesis comprises a filling structure mounted on a delivery
catheter.
[0050] FIGS. 7A-7F illustrate use of the prosthesis system of FIG.
6 for treating an infrarenal abdominal aortic aneurysm.
[0051] FIGS. 8A-8D illustrate use and placement of a drain device
with embodiments of the prosthesis system
[0052] FIGS. 9A-9F illustrate different embodiments of a drain
device for use with embodiments of the prosthesis system FIG. 9A
shows a porous portion of a drain device positioned in vessel space
US, FIG. 9B shows a drain device with a porous portion positioned
in space US coupled to a vacuum source for active draining, FIG. 9C
shows a drain device having a helically wrapped porous portion,
FIG. 9D shows a drain device having a plurality of porous arms
defining a drainage geometry, FIG. 9E is a detailed view of a
single arm of the embodiment of FIG. 9 D, FIG. 9 F shows an
embodiment of a drain device comprising a needle.
[0053] FIG. 10 illustrates a method for the concurrent removal of
blood from the aneurysm site and filling medium injection into the
filling structure.
[0054] FIGS. 11A-B are lateral and cross sectional views
illustrating embodiments of an inflatable multi-lobe support member
that allows for the drainage of blood from the aneurysm site during
inflation
[0055] FIGS. 12A-B are lateral and cross sectional views
illustrating embodiments of a multi-balloon support member that
allows for the drainage of blood from the aneurysm site during
inflation.
[0056] FIGS. 13A-B illustrate the use of an embodiment of a multi
balloon support member to allow the drainage of blood from the
aneurysm site during inflation
[0057] FIG. 14A is a perspective view illustrating an embodiment of
an expandable stent support member that allows for the drainage of
blood from the aneurysm site during inflation in the non-expanded
state.
[0058] FIG. 14B is a perspective view illustrating an embodiment of
an expandable stent support member that allows for the drainage of
blood from the aneurysm site during inflation in the expanded
state.
[0059] FIG. 14C illustrates use of the expandable stent structure
to allow the drainage of blood from the aneurysm site during
expansion.
[0060] FIGS. 15A-C are perspective views illustrating embodiments
of an expandable basket support member that allows for the drainage
of blood from the aneurysm site during inflation. 15A is in the
non-expanded state, 15B is partially expanded and 15C is in the
fully expanded state.
[0061] FIGS. 16A-B are perspective views illustrating embodiments
of another expandable support member that allows for the drainage
of blood from the aneurysm site during inflation. 16A is in the
non-expanded state and 16 B is in the expanded state.
[0062] FIGS. 17A-C are perspective, lateral and cross sectional
views illustrating embodiments of a coiled filling structure that
allows for the drainage of blood from the aneurysm site during
filling.
[0063] FIG. 18 is a perspective view of a continuously coiled
helical filling structure.
[0064] FIG. 19 is a perspective view of a continuously coiled
filling structure having a FIG. 8 shape.
[0065] FIGS. 20A-C illustrate use of a continuously coiled filling
structure for repair of an arterial aneurysm.
[0066] FIGS. 21A-21C illustrate use of a pair or continuously
coiled filling structures for repair of an arterial aneurysm near
an arterial bifurcation.
[0067] FIGS. 22A-B are perspective and lateral views illustrating
an embodiments of an inflatable support member having flared end
portions.
[0068] FIG. 22 C illustrates use of the flared support balloon to
produce a filling structure blood flow lumen with flared end
portions.
[0069] FIG. 23 illustrates an embodiment of the prosthesis system
comprising a filling structure mounted over a delivery catheter in
which the delivery catheter includes a perfusion lumen and proximal
and apertures for the perfusion of blood through the lumen during
filling of the filling structure.
DETAILED DESCRIPTION OF THE INVENTION
[0070] Referring now to FIGS. 1A-1D, an embodiment of 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 a support structure 16, at its distal end. Typically,
support structure 16 comprises an expandable element 16 such as
expandable balloon. The support structure can also comprise various
mechanically expandable structures, such mechanically expandable
stents, basket devices and various mechanical structures having
shape or spring memory. 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 or other filling member 20 for delivering a filling medium
or material 23 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. 1A.
[0071] In many embodiments, system 10 includes a pressure
monitoring 60 system so as to be able to measure one or more
pressures at the aneurysm site before, during or after the filling
of filling structure 12. System 60 comprises a pressure sensing
means 61 and a pressure monitoring means 65. Sensing means 61 can
comprise one or more pressure sensors 62 placed in the interior
space 22 of structure 12 so as to measure the filling pressure 69
within the structure, or placed on the external surface of outer
wall 24 so as to measure the pressure the blood pressure in 68 in
vessel space US, which is the space between the surface S of the
aneurysms wall and outer wall 24. The sensor can comprise various
pressures sensor known in the art including various solid state
sensors, MEMS-based sensors, optical sensors and other miniature
pressure sensors known in the art. Also multiple sensors 62 can be
placed on the interior and exterior of the structure so as to
produce a sensor array 62A. The sensors can be coupled to pressure
monitoring means by a cable C or other electrical coupling means
known in the art.
