U.S. patent application number 11/159773 was filed with the patent office on 2005-11-03 for exchange method for emboli containment.
This patent application is currently assigned to Medtronic Vascular, Inc.. Invention is credited to Azizi, Gholam-Reza Zadno.
Application Number | 20050245866 11/159773 |
Document ID | / |
Family ID | 26700795 |
Filed Date | 2005-11-03 |
United States Patent
Application |
20050245866 |
Kind Code |
A1 |
Azizi, Gholam-Reza Zadno |
November 3, 2005 |
Exchange method for emboli containment
Abstract
The present invention provides a method for exchanging catheters
while containing emboli within a blood vessel such as a saphenous
vein graft, coronary artery, carotid artery, or other similar
vessels. A guidewire is inserted through the vasculature of a
patient until it reaches a desired treatment site. A therapy
catheter is then inserted over the guidewire until the distal end
of the therapy catheter reaches the treatment site. The guidewire
has a distally mounted balloon which is inflated to occlude the
blood vessel. Then, the therapy catheter provides means for
treating the vessel at the treatment site. After treatment, the
therapy catheter is removed from the guidewire and exchanged with
an aspiration catheter which rides over the guidewire until the
distal end of the aspiration catheter reaches the treatment site.
The aspiration catheter applies negative pressure to remove any
emboli formed by the treatment procedure.
Inventors: |
Azizi, Gholam-Reza Zadno;
(Newark, CA) |
Correspondence
Address: |
MEDTRONIC VASCULAR, INC.
IP LEGAL DEPARTMENT
3576 UNOCAL PLACE
SANTA ROSA
CA
95403
US
|
Assignee: |
Medtronic Vascular, Inc.
Santa Rose
CA
95403
|
Family ID: |
26700795 |
Appl. No.: |
11/159773 |
Filed: |
June 23, 2005 |
Related U.S. Patent Documents
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Application
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Filing Date |
Patent Number |
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11159773 |
Jun 23, 2005 |
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09768031 |
Jan 23, 2001 |
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09768031 |
Jan 23, 2001 |
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09049712 |
Mar 27, 1998 |
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6544276 |
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09049712 |
Mar 27, 1998 |
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08975723 |
Nov 20, 1997 |
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6050972 |
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08975723 |
Nov 20, 1997 |
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08812139 |
Mar 6, 1997 |
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08812139 |
Mar 6, 1997 |
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08650464 |
May 20, 1996 |
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09049712 |
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09026106 |
Feb 19, 1998 |
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6312407 |
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09026106 |
Feb 19, 1998 |
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08650464 |
May 20, 1996 |
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Current U.S.
Class: |
604/96.01 ;
606/194; 606/200 |
Current CPC
Class: |
A61M 25/0054 20130101;
A61B 17/12168 20130101; A61B 17/12172 20130101; A61F 2230/0006
20130101; A61M 25/10185 20131105; A61M 25/104 20130101; A61M
2025/1015 20130101; A61M 25/09 20130101; A61M 2025/1081 20130101;
A61M 2025/1079 20130101; A61F 2/013 20130101; A61M 2025/09008
20130101; A61B 17/12036 20130101; A61M 25/1011 20130101; A61B
17/12186 20130101; A61M 2025/1052 20130101; A61B 17/12113 20130101;
A61B 2017/320716 20130101; A61M 25/005 20130101; A61F 2/011
20200501; A61M 2025/1093 20130101; A61B 17/22 20130101; A61B
17/12022 20130101; A61M 2025/09116 20130101; A61M 2025/09175
20130101; A61F 2/0108 20200501; A61M 25/10 20130101; A61M 25/09033
20130101; A61B 17/12109 20130101; A61B 17/12136 20130101; A61M
25/0026 20130101; A61M 2025/0018 20130101; A61B 2017/22067
20130101; A61B 17/12181 20130101; A61M 2025/09125 20130101; A61M
25/0075 20130101; A61M 25/10184 20131105; A61M 25/0009 20130101;
A61M 25/1027 20130101 |
Class at
Publication: |
604/096.01 ;
606/194; 606/200 |
International
Class: |
A61M 029/00 |
Claims
1-28. (canceled)
29. A catheter system for emboli containment, comprising: a
guidewire having a proximal end and a distal end; an occlusive
device connected to the distal end of the guidewire, the occlusive
device being actuatable between an expanded state in which the
occlusive device engages at least a portion of the walls of a blood
vessel, and a nonexpanded state in which the occlusive device does
not engage the walls of the blood vessel; a first treatment
catheter having a proximal end and a distal end and a lumen
extending therethrough; and a second treatment catheter having a
proximal end and a distal end and a lumen extending therethrough;
wherein the first treatment catheter is adapted to be delivered
over and then removed from the guidewire, and the second treatment
catheter is adapted to be delivered over and then removed from the
guidewire following removal of the first treatment catheter, and
wherein the occlusive device is capable of maintaining its expanded
state while the first treatment catheter is removed from the
guidewire and while the second treatment catheter is delivered over
the guidewire.
30. The catheter system of claim 29, wherein the first treatment
catheter is a therapy catheter.
31. The catheter system of claim 29, wherein the second treatment
catheter is a therapy catheter.
32. The catheter system of claim 29, wherein the second treatment
catheter is an aspiration catheter.
33. The catheter system of claim 30, wherein the second treatment
catheter is an aspiration catheter.
34. The catheter system of claim 29, further comprising a third
treatment catheter having a proximal end and a distal end and a
lumen extending therethrough, wherein the third treatment catheter
is adapted to be delivered over and then removed from the guidewire
following removal of the first treatment catheter and prior to
delivery of the second treatment catheter.
35. The catheter system of claim 34, wherein the first treatment
catheter has a dilatation balloon of a first diameter on its distal
end, the third treatment catheter has a dilatation balloon of a
second diameter on its distal end, the second diameter being larger
than the first diameter, and the second treatment catheter is an
aspiration catheter.
36. The catheter system of claim 29, wherein the guidewire includes
a lumen extending therethrough.
37. The catheter system of claim 36, wherein the occlusive device
is an inflatable balloon.
38. The catheter system of claim 37, further comprising a valve
within the lumen of the guidewire for maintaining the occlusive
device in either its expanded or nonexpanded state.
39. A catheter system for emboli containment, comprising: a
guidewire having a proximal end and a distal end; an occlusive
device connected to the distal end of the guidewire, the occlusive
device being actuatable between an expanded state in which the
occlusive device engages at least a portion of the walls of a blood
vessel, and a nonexpanded state in which the occlusive device does
not engage the walls of the blood vessel; and a catheter having a
proximal end and a distal end and a lumen extending therethrough,
the catheter being adapted to be delivered over and removed from
the guidewire; wherein the occlusive device is capable of
maintaining its expanded state while the catheter is either
advanced over or removed from the guidewire.
40. The catheter system of claim 39, wherein the occlusive device
can be actuated from its nonexpanded state to its expanded state
while the catheter is positioned over the guidewire.
41. The catheter system of claim 39, wherein the occlusive device
can be deactuated from its expanded state to its nonexpanded state
while the catheter is positioned over the guidewire.
42. The catheter system of claim 39, wherein the catheter is a
therapy catheter.
43. The catheter system of claim 39, wherein the catheter is an
aspiration catheter.
44. The catheter system of claim 39, wherein the guidewire includes
a lumen extending therethrough.
45. The catheter system of claim 44, wherein the occlusive device
is an inflatable balloon.
46. The catheter system of claim 45, further comprising a valve
within the lumen of the guidewire for maintaining the occlusive
device in either its expanded or nonexpanded state.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application
Ser. No. ______, entitled LOW PROFILE CATHETER VALVE AND INFLATION
ADAPTOR, filed Nov. 20, 1997 (Attorney Docket No. PERCUS.006CP1),
the entirety of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to medical catheters used in
treating saphenous vein grafts, coronary arteries, and other blood
vessels, and more particularly, to a method for exchanging
catheters during emboli containment in such vessels.
[0004] 2. Description of the Related Art
[0005] Guidewires are conventionally used to guide the insertion of
various medical instruments, such as catheters, to a desired
treatment location within a patient's vasculature. In a typical
procedure, the clinician forms an access point for the guidewire by
creating an opening in a peripheral blood vessel, such as the
femoral artery. The highly flexible guidewire is then introduced
through the opening into the peripheral blood vessel, and is then
advanced by the clinician through the patient's blood vessels until
the guidewire extends across the vessel segment to be treated.
Various treatment catheters, such as a balloon dilatation catheter
for a percutaneous transluminal coronary angioplasty, may then be
inserted over the guidewire and similarly advanced through
vasculature until they reach the treatment site.
[0006] In certain treatment procedures, it is desirable to
successively introduce and then remove a number of different
treatment catheters over a guidewire that has been placed in a
particular location. In other words, one treatment catheter is
"exchanged" for another over a single guidewire. Such an exchange
typically involves withdrawing the treatment catheter over the
guidewire until the treatment catheter is fully removed from the
patient and the portion of the guidewire which extends from the
patient. The guidewire is then available to act as a guide for a
different treatment catheter.
[0007] As can be readily appreciated, the withdrawal of treatment
catheters over a placed guidewire may result in the guidewire being
displaced from its position. To overcome this difficulty, the prior
art has developed "anchorable" guidewires, which generally feature
some structure on their distal ends to releasably secure the
guidewire at a particular location in the patient for the duration
of the medical procedure. One such anchorable guidewire is
disclosed in U.S. Pat. No. 5,167,239 to Cohen et al., which
discloses a hollow guidewire with an inflation, lumen and an
expandable balloon on its end. The Cohen device includes a
removable inflation manifold, and a check valve to maintain the
balloon in the inflated state when the manifold is removed. The
check valve apparatus used by the Cohen device is relatively bulky,
and is described as having an outer diameter in its preferred
embodiment of 0.0355 inches. Consequently, any treatment catheter
intended to be inserted over the Cohen device must have an interior
guidewire lumen larger than the outer diameter of the Cohen valve,
which for the preferred embodiment, requires an interior lumen with
a diameter of more than 0.0355 inches. Cohen also does not address
the problem of emboli containment.
[0008] As is readily appreciated by those of skill in the art,
increasing the interior lumen size of a treatment catheter results
in an increase in the outer diameter of the treatment catheter.
However, many blood vessels where it is desirable to apply catheter
treatment are quite narrow. For example, the left coronary arteries
are blood vessels having diameters ranging from 2 to 4 mm, and are
susceptible to plaque. Similarly, saphenous vein grafts (SVG) and
the carotid arteries are also quite small and susceptible to
plaque, and could not practically be treated by larger diameter
devices.
[0009] Human blood vessels often become occluded or completely
blocked by plaque, thrombi, other deposits, emboli 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.
[0010] Coronary heart disease is an extremely common disorder in
developed countries, and is the leading cause of death in the U.S.
Damage to or malfunction of the heart is caused by narrowing or
blockage of the coronary arteries (atherosclerosis) that supply
blood to the heart. The coronary arteries are first narrowed and
may eventually be completely blocked by plaque, and may further be
complicated by the formation of thrombi (blood clots) on the
roughened surfaces of the plaques. Myocardial infarction can result
from atherosclerosis, especially from an occlusive or near
occlusive thrombi overlying or adjacent to the atherosclerotic
plaque, leading to death of portions of the heart muscle. Thrombi
and emboli also often result from myocardial infarction, and these
clots can block the coronary arteries, or can migrate further
downstream, causing additional complications.
[0011] 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
balloon angioplasty. A balloon catheter is inserted into the
narrowed or blocked area, and the balloon is inflated to expand the
constricted area. In many cases, near normal blood flow is
restored. It can be difficult, however, to treat plaque deposits
and thrombi in the coronary arteries, because the coronary arteries
are small, which makes accessing them with commonly used catheters
difficult.
[0012] Other types of intervention include atherectomy, deployment
of stents, introduction of specific medication by infusion, and
bypass surgery. Each of these methods are not without the risk of
embolism caused by the dislodgement of the blocking material which
then moves downstream. In addition, the size of the blocked vessel
may limit percutaneous access to the vessel.
[0013] In coronary bypass surgery, a more costly and invasive form
of intervention, a section of a vein, usually the saphenous vein
taken from the leg, is used to form a connection between the aorta
and the coronary artery distal to the obstruction. Over time,
however, the saphenous vein graft may itself become diseased,
stenosed, or occluded, similar to the bypassed vessel.
Atherosclerotic plaque in saphenous vein grafts tends to be more
friable and less fibrocalcific than its counterpart in native
coronary arteries.
[0014] Diffusely diseased old saphenous vein grafts with friable
atherosclerotic lesions and thrombi have therefore been associated
with iatrogenic distal embolic debris. Balloon dilatation of
saphenous vein grafts is more likely to produce symptomatic
embolization than dilatation of the coronary arteries, not only
because of the difference in the plaque but also because vein
grafts and their atheromatous plaques are generally larger than the
coronary arteries to which they are anastomosed. Once the plaque
and thrombi are dislodged from the vein, they can move downstream,
completely blocking another portion of the coronary artery and
causing myocardial infarction. In fact, coronary embolization as a
complication of balloon angioplasty of saphenous vein grafts is
higher than that in balloon angioplasty of native coronary
arteries. Therefore, balloon angioplasty of vein grafts is
performed with the realization that involvement by friable
atherosclerosis is likely and that atheroembolization represents a
significant risk.
[0015] Because of these complications and high recurrence rates,
old diffusely diseased saphenous vein grafts have been considered
contraindications for angioplasty and atherectomy, severely
limiting the options for minimally invasive treatment. However,
some diffusely diseased or occluded saphenous vein grafts may be
associated with acute ischemic syndromes, necessitating some form
of intervention.
[0016] Furthermore, attempts heretofore have been made to treat
occlusions in the carotid arteries leading to the brain. However,
such arteries have been very difficult to treat because of the
possibility of dislodging plaque which can enter various arterial
vessels of the brain and cause permanent brain damage. Attempts to
treat such occlusions with balloon angioplasty have been very
limited because of such dangers. In surgical treatments, such as
endarterectomy, the carotid artery is slit and plaque is removed
from the vessel in the slit area. Such surgical procedures have
substantial risk associated with them which can lead to morbidity
and mortality.
[0017] In other procedures, such as in angioplasty and in the
treatment of peripheral arteries and veins, there is the
possibility that the guide wires and catheters used in such
procedures during deployment of the same may cause dislodgement of
debris or emboli which can flow downstream and cause serious
damage, such as stroke, if they occlude blood flow in smaller
vessels. Moreover, when treating aneurysms, coils or other objects
deployed to fill the aneurysm may break free and become lost
downstream. Thus, in summary, embolization and migration of
micro-emboli downstream to an end organ is a major concern of
cardiologists during catheterizations.
[0018] Accordingly, what is needed is an exchange method for use
during treatment of narrow blood vessels such as the carotid
arteries, coronary arteries and saphenous vein grafts.
Specifically, what is needed is a method which allows an exchange
of catheters while a distal occluding device is deployed to perform
treatment within the vessel and to contain emboli produced,
created, or used during the treatment procedure. Furthermore,
because a distal occluding device may block the flow of blood to
vital organs, it is desirable that the exchange be performed
quickly and easily in order to minimize the time that the blood
vessel is occluded.
SUMMARY OF THE INVENTION
[0019] The present invention satisfies the above needs by providing
a method for exchanging catheters during an emboli containment
procedure. As described herein, the term "emboli" may refer to any
debris, particles, or other objects found, created or placed in a
blood vessel. "Emboli containment" may refer to emboli removal,
neutralization, disintegration, minimization, or simply to
preventing emboli from moving downstream. In essence, "containment"
refers to any procedure which reduces the deleterious effects that
emboli may have on the patient. The preferred exchange method is
particularly useful in angioplasty and similar procedures in
smaller blood vessels such as the coronary or carotid arteries or
in saphenous vein grafts. The exchange method described herein can
be accomplished rapidly to minimize the time that a treated blood
vessel is occluded for treatment.
[0020] For example, in most angioplasty procedures, a guidewire is
first introduced into the vasculature of a patient until the distal
end of the guidewire is near the occlusion or stenosis. The
guidewire preferably bears a distal occlusion device, such as a
balloon, filter, coil, or combination of these elements. The
occlusive device is preferably activated prior to performing
therapy to remove or reduce an occlusion or stenosis, to provide a
working area and to prevent particles and debris produced during
therapy from migrating downstream. The occlusive device may
completely or partially occlude the vessel.
[0021] In order to perform an exchange over the guidewire catheter,
the catheter must be made such that the occlusive device remains
activated in order to minimize particles from going downstream.
Furthermore, the proximal end of the guidewire must have a low
profile to accommodate other catheters which are to be advanced
over the guidewire. In one preferred method, a therapy catheter is
advanced over a proximal end of the guidewire to the site of the
plaque or lesion. After deploying the occlusive device on the end
of the guidewire, therapy is performed on the lesion by the therapy
device. One preferred therapy device is a dilatation catheter which
compresses the lesion against the walls of the vasculature. In
addition to dilatation balloon catheters, other forms of therapy
may be used to dislodge, disintegrate, or neutralize the plaque.
One method is to provide an ultrasonic catheter which targets the
plaque and destroys it using shock waves. Another method is to use
a vibration delivery catheter, which causes the plaque to break up
due to a vibrating wire. Another method uses a drug delivery
catheter provided over the guidewire, which provides fluids to
dissolve the plaque. Other types of therapy include radiation
therapy.
[0022] After treatment of the plaque by an appropriate therapy
method, emboli often remain in the working area. The therapy
catheter can then be removed and exchanged with an emboli removal
catheter, such as an aspiration catheter for aspirating the emboli
from the working area. The aspiration catheter can then be
exchanged with another therapy catheter, such as a catheter bearing
a stent which is deployed onto the lesion for maintaining the
opening of the blood vessel.
