Title: Reduced slippage balloon catheter and method of using same
Abstract: A balloon catheter having a balloon with a reduced slippage lubricious coating, and a method of performing a medical procedure such as a balloon dilatation procedure in a patient's blood vessel. The second coating (i.e., the balloon coating) is lubricious to facilitate movement of the catheter in the patient's body lumen, yet has sufficiently low lubricity such that the slippage of the inflated balloon from a desired site within the blood vessel is reduced compared to a balloon coated with the first lubricious coating.
Patent Number: 7,025,752 Issued on 04/11/2006 to Rice, et al.
| Inventors:
|
Rice; Cheryl (San Diego, CA);
Chang; Rosabel (San Jose, CA);
Duchamp; Jacky G. (Campbell, CA)
|
| Assignee:
|
Advanced Cardiovascular Systems, Inc. (Santa Clara, CA)
|
| Appl. No.:
|
288783 |
| Filed:
|
November 6, 2002 |
| Current U.S. Class: |
604/265 |
| Current Intern'l Class: |
A61M 5/32 (20060101) |
| Field of Search: |
606/108,192,194,195,198
604/960.1,103.06,172,264,265
623/146,111
|
References Cited [Referenced By]
U.S. Patent Documents
| 4459317 | Jul., 1984 | Lambert.
| |
| 5503631 | Apr., 1996 | Onishi et al.
| |
| 5693014 | Dec., 1997 | Abele et al.
| |
| 6261630 | Jul., 2001 | Nazarova et al.
| |
| 6306144 | Oct., 2001 | Sydney et al.
| |
| 6673053 | Jan., 2004 | Wang et al.
| |
| 6866649 | Mar., 2005 | Ferrera et al.
| |
| 2002/0022849 | Feb., 2002 | Sydney et al.
| |
| Foreign Patent Documents |
| 0 778 012 | Jun., 1997 | EP.
| |
| WO 94/2766/5 | Dec., 1994 | WO.
| |
| WO 97/3167/4 | Sep., 1997 | WO.
| |
| WO 00/6782/8 | Nov., 2000 | WO.
| |
Primary Examiner: Truong; Kevin T.
Attorney, Agent or Firm: Fulwider Patton LLP
Claims
What is claimed is:
1. A balloon catheter, comprising:
a) an elongated shaft having a proximal end, a distal end, and an inflation lumen,
and having a first lubricious coating with a first amount per unit area of lubricious
material on at least a portion of the shaft; and
b) a balloon on a distal shaft section having an interior in fluid communication
with the inflation lumen, and having a second lubricious coating with a second
amount per unit area of lubricious material on at least a portion of the balloon,
the second amount per unit area being not more than about 2.5% to about 3% of the
first amount per unit area.
2. The balloon catheter of claim 1 wherein the shaft includes a distal tip section
having at least a portion distal to the balloon and coated with the second lubricious coating.
3. The balloon catheter of claim 2 wherein the distal tip section is formed by
a distal tip member secured to a distal end of a section of the shaft proximal thereto.
4. The balloon catheter of claim 1 wherein the shaft comprises an outer tubular
member defining the inflation lumen and an inner tubular member defining a guidewire
receiving lumen, and the first lubricious coating is on an outer surface of a proximal
and a distal section of the outer tubular member.
5. The balloon catheter of claim 1 wherein the second lubricious coating extends
along the entire length of an outer surface of the balloon.
6. The balloon catheter of claim 1 wherein the lubricious material of the first
and second coating is the same.
7. The balloon catheter of claim 1 wherein the lubricious material of the first
and second coating is polyethylene oxide.
8. The balloon catheter of claim 1 wherein the second amount per unit area of
lubricious material is about 1% to about 2.5% of the first amount per unit area.
9. The balloon catheter of claim 1 wherein the balloon coated with the second
lubricious coating has a slip angle which is less than a slip angle of a bare balloon
and greater than a slip angle of a balloon coated with the first lubricious coating.
10. The balloon catheter of claim 1 wherein the balloon coated with the second
lubricious coating has a slip angle which is greater than a slip angle of a balloon
coated with a lubricious coating having an amount per unit area of the lubricious
material which is about 5% to about 100% of the first amount per unit area.
