U.S. patent application number 11/877515 was filed with the patent office on 2008-02-14 for balloon ctheter having external guidewire.
This patent application is currently assigned to ADVANCED CARDIOVASCULAR SYSTEMS, INC.. Invention is credited to Jeong S. Lee, Christopher McMurtry, Kenneth L. Wantink.
Application Number | 20080039787 11/877515 |
Document ID | / |
Family ID | 32593998 |
Filed Date | 2008-02-14 |
United States Patent
Application |
20080039787 |
Kind Code |
A1 |
McMurtry; Christopher ; et
al. |
February 14, 2008 |
BALLOON CTHETER HAVING EXTERNAL GUIDEWIRE
Abstract
A catheter having an elongated shaft with an inflation lumen and
a guidewire lumen, a balloon on a distal shaft section, and a
proximal intermediate port proximal to the balloon and a distal
intermediate port distal to the balloon, the intermediate ports
being in communication with the guidewire lumen and being
configured to slidably receive a guidewire therethrough so that the
guidewire extends into or out of a proximal section of the
guidewire lumen through the proximal intermediate port, extends
along an outer surface of the balloon, and extends into or out of a
distal section of the guidewire lumen through the distal
intermediate port. The balloon is inflated in a patient's blood
vessel to perform a medical procedure, with the section of the
guidewire extending along an outer surface of the balloon providing
improved balloon retention at the desired location in the blood
vessel during inflation of the balloon.
Inventors: |
McMurtry; Christopher;
(Murrieta, CA) ; Lee; Jeong S.; (Diamond Bar,
CA) ; Wantink; Kenneth L.; (Temecula, CA) |
Correspondence
Address: |
FULWIDER PATTON, LLP (ABBOTT)
6060 CENTER DRIVE
10TH FLOOR
LOS ANGELES
CA
90045
US
|
Assignee: |
ADVANCED CARDIOVASCULAR SYSTEMS,
INC.
3200 Lakeside Drive
Santa Clara
CA
95054-2807
|
Family ID: |
32593998 |
Appl. No.: |
11/877515 |
Filed: |
October 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10326359 |
Dec 20, 2002 |
7300415 |
|
|
11877515 |
Oct 23, 2007 |
|
|
|
Current U.S.
Class: |
604/103.03 |
Current CPC
Class: |
A61M 2025/0037 20130101;
A61M 2025/0039 20130101; A61M 25/0029 20130101; A61M 2025/0004
20130101; A61M 25/003 20130101; A61M 25/104 20130101; A61M
2025/1056 20130101; A61M 2025/0034 20130101 |
Class at
Publication: |
604/103.03 |
International
Class: |
A61M 25/10 20060101
A61M025/10 |
Claims
1-23. (canceled)
24. A method of performing a medical procedure in a patient's body
lumen, comprising: a) advancing a balloon catheter within a
patient's body lumen to a desired position of a stenosed section of
the body lumen, the balloon catheter having an elongated shaft with
an inflation lumen, and a guidewire lumen in communication with a
guidewire proximal port and a guidewire distal port, and having a
balloon on a distal shaft section, with a proximal end, a distal
end, and an interior in fluid communication with the inflation
lumen, and having a proximal intermediate port proximal to the
balloon and distal to the guidewire proximal port, and a distal
intermediate port distal to the balloon and proximal to the
guidewire distal port, the intermediate ports being in
communication with the guidewire lumen and being configured to
slidably receive a guidewire therethrough, with a guidewire in the
guidewire lumen proximal and distal to the balloon, the guidewire
extending through the proximal and distal intermediate ports so
that a section of the guidewire extends along an outer surface of
the balloon; and b) positioning the balloon so that a working
length of the balloon extends along the stenosed section of the
body lumen, and inflating the balloon so that the section of the
guidewire along the outer surface of the balloon contacts the
stenosed section of a wall defining the body lumen during inflation
of the balloon.
25. The method of claim 24 wherein the balloon dilates the stenosed
section of the body lumen during b), with the section of the
guidewire along the outer surface of the balloon in contact with
the body lumen frictionally engaging the body lumen wall.
26. The method of claim 24 wherein the balloon inflates into
contact with the body lumen wall with an insubstantial amount of
longitudinal slippage proximally or distally from the desired
position in the body lumen.
