U.S. patent application number 09/270150 was filed with the patent office on 2001-12-06 for method for containing and removing occlusions in the carotid arteries.
Invention is credited to BAGAOISAN, CELSO J., HA, HUNG V., MUNI, KETAN P., PATEL, MUKUND R., ZADNO-AZIZI, GHOLAM-REZA.
Application Number | 20010049517 09/270150 |
Document ID | / |
Family ID | 23030123 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010049517 |
Kind Code |
A1 |
ZADNO-AZIZI, GHOLAM-REZA ;
et al. |
December 6, 2001 |
METHOD FOR CONTAINING AND REMOVING OCCLUSIONS IN THE CAROTID
ARTERIES
Abstract
A method for the treatment of a stenosis or an occlusion in a
blood vessel is disclosed in which a main catheter is first
delivered to a site proximal to the occlusion. The main catheter
may include an occlusive device at its distal end. An inner
catheter or elongate member (e.g., a guidewire) having an occlusive
device at its distal end is delivered to the site of the occlusion,
and the occlusive device is activated at a site distal to the
occlusion. A therapy catheter is then introduced to treat the
occlusion. Next, a catheter is delivered just proximal to the
occlusive device, and this catheter is used to aspirate and/or
irrigate the area removing particles and debris. The aspiration and
irrigation steps are preferably repeated until the particles and
debris are removed. Perfusion may be performed by using a
perfusion-filter distal of the lesion to be treated or a hypotube
which extends beyond the occlusive device attached to the
guidewire. The present invention provides for a minimally invasive
procedure which can be performed quickly and efficiently, with
reduced risks to the patient.
Inventors: |
ZADNO-AZIZI, GHOLAM-REZA;
(NEWARK, CA) ; PATEL, MUKUND R.; (SAN JOSE,
CA) ; MUNI, KETAN P.; (SAN JOSE, CA) ;
BAGAOISAN, CELSO J.; (UNION CITY, CA) ; HA, HUNG
V.; (SAN JOSE, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR
620 NEW PORT CENTER DR.
16TH FLOOR
NEWPORT BEACH
CA
92660
|
Family ID: |
23030123 |
Appl. No.: |
09/270150 |
Filed: |
March 16, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09270150 |
Mar 16, 1999 |
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08933816 |
Sep 19, 1997 |
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08933816 |
Sep 19, 1997 |
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08813810 |
Mar 6, 1997 |
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Current U.S.
Class: |
604/509 ;
604/96.01 |
Current CPC
Class: |
A61M 25/0071 20130101;
A61B 2217/005 20130101; A61M 2025/0081 20130101; A61B 17/22
20130101; A61M 25/008 20130101; A61M 2025/1052 20130101; A61M
25/1011 20130101; A61M 2210/0693 20130101; A61B 2017/22067
20130101; A61M 2025/0183 20130101; A61B 2017/22084 20130101 |
Class at
Publication: |
604/509 ;
604/96.01 |
International
Class: |
A61M 031/00 |
Claims
What is claimed is:
1. A method for the treatment of an occlusion in a branch of a
bifurcated blood vessel having a common portion and two branches,
such as the carotid artery, comprising: providing an elongate
member having an occlusive device at a distal end portion thereof;
delivering the elongate member through the common portion of the
bifurcated vessel and into a branch of the bifurcated vessel, such
as the internal carotid artery; positioning the occlusive device in
said branch distal of the occlusion; sliding a therapy catheter on
the elongate member; occluding said branch only on the distal side
of the occlusion by actuating the occlusive device; treating the
occlusion with the therapy catheter; providing a second catheter
having a fluid flow lumen in fluid communication with a fluid flow
opening at a distal end portion of the second catheter; using the
occlusive device to occlude said branch of the vessel while: (a)
positioning the fluid flow opening of the second catheter in said
branch of the vessel at a location between the occlusive device and
the treated occlusion; (b) applying fluid pressure to the fluid
flow lumen to cause fluid flow along said branch, between (i) an
intersection of said branch with the common portion and (ii) said
location, whereby fluid flows across the treated occlusion; and
deactuating the occlusive device.
2. The method of claim 1, comprising removing the therapy catheter
from said branch of the vessel prior to applying the fluid
pressure.
3. The method of claim 1, wherein the fluid flow across the treated
occlusion flushes emboli in said branch away from the treated
occlusion.
4. The method of claim 1, wherein said applying fluid pressure
comprises aspirating fluid into the lumen to draw emboli away from
the treated occlusion and into the lumen.
5. The method of claim 4, wherein fluid is aspirated at a rate
between 0.5 and 5 cc/sec.
6. The method of claim 4, wherein fluid is aspirated at a rate of
between 0.5 to 1.1 cc/sec.
7. The method of claim 1, wherein said applying fluid pressure
comprises irrigating through the second catheter.
8. The method of claim 7, wherein said method further comprises
ejecting sufficient irrigation fluid from the second catheter to
transport emboli from the treated occlusion along said branch to
the intersection, whereby the emboli are flushed down another
branch of the bifurcated vessel.
9. The method of claim 8, wherein the irrigation fluid has a flow
rate of between 0.1 and 5 cc/sec.
10. The method of claim 8, wherein the irrigation fluid has a flow
rate of between 0.5 and 2 cc/sec.
11. The method of claim 1, wherein the second catheter is an
intermediate catheter.
12. The method of claim 1, comprising allowing blood to flow from
the common portion of the bifurcated vessel through another branch
of the vessel during said using of the occlusive device to occlude
said branch.
13. The method of claim 1, comprising applying the fluid pressure
to the fluid flow lumen in the form of pulses.
14. The method of claim 1, wherein said providing the elongate
member comprises providing a distal elongate member portion that is
more flexible than a proximal elongate member portion.
15. The method of claim 1, wherein said applying fluid pressure
comprises first aspirating and then irrigating.
16. The method of claim 1, comprising: positioning an outer
catheter such that a portion of the outer catheter is in the common
portion of the vessel, the outer catheter having a radial extent
that permits the therapy catheter and the second catheter to pass
through the outer catheter; and irrigating through the second
catheter while simultaneously aspirating through the outer
catheter.
17. The method of claim 16, wherein a fluid flow opening of the
outer catheter is positioned proximal to the treated lesion.
18. The method of claim 1, wherein the blood vessel is the carotid
artery.
19. The method of claim 1, wherein said treating the occlusion
comprises balloon angioplasty or deploying a stent.
20. The method of claim 1, wherein said actuating the occlusive
device comprises inflating an occlusion balloon.
21. The method of claim 20, wherein the balloon is of a compliant
material.
22. The method of claim 1, wherein the elongate member is a tubular
metallic guidewire.
23. A method for the treatment of an occlusion in a branch of a
bifurcated blood vessel having a common portion and two branches,
such as the carotid artery, comprising: providing an elongate
member having an occlusive device at a distal end portion thereof;
delivering the elongate member through the common portion of the
bifurcated vessel and into a branch of the bifurcated vessel, such
as the internal carotid artery; positioning the occlusive device in
said branch distal of the occlusion; sliding a therapy catheter on
the elongate member; occluding said branch on the distal side of
the occlusion by actuating the occlusive device; treating the
occlusion with the therapy catheter; removing the therapy catheter
from said branch of the vessel; providing a second catheter having
a fluid flow lumen in fluid communication with a fluid flow opening
at a distal end portion of the second catheter; sliding the second
catheter on the elongate member after said removal of the therapy
catheter; using the occlusive device to occlude said branch of the
vessel while: (a) positioning the fluid flow opening of the second
catheter in said branch of the vessel at a location between the
occlusive device and the treated occlusion; (b) applying fluid
pressure to the fluid flow lumen to cause fluid flow along said
branch, between (i) an intersection of said branch with the common
portion and (ii) said location, whereby fluid flows across the
treated occlusion; and deactuating the occlusive device.
24. The method of claim 23, wherein said applying fluid pressure
comprises aspirating fluid into the lumen to draw emboli away from
the treated occlusion and into the lumen.
25. The method of claim 24, wherein fluid is aspirated at a rate
between 0.5 and 5 cc/sec.
26. The method of claim 24, wherein fluid is aspirated at a rate of
between 0.5 to 1.1 cc/sec.
27. The method of claim 23, wherein said applying fluid pressure
comprises irrigating through the second catheter.
28. The method of claim 27, wherein said method further comprises
ejecting sufficient irrigation fluid from the second catheter to
transport emboli from the treated occlusion along said branch to
the intersection, whereby the emboli are flushed down another
branch of the bifurcated vessel.
29. The method of claim 28, wherein the irrigation fluid has a flow
rate of between 0.1 and 5 cc/sec.
30. The method of claim 28, wherein the irrigation fluid has a flow
rate of between 0.5 and 2 cc/sec.
31. The method of claim 23, comprising applying the fluid pressure
to the fluid flow lumen in the form of pulses.
32. The method of claim 23, further comprising inflating a balloon
on an outer catheter within the common portion of the vessel to
occlude the common portion.
33. The method of claim 23, wherein the elongate member is a
tubular metallic guidewire.
34. A method for the treatment of an occlusion in a branch of a
bifurcated blood vessel having a common portion and two branches,
such as the carotid artery, comprising: providing an elongate
member having an occlusive device at a distal end portion thereof;
delivering the elongate member through the common portion of the
bifurcated vessel and into a branch of the bifurcated vessel, such
as the internal carotid artery; positioning the occlusive device in
said branch distal of the occlusion; sliding a therapy catheter on
the elongate member; occluding said branch only on the distal side
of the occlusion by actuating the occlusive device; treating the
occlusion with the therapy catheter; using the occlusive device to
occlude the branch of the vessel while: (a) delivering irrigation
fluid to a distal end portion of the therapy catheter through an
annulus between the therapy catheter and the elongate member; (b)
passing the irrigation fluid out of a fluid flow opening in the
distal end portion of the therapy catheter; (c) positioning the
fluid flow opening of the therapy catheter in said branch of the
vessel at a location near the occlusive device between the
occlusive device and the treated occlusion, such that fluid flows
across the treated occlusion; and deactuating the occlusive
device.
35. The method of claim 34, wherein the fluid flow across the
treated occlusion flushes emboli in said branch away from the
treated occlusion.
36. The method of claim 35, further comprising aspirating through
an outer catheter, the outer catheter having a radial extent that
permits the therapy catheter to pass through the outer
catheter.
37. The method of claim 34, wherein the blood vessel is the carotid
artery.
38. The method of claim 34, wherein said treating the occlusion
comprises balloon angioplasty or deploying a stent.
39. The method of claim 34, wherein said treating the occlusion
comprises breaking up the occlusion, such as atherectomy.
40. The method of claim 34, wherein said actuating the occlusive
device comprises inflating an occlusion balloon.
41. The method of claim 34, wherein the elongate member is a
tubular metallic guidewire.
42. A method for the treatment of an occlusion in a branch of
bifurcated blood vessel having a common portion and two branches,
such as the carotid artery, comprising: providing an elongate
member having an occlusive device at a distal end portion thereof;
delivering the elongate member through the common portion of the
bifurcated vessel and into a branch of the bifurcated vessel, such
as the internal carotid artery; positioning the occlusive device in
said branch distal of the occlusion; positioning an outer catheter
so that a portion of the outer catheter is in the common portion of
the vessel; sliding a therapy catheter within the outer catheter
and on the elongate member; actuating the occlusive device such
that it occludes said branch of the vessel; treating the occlusion
with the therapy catheter; using the occlusive device to occlude
the branch of the vessel while: (a) delivering irrigation fluid to
a distal end portion of the outer catheter; (b) passing the
irrigation fluid out of a fluid flow opening in the distal end
portion of the outer catheter; (c) positioning the fluid flow
opening of the outer catheter in said branch of the vessel at a
location between the occlusive device and the treated occlusion,
such that fluid flows across the treated occlusion; and deactuating
the occlusive device.
43. The method of claim 42, wherein the fluid flow across the
treated occlusion flushes emboli in said branch away from the
treated occlusion.
44. The method of claim 43, further comprising: sliding an
additional catheter on the elongate member, the additional catheter
having a fluid flow opening; positioning the fluid flow opening of
the additional catheter between the occlusion and the occlusive
device; and aspirating through the fluid flow opening of the
additional catheter.
45. The method of claim 44, wherein said aspirating is performed
before said delivering irrigation fluid.
46. The method of claim 43, wherein the blood vessel is the carotid
artery.
47. The method of claim 42, wherein said treating the occlusion
comprises breaking up the occlusion, such as atherectomy.
48. The method of claim 42, wherein said treating the occlusion
comprises balloon angioplasty.
49. The method of claim 42, wherein said actuating the occlusive
device comprises inflating an occlusion balloon.
50. The method of claim 42, wherein the outer catheter is a main
catheter.
51. The method of claim 42, wherein the elongate member comprises a
tubular metallic guidewire.
52. A method for treatment of an occlusion in a branch of a
bifurcated blood vessel having a common portion and two branches,
comprising: positioning an occlusive device distal of the occlusion
to occlude said branch of the vessel; treating the occlusion using
a therapy device; delivering irrigation fluid between the occlusion
and the occlusive device such that irrigation fluid flows across
the treated occlusion towards an intersection of said branch and
the common portion, wherein emboli in said branch are carried to
the intersection; allowing anatomical blood flow in the common
portion to carry the emboli through another of the branches.
53. The method of claim 52, additionally comprising using a
catheter to aspirate at a location between the occlusion and the
occlusive device to draw emboli away from the treated occlusion and
into the catheter.
54. The method of claim 52, wherein aspiration is performed before
irrigation.
55. The method of claim 52, wherein the blood vessel is the carotid
artery.
56. The method of claim 52, wherein said treating the occlusion
comprises balloon angioplasty.
57. The method of claim 52, wherein said treating the occlusion
comprises breaking up the occlusion, such as atherectomy.
58. The method of claim 52, wherein said occluding of said branch
comprises inflating an occlusion balloon.
59. A method for the treatment of an occlusion in a blood vessel,
such as the carotid artery, comprising: providing an inner catheter
comprising an elongate member having an occlusive device at a
distal end portion thereof; delivering the elongate member through
the vessel; positioning the occlusive device distal of the
occlusion; sliding a therapy catheter on the elongate member;
actuating the occlusive device such that it occludes the vessel;
treating the occlusion with the therapy catheter; using the
occlusive device to occlude the vessel while: (a) delivering
irrigation fluid through the elongate member; (b) passing the
irrigation fluid out of a fluid flow opening in the occlusive
device such that fluid flows across the treated occlusion; and
deactuating the occlusive device.