Description
BACKGROUND OF THE INVENTION
This invention generally relates to catheters, and particularly protective sheaths
for intravascular catheters for such as balloon catheters used in percutaneous
transluminal coronary angioplasty (PTCA) or for the delivery of stents.
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 lesion 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 overexpand the artery wall. After
the balloon is finally deflated, blood flow resumes through the dilated artery
and the dilatation catheter and the guidewire can be removed therefrom.
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. A tubular cover formed of synthetic or
natural material may be present on an outer or inner surface of the stent. 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.
An essential step in effectively performing a PTCA procedure is properly positioning
the balloon catheter at a desired location within the coronary artery. 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
This invention is directed to a balloon catheter having a balloon with a reduced
slippage lubricious coating, and a method of performing a medical procedure such
as a balloon dilatation procedure in a patient's blood vessel.
The balloon catheter of the invention generally includes an elongated shaft having
a proximal end, a distal end, an inflation lumen, and a first lubricious coating
with a first amount per unit area of lubricious material on at least a portion
of the shaft, and a balloon on a distal shaft section having an interior in fluid
communication with the inflation lumen, and a second lubricious coating on at least
a portion of the balloon, the second lubricious coating having a second amount
per unit area of lubricious material which is less than the first amount per unit
area of lubricious material. In a presently preferred embodiment, the shaft includes
a distal tip section, which in one embodiment is formed of a separate distal tip
member, having at least a portion distal to the balloon and coated with the second
lubricious coating. In one embodiment, the shaft comprises an outer tubular member
defining the inflation lumen, and an inner tubular member defining a guidewire
receiving lumen extending in at least a distal portion of the outer tubular member,
and the first lubricious coating is on an outer surface of a proximal and a distal
section of the outer tubular member defining an outer surface of the catheter.
The second lubricious coating on the balloon preferably extends along the entire
length of an outer surface of the balloon, although in alternative embodiments,
the second lubricious coating may be on less than the entire outer surface of the
balloon, and for example may be on intermittent portions of the balloon outer surface.
In one embodiment, the lubricious material of the first and second coating is
a hydrophilic material, and in a presently preferred embodiment, is a polyethylene
oxide based lubricious coating. However, a variety of suitable lubricious materials
can be used including hydrophobic materials. In a presently preferred embodiment,
the lubricious material of the first and second coatings is the same lubricious
material, but, in accordance with the invention, is applied so that the balloon
is coated with a smaller amount per unit area of the lubricious material, and thus
a less lubricious coating, than at least the part of the shaft proximal thereto.
The second coating (i.e., the balloon coating) is lubricious to facilitate movement
of the catheter in the patient's body lumen, yet has sufficiently low lubricity
such that the slippage of the inflated balloon from a desired site within the blood
vessel is reduced compared to a balloon coated with the first lubricious coating.
The coated balloon inflates into contact with, and remains at least partially in
contact with a stenosed section of the blood vessel. Thus, the balloon catheter
provides for improved dilatation of the desired region of the blood vessel by reducing
the tendency of the lubriciously coated balloon to slip proximally or distally
from the stenosed section of the blood vessel. The first lubricious coating on
the balloon is relatively highly lubricious and thus facilitates movement of the
catheter in the body lumen.
The second coating has a relatively small amount of lubricious material, to thereby
provide a balloon surface which is more lubricious than a bare (non-coated) balloon,
yet which has an insubstantial amount of slippage when inflated into contact with
the blood vessel. Preferably, the second amount of lubricious material per unit
area is not more than about 2.5% to about 3% of the first amount per unit area,
and is most preferably about 1% to about 2.5% of the first amount per unit area.
The coatings can be applied using a variety of suitable methods including wiping,
spraying, and dipping solutions of the lubricious material onto the outer surface
of at least a portion of the shaft and at least a portion of the balloon. The solutions
on the catheter are typically cured to produce the lubricious coatings on the catheter.