[0023] The present invention in a preferred embodiment allows for
the rapid and easy exchange of catheters by deploying the occlusive
device in stages. For instance, when a guidewire with a distal
occlusion balloon is used, the balloon is inflated only when there
is danger of emboli moving downstream. Thus, if treatment of the
stenosis consists of a dilatation procedure and deployment of a
stent, the occlusion balloon will be inflated for a first inflation
period during which the dilatation balloon works on the plaque, the
dilatation catheter is exchanged with an aspiration catheter, and
the aspiration catheter removes emboli from the vessel. After
aspiration, the occlusion balloon can safely be deflated to allow
blood flow for a period to organs downstream. An exchange can then
be performed with another therapy catheter, such as a stent
deploying catheter, and the occlusion balloon is reinflated for a
second inflation period to deploy a stent to the location of the
stenosis. By employing an exchange method with vessel occlusion
occurring in stages, the time that blood flow is occluded in the
vessel decreases, thereby minimizing the risks to the patient and
presenting significant advantages over known technology. The speed
of exchange is also improved by using an adaptor which allows for
easy and quick handling of the guidewire for inflation and
deflation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1A is a schematic view of a patient undergoing
treatment by a preferred aspect of the exchange method of the
present invention.
[0025] FIG. 1B is a perspective view of a human heart with a
saphenous vein graft.
[0026] FIG. 2 is an enlarged perspective view of the proximal end
of the guidewire shown in FIG. 1A, particularly showing an exchange
method between a therapy catheter and an aspiration catheter.
[0027] FIGS. 3A is a perspective view of an over-the-wire therapy
catheter having a dilatation balloon on its distal end and
guidewire inserted into a saphenous vein graft in accordance with a
preferred aspect of the present invention, with the vein graft
shown partially cut away.
[0028] FIG. 3B is a perspective view of a guidewire inserted into a
saphenous vein graft after the therapy catheter of FIG. 3A has been
removed, with the vein graft shown partially cut away.
[0029] FIG. 3C is a perspective view of an over-the-wire aspiration
catheter and a guidewire inserted into a saphenous vein graft after
an exchange with the therapy catheter of FIG. 3A has been
performed, with the vein graft shown partially cut away.
[0030] FIG. 3D is a perspective view of an over-the-wire stenting
balloon and a guidewire inserted into a saphenous vein graft after
an exchange with the aspiration catheter of FIG. 3C has been
performed, with the vein graft shown partially cut away.
[0031] FIG. 4 is a side view of a guidewire inserted into a
saphenous vein graft, the guidewire having a radiopaque marker for
targeting by an external shock wave generator, with the vein graft
shown partially cut away.
[0032] FIG. 5 is a side view of a vibration delivery catheter and a
guidewire inserted into a saphenous vein graft, with the vein graft
shown partially cut away.
[0033] FIG. 6 is a side view of a drug delivery catheter and a
guidewire inserted into a saphenous vein graft, with the vein graft
shown partially cut away.
[0034] FIG. 7 is a side view of an aspiration catheter and a
guidewire inserted into an artery being treated for an aneurysm,
with the artery shown partially cut away.
[0035] FIG. 8 is a chart showing the inflation times of a distal
occlusion balloon for 24 patients being treated in a preferred
aspect of the exchange method of the present invention.
[0036] FIG. 9 is a side view of a catheter incorporating the low
profile valve in a preferred aspect of the present invention.
[0037] FIG. 10 is an enlarged view of the proximal portion of the
catheter of FIG. 10 showing an exterior view of the catheter
segment featuring the low profile valve in a preferred aspect of
the present invention.
[0038] FIG. 11A is a longitudinal cross-sectional view of the
catheter segment of FIG. 10 showing the low profile valve in the
open position.
[0039] FIG. 11B is a longitudinal cross-sectional view of the
catheter segment of FIG. 10 showing the low profile valve in the
closed position.
[0040] FIG. 12 is a longitudinal cross-sectional view of an
alternative embodiment, showing the low profile valve in the closed
position.
[0041] FIG. 13 is a longitudinal cross-sectional view of the
embodiment of FIG. 12 showing the low profile valve in the open
position.
[0042] FIG. 14 is a longitudinal cross-sectional view of an
alternative embodiment of the low profile valve, depicting the
valve in the open position
[0043] FIG. 15 is a longitudinal cross-sectional view of the
embodiment of FIG. 14 depicting the valve in the closed
position.
[0044] FIG. 16 is a perspective view of an inflation adaptor used
to manipulate the low profile valve in a preferred aspect of the
present invention.
[0045] FIG. 17A is a perspective view of the interior of the
inflation adaptor of FIG. 16.
[0046] FIG. 17B is a perspective view of a catheter with a sealing
member and alignment indicia being positioned in the inflation
adaptor of FIG. 17A.
[0047] FIG. 17C is a perspective, view of an inflation adaptor
attached to a syringe system.
[0048] FIG. 17D is a side view of an aspiration catheter attached
to a syringe system.
[0049] FIG. 18 is an end view of an alternative embodiment of the
inflation adaptor.
[0050] FIG. 19 is a cross-sectional view of the inflation adaptor
of FIG. 18 along lines 19-19.
[0051] FIGS. 20 and 21 are exploded views of alternative
embodiments of the low profile valve in a preferred aspect of the
present invention.
[0052] FIG. 22 is an alternative embodiment of the valve in a
preferred aspect of the present invention featuring a built in
spring bias.
[0053] FIGS. 23A and 23B are longitudinal cross-sectional views of
the catheter proximal end of FIG. 22 showing the valve in the
closed and open position, respectively.
[0054] FIG. 24 is a perspective view of an alternative embodiment
of an inflation adaptor used to manipulate the low profile valve in
a preferred aspect of the present invention.
[0055] FIG. 25 is a perspective view of the interior of the
inflation adaptor of FIG. 24.
[0056] FIGS. 26A and 26B are top views of the inflation adaptor of
FIGS. 24 and 25, illustrating the latch locking mechanism.
[0057] FIGS. 27A-27C are schematic cross-sectional views of the
adaptor of FIG. 24 which illustrate the cam locking door mechanism
which provides mechanical advantage to the adaptor locking
latch.
[0058] FIGS. 28A-28C are close-up views of an embodiment of the
adaptor having a sliding top panel biased by a spring
mechanism.
[0059] FIGS. 29 and 30 are cross-sectional views of a proximal
section of a catheter having an alternative embodiment of the valve
in a preferred aspect of the present invention.
[0060] FIG. 31 is a side-elevational view in section of one
embodiment of a catheter apparatus incorporating a preferred aspect
of the present invention for treating occluded vessels.
[0061] FIG. 32 is a side-elevational view in section similar to
FIG. 31 but showing the apparatus in FIG. 31 with the expansion
member (in this case, a self-expandable seal) deployed.
[0062] FIG. 33 is a side-elevational view in section of another
embodiment of a catheter apparatus incorporating a preferred aspect
of the present invention for treating occluded vessels.
[0063] FIG. 34 is a view similar to FIG. 33 but showing the
expansion member (in this case, a self-expandable seal)
deployed.
[0064] FIG. 35 is a side-elevational view in section of another
embodiment of a catheter apparatus incorporating a preferred aspect
of the present invention for treating occluded vessels.
[0065] FIG. 36 is a view similar to FIG. 35 but showing the
expansion member deployed and the sleeve completely removed.
[0066] FIG. 37 is a schematic, longitudinal cross sectional view of
an embodiment in which a membrane only partially surrounds a braid
used as the expansion member.
[0067] FIGS. 38A and 38B show end views of unperforated and
perforated membranes, respectively.
[0068] FIG. 39 is a schematic, longitudinal cross sectional view of
an embodiment in which a braid without a membrane is used.
[0069] FIG. 40 is a schematic, longitudinal cross sectional view of
an embodiment in which a filter-like mesh is used as the expansion
member.
[0070] FIG. 41 is a schematic, longitudinal cross sectional view of
an embodiment in which a slotted tube is used as the expansion
member.
[0071] FIG. 42 is a perspective view of the slotted tube used in
the embodiment of FIG. 41.
[0072] FIG. 43 is a schematic, longitudinal cross sectional view of
an embodiment in which a coil is used as the expansion member, and
the proximal end of a membrane surrounding the coil adjoins the
coil.
[0073] FIG. 44 is a schematic, longitudinal cross sectional view of
an embodiment in which a coil is used as the expansion member, and
the proximal end of a membrane surrounding the coil adjoins a
sheath that surrounds both first and second elongate members.
[0074] FIG. 44A is an embodiment similar to that shown in FIG. 44
in which resistive heating is used to expand the expansion member,
with current being conducted through wires being attached to either
side of the expansion member. The expansion member as shown is
partially deployed.
[0075] FIG. 44B is an embodiment similar to that shown in FIG. 44A
in which resistive heating is used to expand the expansion member,
with current being conducted through a wire being attached to the
distal end of the expansion member and through a coating on the
first elongate member. The expansion member as shown is partially
deployed.
[0076] FIG. 45 is a schematic, side cross sectional view of an
embodiment in which a plurality of ribbons are used as the
expansion member.
[0077] FIG. 45A is an embodiment similar to that shown in FIG. 45
in which a warm solution passes between the first and second
elongate members to transfer heat to the expansion member, causing
it to expand. The expansion member as shown is partially
deployed.
[0078] FIG. 45B is an embodiment similar to that shown in FIG. 45A
in which a warm solution passes through the first elongate member
to transfer heat to the expansion member, causing it to expand. The
expansion member as shown is partially deployed.
[0079] FIG. 45C is an embodiment similar to that shown in FIGS. 45A
and 45B, in which a warm solution passes through one or more lumens
in the first elongate member to transfer heat to the expansion
member, causing it to expand. The expansion member as shown is
partially deployed.
[0080] FIG. 46 is a schematic, side cross sectional view of an
embodiment in which a plurality of ribs are used as the expansion
member.
[0081] FIG. 47 is an isometric view of an embodiment of the
invention in which a pull wire is used to deploy a plurality of
non-self-expanding ribbons surrounded by a membrane.
[0082] FIG. 48 is a side partial sectional view of the embodiment
of FIG. 43 in which the ribbons are in their relaxed, undeployed
position.
[0083] FIG. 49 is a side elevational view of the embodiment of FIG.
47 in which the ribbons are deployed, and the membrane makes a seal
with the vessel.
[0084] FIGS. 50A and 50B show longitudinal and end perspective
views, respectively, of a locking mechanism used with a wire that
deploys an expansion member.
[0085] FIG. 50C is a perspective view of the locking mechanism of
FIGS. 50A and 50B, further showing an adaptor for utilizing the
locking mechanism.
[0086] FIG. 51A is a perspective view of an alternative locking
mechanism used with a wire that deploys an expansion member.
[0087] FIG. 51B is a perspective view of the alternative locking
mechanism of FIG. 51A, further showing an adaptor for utilizing the
locking mechanism.
[0088] FIGS. 52A, 52B, 52C, and 52D show, respectively, a braid, a
filter-like mesh, a slotted tube, and a plurality of coils, which
can be used as alternative expansion members in place of the
ribbons in the embodiment of FIG. 47.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0089] I. Exchange Method During Emboli Containment
[0090] The method discussed herein allows for the rapid exchange of
catheters during angioplasty and similar procedures. In particular,
the preferred method of the present invention is adapted for use in
the treatment and removal of an occlusion in a blood vessel in
which the occlusion has a length and a width or thickness which at
least partially occludes the vessel's lumen. Thus, the catheters of
a preferred aspect of the present invention are effective in
treating both partial and complete occlusions of the blood vessels.
As used herein, "occlusion" includes both partial and complete
occlusions, stenoses, emboli, thrombi, plaque and any other
substance which at least partially occludes the vessel's lumen.
[0091] The method and apparatus of the present invention preferably
can be used in any vessel of the body where the pressure is at
least 0.2 psi at any stage of the heart pumping cycle, and more
preferably, is about 1.2 psi, with a flow rate of at least 10 cc
per minute. The method and apparatus are particularly suited for
use in removal of occlusions from saphenous vein grafts, coronary
and carotid arteries, and in other non-branching vessels having
similar pressures and flow where a suitable working area can be
created. Although the present invention will be described in
connection with a saphenous vein graft, it should be understood
that this application is merely exemplary, and the method can be
used in other blood vessels as well. For example, it will be
appreciated that the described method can also be applied to
coronary arteries, carotid arteries, or any other arteries or veins
where treatment and containment of emboli is desired.
[0092] A. The Preferred Treatment Method
[0093] In one preferred aspect of the present invention, a catheter
or guidewire 10 is inserted into the human body 1 through a groin
insertion site 3, as shown in FIG. 1A. The guidewire 10 is passed
through the femoral artery 5 and into the blood vessel network
until it reaches the intended treatment site, which, as shown in
FIG. 1B, is a saphenous vein graft 2. The graft 2 is used to bypass
one of the occluded coronary arteries 4, and connects the aorta 6
to the coronary artery at a location distal the occlusion 8.
Fluoroscopy is typically used to guide the guidewire 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.
[0094] The catheter 10 used for the preferred method is shown in
FIGS. 9-11B. As described in further detail below, the catheter 10
comprises a tubular body 18 having a central lumen 40 extending
between a proximal end 12 and a distal end 14. An inflation port 22
is provided near the proximal end 12 of the tubular body, which
allows inflation fluid to pass through central lumen 40 to a
distally mounted occlusive device, such as a balloon 20. A sealing
member 30 is inserted to the lumen 40 at opening 23 of the tubular
body. This sealing member extends into the lumen 40 and plugs the
inflation port 22 to maintain balloon inflation, as described in
more detail with respect to FIGS. 11A and 11B below.
[0095] FIG. 2 shows an enlarged view of the proximal end of the
guidewire 10 with sealing member 30 inserted therein. Both the
guidewire 10 and the sealing member 30 have substantially the same
diameter, thereby allowing a catheter or guidewire having at least
one inner lumen to pass over the two. This inner lumen can be made
small to have substantially the same diameter as the outer diameter
of the guidewire and sealing member. In the preferred embodiment,
the outer diameter of the tubular body 18 and the sealing member 30
is about 0.014 inches. Therefore, catheters having a lumen with a
diameter as small as 0.014 inches may be exchanged over the
guidewire 10.
[0096] FIG. 2 also illustrates an exemplary exchange method. Where
guidewire 10 carries a first treatment catheter such as a therapy
catheter 50 having a dilatation balloon 52, this therapy catheter
50 can be slid off the proximal end of the guidewire 10 and sealing
member 30. Then, a second treatment catheter such as an aspiration
catheter 60 may be slid over the proximal ends of the sealing
member 30 and the guidewire 10 toward the treatment location.
Further details regarding this exchange are described below.
[0097] 1. Insertion of the Guidewire
[0098] FIGS. 3A-3D show more explicitly a preferred method of
containing and aspirating embolic material while performing a
balloon angioplasty and stenting therapy. FIG. 3A shows a lesion or
plaque 42 on the walls of a saphenous vein graft 2. A catheter or
guidewire 10 is advanced into the blood vessel to a point distal of
the lesion 42. The method of a preferred aspect of the present
invention can effectively be carried out using 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. As described in further detail
below, the catheter has an occlusive device, such as an inflatable
balloon, filter or other mechanical occlusive device, attached at
its distal end. 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. Substantial
occlusion of the vessel can be sufficient for purposes of the
present invention.
[0099] The guidewire 10 should be sized so as to be slidable with
respect to the therapy, aspiration or other catheters to be
inserted over the guidewire. When the guidewire is properly
positioned inside the vessel, the occlusive device at the distal
end of the guidewire is actuated to occlude the vessel distal to
the existing lesion to create a working area. With the occlusive
device effectively blocking the flow of emboli downstream, various
catheters may be exchanged over the guidewire 10 to treat the
vessel without the risk of emboli flowing downstream and cutting
off blood flow to vital organs.
[0100] In non-bifurcated areas of the blood vessels, it has been
discovered that fluid from the proximal portion of the same vessel
acts as an infusion source. One therefore need only occlude the
distal portion of the vessel to create a working area surrounding
the occlusion and allow blood to flow from the proximal portion of
the vessel into the working area. 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. Thus, the embodiment described above only provides
an occlusive device distal to the working area.
[0101] However, an embodiment is also contemplated wherein the
working area is defined by occlusive devices located both proximal
and distal to the lesion 42. In this embodiment, a guide catheter
having a single lumen is first introduced into the patient's
vasculature through an incision made in the femoral artery or vein
in the groin and used to guide the insertion of other catheters and
devices to the desired site. This guide catheter carries an
occlusion balloon or other occlusive device to occlude the vessel
proximal to the lesion 42. Following insertion of the guide
catheter, a second catheter is inserted through the guide catheter
and past the site of the occlusion. This second catheter serves as
the exchange catheter or guidewire over which various catheters may
be advanced and removed.
[0102] 2. Therapy Catheter/Aspiration Catheter Exchange
[0103] As shown in FIG. 3A, once the guidewire 10 is in place, a
therapy catheter may then be delivered to the site of the
occlusion. The therapy catheter can employ any number of means for
treatment, including a balloon catheter used to perform
angioplasty, a catheter which delivers a stent, a catheter for
delivering enzymes, chemicals, or drugs to dissolve or treat the
occlusion, an atherectomy device, or a laser or ultrasound device
used to ablate the occlusion.
[0104] The therapy catheter 50 of the preferred embodiment includes
a dilatation balloon 52 located on the distal end of an elongate
tubular body 54. The tubular body 54 has a lumen 56 extending from
a proximal end to the distal end of the tubular body which is sized
to override the guidewire 10 until the dilatation balloon 52
reaches the point of the lesion 42. Once balloon 52 is in place,
the occlusion balloon 20 on guidewire 10 is inflated to at least
partially block blood flow. Then, the dilatation balloon 52 is
inflated to compress the plaque 42 against the walls of the blood
vessel. This inflation has the effect of dislodging some plaque and
creating emboli 48 (shown, in FIG. 3B) in the working area.