60. The method of claim 59, wherein emboli are flushed away from
the treated occlusion.
61. The method of claim 60, wherein the occlusive device comprises
a balloon and the fluid flow opening comprises at least one opening
in the balloon.
62. The method of claim 61, wherein the at least one opening in the
balloon comprises micropores in the balloon material.
63. The method of claim 60, wherein the blood vessel is the carotid
artery.
64. The method of claim 59, wherein said treating the occlusion
comprises balloon angioplasty.
65. The method of claim 59, wherein said treating the occlusion
comprises breaking up the occlusion, such as atherectomy.
66. The method of claim 59, wherein said actuating the occlusive
device comprises inflating an occlusion balloon of a compliant
material.
67. The method of claim 59, wherein the elongate member is a
tubular metallic guidewire.
68. A method of performing a medical procedure in a blood vessel
using an expandable member which seals against walls of the blood
vessel in response to application of an expansion force through a
range of vessel diameters up to a maximum diameter beyond which
sealing will not occur in the vessel, said method comprising:
positioning the expandable member in a selected blood vessel distal
to an occlusion to be treated at a location where the vessel
diameter is at least 20% less than said maximum diameter; applying
an expansion force to cause the expandable member to expand into
sealing contact with walls of the selected vessel at said location;
and treating the occlusion while the expandable member is expanded,
whereby the expandable member seals against walls of the selected
vessel even if the diameter of the selected vessel at said location
increases to said maximum diameter as a result of said
treatment.
69. The method of claim 68, wherein said expandable member includes
a balloon.
70. The method of claim 69, wherein the balloon expands axially as
the expansion force is applied to store potential energy for
expanding the balloon radially if the diameter of the selected
vessel at said location increases.
71. The method of claim 68, in which the blood vessel is the
internal carotid artery.
72. A method of treating an occlusion in a blood vessel,
comprising: positioning an expandable member distal to the
occlusion to be treated; performing therapy on the occlusion; using
the expandable member to block migration of emboli created as a
result of the therapy, while allowing blood to flow from one side
to another side of the expandable member in a proximal to distal
direction; positioning a fluid port of a catheter between the
treated occlusion and the expandable member; and applying suction
to the fluid port to aspirate fluid into the catheter while the
fluid port is positioned between the treated occlusion and the
expandable member.
73. The method of claim 72, comprising injecting irrigation fluid
distal to the treated occlusion to create a flow of fluid across
the treated occlusion in a distal to proximal direction.
74. The method of claim 73, wherein the catheter comprises an
aspiration catheter having an occlusive device near its distal end,
said method comprising using the occlusive device to at least
substantially block anatomical blood flow through the vessel during
said aspiration.
75. The method of claim 74, wherein said injecting comprises
advancing a distal opening in an outer catheter to a location
adjacent a proximal side of the occlusive device and irrigating
through the distal opening of the outer catheter while anatomical
blood flow in the vessel is substantially blocked to cause fluid to
flow across the treated occlusion in a distal to proximal
direction.
76. The method of claim 73, wherein the catheter comprises an outer
catheter having an occlusive device near its distal end, wherein
said method comprises positioning the occlusive device at a
location distal to the treated occlusion, wherein said aspiration
is performed by aspirating through an opening in the outer catheter
that is distal to said location, and wherein said injecting
comprises irrigating through an opening in the outer catheter that
is proximal to said location to cause a flow of fluid across the
treated lesion in a distal to proximal direction.
77. The method of claim 72, wherein the treated occlusion is in a
branch of a bifurcated vessel such as the carotid artery.
78. The method of claim 77, comprising injecting irrigation fluid
into the branch at a location distal to the treated occlusion and
creating a fluid flow across the treated occlusion and to a
junction of the branch with a common portion of the bifurcated
vessel, whereby the irrigation fluid from said branch is flushed
down another branch by anatomical blood flow.
79. The method of claim 72, wherein the aspirated fluid contains
emboli.
80. The method of claim 72, wherein the expandable member comprises
a filter.
81. The method of claim 72, wherein blood flows through the
expandable member.
82. The method of claim 72, wherein said providing fluid flow
comprises providing fluid flow from said another side to said one
side of the expandable member in a distal to proximal direction
during the aspiration of said fluid.
83. The method of claim 72, comprising perfusing blood through a
tube which carries blood from one side of the tube to the
other.
84. A method of treating an occlusion in a blood vessel,
comprising: positioning an expandable member distal to the
occlusion to be treated; performing therapy on the occlusion; using
the expandable member to block migration of emboli created as a
result of the therapy, while allowing blood to flow past the
expandable member in a proximal to distal direction; positioning a
fluid port of a catheter between the treated occlusion and the
expandable member; delivering irrigation fluid through the fluid
port; and using the irrigation fluid to provide fluid flow across
the treated occlusion in a distal to proximal direction.
85. The method of claim 84, wherein the expandable member comprises
an occlusion balloon.
86. The method of claim 85, wherein the catheter comprises an outer
catheter.
87. The method of claim 86, comprising perfusing blood through a
tube which carries blood from one side of the balloon to the
other.
88. The method of claim 84, wherein the treated occlusion is in a
branch of a bifurcated vessel such as the carotid artery.
89. The method of claim 88, wherein said delivering comprises
delivering irrigation fluid into the branch at a location distal to
the treated occlusion and creating a fluid flow across the treated
occlusion and to a junction of the branch with a common portion of
the bifurcated vessel, whereby the irrigation fluid from said
branch is flushed down another branch by anatomical blood flow.
90. A method of treating an occlusion in a blood vessel,
comprising: positioning an expandable member distal to the
occlusion to be treated; using a therapy balloon to perform therapy
on the occlusion; using the expandable member to block migration of
emboli created as a result of the therapy, while allowing blood to
flow from one side to another side of the expandable member in a
proximal to distal direction; using the therapy balloon to occlude
the blood vessel at a location distal to the treated occlusion;
positioning a fluid port of a catheter between the treated
occlusion and said location; and providing fluid flow through the
fluid port such that said fluid flows across the treated
occlusion.
91. The method of claim 90, comprising injecting irrigation fluid
through the fluid port to create a flow of fluid across the treated
occlusion in a distal to proximal direction.
92. The method of claim 90, comprising aspirating through the fluid
port to create a flow of fluid across the treated occlusion in a
proximal to distal direction.
93. The method of claim 90, wherein the treated occlusion is in a
branch of a bifurcated vessel such as the carotid artery.
94. The method of claim 93, comprising injecting irrigation fluid
into the branch at a location distal to the treated occlusion and
creating a fluid flow across the treated occlusion and to a
junction of the branch with a common portion of the bifurcated
vessel, whereby the irrigation fluid from said branch is flushed
down another branch by anatomical blood flow.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 08/933,816 filed Sep. 19, 1997, which is a
continuation-in-part of U.S. patent application Ser. No.
08/813,810, filed Mar. 6, 1997.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to containment and removal of
substances including emboli (such as from thrombi, plaque, and
other types of material and debris) from blood vessels. The
preferred embodiments are particularly advantages for use in the
carotid arteries and other arteries above the aortic arch during
diagnostic and therapeutic procedures.
[0004] 2. Description of the Related Art
[0005] Human blood vessels often become occluded or completely
blocked by plaque, thrombi, deposits, or other substances, which
reduce the blood carrying capacity of the vessel. Should the
blockage occur at a critical place in the circulatory system,
serious and permanent injury, or even death, can occur. To prevent
this, some form of medical intervention is usually performed when
significant occlusion is detected.
[0006] The carotid arteries are the main vessels which supply blood
to the brain and face. The common carotid artery leads upwards from
the aortic arch, branching into the internal carotid artery which
feeds the brain, and the external carotid artery which feeds the
head and face. The carotid arteries are first narrowed and may
eventually be almost completely blocked by plaque, and may further
be complicated by the formation of thrombi (blood clots) on the
roughened surfaces of the plaques. Narrowing or blockage of the
carotid arteries is often untreatable and can result in devastating
physical and cognitive debilitation, and even death.
[0007] Various types of intervention techniques have been developed
which facilitate the reduction or removal of the blockage in the
blood vessel, allowing increased blood flow through the vessel. One
technique for treating stenosis or occlusion of a blood vessel is
percutaneous balloon angioplasty. A balloon catheter is threaded
through the patient's arterial system and inserted into the
narrowed or blocked area, and the balloon is inflated to expand the
constricted area. The fear of dislodging an embolus from an
ulcerative plaque and the severe resulting consequences, however,
has prevented the widespread use of angioplasty in the carotid
arteries. Because of the potential complications, the options for
minimally invasive treatment of the carotid arteries are severely
limited.
[0008] Carotid endarterectomy is another type of intervention for
removal of blockages from the carotid arteries. In endarterectomy,
the carotid bifurcation is exposed through an incision in the neck
of the patient. Clamps are placed on either side of the occlusion
to isolate it, and an incision made to open the artery. The
occlusion is removed, the isolated area irrigated and aspirated,
and the artery sutured closed. The clamps are removed to
reestablish blood flow through the artery. In carotid
endarterectomy, the emboli and debris are contained and directed by
activating and deactivating the clamps. For example, after the
clamps are in place, one on the common carotid artery and one on
the internal carotid artery, the particles are contained between
the two clamps. After the occlusion is removed, the clamp on the
common carotid artery is opened, allowing blood to flow into the
previously isolated area toward the clamp on the internal carotid.
This blood flow is then aspirated through an external aspiration
tube. The common carotid artery is then reclamped, and the clamp on
the internal carotid opened. This causes blood to flow into the
previously isolated area toward the clamp on the common carotid
artery. The flow is then aspirated. The clamp on the internal
carotid artery is closed, and the artery is sutured closed. This
method allows for the flushing of debris into the area where
aspiration occurs.
[0009] Alternatively, this method of clamping and unclamping the
carotid arteries can be done after the incision in the artery is
sutured closed. Using this method, it is hoped that any particles
in the internal carotid artery will be forced back to the common
carotid artery, then into the external carotid area, where serious
complications are unlikely to arise from emboli.
[0010] Carotid endarterectomy is not without the serious risk of
embolization and stroke caused by particles of the blocking
material and other debris moving downstream to the brain, however.
There is therefore a need for improved methods of treatment for
occluded carotid arteries which decrease the risks to the
patient.
SUMMARY OF THE INVENTION
[0011] The present invention provides a novel method for containing
and removing substances such as emboli from blood vessels. The
method is particularly useful in bifurcated vessels, such as the
carotid arteries and in other blood vessels above the aortic arch.
In one embodiment of the method, there is provided at least one
occlusive device such as a balloon or filter, a therapy catheter to
treat the occlusion, and a source of aspiration to remove the
debris created by the therapy. By utilizing the fluid pressure and
flow within the blood vessel, this method can eliminate the need
for a separate irrigation catheter and irrigation fluid.
Alternatively, irrigation fluid may be provided to flush the area.
The minimally invasive treatment allows occlusions to be treated
more rapidly and less invasively than known methods, with reduced
cost and risk to the patient.
[0012] In accordance with one aspect of the present invention,
there is provided a method for the treatment of an occlusion in a
carotid artery. A main catheter having a first occlusive device on
its distal end is inserted into the artery, until the occlusive
device is proximal to the occlusion. The first occlusive device is
activated to occlude the artery proximal to the occlusion. An inner
catheter having a second occlusive device on its distal end is
inserted into the artery across the occlusion, until the occlusive
device is distal to the occlusion. The second occlusive device is
then activated to occlude the artery distal to the occlusion and
create a working area surrounding the occlusion. By occlusive
device is meant any device which is capable of preventing at least
some particles or other debris from migrating downstream. Examples
of occlusive devices include inflatable balloons, filters or
braids, or other mechanical devices.
[0013] According to the foregoing aspect of the invention, a
therapy catheter is then inserted into the working area and used to
treat the occlusion. Appropriate treatment can include direct drug
delivery to the site of the occlusion, angioplasty, cutting,
scraping or pulverizing the occlusion, ablating the occlusion using
ultrasound or a laser, deploying a stent within the artery, use of
a thrombectomy or rheolitic device, or other treatments. Following
treatment of the occlusion, the therapy catheter is removed. An
aspiration catheter is then delivered to the working area, and the
first occlusive device is deactivated to allow blood flow into the
working area. Blood flow from collateral vessels prevent the
movement of particles and debris downstream where they could cause
serious complications. The blood flow also acts as irrigation fluid
to create turbulence within the area. Aspiration of the working
area is then performed to removed particles and debris. Aspiration
can occur simultaneously with the deactivating of the first
occlusive device, if desired. Alternatively, either step can be
performed first.
[0014] In another aspect of the method of the present invention,
the occlusive devices are activated and deactivated more than once.
After the first occlusive device is deactivated to allow blood flow
into the area, the occlusive device is reactivated. The second
occlusive device is then deactivated, to allow blood flow in from
the distal end of the working area. The second occlusive device is
reactivated, and these steps can be repeated any number of times
until sufficient irrigation and aspiration of the working area
occurs.
[0015] In yet another aspect of the method, the first inner
catheter with its occlusive device is delivered into one branch of
a bifurcated vessel (such as the carotid artery), while a second
inner catheter having a third occlusive device on its distal end is
delivered into the other branch of the bifurcated vessel to occlude
it. Aspiration then occurs in both branches of the artery to remove
particles and debris.
[0016] In a further aspect of the method, aspiration occurs through
the main catheter, and a separate aspiration catheter is not
required. Following removal of the therapy catheter, and
deactivation of the first occlusive device to allow blood flow into
the working area, aspiration occurs through the distal end of the
main catheter. This eliminates the need to deliver a separate
aspiration catheter, thus saving time which is critical in these
types of procedures.
[0017] If desired, an irrigation catheter can be delivered into the
working area following the removal of the therapy catheter. The
irrigation catheter is used to deliver irrigation fluid to the
working area. Aspiration then occurs through the distal end of the
main catheter. In this case, anatomical irrigation (the use of the
patient's own blood flow for irrigation) as described above, is not
used.
[0018] Yet another aspect of the method may be performed with a
single occlusive device. A main catheter or guide catheter is first
delivered into the carotid artery, with the distal end positioned
just proximal to the occlusion. An inner catheter having an
occlusive device on its distal end is then positioned with the
occlusive device distal to the occlusion. The occlusive device is
activated to occlude the artery distal to the occlusion. A therapy
catheter is delivered into the artery until it reaches the
occlusion and therapy is performed to reduce or eliminate the
occlusion. The therapy catheter is removed, and an intermediate
catheter is delivered to a position proximal to the occlusive
device. Preferably, the distance between the proximal end of the
occlusive device and the distal end of the intermediate catheter is
narrowed at one point during aspiration to a distance of about 2
centimeters or less. The area just proximal to the occlusive device
is aspirated, using the intermediate catheter, and then irrigated.