The cured lubricious coatings typically consist of the lubricious material and
a matrix material. In a presently preferred embodiment, the first and second solutions
which are applied to the catheter to form the first and second coatings, respectively,
have an amount of lubricious material in the same proportion as in the cured coatings
(i.e., the concentration of lubricious material in the second solution is not more
than about 2.5% to about 3% of the concentration of lubricious material in the
first solution). In a presently preferred embodiment, the second solution is prepared
by diluting the first solution with additional solvent, with the absolute amount
of lubricious material being about the same in the two solutions. As a result,
after removal of the solvents during curing of the coatings on the balloon and
shaft, the concentration of lubricious material (grams of lubricious material per
gram of cured coating) of the second cured coating on the balloon is the about
the same as the concentration of lubricious material of the first cured coating
on the shaft. However, in a presently, preferred embodiment, approximately the
same amount of solution is applied to the shaft as to the balloon, so that the
resulting cured coatings on the shaft and the balloon have an amount (mass) of
lubricious material per unit area (gm/in
2) in the same proportion as
the amount of lubricious material in the two solutions (i.e., the solution of lubricious
material applied to the balloon has a concentration of lubricious material which
is not more than about 2.5% to about 3% of the concentration of lubricious material
in the solution of lubricious material applied to the shaft, and the resulting
mass of lubricious material per unit area in the cured second lubricious coating
on the balloon is not more than about 2.5% to about 3% of the mass of lubricious
material per unit area in the cured first lubricious coating on the shaft. However,
it should be understood that there are a variety of ways of forming the coatings
on the shaft and balloon with the desired relative amounts of lubricious material,
including applying different amounts of lubricious solution, and applying lubricious
solutions which do not have an amount of lubricious material in the same proportion
as the amount of lubricious material in the resulting cured coatings on the shaft
and the balloon.
The balloon coated with the second lubricious coating has a slip angle which
is less than a slip angle of a bare (non-coated) balloon and greater than a slip
angle of a balloon coated with the first lubricious coating. The slip angle is
the critical angle at which the coated workpiece will slip out of position. A less
lubricious surface has a higher slip angle than a more lubricious surface. A fixture
for measuring the slip angle generally comprises a polymeric tube, and specifically
a polyvinyl alcohol and dimethyl sulfoxide tube, which simulates a blood vessel,
and a pusher with a weight which is on an outer surface of the tube and which can
be oriented at different angles relative to the polymeric tube. The balloon is
placed in the tube, with the angle at which the pusher contacts the tube simulating
the angle of a lesion in a blood vessel, and the angle of the pusher is increased
until the balloon slips longitudinally out of position during inflation of the
balloon in the tube. Thus, the pusher squeezing on the balloon causes the balloon
to slip longitudinally, and the higher the angle at which this slipping first occurs,
the less likely the balloon is to slip out of position during inflation of the
balloon in a patient's blood vessel (i.e., the relatively less lubricious the balloon
outer surface). In a presently preferred embodiment, two measurements are made,
namely, one with the pusher aligned at the balloon distal marker at the distal
end of the balloon central working length, and another with the pusher aligned
1 mm proximal to the distal marker. Using this procedure the slip angle can be
measured for various coatings to compare the effect of the relative lubricity of
the various coatings on balloon slippage. The slip angle of the balloon coated
with the second lubricious coating (i.e., the minimum angle of the pusher at which
the balloon begins to slip in the polymeric tube) is about 4 to about 10 degrees,
preferably about 8 to about 10 degrees, and the slip angle of a bare balloon is
about 10 to about 15 degrees, preferably about 12 to about 15 degrees, and the
slip angle of a balloon coated with the first lubricious coating is about 1 to
about 7 degrees, preferably about 2 to about 6 degrees. It should be noted that
at a relatively high angle of about 20 degrees the pusher begins to pinch the balloon
and prevent the balloon from slipping longitudinally in the polymeric tube, so
that a slip angle above 20 degrees cannot be measured with the slip angle fixture
described above.