[0072] Sensing means 60 can also include a pressure sensing member
63, which can include a guidewire, catheter or like structure.
Sensing member 63 can comprise a sensor tipped member such as a
sensor tipped catheter, or it can have a lumen 64 for fluid
communication with pressure monitoring means 65, such as an
electronic pressure monitor which itself includes a pressure sensor
such as a strain gauge. Embodiments of the sensing member having a
lumen can also be configured to be used as a drain device 80
discussed herein.
[0073] The sensing member can be configured to be both advanceable
and steerable either through the arterial vasculature or through a
lumen of delivery catheter 14. In particular embodiments, it can be
sized and have mechanical properties to be advanced through
delivery catheter 14 into the interior space 22 of structure 12 so
as to monitor the filling pressure 69 in that space. It can also be
sized and have mechanical properties to be advanced into the
aneurysm site AS including vessel space US from a vascular access
point such as the femoral artery near the groin or the brachial
artery near the arm pit. This allows the member to measure the
blood pressure 68 in space US.
[0074] In many embodiments, system 60 can include two or more
pressure sensing members 63 as is shown in FIG. 1C which can be
positioned at different locations in or around the aneurysm site,
AS. This provides the physician with a more reliable indication of
the pressure over the entire aneurysm site AS; it also provides for
the ability to do differential pressure measurements over a
particular length of the site (e.g. proximal to distal) as well
differential measurements inside and outside of the filling
structure. For example, one sensing member could be positioned in
space 22 within the filling structure and another in vessel space
US. It also allows the physician to spot check particular locations
in vessel space US to determine if there are any areas which have
trapped blood and are rising too fast in pressure. In this way, the
physician can develop a pressure profile or barometric
3-dimensional map of pressure over the entire aneurysm site (both
inside and out of the filling structure) and utilize that map to
monitor and control the filling process and entire aneurysm repair
procedure.
[0075] In various embodiments, pressure monitoring means 65 can
comprise a gauge, a dedicated electronic pressure monitor, a
modular monitor configured to be integrated with other medical
monitoring instrumentation, computer with pressure mentoring
capability, or like device. Typically the monitoring means will
comprise an electronic pressure monitor having a display 66 for
displaying a pressure waveform 67 and/or a numeric readout. It can
also be configured to have one or more alarms to alert the medical
staff when a pressure threshold has been reached. The monitoring
means can also be integral to or otherwise coupled to a control
system 70 discussed below for controlling the filling rate and
pressure of filling structure 12.
[0076] In various embodiments, one or more of the monitored
pressures at site AS can be used to control the filling process of
structure 12 including both the flow rate of filling medium 23 and
the pressure used to fill the structure by a syringe pump or other
fluid delivery means. This can accomplished by the physician
eyeballing the pressure and making manual adjustments to flow rate
on a syringe pump. It many embodiments, it can be accomplished by
means of a control system 70 which can comprise a computer or
processor 71 coupled to pressure sensing means 60 and a fluid
delivery means 75. Computer 70 can include or be coupled to a
pressure monitoring means 65 which in turn are coupled to pressure
sensing means 60. Computer 70 can receive input signals 75 from
pressuring sensing means 60 and send output signals 76 to fluid
delivery means 75 for the control of the flow rate and delivery
pressure of medium 23 to filling structure 12. Fluid delivery means
can include a syringe pump, peristaltic pump, metered pump, or
other medical pump known in the art. The computer include one or
more modules or control algorithms 72 for controlling flow rate and
pressure of fluid delivery means 75 responsive to input signal 75
from sensor means 60. Modules 72 can include one or more P, P1, or
PID or other control algorithms known in the art. In many
embodiments, modules 72 can be configured to utilize a threshold
pressure, or rate of pressure change to control the filling
process. For example, the module can be configured to slow or stop
the filling rate when a monitored pressure reaches or approaches
the threshold. This threshold can be pre-set by the physician or
can be determined through measurement and comparison to the
patient's blood pressure as is explained below.
[0077] In addition to controlling the filling process, pressure
monitoring, done either manually or through control system 70 can
be utilized to determine an endpoint for filling the filling
structure. Similar to the control of flow rate, the endpoint can be
determined based upon reaching or approaching a pressure threshold
either absolute or a rate of change. Pressure monitoring can be
used to determine the endpoint out right, or in some cases can be
used to titrate or fine tune endpoint determination by coupling
this information together with observation of the deployed size of
the filling structure and total volume of medium delivered.
Computer 71 can be programmed to alert the physician when an
endpoint is approaching based on pressure measurement and then
allow the physician to fine tune the process. The computer can also
be programmed to give the physician a pressure range or window for
making a manual endpoint decision with an ultimate shut off value.
In this way the system affords the physician the ability to fine
tune the endpoint while still providing a fail-safe protection
function to prevent the physician from exceeding a pressure
threshold which may cause dissection or other damage to the
aneurysm wall.