The aspirating and irrigating steps can be repeated as often as
necessary to facilitate the removal of particles and debris.
[0019] In another embodiment, the intermediate catheter has two or
more lumens, such that aspiration and irrigation occur through
different lumens within the same catheter. This prevents the
possibility that aspirated particles will be flushed back into the
patient when irrigation is begun.
[0020] In further aspects of the present invention, two and even
three occlusive devices are employed. In the case of two occlusive
devices, a main or guide catheter with an occlusive device on its
distal end is delivered to the common carotid artery and the
occlusive device is activated. Next, an inner catheter with an
occlusive device is delivered distal to the occlusion in the
internal carotid artery and activated, thus isolating the occlusion
between the two occlusive devices. Therapy is performed on the
occlusion, followed by aspiration, and irrigation if desired.
[0021] When three occlusive devices are used, an occlusive device
is activated in the common carotid artery. An inner catheter with
an occlusive device is then delivered to the external carotid
artery and the occlusive device activated. Next, a second inner
catheter is delivered to the internal carotid artery past the site
of the occlusion and the occlusive device activated to occlude the
internal carotid artery. Alternatively, the first inner catheter
and occlusive device is delivered to the internal carotid artery
and activated, followed by delivery and activation of the second
inner catheter and occlusive device in the external carotid artery.
In either case, the occlusion is completely isolated between the
three occlusive devices. This is followed by therapy on the
occlusion and sequential aspiration and irrigation as desired.
[0022] Accordingly, a carotid artery can be treated quickly and
efficiently. The patient's own blood can serve as irrigation fluid,
thereby eliminating the need for a separate irrigation catheter and
supply of irrigation fluid. The working area may be cleaned in an
efficient manner by performing repeated activation and deactivation
of the occlusive devices surrounding the working area. The
catheter-based approach reduces the amount of time required to
complete the procedure, and allows normal blood flow in the vessel
to be restored in a very short period of time. Use of a minimally
invasive procedure reduces risks and trauma to the patient,
decreases costs, and improves recovery time.
[0023] Another aspect of the invention comprises a method for the
treatment of an occlusion in a branch of a bifurcated blood vessel
having a common portion and two branches, such as the carotid
artery, comprising providing an elongate member having an occlusive
device at a distal end portion thereof, delivering the elongate
member through the common portion of the bifurcated vessel and into
a branch of the bifurcated vessel (such as the internal carotid
artery), and positioning the occlusive device in said branch distal
of the occlusion. The method further comprises sliding a therapy
catheter on the elongate member, occluding said branch only on the
distal side of the occlusion by actuating the occlusive device,
treating the occlusion with the therapy catheter, and providing a
second catheter having a fluid flow lumen in fluid communication
with a fluid flow opening at a distal end portion of the second
catheter. The method additionally comprises using the occlusive
device to occlude said branch of the vessel while: (a) positioning
the fluid flow opening of the second catheter in said branch of the
vessel at a location between the occlusive device and the treated
occlusion; and (b) applying fluid pressure to the fluid flow lumen
to cause fluid flow along said branch, between (i) an intersection
of said branch with the common portion and (ii) said location,
whereby fluid flows across the treated occlusion; and then
deactuating the occlusive device.
[0024] Still another aspect of the invention comprises a method for
the treatment of an occlusion in a branch of a bifurcated blood
vessel having a common portion and two branches, such as the
carotid artery, comprising providing an elongate member having an
occlusive device at a distal end portion thereof, delivering the
elongate member through the common portion of the bifurcated vessel
and into a branch of the bifurcated vessel (such as the internal
carotid artery), positioning the occlusive device in said branch
distal of the occlusion, sliding a therapy catheter on the elongate
member, and occluding said branch on the distal side of the
occlusion by actuating the occlusive device. The method further
comprises treating the occlusion with the therapy catheter,
removing the therapy catheter from said branch of the vessel,
providing a second catheter having a fluid flow lumen in fluid
communication with a fluid flow opening at a distal end portion of
the second catheter, and sliding the second catheter on the
elongate member after the removal of the therapy catheter. The
method additionally comprises using the occlusive device to occlude
said branch of the vessel while (a) positioning the fluid flow
opening of the second catheter in said branch of the vessel at a
location between the occlusive device and the treated occlusion;
(b) applying fluid pressure to the fluid flow lumen to cause fluid
flow along said branch, between (i) an intersection of said branch
with the common portion and (ii) said location, whereby fluid flows
across the treated occlusion; and then deactuating the occlusive
device.
[0025] Yet another aspect of the invention comprises a method for
the treatment of an occlusion in a branch of a bifurcated blood
vessel having a common portion and two branches, such as the
carotid artery, comprising providing an elongate member having an
occlusive device at a distal end portion thereof, delivering the
elongate member through the common portion of the bifurcated vessel
and into a branch of the bifurcated vessel (such as the internal
carotid artery), positioning the occlusive device in said branch
distal of the occlusion, sliding a therapy catheter on the elongate
member, occluding said branch only on the distal side of the
occlusion by actuating the occlusive device, and treating the
occlusion with the therapy catheter. The method further comprises
using the occlusive device to occlude the branch of the vessel
while: (a) delivering irrigation fluid to a distal end portion of
the therapy catheter through an annulus between the therapy
catheter and the elongate member; (b) passing the irrigation fluid
out of a fluid flow opening in the distal end portion of the
therapy catheter; and (c) positioning the fluid flow opening of the
therapy catheter in said branch of the vessel at a location near
the occlusive device between the occlusive device and the treated
occlusion, such that fluid flows across the treated occlusion; and
then deactuating the occlusive device.
[0026] Still another aspect of the invention comprises a method for
the treatment of an occlusion in a branch of bifurcated blood
vessel having a common portion and two branches, such as the
carotid artery, comprising providing an elongate member having an
occlusive device at a distal end portion thereof, delivering the
elongate member through the common portion of the bifurcated vessel
and into a branch of the bifurcated vessel (such as the internal
carotid artery), positioning the occlusive device in said branch
distal of the occlusion, positioning an outer catheter so that a
portion of the outer catheter is in the common portion of the
vessel, sliding a therapy catheter within the outer catheter and on
the elongate member, actuating the occlusive device such that it
occludes said branch of the vessel, and treating the occlusion with
the therapy catheter. The method further comprises using the
occlusive device to occlude the branch of the vessel while (a)
delivering irrigation fluid to a distal end portion of the outer
catheter; (b) passing the irrigation fluid out of a fluid flow
opening in the distal end portion of the outer catheter; (c)
positioning the fluid flow opening of the outer catheter in said
branch of the vessel at a location between the occlusive device and
the treated occlusion, such that fluid flows across the treated
occlusion; and then deactuating the occlusive device.
[0027] Still another aspect of the invention comprises a method for
treatment of an occlusion in a branch of a bifurcated blood vessel
having a common portion and two branches, comprising positioning an
occlusive device distal of the occlusion to occlude said branch of
the vessel, treating the occlusion using a therapy device,
delivering irrigation fluid between the occlusion and the occlusive
device such that irrigation fluid flows across the treated
occlusion towards an intersection of said branch and the common
portion, wherein emboli in said branch are carried to the
intersection, and allowing anatomical blood flow in the common
portion to carry the emboli through another of the branches.
[0028] Yet another aspect of the invention comprises a method for
the treatment of an occlusion in a blood vessel, such as the
carotid artery, comprising providing an inner catheter comprising
an elongate member having an occlusive device at a distal end
portion thereof, delivering the elongate member through the vessel,
positioning the occlusive device distal of the occlusion, sliding a
therapy catheter on the elongate member, actuating the occlusive
device such that it occludes the vessel, and treating the occlusion
with the therapy catheter. The method further comprises uses the
occlusive device to occlude the vessel while: (a) delivering
irrigation fluid through the elongate member; (b) passing the
irrigation fluid out of a fluid flow opening in the occlusive
device such that fluid flows across the treated occlusion; and then
deactuating the occlusive device. Still another aspect of the
invention comprises a method of performing a medical procedure in a
blood vessel using an expandable member which seals against walls
of the blood vessel in response to application of an expansion
force through a range of vessel diameters up to a maximum diameter
beyond which sealing will not occur in the vessel, in which the
method comprises positioning the expandable member in a selected
blood vessel distal to an occlusion to be treated at a location
where the vessel diameter is at least 20% less than said maximum
diameter, applying an expansion force to cause the expandable
member to expand into sealing contact with walls of the selected
vessel at said location, and treating the occlusion while the
expandable member is expanded, whereby the expandable member seals
against walls of the selected vessel even if the diameter of the
selected vessel at said location increases to said maximum diameter
as a result of the treatment.
[0029] Another aspect of the invention comprises a method of
treating an occlusion in a blood vessel, comprising positioning an
expandable member distal to the occlusion to be treated, performing
therapy on the occlusion, and using the expandable member to block
migration of emboli created as a result of the therapy, while
allowing blood to flow from one side to another side of the
expandable member in a proximal to distal direction. The method
further comprises positioning a fluid port of a catheter between
the treated occlusion and the expandable member, and applying
suction to the fluid port to aspirate fluid into the catheter while
the fluid port is positioned between the treated occlusion and the
expandable member.
[0030] Still another aspect of the invention comprises a method of
treating an occlusion in a blood vessel, comprising positioning an
expandable member distal to the occlusion to be treated, performing
therapy on the occlusion, and using the expandable member to block
migration of emboli created as a result of the therapy, while
allowing blood to flow past the expandable member in a proximal to
distal direction. The method further comprises positioning a fluid
port of a catheter between the treated occlusion and the expandable
member, delivering irrigation fluid through the fluid port, and
using the irrigation fluid to provide fluid flow across the treated
occlusion in a distal to proximal direction.
[0031] Yet another aspect of the invention comprises a method of
treating an occlusion in a blood vessel, comprising positioning an
expandable member distal to the occlusion to be treated, using a
therapy balloon to perform therapy on the occlusion, using the
expandable member to block migration of emboli created as a result
of the therapy, while allowing blood to flow from one side to
another side of the expandable member in a proximal to distal
direction. The method further comprises using the therapy balloon
to occlude the blood vessel at a location distal to the treated
occlusion, positioning a fluid port of a catheter between the
treated occlusion and said location, and providing fluid flow
through the fluid port such that said fluid flows across the
treated occlusion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a perspective drawing of the carotid arteries.
[0033] FIG. 2 is a side view of an embodiment of a main
catheter.
[0034] FIG. 3 is a cross-sectional view of the main catheter taken
along line 3-3 of FIG. 2.
[0035] FIG. 4 is a cross-sectional view of the main catheter taken
along line 4-4 of FIG. 2.
[0036] FIG. 5 is a side view of the distal end of an embodiment of
an inner catheter.
[0037] FIG. 6 is a partial cross-sectional view of the inner
catheter taken along line 6-6 of FIG. 5.
[0038] FIG. 7 is a side view of an embodiment of an over-the-wire
aspiration catheter.
[0039] FIG. 8 is a cross-sectional view of the over-the-wire
aspiration catheter taken along line 8-8 in FIG. 7.
[0040] FIG. 9 is a cross-sectional view of the over-the-wire
aspiration catheter taken along line 8-8 in FIG. 7, showing an
elongate member (e.g., a guidewire) inserted therethrough.
[0041] FIG. 10 is a side view of an embodiment of a single operator
aspiration catheter.
[0042] FIG. 11 is a cross-sectional view of the single operator
aspiration catheter taken along line 11-11 in FIG. 10.
[0043] FIG. 12 is a side view of an embodiment of an over-the-wire
irrigation or aspiration catheter.
[0044] FIG. 13 is a side view of an embodiment of a single operator
irrigation catheter.
[0045] FIGS. 14 through 16A are cross-sectional views of the single
operator irrigation catheter taken along lines 14-14, 15-15 and
16A-16A of FIG. 13.
[0046] FIG. 17 is a perspective view of one example of an emboli
containment and removal method within a carotid artery.
[0047] FIG. 18 is a perspective view of another example of an
emboli containment and removal method.
[0048] FIG. 19 is a perspective view of yet another example of an
emboli containment and removal method which employs a single
occlusive device.
[0049] FIG. 20 is a perspective view of the emboli containment and
removal method illustrated in FIG. 19, showing the use of an
intermediate catheter.
[0050] FIG. 21 is a perspective view of still another example of an
emboli containment and removal method which employs two occlusive
devices.
[0051] FIG. 22 is a perspective view showing a preferred location
for the intermediate catheter when the intermediate catheter is
used to flush away emboli from the treated occlusion.
[0052] FIG. 23 is a perspective view of an embodiment in which the
intermediate catheter is used for aspiration of emboli.
[0053] FIG. 24 is a perspective view of an embodiment in which the
intermediate catheter is used for irrigation of emboli.
[0054] FIG. 24A is a perspective view of an embodiment in which a
therapy catheter is used for irrigation of emboli.
[0055] FIG. 25 is a perspective view of an embodiment in which the
main catheter is used for aspiration of emboli.
[0056] FIG. 26 is a perspective view of an embodiment in which the
main catheter is used for irrigation of emboli.
[0057] FIG. 27 is a perspective view of an embodiment in which a
distal occlusion device has a plurality of holes therein for
passing irrigation fluid across the treated occlusion.
[0058] FIG. 28 is a perspective view of an embodiment in which an
elongate member (e.g., a guidewire) has a plurality of holes
therein for passing irrigation fluid across the treated
occlusion.
[0059] FIGS. 29A and 29B are perspective views of an embodiment in
which a perfusion-filter located distal to the lesion to be treated
permits the perfusion of blood while entraining emboli produced as
a result of therapy.
[0060] FIGS. 30A is a perspective view of an alternative embodiment
in which emboli are captured in a perfusion-filter.
[0061] FIG. 30B is a cross sectional view of the main catheter of
the embodiment of FIG. 30A, illustrating lumens used for inflation
of the occlusive device, for delivering irrigation fluid, and for
passing an elongate member (e.g., a guidewire).
[0062] FIG. 31 is a perspective view of an embodiment in which
passive perfusion is performed with a hypotube having holes
therein.
[0063] FIGS. 32A and 32B are perspective views of a
perfusion-filter embodiment in which the occlusion of the vessel is
performed with the therapy catheter.
[0064] FIG. 33 shows a preferred embodiment of a syringe assembly
having features in accordance with the present invention and
operably coupled to an illustrative inflation adapter at a proximal
portion of a balloon guidewire catheter.
