Note: Descriptions are shown in the official language in which they were submitted.
_ WO 96/031~i3
-- 2~ 95948
CCM. 051l~ POLYESTER MATERIAL HAVING A LUBRICOUS SURFACE
RELATED APPLICATIONS
This application is a continuation-in-part ap~ ' -n of
appi,~dLion Serial No. 08/134,863, filed on October 12, 1993, entieled
COMPOSITE MATERIAL HAVING A LUBRICOUS SURFACE FOR
CATHETER USE, which is a continuation of application Serial No.
07/833,369, filed on February 10, 1992, entitled COMPOSiTE MATERIAL
HAVING A LUBRICOUS SURFACE FOR CATHETER USE.
BACKGROUND OF THE INVENTION
This invention yenerally relates to intraluminal catheters,
such as guiding catheters and balloon dilatation catheters used in
percutaneous transiuminal coronary a~yiupla:.Ly (PTCA).
In classic PTCA procedures, a guiding catheter having a
preshaped distal tip is percutaneously introduced by a Seldinger technique
into the cardiovascular system of a patient and advanced therein until the
preshaped distal tip of the guiding catheter is disposed within the aorta
adjacent the ostium of the desired coronary artery. The guiding catheter
is twisted or torqued from the proximal end to turn the distal tip of the
guiding catheter so that it can be guided into the desired coronary ostium.
In over-the-wire systems, a guidewire and a balloon dilatation catheter are
introduced into and advanced through the guiding catheter to the distal
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tip thereof, with the guldewire slidably disposed within an inner lumen of
the dilatation catheter. The guidewire is first advanced out the distal tip
of the guiding catheter, which is seated in the ostium of the patient's
coronary artery, urmil the distal end of the guidewire crosses the lesion to
be dilated. The dilstation catheter is then advanced out of the distal tip
of the guiding catheter, over the previously advanced guidewire, until the
balloon on the distal extremity of the dilatation catheter is properly
positioned across the lesion. Once properly posiLioned, the balloon is
inflated to a predetermined size with radiopaque liquid at relatively high
pressures (e.g., generally 4-12 dl"~osphel~s~ to dilate the stenosed region
of the diseased artery. One or more inflations may be necessary to
effectively dilate the stenosis. Additional stenoses may be dilatated with
the same catheter. When the dila~d~ions are co."plel~d, the balloon is
deflated so that the dilatation catheter can be removed from the dilated
stenosis and blood flow will resume through the dilated artery.
Further details of guiding catheters, dilatation catheters,
guidewires, and other devices for angioplasty procedures can be found in
U.S. Patent 4,323,071 (Simpson-Robert); U.S. Patent 4,439,185
(Lundquistl; U.S. Patent 4,468,224 ~Enzmann etal.); U.S. Patent
4,516,972 (Samson); U.S. Patent 4,438,622 (Samson et al.~; U.S.
Patent 4,554,929 (Samson et al.); U.S. Patent 4,582,185 ISamson);
U.S. Patent 4,616,652 (Simpson); U.S. Patent 4,638,805 (Powell); U.S.
Patent 4,748,986 (Morrison et al.); U.S. Patent 4,898,577 (8adger et
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al.); and U.S.Patent 4,827,943 ~Taylor et a/.) which are inco"uo,dlcd
herein in their entirety by reference thereto.
Fixed-wire dilatation catheters for coronary angioplasty,
which were first described in U. S. Patent 4,252,181 (Samson) now
~ 5 Reissue patent 33,166, are similarly used except there is no longitudinal
movement between the guidewire and the catheter. The fixed-wire
dilatation catheters generally have an outer tubular member with an
inflatable balloon on the distal section thereof which is capable of dilating
a stenosis, and a guiding member extending out through the distal end of
the balloon which aids in advancing the catheter to a desired location
within the patient's vasculature. They also usually have no inner tubular
member and therefore have lower profiles, e.g. transverse dilllensiol,s,
than over-the-wire dilatation catheters having the same inflated balloon
size. Moreover, because the fixed-wire catheters have the guidewire or
guiding member fixed or at least restricted as to longitudinal movement,
these catheters generally have greater pushability than over-the-wire type
catheters such as described and claimed in U.S. Patent 4,323,071
~Simpson-Robert). The lower profile and greater pushabiiity of the fixed-
wire dilatation catheters allows them to cross tighter lesions and to be
advanced much deeper into a patient's coronary anatomy than the over-
the-wire dilatation catheters of ~:olllpdldble sizes.