[0078] In various embodiments, filling can also be controlled by
means of a valve 40 coupled to filling structure 12 either directly
or to filling tube 20 as is shown in FIG. 2. In one embodiment, the
valve can be configured as a mechanical pressure relief valve 40r
configured to open and relieve pressure from interior 22 when a
threshold pressure has been reached. In another embodiment the
valve can be an electronically controlled valve 40e which either
opens to relieve pressure within the filling structure when the
threshold pressure is reached or closes to prevent the influx of
additional filling medium In the former case, the valve can be
coupled to an exterior wall of the filling structure and in the
latter case it can be coupled to filling tube 20 or other filling
member used to fill the filling structure. The electronic valve 40e
can be controlled responsive to a pressure signal directly from a
pressure sensor 62, or a signal 77 from control system 70.
[0079] Referring now to FIGS. 1C-E, in various embodiments, the
patient blood pressure can be utilized in determining a pressure
threshold for both controlling the filling process and determining
an endpoint for filling. In one embodiment, sensing system 60 can
be used to measure the patient's blood pressure 68 at the aneurysm
site AS, such as their maximum systolic pressure, before placement
of filling structure 12 as is shown in FIG. 1C. This maximum value
68m then becomes the threshold value that is used for control of
the filling process. Other values can also be used such maximum
diastolic pressure, or maximum time averaged pressure (e.g., over
one minute). One or more filling structures can then be deployed
and filled as shown in FIG. 1D with a pressure sensing member
positioned in the interior 22 of the filling structure to monitor
filling pressure 69. Filling can be completed when the filling
pressure remains at or slightly above maximum pressure 68m, for
example by 10% to 20%. This can also be corroborated by imaging
observation to see if the filling structures are fully inflated
and/or slightly oversized to see that filling structures are
completely filling in the aneurysm. In a different approach shown
in FIG. 1E, filling can be completed based on a measured maximum or
other value of blood pressure in vessel space, US. This measurement
can also be compared to the prior measure maximum value 68m without
the filling structure in place.
[0080] Referring now to FIG. 2, the various internal and external
surfaces may be shaped, coated, treated, or otherwise modified to
provide for a number of particular features in accordance with the
principles of the present invention. For example, the outer wall 24
may be shaped to have rings, stipples, or other surface features
which are typically formed into the material of the structure at
the time of molding, vapor deposition, or other manufacturing
process. The outer surface may also be coated with materials 28
which can be adhesives, drugs, active substances, fibers, flocking,
foams, or a variety of other materials. In most cases, such surface
features or modifications will be intended to enhance sealing or
attachment of the outer wall 24 to the inner surface of the
aneurysm being treated.
[0081] The inner surface 30 of the filling volume 22 may also be
modified by providing features, coatings, surface roughening, or a
variety of other modifications. The purpose of such internal
features is typically to enhance adherence of the walls to the
filling material or medium as the medium is cured or otherwise
hardened. In some instances, materials may be coated on all or a
portion of the inside surface 30 to induce or catalyze hardening of
the filling material as it is being introduced.
[0082] The double-walled filling structure 12 will typically
comprise at least one valve 40 to permit the introduction of the
filling material or medium into the internal volume 22. As
illustrated, the valve 40 may be a simple flap valve. Other more
complex ball valves, and other one-way valve structures may be
provided. In other instances, two-way valve structures may be
provided to permit both filling and selective emptying of the
internal volume 22. In other instances, the filling tube may
comprise a needle or other filling structure to pass through the
valve 40 to permit both filling and removal of filling medium Valve
40 may also be configured as a mechanical pressure release valve
40r configured to open and relieve pressure when the filling in
space 22 exceeds a preset threshold. Such pressure relieve valves
40r can be placed both in supply tube 20 and also in the external
wall 24 of the filling structures. When they open, such valves
allow filling medium to exit the filling structure when placed in
wall 24 or divert it from entering in the first place when placed
in supply tube 20. Valve 40 can also be an electronically
controlled valve 40e configured to shut off in response to a signal
from a pressure control system 70, or directly from a pressure
sensor 62 described herein so as to stop the inflow of medium 23
when the pressure in space 22 exceeds a threshold.
[0083] As illustrated in FIG. 2, the wall structure of the
double-walled filling structure may be a single layer, typically
molded or otherwise conventionally formed. The wall structures may
also be more complex, for example, as illustrated by FIGS. 3A-3C.
FIG. 3A shows a multi-layered wall comprising layers 42, 43, and
44. It will be appreciated that such multiple layer structure can
provide for increased strength, puncture resistance, variations in
compliance, and/or flexibility, differences in resistance to
degradation, and the like. As shown in FIG. 3B, a single wall or
multiple wall structure can be reinforced by braid, coils, or other
metal or non-polymeric reinforcement layers or structures. As shown
in FIG. 3C, the external surface 24 of the wall may be covered with
drugs, fibers, protrusions, holes, active agents, or other
substances for a variety of purposes.