[0065] FIGS. 34A and 34B show open and closed positions,
respectively, of the sealing member, which is used with the balloon
guidewire catheter of FIGS. 33 and 35.
[0066] FIG. 35 shows a perspective view of the balloon guidewire
catheter of FIG. 33 placed within an open inflation adapter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0067] The preferred embodiments of the present invention provide
improved methods for containing and removing emboli resulting from
plaque, thrombi or other occlusions. The preferred methods are
particularly advantageous for use in the carotid artery and other
arteries above the aortic arch. The preferred methods may be used,
for example, in the treatment of a stenosis or an occlusion which
has a length and a width or thickness resulting in at least partial
occlusion of the vessel's lumen. Thus, the preferred methods are
effective in treating both partial and substantially complete
occlusions of arteries. It is to be understood that "occlusion" as
used herein, includes both complete and partial occlusions,
stenoses, emboli, thrombi, plaque, and any other substance which at
least partially occludes the lumen of the artery. Although the
methods disclosed herein are described with specific reference to
the carotid arteries, they can be applied to other vessels as well,
particularly bifurcated vessels.
[0068] As illustrated in FIG. 1, the common carotid artery 10 is
located in the neck and branches off into the internal carotid 12,
and the external carotid 14 arteries. The internal carotid artery
12 supplies blood to the brain, while the external carotid artery
14 supplies blood to the head and face. The preferred methods of
the present invention will be described for the treatment of an
occlusion within the internal carotid artery. It is to be
understood that this method can be used on other arteries as
well.
[0069] Generally, the preferred methods are adapted for the
percutaneous treatment, containment and removal of occlusions
within the carotid arteries or other arteries above the aortic
arch. In one of these methods, a main catheter having an occlusive
device on its distal end is first delivered to the common carotid
artery, proximal to the site of the occlusion. It should be noted
that, as used herein, "proximal" refers to the portion of the
apparatus closest to the end which remains outside the patient's
body, and "distal" refers to the portion closest to the end
inserted into the patient's body. The occlusive device is activated
to stop the downstream flow of blood. Collateral pressures from the
Circle of Willis and other vessels keep the blood flow in the
direction of the main catheter, preventing any emboli from moving
downstream. In another embodiment, a main catheter without an
occlusive device on its distal end, or a main catheter having an
occlusive device which is not deployed, is delivered to the common
carotid artery, proximal to the site of the occlusion.
[0070] In either case, an inner catheter having an occlusive device
on its distal end is delivered through the main catheter and across
the site of the occlusion. Alternatively, a detachable occlusive
device can also be used. In either case, the occlusive device is
activated at a site distal to the occlusion.
[0071] In some cases, a second inner catheter is used to provide a
third occlusive device. One inner catheter is delivered to the
internal carotid artery, while the other inner catheter is
delivered to the external carotid artery. When activated, the three
occlusive devices completely isolate the area surrounding the
occlusion to be treated.
[0072] A therapy catheter is then delivered to the site of the
occlusion to treat the occlusion. Such treatment includes, but is
not limited to, balloon angioplasty, thermal balloon angioplasty,
delivery of an intravascular stent, atherectomy, or radiation
treatment.
[0073] In one embodiment of the present invention, once therapy is
complete, an irrigation catheter is delivered into the working area
to provide irrigation fluid. Alternatively, anatomical irrigation
can be used, as explained below. Aspiration of the area surrounding
the treated occlusion is begun using either the main catheter or a
separate aspiration catheter. Blood flow is allowed into the
working area to be aspirated by deactivating the occlusive devices
on the main and/or inner catheters. This helps to irrigate the area
and ensure the removal of particles and debris from the artery.
[0074] In another embodiment of the present invention, the need for
a separate irrigation catheter and irrigation fluid are eliminated.
In the context of removing plaque, thrombi or other blockages from
blood vessels, separate irrigation fluid is generally provided
through an irrigation catheter to the site of treatment. It has
been discovered that the patient's own blood can be used as
irrigation fluid, without the need for delivery of a separate
irrigation catheter and irrigation fluid.
[0075] Although the patient's own flow of blood can provide an
irrigation source, situations sometime arise where providing
separate irrigation fluid is desired. In such cases a separate
catheter is introduced into the patient after the therapy catheter
is removed and is delivered within close proximity to the occlusive
device. Once the catheter is delivered proximal to the occlusive
device, the area is first aspirated through the catheter. By
delivering the catheter close to the occlusive device a turbulence
is created freeing debris from the edge of the occlusive device and
other areas where it may be trapped. The debris is then aspirated
from the patient. Following aspiration, irrigation fluid is
provided if desired to flush any remaining particles and debris
from the internal carotid.
[0076] Main Catheter
[0077] In the preferred methods, a main or guide catheter is first
introduced into the patient's vasculature. This catheter is used to
guide the insertion of other catheters and devices to the desired
site. A guide catheter (e.g., 9F) or a long sheath (e.g., 7F) may
be used as the main catheter. If the guide catheter is not
sufficiently stiff, then an angiography catheter may be positioned
inside the guide catheter, and both the guide catheter and the
angiography catheter can be delivered on a guidewire. (The term
guidewire is used broadly herein to include elongate members (such
as hollow or tubular members) made of metal as well as other
materials, such as plastic.) Once the guide catheter is properly
positioned, the angiography catheter can be removed. In some
embodiments of the present invention, the main catheter has an
occlusive device on its distal end. The occlusive device can be an
inflatable balloon, filter, expandable braid or other mechanical
occlusive device. The occlusive device should be capable of
preventing the migration of particles and debris from the working
area, either through total or partial occlusion of the vessel. Note
that the occlusion of the vessel need not be complete, and that
substantial occlusion of the vessel may be sufficient. The catheter
should be sized so as to slidably receive the inner, therapy and
intermediate (irrigation and/or aspiration) catheters inserted
therethrough.
[0078] FIG. 2 illustrates a side view of a catheter which can be
used as the outer or main catheter of the present system. Catheter
110 generally comprises an elongate flexible tubular body 116
extending between a proximal control end 112 and a distal
functional end 114. The tubular body 116 has a main lumen 130 which
extends between the ends 112 and 114. The main lumen 130 terminates
in a proximal opening 123 and a distal opening 127. A smaller
inflation lumen 132, configured in a side-by-side relationship with
the main lumen 130, extends along the length of the tubular body
116, and terminates within an occlusive device such as an occlusion
balloon 126 mounted on the distal end 114 of the catheter 110, as
described below. The inflation lumen 132, illustrated in FIGS. 3
and 4, is in fluid communication with the occlusion balloon 126,
such that fluid passing through the inflation lumen 132 may be used
to inflate or deflate the balloon 126. The proximal end of the
inflation lumen can terminate at one of the ports 122, 124 on the
proximal end of the catheter 110.
[0079] A control manifold 119 is provided at the proximal end 112
of the catheter 110. The control manifold 119 is generally provided
with a number of ports to provide access to the catheter lumen 130.
For example, for the embodiment depicted in FIG. 2, the control
manifold 119 is provided with a catheter end-access port 122 and a
catheter side-access port 124, to provide an introduction point for
the insertion of other catheters into the lumen 130. Ports 122 and
124 are preferably provided with standard Touhy Borst connectors,
although other types of connectors may be used. An inflation port
118, in fluid communication with the small inflation lumen 132, is
further provided on the manifold 119 for attachment of devices to
inflate or deflate the occlusion balloon 126. The manifold 119 is
also provided with an irrigation/aspiration port 120 which is in
fluid communication with the lumen 130, for attachment of devices
to provide irrigation fluid or aspiration pressure. Other
embodiments of the main catheter 110 may feature more or less
ports, depending upon the number of lumens in the catheter and the
desired functionalities of the catheter.
[0080] The manifold 119 is preferably formed out of hard polymers
or metals, which possess the requisite structural integrity to
provide a functional access port to the catheter lumen, such as for
balloon inflation or delivery of irrigation fluid and/or aspiration
pressure. In one preferred embodiment, the manifold 119 is
integrally formed out of polycarbonate. Of course, any suitable
material may be used to form the manifold 119, including
acrylonitrile butadiene styrene (ABS).
[0081] As illustrated in FIG. 2, an inflatable balloon 126 is
mounted on the distal end 114 of the catheter 110. The inflatable
balloon 126 will function as an occlusion balloon, to prevent blood
and debris from passing through the blood vessel distal to the
balloon 126. Thus, the inflatable balloon 126 is preferably able to
expand to fit a variety of different blood vessel diameters.
Accordingly, it is preferred that the inflatable balloon 126 have a
compliant expansion profile, tending to increase in radial diameter
with increasing inflation pressure. To achieve this, the balloon
126 may be made out of materials which impart such expansion
characteristics, including elastomeric materials such as latex or
irradiated polyethylene. In one preferred embodiment, the
inflatable balloon 126 is formed out of a material comprising a
block copolymer of styrene-ethylene-butylene-styrene, sold under
the trade name C-FLEX. Non-compliant balloons, such as those made
from PET can also be used. Further details as to balloons of this
type are disclosed in our copending application entitled
"Pre-Stretched Catheter Balloon", Ser. No. 08/812,140, filed Mar.
6, 1997, the entirety of which is incorporated by reference.
[0082] Alternatively, as illustrated in FIGS. 19-20, the main
catheter 406 does not include a distal occlusive device, or the
distal occlusive device on the main catheter is not used.
[0083] Inner Catheter
[0084] An inner catheter or guidewire having an occlusive device on
its distal end is preferably made of metals such as stainless steel
or nitinol, or plastics or composites. The preferred methods can be
effectively carried out using any of a number of guidewires or
catheters that perform the function of occluding the vessel and
allowing for the slidable insertion of various other catheters and
devices. The term "catheter" as used herein is therefore intended
to include both guidewires and catheters with these desired
characteristics.
[0085] A preferred inner catheter is illustrated in FIGS. 5 and 6.
The catheter apparatus 310 is generally comprised of four
communicating members including an elongated tubular member 314, an
inflatable balloon member 316, a core-wire member 320 and a coil
member 322. The catheter apparatus 310 is preferably provided with
an outer coating of a lubricous material, such as TEFLON.
[0086] The body member 314 of the catheter apparatus 310 is in the
form of hypotubing and is provided with proximal and distal ends
314A and 314B as well as an inner lumen 315 extending along the
tubular member 314. The balloon member 316 is coaxially mounted on
the distal end 314B of the tubular member 314 by suitable adhesives
319 at a proximal end 316A and a distal end 316B of the balloon
member 316 as in the manner shown in FIG. 6. The core-wire member
320 of the catheter 310 may be comprised of a flexible wire 320.
The flexible wire 320 is joined by adhesives, soldering, brazing or
crimping at a proximal end 320A of the flexible wire 320 to the
distal end 314B of the tubular member 314 as in the manner show in
FIG. 6.
[0087] Preferably, the proximal end 320A of the flexible wire 320
has a transverse cross sectional area substantially less than the
smallest transverse cross-sectional area of the inner lumen 315 of
the tubular member 314. In the preferred embodiment, the flexible
wire 320 tapers in the distal end 320B to smaller diameters to
provide greater flexibility to the flexible wire 320. However, the
flexible wire may be in the form of a solid rod or a ribbon or
combinations thereof.
[0088] As shown in FIG. 6, the distal end 320B of the flexible wire
320 is secured to a rounded plug 318 of solder or braze at the
distal end 322B of the coil member 322. The coil member 322 of the
catheter 310 may be comprised of a helical coil 322. The coil
member 322 is coaxially disposed about the flexible wire 320, and
is secured to the flexible wire 320 by soldering, brazing or
adhesives at about the proximal end 320A of the flexible wire 320
as in the manner shown in FIG. 6.
[0089] The balloon member 316 is preferably a compliant balloon
formed of a suitable elastic material such as a latex or the like,
but can be made of non-compliant materials as well. The flexible
coil 322 is preferably formed of a wire of platinum based alloys or
gold. The flexible core-wire 320 and the tubular member 314 are
preferably formed of a nickel-titanium alloy or stainless
steel.
[0090] Once the inner catheter has been properly positioned inside
the carotid artery at a point distal to the occlusion, the
occlusive device at the distal end of the inner catheter is
actuated to occlude the vessel distal to the existing occlusion to
create a working area. When a detachable occlusive device is used,
the occlusive device is positioned at a point distal to the
occlusion to be treated, and activated to occlude the artery. It is
to be understood that the stenosis or occlusion could be in a
discrete location or diffused within the artery. Therefore,
although placement of the occlusive device is said to be distal to
the stenosis or occlusion to be treated, portions of the diffused
stenosis or occlusion may remain distal to the occlusive
device.
[0091] Therapy Catheter
[0092] After the area surrounding the occlusion has been isolated,
a therapy catheter then is delivered to the site of the occlusion.
The term "therapy catheter" is meant to include any of a number of
known devices used to treat an occluded vessel. For example, a
catheter carrying an inflatable balloon for use in balloon
angioplasty can be delivered to dilate the occlusion. Thermal
balloon angioplasty includes the use of heat to "mold" the vessel
to the size and shape of the angioplasty balloon. Similarly, an
intravascular stent can be delivered via a balloon catheter and
deployed at the site of the occlusion to keep the vessel open.
Cutting, shaving, scraping or pulverizing devices can be delivered
to excise the occlusion in a procedure known as atherectomy. A
laser or ultrasound device can also be delivered and used to ablate
plaque in the vessel. Thrombectomy devices can be used, as can
rheolitic devices, and devices which create a venturi effect within
the artery. Various thrombolytic or other types of drugs can be
delivered locally in high concentrations to the site of the
occlusion. It is also possible to deliver various chemical
substances or enzymes via a catheter to the site of the stenosis to
dissolve the obstruction. The term "therapy catheter" encompasses
these and similar devices.
[0093] Aspiration and Irrigation Catheters
[0094] After the therapy has been performed and the occlusion has
been treated, the working area may be aspirated to remove fluid and
debris. Aspiration can be provided through the main catheter if
desired. A source of negative pressure is attached at the proximal
end of the main catheter, and fluid and debris are aspirated
through the main catheter's main lumen. Alternatively, an
aspiration catheter or similar debris removing device can be
delivered to the working area to remove particles and any other
debris. The term "aspiration catheter" includes any device which
creates an area of fluid turbulence and uses negative pressure to
aspirate fluid and debris, and includes thrombectomy catheters,
rheolitic devices and those devices which create a venturi effect
within the vessel. Thus, it is possible that a single catheter is
used as both the therapy catheter and the aspiration catheter.
