U.S. patent application number 12/429474 was filed with the patent office on 2010-02-11 for stent graft delivery system.
This patent application is currently assigned to Nellix, Inc.. Invention is credited to Michael A. Evans, Matthew R. Hellewell, Steven L. Herbowy, Anant Kumar, Gil Laroya, K.T. Venkateswara Rao.
Application Number | 20100036360 12/429474 |
Document ID | / |
Family ID | 41217164 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100036360 |
Kind Code |
A1 |
Herbowy; Steven L. ; et
al. |
February 11, 2010 |
STENT GRAFT DELIVERY SYSTEM
Abstract
A system for treating an aneurysm comprises an elongate flexible
shaft and an expandable member. An expandable scaffold is disposed
over the expandable member and may be expanded from a collapsed
configuration to an expanded configuration. A double-walled filling
structure is disposed over the scaffold and has an outer wall and
an inner wall. The filling structure is adapted to be filled with a
hardenable fluid filing medium so that the outer wall conforms to
an inside surface of the aneurysm and the inner wall forms a
substantially tubular lumen to provide a path for blood flow. In
the expanded configuration the scaffold engages the inner wall of
the filling structure. A tether is releasably coupled with the
filling structure and the flexible shaft thereby constraining axial
movement of the structures relative to each other.
Inventors: |
Herbowy; Steven L.; (Palo
Alto, CA) ; Evans; Michael A.; (Palo Alto, CA)
; Kumar; Anant; (San Jose, CA) ; Rao; K.T.
Venkateswara; (San Jose, CA) ; Hellewell; Matthew
R.; (Menlo Park, CA) ; Laroya; Gil; (Santa
Clara, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Nellix, Inc.
Palo Alto
CA
|
Family ID: |
41217164 |
Appl. No.: |
12/429474 |
Filed: |
April 24, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61048038 |
Apr 25, 2008 |
|
|
|
Current U.S.
Class: |
604/500 ;
600/300; 604/96.01; 606/194 |
Current CPC
Class: |
A61F 2002/30604
20130101; A61B 17/12136 20130101; A61F 2210/0085 20130101; A61F
2250/006 20130101; A61F 2002/067 20130101; A61B 17/12195 20130101;
A61F 2/90 20130101; A61M 25/10182 20131105; A61M 25/10187 20131105;
A61M 25/10188 20131105; A61F 2002/077 20130101; A61B 17/12118
20130101; A61F 2230/0034 20130101; A61F 2/07 20130101; A61F 2/954
20130101; A61M 25/1018 20130101; A61B 17/12186 20130101; A61F
2002/30583 20130101; A61F 2250/0003 20130101; A61M 25/007 20130101;
A61F 2002/9511 20130101 |
Class at
Publication: |
604/500 ;
606/194; 604/96.01; 600/300 |
International
Class: |
A61M 31/00 20060101
A61M031/00; A61M 29/00 20060101 A61M029/00; A61B 5/00 20060101
A61B005/00 |
Claims
1. A system for treating an aneurysm in a blood vessel, the system
comprising: an elongate flexible shaft having a proximal region and
a distal region; a first double-walled filling structure disposed
over the distal region of the shaft, the filling structure having
an outer wall and an inner wall, wherein the filling structure is
adapted to be filled with a hardenable fluid filing medium so that
the outer wall conforms to an inside surface of the aneurysm and
the inner wall forms a first substantially tubular lumen to provide
a path for blood flow; and at least a first expandable scaffold
disposed adjacent the filling structure, the first scaffold
radially expandable within at least a portion of the tubular lumen
of the filling structure, wherein the filling structure is separate
from the first scaffold and axially separated therefrom.
2. The system according to claim 1, wherein the first scaffold is
proximal to the filling structure.
3. The system according to claim 1, wherein the first scaffold is
distal to the filling structure.
4. The system according to claim 1, wherein a spacing exists
between one end of the first scaffold and one end of the filling
structure.
5. The system according to claim 1, wherein the first scaffold is
slidably received by the filling structure such that the first
scaffold and the filling structure are concentric with one
another.
6. The system according to claim 1, further comprising a sheath
disposed at least partially over the filling structure.
7. The system according to claim 1, further comprising a sheath
disposed at least partially over the scaffold.
8. The system according to claim 1, further comprising a tapered
sheath disposed at least partially over the flexible shaft.
9. The system according to claim 8, wherein the tapered sheath
comprises axially oriented slits near a distal end thereof.
10. The system according to claim 1, further comprising a pusher
tube disposed at least partially over the flexible shaft and
slidably engageable with the first double-walled filling
structure.
11. The system according to claim 1, further comprising a first
tether coupled with the filling structure, the tether adapted to
guide movement of the first double-walled filling structure
relative to the first scaffold axially along the shaft.
12. The system according to claim 11, wherein the first tether
extends between the proximal and distal regions of the flexible
shaft.
13. The system according to claim 11, wherein the filling structure
is slidably engaged with the first tether.
14. The system according to claim 11, further comprising a second
tether coupled with the filling structure.
15. The system according to claim 14, wherein the second tether
extends between the proximal and distal regions of the flexible
shaft.
16. The system according to claim 11, wherein the filling structure
comprises one or more eyelets.
17. The system according to claim 11, further comprising a nosecone
coupled with the distal region of the flexible shaft, wherein the
tether is coupled with the nosecone.
18. The system according to claim 11, wherein a portion of the
tether extends outside of a patient's body.
19. The system according to claim 11, wherein the tether is
releasably coupled with the filling structure.
20. The system according to claim 1, wherein the filling structure
comprises a receptacle coupled with a wall of the filling
structure, the receptacle adapted to slidably receive a tube.
21. The system according to claim 1, further comprising a pressure
monitor, the pressure monitor coupled with the filling structure so
as to permit pressure monitoring of the filling structure as the
filling structure is filled with the hardenable fluid filling
medium.
22. The system according to claim 21, wherein the pressure monitor
is fluidly coupled with the filling structure.
23. The system according to claim 21, wherein the pressure monitor
comprises a pressure gage.
24. The system according to claim 21, wherein the pressure monitor
comprises a digital display or waveform monitor.
25. The system according to claim 1, further comprising an
inflation device fluidly coupled with the filling structure.
26. The system according to claim 25, wherein the inflation device
comprises a syringe.
27. The system according to claim 1, wherein the filling structure
comprises a relief valve.
28. The system according to claim 27, wherein the filling structure
comprises a reservoir fluidly coupled with the relief valve
29. The system according to claim 28, wherein the reservoir is
adapted to receive the hardenable fluid filling medium from the
relief valve at a predetermined pressure.
30. The system according to claim 29, wherein the reservoir is
radiopaque when the reservoir is at least partially filled with the
hardenable fluid filling medium.
31. The system according to claim 27, wherein the relief valve is
fluidly isolated from the first filling structure.
32. The system according to claim 1, wherein the filling structure
comprises a visual indicator fluidly coupled therewith and having
first and second positions, wherein the indicator moves from the
first position to the second position when a predetermined pressure
is applied to the visual indicator.
33. The system according to claim 32, wherein the indicator is
visible under fluoroscopy.
34. The system according to claim 1, further comprising a
collapsible member fluidly coupled with a pressure gage, the
expandable member positioned between the outer wall of the filling
structure and the inside surface of the aneurysm, the pressure gage
adapted to indicate pressure of the filling structure as it is
filled.
35. The system according to claim 34, wherein the collapsible
member comprises a balloon.
36. The system according to claim 1, further comprising a
collapsible member positioned between the outer wall of the filling
structure and the inside wall of the aneurysm, the collapsible
member fluidly coupled with a compression mechanism having a first
position and a second position, the compression mechanism adapted
to provide a predetermined force opposing the force exerted by the
collapsible member as the filling structure is filled, the
compression mechanism moving from the first position to the second
position when the force exerted by the collapsible member exceeds
the predetermined force.
37. The system according to claim 36, wherein the compression
mechanism comprises a spring.
38. The system according to claim 36, wherein the collapsible
member comprises a balloon.
39. The system according to claim 1, further comprising a locking
mechanism, wherein the locking mechanism prevents fluid from
filling the filling structure when the filling structure is filled
to a predetermined pressure.
40. The system according to claim 1, wherein the filling structure
comprises a compliant compartment adapted to deform as the outer
wall of the filling structure conforms to the inside surface of the
aneurysm.
41. The system according to claim 40, wherein the compartment is
fluidly coupled with a pressure indicator.
42. The system according to claim 35, wherein the balloon comprises
a substantially flat section.
43. The system according to claim 1, wherein the first scaffold
comprises crushable regions and remainder regions, the crushable
regions adapted to collapse when the filling structure is
pressurized to a predetermined value while the remainder regions
remain fully expanded.
44. The system according to claim 1, further comprising an
expandable member expandable from a contracted configuration to an
expanded configuration and coupled with the shaft near the distal
region.
45. The system according to claim 44, wherein the expandable member
comprises a balloon.
46. The system according to claim 45, wherein the balloon comprises
a pre-shaped, curved or tapered region.
47. The system according to claim 44, wherein the expandable member
is coupled to a pressure monitoring device.
48. The system according to claim 1, wherein the scaffold is
balloon expandable.
49. The system according to claim 1, wherein the scaffold comprises
a metal.
50. The system according to claim 1, wherein the scaffold or the
filling structure carries a therapeutic agent adapted to being
released therefrom in a controlled manner.
51. The system according to claim 1, wherein the filling structure
comprises a polymer.
52. The system according to claim 1, further comprising a
releasable coupling mechanism coupled with the first filling
structure and the shaft, wherein the coupling mechanism is adapted
to reduce relative axial movement along the shaft of the first
filling structure relative to the first scaffold.
53. The system according to claim 52, wherein the releasable
coupling mechanism comprises a tether releasably coupled with the
shaft and the first filling structure.
54. The system according to claim 1, wherein the first filling
structure comprises a filling tube fluidly coupled therewith and
adapted to fill the filling structure with the filling medium.
55. The system according to claim 54, wherein the filling tube
comprises an inner tube slidably disposed in the filling tube, both
the inner tube and the filling tube fluidly coupled with the
filling structure.
56. The system according to claim 1, further comprising: a second
double-walled filling structure having an outer wall and an inner
wall, wherein said second double-walled filling structure is
adapted to be placed adjacent the first filling structure in the
aneurysm and to be filled with a hardenable fluid filling medium so
that the outer wall conforms to the inside surface of the aneurysm
and to the first filling structure and forms a second generally
tubular lumen to provide a path for blood flow; and at least a
second scaffold separate from the first scaffold and the filling
structures which can be expanded within at least a portion of the
second tubular lumen of the second filling structure, wherein the
second scaffold is axially separated from the second filling
structure.
57. The system according to claim 56, wherein the second scaffold
is balloon expandable.
58. The system according to claim 56, wherein the second scaffold
comprises a metal.
59. The system according to claim 56, wherein the second filling
structure comprises a polymer.
60. The system according to claim 1, further comprising a flowable
polymer filling material curable in situ.
61. A method for treating an aneurysm, said method comprising:
providing an elongate flexible shaft having a proximal end and a
distal end, the flexible shaft carrying a first double-walled
filling structure and a first scaffold adjacent the distal end;
advancing the elongate shaft in a patient's vasculature such that
the first double-walled filling structure traverses the aneurysm;
axially moving the first scaffold relative to the first filling
structure such that at least a portion of the first scaffold is
disposed within the first double-walled filling structure; radially
expanding the first scaffold from a contracted configuration to an
expanded configuration; and filling the first filling structure
with a fluid filling medium so that an outer wall of the first
filling structure conforms to an inside surface of the aneurysm and
an inner wall of the first filling structure forms a first
substantially tubular lumen to provide a first blood flow path
across the aneurysm, and wherein the at least a portion of the
first double-walled filling structure is disposed in the first
substantially tubular lumen.
62. The method of claim 61, wherein axially moving the first
scaffold comprises moving the first scaffold distally into the
first lumen.
63. The method of claim 61, wherein axially moving the first
scaffold comprises proximally retracting the first filling
structure over the first scaffold.
64. The method of claim 61, wherein axially moving the first
scaffold comprises proximally retracting the first scaffold into
the first lumen.
65. The method of claim 61, wherein axially moving the first
scaffold comprises moving the first filling structure distally over
the first scaffold.
66. The method of claim 61, wherein axially moving the first
scaffold comprises guiding the first filling structure over a
tether line.
67. The method of claim 61, wherein axially moving the first
scaffold comprises pulling the first filling structure with a
tether line.
68. The method of claim 61, further comprising retracting a sheath
from the first filling structure so that the first filling
structure is unconstrained from expansion.
69. The method of claim 68, wherein retracting the sheath comprises
splitting the sheath.
70. The method of claim 61, further comprising retracting a sheath
from the first scaffolding so that the first scaffolding is
unconstrained from expansion.
71. The method of claim 61, further comprising hardening the fluid
filling medium in the first filling structure.
72. The method of claim 61, further comprising engaging a pusher
tube with the first filling structure thereby preventing movement
thereof.
73. The method of claim 61, further comprising monitoring a
pressure.
74. The method of claim 73, wherein the pressure is exerted by the
filling medium within the first filling structure.
75. The method of claim 61, wherein the step of filling the filling
structure comprises controlling pressure or volume of the fluid
filling medium.
76. The method of claim 73, wherein the monitored pressure is
within a space between an external wall of the first filling
structure and a wall of the aneurysm.
77. The method of claim 76, wherein monitoring the pressure
comprises placing a catheter in the space.
78. The method of claim 77, wherein the catheter comprises a fluid
filled balloon.
79. The method of claim 76, wherein monitoring the pressure
comprises placing a pressure transducer in the space.
80. The method of claim 73, wherein filling the filling structure
comprises actuating an injection device and wherein the pressure is
monitored at a position adjacent the injection device.
81. The method of claim 73, further comprising relieving pressure
in the filling structure with a relief valve when the pressure
exceeds a predetermined value.
82. The method of claim 81, further comprising filling a reservoir
fluidly coupled with the relief valve.
83. The method of claim 82, further comprising observing the
reservoir.
84. The method of claim 81, further comprising isolating the relief
valve from the first filling structure so that the relief valve is
fluidly isolated therefrom.
85. The method of claim 73, further comprising observing a visual
indicator coupled with the first filling structure, the indicator
having first and second positions, wherein the indicator moves from
the first position to the second position when a predetermined
pressure is applied to the visual indicator.
86. The method of claim 73, further comprising positioning a
collapsible member between the outer wall of the filling structure
and the inside wall of the aneurysm and further comprising
observing a compression mechanism having a first position and a
second position, the compression mechanism adapted to provide a
predetermined force opposing the force exerted by the collapsible
member as the filling structure is filled, the compression
mechanism moving from the first position to the second position
when the force exerted by the collapsible member exceeds the
predetermined force.
87. The method of claim 86, wherein the compression mechanism
comprises a spring.
88. The method of claim 86, wherein the collapsible member
comprises a balloon.
89. The method of claim 73, further comprising stopping the filling
of the filling structure when the monitored pressure reaches a
predetermined pressure.
90. The method of claim 89, wherein stopping the filling comprises
mechanically locking a filling device so that fluid may not be
delivered therefrom.
91. The method of claim 73, wherein monitoring comprises observing
the first scaffold, the first scaffold comprising crushable regions
and remainder regions, the crushable regions adapted to collapse
when the filling structure is pressurized to a predetermined value
while the remainder regions remain fully expanded.
92. The method of claim 61, wherein the step of radially expanding
the first scaffold comprises inflating a balloon disposed near the
distal end of the elongate shaft.
93. The method of claim 92, wherein the balloon comprises a
pre-shaped, curved or tapered region.
94. The method of claim 61, further comprising releasing a
releasable coupling mechanism that couples the filling structure
with the shaft to allow axial movement of the filling structure
relative to the first scaffold and to allow release of the filling
structure from the shaft.
95. The method of claim 94, wherein releasing the coupling
mechanism comprises releasing a knot in a tether joining the
filling structure with the shaft.
96. The method of claim 61, wherein a filling tube is fluidly
coupled with the filling structure, and the step of filling the
filling structure comprises passing the fluid filling medium
through the filling tube to the filling structure.
97. The method of claim 96, wherein the filling tube comprises an
inner tube slidably disposed therein and in fluid communication
with the filling structure, the method further comprising removing
the inner tube and passing additional fluid filling medium through
the filling tube after the inner tube has been removed.