27. The method of claim 24 wherein a portion of the tubular shaft
and a support member extend in the balloon interior, and b)
comprises inflating the balloon without substantial bowing of the
balloon.
28. The method of claim 24 wherein the balloon outer surface has an
exposed section in a noninflated configuration prior to being
inflated to an inflated configuration, and the section of the
guidewire extending along the outer surface of the balloon extends
along the outer surface exposed section of the balloon in the
noninflated configuration, and inflating the balloon comprises
directing inflation fluid into the balloon interior.
29. The method of claim 24 wherein the balloon has a noninflated
folded configuration prior to being inflated to an inflated
configuration, the outer surface of the balloon having an exposed
first section and an unexposed second section in the folded
configuration, and the inflated configuration exposes both the
first and second sections of the balloon outer surface, and the
section of the guidewire extending along the outer surface of the
balloon extends at least in part along the outer surface unexposed
section of the balloon in the folded configuration, and inflating
the balloon exposes the section of the guidewire extending along
the outer surface of the balloon as the balloon unfolds.
Description
BACKGROUND OF THE INVENTION
[0001] This invention generally relates to catheters, and
particularly intravascular catheters for use in percutaneous
transluminal coronary angioplasty (PTCA) or for the delivery of
stents.
[0002] In percutaneous transluminal coronary angioplasty (PTCA)
procedures a guiding catheter is advanced in the patient's
vasculature until the distal tip of the guiding catheter is seated
in the ostium of a desired coronary artery. A guidewire is first
advanced out of the distal end of the guiding catheter into the
patient's coronary artery until the distal end of the guidewire
crosses a lesion to be dilated. A dilatation catheter, having an
inflatable balloon on the distal portion thereof, is advanced into
the patient's coronary anatomy over the previously introduced
guidewire until the balloon of the dilatation catheter is properly
positioned across the lesion. Once properly positioned, the
dilatation balloon is inflated with inflation fluid one or more
times to a predetermined size at relatively high pressures so that
the stenosis is compressed against the arterial wall and the wall
expanded to open up the vascular passageway. Generally, the
inflated diameter of the balloon is approximately the same diameter
as the native diameter of the body lumen being dilated so as to
complete the dilatation but not over expand the artery wall. After
the balloon is finally deflated, blood resumes through the dilated
artery and the dilatation catheter and the guidewire can be removed
therefrom.
[0003] In such angioplasty procedures, there may be restenosis of
the artery, i.e. reformation of the arterial blockage, which
necessitates either another angioplasty procedure, or some other
method of repairing or strengthening the dilated area. To reduce
the restenosis rate of angioplasty alone and to strengthen the
dilated area, physicians now normally implant an intravascular
prosthesis, generally called a stent, inside the artery at the site
of the lesion. Stents may also be used to repair vessels having an
intimal flap or dissection or to generally strengthen a weakened
section of a vessel or to maintain its patency. Stents are usually
delivered to a desired location within a coronary artery in a
contracted condition on a balloon of a catheter which is similar in
many respects to a balloon angioplasty catheter, and expanded
within the patient's artery to a larger diameter by expansion of
the balloon. The balloon is deflated to remove the catheter and the
stent left in place within the artery at the site of the dilated
lesion. See for example, U.S. Pat. No. 5,507,768 (Lau, et al.) and
U.S. Pat. No. 5,458,615 (Klemm, et al.), which are incorporated
herein by reference.
[0004] An essential step in effectively performing a PTCA procedure
is properly positioning the balloon catheter at a desired location
within the coronary artery. To properly position the balloon at the
stenosed region, the catheter must have good pushability (i.e.,
ability to transmit force along the length of the catheter) and
flexibility to be readily advanceable within the tortuous anatomy
of the patient's vasculature. Conventional balloon catheters for
intravascular procedures, such as angioplasty and stent delivery,
frequently have relatively a stiff proximal shaft section to
facilitate advancement of the catheter within the patient's body
lumen and a relatively flexible distal shaft section to facilitate
passage through tortuous anatomy such as distal coronary and
neurological arteries without damage to the luminal wall. To
facilitate advancement of the catheter within the tortuous
vasculature, conventional balloon catheters for angioplasty and
stent delivery frequently have a lubricious coating on at least a
portion of an outer surface of the catheter. However, one
difficulty has been the tendency of the balloon having a lubricious
coating thereon to slip out of position during inflation of the
balloon. Accordingly, it would be a significant advance to provide
a catheter balloon having improved balloon retention, and without
inhibiting movement of the catheter within the vasculature.
