U.S. patent application number 10/246517 was filed with the patent office on 2003-07-03 for readily exchangeable perfusion dilatation catheter.
Invention is credited to McInnes, Peter R..
Application Number | 20030125763 10/246517 |
Document ID | / |
Family ID | 27413363 |
Filed Date | 2003-07-03 |
United States Patent
Application |
20030125763 |
Kind Code |
A1 |
McInnes, Peter R. |
July 3, 2003 |
Readily exchangeable perfusion dilatation catheter
Abstract
A perfusion-type dilatation catheter which can be rapidly
exchanged for another catheter without the need for exchange wires
or guidewire extension wires. The dilatation catheter has an
elongated catheter body with a distal guidewire port in the distal
end of the catheter and a proximal guidewire port at least 10 cm
but not more than 50 cm from the distal port. The catheter body has
a first inflation lumen which extends from the proximal end of the
catheter body to the interior of a dilatation balloon adjacent the
distal end of the catheter body. A second, much shorter inner lumen
is disposed between the proximal and distal guidewire ports and is
adapted to slidably receive a guidewire. A plurality of perfusion
ports are provided both proximal and distal to the balloon which
are in fluid communication with the second inner lumen so that when
the balloon is inflated within a patient's vascular system, blood
will flow through the proximal perfusion ports and the second inner
lumen and out the distal perfusion ports to minimize ischemic
conditions distal to the catheter. A stiffening member is disposed
within the catheter body proximal to the proximal guidewire port to
provide improved pushability. The distal portion of the inflation
lumen should have a transverse cross-sectional area of about 3 to
about 20.times.10-5 inch2 and should not be greater than one-third
the cross-sectional area of the perfusion lumen.
Inventors: |
McInnes, Peter R.; (Surrey,
GB) |
Correspondence
Address: |
FULWIDER PATTON LEE & UTECHT, LLP
HOWARD HUGHES CENTER
6060 CENTER DRIVE
TENTH FLOOR
LOS ANGELES
CA
90045
US
|
Family ID: |
27413363 |
Appl. No.: |
10/246517 |
Filed: |
September 17, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10246517 |
Sep 17, 2002 |
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08484268 |
Jun 7, 1995 |
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08484268 |
Jun 7, 1995 |
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08183574 |
Jan 18, 1994 |
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5516336 |
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08183574 |
Jan 18, 1994 |
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07888253 |
May 22, 1992 |
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07888253 |
May 22, 1992 |
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07541264 |
Jun 20, 1990 |
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07541264 |
Jun 20, 1990 |
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07476056 |
Feb 7, 1990 |
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Current U.S.
Class: |
606/194 |
Current CPC
Class: |
A61M 2025/107 20130101;
A61M 25/104 20130101; A61M 25/09 20130101; A61M 2025/0183 20130101;
A61M 2025/1097 20130101; A61M 2025/0063 20130101 |
Class at
Publication: |
606/194 |
International
Class: |
A61M 029/00 |
Claims
What is claimed:
1. An intravascular catheter for performing a vascular procedure
within a patient's vascular system, comprising: a) an elongated
catheter body having proximal and distal ends and an expandable
member proximally adjacent the distal end thereof and a relatively
short inner lumen adapted to receive a guidewire which extends
between a distal guidewire port provided in the distal end of the
catheter body and a proximal guidewire port which is provided in
the catheter body and which is disposed at least 10 cm but not more
than 50 cm from the distal guidewire port; b) at least one proximal
perfusion port located between the proximal guidewire port and the
expandable member and at least one distal perfusion port located
between the expandable member and the distal end of the catheter
body, the perfusion ports being in fluid communication with the
inner lumen adapted to receive a guidewire; and c) means to stiffen
a portion of the catheter body proximal to the proximal guidewire
port to provide the catheter with improved pushability.
2. The intravascular catheter of claim 1 wherein the expandable
member is an inflatable, relatively inelastic balloon suitable for
dilating a stenosis.
3. The intravascular catheter of claim 2 wherein the balloon is
formed from a plastic resin selected from the group consisting of
polyethylene and polyethylene terephthalate.