98. The method of claim 61, further comprising: providing a second
elongate flexible shaft having a proximal and distal end, the
second shaft carrying a second double-walled filling structure and
a second scaffold adjacent the distal end; advancing the second
elongate shaft in the patient's vasculature such that the second
double-walled filling structure traverses the aneurysm; axially
moving the second scaffold relative to the second filling structure
such that at least a portion of the second scaffold is disposed
within the second double-walled filling structure; filling the
second filling structure with a fluid filling medium so that an
outer wall of the second filling structure forms a second
substantially tubular lumen to provide a second blood flow path
across the aneurysm, and wherein at least a portion of the second
scaffold is disposed in the second substantially tubular lumen; and
radially expanding the second scaffold from a contracted
configuration to an expanded configuration.
99. The method of claim 98, wherein axially moving the second
scaffold comprises moving the second scaffold distally into the
second lumen.
100. The method of claim 98, wherein axially moving the second
scaffold comprises proximally retracting the second filling
structure over the second scaffold.
101. The method of claim 98, wherein axially moving the second
scaffold comprises proximally retracting the second scaffold into
the second lumen.
102. The method of claim 98, wherein axially moving the second
scaffold comprises moving the second filling structure distally
over the second scaffold.
103. The method of claim 98, further comprising retracting a sheath
from the second filling structure so that the second filling
structure is unconstrained from expansion.
104. The method of claim 103, wherein retracting the sheath
comprises splitting the sheath.
105. The method of claim 98, further comprising retracting a sheath
from the second scaffolding so that the second scaffolding is
unconstrained from expansion.
106. The method of claim 98, further comprising hardening the fluid
filling medium in the second filling structure.
107. The method of claim 98, further comprising monitoring a second
pressure, the second pressure being exerted by the filling medium
within the second filling structure.
108. The method of claim 98, wherein the step of filling the second
filling structure comprises controlling pressure or volume of the
fluid filling medium.
109. The method of claim 98, further comprising inflating a balloon
on either the first or second elongate shaft so as to compress the
first and second filling structures against one another and against
the aneurysm wall.
110. The method of claim 109, wherein filling medium is discharged
from either the first or second filling structure.
111. The method of claim 98, further comprising filling either the
first or the second filling structure until it engages the other
filling structure resulting in filling medium being discharged from
either the first or second filling structure.
112. The method of claim 98, wherein the step of radially expanding
the second scaffold comprises inflating a balloon disposed near the
distal end of the second shaft.
113. The method of claim 112, wherein the balloon on the second
shaft comprises a pre-shaped, curved or tapered region.
114. A system for treating an aneurysm in a blood vessel, said
system comprising: an elongate flexible shaft having a proximal
region and a distal region; an expandable member disposed adjacent
the distal region; a first expandable scaffold disposed over the
expandable member, the first scaffold radially expandable from a
collapsed configuration to an expanded configuration; a first
double-walled filling structure disposed over the first scaffold,
the filling structure having an outer wall and an inner wall,
wherein the filling structure is adapted to be filled with a
hardenable fluid filing medium so that the outer wall conforms to
an inside surface of the aneurysm and the inner wall forms a first
substantially tubular lumen to provide a path for blood flow,
wherein the first scaffold in the expanded configuration engages
the inner wall of the filling structure; and a first releasable
coupling mechanism releasably coupling the filling structure with
the flexible shaft, wherein the coupling mechanism constrains axial
movement of the filling structure relative to the flexible
shaft.
115. The system of claim 114, wherein the releasable coupling
mechanism comprises a first tether.
116. The system of claim 115, wherein the tether comprises a
suture.
117. The system of claim 115, further comprising a lockwire
disposed alongside the flexible shaft, wherein a distal end of the
lockwire is releasably coupled with the flexible shaft.
118. The system of claim 117, wherein the flexible shaft comprises
a tapered nosecone having an aperture therein, the nosecone coupled
with the distal region of the flexible shaft, and wherein the
distal end of the lockwire is releasably coupled with and slidably
received in the nosecone aperture.
119. The system of claim 117, wherein the first tether is
releasably coupled to the lockwire.
120. The system of claim 119, wherein the filling structure
comprises a first tether loop fixedly attached thereto, and wherein
the first tether passes through the tether loop.
121. The system of claim 120, wherein the first tether loop is
disposed on a distal end of the filling structure.
122. The system of claim 119, wherein the first tether is
releasably coupled to the lockwire with a knot.
123. The system of claim 122, wherein the knot comprises a
constrictor knot.
124. The system of claim 115, wherein one end of the first tether
is fixedly attached with the flexible shaft.
125. The system of claim 117, further comprising a second
releasable coupling mechanism releasably coupled with the filling
structure and the flexible shaft, the second coupling mechanism
disposed on an opposite end of the filling structure as the first
coupling mechanism, and wherein the second coupling mechanism
constrains axial movement of the filling structure relative to the
flexible shaft.
126. The system of claim 125, wherein the second coupling mechanism
comprises a second tether.
127. The system of claim 126, wherein the second tether comprises a
suture.
128. The system of claim 126, wherein the second tether is
releasably coupled to the lockwire.
129. The system of claim 128, wherein the second tether is looped
around the lockwire.
130. The system of claim 126, wherein the filling structure
comprises a second tether loop fixedly attached thereto and
disposed on an opposite end as the first tether loop, and wherein
the second tether passes through the second tether loop.
131. The system of claim 126, wherein the second tether is coupled
to the flexible shaft.
132. The system of claim 131, wherein the second tether is
releasably coupled to the flexible shaft with a knot.
133. The system of claim 132, wherein the knot comprises a
constrictor knot.
134. The system of claim 125, wherein the first filling structure
comprises a fill tube fluidly coupled therewith, and wherein the
second coupling mechanism is coupled with the fill tube so as to
prevent release of the fill tube from the filling structure.
135. The system of claim 114, further comprising a second
releasable coupling mechanism releasably coupled with the filling
structure and the flexible shaft, wherein the second mechanism is
disposed on the same end of the filling structure as the first
releasable coupling mechanism, and wherein the second mechanism
constrains axial movement of the filling structure relative to the
flexible shaft.
136. The system of claim 135, wherein the second mechanism
comprises a second tether.
137. The system of claim 136, wherein the second tether comprises a
suture.
138. The system of claim 136, further comprising a second lockwire
disposed alongside the flexible shaft, wherein a distal end of the
second lockwire is releasably coupled with the flexible shaft.
139. The system of claim 138, wherein the flexible shaft comprises
a tapered nosecone having a second aperture therein, the nosecone
coupled with the distal region of the flexible shaft, and wherein
the distal end of the second lockwire is releasably coupled with
and slidably received in the second nosecone aperture.
140. The system of claim 138, wherein the second tether is
releasably coupled to the lockwire.
141. The system of claim 136, wherein the filling structure
comprises a second tether loop fixedly attached thereto, and
wherein the second tether passes through the second tether
loop.
142. The system of claim 141, wherein the second tether loop is
disposed on the same end of the filling structure as the first
tether loop.
143. The system of claim 138, wherein the second tether is
releasably coupled to the lockwire with a knot.
144. The system of claim 143, wherein the knot comprises a
constrictor knot.
145. The system of claim 136, wherein one end of the second tether
is fixedly attached with the flexible shaft.
146. The system of claim 114, further comprising a filling tube
fluidly coupled with the filling structure, the filling tube
adapted to deliver the hardenable filling medium to the filling
structure.
147. The system of claim 146, wherein the filling tube comprises a
plurality of apertures near a distal end thereof, the apertures
adapted to allow the hardenable filling medium to flow therethrough
into the filling structure.
148. The system of claim 146, wherein the filling tube comprises an
inner filling tube and an outer filling tube slidably disposed
thereover, both inner and outer tubes fluidly coupled with the
filling structure.
149. The system of claim 146, further comprising a stylet disposed
in the filling tube.
150. The system of claim 146, further comprising a filling tab
fluidly coupled with the filling structure and fluidly coupled with
the filling tube.
151. The system of claim 150, wherein the filling tab comprises a
scored region adapted to permit separation of the filling tab into
two portions, the first portion remaining coupled with the filling
structure after filling thereof with the hardenable filling medium
and the second portion discrete and independent of the first
portion.
152. The system of claim 114, further comprising an outer sheath
having a lumen, wherein the filling structure, the scaffold and the
expandable member are disposed with the sheath lumen during
delivery of the system to a treatment site.
153. The system of claim 114, wherein the expandable member
comprises an inflatable balloon.
154. The system of claim 153, wherein the balloon comprises a
pre-shaped, curved or tapered region.
155. The system of claim 114, further comprising a pressure
monitor, the pressure monitor coupled with the first filling
structure so as to permit pressure monitoring of the filling
structure as the filling structure is filled with the hardenable
fluid filling medium.
156. The system of claim 114, further comprising: a second elongate
flexible shaft having a proximal region and a distal region; a
second expandable member disposed adjacent the distal region; a
second expandable scaffold disposed over the second expandable
member, the second scaffold radially expandable from a collapsed
configuration to an expanded configuration; a second double-walled
filling structure disposed over the second scaffold, the second
filling structure having an outer wall and an inner wall, wherein
the second filling structure is adapted to be filled with a
hardenable fluid filing medium so that the outer wall conforms to
an inside surface of the aneurysm and to the first double-walled
filling structure, and the inner wall forms a first substantially
tubular lumen to provide a path for blood flow, wherein the second
scaffold in the expanded configuration engages the inner wall of
the filling structure; and a tether releasably coupled with the
second filling structure and the second flexible shaft, wherein the
tether constrains axial movement of the second filling structure
relative to the second flexible shaft.
157. A method for treating an aneurysm in a patient, said method
comprising: providing an elongate flexible shaft having a proximal
end, a distal end, and an expandable member near the distal end,
the flexible shaft carrying a first radially expandable scaffold
over the expandable member and a first double walled filling
structure disposed over the first scaffold; advancing the shaft in
the vasculature of the patient so that the first filling structure
is delivered to the aneurysm; filling the first filling structure
with a first fluid filling medium so that an outer wall of the
first filling structure conforms to an inside surface of the
aneurysm and an inner wall of the first filling structure forms a
first substantially tubular lumen to provide a first blood flow
path across the aneurysm; radially expanding the first scaffold
from a contracted configuration to an expanded configuration,
wherein in the expanded configuration the first scaffold engages
the inner wall of the first filling structure; hardening the fluid
filling medium in the first filling structure; releasing the first
filling structure from the flexible shaft; and retracting the
flexible shaft away from the first filling structure.
158. The method of claim 157, further comprising: pre-filling the
first filling structure with a pre-filling fluid until the outer
wall of the first filling structure conforms to the inside surface
of the aneurysm, thereby unfurling the first filling structure; and
removing the pre-filling fluid from the first filling
structure.
159. The method of claim 158, wherein the pre-filling fluid
comprises saline.
160. The method of claim 158, further comprising: pre-filling the
first filling structure with pre-filling fluid until the outer wall
of the first filling structure conforms to the inside surface of
the aneurysm; measuring the pressure and volume of the pre-filling
fluid used to pre-fill the first filling structure; and removing
the pre-filling fluid from the first filling structure, wherein the
step of filling the first filling structure with the first fluid
filling medium comprises filling the first filling structure with
the first filling medium using substantially the same pressure and
volume as measured.
161. The method of claim 160, wherein the pre-filling fluid
comprises saline.
162. The method of claim 160, wherein the pre-filling fluid
comprises contrast media.
163. The method of claim 158, wherein the step of filling the first
filling structure comprises passing the first fluid medium through
a filling tube fluidly coupled with the first filling
structure.
164. The method of claim 157, wherein the first filling structure
comprises a filling tube fluidly coupled therewith, and the step of
filling the first filling structure comprises passing the filling
medium through the filling tube.
165. The method of claim 164, wherein the filling tube comprises an
inner tube slidably disposed therein and fluidly coupled with the
first filling structure, the method further comprising removing the
inner tube from the filling tube and supplying additional filling
medium to the filling structure by passing the additional filling
medium through the filling tube after the inner tube has been
removed therefrom.
166. The method of claim 157, wherein the step of radially
expanding the scaffold comprises inflating a balloon disposed on
the flexible shaft.
167. The method of claim 166, wherein the balloon comprises a
pre-shaped, curved or tapered region.
168. The method of claim 157, wherein the step of hardening the
first fluid filling medium in the first filling structure comprises
polymerizing the first fluid filling medium in situ.
169. The method of claim 168, wherein the first fluid filling
medium comprises polyethylene glycol.
170. The method of claim 157, wherein a releasable coupling
mechanism couples the first filling structure with the flexible
shaft and the step of releasing the first filling structure from
the flexible shaft comprises releasing the coupling mechanism from
the first filling structure.
171. The method of claim 170, wherein the coupling mechanism
comprises a tether and the step of releasing the coupling mechanism
comprises detaching the tether from the first filling
structure.
172. The method of claim 171, wherein one end of the tether is
releasably coupled with a lockwire and the step of de-coupling the
tether comprises retracting the lockwire thereby detaching the
tether from the lockwire.
173. The method of claim 171, wherein detaching the tether
comprises releasing the tether from a tether loop on the first
filling structure.
174. The method of claim 171, wherein a second releasable coupling
mechanism couples the first filling structure with the flexible
shaft and the step of releasing the first filling structure from
the flexible shaft comprises de-coupling the second coupling
mechanism from the first filling structure.
175. The method of claim 171, wherein the first filling structure
comprises a fill tube fluidly coupled therewith, and wherein a
second releasable coupling mechanism is coupled with the fill tube
such that the step of releasing the first filling structure from
the flexible shaft comprises de-coupling the second coupling
mechanism from the fill tube to allow separation of the fill tube
from the filling structure.
176. The method of claim 157, further comprising the step of
retracting a sheath away from the first filling structure and the
first scaffold to allow expansion thereof.
177. The method of claim 157, further comprising the step of
monitoring a pressure during filling of the first filling
structure.
178. The method of claim 177, wherein the pressure comprises a
pressure of the filling medium in the first filling structure.
179. The method of claim 177, wherein the pressure comprises a
pressure in a space between the outer wall of the first filling
structure and a wall of the aneurysm.
180. The method of claim 157, further comprising releasing a
filling tube from the first filling structure.
181. The method of claim 180, wherein the step of releasing the
filling tube comprises severing a filling tab coupled with the
first filling structure.
182. The method of claim 157, further comprising: providing a
second elongate flexible shaft having a proximal end, a distal end,
and a second expandable member near the distal end, the second
flexible shaft carrying a second radially expandable scaffold over
the second expandable member and a second double walled filling
structure disposed over the second scaffold; advancing the second
shaft in the vasculature of the patient so that the second filling
structure is delivered to the aneurysm; filling the second filling
structure with a second fluid filling medium so that an outer wall
of the second filling structure conforms to an inside surface of
the aneurysm and to the first double-walled filling structure, and
an inner wall of the second filling structure forms a second
substantially tubular lumen to provide a second blood flow path
across the aneurysm; radially expanding the second scaffold from a
contracted configuration to an expanded configuration, wherein in
the expanded configuration the second scaffold engages the inner
wall of the second filling structure; hardening the second fluid
filling medium in the second filling structure; releasing the
second filling structure from the second flexible shaft; and
retracting the second shaft away from the second filling structure.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a non-provisional of, and claims
the benefit of U.S. Provisional Application No. 61/048,038
(Attorney Docket No. 025925-002600US), filed on Apr. 25, 2008, the
full disclosure of which is incorporated herein by reference.
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED
RESEARCH AND DEVELOPMENT
[0002] NOT APPLICABLE
REFERENCE TO A "SEQUENCE LISTING," A TABLE, OR A COMPUTER PROGRAM
LISTING APPENDIX SUBMITTED ON A COMPACT DISK.
[0003] NOT APPLICABLE
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The present invention relates generally to medical systems
and methods for treatment. More particularly, the present invention
relates to systems and methods for treating aneurysms.
[0006] 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.
[0007] The present invention is particularly concerned with
aneurysms occurring in the aorta, particularly those referred to as
aortic aneurysms. Abdominal aortic aneurysms (AAA's) are classified
based on their location within the aorta as well as their shape and
complexity. Aneurysms which are found below the renal arteries are
referred to as infrarenal abdominal aortic aneurysms. Suprarenal
abdominal aortic aneurysms occur above the renal arteries, while
thoracic aortic aneurysms (TAA's) occur in the ascending,
transverse, or descending part of the upper aorta.