SUMMARY OF THE INVENTION
[0005] The invention is directed to a catheter having an elongated
shaft with an inflation lumen and a guidewire lumen, a balloon on a
distal shaft section, a guidewire proximal port, a guidewire distal
port, a proximal intermediate port proximal to the balloon, and a
distal intermediate port distal to the balloon. The intermediate
ports are intermediate to (i.e., between) the guidewire proximal
and distal ports and in communication with the guidewire lumen, and
are configured to slidably receive a guidewire therethrough so that
the guidewire extends into or out of a proximal section of the
guidewire lumen through the proximal intermediate port, extends
along an outer surface of the balloon, and extends into or out of a
distal section of the guidewire lumen through the distal
intermediate port. The balloon is inflated in a patient's blood
vessel to perform a medical procedure, with the section of the
guidewire extending along an outer surface of the balloon providing
improved balloon retention at the desired location in the blood
vessel during inflation of the balloon.
[0006] The balloon catheter of the invention may comprise a variety
of suitable balloon catheters, including coronary and peripheral
dilatation catheters, stent delivery catheters, drug delivery
catheters, and the like. A balloon catheter of the invention
generally comprises an elongated shaft with an inflation lumen and
a guidewire lumen, and an inflatable balloon on the distal shaft
section having an interior in fluid communication with the
inflation lumen. The guidewire lumen has a guidewire proximal port
and the proximal intermediate port located proximal to the balloon,
and a guidewire distal port and the distal intermediate port
located distal to the balloon. The proximal intermediate port is
located distal to the guidewire proximal port, and the distal
intermediate port is located proximal to the guidewire distal port.
The guidewire lumen extends at least between the guidewire proximal
port and the proximal intermediate port, and at least between the
guidewire distal port and the distal intermediate port. Thus, the
guidewire extends along an outer surface of the balloon but
proximal and distal to the balloon it is within sections of the
guidewire lumen located between the intermediate ports and the
guidewire ports. As a result, the tendency of a guidewire external
to the catheter shaft to become wrapped or tangled with the
catheter shaft during torquing of the catheter within the patient's
body lumen is prevented or inhibited.
[0007] In one embodiment, the catheter is a rapid exchange type
catheter having the guidewire proximal port located distal to the
proximal end of the shaft, and preferably in the distal shaft
section spaced a relatively short distance proximally from the
guidewire distal port and a relatively long distance distally from
the proximal end of the catheter shaft, with a relatively short
guidewire receiving lumen extending in the distal shaft section. In
an alternative embodiment, the catheter is an over-the-wire type
catheter having the guidewire proximal port at the proximal end of
the catheter.
[0008] In one embodiment, the tubular shaft has a portion which
extends in the balloon interior. The shaft portion in the balloon
interior preferably provides support for the balloon, to preferably
prevent or inhibit the balloon from bowing during inflation of the
balloon or from or axially bunching during advancement in the
patient's body lumen. The tubular shaft portion extending through
the balloon interior defines a lumen which typically is an
extension of the guidewire lumen. However, in a presently preferred
embodiment, the lumen of the shaft portion extending through the
balloon interior is not in fluid communication with the portion of
the guidewire lumen located proximal to the proximal intermediate
port and/or with the portion of the guidewire lumen located distal
to the distal intermediate port. Specifically, in one embodiment, a
support member is in the shaft lumen extending along at least part
of the length between the proximal and distal intermediate ports,
so that the support member occludes the lumen. In a presently
preferred embodiment, the support member has a length which extends
from the proximal intermediate port to the distal intermediate
port, so that the support member is in the lumen of the shaft
portion extending through the balloon interior to preferably
provide additional support at the balloon. The support member is
typically a metallic and/or polymeric mandrel (e.g., rod or plug),
and in one embodiment the ends of the support member are configured
to provide a surface which guides the guidewire out of the
guidewire lumen and along the outer surface of the balloon. The
shaft portion is typically shrunk down onto the support member, so
that the support member fully occludes the lumen therein. In
alternative embodiments, the support member only partially occludes
the lumen, with a space remaining between the support member and
the inner surface of the shaft, although the space is typically
sufficiently small that the support member nonetheless prevents the
guidewire from extending in the part of the shaft lumen having the
support member therein. In an alternative embodiment, the tubular
shaft does not extend through the balloon interior from the
proximal to the distal end of the balloon. However, in the
embodiment in which the tubular shaft does not extend through the
balloon interior, a support member such as a mandrel or rod is
typically provided which extends through the balloon interior.