In a method of performing a medical procedure, a balloon catheter is advanced
within a patient's blood vessel to a desired position at a stenosed section, the
balloon catheter having a first lubricious coating with a first amount per unit
area of lubricious material on at least a portion of the shaft and a second lubricious
coating with a second smaller amount per unit area of lubricious material on at
a least portion of the balloon, and the balloon is inflated so that the balloon
working length contacts and dilates the stenosed section of the blood vessel. The
coated surface of the balloon inflates into direct contact with the blood vessel
wall/lesion, and the second coating limits or prevents the balloon from slipping
longitudinally out of position. Preferably, the balloon catheter of the invention
has a balloon which is at least about 40% less likely to slip out of position in
a patient's body lumen during dilatation of a lesion than a balloon catheter having
a balloon with the same lubricious coating as the shaft. In one embodiment, due
to the limited amount of slippage of the balloon, a substantial portion of the
inflated balloon working length remains in contact with the stenosed section of
the blood vessel during the dilation. After the dilation, the balloon is deflated,
and the catheter is repositioned or withdrawn from the blood vessel. The lubricious
coatings on the catheter facilitate repositioning or withdrawing the deflated balloon
catheter from the blood vessel.
The balloon catheter can be used for a variety of procedures including coronary
or peripheral dilatation, drug delivery, intravascular prosthesis delivery and
the like. The balloon catheter can have a variety of convention configurations
including an over-the-wire type design, or a rapid exchange type design. Rapid
exchange catheters generally comprise a distal guidewire port in a distal end of
the catheter, a proximal guidewire port in a distal shaft section distal of the
proximal end of the shaft and typically spaced a substantial distance from the
proximal end of the catheter, and a short guidewire lumen extending between the
proximal and distal guidewire ports in the distal section of the catheter.
The balloon catheter of the invention provides for improved dilatation of a patient's
blood vessel, due to the first and second lubricious coatings on the shaft and
balloon, respectively. The coated balloon surface has a sufficiently low lubricity
to minimize the slippage of the inflated balloon out of position at the lesion
during the dilatation, yet sufficiently high lubricity to facilitate movement of
the catheter within the blood vessel. 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
FIG. 1 is an elevational view, partially in section, of a balloon catheter embodying
features of the invention, in a patient's body lumen.
FIGS. 2 and 3 are transverse cross sectional views of the balloon catheter
shown in FIG. 1, taken along lines 2—2 and 3—3, respectively.
FIG. 4 is an enlarged, partially in section, view of the distal end of the balloon
catheter shown in FIG. 1, with the balloon inflated during dilatation of the body lumen.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates an over-the-wire type balloon catheter
10 embodying
features of the invention. Catheter
10 generally comprises an elongated
catheter shaft
12 having an outer tubular member
14 and an inner
tubular member
16. Inner tubular member
16 defines a guidewire lumen
18 configured to slidingly receive a guidewire
20, and the coaxial
relationship between outer tubular member
14 and inner tubular member
16
defines annular inflation lumen
22, as best shown in FIG. 2 illustrating
a transverse cross section view of the distal end of the catheter shown in FIG.
1, taken along line
2—
2. An inflatable balloon
24 disposed
on a distal section of catheter shaft
12 has an elongated cylindrical expandable
working section, a proximal skirt section
25 sealingly secured to the distal
end of outer tubular member
14 and a distal skirt section
26 sealingly
secured to the distal end of inner tubular member
16, so that its interior
is in fluid communication with inflation lumen
22. A distal tip
27
defining the distal end of the guidewire lumen
18 is located distal to the
balloon
24. In the embodiment of FIG. 1, the distal tip
27 is a separate
member butt joined to the distal end of the inner tubular member
16, with
the butt joint located at the distal end of the balloon distal skirt section
26.
However, in an alternative embodiment (not shown), the distal tip
27 and
inner tubular member
16 are an integral, one-piece unit, so that the distal
tip
27 is defined by the exposed outer surface of the distal end of the
inner tubular member
16 distal to the distal end of the balloon
24.
A variety of suitable distal tip configurations can be used as are conventionally
known, including a distal tip having a proximal end surrounded by and bonded to
another component of the catheter. An adapter
28 at the proximal end of
catheter shaft
12 is configured to provide access to guidewire lumen
18,
and to direct inflation fluid through arm
29 into inflation lumen
22.