[0095] An aspiration catheter particularly suited for use with the
preferred methods is illustrated in FIG. 7. The catheter 260
includes an adapter 262 and a seal at its proximal end. The
catheter 260 further includes an aspiration port 264 to which a
source of negative pressure is attached. The aspiration catheter
further comprises a long hollow shaft 266 having a distal end 268.
The distal tip 268 can/include a radiopaque marker to aid in
locating the tip 268 during insertion into the patient, and is
preferably soft to prevent damage to the patient's vasculature.
[0096] The aspiration catheter illustrated in FIG. 7 is an
over-the-wire catheter. As seen in FIG. 8, the catheter shaft 266
is hollow. During insertion of the aspiration catheter 260, the
proximal end of a guidewire 270 is inserted into the distal end of
the aspiration catheter 268, and the aspiration catheter 260 is
slidably advanced over the guidewire 270, which is positioned
inside the hollow lumen 272 of the aspiration catheter 260. The
position of the guidewire 270 relative to the shaft 260 of the
aspiration catheter 260 is illustrated in FIG. 9, but of course,
can vary. For this type of aspiration catheter 260, a very long
guidewire 270, generally around 300 centimeters in length, is used
to facilitate the insertion of the aspiration catheter 260 over the
guidewire 270.
[0097] Alternatively, the aspiration catheter 280 can be of a
single operator design, as illustrated in FIGS. 10-11. The catheter
280 has an adapter and an aspiration port at its proximal end. Like
the over-the-wire aspiration catheter 260 the single operator
aspiration catheter 280 further comprises a long hollow shaft 282
having a distal end 288. The distal tip 288 can include a
radiopaque marker to aid in locating the tip 288 during insertion
into the patient, and is preferably soft to prevent damage to the
patient's vasculature. At the distal end of the shaft 288, a
guidewire lumen 286 is attached. This lumen 286 provides a separate
lumen, apart from the main aspiration lumen 284 of the catheter
280, for the insertion of the guidewire. This guidewire lumen 286
can be as short as 5 centimeters or longer. As illustrated in FIG.
11, during delivery of the aspiration catheter 280, the proximal
end of the guidewire is inserted into the distal end of the
guidewire lumen 286, and the guidewire lumen 286 is slidably
advanced over the guidewire. Unlike the over-the-wire catheter 260
described above, only a short segment of the single operator
aspiration catheter 280 rides over the guidewire, and the guidewire
remains in the guidewire lumen 286 and does not enter the
aspiration lumen 284 of the aspiration catheter 280. With the
single operator system 280, the long guidewire used with the
over-the-wire catheter 260, and the extra operator needed to handle
it, are not required.
[0098] Although the guidewire lumen 286 is shown in FIG. 10 as
being located only on the distal end 288 of the shaft of the
aspiration catheter 280, the lumen 286 can also be made to extend
the entire length of the shaft 280 if desired. In both embodiments,
the aspiration lumen 284 is advantageously left completely
unobstructed to provide more efficient aspiration. The guidewire
lumen 286 can also include a slit in the outside wall of the lumen
to facilitate faster and easier insertion and removal of the
guidewire through the side wall of the lumen.
[0099] In another embodiment not shown, the aspiration catheter can
be configured such that the therapy catheter can be inserted
through the lumen of the aspiration catheter. The lumen is made
large enough to accommodate the desired therapy catheter. This
allows the aspiration catheter and the therapy catheter to be
delivered into the patient at the same time. When therapy is
complete, the therapy catheter is removed while the aspiration
catheter remains in place. This eliminates the need to separately
deliver the aspiration catheter after removal of the therapy
catheter, saving valuable time.
[0100] In yet another embodiment, also not shown, the therapy
catheter can be built over the aspiration catheter. For example, a
dual or triple lumen catheter having a dilatation balloon at its
distal end can be used. One lumen is used to inflate the dilatation
balloon to be used for angioplasty, while the second lumen is used
for aspiration. The third lumen is used as a guidewire lumen.
Alternatively, the aspiration catheter can be designed to deploy a
stent within the occluded artery, or could include an atherectomy
device on its distal end. These designs allows a single combined
aspiration catheter and therapy catheter to be delivered into the
patient. When therapy is complete, aspiration is carried out
without the need to first remove the therapy catheter or separately
deliver an aspiration catheter.
[0101] FIG. 12 is a side view of an irrigation catheter 140 or
aspiration catheter which may be utilized in the preferred methods.
It should be understood that when an irrigation catheter is used,
aspiration occurs through the outer pathway between the irrigation
and main catheters, while irrigation occurs through the irrigation
pathway. Similarly, when an aspiration catheter is used, aspiration
occurs through the aspiration catheter while irrigation occurs
through the pathway between the aspiration and main catheters.
Irrigation fluid is supplied under pressure at the proximal end of
the catheter 142 and delivered through the side holes 146 and
through the distal end of the catheter 144. Alternatively,
aspiration can be provided at the proximal end of the catheter 142
and fluid and debris aspirated through the side holes 146 and
through the distal end of the catheter 144. The catheter 140 can be
about 125 centimeters in length and constructed from a plastic
material such as HYTREL tubing or high density polyethylene (HDPE)
or PEBAX (Atochem, France). In order to achieve a softer distal
section, the durometer of the tube 148 material is reduced in the
distal section to about 55 whereas that of the proximal section 142
is higher, such as about 80. Proximal valves and fittings which are
well known in the art can be mounted on the catheter 140 of FIG.
12.
[0102] FIGS. 13-16 illustrate another type of irrigation or
aspiration catheter 230, a single operator catheter, which can be
used in the present system. In the case of the irrigation catheter,
irrigation is through the inner pathway and aspiration is through
the outer pathway. If the catheter is used for aspiration,
aspiration is through the inner pathway and irrigation is through
the outer pathway. As shown in FIGS. 13-16, the catheter 230 has an
adaptor 232 on its proximal end. This single operator catheter 230
further comprises a long tubular body 236 having a distal end 238.
The distal tip 238 can include a radiopaque marker to aid in
locating the tip 238 during insertion into the patient, and is
preferably soft to prevent damage to the patient's vasculature. At
the distal end of the shaft 238, an inner catheter lumen 240 is
attached. This lumen 240 provides a separate lumen, apart from the
main irrigation or aspiration lumen 242 of the catheter 230, for
the insertion of the inner catheter, and has an inner diameter
sized to received the inner catheter. In a preferred embodiment,
the inner diameter of the lumen is about 0.016" to about 0.020",
and more preferably is about 0.019". This inner catheter or
guidewire lumen can be as short as 5 centimeters, but can extend 30
centimeters or longer in a proximal direction. During delivery of
the catheter 230, the proximal end of the inner catheter is
inserted into the distal end of the inner catheter lumen 240, and
the lumen 240 is slidably advanced over the inner catheter. Only a
short segment of the single operator catheter 230 rides over the
inner catheter, and the inner catheter remains in the lumen 240 and
does not enter the main lumen 242 of the catheter 230.
[0103] Although the inner catheter lumen 240 is shown in FIG. 13 as
being located only on the distal end 238 of the shaft of the
catheter 236, the lumen 240 can also be made to extend the entire
length of the shaft 236 if desired. In both embodiments, the main
lumen 242 is advantageously left completely unobstructed to provide
more efficient irrigation or aspiration. As seen in FIG. 16, the
inner catheter lumen 240 can also include a slit 241 or weakened
area in the outside wall of the lumen 240 along the entire length
of the lumen 240 to facilitate faster and easier insertion and
removal of the inner catheter through the side wall of the lumen
240. By inserting and removing the inner catheter through the side
wall of the lumen 240 on the catheter 236, the need to remove
adapters and attachments from the proximal end prior to slidably
advancing or removing the catheter 236 over the inner catheter is
eliminated. It should be understood that this slit 241 or weakened
area through which the inner catheter can be inserted and removed
can exist on the intermediate catheter regardless of whether the
catheter is used for irrigation, aspiration, therapy or some other
purpose.
[0104] In another embodiment, not shown, the irrigation and
aspiration are conducted through a multi lumen catheter. In this
embodiment, a single catheter is used. The catheter includes at
least two separate lumens; one lumen is used for aspiration and has
a source of negative pressure attached at the proximal end, while a
second lumen is used to provide irrigation and has a source of
irrigation fluid attached at the proximal end.
[0105] Additional details relative to the catheters described above
are found in copending applications Ser. Nos. 08/813,023,
08/812,140, 08/813,808 and 08/812,876, filed on Mar. 6, 1997,
entitled "Catheter for Emboli Containment", "Prestretched Catheter
Balloon", "Aspiration Catheter", and "Hollow Medical Wires and
Methods of Constructing Same", all of which are hereby incorporated
by reference.
[0106] Preferred Methods
[0107] A. Dual Balloon System
[0108] FIG. 17 illustrates the removal of plaque and any associated
thrombi from the internal carotid artery 400. It should be noted
that this method is merely exemplary, and that occlusions in other
locations, such as within the external carotid 402, common carotid
404 artery, or other arteries above the aortic arch, may be
treated.
[0109] A main catheter or guide catheter 406 is introduced into the
patient's vasculature through an incision in the femoral artery in
the groin of the patient, or through direct access to the arteries
in the neck (e.g., jugular access, in which case the catheters do
not need to be as long as in the case of femoral access). The main
catheter 406 has a lumen sized to receive other catheters and
devices, and can be used to guide the insertion of these other
catheters and devices. The main catheter 406 is guided through the
vasculature until it reaches the common carotid artery 404, where
it can remain in place throughout the procedure. Fluoroscopy is
typically used to guide the main catheter 406 and other devices to
the desired location within the patient. The devices are frequently
marked with radiopaque markings to facilitate visualization of the
insertion and positioning of the devices within the patient's
vasculature.
[0110] Once the main catheter 406 is in place, with its occlusive
device 408 at a position proximal to the occlusion 410, the
occlusive device 408 is activated. Downstream blood flow is
effectively stopped, and blood flow coming from collateral blood
vessels distal to the occlusive device prevents the downstream
migration of any free particles. In this example, the occlusive
device 408 is an inflatable balloon. The balloon is inflated to
occlude the common carotid artery 404.
[0111] Next, an inner catheter or guidewire 420 having an occlusive
device 422 at its distal end is delivered through the main catheter
406 into the internal carotid artery 400 and past the site of the
occlusion 410. Alternatively, a detachable occlusive device can be
deployed at the site distal to the occlusion, and the delivery
device removed. In this example, the occlusive device 422 is also
an inflatable balloon. The balloon is inflated to occlude the
internal carotid artery at a site distal to the occlusion 410. It
should be understood that the occlusion within the artery can be in
a discrete location or diffused within the vessel. Therefore,
although placement of the distal occlusive device is said to be
distal to the occlusion to be treated, portions of the diffuse
occlusion may remain distal to the occlusive device.
[0112] A working area is therefore created between the two
occlusive devices 408, 422 surrounding the occlusion 410. A therapy
catheter (not shown) is then delivered. The therapy catheter can be
any of a number of devices, including a balloon catheter used to
perform angioplasty, a catheter which delivers a stent, a catheter
for delivering enzymes, chemicals, or drugs to dissolve and treat
the occlusion, an atherectomy device, a thrombectomy device, a
rheolitic device, a device which creates a venturi effect within
the artery, or a laser or ultrasound device used to ablate the
occlusion.
[0113] Once the desired therapy is performed, the therapy catheter
is withdrawn from the patient's body and an aspiration catheter 424
is delivered through the main catheter 406, preferably over the
inner catheter or guidewire 420. The aspiration catheter 424 rides
over the guidewire 420 with the guidewire 420 inserted through the
aspiration lumen of the catheter 424. Alternatively, a single
operator type aspiration catheter can be used, in which only a
portion of the aspiration catheter rides over the guidewire, which
is inserted into a separate guidewire lumen. FIG. 17 illustrates
the treatment site after the over-the-wire aspiration catheter 424
is inserted into the internal carotid artery 400.
[0114] After the aspiration catheter 424 is in place, aspiration is
begun. A source of negative pressure is connected to the aspiration
catheter 424 at its proximal end. A preferred source of negative
pressure is any container containing a fixed vacuum, such as a
syringe, attached to the proximal end of the aspiration catheter
424 at the aspiration port. A mechanical pump or bulb or any other
appropriate source of negative pressure can also be used, including
the creation of a venturi effect within the blood vessel. The
difference between the existing pressure within the vessel and the
aspiration or negative pressure within the vessel should not exceed
about 50 psi. If too much aspiration is applied, the change in
pressure in the vessel will be too great and damage may occur to
the vessel itself.
[0115] Prior to aspiration, simultaneous with aspiration, or after
aspiration is begun, the proximal occlusive device 408 is
deactivated to allow blood flow into the area. The blood flow into
the area provides irrigation fluid which creates turbulence and
facilitates the removal of particles and debris. Preferably, the
anatomical irrigation pressure provided is approximately 1-1.5 psi,
and the blood flow into the area is at least 10 cubic
centimeters/min and more preferably about 60-80 cubic
centimeters/min. In a preferred embodiment, the proximal occlusive
device is then reactivated, and the distal occlusive device is
deactivated. This allows blood flow into the working area from the
distal end. Following aspiration, the distal occlusive device is
reactivated. This method of alternately deactivating and
reactivating the occlusive devices acts to contain and direct the
emboli to an area within the working area where they will be
aspirated. Particles are initially contained between the two
occlusive devices. When the proximal occlusion device is
deactivated, blood flow forces particles and debris toward the
distal end of the working area. The working area is aspirated, and
the occlusive device reactivated. When the distal occlusive device
is deactivated, blood flow forces particles and debris back toward
the proximal end of the working area, where they are then
aspirated. The steps of deactivating and reactivating the occlusive
devices and aspirating the working area can be repeated as often as
desired, until the working area is substantially free of particles
and debris.
[0116] When the deactivating and reactivating of the occlusive
devices and aspiration steps are complete, the aspiration catheter
is removed, and the occlusive devices are deactivated. The main and
inner catheters are also removed from the patient.
[0117] As described above, the aspiration catheter can be sized
such that it can receive the therapy catheter within its lumen. In
this case, the aspiration catheter and the therapy catheter are
delivered into the artery together. When therapy is complete, the
therapy catheter is removed while the aspiration catheter remains
in place. When aspiration is complete, the aspiration catheter,
inner catheter and main catheter are removed from the patient's
body. Delivering the aspiration catheter and therapy catheter
together saves time, which is critical during these types of
procedures.