Various improvements have been made to intravascular
catheters used in angioplasty and other intravascular procedures. Of
particular note is a rapid exchange type catheters described and claimed
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in U.S. Patsnt 5,040,548 (Yockh U.S. Patent 5,061,273 ~Yock), and
U.S. Patent 4,748,982 jHor2ewski et a/,), which are inco-,uo,dlt,d herein
in their entirety by reference. The rapid exchange type dilatation catheter
has a short guidewire receiving sleeve or inner lumen extending through
the flexible distal portion of the catheter which extends out of the guiding
catheter into the patient's coronary artery during the angioplasty
procedure. The slecve extends proximally a distance of at lesst 10 cm
and usually not more than about 50 cm from a first guidewire port in the
distal end of the catheter to a second guidewire port in the catheter
spaced proximally from the inflatable balloon of the catheter. A slit, as
described in l l~ .sld er al., is preferably provided in the catheter wall
which extends distally from the second guidewire port, preferably to a
location proximal to the proximal end of the inflatable balloon to aid in the
removal of the catheter from a guidewire. The structure of the catheter
allows for the rapid exchange of the catheter without the need for the use
of an exchange wire or adding a guidewire extension to the proximal end
of the guidewire. The design of this catheter has been widely praised by
the medical ,UlU~ >iUn and has met with much co~ ,idl success in the
market place because of its unique design.
A substantial improvement in the rapid exchange type
dilatation catheters, such as described above, has recently been made by
Mclnnes et a/. which is described in copending applications Serial No.
07/476,056, filed February 7, 1990 and Serial No. 07/541,264 filed
June 19, 1990, both entitled READILY EXCHANGEABLE PERFUSION
2 1 9 5 4 8
W096103163 ~; r r~~
DILATATION CATHETER, and which are incorporated herein by reference.
In these rapid exchange type dilatation catheters, perfusion ports are
provided in the catheter shaft, proximal and distal to the balloon, which
are in fluid communication with the guidewire receiving inner lumen to
allow blood to perfuse distal to the catheter when the balloon is inflated.
Lubricous coatings have been applied to the surfaces of
guiding catheters, dilatation catheters and other intraluminal catheters in
order to reduce the friction between the surfaces of these catheters and
other components of the catheter systems in which the catheters are
employed during the intravascular procedures. For example, fluoropolymer
linings such as Teflon~ are very frequently employed as the inner linings
of guiding catheters in order to reduce the friction between the inner
lining of the guiding catheter and the guidewire and the catheters which
might be advanced through the inner lumen of the guiding catheter.
Lubricous silicone coatings have been applied to the surfaces of
guidewires and of dilatation catheters to likewise reduce the frictional
cha~d.,L~ri:,Lics of these devices. However, the application of these
lubricous coatings and linings are for the most part co",, I Led
manufacturing processes. Moreover, very frequently these coatings and
linings are not very durable and lose substantial portions of their lubricity
during the intraluminal or intravascular procedure.
What has been needed and heretofore unavailable is a
durable high strength plastic surface having long lasting lubricity which
does not require complicated manufacturing procedures. The present
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invention satisfies this and other needs.
SUMMARY OF THE INVENTION
The present invention is directed to an improved co"",o5ile
plastic material having a very durable lubricous surface and particularly to
tubular products for intraluminal catheter procedures within a human
patient made from such composite materials.
The materiai of the invention gencraily includes a
10 biocompatible polymer matrix having finely divided lubricous particulate
matter incorporated within the matrix.
The polymer matrix can be formed of thermoplastic
materials particularly Ll,e""opla5lic polyesters are preferred when the
final product has a tubular shape because thermoplastic polyesters can be
easily extruded or otherwise forrned in a conventional fashion and can be
more readily joined to other cc,mpu,le~"5. When the lubricous particulatc
is well dispersed within the polymer matrix prior to or during the extrusion
or other melt processing, the extrusion pressure or other forces needed to
form the product are significantly lowered and there is much better
20 di",el,sior,al control durin~ the extrusion process than the 5same plastic
materials without the lubricous particulate matter incorporated therein.
Increased strengths in addition to de~,~ased frictional characteristics are
also obtained by the incorporation of the lubricous particulate. The
coefficient of friction of this material ranges from about 0.03 to about
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0.20.
The tubular products of the invention can be formed into the
shafts for intraluminal catheters such as balloon dilatation catheters for
dngiopla: ~y procedures in a conventional manner.
The presently preferred polyester matrix is a polyester sold
under the tladealdlk HYTRELCD by DuPont particularly grades 7246 and
8238. HYTREL is believed to be a copolymer of pledollli~lallLly
polybutylene terephthalate and a lesser amount of pol~ Lldlll~Lllylene
ether glycol esterified with dimethyl terephthalate. Other minor
cur,~uonenL~ may be included.
These and other advantages of the invention will become
more apparent from the following detailed description of the invention
when taken in conjunction with the accompanying exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an elevational view partially in section of a balloon
dilatation catheter embodying features of the invention.
Fig. 2 is a transverse cross-sectional view of the catheter
shown in Fig. 1 taken along the lines 2-2.
Fig. 3 is a transverse cross-sectional view of the catheter
shown in Fig. 1 taken along the lines 3-3.
DETAILED DESCRIPTION OF THE INVENTION
Figs. 1-3 illustrate a balloon dilatation catheter which
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embodies features of the invention. The dilatation catheter generally
includes an outer tubular member 10, a dilatation balloon 11 on the distal
portion of the outer tubular member, an inner member 12 disposed within
the outer tubular member and the balloon and a multi-arm adapter 13
mounted on the proximal ends of the inner and outer tubular members.