FIG. 1 illustrates the balloon
24 in a low profile tubular configuration
prior to complete inflation. The distal end of catheter
10 may be advanced
to a desired region of the patient's blood vessel
30 in a conventional manner,
and balloon
24 inflated to expand the balloon
24 into contact with
the lesion to dilate the stenosed section
31 of the blood vessel, and the
balloon deflated and the catheter repositioned in the blood vessel or withdrawn
therefrom. FIG. 3 illustrates a transverse cross section view of the distal end
of the catheter shown in FIG. 1, taken along line
3—
3.
The outer surface of the outer tubular member
14 has a first lubricious
coating
40, and the outer surface of the balloon
24 has a second
lubricious coating
41. In the embodiment of FIG. 1, the first lubricious
coating
40 extends the entire length of the exposed outer surface of the
outer tubular member
14 defining an outer surface of the catheter, and the
second lubricious coating
41 extends the entire length of the balloon
24
and over the exposed outer surface of the distal tip
27. Thus, the portion
of the outer tubular member
14 covered by and bonded to the proximal skirt
section
25 of the balloon is not coated with the lubricious coating
40.
The thickness of the coatings
40,
41 are exaggerated in the figures
for ease of representation. In the embodiment of FIG. 1, the thicknesses of the
cured coating
40 on the outer tubular member
14 is thicker than the
thickness of the cured coating
41 on the balloon
24.
The second lubricious
41 coating has an amount per unit area of lubricious
material which is less than the amount per unit area of lubricious material in
the first lubricious coating
40, so that the first lubricious coating
40
on the outer tubular member
14 is more highly lubricious than the second
lubricious coating
41 on the balloon
24. In a presently preferred
embodiment, the first coating
40 is applied by applying a first solution
of the lubricious material on the exposed outer surface of the outer tubular member
14 after the catheter has been assembled (i.e., the balloon secured to the
inner and outer tubular members). Similarly, the second coating
41 is provided
on the balloon by applying a second solution the lubricious material on the outer
surface of the balloon
24 and the tip
27. Preferably, the concentration
of lubricious material in the second solution is not more than about 2.5% to about
3% of the concentration in the first solution. In a presently preferred embodiment,
the concentration of the first solution is about 1.0 to about 1.3 wt. % lubricious
material, and the concentration of the second solution is about 0.01 to about 0.03
wt. % lubricious material. The solutions are cured, as for example by drying and/or
ultraviolet (UV) curing, to form the coatings
40,
41 on the catheter.
In one embodiment, the lubricious solutions comprise polyethylene oxide and trimethoylol
propane triacrylate in benzophenone, hydrophenyl ketone and 1-hydroxycyclohexyl
phenyl ketone.
The second lubricious coating is less lubricious than the first lubricious coating
(i.e., it is less lubricious than a coating having 100% of the first amount of
lubricious material), and is preferably less lubricious than a coating having as
little as about 5% to about 10% of the first amount of lubricious material). Thus,
the second lubricious coating has a slip angle which is greater than a slip angle
of a lubricious coating having an amount of lubricious material which is about
5% to about 100% of the first amount. Surprisingly, a lubricious coating having
about 5% to about 10% of the first amount of lubricious material had a slip angle
about equal to the slip angle of the first lubricious coating, and thus was not
significantly less lubricious than the first lubricious coating. For example, a
3.0 mm outer diameter balloon coated with a lubricious coating having about 5%
of the first amount of lubricious material (i.e., coated with a solution of about
5 wt % of the first lubricious coating
40 solution) had a slip angle of
about 6 to about 9 degrees, compared to a slip angle of about 4 to about 7 degrees
for a similar 3.0 mm outer diameter balloon coated with the first lubricious coating
40.
While illustrated on the entire outer surface of the balloon
24, the
second lubricious coating
41 may alternatively be on less than the entire
outer surface of the balloon. Similarly, none or only part of the exposed outer
surface of the tip
27 may be coated with the second lubricious coating
41,
and may alternatively be coated in whole or in part with the first lubricious coating
40 or a different coating. In FIG. 1, the first lubricious coating
40
is on the entire exposed outer surface of the outer tubular member
14 (i.e.,
from the end of the adapter/strain relief member at the proximal end of the catheter,
to the proximal shaft section
25 of the balloon
24). However, the
first lubricious coating
40 may be on only part of the exposed outer surface
of the outer tubular member, and is preferably on at least a distal section of
the exposed outer surface of the outer tubular member (e.g., a distal section equal
to about 18 to about 22% of the length of the outer tubular member
14).