[0105] In the preferred method, after treatment by the therapy
catheter 50 is completed, the therapy catheter is completely
removed from the body by sliding the therapy catheter over the
guidewire 10 in a proximal direction away from the lesion and out
of the body, leaving only the guidewire 10 as shown in FIG. 3B. A
rapid exchange is then performed and, as illustrated in FIG. 3C, an
aspiration catheter 60 is deployed over the guidewire 10. The term
"aspiration catheter" includes any device which creates an area of
fluid turbulence and uses negative pressure and reverse flow to
aspirate fluid and debris, and includes those devices which create
a venturi effect within the vessel. Aspiration catheter 60 as shown
in FIG. 3C is an elongate tubular body having a lumen extending
from a proximal end to a distal end. It should be noted that any
particles which break free during therapy and aspiration procedures
will be kept at the site of the procedure within the working area
by the occlusive device occluding the distal portion of the vessel
in combination with the blood pressure coming from the proximal
portion of the vessel. The debris is prevented from migrating
elsewhere, and remains localized for removal by aspiration. Further
details regarding aspiration catheters are described in assignee's
pending application entitled ASPIRATION SYSTEM AND METHOD,
application Ser. No. ______, filed Feb. 19, 1998 (Attorney Docket
No. PERCUS.022CP1), the entirety of which is hereby incorporated by
reference. Once aspiration is completed, the balloon 20 may be
deflated to resume blood flow through the vessel.
[0106] Preferably, the procedure described above is perform twice
using a predilatation catheter and a dilatation catheter. The
predilatation catheter is a first therapy catheter which is
advanced over the proximal end of the guidewire 10 to the point of
the lesion 42. The balloon on the distal end of the predilatation
catheter has a first inflation diameter designed to perform a first
treatment to the lesion 42. The predilatation catheter is then
exchanged with an aspiration catheter to aspirate emboli formed by
the first treatment, while the occlusion balloon remains inflated.
After aspiration, the occlusion balloon 20 is deflated to allow
blood to flow to organs downstream, and then reinflated after
exchange of the aspiration catheter for the dilatation catheter.
This second therapy catheter has a dilatation balloon with a larger
inflation diameter than the first dilatation balloon so as to
further compress the plaque 42 against the vessel walls. Once this
treatment is completed, the second therapy catheter is exchanged
with the aspiration catheter for removing emboli from the blood
system.
[0107] Further exchanges of therapy catheters having successively
larger dilatation balloons with aspiration catheters are also
contemplated by the present invention, with each exchange occurring
while the distal occlusion balloon is inflated. Moreover, it is not
always necessary to follow treatment with a therapy catheter with
an exchange for an aspiration catheter. Therapy catheters can be
exchanged with other therapy catheters to perform further treatment
in the blood vessel before an exchange with an aspiration catheter
is made.
[0108] 3. Stent Catheter Exchange
[0109] In the preferred method of the present invention, following
treatment of the lesion and aspiration by one or more sequences as
described above, the occlusion balloon 20 is deflated to resume
blood flow to the vessel. Another catheter exchange is performed
whereby the aspiration catheter is removed from the guidewire 10
and exchanged with a deployment catheter carrying a stent. As shown
in FIG. 3D, the deployment device may be a catheter 70 carrying a
balloon 72 holding an angioplasty stent 74. Once the catheter 70
reaches the point of lesion, the occlusion balloon 20 is reinflated
to prevent any particles dislodged by the stenting process from
migrating downstream. The balloon 70 is then inflated to expand the
stent to its working diameter, and is sized to implant the stent
into the vascular wall. Plastic deformation of the stent prevents
it from collapsing once the balloon has been deflated and removed
from the patient. Further details regarding stents are contained in
assignee's pending application entitled STENT POSITIONING APPARATUS
AND METHOD, application Ser. No. 08/744,632, filed Nov. 6, 1996,
the entirety of which is hereby incorporated by reference. After
the stent is in place, an exchange may be performed between the
deployment catheter 70 and the aspiration catheter 60 to remove any
debris formed by the stenting process. After aspiration, the
occlusion balloon 20 is deflated and the aspiration catheter is
removed.
[0110] B. Alternative Exchange Methods
[0111] The method described above is merely exemplary, and it
should be recognized that the catheter exchange method may utilize
a variety of exchanges of different types of catheters while emboli
are being contained. 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. 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.
[0112] FIG. 4 shows an alternative embodiment employing a distal
occlusion catheter for use in directing shockwaves to disintegrate
the plaque 42. The catheter 10 comprises a radiopaque marker 44
located proximal to the distal balloon 20. The marker 44 is used to
locate the plaque 42 for targeting by external shock wave generator
46. After inflation of the balloon, the shock wave generator 46 is
focused onto the plaque 42 by use of the radiopaque marker to
disintegrate the plaque.
[0113] After treatment of the plaque by the shock wave generator,
an aspiration catheter 60 as described in FIG. 3C may be slid over
the guidewire 10 for aspirating the emboli created by the shock
wave treatment. Alternatively, the shock wave treatment may be
performed with the aspiration catheter 60 already advanced over the
guidewire 10. In such an embodiment, a radiopaque marker may either
be placed on the guidewire or aspiration catheter itself for
targeting the location of the plaque. Furthermore, the method
described above may be implemented using ultrasounds for focusing
of the shock wave generator to the plaque. For instance, a target
balloon on a catheter may be advanced over the guidewire to the
location of the lesion and inflated with air. Air provides a medium
with a significantly different acoustical impedance than body
tissue. This results in good ultrasound visualization for targeting
the lesion. This catheter is then exchanged with an aspiration
catheter for removing emboli from the vessel. Further exchanges
with a stent deployment catheter or other types of therapy
catheters may be performed as described above.
[0114] FIG. 5 shows another alternative therapy method for treating
the plaque 42. A vibration delivery catheter 80 is advanced over
the guidewire 10 to a position adjacent the lesion 42. The
vibration delivery catheter is preferably a monorail catheter
having two lumens 82 and 84, lumen 82 serving as a passageway
through which the guidewire 10 passes, and lumen 84 serving as a
passageway for a waveguide or coupling member in the form of a wire
86. The guidewire lumen 82 as shown in FIG. 5 is located only on
the distal end of the vibration delivery catheter. However, the
lumen 82 can be made to extend the entire length of the catheter 80
if desired. One end of wire 86 contacts the lesion 42, while the
other end extends out of the free end of catheter 80 outside the
body of the patient and is attached to a transducer 88. With the
occlusion balloon 20 inflated, by activating the transducer the
wave guide 86 is caused to act on the lesion 42 with transverse and
longitudinal motion of the end of the wave guide to machine away or
disintegrate the lesion 42. Exchanges may be performed following
this treatment with the aspiration, therapy or other catheters as
described above.
[0115] FIG. 6 shows an alternative therapy method wherein a drug
delivery catheter 90 is advanced over guidewire 10 to dissolve the
plaque 42. The catheter 90 is preferably a monorail catheter having
two lumens 92 and 94, the lumen 92 riding over the guidewire 10.
The drug delivery lumen 94 extends from a proximal end 96a to a
distal end 96b, with the distal end 96b positioned adjacent the
lesion to be treated. At the proximal end, an infusion port 97 is
provided for delivering drugs 99 to the location of the lesion.
Preferable materials for use in dissolving the lesion 42 are TPA
(tissue plasminogen activator) available from Genentech, Inc., or
pro-urokinase, available from Abbott Laboratories. Also at the
proximal end, an aspiration port 98 is provided for removing emboli
created by the procedure. Alternatively, the drug delivery catheter
may be exchanged with a separate aspiration catheter for performing
emboli containment. After dissolution of the lesion 42, exchanges
may be made with stent carrying catheters or other catheters as
described above.
[0116] The exchange method as described in a preferred aspect of
the present invention is not applicable solely to procedures
dislodging emboli. Rather, the present exchange method also applies
to any situation wherein a distally occluding device prevents the
migration of undesired particles downstream. For instance, as shown
in FIG. 7, an aneurysm of an artery is shown, wherein a bulge 162
is found in artery 160. Guidewire 10 carrying distal occlusion
balloon 20 is advanced through the vessel such that the balloon 20
is located distal to the bulge 162. The balloon 20 is inflated so
that various treatment and/or aspiration catheters may be exchanged
to perform treatment on the aneurysm. In treating aneurysms, one
preferred method is to fill the bulge 162 with embolization
elements 164. The distal occlusion balloon 20 is necessary because
some of these particles may break free and migrate downstream. An
exchange is also desired for treating aneurysms because deployment
of particles 164 must be done sequentially, with subsequent
catheters delivering more and more embolization elements to fill
162. Thus, a catheter exchange over the guidewire 10 is desirable
for rapidly filling the bulge 162 while the distal occlusion
balloon 20 is inflated. An exchange is further desired to advance
an aspiration catheter into the vessel to remove any particles that
may have come loose while treating the aneurysm.
[0117] C. Exchange Methods Over Alternative Occlusive Devices
[0118] Although the embodiments described above refer to a distally
occluding balloon to prevent emboli from migrating downstream,
other methods for occluding the blood vessel may be used while
performing the exchange method described in a preferred aspect of
the present invention. With respect to all of these methods, the,
proximal ends of the expansion members are sized to allow an
exchange of catheters over the catheter or guidewire bearing the
expansion member. These methods as briefly discussed herein are
described in further detail below in the section entitled
"Expansion Members."
[0119] In FIGS. 35-36, a catheter apparatus is shown having a
self-expanding sealing mechanism. As shown in FIG. 35, the catheter
apparatus 1781 comprises a guiding catheter 1782 with a
self-expanding sealing mechanism 1791 mounted on distal end 1784.
The sealing mechanism 1791 is enclosed by an elongate sleeve 1796
having a collar 1801 mounted on the proximal extremity 1797 of
sleeve 1796. The collar 1801 serves as a mechanism for retracting
the sleeve to uncover self-expanding sealing mechanism 1791 after
the catheter has been deployed to permit the self-expanding sealing
mechanism 1791 to expand and form a seal with the vessel adjacent
the stenosis to be treated. Sleeve 1796 may be completely removed,
as shown in FIG. 36, to permit catheters with inner lumen diameters
substantially the same as the outer diameter of the guiding
catheter to be exchanged over the catheter. The various types of
occlusive devices provided at the distal end of these catheter
apparatuses and their manner of operation are more particularly
described below with respect to FIGS. 31-46.
[0120] The preferred exchange method of the present invention may
also be performed over catheters or guidewires employing
non-self-expanding or mechanically deployed sealing mechanisms. As
shown in FIGS. 47-51B, described in further detail below, a pull
wire device may be utilized for deploying an occlusive mechanism to
a blood vessel while still maintaining a low profile at the
proximal end of the device to allow for an exchange. As shown in
FIG. 49, one pull wire device comprises an elongate member 1166
over which therapy, aspiration and other catheters may be advanced
and removed. At the proximal end of the device, a rotatable handle
1180 is attached to a locking member 1184. The wire 1140 is pulled
by handle 1180 from its configuration shown in FIG. 50A until the
locking member 1184 clears the proximal end of elongate member
1166, at which point member 1184 is rotated to the configuration
shown in FIG. 50B to hold the wire 1140 taut. The handle 1180 and
locking member 1184 are dimensioned to be substantially the same
size as the elongate member 1166, which preferably has an outer
diameter of 0.014 inches, such that other catheters may be advanced
and removed over the elongate body 166 without interference from
the handle 1180 or locking member 1166.
[0121] FIG. 51A shows an alternative pull wire mechanism wherein a
spacer 1194 is placed between a handle 1190 and elongate body 1166
to pull wire 1140 and deploy the sealing mechanism. Because the
handle 1190 and the spacer 1194 have the same diameter as the
elongate body 1166, the exchange method as described above may be
performed over the elongate body 1166 with catheters having
relatively small inner diameters.
[0122] D. Speed of Exchange
[0123] The method described by a preferred aspect of the present
invention is particularly advantageous in that it allows for a
rapid exchange of catheters to reduce the time that a blood vessel
is occluded by a balloon or other occlusive device. FIG. 8 shows
experimental results for 24 patients undergoing percutaneous
transluminal coronary angioplasty (PTCA) and subsequent stenting
treatments in saphenous vein grafts. More particularly, FIG. 8
shows the inflation durations of occlusion balloon 20 during the
treatment procedure, i.e., the time that the balloon 20 is inflated
to occlude the vessel. The preferred method minimizes the times
that the occlusion balloon is inflated by conducting the treatment
in stages. For instance, a first stage, corresponding to a first
inflation time, may comprise a sequence of therapy and aspiration
treatments. After occlusion balloon inflation, a therapy catheter
carrying a dilatation balloon may be used to compress the lesion.
Exchanges with subsequent therapy catheters may then be performed,
as long as end organs positioned downstream can tolerate the loss
of blood due to blockage by the occlusion balloon. At the end of
this first stage of treatment, the therapy catheter positioned on
the guidewire is exchanged for an aspiration catheter. After
aspiration is completed, the balloon is deflated.
[0124] Second and third inflation durations as indicated in FIG. 8
may similarly correspond to subsequent sequences of therapy and
aspiration treatments. After the occlusion balloon is deflated and
the first sequence ends, the aspiration catheter is exchanged for
another therapy catheter. Once the second therapy catheter is in
place, the occlusion balloon is reinflated and the lesion is
treated in the same manner as described above. Alternatively, the
second and third inflation durations may refer to a therapy
catheter which deploys a stent. In this embodiment as well, the
occlusion balloon is not inflated until the aspiration catheter has
been exchanged with the stent deploying catheter. By performing the
treatment in such a manner, the amount of time that blood flow is
blocked in the treated vessel is minimized.
[0125] Thus, the inflation durations as shown in FIG. 8 generally
represent the amount of time it takes to perform a therapy
treatment using one or more therapy catheters exchanged over the
guidewire, exchange the therapy catheter for an aspiration
catheter, and aspirate emboli. As shown in FIG. 8, the mean time to
accomplish this procedure was about 150 seconds. FIG. 8 also shows
a general reduction in inflation durations from patient 1 to
patient 24 as the clinician improved in performing the exchange
over time. Accordingly, in a preferred aspect of the present
invention, providing a rapid exchange method for use during emboli
containment allows the clinician to quickly perform a treatment
procedure while minimizing the risk to the patient due to blockage
of blood flow.
[0126] The preferred method also reduces the treatment time by
providing the catheter 10 with a side-access inflation port 22, as
shown in FIG. 9. To inflate the occlusion balloon 20, the guidewire
10 is preferably inserted into an inflation adaptor, as described
below with respect to FIGS. 16-19, 24-28C. By providing the
inflation port 22 on the side of the guidewire 10, the adaptor can
easily be attached to the guidewire and quickly inflate or deflate
the balloon 20 by a simple movement such as moving actuator 220, as
shown in FIG. 16. This in turn reduces the amount of time that the
balloon 20 occludes a treated blood vessel.
[0127] Furthermore, use of an adaptor makes the catheter much
easier to handle. Because the guidewire 10 is so small, it may
difficult to handle by clinicians. By using an adaptor, however,
the clinician need only insert the wire into the adaptor, close the
adaptor, and actuate the adaptor, as described in further detail
below.
[0128] Additionally, as shown in FIG. 17C, an adaptor 200,
described in further detail below, is preferably attached to a low
volume syringe 294 and a high volume syringe 295. An extension line
293 is attached to fitting 210 to allow fluid flow to and from
adaptor 200. Low volume syringe 294 is provided for accurate
inflation of balloon 20. More particularly, low volume syringe is
provided so that inflation can be performed safely and quickly.
High volume syringe 295 is provided for rapid deflation of balloon
20. By using this syringe system, inflation and deflation of
balloon 20 through an adaptor can be performed quickly and
efficiently. Further details regarding a syringe system are
described in assignee's pending application entitled SYRINGE AND
METHOD FOR INFLATING LOW VOLUME CATHETER BALLOONS, application Ser.
No. ______, filed Feb. 19, 1998 (Attorney Docket No.
PERCUS.023CP1), the entirety of which is hereby incorporated by
reference.
[0129] Moreover, by providing an access port on the side of the
tubular body 18, the port 22 can be made with a large cross-section
to increase the amount of fluid passing through the port. This in
turn decreases the time necessary for inflating or deflating
balloon 20. In addition, as described in more detail below, the use
of a side-access port allows for more efficient opening and closing
of the port 22. Preferably, a sealing member 30 moves slidably
within tubular body 18 to plug and unplug port 22. Because member
30 remains attached to the catheter 10 even when the port 22 is
open, the operator never has to remove the sealing member.
Accordingly, the sealing member is always in place, thereby
reducing the time that it takes to open or close inflation port
22.
[0130] The speed of exchange is also increased by using an
aspiration catheter with a high volume syringe. As shown in FIG.
17D, aspiration catheter 60 is attached to an aspiration line 296,
connecting the aspiration catheter 60 with a high volume syringe
297. The high volume syringe allows rapid aspiration of emboli from
the treated vessel, thereby reducing the time that the occlusion
balloon 20 must be inflated. Further details regarding aspiration
are disclosed in the above-referenced application entitled
ASPIRATION SYSTEM AND METHOD.
[0131] E. Diagnostic Methods
[0132] The preferred exchange method of the present invention is
also applicable to diagnostic methods. In one preferred aspect of
the present invention, a method is provided wherein emboli found or
created in the body are removed from the body for diagnostic
testing. A guidewire with a distal occlusive device is inserted
into the body to a point distal of plaque. A therapy catheter is
advanced over the guidewire to the location of the plaque. After
the distal occlusion device is deployed, a therapy treatment, such
as inflation of a dilatation balloon or any other means as
described above, is performed to break up the plaque and produce
emboli. The therapy catheter is then exchanged with an aspiration
catheter while the occlusion device remains deployed, and the
aspiration catheter removes the particulate matter for
analysis.
[0133] In the procedures conducted on the 24 patients described
above in FIG. 8, particulate matter was retrieved in all but 1 of
23 procedures and 45 of 48 aspirations. Mean particle size was 168
.mu.m (range 8 to 3,427 .mu.m) in the major axis, 80 .mu.m (range 6
to 815 .mu.m) in the minor axis, with an area of 32,117 .mu.m.sup.2
(range 42 to 4,140,000 .mu.m.sup.2). Particulate material consisted
predominantly of cholesterol clefts, lipid-rich macrophages,
fibrous caps, necrotic core and fibrin material. Atherosclerotic
material in the precipitate sections was quantified as maximal in 5
aspirates, moderate in 9, minimal in 26, and none in 3.
[0134] Vein graft aspirate was collected in tubes containing
EDTA-citrate buffer and treated with 1% saporin to lyse interfering
red blood cells. The remaining material was fixed in 10% neutral
buffered formalin or glutaraldehyde and processed for light
microscopy and scanning electron microscopy, respectively.