[0084] Referring now to FIG. 4, 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).
[0085] Referring to FIGS. 5A-5D, the treatment system 10 of FIG. 1
may be utilized to treat the complex geometry of the transmural
abdominal aortic aneurysm (AAA) of FIG. 4 by first positioning the
delivery catheter 14 to place the double-walled filling structure
12 (in its unfilled configuration) generally across the aneurysm
from the region of the aorta beneath the renal arteries (RA) to a
region over the iliac arteries (IA), as best seen in FIG. 5A.
Usually, the delivery catheter 14 will be introduced over a
guidewire (GW) through a puncture in the patient's groin accessing
the iliac artery by the Seldinger technique.
[0086] After the double-walled filling structure 12 is properly
positioned, a hardenable inflation medium is introduced into the
internal space 22. Filling of the inner space 22 then expands the
outer wall 24 of the structure outwardly so that it conforms to the
inner surface (S) of the aneurysmal space.
[0087] Before, during, or after filling of the double-walled
filling structure 12 with inflation medium, as illustrated in FIG.
5B, the balloon 16 or other expansible structure will also be
inflated or expanded to open the tubular lumen defined by the
interior of the inner wall 26. In a preferred embodiment, the
balloon 16 will be generally non-compliant, typically having a
maximum diameter of width which is at or slightly larger than the
desired tubular lumen diameter or width through the deployed
filling structure 12. The filling structure 12, in contrast, will
be partially or completely formed from a generally compliant
material, thus allowing the non-compliant balloon or other
expansible structure 16 to fully open the tubular lumen and conform
to the ends of the lumens to the aorta and iliac walls, as
illustrated in FIG. 5C. A lower or proximal end 50 of the tubular
lumen will be flared to a larger diameter so that it can
accommodate the openings of both the iliac arteries (IA) as
illustrated. Thus, it will be preferred to utilize a filling
structure 12 geometry which has been chosen or fabricated to match
the particular patient geometry being treated. It will also be
preferable to use a balloon 16 or other expansible structure which
will be shaped to preferentially open the lower proximal end 50 of
the tubular lumen to a larger diameter than the upper or distal end
52.
[0088] After the filling material has been introduced to the
filling structure 12, typically through the filling tube 20, the
fluid filling material can be cured or otherwise hardened to
provide for the permanent implant having a generally fixed
structure which will remain in place in the particular aneurysmal
geometry. Pressure monitoring can be performed during all or a
portion of the hardening period and can be used to determine an
amount or endpoint of hardening. Methods for curing or hardening
the filling material will depend on the nature of the filling
material. For example, certain polymers may be cured by the
application of energy, such as heat energy or ultraviolet light.
Heat energy can be applied using various energy delivery means
including RF, ultrasonic and infrared delivery means. Other
polymers may be cured when exposed to body temperature, oxygen, or
other conditions which cause polymerization of the fluid filling
material. Still others may be mixed immediately prior to use and
simply cured after a fixed time, typically minutes. Often, after
the filling material has been hardened, the delivery catheter 12
may be removed and the filling structure left in place as the
completed prosthetic implant. The pressure sensing and/or drain
device (discussed herein) can also be removed at this time or left
in place for a selected period. In still other embodiments, the
filling medium need not be hardenable/curable but rather has
rheological properties configured to mimic blood or native tissue.
Such mediums can include various silicone solutions known in the
art.
[0089] In other cases, however, it may be desirable to further
position certain seals, anchors, stents, or other additional
prosthetic components at either the proximal end 52 or distal end
50 of the graft. As illustrated in FIG. 5D, for example, a
stent-like structure may be planted in the upper proximal opening
52 of the tubular lumen of the filling structure 12 in order to
help anchor the structure, help prevent intrusion of blood into the
region between the outer wall 24 and inner surface (S) of the
aneurysm, and to generally improve the transition from the aorta
into the tubular lumen. The sealing or anchoring structure may
simply comprise a stent-like component, preferably having a port or
other access route to allow blood flow into the covered renal
arteries (if any). Alternatively, the anchor structure could be
another inflatable unit, such as the anchor described in
co-pending, commonly owned application Ser. No. 10/668,901
(published as US2004/0116997A1), the full disclosure of which is
incorporated herein by reference.
[0090] In a particular and preferred aspect of the present
invention, a pair of double-walled filling structures will be used
to treat infrarenal abdominal aortic aneurysms, instead of only a
single filling structure as illustrated in FIGS. 5A-5C. A system
comprising such a pair of filling structures is illustrated in FIG.
6 which 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. 1. 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. 1 is that the pair of filling structures will
generally have asymmetric configurations which are meant to be
positioned adjacent to each other within the aneurysmal space and
to in combination fill that space, as will be described with
specific reference to FIG. 7A-7F below.