[0008] Infrarenal aneurysms are the most common, representing about
eighty percent (80%) of all aortic aneurysms. Suprarenal aneurysms
are less common, representing about 20% of the aortic aneurysms.
Thoracic aortic aneurysms are the least common and often the most
difficult to treat.
[0009] The most common form of aneurysm is "fusiform," where the
enlargement extends about the entire aortic circumference. Less
commonly, the aneurysms may be characterized by a bulge on one side
of the blood vessel attached at a narrow neck. Thoracic aortic
aneurysms are often dissecting aneurysms caused by hemorrhagic
separation in the aortic wall, usually within the medial layer. The
most common treatment for each of these types and forms of aneurysm
is open surgical repair. Open surgical repair is quite successful
in patients who are otherwise reasonably healthy and free from
significant co-morbidities. Such open surgical procedures 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.
[0010] Over the past decade, endoluminal grafts have come into
widespread use for the treatment of aortic aneurysm in patients who
cannot undergo open surgical procedures. In general, endoluminal
repairs access the aneurysm "endoluminally" through either or both
iliac arteries in the groin. The grafts, which typically have been
fabric or membrane tubes supported and attached by various stent
structures, are then implanted, typically requiring several pieces
or modules to be assembled in situ. Successful endoluminal
procedures have a much shorter recovery period than open surgical
procedures.
[0011] Present endoluminal aortic aneurysm repairs, however, suffer
from a number of limitations. For example, a significant number of
endoluminal repair patients experience leakage at the proximal
juncture (attachment point closest to the heart) within two years
of the initial repair procedure. While such leaks can often be
fixed by further endoluminal procedures, the need to have such
follow-up treatments significantly increases cost and is certainly
undesirable for the patient. A less common but more serious problem
has been graft migration. In instances where the graft migrates or
slips from its intended position, open surgical repair is required.
This is a particular problem since the patients receiving the
endoluminal grafts are often those who are not considered to be
good surgical candidates.
[0012] Further shortcomings of the present endoluminal graft
systems relate to both deployment and configuration. For example,
many of the commercially available endovascular systems are too
large (above 12 F) for percutaneous introduction. Moreover, current
devices often have an annular support frame that is stiff and
difficult to deliver as well as unsuitable for treating many
geometrically complex aneurysms, particularly infrarenal aneurysms
with little space between the renal arteries and the upper end of
the aneurysm, referred to as short-neck or no-neck aneurysms.
Aneurysms having torturous geometries, are also difficult to
treat.
[0013] For these reasons, it would be desirable to provide improved
methods and systems for the endoluminal and minimally invasive
treatment of aortic aneurysms. In particular, it would be desirable
to provide systems having lower delivery profile and methods which
can be delivered percutaneously and that can track and be deployed
in tortuous vessels. It would also be desirable to provide
prostheses with minimal or no endoleaks, which resist migration,
which are flexible and relatively easy to deploy, and which can
treat many if not all aneurismal configurations, including
short-neck and no-neck aneurysms as well as those with highly
irregular and asymmetric geometries. It would be further desirable
to provide systems and methods which are compatible with current
designs for endoluminal stents and grafts, including single lumen
stents and grafts, bifurcated stents and grafts, parallel stents
and grafts, as well as with double-walled filling structures which
are the subject of the commonly owned, copending applications
described below. It would also be desirable to provide systems and
methods that provide feedback to the operator as to the positioning
and deployment of the endoluminal repair device in the aneurysm.
The systems and methods would preferably be deployable with the
stents and grafts at the time the stents and grafts are initially
placed. Additionally, it would be desirable to provide systems and
methods for repairing previously implanted aortic stents and
grafts, either endoluminally or percutaneously. At least some of
these objectives will be met by the inventions described
hereinbelow.
[0014] 2. Description of the Background Art
[0015] U.S. Patent Publication No. 2006/0025853 describes a
double-walled filling structure for treating aortic and other
aneurysms. Copending, commonly owned U.S. Patent Publication No.
2006/0212112, describes the use of liners and extenders to anchor
and seal such double-walled filling structures within the aorta.
The full disclosures of both these publications are incorporated
herein by reference. PCT Publication No. WO 01/21108 describes
expandable implants attached to a central graft for filling aortic
aneurysms. See also U.S. Pat. Nos. 5,330,528; 5,534,024; 5,843,160;
6,168,592; 6,190,402; 6,312,462; 6,312,463; U.S. Patent
Publications 2002/0045848; 2003/0014075; 2004/0204755;
2005/0004660; and PCT Publication No. WO 02/102282.
BRIEF SUMMARY OF THE INVENTION
[0016] The present invention provides systems and methods for the
treatment of aneurysms, particularly aortic aneurysms including
both abdominal aortic aneurysms (AAA) and thoracic aortic aneurysms
(TAA). The systems may be introduced percutaneously or by surgical
cutdown into a patient and may have an outer diameter ranging
preferably from 10 French to 18 French and more preferably from 12
French to 16 French.
[0017] In a first aspect of the present invention, a system for
treating an aneurysm in a blood vessel comprises an elongate
flexible shaft having a proximal region and a distal region. A
first double-walled filling structure is disposed over the distal
region of the shaft and has an outer wall and an inner wall. The
filling structure may be filled with a hardenable fluid filing
medium so that the outer wall conforms to an inside surface of the
aneurysm and the inner wall forms a first substantially tubular
lumen to provide a path for blood flow. The system also includes a
first expandable scaffold disposed adjacent the filling structure.
The first scaffold is radially expandable within at least a portion
of the tubular lumen of the filling structure and the filling
structure is separate from the first scaffold and axially separated
therefrom.
[0018] In some embodiments, the first scaffold may be proximal to
the filling structure while in other embodiments, the first
scaffold is distal to the filling structure. Sometimes there is a
gap or spacing between one end of the first scaffold and one end of
the filling structure. The first scaffold may be slidably received
by the filling structure so that the first scaffold and the filling
structure are concentric with one another, and the filling
structure provides a covering around the scaffold.
[0019] Sometimes the delivery system may include a sheath that is
disposed at least partially over the filling structure and/or the
scaffold. The sheath may have a tapered tip and may have axially
oriented slits. The system may also include a pusher tube that is
disposed at least partially over the flexible shaft and that
slidably engages with the first double-walled filling structure. A
first tether may be coupled with the filling structure and the
tether may extend between the proximal and distal regions of the
flexible shaft. The tether may be adapted to guide movement of the
first double-walled filling structure relative to the first
scaffold axially along the shaft. The tether may also be used to
pull the filling structure as it is axially moved relative to the
first scaffold, thereby slidably engaging and positioning the
filling structure with the first scaffold. Sometimes the delivery
system may also comprise a second tether that is coupled with the
filling structure and the second tether may extend between the
proximal and distal regions of the flexible shaft. Systems may
include one or more eyelets or suture loops coupled with the first
filling structure and they may be adapted to receive the tethers or
a tube and act as guides or the filling structure may comprise a
receptacle coupled with a wall of the filling structure that can
slidably receive a tube. The system may also include a nosecone
coupled with the distal region of the flexible shaft and sometimes
the tethers are coupled thereto. Portions of the tether may extend
outside of a patient's body. The tether may be releasably coupled
with the filling structure.
[0020] The system may further comprise an inflation device, such as
a syringe, that is fluidly coupled with the filling structure and a
pressure monitor. The pressure monitor may also be coupled with the
filling structure so as to permit pressure monitoring of the
filling structure as the filling structure is filled with the
hardenable fluid filling medium. The pressure monitor may comprise
a pressure gage, a digital display or the like.
[0021] Sometimes the filling structure comprises a relief valve and
an optional reservoir may be fluidly coupled thereto. The relief
valve may be fluidly isolated from the first filling structure and
the reservoir may be adapted to receive the hardenable fluid
filling medium from the relief valve at a predetermined pressure.
The reservoir may be radiopaque when at least partially filled with
the hardenable fluid filling medium. Other embodiments of the
system may have a visual indicator fluidly coupled with the filling
structure. The visual indicator may have first and second positions
wherein the indicator moves from the first position to the second
position when a predetermined pressure is applied to the visual
indicator. This indicator may be visible under fluoroscopy.
[0022] Other embodiments may comprise a collapsible member such as
a balloon that is fluidly coupled with a pressure gage. The
collapsible member may be positioned between the outer wall of the
filling structure and the inside surface of the aneurysm and thus
the pressure gage indicates the pressure of the filling structure
as it is filled. Other embodiments may also include a collapsible
member such as a balloon that is similarly positioned between the
aneurysm wall and the filling structure wall, and that is fluidly
coupled with a compression mechanism, such as a spring, having
first and second positions. The compression mechanism provides a
predetermined force opposing the force exerted by the collapsible
member as the filling structure is filled. The compression
mechanism moves from the first position to the second position when
the force exerted by the collapsible member exceeds the
predetermined value. The collapsible member may be a balloon. Some
systems may also include a locking mechanism which prevents fluid
from filling the filling structure when the filling structure is
filled to a predetermined pressure.
[0023] In some embodiments, the filling structure may comprise a
compliant compartment that deforms as the outer wall of the filling
structure conforms to the inside surface of the aneurysm. The
compartment may have a substantially flat section and may be
fluidly coupled with a pressure indicator.
[0024] Sometimes the first or second scaffold may comprise
crushable regions and remainder regions. The crushable regions
collapse when the filling structure is pressurized to a
predetermined value while the remainder regions remain fully
expanded. In yet other embodiments, the system may further comprise
an expandable member such as a balloon, that expands from a
contracted configuration to an expanded configuration and that is
coupled with the shaft near the distal region. The expandable
member may be fluidly coupled with a pressure monitoring device.
The expandable member may have a pre-shaped, curved or tapered
region.
[0025] The scaffold may be comprised of a metal and may be balloon
expandable. The scaffold or filling structure may also carry a
therapeutic agent that can be released therefrom in a controlled
manner. Some therapeutic agents include anti-thrombogenics like
heparin or agents which promote endothelial and smooth muscle cell
growth, sealing and attachment. The filling structure may comprise
a polymer.
[0026] The system may also comprise a second double-walled filling
structure having an outer wall and an inner wall. The double-walled
filling structure may be placed adjacent the first filling
structure in the aneurysm and may be filled with a hardenable fluid
filling medium so that the outer wall conforms to the inside
surface of the aneurysm and to the first filling structure and
forms a second generally tubular lumen to provide a path for blood
flow. The system may also include a second scaffold separate from
the first scaffold and the filling structures which can be expanded
within at least a portion of the second tubular lumen of the second
filling structure. The second scaffold may be axially separated
from the second filling structure. Both the second scaffold and the
second filling structure generally take the same form as the first
scaffold and first filling structure. A flowable polymer that may
be cured in situ may be used to as the filling material for both
the first and second filling structures.
[0027] The system may also comprise a releasable coupling mechanism
that is coupled with the first filling structure and the shaft. The
coupling mechanism is adapted to reduce axial movement along the
shaft of the filling structure relative to the scaffold. The
releasable coupling mechanism may comprise a tether that is
releasably coupled with the shaft and the filling structure. The
filling structure may also comprise a filling tube that is fluidly
coupled therewith and that is adapted to fill the filling structure
with the filling medium. The filling tube may also comprise an
inner tube that is slidably disposed in the filling tube. Both the
inner tube and the filling tube may be fluidly coupled with the
filling structure.
[0028] In another aspect of the present invention, a method for
treating an aneurysm comprises providing an elongate flexible shaft
having a proximal end and a distal end. The flexible shaft carries
a first double-walled filling structure and a first scaffold
adjacent the distal end. Advancing the elongate shaft in a
patient's vasculature allows the first double-walled filling
structure to traverse the aneurysm. Filling the first filling
structure with a fluid filling medium expands the filling structure
so that an outer wall of the first filling structure conforms to an
inside surface of the aneurysm and an inner wall of the first
filling structure forms a first substantially tubular lumen to
provide a first blood flow path across the aneurysm. Axially moving
the first scaffold relative to the first filling structure
positions at least a portion of the first scaffold within the first
substantially tubular lumen and radially expanding the first
scaffold expands the first scaffold from a contracted configuration
to an expanded configuration.
[0029] Axially moving the first scaffold may comprise moving the
first scaffold distally into the first lumen or axially moving the
first scaffold may comprise proximally retracting the first filling
structure over the first scaffold. Axially moving the first
scaffold may also comprise proximally retracting the first scaffold
into the first lumen or moving the first filling structure distally
over the first scaffold. Sometimes axially moving the first
scaffold may comprise guiding the first filling structure over a
tether line or pulling the first filling structure with a tether
line. The method may also include retracting a sheath from the
first filling structure or the first scaffolding so that that
portion is unconstrained from expansion. The method may also
comprise engaging a pusher tube with the first filling structure so
as to prevent motion thereof. The method may also further comprise
hardening the filling medium in the first filling structure.
[0030] The method may also include monitoring a pressure or
controlling the filling of the first or second filling structures
by changing pressure or volume of the filling medium. Filling the
filling structure may comprise controlling pressure and/or volume
of the filling medium. The pressure may be one that is exerted by
the filling medium within the first filling structure. The
monitored pressure may also be a pressure that is within a space
between an external wall of the first filling structure and a wall
of the aneurysm. Monitoring the pressure may include placing a
fluid filled balloon catheter or a pressure transducer in the space
between the filling structure and aneurysm wall. Often, the method
may further include regulating flow of the filling medium in
response to the monitored pressure.
[0031] Filling the filling structure may include actuating an
injection device and pressure may be monitored at a position
adjacent the injection device. The method also may include
relieving pressure in the filling structure with a relief valve
when the pressure exceeds a predetermined value. Sometimes, the
relief valve may be fluidly isolated from the first filling
structure. The fluid relieved from the filling structure may fill a
reservoir that is fluidly coupled with the relief valve and an
operator may observe the reservoir to determine inflation status of
the filling structure. Some pressure monitoring devices may include
a visual indicator that is coupled with the first filling
structure. The indicator may have a first and a second position,
and the indicator moves from the first position to the second
position when a predetermined pressure is applied to the indicator.
An operator may observe the indicator position to determine
fillings status of the filling structure.
[0032] Other embodiments may include positioning a collapsible
member such as a balloon between the outer wall of the filling
structure and the inside wall of the aneurysm. An operator observes
a compression mechanism having first and second positions that is
coupled with the filling structure. The compression mechanism
provides a predetermined force opposite to the force exerted by the
collapsible member as the filling structure is filled and the
compression mechanism moves from the first position to the second
position when the force exerted by the collapsible member exceed
the predetermined force. The compression mechanism may comprise a
spring and the collapsible member may be comprise a balloon.
[0033] The method may also include the step of stopping the filling
of the filling structure when the monitored pressure reaches a
predetermined pressure. Stopping filling may be achieved by
mechanically locking a filling device so that fluid may not be
delivered therefrom. Monitoring pressure may also include observing
the first scaffold. The first scaffold may have crushable regions
and remainder regions and the crushable regions collapse when the
filling structure is pressurized to a predetermined value while the
remainder regions remain fully expanded.
[0034] The method may further comprise providing a second elongate
flexible shaft having a proximal and distal end. The second shaft
carries a second double walled filling structure and a second
scaffold adjacent the distal end. Advancing the second elongate
shaft in the patient's vasculature allows the second double walled
filling structure to traverse the aneurysm. Filling the second
filling structure with a fluid filling medium expands the filling
structure so that an outer wall of the second filling structure
forms a second substantially tubular lumen to provide a second
blood flow path across the aneurysm. Filling the second filling
structure may also comprise controlling pressure or volume of the
fluid filling medium. Axially moving the second scaffold relative
to the second filling structure positions at least a portion of the
second scaffold within the second substantially tubular lumen and
radially expanding the second scaffold expands the scaffold from a
contracted configuration to an expanded configuration.
[0035] Axially moving the second scaffold may comprise moving the
second scaffold distally into the second lumen or proximally
retracting the second filling structure over the second scaffold.
Axially moving the second scaffold may also comprise proximally
retracting the second scaffold into the second lumen or moving the
second filling structure distally over the second scaffold.