[0118] In yet another embodiment, aspiration takes place through
the lumen of the inner catheter or guidewire. The occlusive device
on the inner catheter is positioned distal to the occlusion, and
the occlusive device is activated to at least partially occlude the
vessel. The therapy catheter is delivered and therapy performed. A
source of negative pressure is provided at the proximal end of the
inner catheter, and aspiration occurs through openings located at
the distal end of the catheter just proximal to the occlusive
device. This eliminates the need for a separate aspiration
catheter, and the need to remove the therapy catheter prior to
aspiration. Again, this saves time, which is critical during these
types of procedures.
[0119] B. Triple Balloon System
[0120] In another embodiment illustrated in FIG. 18, a third
occlusive device 430 is used to occlude the external carotid artery
402. Once the main catheter 406 is in place and the common carotid
artery 404 is occluded, inner catheters 420, 432 are delivered to
both the internal 400 and external 402 carotid artery branches and
occluded. Following therapy and aspiration of the internal carotid
artery 400, the aspiration catheter is moved in a proximal
direction, and delivered over the inner catheter 420 into the
external carotid artery branch 402. Aspiration is then performed in
that branch to remove any particles or debris that may have been
moved into the external carotid artery 402. The three occlusive
devices can be alternately deactivated and reactivated as described
above, to ensure the desired clearance of the working area. When
aspiration is complete, the occlusive devices are deactivated, and
the main 406, aspiration, and inner catheters 420, 432 are removed
from the patient.
[0121] Should it be desired that a separate irrigation catheter be
used to provide irrigation fluid, an irrigation catheter can be
delivered to the site of the occlusion following therapy and
removal of the therapy catheter. The irrigation catheter is
delivered through the main catheter and over the inner catheter.
Irrigation fluid is provided through the irrigation catheter, while
aspiration is provided through the main catheter.
[0122] C. Single Balloon System
[0123] In another embodiment illustrated in FIG. 19, only a single
occlusive device is used. As described above, a main catheter 406,
with or without a distal occlusive device, is introduced into the
patient's vasculature through an incision in the femoral artery in
the groin of the patient or through direct access to the arteries
in the neck. The main catheter 406 is guided through the
vasculature until it reaches the common carotid artery 404, where
it can remain in place throughout the procedure.
[0124] Once the main catheter 406 is in place proximal to the
occlusion 410, an inner catheter or guidewire 420 having an
occlusive device 422 at its distal end is delivered through the
main catheter 406 into the internal carotid artery 400 and past the
site of the occlusion 410. Alternatively, a detachable occlusive
device can be deployed at the site distal to the occlusion, and the
delivery device removed. In this example, the occlusive device 422
is an inflatable balloon. The balloon is inflated to occlude the
internal carotid artery 400 at a site distal to the occlusion 410.
As noted before, it should be understood that the occlusion within
the artery can be in a discrete location or diffused within the
vessel. Therefore, although placement of the distal occlusive
device is said to be distal to the occlusion to be treated,
portions of the diffuse occlusion may remain distal to the
occlusive device.
[0125] A therapy catheter, not shown, is then delivered. Again, the
therapy catheter can be any of a number of devices, including a
balloon catheter used to perform angioplasty, a catheter which
delivers a stent, a catheter for delivering enzymes, radiation,
chemicals, or drugs to dissolve and treat the occlusion, an
atherectomy device, a thrombectomy device, a rheolitic device, a
device which creates a venturi effect within the artery, or a laser
or ultrasound device used to ablate the occlusion.
[0126] Once the desired therapy is performed, the therapy catheter
is withdrawn from the patient's body and an intermediate catheter
426 is delivered through the main catheter 406. A single operator
type catheter may be used in which only a portion of the catheter
rides over the guidewire, which is inserted into a separate
guidewire lumen (as illustrated in FIG. 20). Alternatively, an
over-the-wire type catheter can be used. The intermediate catheter
426 is delivered into the internal carotid artery 400 to a location
just proximal to the occlusive device 422. Preferably, in order to
maximize the effectiveness of the aspiration or irrigation, the
catheter 426 is positioned less than two centimeters from the
proximal end of the occlusive device 422 at some point during
aspiration. Delivering the intermediate catheter 426 in such close
proximity to the occlusion device 422 will allow the creation of a
turbulent effect near the occlusive device during aspiration and
irrigation thus aiding in the removal of the particles and debris.
During aspiration, the intermediate catheter 426 can be moved in a
proximal direction, to ensure more effective aspiration of the
area.
[0127] Delivery of the intermediate catheter 426 near the occlusive
device 422 requires passing the intermediate catheter 426 across
the previously occluded vessel. In order to minimize the risk to
the patient the intermediate catheter 426 is preferably soft, small
and flexible. A preferred embodiment of this invention comprises
delivering a soft-tipped intermediate catheter 426 made of a
compound of a durometer 55 or less.
[0128] Once the intermediate catheter 426 is delivered in close
proximity to the occlusive device 422, the area is first aspirated.
As noted above, the intermediate catheter 426 can be moved backward
in a proximal direction during aspiration. This forward and
backward movement of the intermediate catheter 426 can be repeated
as often as desired to provide effective aspiration. At some point
during aspiration, the distal end of the aspiration catheter should
be positioned about 2 cm or less from the proximal end of the
occlusive device to ensure effective aspiration. Following
aspiration, the area is irrigated by supplying a fluid, such as
saline, through the intermediate catheter 426. The irrigation fluid
acts to flush any remaining particles or debris from the internal
carotid 400, to the external carotid 402, as indicated by the
arrows in FIG. 21. The steps of sequential aspiration and
irrigation or flushing, can be repeated as many times as necessary
to remove all of the particles and debris from the vessel.
[0129] In one embodiment, the intermediate catheter 426 has a
single lumen for delivery of aspiration pressure and irrigation
fluid, such as the aspiration or irrigation catheters shown in
FIGS. 7 through 16. The proximal end of the intermediate catheter
426 is connected to a source of negative pressure (as described
above) and is used to aspirate the debris and particles around the
occlusive device 422.
[0130] Following aspiration of the area, the proximal end of the
intermediate catheter 426 is connected to a source of irrigation
fluid, such as saline, in order to irrigate the area near the
occlusive device 422. Preferably, the volume of fluid used to
irrigate the area near the occlusive device 422 is equal to or
greater than the volume of the area between the proximal end of the
distal occlusive device and the start of the internal carotid
artery at the bifurcation of the common carotid artery. For
example, at least 10 cubic centimeters of fluid is delivered to the
area that is between the distal occlusive device and the start of
the internal carotid branch, which is approximately 1-5 cubic
centimeters. As a result of this irrigation, any particles or
debris remaining in the internal carotid 400 will be flushed into
the external carotid 402.
[0131] In yet another embodiment, the intermediate catheter 426 has
two lumens, one for aspiration and another for irrigation. The
lumen providing aspiration is attached at its proximal end to a
negative pressure source. A second lumen is attached at its
proximal end to source of irrigation fluid. An advantage of this
embodiment is that the particles and debris removed are in a
separate lumen, eliminating the possibility that they could be
flushed back into the vessel when the irrigation fluid is delivered
through the same lumen as the aspiration pressure. As with the
single lumen embodiment, the steps of aspirating and irrigating can
be repeated as many times as necessary. Once the emboli have been
flushed away, the distal occlusive device may be deactivated and
removed from the patient.
[0132] As illustrated in FIG. 22, after the occlusion 410 has been
treated, the distal end of the intermediate catheter 426 may be
advantageously placed distal to the treated occlusion, i.e.,
between the treated occlusion 410' and the occlusive device 422.
This facilitates more thorough flushing of the region between the
occlusive device 422 and the treated occlusion 410', and around the
treated occlusion generally, so that any particles and debris
remaining after therapy can be more effectively removed as the
aspiration fluid (i.e., blood from the common carotid) passes
across the treated occlusion 410'.
[0133] Flushing of the region in and around the treated occlusion
410' may be accomplished in a number of ways. For example, as
illustrated in FIG. 23, the intermediate catheter 426 may be used
as an aspiration catheter. Alternatively, as illustrated in FIG.
24, the intermediate catheter 426 may be used as an irrigation
catheter, in which particles and debris are flushed towards the
point where the common carotid 404 intersects the internal carotid
400, and towards the external carotid 402. Upon reaching the
external carotid 402, particles, debris, and emboli are flushed
down the external carotid with anatomical blood flow. The therapy
catheter 448 of FIG. 24A may also be used for irrigation following
therapy, in which saline solution is pumped through the annulus
between the therapy catheter 448 and the guidewire 420. The therapy
catheter 448 advantageously comprises a therapy device (such as a
balloon for balloon angioplasty, a stent, an atherectomy device for
cutting away plaque, or a rheolitic catheter) for use after the
occlusive device 422 is deployed.
[0134] The steps illustrated by FIGS. 23 and 24 may be performed
sequentially, i.e., the intermediate catheter 426 may first be used
as an aspiration catheter and then as an irrigation catheter. In
FIGS. 23 and 24 (or 24A), the distal end of the catheter 426 (or
therapy catheter 448) is preferably positioned beyond the treated
occlusion 410' to more efficiently remove emboli from the treated
region. In general, aspiration is performed as close to the
occlusive device 422 as possible. The intermediate catheter 426
(like the therapy catheter 448) is advantageously separate from the
guidewire 420 and slidable on it, so that the catheter 426 may be
properly positioned by the user.
[0135] The main (outer) catheter 406 itself may be used for
aspiration and irrigation of the region in and around the treated
occlusion 410', as illustrated in FIGS. 25 and 26, respectively.
The main catheter 406 has a radial extent that permits the therapy
catheter 448 and the intermediate catheter 426 to pass through the
main catheter 406. In FIG. 25, the distal end of the main catheter
406 is positioned distal to the treated occlusion 410', and blood
containing emboli or other particles is aspirated away into the
main catheter and removed from the patient. In FIG. 26, the main
catheter 406 is used to flush the region in and around the treated
occlusion 410' by ejecting, for example, saline solution which then
transports particles and debris away from the internal carotid 400
and down the external carotid 402. Either of the treatment methods
illustrated by FIGS. 25 and 26 may be used to flush away particles,
or both may be used sequentially, e.g., the main catheter 406 may
be used for aspiration and then for flushing. (However, the
presently preferred methods utilize the main catheter 406 only for
irrigation.)
[0136] Other combinations of the methods illustrated by FIGS. 23-26
can be utilized. For example, the intermediate catheter 426 of FIG.
23 may be used for aspiration, followed by flushing with the main
catheter 406 (as illustrated in FIG. 26). Also, the main catheter
406 may be used for aspiration (as illustrated in FIG. 25),
followed by flushing with the intermediate catheter 426 (as
illustrated in FIG. 24). In general, the best results are obtained
by first aspirating (thereby removing particles from the patient)
and then flushing, and the aspirating and flushing steps may be
repeated as necessary. The same catheter can be used for aspiration
and then irrigation, but in this case, this catheter should be
removed from the patient and cleaned after aspiration to remove
emboli from it. Irrigation then removes any emboli remaining in the
patient. (However, if the main catheter 406 is used for both
aspiration and irrigation, this cleaning step should be foregone
since the main catheter 406 should be the last catheter to be
removed from the patient.) It is preferred, however, to use a
separate aspiration catheter and irrigate through the main catheter
406.
[0137] Aspiration and irrigation may be performed simultaneously by
having two catheters deployed at the same time and irrigating
through one (e.g., the therapy catheter 448 or the intermediate
catheter 426) and aspirating through another (e.g., the main
catheter 406). In this case, the main catheter 406 may be deployed
to a location near the intersection of the internal carotid 400 and
the external carotid 402. Alternatively, aspiration may be
performed through the intermediate catheter 426 while irrigating
through the main catheter 406, in which the distal ends of the
intermediate catheter 426 and the main catheter 406 are preferably
positioned distal and proximal, respectively, to the treated lesion
410'.
[0138] As shown in FIG. 27, flushing may also be performed in a
blood vessel (not necessarily a bifurcated vessel as illustrated
herein), using an occlusive device 422' that passes saline solution
(or another suitable flushing solution). In this embodiment, the
saline solution may be advantageously passed through a lumen in the
guidewire 420 and into the occlusive device 422'. The occlusive
device 422' has at least one fluid flow opening and is preferably
microporous on its proximal end, having a plurality of holes 450
(e.g., 10-50) that are preferably less than 1000 microns in
diameter and more preferably between 50 and 100 microns in
diameter. The holes may be formed in the occlusive device 422' by
laser drilling, for example. As saline solution passes through the
occlusive device 422' and into the internal carotid 400, emboli,
particulates, and other debris are flushed past the treated
occlusion 410' and down the external carotid 402. During
irrigation, the fluid flow may be maintained with a pressurized
syringe located outside the patient. However, while therapy is
being performed on the occlusion 410, the fluid flow may be
advantageously reduced to avoid overpressurizing that segment of
the internal carotid artery 400 between the occlusion device 422'
and the occlusion 410 (pressures should be kept less than 50 psi).
Thus, the saline solution is used for inflating the occlusive
device 422' as well as for irrigating emboli from the internal
carotid 400 down the external carotid 402. The irrigation method of
FIG. 27 may be augmented by aspirating the region in and around the
treated occlusion 410' through a catheter, e.g., through the
intermediate catheter 426 (as in FIG. 23) or the main catheter 406
(as in FIG. 25).
[0139] Another irrigation device and method is disclosed in FIG.
28, in which one or more holes 460 in the guidewire 420 are located
distal to the treated lesion 410' and proximal to the occlusive
device 422. (For example, 1, 2, or 3 holes of dimensions
0.050".times.0.002-0.003" may be used, or 10 holes of dimensions
0.003".times.0.003", to provide a flow such that the pressure
inside the vessel does not exceed 50 psi.) Irrigation fluid is
pumped through the guidewire 420 and out of the holes 460 (which
may advantageously be 50-300 microns in diameter) to flush away
emboli from the treated lesion 410' and down the external carotid
402. The guidewire 420 may have a single lumen (not shown) that is
in fluid communication with both the internal carotid artery 400
(via the holes 460) and the occlusive device 422, in which case the
irrigation fluid and the fluid used to inflate the occlusive device
422 are the same. Alternatively, the guidewire 420 may have
dedicated lumens (not shown) for irrigation and inflation. The
irrigation method of FIG. 28 may be augmented by aspirating the
region in and around the treated occlusion 410' through a catheter,
e.g., through the intermediate catheter 426 (as in FIG. 23) or the
main catheter 406 (as in FIG. 25).