[0091] In treating an infrarenal abdominal aortic aneurysm using
the pair of filling structures 112 and 212 illustrated in FIG. 6, a
pair of guidewires (GW) will first be introduced, one from each of
the iliac arteries (IA). As illustrated in FIG. 7A, 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. 7B. 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. 7C. 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.
7D where the filling structure 112 and balloon 116 are inflated to
fill generally half of the aneurysmal volume, as illustrated in
FIG. 7D. Filling can generally be carried out as described above
with the one filling structure embodiment, except of course that
the filling structure 112 will be expanded to occupy only about
one-half of the aneurysmal volume. After the first filling
structure 112 has been filled, the second filling structure 212 may
be filled, as illustrated in FIG. 7E. 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 arteries
(IA).
[0092] After filling the filling structures 112 and 212 as
illustrated in FIG. 7E, the filling materials or medium will be
cured or otherwise hardened, and the delivery catheters 114 and 214
removed, respectively. The hardened filling structures will then
provide a pair of tubular lumens opening from the aorta beneath the
beneath the renal arteries to the right and left iliac arteries, as
shown in broken line in FIG. 7. The ability of the filling
structures 112 and 212 to conform to the inner surface (S) of the
aneurysm, as shown in FIG. 7F, helps to assure that the structures
will 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 above in connection with the embodiments of FIG. 2.
Optionally, and not illustrated, anchoring or sealing structures
could be provided in either of the upper or proximal openings of
the tubular lumens into the aorta or from either of the distal or
lower openings into the respective iliac arteries.
[0093] Referring now to FIGS. 8A-D, in various embodiments system
10 can include a drain device 80. Drain device 80 provides for the
draining of blood and other fluid from the vessel space (VS)
between the aneurysms wall (AW) and the external surface S of the
filling structure 12. By removing blood or other fluid which may be
trapped in space VS during filling of the filling structure
draining serves to reduce the pressure forces exerted against the
aneurysm wall by the expansion of filing structure and thus reduce
the associated risk of aneurysm dissection or rupture. The device
can be configured to provide for passive draining from the pressure
exerted by blood BD in space VS (as is shown in FIG. 8B) or active
draining from a vacuum source 87 such as a syringe (as is shown in
FIGS. 5C and 8D). The device can be configured to be temporally or
permanently left in place at site AS
[0094] In many embodiments, the drain device will comprise a
flexible member having an inflow portion 82 to provide for the
inflow of blood BD other fluid and an outflow portion 83 to provide
for the outflow either into adjoining vessels or external to the
patient's body. As shown in FIGS. 9A and 9B, inflow portion 82 can
comprise a porous portion 84 which can have a plurality of
apertures 85 provide for inflow of fluid from multiple locations
over portion 82 and also provides redundancy should one or more of
the apertures become blocked with thrombus or other matter. In one
embodiment shown in FIG. 9C, inflow portion 81 will be helically or
otherwise wrapped around the circumference of structure 12 so as to
define a drainage volume or geometry 88. Various drainage
geometries such as spherical, cylindrical etc., can be defined
based on the positioning of the porous portion around the filling
structures and the shape of the filling structure. Also the pattern
85p and shape of apertures 85 over geometry 88 can be configured to
optimize draining for a particular orientation of the drain. For
example, in cases of downstream passive draining, the more proximal
section of the porous portions can have a greater aperture density
and/or larger diameter apertures. These and related configurations
of the porous portion provides for drainage of blood BD from
multiple locations within space US so as to produce more uniform
draining and minimize the likelihood of blood BD or other fluid
from becoming trapped within a particular location within
space.
[0095] In another embodiment shown in FIGS. 9D and 9E the inflow
portion 82 can comprise a series of arms 84A that are
longitudinally or otherwise distributed around the circumference of
structure 12. All or a portion of each arm can have a porous
portion 84. Arms 84A can also serve to define a drainage volume or
geometry 88. The inflow portion for both the embodiments of FIGS.
9D and 9E can be coupled to structure 12 using various joining
methods known in the art including adhesive or ultrasonic welding,
it can also be held in place by tension and/or frictional forces.
The inflow portion of either embodiment can be configured to
readily detached from structure 12 using e.g., a low force adhesive
to allow the drain to be removed through use of a laparoscopic
instrument. They also need not be attached to the structure but can
exist as separate structure which can be attached to deliver
catheter 14 or can be otherwise removed using a guidewire,
laparoscopic instrument or other means. In various embodiments this
can be facilitated through the use of retrieval element such as a
loop, hook or like structure (not shown) attached to a portion of
the drain device to allow it be retrieved from either an upstream
or downstream approach.
[0096] In an embodiment shown in FIG. 9F drain device 80 can
comprise a needle 89 which is configured to be inserted into vessel
space US by a laparoscopic approach or other method. A vacuum can
then be pulled on the needle using a syringe or other vacuum source
87. This method allows the doctor to easily and quickly remove a
desired volume of blood concurrent to the delivery of filling
medium to structure 12. The doctor can make the withdrawal manually
while monitoring pressure during filling so as to stay below a
select pressure (e.g., 20% above the patient's blood pressure).