[0009] In one embodiment, the elongated shaft comprises an outer
tubular member defining the inflation lumen, and an inner tubular
member defining the guidewire lumen and extending within the outer
tubular member lumen and distally therebeyond through the balloon
interior. However, a variety of suitable shaft configurations may
be used as are conventionally known, including a dual lumen type
shaft having a first lumen forming the guidewire lumen and a second
lumen forming the inflation lumen in side-by-side relation thereto.
In the dual lumen type shaft design, the shaft portion extending
through the balloon interior may be formed by a tubular extension
extending distally from the distal end of the dual-lumen polymeric
tube, or alternatively, a support member such as a mandrel or rod
may extend alone from the distal end of the dual-lumen polymeric
tube and without a tubular shaft section therearound.
[0010] A method of performing a medical procedure using a balloon
catheter embodying features of the invention generally comprises
positioning the balloon so that the balloon working length extends
along the stenosed section of the blood vessel, and inflating the
balloon. In a presently preferred embodiment, the medical procedure
is dilating a stenosis, so that the balloon dilates the stenosed
section of the blood vessel, with the section of the guidewire
along the outer surface of the balloon contacting the stenosed
section of the blood vessel wall during inflation of the balloon to
preferably frictionally engage the blood vessel wall. The guidewire
thus facilitates dilating the stenosis, by enhancing the ability of
the inflated balloon to remain in position in contact with the
stenosed section of the blood vessel wall, with an insubstantial
amount of longitudinal slippage proximally or distally from the
desired position in the blood vessel. In one embodiment, the
guidewire has a rounded outer surface which prevents or inhibits
damage to the blood vessel wall as the balloon presses the
guidewire against the blood vessel wall.
[0011] In one embodiment, the section of the guidewire extending
along the outer surface of the balloon is on an exposed section of
the outer surface of the noninflated balloon. The deflated balloon
typically forms wings which are wrapped around the outside of the
balloon, or otherwise forms a folded configuration, providing a low
profile configuration for introduction and advancement of the
catheter within the patient's body lumen prior to inflation of the
balloon in the body lumen. In the folded configuration, the outer
surface of the balloon has an exposed first section and an
unexposed second section, and the inflated configuration exposes
both the first and second sections of the balloon outer surface. In
one embodiment, the section of the guidewire extending along the
outer surface of the balloon is located outside the unexposed
channel formed by the folded wings in the folded configuration, and
is thus on an exposed section of the outer surface of the balloon.
In an alternative embodiment, the section of the guidewire
extending along the outer surface of the balloon extends at least
in part within the unexposed channel formed by the fold wings
(i.e., along an unexposed section of the outer surface of the
balloon in the folded configuration). With the guidewire passing
through the channel formed under the wing between the wing and the
underlying section of the outer surface of the balloon in the
folded configuration, the guidewire tends to be guided or directed
into the proximal intermediate port during insertion of the
catheter over the guidewire.
[0012] The balloon catheter has improved balloon retention during
inflation of the balloon in the patient's body lumen, due to the
catheter configuration having a section of the guidewire extending
along the outer surface of the balloon. The portion of the
guidewire extending along the outer surface of the inflated balloon
preferably frictionally engages the wall of the body lumen,
preferably without damaging the body lumen wall. Moreover, the
shaft configuration provides improved support at the balloon for
enhanced catheter performance. These and other advantages of the
invention will become more apparent from the following detailed
description of the invention and the accompanying exemplary
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an elevational view, partially in section, of a
rapid exchange type balloon catheter which embodies features of the
invention.
[0014] FIGS. 2-4 are transverse cross sectional views of the
catheter shown in FIG. 1, taken along lines 2-2, 3-3, and 4-4,
respectively.
[0015] FIG. 5 illustrates the balloon catheter of FIG. 1, with the
balloon fully inflated in a patient's body lumen.
[0016] FIG. 6 is an elevational view, partially in section, of an
alternative embodiment of an over-the-wire type balloon catheter
which embodies features of the invention.