4. The intravascular catheter of claim 2 wherein the inflation
lumen extends distally from the proximal end of the catheter body
to the interior of the balloon.
5. The intravascular catheter of claim 1 wherein the means to
stiffen the catheter body proximal to the proximal guidewire port
is a rod tightly fitted within an inner lumen of the catheter body
which extends from the proximal end thereof to a location proximal
to the proximal guidewire port.
6. The intravascular catheter of claim 4 wherein the inflation
lumen has a D-shaped transverse cross-section and a thin wire
extends within the D-shaped inflation lumen to prevent the
retention of air bubbles in a corner of the inflation lumen.
7. The intravascular catheter of claim 1 wherein the proximal
guidewire port is disposed about 12 to about 40 cm from the distal
guidewire port.
8. The intravascular catheter of claim 1 wherein a slit is provided
in the wall of the catheter body defining at least in part the
second inner lumen which extends from the proximal guidewire port
to a location proximal to the proximal perfusion ports.
9. The intravascular catheter of claim 1 wherein there are about 6
to about 20 proximal perfusion ports in the catheter wall.
10. The intravascular catheter of claim 1 wherein there are about 4
to about 12 distal perfusion ports provided in the catheter
wall.
11. The intravascular catheter of claim 4 wherein the inflation
lumen in the distal portion of the catheter body has a
cross-sectional area of about 3 to about 20.times.10-5 inch2.
12. The intravascular catheter of claim 11 wherein the inflation
lumen has a cross-sectional area not greater than about 1/3 of the
cross-sectional area of the relatively short inner lumen adapted to
receive a guidewire.
13. The intravascular catheter of claim 11 wherein the inflation
lumen in the distal portion of the catheter body having a
cross-sectional area of about 3 to about 20.times.10-5 inch2 is
less than 30 cm in length.
14. The method of performing a vascular procedure in a patient's
vascular system, comprising: a) providing a vascular catheter
having an expandable member on the distal end thereof and a
relatively short inner lumen therein extending in a distal portion
of the catheter body between a distal guidewire port and a proximal
guidewire port about 10 to about 50 cm proximal from the distal
guidewire port and perfusion ports in the wall of the catheter body
in fluid communication with the short inner lumen between the
proximal guidewire port and the distal guidewire port in the distal
end of the catheter body; b) advancing the vascular catheter within
the patient's vascular system over a guidewire slidably disposed
within the relatively short inner lumen to a location within the
patient's vascular system; c) expanding the expandable member on
the vascular catheter to at least partially occlude the patient's
blood vessel at the location causing blood to flow through the
proximal perfusion ports and the second inner lumen and out the
distal perfusion ports; and d) contracting the expanded expandable
member to facilitate removal of the catheter from the patient.
15. The method of claim 11 wherein the guidewire is at least
partially removed from the portion of the second inner lumen
between the proximal and distal perfusion ports to avoid impeding
blood flow through the second inner lumen.
16. A method of claim 11 wherein: a) the catheter is removed from
the patient by holding the guidewire in place at a first location
outside of the patient and proximally moving the catheter over the
guidewire until the proximal guidewire port thereof is immediately
adjacent said first holding location; and b) holding the guidewire
at a second location outside of the patient adjacent the distal
guidewire port of the catheter and then removing the catheter from
the guidewire.
17. A method of claim 16 including: a) providing a second
dilatation catheter having an expandable member on the distal end
thereof and a relatively short inner lumen therein extending in a
distal portion of the catheter body between a distal guidewire port
and a proximal guidewire port about 10 to about 50 cm proximal from
the distal guidewire port and perfusion ports in the wall of the
catheter body in fluid communication with the short inner lumen
between the proximal guidewire port and the distal guidewire port
in the distal end of the catheter body; b) mounting the second
dilatation catheter onto the guidewire by passing the proximal end
of the guidewire through the second lumen until a portion thereof
extends out of the proximal guidewire port; c) holding the portion
of the guidewire extending out of the proximal port of the
catheter; and d) advancing the catheter over the guidewire into and
through the vascular system of the patient until the catheter is
positioned at a desired location therein.