Also the withdrawal can be done automatically using a syringe pump.
The rate can be adjusted manually and the pump can be coupled to a
computer/processor having an algorithm that controls the withdrawal
rate based on monitored pressure(s) at site AS.
[0097] Referring now to FIG. 10, in a variation of the above
embodiment, system 10 can be configured to allow for a
substantially equal rate of blood removal from site AS as the flow
rate of filling medium 23 injected into the filling structure 12
(and hence to the total volumes as well). The withdrawal and
injection can be done simultaneously or near simultaneously and at
substantially the same rate using a dual action syringe pump or
other concurrent injection and withdrawal means 75 known in the
art. Pressures can be monitored continuously during this procedure
and the withdrawal rate and/or injection rate can be adjusted
accordingly to maintain pressure below a threshold or other set
point.
[0098] Outflow portion 83 will typically comprise a tube portion 86
(also called tube 86) that can be configured to extended proximally
or distally from site AS into the lumen LN of the native vessels NV
adjoining site AS. The tube can be extended various lengths into
the vessels NV, e.g., several millimeters to several centimeters.
In some embodiments where draining is done passively (as is
discussed herein), the tube 86 will be positioned distally or
downstream from site AS so to allow passive draining of blood due
to the hydrostatic pressure forces exerted by blood or other fluid
in space AS. In other embodiments where draining is done actively
(e.g., from the use of a vacuum), tube 86 can be positioned
proximally relative to site AS. For embodiments where the device is
left in at site AS for post implant draining, the tube is
preferably configured to only slightly extend into lumen LN of the
native vessel and is configured to be located close to be close to
lumen wall (e.g., several millimeters) to minimize contact area
with flowing blood. The tube portion can also be sized to be
connected to a subcutaneous or a cutaneous access device/fluidic
connector or reservoir (not shown) to allow for cutaneous access
and removal of blood.
[0099] Tube portion 86 can also be configured to be detachable from
the remainder of the drain device by means of a guidewire, catheter
or other minimally invasive method. This allows the physician to
remove the tube portion at a selected time period post implant
(e.g., two weeks) at which time it is no longer needed.
Detachability can be achieved through the use of a reliable joint
known in the art or a low force adhesive. Tube portion 86 can also
include a retrieval element discussed herein.
[0100] In still other embodiments, tube portion 86 may be sized to
extend all the way outside of the patient's body through a vascular
access site such as at the groin. This latter embodiment allows for
the draining of blood and fluid both passively and actively by the
application of vacuum. It can also be configured to be fluidly
coupled to a pressure sensing member 65 so as to allow the draining
of blood through the pressure sensing member.
[0101] In various embodiments, drain device 80 can be constructed
from various non-thrombogenic biomaterials known in the art such as
silicone, polyurethane, and the like so as to maintain patency of
both the inflow and the outflow portions. Also, all or a portion of
the drain can have various coatings, for example, non-thrombogenic
coatings such as a heparin based coating to provide additional
thrombogenic protection for various periods of use. In preferred
embodiments it can be constructed from expanded PTFE. Also, all or
a portion of the drain can also be constructed from re-absorbable
biomaterials known in the art so as to provide a drain function for
a selected time period before being reabsorbed by the body. Also,
the tube portion of the drain can be attached with a low force
adhesive or otherwise treated to be detachable using minimally
invasive methods. For embodiment employing a needle device, the
needle can be fabricated from 304V or other stainless steel as well
as super elastic materials such as NITINOL. It can also be
fabricated from various flexible polymers known in the art. The
needle and the other embodiments of the drain device can also
include various fittings such as a Touhy Borst fitting or valve for
connection to vacuum sources, pumps, pressure lines, and the
like.
[0102] In other approaches for draining blood from the vessel space
US, the balloon support member or other mechanical support member
can be shaped so as to not form a seal with the wall of the
aneurysm or adjoining artery when they are in an expanded state.
This allows blood to flow around the balloon/expansion device
desirably both at the proximal and distal end of the device. Such
embodiment also allows any blood located in vessel space US to flow
out or be squeegeed out from the aneurysm site as the filling
structure is expanded. Referring now to FIGS. 11A-11B, in specific
embodiments, the balloon 16 can comprise a lobe shaped balloon 161
have a multi-lobed cross sectional profile 161p which allows blood
to flow in the valleys 17V between the lobes 17 while peaks 17P of
the lobes 17 provide support to maintain the tubular shape of the
inner lumen 121 of filling member 12. Valley 17p can also be
configured to allow for the passage of a pressure sensing member 63
from a proximal to a distal end of the balloon. Balloon 161 can
have a selectable number of lobes 17, for example, between three
and five lobes depending upon the size of lumen 121 and the desired
amount of blood flow. In one embodiment the balloon can have a
three lobe profile 161p.