The distal end of the balloon 11 i5 sealed about the distal end of the inner
tubular member 12 so that injection of inflation fluid under siy,lirica"L
pressure through annular lumen 14 to the interior of the balloon will result
in the inflation thereof. A guidewire 15 is slidably disposed within the
inner lumen 16 of the inner tubular member 12. The distal end of the
catheter is provided with a self venting means such as described in U.S.
Patent 4,638,r~05 ~Powell).
A radiopaque marker 17 is disposed about the inner tubular
member 12 at the mid-point of the balloon 11 to facilitate the
fluuroscopiG observation thereof during an angioplasty procedure. The
brachial marker 20 and femoral marker 21 are provided on the proximal
end of the inner tubular member 12.
In a~,o,da"ce with the invention, the inner tubular member
12 is formed of ~iUlllpOSi~ material which generally includes a polymer
matrix, preferably a readily extrudable thermoplastic pol,vester and
incorporaterd within the polyester matrix is a finely divided lubricous
particulate matter which range on the average from about 0.1 to about
100 microns, preferably about 0.5 to about 20 microns, in maximum
dimensions. The amount of particulate matter in the polymer matrix
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thereof may range from about 0.5 to about 50%, p~ ldLIy about 2 to
about 20%, of the precured mixture thereof. As used herein all
percentages are weight percent unless noted otherwise. Up to about 1%
of a dispersing agent, such as lecithin, silicone oil, veyetable oil,
polyethylene wax or mixtures thereof, may be incorporated into the
mixture to facilitate effective mixing of the particulate within the polymer
resin. However, with HYTREL it has been found that the graphite
particles can be fed into the extruder along with the HYTREL to provide
effective dispersing.
Particularly suitable lubricous particulate materials include
graphite, fluoropolymers such as Teflon~3, molybdenum disulfide, titanium
carbide, molybdenum carbide, graphite difluoride or mixtures thereof.
Presently preferred lubricous particulate include Micro 850 and Micro 250
graphite available from the Asbury Graphite Mills, located in Asbury
County, New Jersey. This graphite has an average maximum particle si~e
from about 3 to about 10 microns in maximum d;"~en~io,1. In addition,
silicone oils such as dimethylsiloxane polymers with a viscosity between
about 300 and 100,000 centipoise, preferably about 1000 to about
30,000 centipoise, can be incorporated along with the solid lubricous
particulate in amounts of up to 10%, preferably about 0.5 to about 4~~0.
Formation of the products of the invention typically involve
intimately mixing the lubricous particulate into the uncured or partially
cured polymer resin which forms the matrix of the cured product. If
needed, a dispersant may be first mixed with the lubricous particulate to
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facilitate a more uniform ~i;;,p~ "e"~ of the particulate throughout the
uncured resin. The dispersant may be advantageously added to the
lubricous particulate as a solution of isopropyl alcohol or other suitable
solvent to facilitate the incorporation thereof. The finely divided lubricous
particulate has a tendency to agglomerate and an intimate and uniform
mixture of the particulate within the polymer matrix can be very difficult
to obtain without a dispersant.
The polymer-particulate mixture is then preferably extruded
in a conventional manner into a tubuiar product having the desired
dimensions. After extruding, the tubular product is then cured.
To illustrate a presently preferred embodiment, a mixture
was prepared containing 96% of HYTREL ~&rade 7246~ and 496 graphite
powder and extruded into peliets. The peliets are extruded into a tubular
product. The tubular member is then cut to length and used in the
manufacture of a prototype dilatation catheter as shown in Figs. 1-3. The
tubular member will have a low coefficient of friction.
Whiie the invention has been described herein primarily in
terms of an inner tubular member for an o~fer-the-wire type dilatation
catheter of concentric design, the composite material of the invention can
be utilized in a wide variety intraluminal catheter components. For
example, the material can be used to form the outer tubular member in an
over-the-wire dilatation catheter or a fixed-wire dilatation catheter. All or
a portion of the outer tubular member may be formed of the polymer
~ WO ~6/03163 i , ~ 2 19 ~ ~ 4 8 r~"~s ~ ~
matrix-finely divided iubricous particulate. The material can also be used
to form the inflatable member or balloon of a dilatation catheter.
Guidewire receiving inner tubular members such as described in the Yock
and Horzewski et al. patents, which have been incorporated herein, may
be made of the col"~,osil~ material formed of polymer and low friction
particulate. Another use is the formation of guiding catheters in which the
colllposiLe material is used to form at least the inner liner of the catheter
to provide the lubricous inner lumen required in this type of intravascular
catheter. Other uses include shafts and inflatable members of urethral
dilatation catheters and Foley type catheters.
While the invention is described herein in terms of certain
presently preferred e~bodi"le"L~, those skilled in the art will recognize
that various changes and improvements can be made to the present
invention without departin~q from the scope thereof.
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