18. An intravascular catheter for performing a vascular procedure
within a patient's vascular system, comprising: a) an elongated
catheter body having proximal and distal ends and an expandable
member proximally adjacent the distal end thereof and a relatively
short inner lumen adapted to receive a guidewire which extends
between a distal guidewire port provided in the distal end of the
catheter body and a proximal guidewire port which is provided in
the catheter body and which is disposed at least 10 cm but not more
than 50 cm from the distal guidewire port; b) at least one proximal
perfusion port located between the proximal guidewire port and the
expandable member and at least one distal perfusion port located
between the expandable member and the distal end of the catheter
body, the perfusion ports being in fluid communication with the
inner lumen adapted to receive a guidewire; and c) means to stiffen
a portion of the catheter body proximal to the proximal guidewire
port to provide the catheter with improved pushability.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application
Ser. No. 07/476,056, filed on Feb. 7, 1990.
BACKGROUND OF THE INVENTION
[0002] This invention generally relates to a dilatation catheter
for angioplasty procedures such as percutaneous transluminal
coronary angioplasty (PTCA).
[0003] In PTCA procedures, a dilatation catheter having an
inflatable relatively inelastic balloon on the distal end thereof
is advanced through a patient's arterial system until the balloon
crosses the atherosclerotic lesion to be dilated. The balloon is
inflated to a predetermined size with radiopaque liquid at
relatively high pressures (e.g., 8 atmospheres) to dilate the
stenotic region and then the balloon is deflated so that the
catheter can be removed and blood flow resumed.
[0004] Usually a guiding catheter having a preformed distal end is
first percutaneously introduced into the patient's arterial system
and advanced therein until the distal tip of the guiding catheter
is disposed in the appropriate ostium of the patient's coronary
artery. A guidewire is preloaded within a dilatation catheter and
both are advanced through the previously positioned guiding
catheter to the distal end thereof. The guidewire is first advanced
out of the guiding catheter into the patient's coronary anatomy
until the distal end of the guidewire crosses the stenotic region
to be dilated. The dilatation catheter is then advanced over the
guidewire, with the guidewire slidably disposed within an inner
lumen of the catheter until the inflatable balloon is positioned
within the stenosis. The balloon is inflated to a relatively high
pressure to dilate the stenosis and then deflated and removed over
the guidewire. For a detailed description of procedures, reference
is made to U.S. Pat. No. 4,332,254 (Lundquist), U.S. Pat. No.
4,323,071 (Simpson-Robert), U.S. Pat. No. 4,439,185 (Lundquist),
U.S. Pat. No. 4,468,224 (Enzmann et al.), U.S. Pat. No. 4,516,972
(Samson), U.S. Pat. No. 4,538,622 (Samson, et al.), U.S. Pat. No.
4,554,929 (Samson et al.), U.S. Pat. No. 4,569,347 (Frisbie), U.S.
Pat. No. 4,571,240 (Samson et al.), U.S. Pat. No. 4,638,805
(Powell), U.S. Pat. No. 4,748,982 (Horzewski et al.), all of which
are hereby incorporated herein in their entirety by reference
thereto.
[0005] Efforts have been made to develop dilatation catheters which
perfuse blood through an inner lumen of the catheter which
traverses the interior of the balloon when the balloon is inflated
during angioplasty procedures in order to avoid ischemic conditions
distal to the inflated balloon. For example, dilatation catheters
providing perfusion capabilities are described in U.S. Pat. No.
4,423,725 (Baran et al.) and U.S. Pat. No. 4,790,315 (Mueller, Jr.
et al.) which are incorporated herein by reference thereto. See
also, U.S. Pat. No. 4,581,017 (Sahota). However, these perfusion
dilatation catheters generally have relatively large deflated
profiles and as a result they frequently are not employed in those
situations where the stenoses to be treated are deep within the
patient's coronary anatomy.