[0017] FIG. 7 is an enlarged elevational view of a distal section
of an alternative embodiment, having the guidewire underneath a
wing of a folded balloon.
[0018] FIG. 8 is a transverse cross sectional view of the catheter
of FIG. 7 taken along line 8-8.
[0019] FIG. 9 is a transverse cross sectional view of an
alternative embodiment having a dual lumen extruded shaft.
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 1 illustrates a rapid exchange type balloon catheter
10, generally comprising a shaft 11 with an inflation lumen 12, a
guidewire lumen 13 in a distal shaft section configured to
slidingly receive a guidewire 15, and a balloon 14 on the distal
shaft section. An adapter 16 at the proximal end of catheter shaft
11 is configured to direct inflation fluid into inflation lumen 12.
FIG. 1 illustrates the balloon 14 prior to complete inflation
within the patient's body lumen 27. In use, the distal end of
catheter 10 is advanced to a desired region of the patient's body
lumen 27 in a conventional manner either over a previously
positioned guidewire, or with guidewire 15 already in the catheter
10. The balloon 14 is inflated to perform a procedure, which in a
preferred embodiment comprises dilating a stenosed region of the
body lumen, or a previously stented body lumen that is restenosed
(commonly referred to as in-stent-restenosis), and the balloon
deflated for repositioning or removing the catheter 10 from the
body lumen. However, the balloon catheter may be suitable for a
variety of intraluminal procedures, such as expanding a stent (not
shown) mounted on the balloon.
[0021] In the embodiment of FIG. 1, a distal section of the shaft
11 comprises an outer tubular member 17 defining the inflation
lumen 12, and an inner tubular member 18 defining the guidewire
lumen 13 extending from a guidewire distal port 19 in the distal
end of the catheter shaft to a guidewire proximal port 20 spaced
distally from the proximal end of the catheter shaft. A proximal
shaft section comprises a tubular member, which in the embodiment
of FIG. 1 is a metallic tubular member 24 having a polymeric jacket
25 on an outer surface thereof, defining a proximal section of the
inflation lumen 12. Inflatable balloon 14 has an elongated
cylindrical expandable working section, a proximal skirt section
sealingly secured to the distal end of outer tubular member 17 and
a distal skirt section sealingly secured to the distal end of inner
tubular member 18, so that its interior is in fluid communication
with inflation lumen 12. The tubular shaft 11 thus has a portion
extending through the interior of balloon 14. Although the shaft
portion extending through the interior of balloon 14 in the
embodiment of FIG. 1 is an integral extension of the inner tubular
member 18, in alternative embodiments (not shown), a shaft portion
extending through the interior of the balloon 14 is formed by a
separate tubular member secured to the shaft 11 at a location
adjacent to the proximal end of the balloon 14.
[0022] A proximal intermediate port 21 in communication with the
guidewire lumen 13 is located proximal to the balloon 14 and distal
to the guidewire proximal port 20. A distal intermediate port 22 in
communication with the guidewire lumen 13 is located distal to the
balloon 14 and proximal to the guidewire distal port 19. The
proximal and distal intermediate ports 21, 22 extend through a
sidewall of the outer tubular member 17 and a sidewall of the inner
tubular member 18, allowing the guidewire to enter/exit a proximal
section of the guidewire lumen through the proximal intermediate
port 21 and exit/enter a distal section of the guidewire lumen 13
through the distal intermediate port 22. The guidewire 15 thus
extends outside the catheter and along an outer surface of the
balloon 14 between the two intermediate ports 21, 22. FIGS. 2-4
illustrate transverse cross sections of FIG. 1, taken along lines
2-2, 3-3, and 4-4, respectively. Although in the illustrated
embodiment the proximal intermediate port 21 extends through the
sidewall a polymeric tube forming outer tubular member 17, in
alternative embodiments (not shown), the outer tubular member 17
may comprises multiple tubes joined lengthwise, end-to-end, with
the intermediate port 21 formed by the end opening of one of the
tubes.