In a presently preferred embodiment, the proximal end of the coating
40
on the shaft is located distal to the proximal adapter
28. In the embodiment
in which the balloon catheter is a rapid exchange type catheter having a guidewire
proximal port located distal to the proximal end of the catheter, the first lubricious
coating preferably extends along at least the exposed outer surface of the shaft
distal to the guidewire proximal port, although it may alternatively also extend
along the exposed outer surface of the tubular member forming the proximal shaft
section proximal to the guidewire proximal port.
Although the coatings
40,
41 are illustrated with aligned
ends at the proximal end of the balloon in the embodiment of FIG. 1 (i.e., the
distal end of the coating
40 is at the proximal end of the coating
41),
so that the coatings may abut one another, it should be understood that the coatings
may alternatively overlap one another. For example, the first coating
40
may extend in part onto an outer surface of the balloon, or the second coating
41 may extend in part onto an outer surface of the outer tubular member,
due to the manufacturing tolerances of the coating procedure. Thus, in one embodiment
(not shown) a distal portion of the first coating
40 extends along at least
a proximal section of the balloon and is subsequently covered by a proximal portion
of the second coating
41, so that the proximal portion of the second coating
41 overlaps the distal portion of the first coating
40. However,
in a presently preferred embodiment, the interface between the exposed outer surface
of the first coating
40 and the exposed outer surface of the second coating
41 is located at (i.e., radially aligned with) the proximal end of the balloon,
irrespective of whether the coatings are in an abutting or overlapping relation.
Alternatively, the interface between the exposed outer surface of the first coating
40 and the exposed outer surface of the second coating
41 may be
proximal or distal to the proximal end of the balloon.
In a method of dilating the stenosed section
31, the balloon catheter
10
is advanced within the blood vessel
30 to position the balloon
24
at a desired position at the stenosed section
31. The balloon
24
is inflated so that the balloon working length contacts and dilates the stenosed
section
31 of the blood vessel
30. FIG. 4 illustrates the inflated
balloon in contact with and dilating the stenosed section
31. The inflated
balloon in contact with the blood vessel/lesion preferably does not longitudinally
slip, or at least has an insubstantial amount of slippage proximally or distally
from the desired position at the stenosed section
31 during the dilatation.
After the balloon is inflated one or more times to dilate the stenosed section
31 as is conventionally known, and the balloon is deflated a final time,
to allow for repositioning or withdrawing the balloon catheter from the blood vessel.
The lubricious coatings
40 and
41 remain on the catheter outer surface
to facilitate removal or repositioning of the balloon catheter in the blood vessel.
To the extent not previously discussed herein, the various catheter components
may be formed and joined by conventional materials and methods. For example, the
outer and inner tubular members
14,
16 can be formed by conventional
techniques, such as by extruding and necking materials found useful in intravascular
catheters such a polyethylene, polyvinyl chloride, polyesters, polyamides, polyimides,
polyurethanes, and composite materials. The length of the balloon catheter
10
is generally about 108 to about 200 centimeters, preferably about 137 to about
145 centimeters, and typically about 140 centimeters for PTCA. The outer tubular
member
14 has an outer diameter (OD) of about 0.017 to about 0.036 inch
(0.43-0.91 mm), and an inner diameter (ID) of about 0.012 to about 0.035 inch (0.30-0.89
mm). The inner tubular member
14 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
24 is has a length of about 14 mm to about 46 mm, typically about 8 mm to
about 40 mm, an inflated working diameter of about 1.5 mm to about 5.0 mm.
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 form the scope of the invention. For example, although
the embodiment illustrated in FIG. 1 has an outer and inner tubular member defining
the inflation and guidewire lumens, respectively, the shaft may alternatively comprise
a dual-lumen design as is conventionally known. 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.
*