[0006] Additionally, in instances where there is an acute or sudden
blockage of the arterial passageway after dilatation of a stenotic
region, conventional dilatation non-perfusion type catheters must
first be removed from the patient before a perfusion-type
dilatation catheter can be advanced over the guidewire in place
within the patient. Usually, such catheter exchanges require the
use of an exchange wire or extension wire such as described in U.S.
Pat. No. 4,827,941 (Taylor et al.), which can add considerable time
and complexity to a procedure frequently performed under emergency
conditions.
[0007] What has been needed and heretofore unavailable is a
perfusion-type dilatation catheter which can quickly and easily be
introduced into a patient's arterial system and which has
sufficient pushability to be advanced deep within the patient's
vasculature. The present invention satisfies this need.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a dilatation catheter
which can be readily exchanged without the need for extension wires
or for the replacement of the guidewire with an exchange wire and
which can also perfuse blood distal to the catheter when a vascular
procedure is being performed within the blood vessel which
otherwise blocks the flow of blood through.
[0009] A catheter in accordance with the invention generally has an
elongated catheter body with an inflatable, relatively inelastic
balloon near the distal end thereof. The catheter body has a first
elongated inner lumen extending from the proximal end of the
catheter body to the interior of the inflated balloon near the
distal end thereof to deliver inflation fluid to the interior of
the balloon. A second, much shorter inner lumen extends within the
distal portion of the catheter body between a proximal guidewire
port and a distal guidewire port provided in the distal end of the
catheter body. The distal guidewire port is in the very distal tip
of the catheter body and the proximal guidewire port is at least 10
cm but not more that about 50 cm from the distal guidewire port.
The second, much shorter lumen within the catheter body is adapted
to slidably receive a guidewire to facilitate the advancement of
the catheter over the guidewire into the patient's coronary
anatomy.
[0010] At least one proximal perfusion port is provided in the
catheter body between the proximal guidewire port and the proximal
end of the balloon and at least one distal perfusion port is
provided in the catheter body between the distal end of the balloon
and the distal end of the catheter body. Both the proximal and
distal perfusion ports are in fluid communication with the second,
shorter lumen disposed within the catheter body so that the blood
flows distal to the catheter when the balloon is inflated during
the vascular procedure. The number, size and location of the
perfusion ports can be varied depending upon the blood flow
required, the size of the catheter and the size of the inner lumen.
Typically, there may be 6 to 20 perfusion ports proximal to the
balloon and about 4 to 12 perfusion ports distal to the balloon. In
a preferred embodiment 10 ports are provided proximal to the
balloon and 4 are provided distal to the balloon.
[0011] The cross-sectional area of the inflation lumen in the last
30 cm of the distal portion of the catheter body, preferably in the
last 10 cm the inflation lumen proximal to the balloon, is at least
about 3 to about 20.times.10-5 inch 2 and should not be greater
than about one-third of the cross-sectional area of the perfusion
lumen. This reduces considerably the catheter profile, allowing the
catheter to be advanced much deeper into a patient's coronary
vasculature, yet maintains adequate inflation and deflation times
(e.g. less that about 30 seconds preferably less than about 20
seconds). The proximal end of the catheter body is provided with an
adapter with at least one arm for the delivery of inflation fluid
from a high pressure source thereof such as a syringe to the
proximal end of the inflation lumen leading to the interior of the
balloon for inflation purposes.
[0012] Preferably, the catheter wall which defines at least in part
the second, shorter, guidewire-receiving lumen disposed within the
catheter body is provided with a slit which extends from the
proximal guidewire port to a location proximal to the section
containing the proximal perfusion ports. The purpose of this slit,
as described in U.S. Pat. No. 4,748,982 (Horzewski et al.) which
has been previously incorporated herein, allows the guidewire to be
pulled out of a significant portion of the second lumen to increase
the ease in which catheters can be exchanged.
[0013] The portion of the elongated catheter body proximal to the
proximal guidewire port is provided with a stiffening member such
as a rod or wire which increases the pushability of the catheter
and thereby allows for more distal advancement of the catheter into
the patient's coronary anatomy than previous perfusion-type
catheters.