[0023] The distal intermediate port 22 extends through the sidewall
of both the balloon distal skirt section and the underlying inner
tubular member 18 in the embodiment of FIG. 1, for increased
support at the distal intermediate port 22. However, in alternative
embodiments (not shown), the distal intermediate port 22 may be
located distal to the distal end of the balloon distal skirt
section. In the embodiment of FIG. 1, the proximal intermediate
port 21 is formed by joining a portion of the inner surface of the
outer tubular member 17 to a portion of the outer surface of the
inner tubular member 18. For example, the outer tubular member may
be pressed down onto the inner tubular member and heated, to heat
fuse thereto. The proximal intermediate port 21 is then formed by
drilling through, or otherwise removing material from, the outer
and inner tubular members 17, 18, to form the port 21. The portion
of the outer surface of the inner tubular member 18 fused or
otherwise joined to the outer tubular member 17 at the proximal
intermediate port 21 extends only partially around the
circumference thereof, so that the inflation lumen 12 extending
along the proximal intermediate port 21 is defined by the space
remaining between the outer and inner tubular members 17, 18
therealong. In the embodiment of FIG. 1, the joined portion extends
to the distal end of the outer tubular member 17. Alternatively,
the joined portion may extend a relatively short distance along the
length of the outer tubular member 17, so that the inflation lumen
12 has an annular shape defined by the annular space between the
outer and inner tubular members 17, 18 along at least a section of
the shaft located proximally and distally of the proximal
intermediate port 21.
[0024] In the embodiment of FIG. 1, the proximal and distal
intermediate ports 21, 22 are oriented in the sidewalls to open
outwardly in a direction pointing toward the balloon, and thus are
not formed through the sidewall at a perpendicular angle relative
to the longitudinal axis of the shaft. The proximal intermediate
port 21 is preferably spaced a short distance proximally of the
balloon 14, which facilitates guidewire placement through the port
21. In one embodiment, the proximal intermediate port 21 is spaced
about 1 to about 10 cm from the proximal end of the balloon 14. The
proximal intermediate port is typically closer to the proximal end
of the balloon than to the rapid exchange guidewire port 20, and in
one embodiment is about 20 to about 30 cm distally from the rapid
exchange guidewire proximal port 20, although the absolute distance
from the rapid exchange guidewire proximal port 20 may vary
depending on factors such as the desired use of the balloon
catheter 10. In alternative embodiments (not shown), the proximal
intermediate port 21 may be closer to the balloon proximal end, and
may extend through a longer balloon proximal skirt section. The
distal intermediate port 22 is typically spaced a relatively short
distance distally from the distal end of the inflatable interior
portion of the balloon, and specifically in one embodiment is about
0.2 to about 1 cm distally thereof.
[0025] In the embodiment of FIG. 1, a support member 29 comprising
a solid mandrel (e.g., rod) is located in the portion of the
guidewire lumen 13 extending in the balloon interior. In the
embodiment of FIG. 1, the support member has a wedge shaped
proximal end surface located at (i.e., radially aligned with) the
proximal intermediate port 21, and a wedge shaped distal end
surface located at the distal intermediate port 22. In the
embodiment of FIG. 1, the support member proximal and distal ends
are wedge shaped or truncated to provide a surface facilitating
guiding the guidewire 15 through intermediate ports 21, 22. In the
embodiment of FIG. 1, the support member 29 extends the entire
length between the proximal and distal intermediate ports 21, 22.
However, in alternative embodiments (not shown), one or more
support members are used having lengths less than the distance
between the proximal and distal intermediate ports 21,22. For
example, in one embodiment (not shown), a first support member with
a wedge shaped proximal end is in guidewire lumen 13 at the
proximal intermediate port 21, and a second support member with a
wedge shaped distal end is in the guidewire lumen 13 at the distal
intermediate port 22, without a section of the support member being
in the section of the guidewire lumen located between the first and
second support members. In the embodiment of FIG. 1 the support
member 29 is a solid polymeric mandrel in the guidewire lumen 13.
However, a variety of suitable support members providing support at
the balloon to prevent or inhibit the balloon 14 from bowing during
inflation or from axially bunching may be used, such as coiled or
braided reinforcements (not shown) in the wall of the catheter
shaft 11 extending through the balloon interior, although first and
second support members comprising mandrels having a wedge shaped
end would typically at least be provided at the intermediate ports
21,22 to facilitate guiding the guidewire 15 through intermediate
ports 21, 22, as discussed above. In a presently preferred
embodiment, the polymeric material forming the support member 29 is
the same as the polymeric material forming the inner surface of the
inner tubular member 18 therearound, such as for example high
density polyethylene (HDPE) or a nylon. However, the support member
29 can be formed of a variety of suitable materials including
metallic materials such as a NiTi alloy. The support member 29 is
preferably secured in the guidewire lumen 13, as for example by
heat shrinking the inner tubular member 18 down onto the support
member 29. The support member thus completely or partially occludes
the guidewire lumen 13 such that the passage therethrough of
guidewire 15 is blocked.