[0103] Referring now to FIGS. 12A-13B, other embodiments a balloon
that allows for blood flow through lumen 121, can comprise a
multi-balloon member 16mb made of two or more individual balloons
16 that are joined together or share a common wall, for example, a
three balloon member. These embodiments are configured to allow for
blood flow in the spaces 16s between the balloons when they are
inflated. Such embodiments can have a multi-spherical
cross-sectional profile 16sp. In a preferred embodiment shown in
FIGS. 12A and 12B, a multi-balloon support member 16mb can comprise
three balloons and thus have a tri-spherical cross sectional
profile 16sp. Use of such of an embodiment of a multi-balloon
support member is illustrated in FIGS. 13A-B which show how blood
can flow through the balloon space 16s and thus allow for both flow
through lumen 121 and drainage of blood from space US when the
balloon are inflated and the filling structure is being filled.
[0104] Referring now to FIGS. 14A-C, another embodiment for a
support member that allows blood through lumen 121 when in the
expanded state can include and expandable shape memory stent 16t
comprising a plurality of flexible splines 19 that form a
scaffolding structure 19s that is able to support lumen 12. The
stent can have a non-deployed state shown in FIG. 14A and an
expanded or deployed state shown in FIG. 14B. The stent can be
fabricated from various super elastic shape memory materials known
in the art such as nickel titanium alloys. In a preferred
embodiment, the stent is fabricated from NITINOL. The stent may
also be coated with various non-thrombogenic coatings, including
eluting coatings known in the art. Stent 16t can be put into the
expanded state by the application of either tension or compression
from delivery catheter 14 or guidewire GW or another pull wire not
shown. FIG. 14C illustrates how the scaffolding supports lumen 121
and how blood is able to readily flow through the stent when it is
put into the expanded state.
[0105] Another embodiment of an expandable mechanical support
structure that allows blood flow is shown FIGS. 15A-15C. This
structure is similar to stent 16 but comprises a basket like
structure 16b that also is fabricated from a plurality of splines
19 that have an outwardly curved spring memory shape which they
assume when they are released into the expanded state. The splines
desirably have sufficient spring memory to hold lumen 121 open.
Similar to stent 16t, the basket structure can be put into the
expanded state through the application of tension or compression
from guidewire GW or catheter 14. The splines can also be held in
the contracted state through a series of ring constraints 19r.
Alternatively the splines need not have an outwardly bowed spring
memory but rather can be held in that position through the
application of tension or compression from guidewire GW or catheter
14.
[0106] Yet another embodiment of an expandable mechanical support
structure that allows blood flow is shown by FIGS. 16A-B. This
embodiment comprises a mechanically expandable support structure 16
having a plurality of flexible spring arms members 21 that can be
pulled into an expanded state by a series of connected pull wires
21w. Pull wires 21w can be positioned in guidewire lumen 18 or
another lumen of catheter 14 and can be coupled to a common
actuator (not shown) to pull all of them an equal amount at the
same time. The actuator can have a locking feature to lock the arm
members in the expanded state and also can be indexed for a
selectable amount of outward radial expansion of the arm members so
as to define a diameter 12D between opposing arm members for
supporting lumen 121. There can also be several groups of arms 21g
members spaced longitudinally along catheter 14 to provide several
rings of radial support 21 for supporting lumen 121. Also, there
can be partially radially constrained/supported by a ring structure
21rs positioned on catheter 14. Desirably, arm members 21 have
sufficient spring memory in the straightened state such that they
will resume this shape when released by pull wires 21w. Arm members
21 can be fabricated from various spring and shape memory metals
known in the art as well as various flexible polymers known in the
art. All or a portion of the arm members can be coated with a
biomaterial coating including non-thrombogenic coating. Desirable
the arm member tips 21t are configured to be atraumatic and can be
either coated, smoothed or caped. They can also be pre-shaped to be
either straight or curved and can have a number or radio-opaque or
echogenic markers positioned along their lengths.
[0107] In other embodiments, filling member 12 can be configured so
as not to need support during filling/inflation and also during the
perfusion of blood through lumen 121 during filling. Referring now
to FIGS. 17A-18B, one embodiment of such a filling member comprise
a coiled structure 12c that has an open central lumen 121 for blood
flow which does not need support during filling. Specifically the
coiled structure has sufficient radial strength that it does not
need radial support similar to maintain its shape when inflated,
similar to the mechanics of an inner tube. In one embodiment, the
coiled structure can comprise a series of individual inflatable
coils 12ic having an inner tube like structure that are joined and
fluidically coupled to one another to allow simultaneous
filling/inflation as is shown FIG. 17B.
[0108] In another embodiment shown in FIG. 18, the coiled structure
12c can comprise a continuously coiled structure 12cc that has a
helical shape 12h when unconstrained. It can then be wrapped or
packed around catheter 14 to assume a substantially cylindrical
coiled shape when deployed in vivo. This structure can also be
deployed from catheter 14 into an aneurysm site in an extruded like
manner using an overtube or guiding catheter. In another embodiment
shown in FIG. 19, structure 12 can have a "figure eight shape" 12fe
which can be configured for treating aneurysm at or near a vessel
bifurcation. Various embodiments of coiled structure 12c can be
fabricated from various biocompatible elastomers known in the art
including silicone and polyurethane and co-polymers thereof. They
can also be internally supported by braids, struts or other support
element to help maintain the patency of their central lumen.