Immunohistochemical staining was performed in some cases to confirm
the presence of foam cells, smooth muscle cells and endothelial
cells. A semiquantitative analysis of particulate bulk was
performed. Particulate matter examined by scanning electron
microscopy was measured in its major and minor access and the
resultant two dimensional area, calculated. This suspended
particulate matter may play a role in the pathogenesis of distal
emoblization, no-reflow, infarction, and morbidity and mortality
following vein graft intervention.
[0135] Tables 1 and 2 below show the results of quantitative
analyses performed on vein graft aspirates. Table 1 shows the
frequency of acellular plaque material in vein graft aspirates.
Table 2 shows the frequency of cellular plaque material in vein
graft aspirates. Values are expressed as the frequency of positive
samples per case. Numbers in parentheses represent the percentage
of positive samples.
1TABLE 1 Frequency of Acellular Plaque Material in Vein Graft
Aspirates. Necrotic Cholesterol Plaque Samples Debris Clefts
Collagen Hemorrhage PTCA 15/15 (100) 8/15 (23) 4/15 (27) 3/15 (20)
Stent 1 15/18 (83) 6/18 (33) 6/18 (33) 4/18 (22) Stent 2 7/7 (100)
4/7 (57) 1/7 (14) 1/7 (14)
[0136]
2TABLE 2 Frequency of Cellular Plaque Material in Vein Graft
Aspirates. Samples Foam Cells Smooth Muscle Cells Platelet
Aggregates PTCA 14/15 (93) 0/15 (0) 2/15 (13) Stent 1 17/18 (94)
0/18 (0) 4/18 (22) Stent 2 6/7 (86) 0/7 (57) 2/7 (29)
[0137] II. Inflatable Guidewire Apparatus
[0138] One preferred embodiment for a catheter for use in the
preferred method is shown in FIG. 9. In FIG. 9, there is depicted a
catheter 10 incorporating the low profile valve in a preferred
aspect of the present invention. Although illustrated in the
context of a simple occlusion balloon catheter, having a single
inflation lumen and a single inflatable balloon, it is to be
understood that the low profile valve can be readily adapted to a
wide variety of balloon catheters, including those having
additional functionalities, structures, or intended uses. For
example, the low profile valve could be easily adapted to catheters
having expandable members other than occlusion balloons, such as
therapeutic dilatation balloons. Furthermore, the low profile valve
may also be incorporated into catheters having two or more lumens.
The manner of adapting the low profile valve to catheters having
these various functionalities, structures, or intended uses will
become readily apparent to those of skill in the art in view of the
description which follows.
[0139] Catheter 10 generally comprises an elongate flexible tubular
body 18 extending between a proximal control end 12 and a distal
functional end 14. Tubular body 18 has a central lumen 40 which
extends between ends 12 and 14. Lumen 40 has an opening 23 at
proximal end 12, and is sealed fluid tight at distal end 14. The
length of tubular body 18 may be varied considerably depending upon
the desired application. For example, where catheter 10 is to be
used as a guidewire for other catheters in a conventional
percutaneous transluminal coronary angioplasty procedure involving
femoral artery access, lengths of tubular body 18 in the range of
from about 120 to about 300 centimeters are preferred, with a
length of about 180 centimeters often being used. Alternately, for
a different treatment procedure, not requiring as long a length of
tubular body 18, shorter lengths of tubular body 18 may be
provided.
[0140] Typically, tubular body 18 will have a generally circular
cross-sectional configuration with an outer diameter within the
range of from about 0.010 inches to 0.044 inches. Optimally, in
most applications where catheter 10 is to be used as a guidewire
for other catheters, the outer diameter of tubular body 18 ranges
from 0.010 inches to 0.038 inches, and preferably is 0.020 inches
in diameter or smaller, more preferably 0.014 inches in outer
diameter or smaller. The diameter of lumen 40 will be dictated, in
part, by the outside diameter of tubular body 18. For example,
where tubular body 18 has an outer diameter of 0.014 inches,
central lumen 40 may have an inner diameter of from about 0.008
inches to about 0.010 inches. The diameter of lumen 40 should be
large enough to incorporate the low profile valve described below,
and large enough to permit sufficient fluid passage for balloon
inflation.
[0141] Noncircular cross-sectional configurations of lumen 40 can
also be adapted for use with the low profile valve described in a
preferred embodiment of the present invention. For example,
triangular rectangular, oval, and other noncircular cross-sectional
configurations are also easily incorporated for use with present
invention, as will be appreciated by those of skill in the art. The
manner of adapting the valve of the present invention will become
readily apparent in view of the description which follows.
[0142] In the preferred embodiment, the tubular body 18 functions
as a guidewire, and thus, tubular body 18 must have sufficient
structural integrity, or "pushability," to permit catheter 10 to be
advanced through vasculature to distal arterial locations without
buckling or undesirable bending of tubular body 18. It is also
desirable for tubular body 18 to have the ability to transmit
torque, such as in those embodiments where it may be desirable to
rotate tubular body 18 after insertion into a patient. A variety of
biocompatible materials, known by those of skill in the art to
possess these properties and to be suitable for catheter
manufacture, may be used to fashion tubular body 18. For example,
tubular body 18 may be made of stainless steel, or may be made of
polymeric materials such as nylon, polyamide, polyimide,
polyethylenes, or combinations thereof. In one preferred
embodiment, the desired properties of structural integrity and
torque transmission are achieved by forming tubular body 18 out of
an alloy of titanium and nickel, commonly referred to as nitinol.
In a more preferred embodiment, the nitinol alloy used to form
tubular body 18 is comprised of about 50.8% nickel and the balance
titanium, which is sold under the trade name Tinel (TM) by Memry
Corp. It has been found that a catheter tubular body having this
composition of nickel and titanium exhibits great flexibility and
improved kink resistance in comparison to other materials. One
preferred embodiment of tubular body 18 is disclosed in our
copending application entitled HOLLOW MEDICAL WIRES AND METHODS OF
CONSTRUCTING SAME, application Ser. No. 08/812,876, filed on Mar.
6, 1997, the entirety of which is incorporated herein by
reference.
[0143] The distal end 14 of catheter 10 is provided with an
atraumatic distal tip 16, and an inflatable balloon 20, as
illustrated in FIG. 9. Inflatable balloon 20 may be made from any
of a variety of materials known by those of skill in the art to be
suitable for balloon manufacture. For example, inflatable balloon
20 may be formed of materials having a compliant expansion profile,
such as polyethylene or latex. In one preferred embodiment, where
inflatable balloon 20 is to be used as an occlusion balloon, it is
preferably formed of a block copolymer of
styrene-ethylene-butylene-styrene (SEBS), sold under the trade name
C-Flex.TM.. One preferred embodiment of a C-Flex occlusion balloon
is disclosed in our copending application entitled BALLOON CATHETER
AND METHOD OF MANUFACTURE, application Ser. No. ______, filed on
Feb. 19, 1998 (Attorney Docket No. PERCUS.010CP1), the entirety of
which is incorporated herein by reference. Alternately, in those
embodiments where inflatable balloon 20 is to serve as a dilatation
balloon, it may be formed of materials having a noncompliant
expansion profile, such as polyethylene terephthalate. Inflatable
balloon 20 may be attached to tubular body 18 in any manner known
to those of skill in the art, such as heat bonding or through use
of adhesives.
[0144] As shown in FIG. 9, catheter 10 is provided with a
side-access inflation port or opening 22 formed in tubular body 18
at a point several centimeters distal from opening 23. Inflation
port 22 is in fluid communication with central lumen 40 extending
through tubular body 18. A fill hole (not shown) is formed in
tubular body 18 within the region enclosed by inflatable balloon
20, such that fluid passing through inflation port 22 and into
lumen 40 may inflate balloon 20. Conversely, an inflated balloon 20
can be deflated by withdrawal of fluid from balloon 20, through
lumen 40, and out of side-access inflation port 22.
[0145] The low profile valve may be used with catheters such as
that described above, all well as with different catheters having
different structures. In one preferred embodiment, the low profile
valve comprises a sealing member which is movably positioned within
the inner lumen of a catheter. The catheter has an inflation port,
which, in some embodiments, is also an opening to the inner lumen
at the proximal end of the catheter. An inflatable balloon is
positioned on the distal end of the catheter, which is in fluid
communication with the lumen and inflation port. The sealing member
is inserted through the proximal opening into the lumen, with a
portion of the sealing member extending outwardly from the proximal
end of the catheter. The portion of the sealing member inserted
into the lumen has a sealer portion which forms a fluid tight seal
with the inner lumen to prevent fluid from passing past the sealer
portion.
[0146] By application of a pushing or pulling force on the
extending sealing member portion, the sealing member may be
partially advanced within or withdrawn from the lumen, thereby
moving the sealer portion within the lumen. In this manner, the
sealer portion may be positioned within the lumen either proximally
or distally of the inflation port. When the sealer portion is
positioned proximally of the port, the valve is in the "open"
position. When the valve is open, an unrestricted fluid pathway is
established between the inflation port and the balloon, such that
an external pressurized fluid source may be connected to the
inflation port to inflate the balloon, or if the balloon is already
inflated, the balloon may be deflated by application of a vacuum to
the inflation port to withdraw fluid from the balloon. When the
sealer portion is positioned distally of the inflation port, the
valve is in the closed position, as the fluid tight seal between
the lumen and the sealer portion prevents fluid from passing either
to or from the balloon through the inflation port. Furthermore,
when the valve is closed after balloon inflation, the fluid tight
seal created by the sealer portion maintains the balloon in the
inflated state in the absence of an external fluid source, by
preventing the pressurized fluid within the balloon from
escaping.
[0147] Referring to FIGS. 10, 11A and 11B, there is depicted one
embodiment of the low profile valve of the present invention, as
used with the catheter of FIG. 9. Catheter 10, as described above,
has a side-access inflation port 22 which is in fluid communication
with central lumen 40, and through which fluid may be introduced to
inflate balloon 20. Central lumen 40 has an opening 23 at proximal
end 12. A sealing member 30 is inserted into lumen 40 through
opening 23. Sealing member 30 may be partially advanced within or
withdrawn from lumen 40 by the application of a longitudinal force
on sealing member 30 directed toward or away from proximal end 12,
respectively.
[0148] Sealing member 30 comprises a main shaft 33, a tapering
region 31, and a wire 32. Sealing member 30 may be formed as solid
piece out of suitable metals, such as stainless steel, nitinol and
the like. For example, sealing member 30 may be formed as a solid
cylindrical piece, and then be coined down at points along its
length to form tapering region 31 and wire 32. Alternately, one or
more of the main shaft 33, tapering region 31, or wire 32 may be
formed separately, and then attached to the other piece(s) by
conventional means, such as soldering, to form sealing member 30.
Polymeric materials, such as Delron.TM., nylon, and the like, may
also be used to form sealing member 30, either as a solid piece, or
as separate pieces which are later joined to form the sealing
member.
[0149] Although not required, in one preferred embodiment, main
shaft 33 has an outer diameter no larger than the outer diameter of
the catheter tubular body 18. Thus, if the outer diameter of
tubular body 18 is 0.014 inches, the diameter of main shaft 33, and
thus the largest diameter of sealing member 30, is no larger than
0.014 inches. Furthermore, it is also preferred that main shaft 33
extend proximally from opening 23 by a distance of at least several
centimeters to facilitate the application of longitudinal forces on
main shaft 33 to manipulate the position of wire 32 in lumen 40.
Moreover, after catheter 10 has been fully inserted into a patient,
an extending main shaft 33 advantageously functions much like a
conventional guidewire extension, providing a starting point for
the clinician to insert other catheters over main shaft 33 and
catheter 10.
[0150] The combined length of catheter 10 and extending main shaft
33 may be varied considerably at the point of manufacture, and may
be adapted to the requirements of the other catheters which are to
be used with catheter 10 and main shaft 33. For example, where
catheter 10 is to be used as a guidewire for other catheters in an
"over-the-wire" embodiment, it is preferred that the total length
of catheter 10 with extending main shaft 33 be about 300
centimeters. Alternately, when catheter 10 is to be used as a
guidewire for other catheters in a single operator embodiment, or
"RAPID-EXCHANGE" embodiment, it is preferred that the total length
of catheter 10 with extending main shaft 33 be about 180
centimeters. As can be readily appreciated, the individual lengths
of catheter 10 and extending main shaft 33 can be varied
considerably and yet still achieve the overall desired combined
length. For example, a catheter 10 having a length of 180
centimeters can be provided with an extending main shaft 33 having
a length of 120 centimeters, to achieve the 300 centimeter total
desired length for over-the-wire embodiments.
[0151] In another embodiment, where it is undesirable to have a
long main shaft extending proximally from catheter 10, a main shaft
extending proximally only several centimeters may be provided. The
shorter main shaft may be provided with an attachment (not shown),
which is adapted to releasably secure longer extensions to the main
shaft, such that it can also be used to facilitate the use of
catheter 10 as a guidewire for other catheters.
[0152] It is preferred that main shaft 33 have a larger diameter
than the other portions of sealing member 30, to make it easier to
apply moving forces to sealing member 30. Thus, a tapering region
31 may be disposed between main shaft 33 and wire 32, to transition
the outer diameter of sealing member 30 from the larger diameter of
main shaft 33 to the smaller diameter of wire 32. For the
embodiment illustrated in FIGS. 9-11B, it is wire 32 which is
slidably inserted through opening 23 and into lumen 40.
Accordingly, the outer diameter of wire 32 must be less than the
inner diameter of lumen 40, so that wire 32 may be slidably
accommodated therein. Moreover, in those embodiments where the end
of wire 32 extends distally past inflation port 22 when the valve
is in the open position, the gap between the outer diameter of wire
32 and the inner diameter of lumen 40 must be sufficiently large so
as not to significantly restrict the flow of fluid passing through
lumen 40 to or from inflation port 22. Optimally, to facilitate the
sliding of wire 32 within lumen 40 and to permit inflation fluid
flow, wire 32 is from about 0.001 inches to about 0.004 inches
smaller in outer diameter than the inner diameter of lumen 40.
[0153] In a preferred embodiment, wire 32 and catheter 10 are
provided with positive stops to prevent the withdrawal of wire 32
from the proximal end of catheter 10. For the embodiment depicted
in FIGS. 11A and 11B, this consists of a pair of cooperating
annular rings mounted on wire 32 and lumen 40, respectively. A
first annular ring 34 is coaxially and fixedly mounted on wire 32
at a point on wire 32 contained within lumen 40. A second
corresponding fixed annular ring 35 projects inwardly from the
interior surface of lumen 40 near proximal end 12. The inner
diameter of the opening of annular lumen ring 35 is slightly larger
than the outer diameter of wire 32, so as not to restrict the
movement of wire 32 within lumen 40. However, the outer diameter of
annular wire ring 34 is greater than the inner diameter of the
opening of ring 35, such that rings 34 and 35 cooperate to prevent
wire 32 from being withdrawn from the proximal end of catheter
10.
[0154] Rings 34 and 35 may be formed of any material which may be
attached to wire 32 and lumen 40, respectively, and which possesses
sufficient structural rigidity to act as a stop. Examples of
suitable materials are metals and various hard polymers, such as
stainless steel and Teflon.TM.. In one preferred embodiment, where
wire 32 and tubular body 18 are both formed of nitinol, rings 34
and 35 are also formed of nitinol and are soldered to wire 32 and
the inner surface of lumen 40, respectively.
[0155] As will be appreciated by those of skill in the art,
cooperating stopping structures other than those described herein
may also be used to prevent full withdrawal of wire 32 from
catheter 10. For example, annular ring 34 may be replaced by one or
more protrusions extending radially outwardly from wire 32, which
are also adapted to cooperate with ring 35 to prevent withdrawal of
wire 32. Alternately, annular ring 35 might be replaced by crimping
tubular body 18 slightly to restrict movement of ring 34 to points
proximal of the crimp.
[0156] A lumen sealer portion 36 is coaxially and fixedly mounted
on wire 32. Sealer portion 36 is positioned on wire 32 at a point
distal to ring 34, such that by partial withdrawal of wire 32 from
catheter 10, as depicted in FIG. 11A, sealer portion 36 is capable
of being positioned within lumen 40 at a point proximal to
inflation port 22. Sealer portion 36 is also located on wire 32 at
a point such that when wire 32 is fully inserted into lumen 40, as
depicted in FIG. 11B, sealer portion 36 either fully covers
inflation port 22, or is located within lumen 40 at a point distal
to inflation port 22. The leading edge 36a and trailing edge 36b of
sealer portion 36 are preferably tapered, so that the edges of
sealer portion 36 do not catch upon inflation port 22 when sealer
portion 36 passes by port 22.
[0157] It is preferred that sealer portion 36 form a fluid tight
seal with the outer diameter of wire 32 and the inner diameter of
lumen 40, such that fluid in lumen 40 is prevented from flowing
past sealer portion 36. In the embodiment illustrated in FIGS. 11A
and 11B, this is achieved by providing wire 32 with a sealer
portion 36 that firmly contacts the entire inner circumference of a
section of lumen 40 along a substantial portion of the length of
sealer portion 36. The fit between the outer surface of sealer
portion 36 and the inner surface of lumen 40 is tight, such that a
fluid tight seal is created which prevents fluid from passing past
sealer portion 36. However, sealer portion 36 must be capable of
being moved within lumen 40 upon movement of main shaft 33,
tapering region 31, and wire 32. Thus, the fit between sealer
portion 36 and lumen 40 must not be so tight as to prevent movement
of sealer portion 36 in lumen 40 upon application of sufficient
longitudinal force on main shaft 33. Moreover, the fluid tight seal
created by the fit between lumen 40 and sealer portion 36 must be
maintained as sealer portion 36 is moved back and forth within
lumen 40.
[0158] Sealer portion 36 must also be capable of maintaining a seal
at fluid pressures conventionally used to inflate catheter
balloons, and should be capable of maintaining a seal at pressures
which exceed conventional inflation pressures. Preferably, sealer
portion 36 is capable of maintaining a seal at pressures up to
about 10 atmospheres, more preferably pressures up to about 30
atmospheres, and most preferably at pressures up to about 60
atmospheres. Sealer portion 36 is also preferably capable of
undergoing multiple valve-opening and valve-closing cycles without
losing the structural integrity required to form seals capable of
withstanding pressures of from about 10 atmospheres to about 60
atmospheres. Optimally, sealer portion 36 is capable of undergoing
at least 10, and preferably at least 20, valve-opening and closing
events and still be capable of maintaining a fluid tight seal at a
pressure of 10 atmospheres.