[0036] The method may also comprise retracting a sheath from either
the second filling structure and/or the second scaffolding so that
either or both are unconstrained from expansion. Retracting the
sheath may also comprise splitting the sheath. The method also may
comprise hardening the fluid filling medium in the second filling
structure and monitoring a second pressure. The second pressure may
be exerted by the filling medium in the second filling structure.
Often, the flow of the filling medium may be regulated in response
to the second monitored pressure. In some embodiments, the method
may comprise filling either the first or the second filling
structure until it engages the other filling structure resulting in
filling medium being discharged from either the first or second
filling structure. In still other embodiments, the method may
comprise inflating a balloon on either the first or the second
elongate shaft so as to compress the first and second filling
structures against one another and against the aneurysm wall. Often
filling medium will be discharged from either the first or second
filling structure when the balloons are inflated. Radially
expanding any of the scaffolds may comprise inflating a balloon
disposed near the distal end of the shaft. The balloon may comprise
a pre-shaped, curved or tapered region.
[0037] The method may also comprise releasing a releasable coupling
mechanism that couples the filling structure with the shaft to
allow axial movement of the filling structure relative to the
scaffold and that also allows release of the filling structure from
the shaft. Releasing the coupling mechanism may comprise releasing
a knot in a tether joining the filling structure with the shaft. A
filling tube may be fluidly coupled with the filling structure and
the step of filling the filling structure may comprise passing
fluid filling medium through the filling tube to the filling
structure. The filling tube may comprise an inner tube that is
slidably disposed therein and that is also in fluid communication
with the filling structure. The method may comprise removing the
inner tube and passing additional fluid filling medium through the
filling tube after the inner tube has been removed.
[0038] In another aspect of the present invention, a system for
treating an aneurysm in a blood vessel comprises an elongate
flexible shaft having a proximal region and a distal region. An
expandable member is disposed adjacent the distal region and a
first expandable scaffold is disposed over the expandable member.
The first scaffold is radially expandable from a collapsed
configuration to an expanded configuration. A first double-walled
filling structure is disposed over the first scaffold. The filling
structure has an outer wall and an inner wall and the filling
structure is adapted to be filled with a hardenable fluid filing
medium so that the outer wall conforms to an inside surface of the
aneurysm and the inner wall forms a first substantially tubular
lumen to provide a path for blood flow. In the expanded
configuration, the first scaffold engages the inner wall of the
filling structure. A first releasable coupling mechanism releasably
couples the filling structure with the flexible shaft and the
coupling mechanism may comprise a tether that is releasably coupled
with the filling structure and the flexible shaft. The coupling
mechanism constrains axial movement of the filling structure
relative to the flexible shaft.
[0039] The first tether may comprise a suture, and in some
embodiments the system may include a lockwire disposed alongside
the flexible shaft. A distal end of the lockwire may be releasably
coupled with the flexible shaft. The flexible shaft may comprise a
tapered nosecone having an aperture therein and the nosecone may be
coupled with the distal region of the flexible shaft such that the
distal end of the lockwire may be releasably coupled with and
slidably received in the nosecone aperture. The first tether may be
releasably coupled to the lockwire. The filling structure may
include a first tether loop fixedly attached thereto, and the first
tether may pass through the tether loop. The first tether loop may
be disposed on a distal end of the filling structure. In some
embodiments, the first tether may be releasably coupled to the
lockwire with a knot such as a constrictor knot. One end of the
first tether may be fixedly attached with the flexible shaft.
[0040] The system may further comprise a second releasable coupling
mechanism. The second mechanism may comprise a tether that is
releasably coupled with the filling structure and the flexible
shaft. The second tether may be on an opposite end of the filling
structure as the first tether, and the second tether may constrain
axial movement of the filling structure relative to the flexible
shaft. The second tether may comprise a suture and may be
releasably coupled to the lockwire. The second tether may be looped
around the lockwire. In some embodiments, the filling structure
comprises a second tether loop fixedly attached thereto and
disposed on an opposite end as the first tether loop, and the
second tether may pass through the second tether loop. The second
tether may be coupled to the flexible shaft and may be releasably
coupled to the flexible shaft with a knot, such as a constrictor
knot.
[0041] The system may further comprise a second releasable coupling
mechanism, such as a tether that is releasably coupled with the
filling structure and the flexible shaft. The second tether may be
disposed on the same end of the filling structure as the first
tether, and the second tether may constrain axial movement of the
filling structure relative to the flexible shaft. The second tether
may comprise a suture. In some embodiments, the system may further
comprise a second lockwire disposed alongside the flexible shaft. A
distal end of the second lockwire may be releasably coupled with
the flexible shaft. The distal region of the flexible shaft may
include a tapered nosecone having a second aperture and the distal
end of the second lockwire may be releasably coupled with and
slidably received in the second nosecone aperture. The second
tether may be releasably coupled to the lockwire.
[0042] In some embodiments, the filling structure may comprise a
second tether loop fixedly attached thereto, and wherein the second
tether passes through the second tether loop. The second tether
loop may be disposed on the same end of the filling structure as
the first tether loop. The second tether may be releasably coupled
to the lockwire with a knot such as a constrictor knot. One end of
the second tether may be fixedly attached with the flexible
shaft.
[0043] The system may further comprise a filling tube fluidly
coupled with the filling structure. The filling tube may be adapted
to deliver the hardenable filling medium to the filling structure.
The filling tube may comprise a plurality of apertures near a
distal end thereof and that are adapted to allow the hardenable
filling medium to flow therethrough into the filling structure. The
filling tube may comprise an inner filling tube and an outer
filling tube slidably disposed thereover, both fluidly coupled with
the filling structure. A stylet may be disposed in the filling
tube. Some embodiments may include a filling tab fluidly coupled
with the filling structure and fluidly coupled with the filling
tube. The filling tab may comprise a scored region adapted to
permit separation of the filling tab into two portions, the first
portion remaining coupled with the filling structure after filling
thereof with the hardenable filling medium and the second portion
discrete and independent of the first portion.
[0044] In still other embodiments, the system may further comprise
an outer sheath having a lumen. The filling structure, the scaffold
and the expandable member may be disposed in the sheath lumen
during delivery of the system to a treatment site. Other
embodiments may include a second elongate flexible shaft having a
proximal region and a distal region and a second expandable member
disposed adjacent the distal region. A second expandable scaffold
may be disposed over the second expandable member. The second
scaffold may be radially expandable from a collapsed configuration
to an expanded configuration. The system may also include a second
double-walled filling structure disposed over the second scaffold.
The second filling structure may have an outer wall and an inner
wall, wherein the second filling structure is adapted to be filled
with a hardenable fluid filing medium so that the outer wall
conforms to an inside surface of the aneurysm and the inner wall
forms a first substantially tubular lumen to provide a path for
blood flow. The second scaffold in the expanded configuration may
engage the inner wall of the filling structure, and the system may
also have a tether releasably coupled with the second filling
structure and the second flexible shaft. The tether may constrain
axial movement of the second filling structure relative to the
second flexible shaft.
[0045] In yet another aspect of the present invention, a method for
treating an aneurysm in a patient comprises providing an elongate
flexible shaft having a proximal end, a distal end, and an
expandable member near the distal end. The flexible shaft carries a
first radially expandable scaffold over the expandable member and a
first double walled filling structure disposed over the first
scaffold. Advancing the shaft in the vasculature of the patient
allows the first filling structure to be delivered to the aneurysm.
Radially expanding the first scaffold expands the scaffold from a
contracted configuration to an expanded configuration, wherein in
the expanded configuration the first scaffold engages the inner
wall of the first filling structure. Filling the first filling
structure with a first fluid filling medium allows an outer wall of
the first filling structure to conform to an inside surface of the
aneurysm and an inner wall of the first filling structure forms a
first substantially tubular lumen to provide a first blood flow
path across the aneurysm. Filling the first filling structure with
the first fluid filling medium also allows assessment of the
filling volume by removing and recording the first filling medium.
Filling the first filling structure with a second fluid filling
medium allows an outer wall of the first filling structure to
conform to an inside surface of the aneurysm and an inner wall of
the first filling structure forms a substantially tubular lumen to
provide a first blood flow path across the aneurysm. The second
fluid filling medium is hardened in the first filling structure and
then the first filling structure is released from the flexible
shaft. The flexible shaft is then retracted away from the first
filling structure.
[0046] The method may further comprise pre-filling the first
filling structure with a pre-filling fluid until the outer wall of
the first filling structure conforms to the inside surface of the
aneurysm, thereby unfurling the first filling structure. The
pre-filling fluid may comprise saline and may be removed from the
first filling structure. The method may also comprise pre-filling
the first filling structure with pre-filling fluid until the outer
wall of the first filling structure conforms to the inside surface
of the aneurysm. The pressure and volume of the pre-filling fluid
used to pre-fill the first filling structure may be measured and
then the pre-filling fluid may be removed from the first filling
structure. Filling the first filling structure with the first fluid
filling medium may comprise filling the first filling structure
with the first filling medium using substantially the same pressure
and volume as measured. The pre-filling fluid may comprise saline
or contrast media to assist visualizing the filling process under
x-ray fluoroscopy. The first filling medium may be passed through a
filling tube that is fluidly coupled with the first filling
structure.
[0047] Radially expanding the scaffold may comprise inflating a
balloon that is disposed on the flexible shaft. Hardening the first
fluid filling medium in the first filling structure may comprise
polymerizing the first fluid filling medium in situ. The first
fluid filling medium may comprise polyethylene glycol.
[0048] A releasable coupling mechanism such as a tether may couple
the first filling structure with the flexible shaft and the step of
releasing the first filling structure from the flexible shaft may
comprise releasing the coupling mechanism or de-coupling the tether
from the first filling structure. One end of the tether may be
releasably coupled with a lockwire and the step of de-coupling the
tether may comprise retracting the lockwire thereby detaching the
tether from the lockwire. De-coupling the tether may comprise
releasing the tether from a tether loop on the first filling
structure. In some embodiments, a second releasable coupling
mechanism, such as a tether may couple the first filling structure
with the flexible shaft and the step of releasing the first filling
structure from the flexible shaft may comprise de-coupling the
second tether from the first filling structure. Releasing one or
more of the coupling mechanisms may permit separation of a filling
tube from the filling structure.
[0049] The method may further comprise the step of retracting a
sheath away from the first filling structure and the first scaffold
to allow expansion thereof. Pressure may be monitored during
filling of the first filling structure. The monitored pressure may
be a pressure of the filling medium in the first filling structure
or a pressure in a space between the outer wall of the first
filling structure and a wall of the aneurysm. A filling tube may be
released from the first filling structure after the hardenable
filling medium has been delivered thereto. Releasing the filling
tube may comprise severing a filling tab coupled with the first
filling structure.
[0050] In some embodiments, the method may further comprise
providing a second elongate flexible shaft having a proximal end, a
distal end, and a second expandable member near the distal end. The
second flexible shaft may carry a second radially expandable
scaffold over the second expandable member and a second double
walled filling structure may be disposed over the second scaffold.
The second shaft may be advanced in the vasculature of the patient
so that the second filling structure is delivered to the aneurysm
and the second filling structure is filled with a second fluid
filling medium so that an outer wall of the second filling
structure conforms to an inside surface of the aneurysm and an
inner wall of the second filling structure forms a second
substantially tubular lumen to provide a second blood flow path
across the aneurysm. The second scaffold is radially expanded from
a contracted configuration to an expanded configuration wherein in
the expanded configuration the second scaffold engages the inner
wall of the second filling structure. The second fluid filling
medium may be hardened in the second filling structure and the
second flexible shaft is released from the second filling
structure. The second shaft may be retracted away from the second
filling structure.
[0051] The first filling structure may comprise a filling tube that
is fluidly coupled therewith and the step of filling the first
filling structure may comprise passing filling medium through the
filling tube. The filling tube may comprise an inner tube that is
slidably disposed therein and that is also fluidly coupled with the
filling structure. The method may further comprise removing the
inner tube from the filling tube and supplying additional filling
medium to the filling structure by passing the filling medium
through the filing tube after the inner tube has been removed
therefrom.
[0052] These and other embodiments are described in further detail
in the following description related to the appended drawing
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 illustrates the anatomy of an infrarenal abdominal
aortic aneurysm.
[0054] FIG. 2 illustrates a delivery catheter carrying a single
prosthesis system which comprises a filling structure mounted over
a scaffold structure.
[0055] FIG. 3 illustrates a system comprising a pair of prostheses
for delivery to an infrarenal abdominal aortic aneurysm, where each
prosthesis comprises a delivery catheter carrying a filling
structure mounted over a scaffold structure.
[0056] FIGS. 4A-4I illustrate exemplary usage of the system in FIG.
3 for treating an infrarenal abdominal aortic aneurysm.
[0057] FIG. 5 illustrates an aneurysm treatment system having a
filling structure and scaffold concentric with a delivery
catheter.
[0058] FIG. 6 illustrates an aneurysm treatment system wherein the
filling structure is separate from the scaffold.
[0059] FIG. 7 shows an aneurysm treatment system having a filling
structure axially separated from the scaffold.
[0060] FIG. 8 illustrates an aneurysm treatment system similar to
that of FIG. 7, but with the relative positions of the filling
structure and scaffold reversed.
[0061] FIG. 9 illustrates an aneurysm treatment system having a
filling structure axially separated from the radially expandable
balloon.
[0062] FIGS. 10A-10B illustrate the use of various sheath
embodiments.
[0063] FIGS. 11A-11B show the use of a tether line to help guide
movement of the filling structure relative to the scaffold.
[0064] FIGS. 12A-12B show the use of a tether line to help pull the
filling structure toward the scaffold.
[0065] FIGS. 13A-13D illustrate the use of pressure monitoring to
facilitate filling of the filling structure.
[0066] FIG. 14A-14C illustrate the use of a pressure relief valve
and overflow reservoir.
[0067] FIGS. 15A-15B illustrate use of another pressure indicator
mechanism.
[0068] FIGS. 16A-16B illustrate pressure monitoring in the space
between the filling structure and the aneurysm wall.
[0069] FIGS. 17A-17C show a balloon catheter having various
pressure monitoring devices.
[0070] FIGS. 18A-18B illustrate a filling device with a locking
mechanism.
[0071] FIGS. 19A-19D illustrate various compartments in the filling
structure.
[0072] FIGS. 20A-20B illustrate the use of crumple zones in the
scaffolding as pressure indicators.
[0073] FIG. 21 illustrates an aneurysm treatment system with
integrated pressure monitoring.
[0074] FIGS. 22A-22B illustrate the use of a hitch to hold the
filling structure.
[0075] FIGS. 23A-23C illustrate a pocket feature on the filling
structure.
[0076] FIG. 24 shows an alternative embodiment of a filling
structure and scaffolding delivery system.
[0077] FIGS. 25A-25B illustrate the use of a pressure relief
valve.
[0078] FIGS. 26A-26C show the use of a stopcock.
[0079] FIGS. 27A-27B show how filling may be controlled with the
balloons on a delivery catheter.
[0080] FIGS. 28A-28B illustrate how filling may be controlled with
the filling structures themselves.
[0081] FIG. 29 illustrates the use of a tether to help minimize
relative movement between a filling structure and an endoframe.
[0082] FIGS. 30A-30B illustrate use of a constrictor knot.
[0083] FIG. 31 illustrates use of two tethers.
[0084] FIGS. 32A-32B illustrate positioning of a filling structure
relative to an endoframe.
[0085] FIG. 33 illustrates coupling of the filling structure with
the endoframe.
[0086] FIG. 34 illustrates the use of spring arms to help open a
portion of the filling structure.
[0087] FIG. 35 illustrates the use of a support post and
lockwire.
[0088] FIGS. 36A-36B illustrate use of a sheath.
[0089] FIGS. 37-38 illustrate still other embodiments using a
sheath.
[0090] FIGS. 39A-39C illustrate separation of the filling tube from
a filling structure.
[0091] FIG. 40 illustrates an embodiment of a filling tab.
[0092] FIGS. 41A-41B illustrate separation of a filling tube from
the filling structure.
[0093] FIG. 42 illustrates filling ports in the filling tube.
[0094] FIG. 43 illustrates separation of a filling tube from the
filling structure.
[0095] FIG. 44 illustrates blockage of a filling tube.
[0096] FIGS. 45A-45C illustrate the use of an inner and an outer
filling tube.
[0097] FIG. 46A-46C illustrate various filling tube geometries.
[0098] FIGS. 47A-47B illustrate an exemplary delivery system.