[0140] Instead of pumping irrigation fluid through the holes 460 as
shown in FIG. 28, a larger slot (not shown) of dimensions
0.005".times.0.100-0.200" may be cut into the guidewire 420 and
then covered with a braid (not shown) that extends 0.010-0.030"
beyond the edges of the slot. As irrigation fluid is passed through
the guidewire 420, the braid expands, permitting the irrigation
fluid to pass out of the slot and into the internal carotid 400.
Instead of using a braid, this slot may alternatively be covered
with a plastic sheath (not shown) having a plurality of slits or
pores (not shown) which are in fluid communication with the slot.
Ten pores having a diameter of 50-100 microns may advantageously be
used.
[0141] Irrigation rates for the methods disclosed herein are
preferably between 0.1 cc/sec and 3 cc/sec, more preferably between
0.5 and 1.5 cc/sec, and still more preferably about 1 cc/sec.
Aspiration rates are preferably between 0.5 and 5 cc/sec, and more
preferably between 0.5 and 1.1 cc/sec. The fluid pressure used to
generate the irrigation and aspiration rates may be pulsed on and
off to better flush away emboli. For example, fluid pressure may be
alternately applied for 5 seconds (in the form a pulse) and then
turned off for 2-3 seconds. In general, fluid is irrigated (or
aspirated) through a lumen in a catheter, with the lumen being in
fluid communication with a fluid flow opening at a distal end
portion of the catheter.
[0142] The single balloon methods disclosed herein may additionally
comprise inflating a balloon on the main catheter 406 within the
common portion of the vessel to occlude the common portion.
[0143] D. Alternate Dual Balloon System
[0144] Under certain circumstances, use of a second occlusive
device is desired, as illustrated in FIG. 21. The second occlusive
device 432 is positioned on the distal end of the main catheter 406
and acts to occlude the main carotid artery 404. A second occlusive
device 432 may be desired where the physician is concerned about
crossing the occlusion 410 in the internal carotid artery 400 with
the inner catheter 420 or where there is another occlusion 428 in
the external carotid artery 402 resulting in decreased flow through
the external carotid 402.
[0145] Once the main catheter 406 is delivered to the common
carotid artery 404, the occlusive device 432 is activated. The
activation of the occlusive device 432 will have the effect of
occluding the common carotid artery 404 thereby cutting off the
blood flow to both the internal carotid 400 and the external
carotid 402 arteries.
[0146] Next, an inner catheter 420 with an occlusive device 422 is
delivered distal to the occlusion 410 in the internal carotid
artery 400 and activated, thus isolating the occlusion 410 between
the two occlusive devices 432, 422. This is followed by therapy on
the occlusion 410 as described above. Sequential aspiration and
irrigation are then performed as described above.
[0147] The main advantage of using two occlusive devices is that
when the internal carotid artery 400 is irrigated, a back pressure
is created in the chamber defined by the proximal occlusive device
432 and the distal occlusive device 422. This back pressure will
force the fluid, particles and debris from the internal 400 and
common 404 carotid arteries through the external carotid artery
402.
[0148] E. Alternate Triple Balloon System
[0149] In some cases, a triple balloon system is used. This system
is especially advantageous in those patients where occlusion of the
common carotid artery results in blood from collateral vessels
flowing from the external carotid artery to the internal carotid
artery. The direction of blood flow in a particular patient can be
determined through angiography.
[0150] In this system (not shown), following activation of the
occlusive device in the common carotid artery, but before crossing
the occlusion with an inner catheter, a first inner catheter with
an occlusive device is delivered to the external carotid artery and
the occlusive device activated. This prevents flow from collateral
blood vessels moving from the external to the internal carotid
artery. Next, a second inner catheter is delivered to the internal
carotid artery past the site of the occlusion and the occlusive
device activated to occlude the internal carotid artery.
Alternatively, the first inner catheter can be positioned within
the internal carotid artery and the occlusive device activated,
followed by delivery of the second inner catheter to the external
carotid artery and activation of the occlusive device. In either
case, the occlusion is completely isolated between the three
occlusive devices. This is followed by therapy on the occlusion,
aspiration, and irrigation if desired, as described above.
[0151] F. Use of Occlusive Devices in Combination with
Perfusion
[0152] For some applications, it may be desirable to provide for
the perfusion of blood while medical procedures are performed on a
blood vessel such as the internal carotid artery. Several such
embodiments are now discussed in connection with FIGS. 29-32.
Perfusion may be necessary for those patients who can not tolerate
an excessive reduction of blood flow to their brain. One exemplary
method is illustrated in FIGS. 29A and 29B. FIG. 29A shows a
guidewire 420 to which an expandable member 470 is attached. In its
undeployed state, the expandable member 470 has a relatively narrow
profile so that the member 470 may be delivered through a blood
vessel. The expandable member 470 may be, for example, a mesh- or
filter-like device which, when deployed, permits the perfusion of
blood but is capable of entraining emboli. After positioning the
(undeployed) expandable member 470 distal to the lesion 410 within
the internal carotid artery 400 to be treated, the member 470 may
be deployed so that it expands to fill the internal carotid artery.
The expandable member 470 may be deployed by any one of a number of
techniques, for example, the distal end of the member 470 may be
attached to a pull wire (not shown) that passes through the
guidewire 420 such that when the pull wire is retracted, the member
470 expands to fill the internal carotid artery 400. (Conversely,
in this example, the member 470 may be returned to its undeployed
position when the pull wire moves in the distal direction.)
Alternatively, the member 470 may be self-expanding and deployed by
retracting a low profile sheath (not shown) that surrounds the
expandable member.
[0153] After the expandable member 470 is deployed, therapy may be
performed on the lesion 410, resulting in a treated lesion 410'. To
this end, a therapy catheter (not shown in FIGS. 29A and 29B) may
be deployed over the guidewire 420, and any one of a number of
therapy operations performed, such as balloon angioplasty,
deploying a stent, or the application of drug therapy. The therapy
catheter may then be withdrawn from the patient. Emboli that are
created as a result of the therapy are blocked by the expandable
member 470 when these emboli are flushed distally by anatomical
blood flow, so that the emboli are prevented from traveling
downstream towards the brain, for example. However, the expandable
member 470 still permits the perfusion of blood, so that the health
of tissue supported by the internal carotid artery 400 is not
jeopardized.
[0154] Following removal of the therapy catheter, an intermediate
catheter 474, to which an occlusive device 478 (such as an
occlusion balloon) is attached, is directed through the common
carotid 404 (by passing the catheter 474 over the guidewire 420 and
through a guide or main catheter 406) and positioned such that the
occlusive device 478 is distal to the treated lesion 410' and
proximal to (and preferably adjacent proximal to) the expandable
member 470. The occlusive device 478 may then be deployed to
occlude the internal carotid artery 400, thereby preventing
anatomical blood flow. Emboli that have been entrained within the
expandable member 470 may then be advantageously aspirated away by
applying suction through the intermediate catheter 474, such that
blood distal to the expandable member 470 passes through the
expandable member, entraining emboli in the process. The aspirated
emboli and blood pass through the intermediate catheter 474 and are
directed out of the patient. If the expandable member 470 is
clogged, aspiration will nevertheless draw emboli from the
expandable member by drawing blood from the proximal side of the
expandable member.
[0155] To remove any emboli that may be remaining in and around the
treated lesion 410', the main catheter 406 may be brought distal to
the treated lesion, as illustrated in FIG. 29B. With the occlusive
device 478 still deployed, irrigation fluid is ejected from an
opening near the distal end of the main catheter 406, such that
emboli are carried towards the intersection of the internal carotid
400 and the external carotid 402, whereupon the emboli are flushed
down the external carotid 402 by anatomical blood flow. The
expandable member 470 may be retracted, preferably while aspirating
through the intermediate catheter 474, so that any emboli that are
dislodged during the retraction of the expandable member are
removed from the patient. The expandable member 470, the
intermediate catheter 474, and the main catheter 404 may then be
removed from the patient.
[0156] Another embodiment in which an occlusive device is combined
with perfusion is illustrated in FIGS. 30A and 30B, in which the
expandable member 470 is positioned and deployed distal to the
lesion 410 as in the embodiment of FIG. 29A. After performing
therapy on the lesion 410, a catheter such as an outer catheter or
main catheter 490 is brought distal to the treated lesion 410'. An
occlusive device 482, such as a balloon, located on the main
catheter is then deployed, occluding the vessel 400. Aspiration is
then performed through the main catheter 490, so that blood flows
through the expandable member 470 and into the main catheter,
thereby removing emboli trapped in the expandable member, which may
have been produced as a result of therapy. If the expandable member
470 is clogged, aspiration will nevertheless draw emboli from the
expandable member by drawing blood from the proximal side of the
expandable member. Irrigation fluid may be advantageously ejected
from one or more openings 486 in the main catheter 490 distal to
the treated lesion 410', so that emboli remaining in and around the
treated lesion are flushed towards the intersection of the internal
carotid 400 and the external carotid 402, whereupon they are
flushed down the external carotid by anatomical blood flow. The
aspiration and irrigation steps may be performed sequentially or
simultaneously. While the expandable member 470 is retracted,
aspiration is preferably performed to remove any emboli that are
dislodged during the process of retracting the member 470.
[0157] FIG. 30B shows the cross section of the main catheter 490,
illustrating that the main catheter 490 of FIG. 30A has at least
three lumens--a lumen 492 for passing the guidewire 420 and the
therapy catheter (not shown in FIG. 30A), a lumen 494 for inflating
the occlusive device 482, and a lumen 496 for delivering irrigation
fluid to one or more openings 486 distal of the treated lesion
410'.
[0158] Yet another embodiment in which an occlusive device is
combined with perfusion is illustrated in FIG. 31, in which a
hypotube 502 having a plurality of holes 506 is passed through an
outer or main catheter 510. In the embodiment illustrated in FIG.
31, an occlusive device such as an occlusion balloon 514 is used
rather than the expandable member 470, and the hypotube 502 extends
beyond the occlusion balloon 514 in the distal direction to provide
perfusion while therapy is performed on a lesion 410.
[0159] After positioning the (uninflated) occlusion balloon 514
distal of the lesion 410 and positioning an opening 518 of the
hypotube 502 distal of the occlusion balloon 514, the occlusion
balloon is inflated so that the occlusion balloon occludes the
vessel 400 while contacting the hypotube 502. (The holes 506 in the
hypotube 502 are preferably located at least 1-2 mm proximal of the
lesion to reduce the risk of emboli entering the holes and
traveling distal of the occlusion balloon 514.) Therapy is then
performed on the lesion 410, while the inflated balloon 514 blocks
emboli (produced as a result of the therapy) from traveling
downstream. However, blood may still pass through the holes 506 in
the hypotube 502 and exit the opening 518 in the hypotube, so that
perfusion of blood is allowed. After the therapy is complete and
the therapy catheter is removed, a fluid port of the catheter 510
may be advantageously positioned distal to the treated occlusion
410' (and proximal to the balloon 514) and irrigation fluid
delivered distal to the treated lesion 410', so that fluid flows
across the treated occlusion in a distal to proximal direction. The
irrigation fluid carries away emboli towards the junction of the
internal carotid 400 and the external carotid 402, whereupon the
emboli are flushed down the external carotid by anatomical blood
flow. As an alternative (not shown) to using a hypotube dedicated
for perfusion, holes may be introduced into the guidewire, with the
guidewire having a lumen that extends through the occlusion balloon
leading to an opening distal of the balloon. The holes 506 in the
hypotube 502 or in the guidewire 420 may advantageously have
diameters of 0.005" or larger, or slits of dimensions
0.005".times.0.005". Several such hole (or slits) are preferably
used to create a flow of blood of between 8 and 50 cc/min.
[0160] The perfusion illustrated in FIG. 31 is passive, since the
blood passes through the hypotube 502 on its own. In the case of
active perfusion, a pump such as a syringe pump (not shown) may be
attached to the proximal end of a hypotube that does not have
holes. Alternatively, a guidewire such as guidewire 420 may be used
in which the guidewire passes through the occlusive device
422--such a guidewire has a lumen therein having an opening which
is distal to the balloon 514. The lumen could have a diameter
between 0.010" and 0.025", and more preferably a diameter of about
0.018". A preferred pump rate is between 8 and 40 cc/min.
[0161] Another embodiment that combines features of occlusion with
perfusion is illustrated in FIGS. 32A and 32B. The guidewire 420 is
brought through the vessel 400 until the expandable member 470 is
located distal to the lesion 410 to be treated. After deploying the
expandable member 470, therapy is performed on the lesion 410,
e.g., using a therapy catheter 550 to which an angioplasty balloon
560 is attached. During and after performing therapy on the lesion
410, the expandable member 470 collects emboli that may be produced
as a result of the therapy, as blood travels from one side of the
expandable member to the other in a proximal to distal direction.
After performing therapy (e.g., after deploying the angioplasty
balloon 560), the angioplasty balloon 560 is deflated and the
therapy catheter 550 is moved over the guidewire 420 in the distal
direction such that the angioplasty balloon 560 is distal of the
treated lesion 410'. The angioplasty balloon 560 is then reinflated
so that the vessel 400 is occluded. With the vessel 400 occluded, a
catheter 580 such as an outer or main catheter is then positioned
such that a fluid port of the catheter 580 is distal of the treated
lesion 410'. As illustrated in FIG. 32B, irrigation fluid is
ejected from the catheter 580 to flush away any emboli that may
remain in and around the treated lesion 410'. The irrigation fluid
and any emboli entrained within it travel in a distal to proximal
direction towards the intersection of the internal carotid 400 and
the external carotid 402, whereupon the irrigation fluid and emboli
are carried down the external carotid artery 402 by anatomical
blood flow. (Alternatively, the catheter 580 may be used to
aspirate the region in and around the treated lesion 410' to create
a flow of fluid in the proximal to distal direction.) The
expandable member 470, the therapy catheter 550, and the catheter
580 can then be removed from the patient. When removing the
expandable member 470 from the vessel 400, however, care should be
taken to avoid introducing any emboli into the bloodstream.
[0162] G. Accommodating Changes in Vessel Diameter
[0163] As a result of therapy being performed on a lesion, the
diameter of the vessel or vessels being occluded may increase. For
example, if the internal carotid artery is occluded distal to a
lesion within the carotid artery, and then treatment is performed
on that lesion, the diameter of the internal carotid artery may
increase substantially as a result of the treatment. If the
occlusive device in the internal carotid does not accommodate this
increase in diameter, resulting in a break in the seal between the
occlusive device and the walls of the internal carotid, the risks
to the patient may be significant.
[0164] A method for avoiding this possibility involves applying an
expansion force to the occlusive device beyond that which is
required to seal the occlusive device to the walls of the vessel.