[0159] In one embodiment, the desired properties of sealer portion
36 are attained by forming sealer portion 36 out of an extruded
polymeric tubing. Pebax.TM. tubing having an inner diameter of
0.008 inches and an outer diameter of 0.017 inches, and a hardness
of 40 durometers, is first necked by heating the extruded tubing to
a temperature of between 210 and 250 degrees Fahrenheit. Tube
pieces of about 0.5 mm in length are then cut from the larger
tubing. The cut Pebax.TM. tubes are then placed on a nitinol wire
having an outer diameter of about 0.006 inches, and are heated and
shaped to recover a tube that has an outer diameter of between
0.010-0.011 inches. The adhesive Loctite 4014.TM. may then be used
to bond the heat-shaped Pebax.TM. tubing to the nitinol wire. When
the adhesive dries, the leading and trailing edges of the bound
Pebax.TM. seal may be trimmed, leaving an annular lumen contact
length of about 0.010 inches (0.25 mm). The wire bearing the
Pebax.TM. sealer portion may then be inserted into the opening of a
nitinol catheter having a lumen with an inner diameter of about
0.0096 inches. Sealer portions of this type have been observed to
hold pressures of up to 30 atmospheres, and are capable of
undergoing multiple valve-opening and closing events without
significantly diminishing the seal strength.
[0160] As will be appreciated by those of skill in the art,
different forms of Pebax.TM. starting materials may be used to form
sealer portion 36. For example, in another preferred embodiment,
similar steps were used with a Pebax.TM. tube having similar
dimensions but a hardness of 70 durometers, to create a sealer
portion.
[0161] It is contemplated by the present inventors that methods and
materials other than those described above may be used to make a
lumen sealer portion having the desired properties. For example,
materials other than Pebax.TM., silicone, latex rubber, C-Flex.TM.,
Nusil.TM. and gels, which are known to possess adequate surface
properties to function as a sealer portion, and also be lubricous
enough to be moved within lumen 40, may also be used to form sealer
portion 36. In addition, sealer portion 36 may be attached to wire
32 by alternate means, such as by integrally molding sealer portion
36 to wire 32, dip forming sealer portion 36 to wire 32, as well as
other means of attaching a polymeric material to a wire known to
those of skill in the art.
[0162] Other embodiments of sealer portion may not create a
completely fluid tight seal between the sealer portion and the
inner lumen at balloon inflation pressures. In these embodiments,
however, the sealer portion creates a seal which prevents
substantially all inflation fluid flow past the sealer portion,
such that the inflatable occlusive device is maintained in an
almost fully expanded state for extended periods of at least one
minute, preferably 2 or more minutes, more preferably at least 10
minutes, and optimally at least 20 minutes or longer, and still be
capable of providing clinically effective occlusion of any emboli
particles in the blood vessel during this time period.
[0163] In a preferred embodiment, there is provided movement-force
increasing structure, to increase the force required to move sealer
portion 36 from the valve-closed to the valve-open position.
Structure of this type advantageously minimizes the risk of an
accidental opening of the valve, and subsequent balloon deflation,
during a medical procedure. In the embodiment illustrated in FIGS.
11A and 11B, this is achieved by providing a biasing spring 37,
which surrounds wire 32 between stops 34 and 35. Spring 37 exerts a
force on stop 34, pushing it, and thus wire 32 and sealer portion
36, in the distal direction, so that sealer portion 36 forms a
fluid tight seal by either covering port 22 or by being positioned
within the lumen at a point distal to port 22. Consequently, in the
absence of a competing force, spring 37 maintains sealer portion 36
in the valve-closed position. Sealer portion 36 may be moved
proximally to the valve-open position by application of a
longitudinal force on main shaft 33 directed proximally from end 12
of sufficient magnitude to overcome the force of spring 37.
Optimally, spring 37 is selected so that the force that must be
applied to main shaft 33 to overcome the force of spring 37 is from
about 0.3 to about 1.0 pound-foot. In alternative embodiments, the
movement force increasing structure may comprise waves introduced
into the wire just proximal of the sealer portion, as described
below, which also may require 0.3 to 1.0 pound-foot of force to
overcome.
[0164] Referring to FIGS. 12 and 13, there is illustrated in
alternative embodiment of the valve of the present invention. The
alternative embodiment comprises a catheter 110 which may have
features which are substantially identical, in materials,
structure, and function, as the catheter described in connection
with FIGS. 9-11B. Catheter 110 has a proximal end 112, and a distal
end (not shown) to which is mounted an expandable member, such as
an inflatable balloon. A central lumen 140 extends within tubular
body 118 between the proximal and distal ends. An opening 123 to
lumen 140 is present at the proximal end 112 of catheter 110.
[0165] A sealing member 130 is inserted into lumen 140 through
opening 123, as described previously. Sealing member 130 comprises
a sealer portion 136, a wire 132, annular rings 134 and 135, and
support member 150. Sealing member 130 may be formed out of
materials and by methods as described previously.
[0166] As illustrated in FIGS. 12 and 13, the outer diameter of
wire 132 is less than the inner diameter of lumen 140, such that
sealing member 130 is slidably insertable into lumen 140.
Furthermore, a lumen sealer portion 136 is coaxially and fixedly
mounted to wire 132 near the distal end of wire 132. Sealer portion
136 forms a fluid tight seal with the outer diameter of wire 132
and the inner diameter of lumen 140, such that fluid introduced
into lumen 140 through opening 122 is prevented from flowing past
sealer portion 136 at normal balloon inflation pressures of 1 to 3
atmospheres for occlusive devices, and as much at 10 atmospheres or
more for other types of balloons. Sealer portion 136 may be
provided with leading edge 136a and trailing edge 136b, both
tapered, to facilitate movement of sealing portion 136 proximally
and distally of inflation port 122. Sealer portion 136 forms a
fluid tight seal by firming contacting the entire inner
circumference of a section of lumen 140 along a substantial portion
of the length of sealer portion 136. As described previously,
sealer portion 136 prevents substantially all fluid flow past the
seal created by sealer portion 136, and the movement of sealer
portion 136 proximally and distally of port 122 may be used to
effect the valve-open and valve-closed positions.
[0167] Cooperating positive stops, consisting of hollow cylinders
134 and 135 are provided to prevent withdrawal of sealing member
130 from lumen 140. Hollow cylinder 135 is attached to the inner
surface of lumen 140 by adhesives, soldering, crimping, or by other
means known to those of skill in the art, such that the proximal
portion of hollow cylinder 135 extends within lumen 140, and is
secured therein, and the distal portion of cylinder 135 extends
from proximal end 112. Cylinder 135 has a lumen (not shown)
extending therethrough. The diameter of the cylinder lumen is
larger than the outer diameter of wire 132, so that movement of
wire 132 is not restricted. A second hollow cylinder 134,
preferably of shorter length, is placed over wire 132 and is
fixedly mounted to wire 132, by soldering, or other means, at a
point distal to cylinder 135. The outer diameter of cylinder 134 is
less than the inner diameter of lumen 140, so as not to restrict
the movement of wire 132 within lumen 140. However, the outer
diameter of cylinder 134 is greater than the inner lumen diameter
of cylinder 135, so that cylinders 134 and 135 act as cooperating
stops, to prevent wire 132 from being withdrawn from lumen 140.
Cylinders 134 and 135 may be formed of any material which may be
attached to wire 132 and lumen 140, respectively, and which
possesses sufficient structural rigidity to act as a stop. Examples
of suitable materials are metals and various hard polymers, such as
stainless steel, Teflon.TM., and the like. In one preferred
embodiment, where wire 132 and tubular body 118 are both formed of
nitinol, cylinders 134 and 135 are also formed of nitinol, and are
soldered to wire 132 and the inner surface of lumen 140,
respectively.
[0168] The distal portion of cylinder 135 extending from proximal
end 112 is inserted into support member 150. Support member 150
comprises a tubular body 158 having an outer diameter and inner
lumen diameter which are approximately the same as tubular body
118. Consequently, because the outer diameter of cylinder 135 is
less than the inner lumen diameter of support member 150, the
extending portion of cylinder 135 is slidably disposed within the
support member 150 inner lumen.
[0169] Wire 132 extends proximally from cylinder 135 within support
member 150, as shown in FIGS. 12 and 13. A segment of wire 132
within support member 150 is secured to support member 150 at point
152. Wire 132 may be secured to support member 150 by any means
known to those of skill in the art, including use of adhesives,
crimping, soldering or welding. Because wire 132 is secured to
support member 150, the application of longitudinal forces on
support member 150 results in movement of sealing member 130 within
lumen 140, to open or close the valve, as described above with
respect to FIGS. 9-11B. Advantageously, use of support member 150
protects wire 132 from undesirable kinking or bending when sealing
member 130 is moved.
[0170] As illustrated in FIGS. 12 and 13, sealing member 130 has
movement-force increasing structure which increases the force
required to move sealing member 130 within lumen 140. The
movement-force increasing structure consists of waves 138 formed in
wire 132 just proximal to sealer portion 136. Waves 138 contact the
inner surface of lumen 140, thereby increasing the frictional
forces which must be overcome to move wire 132 within lumen 140. In
one preferred embodiment, where wire 132 is made of nitinol and has
an outer diameter of 0.006 inches, and is inserted into a nitinol
catheter which has an inner lumen 140 with the diameter of about
0.010 inches, waves are formed on wire 132 for one and one-half
cycles with an amplitude of about 0.016 inches to increase the
valve-opening movement force.
[0171] Referring to FIGS. 14 and 15, there is illustrated another
embodiment of the present invention. Referring to FIG. 14, there is
provided a catheter 400 having a tubular body 418 and inflatable
balloon (not shown) as described above. Catheter 400 may be formed
of materials and methods as described above, and may have
structural aspects identical to those described previously, except
where otherwise noted. In particular, as shown in FIGS. 14 and 15,
catheter 400 is not provided with a side-access port on the
catheter tubular body, nor is there provided cooperating positive
stops on the wire and lumen. Instead, the sealer portion may be
fully withdrawn from the lumen. Once the sealer portion is removed,
the proximal opening serves as an access port for attached devices
to inflate or deflate the balloon. The sealer portion can be
inserted through the proximal opening into the lumen after balloon
inflation to maintain the balloon in the inflated state.
[0172] Catheter 400 has a proximal end 412, and a distal end (not
shown) to which is mounted an inflatable balloon. A central lumen
440 extends within tubular body 418 between the proximal and distal
ends. An opening 423 to lumen 440 is present at the proximal end
412 of catheter 400.
[0173] A sealing member 430 is inserted into lumen 440 through
opening 423. Sealing member 430 has a main shaft 433, a tapering
region 431, and a wire 432. Sealing member 430 may be formed of
materials and by methods as described previously. As illustrated in
FIGS. 14 and 15, the outer diameter of main shaft 433 is less than
the inner diameter of lumen 440, such that main shaft 433 is
slidably insertable into lumen 440. In addition, the outer
diameters of tapering region 431 and wire 432 are also smaller than
main shaft 433, and thus lumen 440, such that tapering region 431
and wire 432 are also slidably insertable in lumen 440. A portion
of main shaft 433 preferably extends proximally from end 412, to
facilitate application of moving forces upon sealing member 430 to
move wire 432 within lumen 440, as described previously.
[0174] As illustrated in FIGS. 14 and 15, sealing member 430 has
movement-force increasing structure which increases the force
required to move sealing member 430 within lumen 440. The
movement-force increasing structure consists of waves 438a and 438b
formed in wire 432 near its distal end. Waves 438a and 438b contact
the inner surface of lumen 440, thereby increasing the frictional
force which must be overcome to move wire 432 within lumen 440. In
one preferred embodiment, where wire 432 is made of nitinol and has
an outer diameter of 0.006 inches, and is inserted into a nitinol
catheter which has an inner lumen 440 with a diameter of about
0.010 inches, waves are formed on wire 432 for 11/2 cycles with an
amplitude of about 0.016 inches to increase the valve-opening
movement force.
[0175] A lumen sealer portion 436 is coaxially and fixedly mounted
on wire 432. Sealer portion 436 forms a fluid tight seal with the
outer diameter of wire 432 and the inner diameter of lumen 440,
such that fluid introduced into lumen 440 through opening 423 is
prevented from flowing past sealer portion 436 when sealer portion
436 is inserted into lumen 440. Sealer portion 436 forms the fluid
tight seal by firmly contacting the entire inner circumference of a
section of lumen 440 along a substantial portion of the length of
sealer portion 436, and may be formed of materials and by methods
as previously described.
[0176] In some removable sealing member embodiments, the sealing
member is not provided with a separate sealing portion, as
described above. In these embodiments, the sealing member itself
functions as a sealing portion which is inserted into the proximal
opening to restrict fluid flow, and which may be partially or
wholly removed to provide for a fluid pathway between the proximal
opening and an expandable member on the distal end of the catheter.
Preferably, the sealing members of these embodiments comprise a
tapering rod, which at its distal end, has an outer diameter
smaller than the inner lumen diameter of the catheter in which it
is inserted as a plug, such that the distal end of the rod may be
easily inserted into the catheter lumen through the proximal
opening. The tapering rod increases in outside diameter at points
proximal to the distal end. Consequently, one or more points of the
rod have an outside diameter greater than the inner lumen diameter
of the catheter in which it is inserted as a plug, such that by
forcing the rod into proximal opening, the larger outer diameter of
the rod forms a relatively fluid tight seal with the catheter lumen
at the proximal opening of the catheter. An O-ring, or other
polymeric structure, may be mounted in the inner lumen of the
catheter at or near the proximal opening, to cooperate with the
tapering rod in the creation of the seal. Thus, in this embodiment,
the point where the seal is created does not move with respect to
the catheter, but is instead stationary at or near the proximal
opening of the catheter.
[0177] Referring to FIG. 20, there is depicted an alternative
embodiment of the valve the present invention. The alternative
embodiment is provided to a catheter 500, formed of a tubular body
518 and having a proximal end 512. Catheter 500 has an opening 523
at is proximal end, and a lumen 540 extending the length of the
tubular body. Lumen 540 is in fluid communication with an
expandable member (not shown) mounted on the distal end of tubular
body 518. A side-access port 522 is provided in tubular body 518 at
a point distal to proximal end 512. Catheter 500 may have aspects
identical, both in structure, dimensions, materials, and
construction, to catheters described previously.
[0178] A sealing member 550 is positioned within lumen 540 near
proximal opening 523 and side-access port 522. Sealing member 550
is formed from a short tubular body 568, having a lumen 590, which
is sealed at end 562, but open at the other end. Sealing member 550
has, an outer diameter slightly larger that the inner diameter of
lumen 540, but smaller than the outer diameter of tubular body 518,
such that sealing member 550 may be tightly fit within lumen 540
through opening 523, to form a fluid tight seal over catheter
proximal opening 523. Cooperating stopping structures (not shown)
may be provided to sealing member 550 and catheter 500 to prevent
removal of sealing member 550 from lumen 540 at elevated pressures.
Sealing member 550 may be formed out of the same materials as
tubular body 518.
[0179] Tubular body 568 is provided with an opening 572 extending
therethrough. Opening 572 is positioned on tubular body 568 such
that opening 572 is capable of aligning with side-access port 522
when sealing member 550 is rotated within lumen 540, or is moved
proximally or distally within lumen 540. A rotation element 595,
such as a perpendicular attachment, may be provided facilitate
rotation of sealing member 550 within lumen 540. Other rotation
elements, such as notches or grooves, may be used in place of the
perpendicular attachment, as will be appreciated by those of skill
in the art.
[0180] Sealing member 550 functions as a valve within catheter 500,
controlling fluid flow through side-access port 522. When sealing
member 550 is rotated so that port 522 and opening 572 are aligned,
fluid may flow through port 522 through lumen 540 to inflate the
occlusive device. Upon the desired inflation, sealing member 550
may be rotated, as for example by ninety degrees, or moved
proximally or distally within lumen 540, such that opening 572 is
no longer aligned with port 522, and tubular body 568 blocks fluid
flow through port 522.
[0181] Shown in FIG. 21, is an alternative embodiment of the
rotatable sealing member. Numerals corresponding to those of the
embodiment of FIG. 20 have been used to illustrate the similar
structural aspects between the two embodiments. Sealing member 650
is identical in construction to the sealing member of FIG. 20,
except that sealing member 650 is somewhat larger, and is adapted
to be slipped over tubular body 618. The respective diameters of
tubular body 618 and sealing member lumen 690 are such that a fluid
tight seal is created over lumen 623. Side-access inflation port
622 may be aligned with opening 672, as above, by rotation or
longitudinal movement, to provide fluid access to lumen 640 through
port 622.
[0182] In certain embodiments, it may be desirable for sealing
members 550 and 650 to have a longer length, such that they may
function as an extension for other catheters to be inserted over
catheters 500 and 600. In these embodiments, sealing members 550
and 650 may be formed with longer tubular bodies, or be provided
with attachments so that extension members may be releasably
secured thereto.
[0183] Referring to FIGS. 22, 23A and 23B, there is illustrated an
alternative embodiment of the present invention featuring a
self-closing valve. The alternative embodiment comprises a catheter
700 having an elongate flexible tubular body 718 extending between
a proximal control end 712 and a distal functional end (not shown),
and having a balloon (not shown) as described previously. Tubular
body 718 has central lumen 740 which extends between the proximal
and distal ends. Lumen 740 has an opening 723 at proximal end 712,
and is sealed fluid tight at the distal end. A side access
inflation port 722 is formed in tubular body 718 at a point distal
of opening 723. Inflation port 722 and lumen 740 are in fluid
communication with the distal inflatable balloon, as described
previously.