[0099] FIGS. 48A-48B illustrate the use of pressure monitoring
during treatment of an aneurysm.
[0100] FIG. 49 illustrates an exemplary embodiment of a delivery
system.
[0101] FIGS. 50A-50B illustrate various embodiments for introducing
contrast media.
[0102] FIGS. 51A-51B illustrate a pressure measuring device that
can mask pressure spikes.
[0103] FIGS. 52A-52D illustrate the use of a split sheath.
DETAILED DESCRIPTION OF THE INVENTION
[0104] FIG. 1 illustrates the anatomy of an infrarenal abdominal
aortic aneurysm comprising the thoracic aorta (TA) having renal
arteries (RA) at an 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).
[0105] Referring now to FIG. 2, a system 10 constructed in
accordance with the principles of the present invention for
delivering a double-walled filling structure 12 (also referred to
as an endograft in this disclosure) to an aneurysm includes the
filling structure 12 disposed over a radially expandable endoframe
27 (also referred to as a scaffold, stent or scaffolding in this
disclosure), both of which are then mounted on a delivery catheter
14 having an expandable element 16, typically an inflatable
balloon, at its distal end. Expandable element 16 traverses the
entire length of the endoframe 27 so that the endoframe 27 may be
radially expanded upon expansion of the expandable element 16.
Endoframe 27 traverses the entire length of filling structure 12
and most of endoframe 27 is covered by filling structure 12,
however endoframe 27 also has proximal and a distal regions that
extend uncovered beyond the filling structure 12. One of skill in
the art will appreciate that lengths of the filling structure,
endoframe and expandable element may be adjusted as required and
thus the relative lengths are not limited to those disclosed above.
Further details about the double-walled filling structure are
disclosed in U.S. Patent Publication No. 2006/0212112 (Attorney
Docket No. 025925-001610US) and preferred embodiments of an
endoframe scaffold are disclosed in U.S. Provisional Patent
Application No. 61/029,225 (Attorney Docket No. 025925-002710US)
and U.S. patent application Ser. No. 12/371,087 (Attorney Docket
No. 025925-002720US), both of which the entire contents are
incorporated herein by reference. The catheter 14 will comprise a
guidewire lumen 18, a balloon inflation lumen (not illustrated) or
other structure for expanding other expandable components, and a
filling tube 20 for delivering a filling medium or material to an
internal space 22 of the double-walled filling structure 12. The
internal space 22 is defined between an outer wall 24 and inner
wall 26 of the filling structure. Upon inflation with the filling
material or medium, the outer wall 24 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 correspondingly expand the endoframe 27 to
provide support and to shape an inner surface of the lumen 28. In
this embodiment, the expandable balloon is substantially
cylindrically shaped and therefore the lumen will also be
cylindrically shaped. In other embodiments, the balloon may be
pre-shaped to more precisely match the curvature of the vessel. For
example, when treating an aortic aneurysm, a tapered, pre-shaped or
curved balloon may be used so that the lumen substantially matches
the aorta. Various balloon configurations may be used in order to
match vessel tortuosity. Pre-shaped, curved or tapered balloons may
be used in any of the embodiments disclosed herein in order to
obtain a desired lumen shaped.
[0106] 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 FIG. 1. A system
comprising such a pair of filling structures is illustrated in FIG.
3 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 and each
system also has a radially expandable endoframe scaffold 127, 227.
The components of the filling structures 112 and 212, the
endoframes 127, 227 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 filling systems 112 and 212 will be given
identical numbers with either the 100 base number or 200 base
number. The filling structures 112 and 212 will generally be
positioned adjacent each other within the aneurismal space to fill
that space, as will be described with specific reference to FIGS.
4A-4I below.
[0107] FIGS. 4A-4I illustrate an exemplary use of the system in
FIG. 3 for treating an infrarenal abdominal aortic aneurysm AAA
with or without mural thrombus T. An optional sheath may be
disposed over the scaffold and/or filling structure as seen in FIG.
10A. In FIG. 4A a pair of guidewires (GW) will first be introduced
preferably percutaneously or by surgical cut down, from each of the
iliac arteries (IA) and advanced across the aneurysm toward the
renal arteries (RA). Referring now to FIG. 4B, the first delivery
catheter 114 having expandable balloon 116 will then be positioned
over one of the guidewires GW to position the double-walled filling
structure 112 across the aortic aneurysm (AAA) along with scaffold
127. The second delivery catheter 214 having expandable balloon 216
is then delivered over the other guidewire GW to position the
second filling structure 212 adjacent to the first structure 112
across the aneurysm (AAA) along with scaffold 227, as illustrated
in FIG. 4C. If either of the delivery catheters 114, 214 include
sheaths covering their respective scaffold and/or filling
structure, the sheath (not illustrated) will be retracted.
Typically, one of the filling structures 112, 212 and associated
balloons 116, 216 will be expanded first along with the
corresponding scaffold 127, 227, followed by the other filling
structure, scaffold and balloon. In some embodiments, both balloons
may be radially expanded simultaneously thereby also expanding the
filling structures and scaffolds simultaneously.
[0108] Alternatively, one or both filling structures 112, 212 may
be filled with a hardenable material and then the filling
structures 112, 212 are radially expanded along with the
corresponding scaffold 127, 227. In still other embodiments,
combinations of filling and expanding may be performed in different
order depending on physician preference and aneurysm anatomy. In
some embodiments, an optional unfurling of the filling structure
may be performed prior its filling and radial expansion. In this
optional step, once the delivery system is positioned across the
aneurysm, the filling structure may be filled with CO.sub.2 gas,
contrast media, saline or other fluids to unfurl the filling
structure away from the delivery catheter thereby helping to ensure
more uniform filling later on. During unfurling, the filling
structure may be partially filled or fully filled so that it
conforms to the inner aneurysm wall. Once unfurled, the fluid may
be removed from the filling structure and it may be filled with the
hardenable material to expand and conform to the aneurismal space
between the lumens and the inner aneurysm wall. Pressure relief
valves such as those described below may also be used to ensure
that the filling structure is not over filled.
[0109] In another variation of the method, an optional contrast
pre-filling step may be utilized. In this embodiment, after the
delivery catheter is positioned across the aneurysm and the
endoframe has been radially expanded, the filling structure may be
pre-filled with contrast media so as to permit observation of the
filled filling structure under a fluoroscope relative to the
aneurismal sac. Additionally, the pre-filling step allows the
physician to record the pressure and volume of the contrast media
used for optimal filling of the filling structure and this will
provide an estimate of volume and pressure to be used when filling
the filling structure with the hardenable filling material. In
order to prevent overfilling of the filling structure, any of the
pressure relief valves disclosed below may also be used to bleed
off excess fluid from the filling structure.
[0110] FIG. 4D illustrates inflation of balloon 116 along with
scaffold 127 in addition to expansion and filling of filling
structure 112. The filling structure 112 and balloon 116 are
expanded and inflated to fill generally half of the aneurismal
volume, as illustrated in FIG. 4D. Filling and expansion can
generally be carried out as described in U.S. Patent Publication
No. 2006/0212112 (Attorney Docket No. 025925-001610US) for one
filling structure, except of course that the filling structure 112
will be expanded to occupy only about one-half of the aneurismal
volume. U.S. Patent Publication No. 2006/0212112 discloses filling
of one filling structure in more detail including pressures,
filling materials and other details, the entire contents of which
have previously been incorporated herein by reference. After the
first filling structure 112 has been filled, the second filling
structure 212 may be filled and expanded along with scaffold 227,
as illustrated in FIG. 4E. FIG. 4E also illustrates a cut away view
of the expanded scaffolds 127, 227 within the filled filling
structures 112, 212. 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 artery, IA. The expanded scaffold
127 not only provides support to filling structure 112, but also
creates and shapes a lumen for blood passage from the aorta to one
of the iliac arteries. Similarly, expanded scaffold 227 also
provides a lumen for blood passage from the aorta into the other
iliac artery. In some protocols filling of the filling structures
(either both filled simultaneously or one after the other) may be
performed before, during or after radial expansion of the balloons
and the scaffolding 127, 227 (either both expanded simultaneously
or one after the other). Additionally, as discussed above with
respect to FIG. 2, the scaffolds 127, 227 may be radially expanded
using a cylindrically shaped balloon to form a substantially
cylindrically shaped lumen. Curved, tapered or pre-shaped balloons
may also be used to expand the scaffolds 127, 227, thereby forming
a lumen that also is curved, tapered or shaped. The curved, tapered
or pre-shaped balloon may be selected to match the anatomy of the
vessel in which the scaffold and endograft is placed. Pre-shaped,
curved or tapered balloons may be used in any of the other
embodiments disclosed herein in order to obtain a desired lumen
shape.
[0111] After filling the filling structures 112 and 212 as
illustrated in FIG. 4E, the filling materials or medium will be
cured or otherwise hardened as described in U.S. Patent Publication
No. 2006/0212112 and the delivery catheters 114 and 214 removed,
respectively. The hardened filling structures along with the
expanded scaffolds 127, 227 will then provide a pair of tubular
lumens opening from the aorta beneath the renal arteries to the
right and left iliac arteries, as shown more clearly in broken line
in FIG. 4F. The ability of the filling structures 112 and 212 to
conform to the inner surface (S) of the aneurysm, as shown in FIG.
4F, helps the structures to remain immobilized within the aneurysm
with little or no migration. Immobilization of the filling
structures 112 and 212 may be further enhanced by providing any of
the surface features described in U.S. Patent Publication No.
2006/0212112 which has been incorporated herein by reference.
[0112] The double filling structure embodiments will include at
least one separate scaffold deployed within each of the tubular
blood flow lumens. The scaffolds will generally be endoskeletal
structures that lay the foundation for new lumens, and will be
deployed within the tubular lumens of the double-walled filling
structures using balloon or other expansion catheters (in the case
of malleable or balloon-expandable scaffolds) and an optional
retractable constraining sheath. FIG. 4G more clearly shows the
first scaffold 127 disposed within the tubular lumen of the first
filling structure 112 while a second scaffold 227 is disposed in
the tubular lumen of the second filling structure 212. As
illustrated, in this exemplary embodiment, the scaffolds are
balloon expandable structures which extend into the iliac arteries
IA at the lower end of the filling structures. In other
embodiments, the scaffolds may be self-expanding stent-like
structures fabricated from a shape memory alloy such as
Nitinol.
[0113] Referring now to FIG. 4H, first and second scaffolds 127 and
227 may extend upwardly on the aortic side of the first and second
filling structures 112 and 212. When the scaffold structures extend
into the thoracic aorta TA, it will usually be desirable that they
be expanded so that they conform to each other along a plane or
region of contact. For example, as shown in FIG. 4I, the upper ends
of the scaffolds 127, 227 may be formed preferentially to have
D-shaped cross-sections when expanded, although other
cross-sections such as elliptical, circular, etc. may be formed.
Thus, flat faces 258 and 260 will engage each other with the
remaining portion of the stent conforming to the inner wall of the
aorta. In this way, most of the cross-sectional area of the aorta
will be covered with the scaffold, thus enhancing blood flow
through the filling structures. Other configurations are disclosed
in U.S. Patent Publication No. 2006/0212112 previously incorporated
herein by reference.
[0114] In the exemplary embodiment of FIGS. 4A-4I, the scaffold and
filling structure are both disposed coaxially and generally
concentrically over an expandable member coupled to a delivery
catheter and the entire system is delivered to the aneurysm at one
time. FIG. 5 shows a similar coaxial and concentric system 300 for
treating aneurysms where a filling structure 308, also referred to
as an endograft is coaxially disposed over stent-like scaffold 306,
both of which are then coaxially and concentrically positioned over
a radially expandable balloon 304 which is coupled to the distal
region of a catheter shaft 302. Proximal and distal portions of
scaffold 306 extend uncovered by filling structure 308 and a
filling tube 310 allows a fluid to be delivered to the filling
structure 308. While this embodiment is promising, in certain
situations, the filling structure may move relative to the
endoframe during delivery, thereby resulting in inaccurate
placement of one or both devices. It would therefore be
advantageous to provide a more effective way of coupling the
filling structure with the endoframe to minimize such movement and
to facilitate more accurate delivery of the scaffold and endograft
to the treatment site. FIG. 29 illustrates an exemplary embodiment
that employs a releasable coupling mechanism to help minimize such
movement. In FIG. 29, the distal region of a delivery catheter
having a filling structure and an endoframe disposed thereover is
highlighted. Filling structure 2902 is disposed over an endoframe
2904, both of which are also disposed over a radially expandable
balloon 2906 coupled to catheter shaft 2908. The distal end of
catheter shaft 2908 includes an atraumatic tapered nosecone 2910
having a receiving aperture 2920. The releasable coupling mechanism
includes a lockwire 2918 that runs substantially parallel with
catheter shaft 2908, with the distal end of the lockwire 2918
disposed in the receiving aperture 2920 in nosecone 2910. The
releasable coupling mechanism also uses a tether 2914. Tether 2914
is releasably coupled with the lockwire 2918, the filling structure
2912 and the catheter shaft 2908, thereby minimizing relative
motion of the endoframe 2904 to the filling structure 2902 during
delivery. The tether may be a thin wire fabricated from metal or a
polymer or it may be a suture or other filament-like material.
Coupling is accomplished by passing one end of the tether 2914
through a tether loop 2912 attached to the filling structure 2902
and one end of the tether is then releasably coupled with the
lockwire 2918 using a releasable knot, here a constrictor knot
2916. Constrictor knots are well known in the art and may be seen
in greater detail in FIGS. 30A-30B. The opposite end of the tether
is secured to the distal region of the delivery catheter 2922 with
a knot such as a constrictor knot, or bonded, welded or otherwise
fixed to the catheter shaft. This configuration helps keep the
filling structure 2902 from moving relative to the endoframe 2904
and the delivery catheter 2908 during delivery. FIG. 29 illustrates
a single tether coupled with a single tether loop. Using the
tether/pullwire coupling system, movement of the filling structure
relative to the endoframe is limited to .+-.5 mm preferably, and
more preferably to .+-.3 mm and the endoframe/filling structure can
be positioned in the aneurysm to within .+-.7 mm of a target
implantation site, and more preferably to within .+-.5 mm of the
target site.
[0115] In use, once the filling structure 2902 and the endoframe
2904 have been delivered to a desired position, the lockwire 2918
may be retracted proximally so that its distal tip disengages from
aperture 2920 and the lockwire is removed from under the
constrictor knot 2916 allowing the knot to unfurl. This de-couples
the endoframe 2902 from the delivery catheter 2908 so that the two
may be separated from one another. One end of the tether remains
coupled with the catheter so that the tether may also be removed
from the body.
[0116] The embodiment of FIG. 29 only illustrates a single tether.
In other embodiments, multiple releasable coupling mechanisms using
tethers may be coupled with multiple tether loops. For example,
two, three, four or more releasable coupling mechanisms having two,
three, four or more tethers may be disposed circumferentially and
optionally symmetrically around the catheter and filling structure
coupled with a matching number of tether loops coupled with the
filling structure. In other embodiments, one, two, three, four, or
more releasable coupling mechanisms using tethers may be coupled to
both the proximal and distal ends of the filling structure with
tether loops on the proximal and distal ends of the filling
structure. FIG. 31 illustrates an exemplary embodiment of a device
having two releasable coupling mechanisms including tethers. In
FIG. 31 a delivery sheath 3102 is disposed over the endoframe 3118
and filling structure 3104 during delivery to the aneurysm,
typically over a guidewire GW. Once delivered to the aneurysm, the
endoframe 3118 and the filling structure 3104 are advanced and
exposed from the delivery sheath 3102 (or the delivery sheath is
retracted). Two releasable coupling mechanisms having two tethers
3110 and 3128 are used to help couple the filling structure 3104
with the endoframe 3118. A first tether 3110 passes through a
tether loop 3122 attached to the filling structure 3104 while one
end of the tether is releasably connected to the lockwire 3108
using a knot 3124 such as the constrictor knot previously disclosed
above. The other end 3114 of the tether 3110 is coupled with a
distal portion of delivery catheter 3116 or nose cone 3106. A
second tether 3128 passes over the lockwire 3108 and through a
second tether loop 3126 attached to the other end of the filling
structure 3104. The second tether 3128 is then releasably coupled
with the fill tube 3132 extending from the filling structure 3104
using a knot 3130 such as a constrictor knot. The fill tube 3132
allows the filling structure 3104 to be filled with hardenable
medium from outside the patient's body. The lockwire 3108 runs
substantially parallel with the delivery sheath 3102 and is
disposed under the filling structure 3104. The distal end of the
lockwire 3108 is releasably received in an aperture 3112 in tapered
nosecone 3106 and the proximal end may be manipulated by the
physician from outside the patient's body. In addition to helping
prevent movement of the filling structure relative to the scaffold,
the second tether 3128 helps to prevent release of the fill tube
3132 from the filing structure 3104, thus providing a fail safe
mechanism prior to filling, and during filling or re-filling of the
filling structure and until the procedure is over and it is desired
to separate the filling tube from the filling structure. Endoframe
3118 is crimped over balloon 3120 which is coupled with the
delivery catheter shaft 3116. In these exemplary embodiments, a
tether is used in the releasable coupling mechanism to prevent
unwanted movement of the filling structure relative to the
scaffold. One of skill in the art will appreciate that other
releasable coupling mechanisms may be used and therefore the
coupling mechanism is not limited to tether embodiments.