For example, if an occlusion balloon is used as the occlusive
device in the internal carotid, then the balloon may be
advantageously inflated to a pressure beyond that which is required
to maintain a seal in the internal carotid. As the balloon begins
to be inflated, it will expand both axially and radially. The
balloon continues to expand radially until it mates with the walls
of the vessel, at which point further expansion of the balloon in
the radial direction is hindered by the tendency of the vessel to
resist enlargement. Continuing to inflate the balloon at this point
results in the balloon expanding preferentially in the axial
direction, rather than in the radial direction. As the balloon
expands in the axial direction, potential energy continues to be
stored up in the balloon.
[0165] If the vessel expands (e.g., as a result of therapy being
performed on it), then the potential energy stored in the balloon
is harnessed in that the balloon expands in the radial direction
(while correspondingly contracting somewhat in the axial
direction), such that the balloon continues to make contact with
the vessel during and following treatment, thereby preventing a
break in the seal which could result in injury to the patient.
Thus, with such a method, it is not necessary to actively adjust
the pressure in the balloon as a result of treatment of a lesion,
and in this sense, the seal is self-accommodating with respect to
changes in vessel diameter.
[0166] The occlusive device may also comprise a self-expanding
material such as nitinol, for which it is possible to obtain a
nearly constant level of stress over a relatively wide range of
strain. For example, if an occlusive device comprising a nitinol
filter-like mesh is capable of sealing a 6 mm diameter vessel, such
an occlusive device may be used to occlude a vessel that is
initially 5 mm in diameter, so that if the vessel expands, the
perfusion-filter will also expand to maintain occlusion within the
vessel.
[0167] The diameter of the internal carotid artery may increase
substantially as a result of therapy performed on it. For example,
a vessel that has a 4 mm diameter at the point where the occlusion
balloon is located may increase to 5 mm or more as a result of
therapy. Thus, in this method, the balloon may be advantageously
positioned in a blood vessel such that the vessel diameter is at
least 20% less than the maximum useful sealing diameter of the
balloon. As the lesion is treated, the balloon will continue to
seal against the walls of the vessel, even if the diameter of the
vessel should expand in response to the treatment. This method can
be used with a variety of expandable members other than balloons,
such as braids, coils, ribs, ribbon-like structures, slotted tubes,
and filter-like meshes, which may be partially or completely
covered with a membrane or another covering to provide a seal with
the vessel.
[0168] H. Inflation Apparatus
[0169] A preferred embodiment of a low volume or inflation syringe
60 in a syringe assembly 100 for inflating an occlusion balloon in
accordance with the present invention is shown in FIG. 33. Also
shown in FIG. 33 is an illustrative connection of the assembly 100
to an occlusion balloon guidewire catheter 62 (such as guidewire
420) utilizing an inflation adapter 30. The syringe assembly 100,
comprising the inflation syringe 60 and a larger capacity or
reservoir syringe 64, is attached via tubing 216 to the inflation
adapter 30 within which a sealing member 930 (see FIGS. 34A and
34B) and the balloon catheter 62 are engaged during use.
Alternatively, other devices that control the flow of inflation
fluid, such as flow controllers, may be used.
[0170] The sealing member 930, described in more detail below in
connection with FIGS. 34A and 34B, is inserted into an open
proximal end of the catheter 62. The syringe 60 is used to inject
inflation fluid through the adapter 30 and inflation port 17 into a
lumen of the catheter 62, and into a balloon 66 (such as balloon
422). The inflation adapter 30, described in more detail below in
connection with FIG. 35, is used to open and close the sealing
member 930 to permit the inflation or deflation of the balloon 66
mounted on the distal end of the catheter 62. However, it will be
emphasized that other types of adapters, valves, and/or sealing
members can be employed with the inflation syringe and/or syringe
assembly of the present inflation, in order to achieve rapid and
accurate inflation/deflation of medical balloons or other
nonballoon medical devices. Therefore, although illustrated in
connection with a low volume occlusion balloon 66, other types of
balloons and nonballoon devices may be utilized.
[0171] If the balloon 66 is mounted on the distal end of the
catheter 62, the syringe 60 and/or syringe assembly 100 is
preferably connected at the proximal end of the catheter 62. Prior
to use of the syringe 60 to inflate the balloon 66 to the proper
size for the vascular segment to be treated, the distal end of the
catheter 62 and the balloon 66 are first "primed" or evacuated. The
reservoir syringe 64 of the assembly 100 may be used for the
evacuation. Access to the vascular site is through a port in the
patient obtained, for example, using an introducer (not shown). A
preferred system and method for accomplishing the occlusion balloon
inflation is described below.
[0172] The inflation syringe 60 may be provided with a stop
mechanism 20 for limiting both the intake of fluid into the syringe
and the delivery of fluid from the syringe. The syringe 60 has an
elongate cylinder 44 and plunger arrangement 50 which provide for
greater displacement or travel by the plunger along the cylinder
length than is necessary to expel a relatively small amount of
inflation fluid. Thus, with the stop mechanism 20, the clinician is
provided with an enhanced sense of whether the fluid in the syringe
60 has been delivered to the balloon, which helps compensate for
lack of precision by the clinician. The stop mechanism 20 may be
mounted on the syringe 60 during production, or as separate
components that can be retro-fit onto an existing supply of
syringes.
[0173] Referring to FIGS. 33, 34A, 34B, and 35, the catheter 62 has
the sealing member 930 inserted into its proximal end and has a
side-access inflation port 17, shown in greater detail in FIGS. 34A
and 34B. The inflation port 17, proximal end of the catheter 62 and
distal end of the sealing member 930 are positioned within the
inflation adapter 30 (see FIG. 35) to which a syringe assembly 100
in accordance with the present invention has been operably coupled.
The inflation syringe 60 is coupled via an injection cap 22 at its
distal end to a valve 68 that also connects the large capacity
syringe 64 and a short tube segment 216. The tube segment 216 is
adapted to connect to a fitting or male luer member 24 of the
inflation adapter 30. Thus, the sealing member 930 is engaged by
the adapter 30 to allow use of the low volume syringe 60 of the
syringe assembly 100 to inflate the balloon 66 at the end of the
catheter 62.
[0174] The catheter 62 (depicted in FIGS. 34A and 34B) has a
proximal end 912, and a distal end (not shown in FIGS. 34A and 34B)
to which is mounted the inflatable balloon 66. A central lumen 940
extends within a tubular body 918 between the proximal and distal
ends. An opening 923 to lumen 940 is present at the proximal end
912 of catheter 62. The inflation port 17 in fluid communication
with lumen 940 is provided on tubular body 918.
[0175] The sealing member 930 is inserted into lumen 940 through
central lumen opening 923. Sealing member 930 has a first region
935 which has an outer diameter substantially the same as the outer
diameter of the proximal end 912 of the catheter tubular body.
Region 935 has a taper 934, reducing in diameter to a second region
933 which has an outer diameter less than the inner diameter of
lumen 940. In one embodiment, region 933 tapers over length 931 to
form a plug mandrel wire 932. As a consequence, region 933 and plug
mandrel wire 932 are slidably insertable into the proximal opening
923 of catheter 62 and may move within lumen 940. In one preferred
embodiment, region 935 has an outer diameter of about 0.013 inches,
region 933 has an outer diameter of about 0.008 inches, and plug
mandrel wire 932 has a diameter of about 0.006 inches, with region
933 and plug mandrel wire 932 being inserted into a catheter having
a central lumen 940 with an inner diameter of about 0.009
inches.
[0176] The length of sealing member region 935 extending proximally
of catheter 62 may vary in length depending upon the intended use
environment. For example, where catheter 62 is to be used as a
guide for other catheters in an "over-the-wire" embodiment, it is
preferred that the total length of catheter 62 and sealing member
region 935 be about 300 centimeters. Alternately, where catheter 62
is to be used in a single operator or rapid exchange embodiment, it
is preferred that the total length of catheter 62 and region 935 be
about 190 centimeters. Accordingly, with a known catheter length
and use environment, an appropriate length for region 935 may be
chosen.
[0177] Regions 935 and 933 and plug mandrel wire 932 may all be
made out of metals such as stainless steel. Alternatively,
combinations of materials may be used as well. For example, in some
applications it may be desirable to manufacture regions 935 and 933
out of stainless steel, while manufacturing plug mandrel wire 932
out of nitinol. Furthermore, the various sealing member regions may
be made from a single metal wire strand coined at various points to
achieve the desired dimensional tolerances, or multiple segments
may be joined together to form sealing member 930.
[0178] Where multiple segments are joined, region 935, region 933,
and plug mandrel wire 932 are attached to one another by any
suitable means of bonding metal to metal, such as crimping,
soldering, brazing, adhesives and the like. In one preferred
embodiment, cyanoacrylate adhesives are used to adhere these
various parts of sealing member 930 to one another.
[0179] As illustrated in FIGS. 34A and 34B, the outer diameter of
sealing member region 933 is less than the inner diameter of lumen
940, such that region 933 is slidably insertable into lumen 940. In
addition, the outer diameters of the tapered portions 931 and wire
932 are also small enough such that they too are slidably
insertable in lumen 940. However, the outer diameter of region 935
is greater than the inner diameter 940, and thus only a small
portion of tapered portion 934 of sealing member 930 between region
935 and region 933 is insertable into lumen 940 through opening
923. Advantageously, this provides for a snug interference fit when
sealing member 930 is fully inserted into catheter 62. This
interference fit provides a frictional force which counteracts the
tendency of the pressurized fluids and internal wire flexing in the
catheter to push sealing member 930 out of opening 923.
[0180] As illustrated in FIGS. 34A and 34B, sealing member 930 has
movement-force increasing structure which increases the force
required to move sealing member 930 within lumen 940. The
movement-force increasing structure consists of waves 938a and 938b
formed in wire 932 near its distal end. Waves 938a and 938b contact
the inner surface of lumen 940, thereby increasing the frictional
force which must be overcome to move wire 932 within lumen 940. In
one preferred embodiment, wire 932 is made of nitinol and has an
outer diameter of about 0.006 inches, and is inserted into a
nitinol catheter which has an inner lumen 940 with a diameter of
about 0.009 inches. In one embodiment, waves are formed on wire 932
for 3 cycles with an amplitude of about 0.019 inches to increase
the valve-opening movement force. Alternatively, by increasing the
length over which wire 932 contacts the inner wall of the tubular
body 918, the frictional forces may be increased.
[0181] A lumen sealer portion 936 is coaxially and fixedly mounted
on wire 932. Sealer portion 936 forms a fluid tight seal with the
outer diameter of wire 932 and the inner diameter of lumen 940,
such that fluid introduced into lumen 940 through the inflation
port 17 is prevented from flowing past sealer portion 936 when
sealer portion 936 is inserted into lumen 940 distally of the
inflation port 17. Sealer portion 936 forms the fluid tight seal by
firmly contacting the entire inner circumference of a section of
lumen 940 along a substantial portion of the length of sealer
portion 936.
[0182] As shown in FIG. 34A, sealer portion 936 is positioned
proximally of the inflation port 17, so that an unrestricted fluid
passageway exists between inflation port 17 and the inflatable
balloon at the distal end of catheter 62, which is like a valve
"open" position. In this position, region 933 is shown partially
withdrawn from opening 923. Referring to FIG. 34B, sealer portion
936 is positioned distally of inflation port 17, so that fluid flow
between inflation port 17 and the inflatable balloon 66 at the
distal end of catheter 62 are substantially blocked, which is like
a valve "closed" position.
[0183] Catheter 62 is changed from the valve open position to the
valve closed position by the movement of sealing member 930 and its
various components. Preferably, the exact length of movement needed
to change catheter 62 from the valve closed to the valve open
position is built into the movement function of the adaptor used to
manipulate sealing member 930 thereby opening and closing the
catheter valve. In this regard, it is preferred that catheter 62 be
used with an adaptor such as adaptor 30, which provides for such
controlled precise movement.
[0184] The "stroke-length", or overall movement in one dimension,
of sealing member 930 required to open or close the valve may be
varied depending upon the catheter requirements. When relying upon
the inflation adaptor to control movement, however, it is important
that the movement of the controlling elements of the adaptor be
coordinated with those of sealing member 930.
[0185] Referring to FIGS. 33 and 35, the inflation adapter 30
comprises a housing having two halves 34, 36 preferably formed of
metal, medical grade polycarbonate, or the like. In one embodiment,
the halves 34, 36 are attached by hinges 205 to be separated or
joined in a clam shell manner. A locking clip 38 secures the halves
while the adapter 30 is in use. A groove within the housing has a
width to accept the proximal end of the catheter 62 having the
sealing member 930. The male luer member 24 (FIG. 33), or other
suitable connector, extrudes from a top of the housing to provide
an inflation passageway. Seals 70 are provided within the housing
and around the internal segment 285 of the inflation pathway to
conduct the pressurized fluid provided by the syringe 60 attached
to the male luer member 24.
[0186] An actuator 40, shown in FIG. 33 at the top of the adapter
housing, controls a cam which operates sliding panels 291 (FIG. 35)
contained in the housing. Preferably, the catheter 62 is positioned
within the housing with the sealing member 930 in the closed
position (FIG. 34B), such that the side inflation port 17 is
located in the sealed inflation area 285 of the housing. An
adjacent proximal portion of the catheter 62 extends outside the
housing (and into the patient), and a proximal portion of the
sealing member 930 extends out of the other side of the housing.
The locking clip 38 is then secured and then the syringe 60 may be
attached. The actuator 40 is moved from a first position to a
second position, such that the sliding panels 291 within the
housing cause the sealing member 930 to be in an open position to
allow fluid flow through the inflation port 17 (FIG. 34A).
"Closing" the sealing member 930 is accomplished by moving the
actuator 40 from the second position back to the first position
(FIG. 34B), such that the balloon inflation is maintained.
[0187] Further details regarding catheter valves, catheter
balloons, and inflation adaptors are found in copending
applications Ser. No. 09/025,991 entitled "Syringe and Method for
Inflating Low Volume Catheter Balloons" filed Feb. 19, 1998, and
Ser. No. 08/975,723 entitled "Low Profile Catheter Valve and
Inflation Adaptor" filed Nov. 20, 1997, both of which are hereby
incorporated by reference herein.
[0188] While the foregoing detailed description has described
several embodiments of the apparatus and methods of the present
invention, it is to be understood that the above description is
illustrative only and not limiting of the disclosed invention. It
will be appreciated that the specific dimensions of the various
catheters and guidewires can differ from those described above, and
that the methods described can be used within any biological
conduit within the body and remain within the scope of the present
invention. Thus, the invention is to be limited only by the claims
which follow.
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