[0014] In the performance of an angioplasty procedure utilizing the
catheter assembly of the invention, it is preferred to preload the
guidewire within the second shorter lumen of the catheter with the
distal tip of the guidewire extending out of the distal tip of the
catheter, and then advance the combined assembly through a guiding
catheter previously disposed within the patient's vasculature with
the distal tip of the guiding catheter disposed with the ostium of
the patient's coronary artery. The guidewire is first extended out
of the distal end of the guiding catheter into the patient's
coronary artery until the distal tip of the guidewire crosses the
stenotic region to be dilated. The dilatation catheter is then
advanced out of the guiding catheter over the guidewire until the
balloon on the dilatation catheter is positioned across the
stenosis. The balloon is then inflated with the radiopaque liquid
as conventionally practiced to dilate the stenosis.
[0015] An alternate procedure which has been found suitable
comprises first advancing the guidewire through the guiding
catheter and into the desired location within the patient's
coronary anatomy and then mounting the dilatation catheter of the
invention on the proximal end of the guidewire and advancing the
catheter over the wire to the desired location within the patient's
coronary arteries.
[0016] When the balloon is inflated, it occludes the artery and
blocks normal blood flow therethrough. However, blood flows through
the proximal perfusion ports, through the shorter second lumen, and
then out the distal perfusion ports and the distal guidewire port
located in the catheter body distal to the balloon. To maximize
blood flow through the second lumen, it is preferred to withdraw
the guidewire sufficiently from the dilatation catheter so that the
distal portion of the guidewire remains in the second lumen but
proximal to the portion of the second lumen between the proximal
and distal perfusion ports. When the dilatation has been completed,
the guidewire can then be advanced back through the second lumen
and out the distal end thereof so that it crosses the stenosis.
[0017] In the event of an abrupt reclosure when the dilatation
catheter is deflated, such as from a dissected lining, the balloon
can be inflated in the stenotic region so as to maintain the
patency of the artery. The artery may then be held open while blood
perfuses therethrough for a long enough period to allow the
dissected lining to be resecured to the blood vessel wall by
natural healing or to allow for surgical procedures to be initiated
to correct the abrupt reclosure, such a bypass surgery.
[0018] Should the catheter in place need to be replaced with
another catheter, for example when the inflated diameter of the
balloon on the catheter in place is too small to completely dilate
a stenosis, a second catheter should then be inserted to complete
the dilation. In this instance, the catheter of the invention can
be readily replaced by holding onto the guidewire extending out the
proximal end of the guiding catheter and pulling on the dilatation
catheter to remove it from the patient. A second dilatation
catheter of essentially the same construction but with a larger
diameter balloon may then be mounted on the proximal end of the
guidewire and then advanced over the guidewire into the stenosis
for further dilation.
[0019] A similar situation arises when a second stenosis distal to
the first stenosis needs to be dilated and the balloon on the
catheter used to dilate the first stenosis is too large for the
distal region. The same procedures may be followed to advance a
catheter having a smaller balloon to the more distal stenosis.
[0020] The dilatation catheter in accordance with the present
invention can be advanced deeply within the patient's vascular
system, much further than prior perfusion catheters due to the
increased pushability of the catheter. Thus, the catheter of the
present invention allows for the long-term dilatation of stenosis
which the prior perfusion catheters were unable to reach.