Additionally, the tether may be used as a releasable coupling
mechanism in any of the embodiments disclosed in this
specification.
[0117] The coupling mechanism described in FIG. 31 also allows
positioning of the filling structure relative to the endoframe by
movement of the delivery catheter, as illustrated in FIGS. 32A-32B.
In FIG. 32A, depending on how taut the tethers 3110 and 3128 are,
the delivery catheter 3116 may be advanced or retracted as
indicated by the arrows to position the endoframe 3118 and delivery
catheter 3116 relative to the filling structure 3104. Similarly, in
FIG. 32B, the delivery catheter 3116 may be advanced into the
filling structure 3104 or retracted away from the filling structure
3104 as indicated by the arrows. This embodiment may be used when
in situ adjustment is desired or during "serial deployment" where
either the filling structure or the endoframe is deployed before
the other and then the two components are aligned in the aneurysm,
as will be discussed in greater detail below. In addition to serial
delivery of a scaffold and endograft, the releasable coupling
mechanisms described herein (e.g. the tether embodiments described
above) may also be used in parallel delivery of the two components
as will be discussed in greater detail below. Thus, releasable
coupling mechanisms such as tethers may be used in any of the
embodiments disclosed herein. Sometimes, the lockwire will be
covered with a support post. In FIG. 35, a loop 3514 coupled with
the filling structure 3502 is fed into an aperture 3516 of a
support post 3512. A lockwire 3510 is fed through the support post
3512 and through the loop 3514, thereby coupling the filling
structure 3502 with the lockwire 3510. The distal end of the
lockwire 3510 is received in an aperture 3508 on nosecone 3506 of
the delivery catheter 3504. This configuration prevents the support
post from having a free end that could extend and cause damage or
trauma to the vasculature. Retraction of the lockwire 3510 past the
aperture 3516 releases the loop 3514 from the lockwire 3510.
[0118] In other embodiments, the filling structure may be coupled
more directly with the endoframe. For example, in FIG. 33, the
endoframe 3304 includes eyelets 3306 near it's proximal and distal
ends. Tether loops 3308 may then be looped through the eyelets 3306
and secured to the filling structure 3302. This way, the filling
structure 3302 will be fixed relative to the endoframe as long as
the tether loops are taut. Generally, this coupling mechanism will
allow about .+-.5 mm and more preferably .+-.3 mm of relative
movement between the filling structure and the endoframe. Also, the
filling structure and endoframe should be positionable within .+-.7
mm and more preferably between .+-.5 mm of a target position within
the aneurysm of the filling structure 3302.
[0119] In place of tethers coupled with the filling tube (such as
tether 3128 in FIGS. 32A-32B), spring loaded arms may be used. In
FIG. 34, filling structure 3402 includes a filling tube 3410 for
filling the filling structure with hardenable medium. A pair of
spring arms 3414 are coupled with the filling tube 3410 at one end,
and the opposite ends of the arms 3414 are coupled with the filling
structure 3402. The ends are wrapped around a loop 3412 coupled
with the filling structure 3402. In this embodiment, the arms are
wire-like elements made from spring temper metal such as stainless
steel or superelastic nitinol, although other materials could be
used such as a resilient polymer. Since the filling structure is
coupled with the filling tube, they are fixed to one another and
relative movement is not possible. The arms 3414 are advantageous
since upon deployment from a constraining sheath (not illustrated),
the arms radially expand outward, facilitating opening of the
filling structure so it is may receive the delivery catheter 3406
having an endoframe 3404 mounted over a balloon 3408. Again, this
embodiment may be used when the filling structure and the endoframe
are delivered separately, as discussed below.
[0120] In addition to the potential challenge of minimizing
movement of the endoframe relative to the filling structure, the
embodiment described in FIG. 5 may present other challenges. For
example, because of the stackup of multiple elements on top of one
another, the distal region of system 300 has a relatively large
profile which can make it difficult to insert percutaneously into
the patient's vasculature and in some cases (e.g. through tortuous
vessels or through stenotic regions) it also is difficult to
advance to the aneurysm. Therefore, other delivery system
configurations are possible which may help reduce profile and
facilitate delivery. These delivery systems have an outer diameter
preferably ranging from 10 French to 18 French, and more preferably
have an outer diameter ranging from 12 French to 16 French.
[0121] FIG. 6 illustrates an alternative embodiment where the
system 320 utilizes independent delivery of the filling structure
and the scaffold. In FIG. 6, a filling structure 326 is disposed
over a balloon 324 which is coupled to a first delivery catheter
322. A filling tube 328 allows the filling structure 326 to be
filled with a hardenable material. A second delivery catheter 330
carries a second balloon 332 having a scaffold 334 disposed
thereon. In this embodiment, the endograft may be delivered to the
aneurysm first where it is expanded and filled via filling tube 328
and then the first catheter 322 is removed from the filling
structure 326. The second catheter 332 is then advanced into the
lumen created by the filling structure 326 and then balloon 332 is
expanded thereby correspondingly expanding scaffold 334 within
filling structure 326. Alternatively, after filling structure 326
has been expanded and filled, delivery catheter 322 may be removed
from the patient's body and scaffold 334 may be mounted on the same
delivery catheter 322 for delivery and expansion into the filling
structure 326. This alternative embodiment provides some advantages
over the embodiment of FIG. 5 such as having a lower profile but
still has challenges such as the increased cost and waste
associated with using two separate delivery catheters or an
increased procedure time to deliver and deploy the filling
structure and scaffold independently of one another. One possible
solution is to provide a delivery catheter having two independently
expandable balloons disposed on a delivery catheter. The balloons
are separated from one another by a predetermined distance. A
scaffold is placed over one balloon and an endograft is placed over
the second balloon. Thus, a single catheter may be used to deliver
both the graft and scaffold to the aneurysm where the graft and
scaffold are then independently deployed into the aneurysm.
[0122] Another embodiment which reduces the need for two delivery
catheters and also reduces procedure time by eliminating the need
to remove the catheter from the patient and then mount a scaffold
thereover is illustrated in FIG. 7. In FIG. 7, a single delivery
catheter carries both scaffold and filling structure to the
aneurysm while still providing a system with reduced delivery
profile. Delivery system 350 includes a delivery catheter 352
having an expandable balloon 358. Scaffold 360 is mounted directly
over the balloon 358 and the filling structure 354 is positioned
distal to the scaffold 360 such that the two implants are axially
separated from one another and a gap or spacing 362 separates them.
The releasable coupling mechanisms described above, including the
tether embodiments may be used to limit movement between the
scaffold and the filling structure. The delivery catheter 352 may
be advanced to the aneurismal treatment site such that filling
structure 354 traverses the aneurysm. The filling structure 354 may
be filled via filling tube 356 so that it conforms to the aneurysm
and then scaffold 360 may be advanced distally in the direction of
arrow 364 so that is received in the lumen of filling structure
354. Balloon 358 may then be radially expanded so as to expand
scaffold 360 into the inner wall of filling structure 354. In an
alternative embodiment, after filling structure 354 is positioned
across the aneurysm, scaffold 360 may be advanced into the lumen of
filling structure 354. Both are then radially expanded by expansion
of balloon 358 and the filling structure is filled either before,
during or after radial expansion. System 370 of FIG. 8 is similar
to that of system 350 in FIG. 7 except that the relative positions
of the scaffold 360 and filling structure 354 have been reversed.
This time, in the embodiment of FIG. 8, scaffold 360 is retracted
proximally in the direction of arrow 366 into the lumen of filling
structure 354. One of ordinary skill in the art will appreciate the
motion of the components is relative, thus instead of advancing a
first component into a second component, the second component may
be retracted over the first component. Similarly, retraction of a
first component into a second component may also be achieved by
advancing the second component over the first component.
[0123] Yet another embodiment that helps reduce delivery profile is
illustrated by system 390 in FIG. 9. In FIG. 9, a filling structure
392 having filling tube 398 is disposed over delivery catheter 396
and axially separated from radially expandable balloon 394 by a
spacing 399. In this embodiment, the filling structure 392 may be
delivered to the aneurysm where it is filled and balloon 394 is
expanded to help form the lumen in filling structure 392.
Alternatively, the filling structure may be retracted over balloon
394 either before, during or after delivery to the aneurismal
treatment site and then it may be expanded and filled. A separate
scaffold (not illustrated) may then be delivered and deployed in
the lumen created by the inner wall of filling structure 392. A
releasable coupling mechanism, such as the tether embodiments
previously described above may also be included in this embodiment
to minimize movement of the filling structure relative to the
scaffold.
[0124] Some delivery systems may include a sheath. Any of the
embodiments previously described may include a sheath in order to
protect the scaffolding and/or the filling structure. In some
embodiments where the scaffolding is self-expanding, the sheath
acts as a constraint to keep the scaffolding from self-expanding.
FIG. 10A illustrates a delivery system having a balloon 406
disposed over a catheter shaft 404. A balloon expandable
scaffolding 408 is disposed over the balloon 406 and a filling
structure 410 is also disposed over the catheter shaft 404 axially
separated from the balloon 406. An outer sheath 402 is disposed
over both the scaffolding 408 and the filling structure 410. Moving
the sheath 402 away from the scaffolding 408 exposes the
scaffolding 408 and/or filling structure 410 so that either may be
radially expanded by balloon 406 or allows expansion of filling
structure 410 due to filling. FIG. 10A also illustrates an optional
pusher tube 412 having a distal end that can engage the proximal
end of the endograft. The pusher tube keeps the endograft from
moving as the outer sheath 402 is retracted and also helps to
support the endograft and prevent it from collapsing during sheath
retraction. The pusher tube 412 and the sheath 402 may be extruded
using manufacturing techniques well known to those of ordinary
skill in the art and may be fabricated from a number of polymers
such as polyethylene, polyurethane, Teflon, PVC, nylon and the
like.
[0125] FIG. 10B illustrates another sheath embodiment similar to
the embodiment of FIG. 10A, except in this embodiment the sheath
has a tapered distal end. Because the balloon 406 and scaffolding
408 are distal relative to the filling structure 410 and because of
the larger profile of the endograft filling structure 410 relative
to the scaffolding 408, a step exists between the filling structure
410 and the scaffolding 408. Tapered region 403 in sheath 402
provides a smoother transition between these two regions. In order
to facilitate retraction of the sheath over the filling structure
410, the tapered tip 403 may be perforated or longitudinally slit.
Thus, as sheath 402 is retracted and as the tapered region 403
begins to engage filling structure 410, the slits or perforations
will open up allowing the smaller diameter sheath tip to pass over
the filling structure 410. In a preferred embodiment, two slits
approximately 180 degrees apart may be imparted into the sheath
tip, although it will be recognized that additional slits or even a
single slit may be used.
[0126] Other variations on the orientation of the balloon, filling
structure and scaffolding may also be employed. For example, in
some embodiments the endoframe scaffolding and filling structure
may be mounted coaxially over a catheter shaft either proximal of
or distal to a balloon. The scaffolding and filling structure are
positioned at the treatment site and then the balloon is positioned
within the scaffolding and filling structure and expanded. In a
variation of this embodiment, a thin split tubular liner may be
positioned over the balloon and passes through the inner diameter
of the filling structure. The thin liner acts as a guide for the
balloon during use. Thus, as the balloon is axially positioned
within the scaffolding and filling structure, the thin liner guides
the balloon through the inner diameter of the scaffolding. When the
balloon is expanded, the thin liner splits along perforations or
slit regions to allow radial expansion thereof.
[0127] For example, in FIGS. 36A-36B, a smooth sheath or covering
3608 may be disposed over all or a portion of the endoframe 3606
and balloon 3610. This is useful in embodiments where the endoframe
3606 and catheter shaft 3604 are advanced into the filling
structure 3602 (e.g. FIG. 7) or where the endoframe 3606 and
catheter shaft 3604 are retracted into the filling structure (e.g.
FIG. 8). Covering all or a portion of the balloon 3610 and
endoframe 3606 allows both to easily be received into the filling
structure 3602 without binding or damaging either component. When
the balloon is inflated, the cover 3608 will be pushed away from
and off the endoframe 3606 and balloon 3610, allowing full
expansion as seen in FIG. 36B.
[0128] FIG. 37 illustrates another embodiment using a sheath or
cover. In FIG. 37, the entire endoframe 3704 and balloon 3708 are
covered by the sheath 3702 to facilitate smooth entry of the
endoframe 3704 into the filling structure 3706 when the catheter
shaft 3710 is moved in the direction of the arrow. FIG. 38
illustrates still another embodiment using a sheath. In FIG. 38, a
sheath or sleeve 3802 not only covers the endoframe 3804 and
balloon 3808, but extends all the way through the filling structure
3810. Thus, when the delivery catheter 3806 is advanced, the
endoframe 3804 easily slides through the sleeve 3802 and avoids
rubbing against the inner wall of the filling structure 3810. The
sleeve 3802 may then be easily retracted and removed prior to
deployment of the endoframe and filling structure.
[0129] A split sheath or a perforated sheath may also be used to
facilitate deployment of the device. For example, FIG. 52A
illustrates a filling structure 5210 having a filling tube 5214
disposed over a scaffold 5212 which is carried by a balloon 5208 on
a delivery catheter shaft 5206 having a distal nosecone 5204. The
delivery catheter is delivered over a guidewire GW and covered with
a sheath 5202 during delivery. Upon deployment, the sheath 5202 is
retracted and the filling structure 5210 is filled and endoframe
5212 is expanded with balloon 5208. The delivery catheter 5206 is
then retracted away from the expanded endoframe 5212 and expanded
filling structure 5210 as seen in FIG. 52B. In some situations, the
physician may desire to further expand the endoframe 5212 with a
larger size balloon. This requires that the delivery catheter 5206
be removed and replaced. However, the nosecone 5204 cannot be
retracted into the sheath 5202 due to interference with the filling
tube 5214. A tapered split sheath or a tapered perforated sheath
may be used to overcome this challenge. FIG. 52C illustrates a
tapered split sheath 5216. The tapered split sheath 5216 allows for
a smaller nosecone 5204, which can pass through the sheath. Because
the sheath 5216 is tapered at the tip, it must split to pass over
the filling structure 5210. This allows the delivery catheter to be
retracted from the patient and replaced with a different catheter
having a different balloon size for post-dilation of the
endoframe.
[0130] In other embodiments, a tether line may be used to help
guide movement of the filling structure relative to the
scaffolding. FIGS. 11A-11B illustrate the use of such a tether
line. In FIG. 11A, a delivery system 420 includes an elongate
flexible shaft 422 having a balloon 430 disposed near the distal
end of the shaft 422. A stent-like scaffolding 432 is carried by
the balloon 430. A filling structure 436 with filling tube 438 is
also disposed over shaft 422. Filling structure 436 has four
eyelets 434 which serve as guides for tether lines 428 to pass
through. Tether lines 428 extend from the proximal end of delivery
system 420, through eyelets 434 and are coupled to nosecone 426.