[0026] FIG. 1 illustrates the balloon catheter 10 with the balloon
across a stenotic region of the patient's blood vessel 27. The
balloon is inflated by directing inflation fluid through the
inflation lumen 12, to expand the balloon. FIG. 5 illustrates the
balloon catheter of FIG. 1, with the balloon fully inflated, so
that the balloon working length contacts and dilates the stenotic
region. The section of the guidewire 15 extending along the outer
surface of the balloon contacts the stenosed section of the blood
vessel during inflation of the balloon 14. As a result, the section
of the guidewire 15 frictionally engages the blood vessel wall, so
that the balloon 14 has an insubstantial amount of longitudinal
slippage proximally or distally from the desired position in the
blood vessel 27. The balloon 14 is then deflated, and the balloon
catheter 10 can be withdrawn proximally over the guidewire 15
leaving the guidewire in place, or withdrawn with the guidewire
15.
[0027] FIG. 6 illustrates an over-the-wire type balloon catheter 40
embodying features of the invention. Catheter 40 generally
comprises an elongated catheter shaft 41 having an outer tubular
member 42 and an inner tubular member 43. Inner tubular member 43
defines a guidewire lumen 44 configured to slidingly receive a
guidewire 45, with a guidewire proximal port at the proximal end of
the catheter, and a guidewire distal port 48 at the catheter distal
end. The coaxial relationship between outer tubular member 42 and
inner tubular member 43 defines annular inflation lumen 46. An
inflatable balloon 47 disposed on a distal section of catheter
shaft 41 has a proximal skirt section sealingly secured to the
distal end of outer tubular member 42 and a distal skirt section
sealingly secured to the distal end of inner tubular member 43, so
that its interior is in fluid communication with inflation lumen
46. An adapter 49 at the proximal end of catheter shaft 41 is
configured to provide access to guidewire lumen 44, and to direct
inflation fluid through arm 50 into inflation lumen 46.
[0028] A proximal intermediate port 51 in communication with the
guidewire lumen 44 is located proximal to the balloon 47 and distal
to the guidewire proximal port, and a distal intermediate port 52
in communication with the guidewire lumen 44 is located distal to
the balloon 47 and proximal to the guidewire distal port 48. The
proximal and distal intermediate ports 51, 52 extend through a
sidewall of the outer tubular member 42 and a sidewall of the inner
tubular member 43. The discussion above relating to the
intermediate ports 21, 22 of the embodiment of FIG. 1 applies to
the intermediate ports 51, 52 of the over-the-wire catheter 40 of
FIG. 6.
[0029] A support member 53 is in the guidewire lumen 44 between the
proximal and distal intermediate ports 51, 52. Support member 53
comprises a metallic mandrel 54 surrounded by polymeric material
55. The polymeric material 55 forms the wedge-shaped ends of the
support member 53, facilitating directing the guidewire through the
intermediate ports 51, 52 as discussed above in relation to the
embodiment of FIG. 1. The metallic mandrel 54 embedded in the
polymeric material 55 may be formed using a variety of suitable
methods. For example, in one embodiment, a metallic mandrel is
placed in the lumen of a polymeric tube having a length longer than
the metallic mandrel, and the assembly heated, causing the
polymeric material 55 to flow and form the polymeric ends of the
support member 53 at either end of the metallic mandrel 54.
[0030] In the embodiment of FIG. 6, the balloon is illustrated in a
folded configuration, with folded wings 56 for introduction and
advancement within the body lumen 27. In the figures illustrating
the uninflated balloon, the distance between the inner surface of
the balloon interior and the outer surface of the portion of the
catheter shaft extending therethrough is exaggerated in the figures
for ease of illustration. The guidewire 45 extends along an exposed
outer surface of the folded balloon 47. In an alternative
embodiment illustrated in FIG. 7 the guidewire extends underneath a
folded wing 56 of the noninflated balloon 47. As best shown in FIG.