[0184] A wire 732 is inserted into opening 723, and is slidably
disposed within lumen 740. Accordingly, the outer diameter of the
wire 732 must be less than the inner diameter of lumen 740, so that
wire 732 may be slidably accommodated therein. A sealer portion 736
is coaxially mounted on wire 732. Sealer portion 736 is of similar
type and construction to the sealer portion described in connection
with FIGS. 9-11B. Sealer portion 736 is positioned on wire 732 at a
point distal to inflation port 722, and forms fluid-tight seal with
the outer diameter of wire 732 and the inner diameter of lumen 740,
such that fluid introduced into lumen 740 is prevented from flowing
past sealer portion 736. Consequently, because sealer portion 736
is positioned with lumen 740 distal to inflation port 722, sealer
portion 736 is in the valve-closed position.
[0185] In the embodiment depicted in FIGS. 22-23B, tubular body 718
is formed from a material having a certain degree of elasticity,
such that if the proximal end 712 of tubular body 718 is secured to
wire 732 at point 750, and a longitudinal force is applied to
tubular body 718 in a direction distal to end 712, the elasticity
of tubular body 718 results in the shifting of inflation port 722
in the distal direction. Moreover, slits 711 may be formed in
tubular body 718 near proximal end 712 to enhance the elastic
response of tubular body 718, thereby increasing the distal
translocation of inflation port 722 upon application of an axial
force to tubular body 718. Wire 732 may be secured to tubular body
718 by any means known to those of skill in the art, such as
adhesives, welding, soldering, or crimping.
[0186] In a preferred embodiment, tubular body 718 is made out of
nitinol, and has at least 8% elasticity when longitudinal slits 711
are introduced at the proximal end. As can be observed in FIG. 23A,
in the absence of any longitudinal force applied to tubular body
718, sealer portion 736 is positioned within lumen 740 at a point
distal to inflation port 722, such that fluid may not pass through
port 722 to inflate or deflate the balloon. However, if a
longitudinal force is applied to tubular body 718 in the distal
direction, and the proximal end of tubular body 718 and wire 732
are held in position, tubular body will stretch, as shown in FIG.
23B, and inflation port 722 will be translocated in the distal
direction so that sealer portion 736 will be located within the
lumen proximally of port 722. This will establish an unrestricted
fluid pathway between inflation port 722 and the distal balloon, so
that the balloon may be either inflated or deflated by passage of
fluid through port 722. Upon removal of the longitudinal force, the
elastic response of tubular body 718 will result in proximal
translocation of inflation port 722, and sealer portion 736 will
once again be in the valve-closed position.
[0187] Referring to FIG. 16 and 17A, there is illustrated an
inflation adaptor 200 which may be used to inflate and to open and
close the low profile valve depicted in FIGS. 9-13. Inflation
adaptor 200 comprises a housing having a first half 202 and a
second half 204, which are preferably formed of metal, medical
grade polycarbonate, or the like. Halves 202 and 204 are attached
to one another by a pair of hinges 205 positioned on one of the
lateral edges of each half, such that halves 202 and 204 may be
separated or joined in a clam shell manner as depicted in FIGS. 16
and 17. A locking clip 230 secures half 202 to half 204 while
inflation adaptor 200 is in use. Locking clip 230 may be provided
with an angled leading edge 235 to facilitate closing of clip 230
to secure halves 202 and 204 together. Springs 209 may also be
provided to facilitate opening of adaptor 200.
[0188] A groove 240 separates first half 202 from second half 204
when the halves are closed and clip 230 is secured. Groove 240 is
of sufficient width to accept the proximal end of a catheter having
the low profile valve, as described in detail above. A fitting 210
is positioned on half 202, to create an inflation passageway 212
which terminates in opening 285 on the interior surface of first
half 202. Fitting 210 is preferably a standard luer connector which
may be attached to a variety of existing external pressurized fluid
sources, although other types of fittings, such as tubings, quick
connects, and Y-site connections, may be easily substituted for a
luer fitting.
[0189] A seal comprising a pair of gaskets 280 is positioned around
opening 285 on the interior surfaces of halves 202 and 204. Gaskets
280 are in alignment, such that when halves 202 and 204 are brought
together and secured by locking clip 230, a fluid tight inflation
chamber is created within the interior region defined by gaskets
280. The fluid tight inflation chamber is in fluid communication
with fitting 210 via inflation passageway 212, so that a
pressurized inflation fluid may be introduced into the fluid tight
inflation chamber by attaching an external pressurized fluid source
to fitting 210. Moreover, gaskets 280 are preferably formed of
resilient materials, such as silicone, C-Flex.TM. and Pebax.TM., so
that gaskets 280 may form-fit over a catheter tubular body which
extends across the lateral edges of gaskets 280, to create the
fluid tight chamber.
[0190] An actuator 220 is positioned on the external surface of
half 202. In the embodiment illustrated in FIGS. 16 and 17,
actuator 220 controls a cam which operates a sliding panel 283 on
the interior surface of half 202. Sliding panel 283 moves back and
forth along a line which bisects opening 285. When actuator 220 is
moved to a first position, sliding panel 283 moves toward opening
285 along this line. When actuator 220 is moved to a second
position, sliding panel 283 moves away from opening 285 along the
same line. A corresponding sliding panel 284 is positioned on half
204, such that panels 283 and 284 are aligned and move together
when the position of actuator 220 is changed. To facilitate
coordinated movement of panels 283 and 284, a pin 286, or such
other similar engagement structure, may be provided to releasably
secure panel 283 to panel 284 when the adaptor is closed. The
length of travel of panels 283 and 284 is preferably adjusted to
provide the minimum sufficient distance to position the sealing
member in the valve open or valve closed position, as desired.
[0191] Panels 283 and 284 each have a roughened surface 290, to
facilitate the frictional engagement of panels 283 and 284 with the
main shaft portion of the low profile valve. In a preferred
embodiment, panels 283 and 284 are both made of silicone, and
roughened surface 290 comprises teeth 291 and grooves 292 formed on
each of panels 283 and 284. The teeth 291 and grooves 292
cooperate, to permit the teeth of one panel to fit into the grooves
of the opposite panel when the adaptor is closed.
[0192] For ease of understanding, the operation of inflation
adaptor 200 to inflate the balloon of the catheter of FIGS. 9-11B
will now be described. Actuator 220 is moved to the first position,
so that sliding panels 283 and 284 are moved closer to opening 285.
Locking clip 230 is then undone, exposing groove 240. Halves 202
and 204 are then partially separated, and catheter 10, with the
balloon 20 deflated, is inserted into the inflation adaptor. As
described previously, catheter 10 has an inflation port 22 located
near proximal end 12, and a main shaft 33 extending from proximal
end 12. Catheter 10, with the low profile valve in the closed
position, is placed within groove 240 of partially open adaptor
200, and catheter 10 and main shaft 33 are placed within securing
clips 271 and 272, such that when halves 202 and 204 are closed,
inflation port 22 will lie within the fluid tight inflation chamber
created by gaskets 280, and the extending portion of main shaft 33,
but not proximal end 12, will rest between sliding panels 283 and
284. An alignment slot 298 and overlying shelf 299 may be provided
to facilitate alignment and prevent buckling or kinking of the
catheter and sealing member during use.
[0193] As shown in FIG. 17B, in one embodiment, indicia 260 are
provided on catheter 10 and main shaft 33, which when aligned with
indicia 270 on inflation adaptor 200, result in alignment of
inflation port 22 with the fluid tight inflation chamber of adaptor
200, and alignment of main shaft 33 with sliding panels 283 and
284, when catheter 10 and sealing member 30 are inserted into
groove 240. Indicia 260 and 270 may take the form of markings,
grooves or notches, or any other suitable means of aligning the
valve with the inflation adaptor alignment indicia, may be
provided. Preferably, the gap between indicia 260 on catheter 10
and main shaft 33 is approximately equal to the space between clips
271 and 272, such that by placing indicia 260 within clips 271 and
272, catheter 10 and main shaft 33 are properly aligned within
adaptor 200.
[0194] Indicia solely on the catheter tubular body may also be used
to facilitate correct alignment. For example, two visible markings
may be place on the catheter on either side of the catheter
inflation access port. By inserting the catheter into lower half
204 so that both of these markings are place within lower half
gasket 280, the catheter inflation access port will be within the
fluid tight inflation chamber created by gaskets 280 when halves
202 and 204 are secured to one another.
[0195] Once main shaft 33 and inflation port 22 are properly
aligned within adaptor 200, locking clip 230 is secured. Inflation
port 22 now lies within the fluid tight inflation chamber created
by gaskets 280, and main shaft 33 rests between sliding panels 283
and 284. The clinician may then attach an external pressurized
fluid source to fitting 210.
[0196] To inflate balloon 20, the clinician moves actuator 220 from
the first position to the second position, thereby causing sliding
panels 283 and 284 to move away from opening 285. Because main
shaft 33 is firmly secured between panels 283 and 284, a
longitudinal force directed away from proximal end 12 is applied to
main shaft 33. The longitudinal force on main shaft 33 results in
wire 32 being partially withdrawn from lumen 40, which causes
sealer portion 36 on wire 32 to be moved to a position within lumen
40 which is proximal of inflation port 22. The movement of sealer
portion 36 proximally of inflation port 22 opens the low profile
valve, by establishing an unrestricted fluid pathway between
inflation port 22 and balloon 20.
[0197] The external pressurized fluid source may then be activated,
as for example by pushing the plunger on a syringe, such that
pressurized fluid passes through passageway 212 and opening 285
into the fluid tight inflation chamber. The pressurized fluid then
passes through inflation port 22 and lumen 40, to inflate balloon
20.
[0198] Inflated balloon 20 may be maintained in the inflated state,
in the absence of the pressurized fluid source, by closing the low
profile valve. This is accomplished by moving actuator 220 back to
the first position, thereby causing sliding panels 283 and 284 to
move toward opening 285. The moving panels apply a longitudinal
force, directed toward proximal end 12 to main shaft 33, causing
wire 32 to be further inserted into lumen 40. Consequently, sealer
portion 36 is moved from a position, within lumen 40 which is
proximal to inflation port 22 to a position in lumen 40 which is
distal to inflation port 22. The fluid tight seal created by sealer
portion 36 traps the pressurized fluid within lumen 40 and balloon
20, thereby maintaining balloon 20 in the inflated state. The
external pressurized fluid source may then be deactivated and
removed. Once the low profile valve is closed, inflation adaptor
200 may be removed by unlocking clip 230, and removing catheter 10
and main shaft 33 from groove 240.
[0199] Referring to FIGS. 18 and 19, there is illustrated an
alternative embodiment of an inflation adaptor especially adapted
for manipulating removable low profile valves, although it may be
used with side-access embodiments as well. Moreover, it should also
be appreciated that adaptor 200 and similar type adaptors may also
be used to manipulate removable valve embodiments.
[0200] Adaptor 300 comprises an outer sleeve 320 formed of metal,
medical grade polycarbonate, or similar such materials. Outer
sleeve 300 defines a tapering inner lumen 350. Lumen 350 tapers
from large diameter 352 which is significantly greater than the
outer diameter of the catheter tubular bodies inserted into lumen
350, to a smaller diameter 355, which is slightly larger the outer
diameter of the catheter tubular body. Lumen 350 is in fluid
communication with an inflation passageway 312 formed by fitting
310, so that a pressurized inflation fluid may be introduced into
lumen 350. Releasable seals 315 are positioned at each end of lumen
350, such as to create a fluid tight inflation chamber within lumen
350 when a pressurized fluid source is attached. Releasable seals
350 may comprise any type of seal known to those of skill in the
are, such as Toughy Borst connectors, hemostatic valves, and the
like. Releasable seals 350 may also act to secure any catheters and
sealing members inserted within the releasable seal openings
325
[0201] In use, a catheter and sealing member, such as that
described in connection with FIGS. 14-15, is inserted into opening
325 after seals 315 have been opened. The catheter and sealing
member are positioned under passageway 312, and the sealing member
is removed from the proximal opening of the catheter. A fluid
passageway is thereby created between the proximal catheter opening
and the expandable member of the distal end of the catheter. Seals
350 are closed to create a fluid tight chamber, and a vacuum and/or
pressurized inflation fluid is applied, to inflate or deflate the
balloon. After the desired inflation or deflation has occurred, the
sealing member may be introduced into the proximal opening of the
catheter tubular body to seal the lumen, either by hand or by a
movable actuator (not shown). Seals 350 may then be loosened, and
the end access adaptor 300 removed by sliding the adaptor off the
end of the catheter and sealing member.
[0202] Referring to FIGS. 24-26B, there is illustrated an
alternative embodiment inflation adaptor 800 which may also be used
in conjunction with the low profile valves of the present
invention, of the type depicted in FIGS. 9-13, to inflate or
deflate catheter balloons. Inflation adaptor 800 comprises a
housing having a first half 802 and a second half 804, which are
preferably formed of a medical grade polycarbonate. However, as
will be appreciated by those of skill in the art, a great many
other materials may by used to form adaptor 800, including metals
such as 300 series stainless steel and 400 series stainless steel,
and polymeric materials such as Acrylonitrile-butadiene-- styrene
(ABS), Acrylics, and Styrene-acrylonitriles. Furthermore, the
individual halves 802 and 804 may be manufactured in a variety of
different ways. For example, where polymeric materials are used, it
is preferable to use a mold to manufacture each of the halves.
Moreover, in some embodiments, more than one molded piece may be
used to form an individual half, with the various pieces being
joined together by bonding or mechanical means to form a half.
Alternately, as is known in the art, the individual halves can be
formed through machining processes performed on larger blocks of
the raw materials.
[0203] Halves 802 and 804 are attached to one another by hinges 806
positioned on one of the lateral edges of each half, through which
a joining pin 805 is inserted, such that halves 802 and 804 may be
opened or closed in a clam shell manner as depicted in FIGS. 24 and
25. Preferably, the cross-sectional angle formed by halves 802 and
804 in the open position, as shown in FIG. 25, is 90.degree. or
greater, and more preferably from 120.degree.-180.degree., to
facilitate insertion of a catheter into adaptor 800.
[0204] As shown in FIGS. 24 and 25, a plate 832 is secured to the
front portion of housing half 804 by three screws 833. Plate 832 is
provided with two or more pin receptacles 834. A cam latch 830 is
mounted on plate 832 and is secured thereto by pin 831 which runs
through pin receptacles 834 and a corresponding cam latch pin
receptacles 836, to form a hinge between cam latch 830 and plate
832. Cam latch 830 and plate 832 may be made from any of the same
variety of materials as housing halves 802 and 804, and for any
particular embodiment, are preferably made of identical materials,
although combinations of materials may also be used. Also, as is
appreciated by those of skill in the art, the corresponding hinge
structure provided by plate 832 and cam latch 830 may also be
achieved by many other methods. For example, plate 832 may be
integrally molded with housing half 804 at the time of manufacture
as a single piece, thereby eliminating the need for screws 833, but
with cam latch 830 mounted thereon as described above.
[0205] Cam latch 830 is designed to secure halves 802 and 804
together when adaptor 800 is in use, to assist in the creation of
an the inflation seal as described above. Advantageously, by
placing cam latch on half 804 as shown, the adaptor interior is
more accessible to the clinician during a procedure, and it is
easier for the clinician to insert catheters into adaptor 800. Cam
latch 830 also serves the important function of preventing
accidental opening of the adaptor 800 during use. An important
feature of cam latch 830 is the manner in which it cooperates with
housing half 802 to create a releasable locking mechanism which
applies great force to halves 802 and 804 upon closing, while at
the same time using the principles of mechanical advantage to
minimize the force the user must exert to close cam latch 830. This
is achieved by providing latch 830 with a cammed surface 838 and
also providing the front edge of housing half 802 with a rounded
lip 837 to accept cammed surface 838, as shown in cross-sectional
schematic form in FIGS. 27A-27C.
[0206] Referring to FIG. 27A, halves 802 and 804 have been brought
together, with cam latch 830 in its open position. As cam latch 830
begins to be closed, as shown in FIG. 27B, cammed surface 838
contacts rounded lip 837 and exerts a closing force thereon. Upon
further closing, and to the fully closed position shown in FIG.
27C, cam latch 830 acts as a lever, with the closing force between
cammed surface 838 and lip 837 being a function of the force of
exerted by the user, the length of the lever (length of cam latch
door), and the height of the cam surface, as defined by the
following well known mathematical equation: 1 F u = F c H L
F.sub.u=User applied force
F.sub.c=Closing force
L=length of lever (width of door)
H=height of can
[0207] However, as can be appreciated, because the lever length,
which in the adaptor embodiment is the length of cam latch 830 in
its closing direction, is much greater than the height of the cam
created by surface 838 and lip 837, the closing force exerted is
always greater than the force the user exerts on cam latch 830.
Thus, very tight seals may easily be created by the clinician when
the device is used.
[0208] Cam latch 830 is also preferably provided with a shelf 835
to secure halves 802 and 804 together. Shelf 835 is positioned on
latch 830 at a point such that when latch 830 is in its closed
position, shelf 835 firmly contacts housing half 802 along the side
bearing hinges 806. Preferably, shelf 835 has an angled leading
edge to facilitate closing of latch 830.
[0209] A gap 840 separates first half 802 from second half 804 when
the halves are closed and latch 830 is secured. Gap 840 is of
sufficient width to accept the proximal end of a catheter having
the low profile valve, as described in detail above, without
crimping the catheter to impair its function. A fitting 810 is
positioned on half 802, to create an inflation passageway 812 which
terminates in opening 885 on the interior surface of first half
802. Fitting 810 is preferably a standard luer connector which may
be attached to a variety of existing external pressurized fluid
sources, although other types of fittings, such as tubings, quick
connects, and Y-site connections, may be easily substituted for a
luer fitting.
[0210] A seal comprising a pair of gaskets 880 is positioned around
opening 885 on the interior surfaces of halves 802 and 804. Gaskets
880 are in alignment, such that when halves 802 and 804 are brought
together and secured by cam latch 830, a fluid tight inflation
chamber is created within the interior region defined by gaskets
880. The fluid tight inflation chamber is in fluid communication
with fitting 810 via inflation passageway 812, so that a
pressurized inflation fluid may be introduced into the fluid tight
inflation chamber by attaching an external pressurized fluid source
to fitting 810. Gaskets 880 are preferably formed of resilient
materials, such as silicone, C-Flex.TM. and Pebax.TM. or
Kraton.TM., silicone, and other elastomeric materials, so that
gaskets 880 may form-fit over a catheter tubular body which extends
across the lateral edges of gaskets 880, to create the fluid tight
chamber.