Nosecone 426 is coupled to shaft 424 which is movable relative to
shaft 422. Shaft 422 is retracted over shaft 424 such that balloon
430 and scaffold 432 are slidably received by filling structure
436. FIG. 11B shows retraction of scaffolding 432 into filling
structure 436 with a longer length of shaft 424 exposed. Tether
lines 428 help guide the filling structure 436 so that it mates
with scaffolding 432 and is retracted into the filling structure
432. In this exemplary embodiment, four eyelets 434 are used,
although more or less may also be used. The eyelets 434 may be
integral with the filling structure 436 or they may be separate
components bonded or otherwise attached thereto. Once the
scaffolding has been retracted into a desired position within
filling structure 436, the tether lines 428 may be pulled from
nosecone 426 and away from the filling structure 436 so that it may
be expanded and filled in the aneurysm.
[0131] FIGS. 12A-12B illustrate an alternative embodiment of a
system 450 employing tether lines. In FIGS. 12A-12B, tether lines
are used to pull the filling structure toward the scaffolding so
that the two components are properly aligned. In FIG. 12A, a
catheter shaft 456 carries a balloon 460 disposed near the shaft's
distal end and a scaffolding 462 is disposed over the balloon. A
nosecone 454 is coupled to the distal end of shaft 456 and a
filling structure 452 having a filling tube 464 is disposed over
the catheter shaft adjacent the balloon 460 and scaffold 462. The
nosecone has a taper 457 on the proximal end as well as an optional
taper on the distal end, that way the nosecone helps guide the
catheter as it is being advanced through the vasculature and the
proximal taper helps the catheter pass through the filling
structure as the catheter is being retracted away from the filling
structure. Tether lines 458 are removably coupled to filling
structure 452 and extend distally to nosecone 454. Tether lines 458
extend through nosecone 454 and then extend proximally through a
lumen in shaft 456 (not shown) until the tether lines 458 exit the
proximal end of the catheter shaft 456. As the proximal portion of
tether lines 458 are pulled proximally away from the aneurysm,
filling structure 452 is advanced until it is properly positioned
over the scaffolding 462 and balloon 460. The tether lines may then
be pulled free from filling structure 452 and pulled into nosecone
454 as seen in FIG. 12B. The filling structure 452 and scaffold 462
may then be filled and expanded into the aneurysm. In an
alternative embodiment, the shaft 456 and scaffolding 462 may be
retracted into filling structure 452.
[0132] A hitch may also be used to move the filling structure
relative to the scaffolding. FIGS. 22A-22B illustrate an exemplary
embodiment of a hitch. In FIG. 22A eyelet or suture loop 702 is
coupled with a filling structure 712 (FIG. 22B). Here, one loop is
disclosed, although additional suture loops may also be used. The
suture loop 702 is used to hitch the filling structure 712 with a
hypotube 760 so that the filling structure may be advanced.
Hypotube 706 runs substantially parallel with the delivery catheter
shaft (not illustrated here). A distal portion of the hypotube 706
is skived 708 to create a receptacle for receiving the suture loop
702. A lockwire 704 passes through the hypotube 706 and through the
suture loop 702, thereby locking the suture loop 702 to the
hypotube 706. When the hypotube 706 is advanced distally suture
loop 702 is tensioned and thus, the filling structure may be
advanced distally over the scaffolding 710. Once the filling
structure 712 is placed in the desired position relative to
scaffolding 710, the lockwire 704 may be retracted proximally from
the hypotube 706 releasing the suture loop 702 from the skived
region 708. The hypotube 706 and lockwire 704 may then be retracted
away from the filling structure 712 and removed from the
patient.
[0133] Sometimes, it may be desirable to increase the columnar
strength of the endograft in order to prevent it from buckling or
otherwise collapsing. Suturing the endograft to the scaffold may be
used to help keep the two structures coupled together. Some
embodiments utilize wires or metal frames in the filling structure
or attached thereto in order to provide additional support. A
pocket or receptacle on the filling structure may also provide
enhanced column strength. FIGS. 23A-23C illustrate an exemplary
embodiment with a pocket.
[0134] In FIG. 23A, filling structure 730 comprises a pocket or
receptacle formed in a wall of the filling structure 730, near its
distal end. The pocket 734 may be made from the same material as
the filling structure 730, or it may be another resilient material.
The pocket 734 is generally closed along three sides and has one
end open, preferably proximally oriented. The opening is sized to
slidably receive a tensioning tube, rod or hypotube 732. In use,
the tensioning tube 732 is inserted into the pocket 734 until it's
distal end bottoms out. FIG. 23B shows the tensioning tube 732
traversing the unrolled, flattened filling structure 730
substantially parallel to the longitudinal axis thereof. A filling
tab 736 is coupled with a proximal end of the filling structure 730
and a filling tube 738 is fluidly connected to the filling tab 736.
The filling tube 738 extends proximally so that the filling
structure 730 may be filled from outside the patient's body. The
filling tube 738 may be used to apply tension to the proximal end
of the filling structure 730 and thus the filling structure 730 is
captured between the pocket 734 on the distal end of the filling
structure 730 and the filling tube 738 on the proximal end. In an
alternative embodiment, the proximal end of the filling structure
730 may utilize the hitch previously disclosed in FIGS. 22A-22B.
FIG. 23C shows a pocket 734 on the distal end of filling structure
730 and a suture loop 740 on the proximal end of filling structure
730. Tensioning tube 732 is inserted into pocket 734 and also uses
the hitch of FIGS. 22A-22B to capture suture loop 740. In either
embodiment, once the filling structure is delivered to the
treatment site, filled and deployed, the tensioning tube 732 may be
retracted from the pocket 734 and the hitch released, thereby
disengaging the tensioning tube 732 from the filling structure
730.
[0135] Another exemplary embodiment of a filling structure and
scaffolding delivery system is seen in FIG. 24. In FIG. 24, a
delivery catheter has a nosecone 752 attached to a center shaft 758
via a tip 754 member. An endograft filling structure 756 is
positioned coaxially over the center shaft 758. Also coaxial to the
center shaft 758 and proximal to the filling structure 756 is a
sliding shaft 764 which can slide axially along the center shaft
758. Attached distally to the sliding shaft 764 is an expandable
member 760, here a balloon, which has a stent-like scaffolding 762
crimped thereover. Coaxial to both shafts 758, 764 is an outer
sheath 766 which has an inner diameter large enough to contain both
shafts 758, 764, the balloon 760, scaffolding 762 and filling
structure 756. A pullwire 768 runs substantially parallel to the
longitudinal axis of the shafts 758, 764, outside of the balloon
760 and scaffolding 762 and through the inner diameter of the
filling structure 756. The pullwire 768 is removably coupled to the
filling structure 756 at two or more positions. In use, the outer
sheath 766 is retracted to expose the filling structure 756. The
balloon 760 and scaffolding 762 are advanced over the center shaft
758 by advancing the sliding shaft 764, through the inner diameter
of the filling structure 756 until the balloon 760 and scaffolding
762 are axially aligned with the filling structure 756. The balloon
760 may then be inflated, radially expanding the scaffolding 762
within the filling structure 756. The filling structure 756 may
then be filled with a hardenable material and the pullwire 768 is
retracted to release the filling structure 756 from the shaft 758
and the delivery catheter may then be removed from the patient.
[0136] Many of the filling structure embodiments include a filling
tube. FIG. 41A illustrates an embodiment where a single lumen
filling tube 4106 may extend from the filling structure 4102
proximally so that the filling structure may be filled with a
hardenable medium by a physician using a syringe, pump or other
filling device. Once the filling structure is filled with
hardenable medium 4104, the filling tube 4106 may be retracted and
pulled away from the filling structure 4102. In some circumstances,
the hardened filling medium 4104 may form a plug or tail 4108 that
extends outside of the filling structure 4102. This is undesirable
since the tail 4108 could break free and migrate or it could
puncture or otherwise cause trauma to adjacent tissue. FIG. 41B
illustrates the remaining tail 4108 after the filling tube 4106 has
been released from the filling structure 4102. One embodiment that
minimizes or eliminates this challenge is seen in FIG. 42. In FIG.
42, the distal portion of the filling tube 4202 has a distal port
4206 and a plurality of side ports 4204 for delivering the
hardenable medium to the filling structure. Additionally, the
distal end of the filling tube 4202 has a tapered and rounded tip
which reduces the diameter of the plug once hardened, creating a
break point when the plug is removed. FIG. 43 illustrates
retraction of the filling tube away from the filling structure 4208
after hardening of the filling medium 4210. Because the filling
medium is provided by multiple ports, several smaller plugs 4212
result and because of their smaller size, they easily break away
from the filling material 4210 in the filling structure 4208
without leaving sharp protrusions. The polymer plugs remain inside
the fill tube and break at the ports, instead of leaving a
protruding tail. Additionally, having multiple ports 4204 is
advantageous since the filling structure 4208 could be drawn into
the lumen and block the distal portion 4206 during draining of the
filling structure which can involve the use of a vacuum. The
additional ports 4204 allow filling medium to be removed and/or
delivered even if the distal port 4206 is blocked.
[0137] A double filling tube may be used to avoid some of the
challenges discussed above. In FIG. 45A an outer filling tube 4502
has an inner filling tube 4504 extending along its length. The
distal ends of both filling tube are disposed in the filling
structure 4508. Filling medium 4506 can be delivered to the filling
structure 4508 first, via the inner filling tube 4504. The inner
filling tube may be retracted from both the filling structure 4508
and the outer filling tube 4502 after filling material has been
delivered 4508 as seen in FIG. 45B. The filling structure does not
always completely fill up with filling medium due to a number of
reasons such as viscosity, stagnation around the filling tubes,
etc. More commonly, the filling structure may not be completely
filled up because the physician may not infuse an adequate volume
of filling medium. Thus there may be unfilled regions 4510.
Additional filling medium 4506 may be added to the filling
structure 4506 using the outer filling tube 4502 or a new inner
filling tube may be advanced through the outer filling tube 4502.
This allows the unfilled regions 4510 to be more completely filled
as seen in FIG. 45C.
[0138] The filling tubes may have many geometries. They may be
round, rectangular or other configurations. Generally, it is
preferred that the filling tubes have a low profile in order to
maintain a low delivery diameter of the entire system. For example,
in FIG. 46A the filling tube 4608 has a width greater than its
height. This allows the filling tube to more easily fit in the
annular space between the inner surface of a filling structure or
outer sheath 4610 and the endoframe 4604 which mounted over a
balloon 4606 on a delivery catheter 4602. FIG. 46B illustrates
nesting of an inner filling tube 4614 in an outer filling tube 3612
with an optional wire mandrel or stylet 4616 which may be used to
prevent kinking of the filling tubes. In some embodiments, a
filling tube 4614a may have a separate lumen 4618 for a stiffening
mandrel. FIG. 47A illustrates an exemplary embodiment of a delivery
system where the filling structure 4702 is axially separated from
the endoframe 4712 and a sheath 4704 covers both during delivery.
The endoframe 4712 is mounted over a balloon 4710 coupled to a
catheter shaft 4708. FIG. 47B illustrates a cross section of FIG.
47A taken along the line B-B and highlights the low profile filling
tube 4706 in the annular space between the sheath 4704 and the
endoframe 4712. Once the sheath 4704 is retracted and the endoframe
is advanced into the filling structure 4702, pressure in the
filling tube 4706 will force open the filling tube 4706 and permit
greater fluid flow.
[0139] It can be challenging to maintain an airtight seal between
the filling structure and the removable filling tube. Additionally,
when the filling medium hardens, it can be challenging to separate
the filling tube from the filling structure after in situ curing.
FIGS. 39A-39C illustrate one embodiment that facilitates separation
of the filling tube from the filling structure while maintaining
the required airtight seal. In FIG. 39A a filling tab 3904 is
attached to filling structure 3902. The filling tab 3904 may be the
same material as the filling structure 3902 or a different
material. The filling tab may be welded, bonded, integral with, or
otherwise attached to the filling structure. Filling tab 3904 has a
perforation 3906 in it to allow for easy separation. Filling tube
3908 runs through filling tab 3904. A duck bill valve (not
illustrated) or other one-way valve may also be incorporated into
the fill tab to prevent filling medium leakage. After the filling
structure 3902 has been filled and hardened, filling tube 3908 is
pulled away from the filling structure 3902. The perforation 3906
allows the fill tab to easily tear away from the filling structure
as seen in FIG. 39B and then the fill tube is removed from the
filling structure, leaving only a small portion of filling tab 3904
connected to the filling structure 3902, as illustrated in FIG.
39C. In some situations, it may be advantageous to provide some
slack in the fill tab. For example, when the filling structure is
coupled with the fill tube 3908 using a tether 4006, lockwire 4004,
constrictor knot 4008, tether loop 4010 (such as described above),
the fill tab may be corrugated 4002 or additional material may be
bunched together to allow expansion. The corrugation 4002 provides
some slack in the fill tab 3904 to prevent unwanted detachment of
the fill tube 3904 at the perforation 3906 when the fill tube 3908
is moved relative to the filling structure 3902. Once the lockwire
4004 is removed from the tether 4006, the tether 4006 is de-coupled
from the tether loop 4010 and then the fill tab 3904 may be
separated at the perforation 3906.
[0140] Various modifications of the protocols described above will
be within the scope of the present invention. For example, while
some of the scaffolds have been shown as being delivered at the
same time as deployment of the filling structure(s), it will also
be possible to deliver the scaffolds after deployment of the
filling structures. The scaffolds could be delivered on the same or
different delivery catheter(s) used to deliver and/or shape the
filling structures. The scaffolds could then be expanded before,
during or after filling the filling structure.
[0141] Pressure monitoring can also 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, rupture 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 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 or syringe, to deliver the filling medium. Control
decisions can be made using any one of these pressure measurements
or a combination thereof. U.S. patent application Ser. No.
11/482,503 (Attorney Docket No. 025925-001410US) discloses a number
of pressure measuring embodiments, the entire contents of which are
incorporated herein by reference.
[0142] For example, in FIG. 48A, an endoframe 4802 and filling
structure 4808 are positioned in the aneurysm AAA. After
preliminary expansion of the endoframe 4802 and filling of the
filling structure 4803 with saline or other fluid, contrast media
may be injected into the aneurysm and observed under fluoroscopy.
If a leak is observed 4806 around the filling structure, the
physician may add additional saline or fluid to the filling
structure until the leak is no longer observed as illustrated in
FIG. 48B. The saline may then be removed from the filling
structure. The volume of filling medium and pressure used to obtain
this result are recorded and then used when the filling structure
is filled with the hardenable filling medium. An exemplary
embodiment of a delivery system capable of treating the aneurysm
and providing the contrast media to the aneurysm is illustrated in
FIG. 49. In FIG. 49, a filling structure 4906 having a filling tube
4914 is mounted over an endoframe 4914 which in turn is disposed
over a balloon 4916 coupled with the delivery catheter shaft 4918.
A wire 4910 is coupled with a nosecone 4908 on the distal end of
the delivery catheter 4918. The wire 4910 is used to guide an
angiography catheter, here a single lumen tube 4912 around the
filling structure 4906. During delivery to the aneurysm, the entire
system is housed in a delivery sheath 4902. While disposed in the
sheath, the angiography catheter 4912 is proximal to the filling
structure 4906 in order to keep profile to a minimum. Once near the
device has been advanced to the aneurysm, the sheath 4902 may be
retracted proximally thereby exposing the angiography catheter and
filling structure. The angiography catheter 4912 may be advanced
distally over the wire 4910 so that contrast media may be delivered
upstream of the filling structure or between the aneurysm wall and
the filling structure.
[0143] Similar to the filling tube, the angiography catheter should
also have a low profile but it's lumen should also have as large a
cross-sectional area in order to allow easy, low pressure delivery
of contrast media at very high flow rates, 500-1,000 cc/minute.
FIG. 50A illustrates one possible embodiment for an angiography
catheter. In FIG. 50A, the angiography catheter 5010 has a flat,
crescent shaped profile that lays flat and can fit in the annular
space between the scaffold 5006 and the filling structure 5008. The
scaffold 5006 is carried by a balloon mounted near a distal end of
the delivery catheter 5002. FIG. 50B illustrates another embodiment
where the delivery catheter 5002 includes a guidewire lumen. The
lumen is large enough to accommodate a guidewire GW and still allow
delivery of contrast media. In some embodiments, the distal end of
the catheter 5002 may include a nosecone 5012 having side ports
5014 that allow the contrast media to exit laterally, as well as
the distal port 5016.