[0109] Referring now to FIGS. 20A-20C, a method of using a coiled
filling structure 12c is illustrated. The structure can be position
in the desired site AS, using delivery catheter 14. Then coiled
structure 12c is filled/inflated with filling medium 23, without
the need for a support structure 16. However, one can be used if so
desired by the physician. The structure can be filled/inflated in
such a manner as to squeeze out blood from space US in a piston
like manner. That is, as each individual coils of the structure
becomes inflated it push blood from space US down the vessel in the
direction of inflation DI (e.g., proximal in the embodiment shown)
until all of the coils are inflated and all of the blood is forced
out from space US. Each individual coil 12c acts as fluidic seal
12fs which prevents blood from flowing backward against the
direction of inflation DI, thus forces the remaining blood in space
US to travel in the path of least fluidic resistance which is in
the direction of inflation. In use, such embodiments minimize the
likelihood of blood becoming trapped in space US and also excessive
pressure from being exerted against the aneurysm wall thus
minimizing the risk of dissection. Similar to other method
embodiments discussed herein, pressure monitoring can be done
throughout the filling and deployment process to control filling,
determine endpoint and further reduce the risk of
over-pressurization.
[0110] FIGS. 21A-C illustrate a variation of the method describe
above adapted for used with an aneurysm near a vessel bifurcation.
In these embodiments a first and second coiled filling structure
112c and 212c are used. Typically each structure will be positioned
and then filled sequentially as is shown in FIGS. 21B-C though the
physician can elect to do simultaneous or otherwise concurrent
fillings. In either case, pressure monitoring can be done
throughout the procedure as described above to both control the
filling process and determine endpoint.
[0111] Referring now to FIGS. 22A-22C, in some embodiments, the
balloon support member 16 can have a dog bone 16db or like shape
(e.g., a cassini oval) such that the proximal and distal end
portions 16p and 16d of the balloon have an outwardly flared shape
16f or otherwise has a larger diameter than the balloon central
portion 16c. One or both of the end portions 16p and 16d of the
inflated balloon can extend at least partially out of the filling
structure 12 into the native vessel lumen LN. This configuration
serves to shape the lumen 121 of the hardened filling structure
such that the proximal and distal ends of the formed lumen 121p and
121d have an outwardly flared shape 12f (relative to the central
portion 121c) which roughly corresponds to flared shape 16f. This
flared shape 12f serves to provide a smooth transition 12t in
diameter from the native vessel lumen NL to the formed lumen 121 of
structure 12 and in particular, minimizes the surface of the area
of the formed lumen that is normal to the direction of blood flow
BD through the artery. This later configuration serves to minimize
an amount of sheer stress on the formed and adjacent native lumens
as well as reduce an amount of retrograde flow and turbulence in
vessel regions within and adjacent the prosthesis. These fluid
dynamic factors in turn serve to reduce the likelihood of the
formation of stenosis in the region of the prosthetic.
[0112] Referring now to FIG. 23, in other embodiments, perfusion
during inflation of the balloon support member can also be achieved
by the use of a perfusion lumen 141 with proximal and distal
apertures 14ap and 14ad for the inflow and outflow of blood. The
proximal and distal apertures 14ap and 14ad are desirably
positioned on the delivery catheter so as to allow blood to enter
the proximal apertures, flow through the delivery catheter lumen
and exist the distal apertures and/or distal end of the lumen 141e
when the balloon support 16 is inflated before, during or after
filling of filling structure 12. Perfusion can be enhanced through
the use of pressure monitoring to position the inflow and outflow
apertures in areas with greatest blood flow and/or pressure
gradient.
CONCLUSIONS
[0113] The foregoing description of various embodiments of the
invention has been presented for purposes of illustration and
description. It is not intended to limit the invention to the
precise forms disclosed. Many modifications, variations, and
refinements will be apparent to practitioners skilled in the art.
For example, embodiments of the aneurysm repair system, and
prostheses can be adapted to be utilized in the thoracic region of
the aorta or other vasculatures of the body including, without
limitation, the cerebral vasculature and the femoral and popliteal
vasculatures. Also, embodiments of dual filling structure system
can be adapted to treat aneurysms at or near any bifurcation in the
arterial vasculature.
[0114] Elements, characteristics, or acts from one embodiment can
be readily recombined or substituted with one or more elements,
characteristics or acts from other embodiments to form numerous
additional embodiments within the scope of the invention. Moreover,
elements that are shown or described as being combined with other
elements, can, in various embodiments, exist as standalone
elements. Hence, the scope of the present invention is not limited
to the specifics of the described embodiments, but is instead
limited solely by the appended claims.
* * * * *