[0211] An actuator 820 is positioned on the external surface of
half 802. In the embodiment illustrated in FIGS. 24-26B, actuator
820 is a rotatable knob controlling a cam which operates a sliding
panel 883 on the interior surface of half 802. As will be
appreciated by those of skill in the art, however, a great many
different actuating structures other than rotatable knobs and
sliding panels may be used to achieve the movement of the catheter
sealing members described herein. Furthermore, where catheter
valves require rotational movement, such as those of FIGS. 20 and
21, rotational actuating mechanisms may be provided as well.
[0212] Sliding panel 883 moves back and forth along a line which
bisects opening 885. When actuator 820 is moved to a first
position, shown in FIG. 26A, sliding panel 883 moves away from
opening 885 along this line. When actuator 820 is moved to a second
position, as shown in FIG. 26B, sliding panel 883 moves toward
opening 885 along the same line. A corresponding sliding panel 884
is positioned on half 804, such that panels 883 and 884 are aligned
and move together when halves 802 and 804 are closed and the
position of actuator 820 is changed.
[0213] In actual clinical practice, the movement of panels 883 and
884 results in the opening and closing of a catheter valve placed
within adaptor 800. When actuator 820 is moved to the position
shown in FIG. 26A, panels 883 and 884 move away from opening 885.
This would result in the opening of the valve described in
connection with FIGS. 9-13, as the sealer portion of the valve
would be positioned proximally of the access port to establish a
fluid pathway between the access port and the inflatable balloon at
the distal end of the catheter. Conversely, when actuator 820 is
moved to the position shown in FIG. 26B, panels 883 and 884 move
toward opening 885. This would result in the closing of the valve,
as the sealer portion of the valve would be positioned distally of
the access port, thereby preventing substantially all fluid flow
between the access port and those portions of the catheter distal
to the sealer portion. Preferably, detents (not shown) are provided
on the actuator camming mechanism to provide the user with tactile
and audible feedback when the panels are nearest or farthest from
opening 885 (i.e., catheter valve is closed or open,
respectively).
[0214] Adaptor 800 is also preferably provided with a safety lock,
to prevent accidental opening when the adaptor is being used and
the catheter valve is open. As shown in FIGS. 26A and 26B, this may
be achieved by providing an extending flanged portion 822 to
actuator knob 820. When actuator knob 820 is in the valve open
position, as shown in FIG. 26A, extending flange 822 extends over
latch 830, preventing the latch from being opened. In the valve
closed position, as shown in FIG. 26B, flange 821 is rotated away
from latch 830, which may then be opened.
[0215] Panels 883 and 884 each have a roughened surface 890, to
facilitate the frictional engagement of panels 883 and 884 and
their coordinated travel with the moving portions of the low
profile valve. Panels 883 and 884 may be made from any of a variety
of polymeric or metallic materials, but must possess sufficient
frictional force to engage and move the catheter sealing member
without slippage. Consequently, depending on the type of catheter
used, those of skill in the art may desire to select different
materials for panels 883 and 884 to maximize the frictional forces
between the panels and their intended use catheter. In a preferred
embodiment, in which panels 883 and 884 are to engage a catheter
sealing member made from stainless steel, panels 883 and 884 are
both made of Kraton 90A.TM., and roughened surface 890 comprises
teeth 891 and grooves 892 formed on each of panels 883 and 884. The
teeth 891 and grooves 892 cooperate, to permit the teeth of one
panel to fit into the grooves of the opposite panel when the
adaptor is closed. Furthermore, alternative cooperating structure,
such as dimples and ridges, may also be used to coordinate travel
of panels 883 and 884.
[0216] One problem that has been recognized with low profile valves
is the phenomenon of plug walk-out. That is, after the valve has
been placed in its closed position, with the sealer portion of the
sealing member distal to the inflation access port, and the adaptor
removed, the internal forces on the sealing member tend to cause
very small portions of the sealing member to be pushed out of the
catheter proximal end. Plug walk out is undesirable as it has an
adverse impact on the ability of the sealed catheter to act as a
guidewire for other devices. It has been found, however, the plug
walk out can be minimized or eliminated if the sealing member is
initially "overdriven", or forced slightly further in the catheter,
during the sealing step.
[0217] Advantageously, adaptor 800 is provided with an overdrive
system to overdrive a sealing member into a catheter. Referring to
FIG. 25, panel 884 travels back and forth within housing recess 894
along a which bisects opening 885, as described above. A spring 809
is mounted in recess 894 and is attached to the wall of recess 894
and panel 884. Spring 809 is biased so as to push panel 884 toward
opening 885, and forces panel 884 against the wall of recess 894
which is opposite to that which spring 809 is attached.
[0218] Referring to FIGS. 28A-28C, there is shown the top portion
of half 802 containing panel 883. Panel 883 resides in housing
recess 893, and travels back and forth along a line which bisects
opening 885, as described above. The movement of panel 883 is
controlled by actuator 820, as described above. An expanded spring
888 is attached to panel 883, as shown in FIGS. 28A-28C. Spring 888
has a strength which exceeds that of lower spring 809. In the
adaptor open position, as shown in FIG. 25, expanded spring 888
contacts the wall of recess 893, and pushes panel 883 away from the
recess wall to create an overdrive gap 886, as shown in FIG.
28A.
[0219] When a catheter with a valve in a closed position is loaded
into half 804, and halves 802 and 804 are closed and latched, the
teeth 891 of panel 883 contact the grooves of panel 884. The
superior spring force of spring 888 then forces spring 809 to
compress a small amount, such that panel 884 no longer is forced
against the recess wall, and now has an overdrive gap (not shown)
approximately equal to overdrive gap 886. The actuator may then be
engaged to drive panels 883 and 884 away from opening 885 toward
recess walls 893a and 894a, respectively, thereby opening the valve
mechanism. The inflatable balloon on the catheter may then be
inflated as described above.
[0220] Upon closure of the valve, by rotating actuator 820 in the
opposite direction, panels 883 and 884 are moved toward opening 885
until the sealer portion of the sealing member is distal to the
catheter inflation access port. Overdrive of the sealing member is
then achieved when actuator 820 is adjusted so that panels 883 and
884 are forced against recess walls 893b and 894b, as shown for
panel 883 in FIG. 28C. That is, the force of actuator 820 overcomes
the force of spring 888, and drives the sealing member into the
catheter by a distance farther than it initially resided before the
valve was opened, the distance being approximately equal to the
width of gap 886. It has been found that by overdriving the sealing
member to a closed position further than its initial closed
position compensates for plug walk-out. Preferably, the sealing
member is overdriven by a distance of about 0.020 inches.
[0221] Alternative overdrive mechanisms may be used for other
adaptor embodiments. For example, rather than mounting spring 888
on panel 883, the spring might be mounted in a slot wall 893b, with
a plunger (not shown) attached to panel 883 and aligned with the
spring. In its unforced state, the spring would exert force on the
plunger, pushing panel 883 away from wall 893a to create overdrive
gap 896. However, as before, the actuator mechanism 820 could be
used to overcome the spring force in the valve closing cycle,
thereby creating the overdrive. Numerous other overdrive mechanisms
may also be employed, as will be appreciated by those of skill in
the art.
[0222] As illustrated in FIG. 25, adaptor 800 is also provided with
immovable pads 870 on both halves 802 and 804. Pads 870 function to
secure the catheter within adaptor 800 when it is closed, and to
prevent movement of the catheter during valve opening and valve
closing procedures. Accordingly, the material used for pads 870 is
selected to have a high degree of frictional force with respect to
the surface of the catheter body to which pads 870 will contact. A
wide variety of polymeric and metallic materials are thus suitable
to form pads 870 such as Kraton.TM., C-Flex.TM. or Pebax.TM.. In
one embodiment, pads 870 are integrally molded with halves 802 and
804 out of medical grade polycarbonate, and are intended to contact
a catheter tubular body formed from nitinol.
[0223] It is also preferred that half 804 be provided with guiding
means to facilitate correct positioning of the catheter into the
adaptor. For the embodiment illustrated in FIG. 25, these guiding
means consist of two or more clips 896 to facilitate positioning of
a catheter into the adaptor. Clips 896 are provided with grooves
897 in which the catheter is inserted and secured prior to closure
of adaptor 800. Clips 896 may be formed of any material flexible
enough to be capable of releasably securing the catheters to be
used in adaptor 800. In one preferred embodiment, clips 896 are
formed of C-Flex 70A.TM.. On half 802, and aligned with clips 896,
there are provided recesses 895, to accept clips 896 when halves
802 and 804 are brought together and closed. Preferably, alignment
indicia on the catheters to be used with adaptor 800 coincide with
the spacing of clips 896, so that by placing the catheter portion
bearing the indicia directly in clips 896, the catheter is properly
inserted in the adaptor with its inflation access port contained in
the fluid tight inflation chamber created by gaskets 880 upon
closure of adaptor 800. A projecting ridge 875 may also be provided
to facilitate placement of the catheter, and direct its orientation
during placement in the adaptor so that alignment is proper.
[0224] Alternately, other guiding means may be used as well. For
example, clips 896 may comprise one or more magnetic elements which
cooperate with gold-plated stainless steel rings (or other plated
ferromagnetic substances) incorporated into the catheter tubular
body to guide the catheter into the correct alignment position.
[0225] In one preferred embodiment, as shown in FIG. 25, halves 802
and 804 are also provided with projecting shelves 898 and 899,
respectively, which come together when halves 802 and 804 are
closed to form a slot therebetween in which the catheter resides.
Advantageously, the slot created by shelves 898 and 899 acts to
provide reinforcement to a catheter used in adaptor 800 during the
valve opening and closing procedures, and helps to prevent buckling
or kinking of the catheter tubular body when panels 883 and 884 are
moved to open or close the catheter valve.
[0226] In clinical practice, there is a direct correlation between
the distance that panel 884 moves and the distance moved by the
sealer portion of a catheter valve when adaptor 800 is used.
Consequently, a controlled and known movement of panel 884 over a
set direction and distance results in a movement of the valve
sealer portion in the same direction and for substantially the same
distance. Thus, with a controlled movement adaptor such as adaptor
800, there is no need to require a catheter having positive
cooperating stops to prevent removal of the sealer portion from the
catheter, as was described for the catheter of FIGS. 9-13. The
adaptor itself prevents accidental withdrawal of the sealer portion
from the catheter, by precisely controlling the movement of the
sealer portion within the catheter.
[0227] Accordingly, in one preferred embodiment, adaptor 800 is
used with catheter 900, which lacks positive cooperating stops, and
is depicted in FIGS. 29 and 30. Catheter 900 has a tubular body 918
and inflatable balloon (not shown) as described above. Catheter 900
may be formed of materials and methods as described above, and may
have structural aspects identical to those described previously,
except where otherwise noted.
[0228] Catheter 900 has a proximal end 912, and a distal end (not
shown) to which is mounted an inflatable balloon. A central lumen
940 extends within tubular body 918 between the proximal and distal
ends. An opening 923 to lumen 940 is present at the proximal end
912 of catheter 900. A side-access port 922 in fluid communication
with lumen 940 is provided on tubular body 918.
[0229] A 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 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. 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 900
and may freely 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 0.0086 inches, and plug mandrel wire
has a diameter of about 0.005 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.
[0230] The length of sealing member region 935 extending proximally
of catheter 900 may vary in length depending upon the intended use
environment. For example, where catheter 900 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 900 and sealing member
region 935 be about 300 centimeters. Alternately, where catheter
900 is to be used in a single operator or rapid exchange
embodiment, it is preferred that the total length of catheter 900
and region 935 be about 180 centimeters. Accordingly, with a known
catheter length and use environment, an appropriate length for
region 935 may be chosen.
[0231] The elements of sealing member 930 may be formed of
materials and by methods as described previously. For example,
regions 935 and 933 and plug mandrel wire 932 may all be made out
of metals such a stainless steel. Alternately, 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
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.
[0232] 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 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.
[0233] As illustrated in FIGS. 29 and 30, 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 900. 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.
[0234] As illustrated in FIGS. 29 and 30, 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, where wire 932 is made of nitinol and has
an outer diameter of about 0.005 inches, and is inserted into a
nitinol catheter which has an inner lumen 940 with a diameter of
about 0.090 inches, waves are formed on wire 932 for 11/2 cycles
with an amplitude of about 0.016 inches to increase the
valve-opening movement force.
[0235] 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 side-access port
922 is prevented from flowing past sealer portion 936 when sealer
portion 936 is inserted into lumen 940 distally of side-access port
922. 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,
and may be formed of materials and by methods as previously
described.
[0236] As shown in FIG. 29, sealer portion 936 is positioned
proximally of side-access opening 922, so that an unrestricted
fluid passageway exists between port 922 and the inflatable balloon
at the distal end of catheter 900. This is the valve open position
described above. In this position, region 933 is shown partially
withdrawn from opening 923. Referring to FIG. 30, sealer portion
936 is positioned distally of port 922, so that fluid flow between
port 922 and the inflatable balloon at the distal end of catheter
900 are substantially blocked. This is the valve closed position
described above.
[0237] Catheter 900 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 900 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 900
be used with an adaptor such as adaptor 800, which provides for
such controlled precise movement.
[0238] 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. With respect to
adaptor 800, this is accomplished by selecting a recess 893
dimension which precisely defines the distance that sealing member
930 is to travel to achieve the valve open and valve closed
positions, without accidentally removing sealing member 930 from
opening 923. In one embodiment, where access port 922 is positioned
36 mm from opening 923, a stroke length of 5.5 mm was found to be
suitable.
[0239] III. Expansion Members
[0240] The expansion members discussed herein include braids,
coils, ribs, ribbon-like structures, slotted tubes, and filter-like
meshes. These expansion members may be partially covered or
completely surrounded by a membrane or other covering to provide
occlusion or sealing of the vessel. As used herein, "occlusion" or
"sealing", and the like, mean partial or complete blockage of fluid
flow in a vascular segment, as it is sometimes preferable to allow
perfusion. Moreover, such expansion members may be deployed by
various mechanical means, electrical means or thermomechanical
means, etc., as described herein. Expansion members that are
deployed mechanically are preferably "spring-like" in nature, i.e.
they are preferably resilient to facilitate their deployment or
retraction.
[0241] A. Catheter Apparatuses and Self-Expanding Braids
[0242] One embodiment of a catheter apparatus incorporating the
present invention for treating occluded vessels is shown in FIGS.
31 and 32. As shown therein, the catheter apparatus 1651 consists
of a flexible elongate member 1652 which is provided with proximal
and distal extremities 1653 and 1654. A conventional adaptor 1656
is mounted on the proximal extremity and is provided with a
Touhy-Borst fitting 1657 which is in communication with a large
central lumen 1658 extending from the proximal extremity 1653 to
the distal extremity 1654. An aspiration fitting 1661 is provided
on the adaptor 1656 as well as an irrigation fitting 1662, both of
which are in communication with the central lumen 1658. However, it
should be appreciated that if desired, separate lumens can be
provided in the flexible elongate member 652 for both of the
fittings 1661 and 1662.
[0243] Self-expanding sealing mechanism 1666 is mounted on the
distal extremity 1654. This self-expanding sealing mechanism 1666
can take any suitable form. For example, as shown it can consist of
a braided structure 1667 formed of a suitable shape memory material
such as a nickel titanium alloy that will attempt to expand to a
predetermined shape memory. Other than shape memory materials,
other materials such as stainless steel, Elgiloy.TM., titanium or
other materials can be utilized in the braid 1667 as long as they
have the capability of expanding when the self-expanding seal
mechanism is released. Also it should be appreciated that the
self-expanding seal mechanism 1666 can be comprised of an absorbent
material which when it absorbs saline or blood expands to form a
seal. Such seals can be readily accomplished because it is only
necessary to form a seal of approximately 1.5 psi to prevent small
particles from moving downstream.
[0244] In order to prevent abrasion of a vessel, it is desirable to
cover the braided structure 1667 with a covering 1668 of a suitable
material such as a polymer or a biocompatible coating which extends
over the braided structure 1667 and which moves with the braided
structure 1667 as it expands and contracts. The polymer can be of a
suitable material such as silicone, C-flex, polyethylene or PET
which would form a good sealing engagement with the wall of the
artery. The covering 1668 may be perforated to allow perfusion.
[0245] A mechanism is provided for compressing the self-expanding
sealing mechanism 1666 so that the apparatus can be inserted into
the vessel 1481 and consists of an elongate sleeve 1771 having
proximal and distal extremities 1772 and 1773 and a bore 1774
extending from the proximal extremity 1772 to the distal extremity
1773. A collar 1776 is mounted on the proximal extremity 1772 of
the sleeve 1771 and is positioned near the adaptor 1656. The collar
1776 serves as a mechanism for retracting the sleeve as shown in
FIG. 32 to uncover the self-expanding sealing mechanism 1666 after
the catheter has been deployed to permit the self-expanding sealing
mechanism 1666 to expand and form a seal with the arterial vessel
adjacent the stenosis to be treated.
[0246] Another embodiment of a catheter apparatus for treating
occluded vessels incorporating the present invention is shown in
FIGS. 33 and 34. As shown therein, the apparatus 1781 consists of a
guiding catheter 1782 having proximal and distal extremities 1783
and 1784. As shown, the distal extremity 1784 is provided with a
pre-formed bend of a conventional type. A conventional attachment
1786 is mounted on the proximal extremity 1783. Self-expanding seal
mechanism 1791 is mounted on the distal extremity 1784 and is of
the type hereinbefore described in connection with the embodiments
shown in FIGS. 31 and 32. A sleeve 1796 similar to the sleeve 1771
of the previous embodiment is provided in the present embodiment
for encasing the self-expanding seal mechanism 1791 and for
releasing the same after it has been disposed in an appropriate
position within a vessel adjacent the occlusion to be treated.
Thus, a sleeve 1796 is provided having proximal and distal
extremities 1797 and 1798 and having a bore 1799 extending from the
proximal extremity to the distal extremity which is sized so that
it can receive the guide catheter 1782. It is provided with a
collar 1801 on its proximal extremity which is adapted to be
disposed outside the patient and which is adapted to be grasped by
the physician for pulling the sleeve 1796 proximally to uncover the
self-expanding seal 1791 after the apparatus has been deployed to
permit the self-expansion of the sealing mechanism 1791 to form a
seal with the vessel wall as shown in FIG. 34.