[0144] In an exemplary method of deploying a filling structure and
scaffolding, pressure monitoring may be utilized in the following
way. After two filling structures have been delivered to the
treatment site, both scaffolds are radially expanded to help create
a lumen for blood flow through the filling structure across the
aneurysm. Using data from a patient's computerized tomography (CT)
scans, a fill volume of the aneurysm treatment site may be
estimated and then divided by two, half for each of the two filling
structures. This represents the baseline filling volume for each
filling structure and is the minimum volume of filling material to
be injected into each of the filling structures. Syringes or other
injection devices coupled with a pressure gage may be used to
optionally pre-fill each filling structure with contrast material
using the baseline volume and the resulting baseline fill pressure
may be noted. This allows unfurling of the filling structure and
provides a preliminary assessment of how the expanded filling
structures fit into the aneurismal space. Once this is
accomplished, the contrast material is removed from the filling
structures. Again using the patient CT data, a functional fill
volume may be determined. This volume is a percentage of the
aneurysm volume obtained from the CT data, or it may be a
predetermined number and is the volume of filling material that
effectively seals and excludes the aneurysm. Functional fill
pressure will be the pressure at which the functional fill volume
is attained. A polymer fill dispenser may then be used to fill each
filling structure with the functional fill volume and the
functional fill pressure is noted. While holding the functional
fill volume and pressure, the filling structure may be observed
under fluoroscopy to check for proper positioning, filling and the
absence of leakage across the aneurysm. If leaks are observed,
additional polymer may be added to the filling structures until the
leaks are prevented or minimized. Excessive additional polymer
should not be added to the filling structure in order to avoid
exceeding a safe fill volume or safe fill pressure. Once the
physician is satisfied with the filling and positioning of the
filling structures, stopcocks to the filling structures may be
closed to allow the polymer to harden and then the delivery devices
may be removed from the patient.
[0145] FIGS. 13A-13D illustrate an exemplary method of directly
monitoring pressure in the filling structure to help ensure that it
is properly inflated relative to the aneurysm. In FIG. 13A, a
filling structure 475 is placed in the aneurysm A and scaffolding
478 provides support to the lumen created by filling structure 475
so that blood may flow from above the aneurysm into the iliac
arteries IA A syringe 482 containing a filling material such as
polyethylene glycol (PEG) is fluidly coupled to the filling
structure 475 via fluid line 480. Filling pressure may be monitored
in a number of ways including using a pressure gage 484 coupled to
syringe 482, a graphical pressure monitor 486 or a blood pressure
cuff 488. In FIG. 13B, as syringe 482 is actuated, the pressure
will spike and the PEG will be injected into the filling structure
475. A pressure relief valve may be used to eliminate or reduce the
spiking or electronic filtering may be used to remove the unwanted
spike. Due to the viscosity of the PEG, as the polymer is being
injected, the pressure will rise in the syringe 482 as measured by
gage 484 relative to the pressure in the filling structure 475 as
measured by gage 492 and also relative to the blood pressure as
indicated by gage 490. This pressure will rise until high enough to
move the PEG through the fluid line 480 into the filling structure
475 against the pressure of the blood 490. During filling, filling
pressure 484 measured at the syringe 482 by gage 484 is equivalent
to blood pressure measured at gage 490 and within filling structure
492, and this is illustrated in FIG. 13C. As the filling structure
475 fills and begins to expand into engagement with the aneurysm
wall A, filling pressure measured by gage 484 will increase again.
This time syringe pressure will also match pressure in the filling
structure 492, both of which will be greater than the blood
pressure 490, as seen in FIG. 13D.
[0146] In addition to actual pressure monitoring by gages and
graphical displays, etc., other pressure indicators may also be
used to facilitate determining the filling status of the filling
structure. FIGS. 14A-14C show an exemplary embodiment employing a
relief valve. In FIG. 14A, a filling device 502 is used to fill
filling structure 506 via fluid line 504. As filling device 502 is
actuated, fluid will be delivered to the filling structure 506.
Initially, there will be a pressure spike at the filling device 502
end of the system and because of this spike, the higher pressure
drives the fluid filling medium into the filling structure 506. The
pressure spike also makes it challenging to use an over-pressure
relief valve to prevent over pressurizing the filling structure.
However, a relief valve may be located closer to the filling
structure end thereby reducing the potential for unintentional
bleeding of the system due to pressure spikes. In FIG. 14B, a
relief valve 508 is coupled to filling structure 506. The relief
valve is preset to a certain pressure such that beyond the preset
pressure, any additional filling material will bleed out of the
filling structure. While the relief valve may be adjacent the
filling structure, preferably the filling material will be vented
toward the proximal end (handle end) of the catheter, outside the
body. This keeps potentially dangerous fluids or other filling
material from being introduced into the body. In another embodiment
seen in FIG. 14C, when fluid bleeds out of relief valve 508 it
fills a reservoir 512 which may be disposed either in or alongside
catheter shaft 510. As reservoir 512 fills with filling medium, it
is observed under fluoroscopy or other imaging modalities and when
filled, the operator knows to stop filling the filling structure
506.
[0147] While the use of a pressure relief valve such as described
with respect to FIGS. 14A-14C can be advantageous, it also can
present challenges. For example, in FIG. 25A, a pressure relief
valve 804 is placed in between a filling device 802 and the filling
structure 808 with pressure gages 806, 810 positioned to monitor
pressure at the pressure relief valve 804 and at the filling
structure 808. Once the filling device 802 is actuated, pressure in
the system will increase significantly which can trip the relief
valve 804 into venting the excess pressure as seen in FIG. 25B
before the filling structure is pressurized as seen in gage 810.
Thus, it will be very difficult to fill the filling structure 808
since most of the filling material will be vented out of relief
valve 804. FIGS. 26A-26C illustrate a potential solution for this
challenge. In FIG. 26A, a four-way, 3 port stopcock 812 is placed
in between the filling device 802 and the filling structure 808.
Prior to actuating the filling device 802, stopcock 804 is adjusted
so that flow is turned off to the pressure relief valve 804. Then,
filling device 802 may be actuated and stopcock 804 may be adjusted
to turn flow on in all directions. By turning the stopcock 804 off
during actuation of filling device 802, the relief valve will not
be exposed to pressure spikes, thereby preventing unwanted venting.
FIG. 26A shows the stopcock adjusted to turn flow off to the
pressure relief valve 804. FIG. 26B shows actuation of filling
device 802 with the stopcock 812 still adjusted to stop flow to
pressure relief valve 804. FIG. 26C shows stopcock 812 adjusted to
allow flow in all directions. Pressure gages 806, 810 and 814 show
relative pressure at various positions between filling device 802
and filling structure 808.
[0148] Some embodiments do not utilize a pressure relief valve and
therefore other ways of masking the pressure line from pressure
spikes are also desirable. For example, when an electronic pressure
transducer is used, a low pass filter may be used to eliminate the
pressure spike observed during actuation of the filling device.
Additionally, electronic recording devices may be set to calculate
and display the average pressure over a longer period of time (e.g.
sample pressure over 20 seconds rather than 2 seconds), or sampling
frequency may be reduced. This will effectively eliminate the
pressure spike or "mask" it out and the resulting pressure display
is a value that more closely indicates pressure of the filling
structure. An exemplary embodiment of a pressure gage that masks
pressure spikes is illustrated in FIGS. 51A-51B. In FIG. 51A,
pressure measuring device 5104 includes an internal flexible
membrane 5106 such that when high pressure fluid is delivered from
a source such as syringe 5102, the membrane 5106 will compress and
absorb some of the pressure, thereby masking any spikes. Once the
membrane 5106 is pressed against the housing 5108, it cannot deform
any further and thus higher pressures will not be transmitted to
the gage as seen in FIG. 51B. One advantage of this type of
pressure gage is that there are no static areas during
pressurization and thus the hardenable filling medium cannot pool
and obstruct flow.
[0149] FIGS. 15A-15B illustrate still another visual indicator that
may be used to control filling of the filling structure. In FIG.
15A, a filling device 502 is fluidly coupled to filling structure
506 via fluid line 504. A mechanical pressure indicator 514 is
coupled with filling structure 506. The mechanical pressure
indicator 514 has two positions, a first closed position as seen in
FIG. 15A and a second open position see in FIG. 15B. The indicator
springs open from the closed to opened position at a predetermined
pressure value. The indicator is radiopaque and thus may be seen
under fluoroscopy. Thus, when the indicator pops out, the operator
knows that the filling structure 506 has reached a certain pressure
and/or volume.
[0150] Placing a fluid filled balloon tipped catheter in the space
between the filling structure and the aneurysm wall allows the
pressure exerted by the filling structure against the aneurysm wall
to be measured, and this is illustrated in FIGS. 16A-16B. In FIG.
16A, a partially filled, compliant balloon tipped catheter 524 is
placed between an outer wall of filling structure 520 and an inner
wall of the aneurysm A. The balloon catheter 524 may be deployed
separately from or together with the filling structure deployment
catheter. The balloon 524 may be filled with saline, carbon dioxide
or like fluids. The catheter 524 is fluidly coupled with a pressure
monitor such as gage 522 via a fluid line 526. At neutral fill
volumes, the pressure of the blood is transmitted through the
balloon 524, along fluid line 526 to pressure monitoring device
522, here a pressure gage. As the filling structure 520 is filled
with a hardenable material, it will begin to press the balloon 524
against the aneurysm wall, squeezing it and thus exerting a higher
pressure which is transmitted along fluid line 526 to pressure gage
522, as seen in FIG. 16B. Thus, an operator may continue to fill
the filling structure 520 until gage 522 indicates a desired
pressure, thereby demonstrating adequate contact between the
filling structure 520 and aneurysm wall.
[0151] In addition to monitoring pressure of a balloon 524 placed
between the filling structure and the aneurysm wall, other pressure
indicators may be used to determine when to stop filling the
filling structure. FIG. 17A shows how inwardly directed pressures
exerted by an expanding filling structure and an aneurysm wall are
directed against a balloon 546 coupled to pressure gage 544 via
fluid line 542. This is similar to the embodiment previously
discussed in FIGS. 16A-16B. However, in FIGS. 17B-17C, the pressure
gage 544 is substituted with a spring loaded pressure indicator
544. Balloon 546 may be partially filled and preferably has a flat
section that may be placed in the space between an outer wall of a
filling structure and an inner wall of the aneurysm and is
fabricated from a compliant material in order to provide accurate
pressure feedback. As the filling structure expands and begins to
compress the balloon 546 against the aneurysm wall, balloon 546 is
compressed. The pressure transmitted by fluid line 542 to spring
loaded pressure indicator 544 increases. However, the spring
mechanism in indicator 544 resists the force until a predetermined
value is reached. In FIG. 17C, once the predetermined value is
exceeded, the spring collapses and a pin pops out of the indicator
housing, alerting the user that the filling structure has been
filled or that a desired pressure has been obtained. Different
springs may be used in order to adjust the indicator to different
pressure set points. In alternative embodiments, other compression
mechanisms other than springs may be used.
[0152] The balloon 546 and pressure indicator 544 may be integrated
with a filling mechanism or the two may be separate from one
another. FIGS. 18A-18B illustrate a combined filling mechanism with
pressure indicator that serves as a lockout mechanism to prevent
overfilling of the filling structure. In FIG. 18A, a gun-like
filling device 552 comprises a handle 554 for actuating the filling
device 552. As handle 554 is actuated by squeezing, filling
material is discharged from a reservoir through a filling tube into
the filling structure. A rack 556 having teeth is coupled with
handle 554 to provide an operator with tactile feedback so that the
operator knows how far handle 554 has been actuated. A locking
mechanism 560 similar to the pressure indicator described above
with respect to FIGS. 17A-17C is also coupled with filling device
552. In this embodiment, when pressure from fluid line 558 coupled
to the filling structure or a balloon catheter exceeds a
predetermined value, plunger 562 springs out of the locking
mechanism 560 and engages one of the teeth on rack 556, thereby
preventing further actuation of handle 554. Thus, filling mechanism
552 may be used to fill the filling structure but without
overfilling it.
[0153] Instead of a separate balloon catheter placed between the
filling structure and aneurysm wall, the filling structure may
include a separate compartment that acts like the balloon catheter
previously described in FIGS. 16A-16B. FIG. 19A illustrates a
filling structure 576 having a separate compliant compartment 578.
Compartment 578 may be pre-filled with a fluid such as saline or
carbon dioxide. As filling structure 576 is filled and expands into
the aneurysm wall, compartment 578 will be compressed and pressure
therein will increase. Pressure in compartment 578 may be monitored
via fluid line 580 by any number of methods including using a gage,
a display or the like. This embodiment saves the operator from
having to deliver a balloon catheter like that of FIGS. 16A-16B to
the site of the aneurysm. FIG. 19B illustrates a side view of the
embodiment in FIG. 19A.
[0154] FIG. 19C illustrates how the filling structure 576 may
include a compliant balloon-like member 578 for monitoring pressure
between the filling structure and the aneurysm wall. In this
embodiment, the balloon-like member 578 includes upper and lower
arms 582 that circumferentially extend around all or a portion of
the filling structure 576. The arms 582 allow contact between
different parts of the filling structure to be monitored thereby
preventing over inflation in one region and underinflation in
another region. A fluid line 580 allows the balloon-like member 578
to be coupled with a pressure monitoring device. FIG. 19D
illustrates still another embodiment of a filling structure having
multiple separate compartments 584 located at several different
points around filling structure 576. Similar to the embodiment of
FIG. 19C, having multiple compartments allow filling of the filling
structure to be assessed at several locations to ensure uniformity
of filling. Each compartment may monitor pressure independently of
the other compartments or they may be fluidly coupled together.
[0155] The scaffolding itself may also be used to indicate the
filling status of the filling structure. In FIG. 20A, a filling
structure is disposed over scaffold 604. Scaffold 604 has regions
606 which are designed to collapse at a lower radial pressure than
the rest of the scaffold. Thus, when filling structure 602 is
filled, it will exert a force against scaffold 604. The weakened
regions 606 collapse inwardly slightly, without substantially
occluding the lumen for blood flow, thereby forming a series of
peaks and valleys which are visible under fluoroscopy. This is
illustrated in FIG. 20B. An operator may therefore use this to
monitor the extent of filling in the filling structure 602.
[0156] In still another embodiment, the balloon used to radially
expand the scaffolding may also be used to monitor pressure. In
FIG. 21, a delivery catheter 610 comprises an expandable balloon
618 disposed on a distal end of the catheter shaft and a
scaffolding 614 is disposed thereover. Once the filling structure
616 is advanced into the aneurysm it may be filled. Balloon 618 is
partially expanded into engagement with the filling structure 616.
As the filling structure enlarges, it begins to compress the
balloon 614. Catheter 610 transmits the pressure from balloon 616
to a pressure gage 612 so that the operator may monitor filling
pressure. Thus, the operator may stop filling the filling structure
when a predetermined pressure value is obtained. The scaffolding
614 may then be fully expanded either before, during or after
filling the filling structure. The balloon 618 is then deflated and
the delivery catheter 610 is removed from the aneurysm.
[0157] Other embodiments may control filling of the filling
structures by using either a balloon on the delivery catheter or
the filling structures themselves. For example, in FIGS. 27A-27B,
two filling structures 852, 854 are positioned in the aneurysm AAA
and partially filled with a filling device 862 to a predetermined
volume or pressure. Balloons 856, 858 on a delivery catheter are
inflated using an inflation device 860. As the balloons expand, the
partially filled filling structures 852, 854 are pressed against
the aneurysm walls, filling the aneurismal space and excess fluid
is then forced out of the filling structures 852, 854 via a relief
valve 868 seen in FIG. 27B. Scaffolds 864, 866 help maintain the
lumen after the balloons 856, 858 are deflated.
[0158] FIGS. 28A-28B illustrate another embodiment where the
filling structures themselves are used to help control their
filling status. In FIG. 28A, two filling structures 852, 854 are
positioned in the aneurysm AAA. A first filling structure 852 is at
least partially filled. In FIG. 28B, the second filling structure
854 is filled so that it compresses filling structure 852. As
filling structure 852 is compressed, excess fluid is vented from
filling structure 852 via a pressure relief valve 868. This process
is continued until the filling structures are essentially
symmetrical with one another as may be observed under
fluoroscopy.
[0159] While the above is a complete description of the preferred
embodiments of the invention, various alternatives, modifications,
and equivalents may be used. The various features of the
embodiments disclosed herein may be combined or substituted with
one another. Therefore, the above description should not be taken
as limiting in scope of the invention which is defined by the
appended claims.
* * * * *