Additionally, when a catheter in accordance with the present
invention needs to be replaced with another catheter, such catheter
exchanges can be quickly and very easily performed without the need
for exchange wires or extension wires required with the prior art
dilatation catheters. These and other advantages of the present
invention will become more apparent from the following detailed
description thereof when taken in conjunction with the attached
exemplary drawings
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is an elevation view partially in section of a
dilatation catheter embodying features of the invention;
[0022] FIG. 2 is a transverse cross-sectional view taken along the
lines 2-2 shown in FIG. 1;
[0023] FIG. 3 is a transverse cross-sectional view taken along the
lines 3-3 shown in FIG. 1;
[0024] FIG. 4 is a transverse cross-sectional view taken along the
lines 4-4 shown in FIG. 1;
[0025] FIG. 5 is a transverse cross-sectional view taken along the
lines 5-5 shown in FIG. 1;
[0026] FIG. 6 is a transverse cross-sectional view taken along the
lines 6-6 shown in FIG. 1;
[0027] FIG. 7 is a transverse cross-sectional view taken along the
lines 7-7 shown in FIG. 1;
[0028] FIG. 8 is a longitudinal, center line, cross-sectional view
taken through the transition region of the catheter shown in FIG. 1
illustrating the extension of the guidewire through a proximal
guidewire port and into an inner lumen of the dilatation
catheter;
[0029] FIG. 9 is a partial elevational view, partially in section
of an alternative dilatation catheter embodying features of the
invention;
[0030] FIG. 10 is a cross-sectional view taken along the lines
10-10 shown in FIG. 9;
[0031] FIG. 11 is a cross-sectional view taken along the lines
11-11 shown in FIG. 9; and
[0032] FIG. 12 is a cross-sectional view taken along the lines
12-12 shown in FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The present invention is directed to a vascular catheter 10
having a elongated catheter body 11 with an inflatable balloon 12
near the distal end thereof. A first inner lumen 13 extends through
a substantial portion of the catheter body 11 and is in fluid
communication with the interior of the balloon 12. An adapter 14 is
provided at the proximal end of the catheter body 11 which is in
fluid communication with the first inner lumen 13 to direct
inflation fluid from a high pressure source such as a syringe pump
(not shown) to the interior of balloon 12.
[0034] A second lumen 16 is provided in a distal portion of the
catheter 10 which remains within the patient during angioplasty or
other vascular procedures. The second lumen 16 is much shorter than
the first lumen and extends between a proximal guidewire port 17
and a distal guidewire port 18 which is located at the distal tip
of the catheter body. The proximal guidewire port 17 is located
about 10 to about 50 cm, preferably about 12 to about 40 cm, from
the distal guidewire port 18. During the angioplasty procedures,
the guidewire 20 is slidably disposed within the second inner lumen
16.
[0035] Proximal perfusion ports 21 are provided in the catheter
body 11 between the proximal end of the balloon 12 and the proximal
guidewire port 17 and distal perfusion ports 22 are provided
between the distal end of the balloon and the distal end of the
catheter body 11. Perfusion ports 21 and 22 pass through the wall
of the catheter body 11 which defines at least in part the second
inner lumen 16 and therefore are in fluid communication
therewith.
[0036] The guidewire 20 generally includes a core member 23 and a
flexible body such as a helical coil 24 on the distal portion of
the core member. A rounded plug 25 is provided at the distal tip of
the core to prevent traumatic engagement with the arterial lining.
During angioplasty or other vascular procedures, the proximal
guidewire port 17 remains within the guiding catheter, and the core
member 23 of the guidewire 20 extends out of the proximal guidewire
port and runs generally parallel to the catheter body within the
guiding catheter (not shown).
[0037] Stiffening rod 26 is disposed within a third lumen 27
provided in the catheter body 11 proximal to the proximal guidewire
port 17 and generally extends to the proximal end of the catheter
body 11. For ease of manufacturing, the third lumen 27 and the
second inner lumen 16 are essentially the same lumen with a plug 28
provided therein proximately adjacent the proximal guidewire port
17. Preferably the distal portion of the plug 28 is in the form of
a ramp 30 which can guide the guidewire 20 into or out of the
second inner lumen 16. The wall of the catheter body 11 defining
the inner lumen 16 is provided with a slit 31 from the proximal
guidewire port 17 to a location proximal to the proximal perfusion
port 21 through port 17.
[0038] The first inner lumen 13 is preferably provided with a small
diameter wire member 32 which prevents the retention of air bubbles
at the corners of the D-shaped first lumen. The wire member 31
preferably does not extend along essentially the entire length of
the inflation lumen 13.