[0247] In accordance with the hereinbefore described descriptions,
it is apparent that the apparatus can be readily deployed and serve
the same function as the main catheter. To accomplish this, the
assembly 1781 can be introduced into the femoral artery and the
distal extremity advanced into the desired location in the arterial
vessel. After it has been properly positioned, the physician can
retract the sleeve 1796 to permit the self-expanding seal mechanism
1791 to expand and to form a seal with the wall of the arterial
vessel to occlude the arterial vessel and interrupt the flow of
blood in the vessel to provide a working space distal of the
occlusion formed. This prevents small particles which may
thereafter be dislodged from moving downstream. Since a central
lumen is available, the therapeutic procedures hereinbefore
described can be employed with the catheter apparatus shown in
FIGS. 31-34.
[0248] Although the self-expanding sealing mechanism 1666 (1791)
can be deployed by retracting the sleeve 1771 (1796) as previously
described, the sealing mechanism can also be deployed by pushing
the flexible elongate member 1652 (guiding catheter 1782) through
the sleeve so that the sealing mechanism can expand. This may be
the preferred way of deploying the sealing mechanism 1666 (1791),
if there is little clearance between the apparatus 1651 (1781) and
the vessel within which the apparatus resides, to reduce the risk
of damaging the patient's vessel. As discussed below in connection
with subsequent figures, the sealing mechanism 1666 (1791) may
alternatively comprise members such as a coil, a ribbon-like
structure, a slotted tube, or a filter-like mesh. In each case, the
sealing mechanism expands to partially or completely occlude the
vessel in question, or alternatively, to anchor an intravascular
device to the vessel.
[0249] Furthermore, although the embodiments described in FIGS.
31-34 are illustrated with an adaptor 1656 or attachment 1786,
these may be easily removed to allow an exchange of catheters over
the member 1652 or 1782. Such an embodiment is shown in FIG. 35.
When retracting the sleeve 1796 to deploy the sealing mechanism
1791, the sleeve 1796 may remain on the member 1782, or may be
completely removed as shown in FIG. 36. By removing the sleeve
completely, the catheters exchanged over the guiding member can
have a lower profile to allow insertion into smaller vessels.
[0250] B. Alternative Self-Expanding Members
[0251] Another embodiment using a braided structure is shown
schematically in FIG. 37, in which a flexible elongate member 1020
is disposed within a second elongate member 1024 such as a
hypotube. A self expanding mechanism 1028 such as a braided
structure is secured to the distal end of the elongate member 1020,
preferably within an indentation 1032 of member 1020. The braided
structure 1028 is only partially encapsulated by a preferably
elastomeric membrane 1036 that makes a seal with the patient's
vessel 1040. (Alternatively, a coating such as a polymeric coating
may be used in place of the membranes disclosed herein.) In this
and the other embodiments, adhesive may be used to secure the
self-expanding mechanism 1028 and the membrane 1036 to the elongate
member 1020. In the embodiment of FIG. 37, the braided structure
1028 and membrane 1036 are designed to be asymmetrical, with more
material being concentrated at the proximal side of the structure
1028. The braids of the embodiments disclosed herein may be
stainless steel 304 or 400, superelastic or heat activated Nitinol,
an iron base shape memory alloy, or a polymer base, such as
polyethylene or polypropylene. They may be constructed, for
example, by using standard equipment such as a braider.
[0252] Although the embodiment of FIG. 37 shows the flexible
elongate member 1020 connected to a guidewire tip 1044, other
technologies for guiding the device through the patient's vessel
1040 may be used in this and the other embodiments, such as a
guidewire (either over the wire or single operator) or the exchange
catheter method, as is well known in the art. Also, although not
explicitly shown in the embodiment of FIG. 37 and the other
embodiments herein, these embodiments may include lumens,
aspiration and irrigation fittings, and collars like those
illustrated in FIGS. 31-34.
[0253] The membrane 1036 is preferably impervious to the flow of
blood (FIG. 38A) for those applications not requiring perfusion,
although a perforated membrane 1036' (FIG. 38B) having numerous
holes 1037 therein may be used in other applications to allow the
passage of blood. The holes 1037 are preferably greater than 10
microns in diameter and may be up to 80 microns or more in diameter
to permit the passage of blood cells (nominally 6-10 microns in
diameter) through the membrane 1036' while blocking larger
particulates such as emboli. Likewise, a perforated membrane 1036'
may be used in the other embodiments disclosed herein.
Antithrombogenic coatings can be used (e.g., heparin) to prevent
thrombosis formation.
[0254] FIG. 39 shows an embodiment in which a braided structure
1050 is not enclosed by a membrane. When the braided structure 1050
comprises, for example, a diamond mesh pattern in which adjacent
wires are separated by about 10-80 microns, the braided structure
permits the passage of red blood cells, while blocking the flow of
matter that may be undesirable, e.g., emboli or other particulates
that may be formed or dislodged during medical procedures. Thus,
this embodiment is well suited for applications for which perfusion
is required.
[0255] Alternative self-expanding media are shown in FIGS. 40 and
41. In FIGS. 40 and 41, a self-expanding filter-like mesh 1060 and
a self-expanding slotted tube 1072, respectively, are surrounded by
a membrane 1062 that is preferably elastomeric. The filter-like
mesh 1060 (or slotted tube 1072) and membrane 1062 are bonded or
otherwise secured to a flexible elongate member 1064, e.g., to an
indentation therein. As with the other self-expanding media
disclosed herein, the filter-like mesh 1060 (or slotted tube 1072)
expands from its unexpanded state when the flexible elongate member
1064 is pushed through a second elongate member 1066, or
alternatively, when the second elongate member 1066 is retracted
over the first elongate member 1064. The filter-like mesh 1060 (or
slotted tube 1072) then expands so that the membrane 1062 forms a
seal with the surrounding vessel 1068. A guidewire tip 1070 aids in
guiding the device through the vessel 1068. The filter-like mesh
1060 and slotted tube 1072 are of a suitable shape memory material
such as Nitinol or (304 or 400) stainless steel. The filter-like
mesh 1060 is fibrous in nature, being somewhat analogous to steel
wool. The slotted tube 1072 has a lattice-like appearance. The
slotted tube 1072 may be constructed, for example, by irradiating a
thin-walled tube with a laser beam to form holes in the tube in the
shape of polygons such as oblong quadrilaterals. An unexpanded,
slotted tube 1074 is shown in FIG. 42.
[0256] FIG. 43 illustrates another embodiment, in which a coil 1080
serves as the self-expanding mechanism. The coil 1080 may be
integrally formed with a first elongate member 1082 or be otherwise
specially joined to it, e.g., by welding or brazing the coil to the
elongate member 1082. The coil 1080 is surrounded by a membrane
1084 that expands with the coil when it is pushed out of a second
elongate member 1086, or alternatively, when the second elongate
member 1086 is retracted from the coil 1080. Thus, the membrane
forms a seal with the surrounding vessel 1090. The membrane 1084
may be attached directly to the first elongate member 1082, or to a
member 1088 such as a disk that is in turn secured to the coil 1080
or the first elongate member 1082. A guidewire tip 1092 for guiding
the device through the vessel 1090 may be attached to the first
elongate member 1082 or to the member 1088, if one is used.
[0257] An embodiment similar to that shown in FIG. 43 is
illustrated in FIG. 44, in which the membrane 1084 is secured at
the proximal end to a separate sheath 1094. In this case, the
sheath 1094 and the first elongate member 1082 are extended
together over and through, respectively, the second elongate member
1086. Assembly may require preloading the coil 1080 through the
distal end of the second elongate member 1086.
[0258] Another embodiment that employs a self-expanding medium is
shown in FIG. 45, in which a plurality of ribbons 1100 make contact
with a membrane 1102 while they expand to urge the membrane towards
the wall of the vessel 1104 where it makes a seal. The ribbons 1100
of this embodiment are preferably secured to a first elongate
member 1106 at both ends of the ribbons, by, for example, gluing
them in place. The ribbons may be
0.001-0.004".times.0.005-0.020".times.0.25-1.0" strips of Nitinol,
stainless steel, or Elgiloy.TM. which expand when urged out of the
second elongate member 1108. A guidewire tip 1110 may be used for
guiding the device through the vessel and is preferably secured to
the distal end of the first elongate member 1106.
[0259] FIG. 46 illustrates an embodiment similar to the one in FIG.
45, in which ribs 1120 such as wires form a series of semicircular
arcs when they expand. The ribs 1120 are surrounded by a membrane
1122 that expands with the ribs to form a seal with the vessel
1124. The number of ribs 1120 is preferably at least three. The
ribs 1120 are preferably attached directly to a first elongate
member 1124 that is surrounded by a second elongate member 1126.
The ribs 1120 themselves are preferably made of a shape memory
material such as Nitinol or stainless steel. A guidewire tip 1128
aids in guiding the device through the vessel 1130.
[0260] As in the other self-expanding embodiments, the
self-expanding mechanism 1100 (1120) is in an unexpanded state when
enclosed by the second elongate member 1108 (1126), and expands
when pushed or pulled beyond the second elongate member 1108
(1126).
[0261] C. Non-Self-Expanding Embodiments
[0262] 1. Heat Activated Embodiments
[0263] FIGS. 44A and 44B illustrate how electrical means can be
used to generate heat to expand an expansion member. A first
elongate member 1082' (and a coil 1080' which adjoins it, coil
1080' and member 1082' being similar to their unprimed
counterparts) is preferably made of heat activated Nitinol, an iron
base shape memory alloy, or another material that expands when
exposed to heat. As shown in FIG. 44A, low profile, low resistivity
electrical lines 1081 and 1083 preferably pass either through or
along the second elongate member 86 and are attached (e.g.,
soldered) to the first elongate member 1082' on either side of the
coil 1080'. When current is applied through the electrical lines
1081 and 1083 (the power supply is not shown but is preferably
outside the patient), the coil 1080' heats up through resistive
heating, and the coil expands to urge the membrane 1084 to contact
the vessel wall 1090. Alternatively, as shown in FIG. 44B, the
first elongate member 1082' may have a coating 1085 of gold or
silver. In this embodiment, the coated elongate member 1082' is
used to pass current (with most of the current preferably being
carried by the coating 1085, so that most of the energy is
deposited, in the coil 1080'), with the circuit being completed
with a low resistivity wire 1087 that is preferably connected
(e.g., soldered) to either the second elongate member 1086 or the
sheath 1094. This principle of resistive heating to expand a
expansion member can be applied to the other embodiments disclosed
herein as well.
[0264] FIGS. 45A, 45B and 45C illustrate how heat transfer using a
liquid can deploy an expansion member. The ribbons 1100' are
preferably made of heat activated Nitinol, an iron base shape
memory alloy, or another material that expands when exposed to
heat. In the embodiment of FIG. 45A, a warm saline solution 1107 is
passed between the first and second elongate members 1106 and 1108
and then over the membrane 1102, so that heat is transferred to the
ribbons 1100'. As the ribbons 1100' heat up, they expand, thereby
urging the membrane 1102 against the vessel wall 1104. As
illustrated in FIG. 45B, the warm saline solution 1107 may also be
passed through the first elongate member 1106 and then through
holes 1109 in member 1106 so that the saline solution 1107 more
directly transfers heat to the ribbons 1100'. In this embodiment,
one or more holes 1111 in the membrane 1102 (distal to where the
seal with the vessel wall 1104 is made) may be used to allow the
saline solution 1107 to flow away beyond the ribbons 1100' after
heat transfer to the ribbons occurs. As illustrated in FIG. 45C,
the saline solution 1107 may also be passed through one or more
closed loop coils or lumens 1113 within the first elongate member
1106. In this way, the ribbons 1100' and the patient's blood are
not exposed directly to any solution. Using heat transfer can also
be applied to the other embodiments disclosed herein, provided the
expansion member is suitably constructed.
[0265] 2. Mechanically Deployed Embodiments
[0266] Other non-self-expanding sealing mechanisms that can be used
for occluding a vessel are described below. In the embodiment of
FIGS. 47-49, a first elongate member 1140, preferably a pull wire,
is (when the device is completely assembled) attached to a brace
member 1144 that is in turn attached to a first ring member 1148.
Adjoining the first ring member 1148 and a second ring member 1152
are a plurality of ribbons 1156 that extend, between the two ring
members. Surrounding the ribbons 1156 is a membrane 1160 that forms
a seal with the patient's vessel 1162 when the ribbons are
expanded. The membrane 1160 is joined to at least one and
preferably both of the ring members' 1148 and 1152. The membrane
1160 can be joined to only one of the ring members 1148 and 1152,
for example, when the membrane 1160 extends far enough in the
longitudinal direction to permit the membrane to make a good seal
with the vessel 1162 when the ribbons 1156 are deployed.
[0267] To assemble the device, the first and second ring members
1148 and 1152, the ribbons 1156, and the membrane 1160 are placed
as a unit around a second elongate member 1166, which has a pair of
oppositely facing holes 1170 and 1172. The brace member 1144 is
inserted through the holes 1170 and 1172 and secured to both the
pull wire 1140 and the first ring member 1148. Further, the second
ring member 1152 is secured to the second elongate member 1166.
This Assembled configuration, with the ribbons 1156 in their
longitudinal orientation, is illustrated in FIG. 48. As illustrated
in FIG. 49, when the pull wire 1140 is retracted, the ribbons 1156
(shown in phantom) and the membrane 1160 that surrounds them are
urged towards the vessel 1162, where the membrane makes a seal with
the vessel. The ribbons 1160 are preferably resilient enough so
that they return to their longitudinal orientation when the pull
wire 1140 is released. The elasticity and resilience of the pull
wire 1140 also helps the ribbons 1156 return to their undeployed
configuration. A guidewire tip 1171 may be used to assist in
guiding the device to the desired location in the vessel 1162.
[0268] A preferred way of retracting the pull wire 1140 is shown in
FIGS. 50A and 50B. FIG. 50A shows the pull wire 1140, which is
attached to the brace member 1144. A rotatable handle 1180 is
attached to a locking member 1184 which in turn is fastened to the
pull wire 1140. When the locking member 1184 clears the second
elongate member 1166 within which it resides (which is preferably
outside the patient), the locking member and rotatable handle 1180
may be oriented as illustrated in FIG. 50B to keep the pull wire
1140 taught, thereby preventing the sealing mechanism from
returning to its undeployed position. The pull wire 1140 may be
made of stainless or nitinol and may have a diameter of 0.006-0.008
inches, for a catheter having an O.D. of 0.014", for example.
[0269] An alternative to the deployment apparatus illustrated in
FIGS. 50A and 50B is shown in FIG. 51A, in which a handle member
1190 is grasped by the clinician to retract the pull wire 1140,
thereby deploying the sealing mechanism. Once extended, the sealing
mechanism preferably has the tendency to return to its undeployed
position, which in the process pulls the pull wire 1140 back into
the second elongate member 1166. This can be prevented by inserting
a spacer member 1194 between the handle member 190 and the second
elongate member 1166. After the medical procedure is complete, and
occlusion of the vessel is no longer required, the spacer member
1194 can be removed and the pull wire 1140 and the sealing
mechanism returned to their respective undeployed positions. The
device can then be removed from the patient.
[0270] Both pull wire mechanisms shown in FIGS. 50A and 51A are
preferably engaged by use of an adaptor 1186 or 1196, as shown in
FIGS. 50C and 51B, respectively. This adaptor 1186 or 1196 allows
for easier control of the pull wire mechanism. In FIG. 50C, the
knob 1188 is adapted to connect to the rotatable handle 1180 and
locking member 1184. By turning and pulling the knob 1188, the pull
wire 1140 may be retracted to deploy the sealing mechanism. In FIG.
51B, the handle 1198 can be grasped to pull handle member 1190 away
from second elongate member 1166. This opens up a space between
members 1190 and 1166 to allow spacer member 1194 to be inserted
through a window in adaptor 1196 for holding the pull wire 1140
taut. Once the pull wire mechanism is engaged, the adaptor in both
embodiments may be removed to allow for an exchange over the
proximal end of the pull wire devices.
[0271] Although the principle of using a non-self-expanding
mechanism has been illustrated in FIGS. 47-49 with respect to
deformable ribbons, other non-self-expanding mechanisms, as
illustrated in FIGS. 52A-52D, can be employed in conjunction with
the brace member 1144 and the first and second ring members 1148
and 1152. For example, instead of using ribbons 1156, a
non-self-expanding braided structure 1200 can be used, in which the
braided structure 1200 adjoins first and second ring members 1148
and 1152 and is covered with a membrane 1160 to form the unit 1204
shown in FIG. 52A. The unit 1204 can be used in conjunction with an
elongate member 1166, a brace member 1144, a guidewire tip 1171, a
first elongate member 1140 such as a pull wire, a rotatable handle
1180, and a locking member 1184 to form a device analogous to the
ribbon-based device of FIG. 47. Alternatively, other mechanisms can
be used for securing the pull wire 1140, such as a handle member
1190 and a spacer member 1194.
[0272] Other non-self-expanding mechanisms such as a filter-like
mesh 1208, a slotted tube 1212, and coils 1216 can be used to form
units 1220, 1230, and 1240 analogous to the braided structure unit
1204 as shown in FIGS. 52B, 52C and 52D. Units 1220, 1230, and 1240
can likewise be used to construct devices analogous to the
ribbon-based device illustrated in FIGS. 47-51. Further, if unit
1204 is used without a membrane, it may assist in blood perfusion
if the braided structure 1200 is suitably constructed.
Alternatively, perforated membranes like membranes 1036' of FIG.
38B may be used to permit blood perfusion. Although the ribbons
1156, the braided structure 1200, the filter-like mesh 1208, the
slotted tube 1212, and the coils 1216 must be actively deployed
(e.g. with a pull wire 1140), they are nevertheless similar to
their self-expanding counterparts.
[0273] It should be understood that the scope of the present
invention is not be limited by the illustrations or the foregoing
description thereof, but rather by the appended claims, and certain
variations and modifications of this invention will suggest
themselves to one of ordinary skill in the art.
* * * * *