8, illustrating a transverse cross section of the distal section of
the catheter of FIG. 7, taken along line 8-8, the balloon in the
noninflated folded configuration prior to being inflated to an
inflated configuration, has an outer surface with an exposed first
section 57 and an unexposed second section 58 in the folded
configuration. In the inflated configuration the balloon interior
is filled with inflation fluid, so that the inflated configuration
exposes both the first and second sections 57, 58 of the balloon
outer surface, and the guidewire 45 becomes exposed (for contacting
the wall of the body lumen as illustrated in FIG. 5). Thus in the
embodiment of FIG. 7, the section of the guidewire 45 extending
along the outer surface of the balloon extends at least in part
along the outer surface unexposed section 58 of the balloon in the
folded configuration.
[0031] The guidewire 15, 45 is a conventional guidewire, typically
having a rounded outer surface and a coiled distal tip. In a
presently preferred embodiment, the coiled distal tip of the
guidewire typically has a length sufficiently long to extend along
the length of the outer surface of the balloon 14, 47, with the
coiled distal tip providing enhanced frictional contact with the
wall of the patient's blood vessel 27 during inflation of the
balloon 14, 47. Conventional guidewires for angioplasty and
peripheral or neural dilatation procedures typically have an outer
diameter of about 0.3 to about 0.45 mm, and a length of about 190
to about 300 cm, with a coiled distal tip having a length of about
2 to about 25 cm.
[0032] Although in the illustrated embodiments, the catheter shafts
1, 41 comprise inner and outer tubular members defining the
inflation lumen therebetween, in an alternative embodiment, the
shaft may comprise a dual-lumen extruded polymeric tubular member.
FIG. 9 illustrates a transverse cross section of a dual-lumen
extruded polymeric catheter shaft 70, having an inflation lumen 71
and a guidewire lumen 72. Although not illustrated, a support
member such as a mandrel is typically provided in the distal end of
the guidewire lumen 72, to extend distally beyond the distal end of
the dual lumen shaft and through the interior of the balloon,
similar to support member 29, 53 discussed above. Typically a
tubular section of the catheter shaft does not extend beyond the
distal end of the dual lumen shaft 70, so the support member in the
balloon interior is not surrounded by the catheter shaft.
[0033] To the extent not previously discussed herein, the various
catheter components may be formed and joined by conventional
materials and methods. Outer tubular member can be formed by
conventional techniques, such as by extruding and necking materials
found useful in intravascular catheters such a polyethylene,
polyvinyl chloride, polyesters, polyamide, polyimides,
polyurethanes, and composite materials. Although illustrated as
one-piece tubular members, it should be understood that the outer
and inner tubular members 17, 18 may be formed of multiple tubular
members or multilayered tubular members. For example, the outer
tubular member 17 typically comprises multiple tubular members
joined end to end, to provide increasing flexibility distally along
the length of the catheter.
[0034] The length of the balloon catheter 10, 40 is generally about
137 to about 145 centimeters, and typically about 140 centimeters
for PTCA. The outer tubular member 14 distal section has an outer
diameter (OD) of about 0.028 to about 0.036 inch (0.70-0.91 mm),
and an inner diameter (ID) of about 0.024 to about 0.035 inch
(0.60-0.89 mm), and the outer tubular member 14 proximal section
has an OD of about 0.017 to about 0.034 inch (0.43-0.87 mm), and an
inner diameter (ID) of about 0.012 to about 0.022 inch (0.30-0.56
mm). The inner tubular member 16 has an OD of about 0.017 to about
0.026 inch (0.43-0.66 mm), and an ID of about 0.015 to about 0.018
inch (0.38-0.46 mm) depending on the diameter of the guidewire to
be used with the catheter. The balloon 14, 47 is typically about 8
to about 38 mm in length, with an inflated working diameter of
about 1.5 to about 5 mm.
[0035] While the present invention has been described herein in
terms of certain preferred embodiments, those skilled in the art
will recognize that modifications and improvements may be made
without departing from the scope of the invention. For example,
although illustrated with support member 29, 53 in a lumen of the
shaft, in alternative embodiments, at least a section of the
support member is not in a lumen of the shaft, so that the support
member extends through the balloon interior without a portion of
the tubular shaft therearound. Moreover, while individual features
of one embodiment of the invention may be discussed or shown in the
drawings of the one embodiment and not in other embodiments, it
should be apparent that individual features of one embodiment may
be combined with one or more features of another embodiment or
features from a plurality of embodiments.
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