[0039] The various components of the catheter of the present
invention can be made from conventional materials. Catheter body 11
can be extruded or otherwise formed from plastic resins such as
polyethylene and polyesters (e.g., Hytrel) and the balloon can be
formed from polyethylene or polyethylene terephthalate resins. The
core 23 of the guidewire 20 can be made of stainless steel and the
coil 24 can be made of a more highly radiopaque material such as
platinum, tungsten, palladium, ruthenium, rhenium and alloys
thereof. A wide variety of other suitable materials can also be
used for these components.
[0040] For coronary angioplasty procedures, the outer diameter of
the catheter body 11 proximal to the perfusion section can
typically range from about 0.035 to about 0.05 inch (0.89-1.30 mm.)
and the perfusion section thereof can range from about 0.04 to 0.06
inch (1.02-1.52 mm.). Inflatable balloon diameters can range from
about 1.5 to about 4.5 mm. The stiffening element is a rod or wire
preferably with a circular transverse cross-section ranging in
diameter from about 0.015 to about 0.025 inch (0.38-0.64 mm.). The
diameter of the guidewire lumen 16 in the perfusion section of the
catheter body 11 may vary from about 0.02 to about 0.045 inch
(0.51-1.14 mm.), but the opening in the distal tip of the catheter
may range from about 0.015 to about 0.025 inch (0.38-0.064 mm). The
overall length of the catheter body 11 from the distal tip to the
adapter 14 may be about 130 to about 150 cm. The aforesaid
dimensions are believed to be suitable for most coronary
angioplasty procedures. Angioplasty procedures at other locations
and catheters for other procedures (e.g., atherectomy procedures)
may require dimensions different than those described above.
[0041] FIGS. 8-15 illustrate an alternate embodiment which provides
a rapid exchange dilatation catheter with perfusion characteristics
with an improved low profile distal portion. The proximal portion
of the catheter and the balloon 12 and portions distal thereto are
essentially the same as that shown in FIGS. 1-7. The improvements
of the embodiment shown in FIGS. 8-11 involve the distal portion of
the catheter between the proximal guidewire port 17 and the balloon
12 wherein the ratio of the cross sectional area of the inflation
lumen 13 to the cross-sectional area of the perfusion lumen 16 is
controlled so that the former lumen is not greater than about
one-third of the latter. Preferably, the inflation lumen 13 is
D-shaped or crescent-shaped along its entire length, whereas the
perfusion lumen 16 is essentially circular along its length. A
proximal portion of the perfusion lumen, e.g., the first 24 cm may
however, be shaped to reduce the profile in this section as shown
in FIG. 4. Additionally, the inflation lumen should have a
cross-sectional area of about 3 to about 20.times.10-5 inch 2.
However, in order to maintain reasonable inflation and deflation
times (e.g. less than about 30 seconds, preferably less than about
20 seconds) the length of the inflation lumen having the aforesaid
cross-section should not exceed 20 cm. The inflation lumen in the
catheter body 11 leading to the portion having the smaller
transverse dimensions is typically about 65.times.10-5 inch2. The
details for the guidewire lumen and the perfusion lumen are
described with the embodiment shown in FIGS. 1-7. Typical
dimensions for the cross-section shown in FIG. 9 include a height
of about 0.007 inch and a base of about 0.026 inch for the
inflation lumen, a radius of about 0.019 inch for the perfusion
lumen, all thickness of about 0.005 inch at location A between the
perfusion lumen and the exterior of the catheter body 11 and a wall
thickness of about 0.006 inch at location B between the perfusion
lumen and the inflation lumen. The outer diameter of the catheter
body is about 0.052 inch, which is to be compared to an outer
diameter of about 0.057 inch for the embodiment shown in FIGS.
1-7.
[0042] The catheter of this embodiment has great pushability and
perfusion of blood to the distal portion of the coronary artery.
The lower profile and enhanced pushability allows the catheter to
be advanced much farther into a patient's coronary anatomy than
prior perfusion catheters.
[0043] While the present invention has been described herein in
terms of certain specifically preferred embodiments specifically
directed to coronary angioplasty procedures, various modifications
and improvements can be made without departing from the scope of
the invention.
* * * * *