Note: Descriptions are shown in the official language in which they were submitted.
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CATHETER SHAFT WITH AN OBLONG TRANSVERSE CROSS-SECTION
BACKGROUND OF THE INVENTION
This invention generally relates to intravascular catheters,
such as balloon dilatation catheters used in percutaneous transluminal
coronary angioplasty (PTCA).
PTCA is a widely used procedure for the treatment of
coronary heart disease wherein a balloon dilatation catheter is advanced
into the patient's coronary artery and the balloon on the distal portion of
the catheter is inflated within the stenotic region of the patient's artery to
open up the arterial passageway and thereby increase the blood flow
therethrough. To facilitate the advancement of the dilatation catheter into
the patient's coronary artery, a guiding catheter having a preshaped distal
tip is first percutaneously introduced into the cardiovascular system of a
patient by the Seldinger technique through the brachial or femoral arteries
and is 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 its
proximal end, which extends out of the patient, to guide the distal tip of
the guiding catheter into the desired ostium. A balloon dilatation catheter
may then be advanced through the inner lumen of the guiding catheter
into the patient's coronary artery until the balloon on the dilatation
catheter is disposed within the stenotic region of the patient's artery.
The balloon'is inflated and deflated one or more times to open up the
arterial passageway and increase the flow of blood.
One type of catheter frequently used in PTCA procedures is
an over-the-wire type balloon di!atation catheter. Commercially available
over-the-wire type dilatation catheters include the SIMPSON ULTRA LOW
PROFILE (TM), the HARTZLER ACX (R), the HARTZLER ACX II (TM), the
PINKERTON .018 (TM) and the ACS TEN (TM) balloon dilatation catheters
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sold by the assignee of the present invention, Advanced Cardiovascular
Systems, Inc. (ACS).
Another type of over-the-wire dilatation catheter is the rapid
exchange type catheter, which was introduced by ACS under the
trademark ACS RX Coronary Dilatation Catheter. It is described and
claimed in U.S. Patent No. 5,040,548 (Yock), U.S. Patent No. 5,061,273
(Yock), U.S. Patent No. 4,748,982 (Horzewski et al.) and U.S. Patent No.
5,154,725 (Leopold),, This
dilatation catheter has a short guidewire receiving sleeve or inner lumen
extending through a distal portion of the catheter. The sleeve or inner
lumen extends proximally 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 member of the catheter. A slit may be provided in the
wall of the catheter body which extends distally from the second
guidewire port, preferably to a location proximal to the proximal end of
the inflatable balloon. The structure of the catheter allows for the rapid
exchange of the catheter without the need for an exchange wire or
adding a guidewire extension to the proximal end of the guidewire.
Some over-the-wire and rapid exchange type dilatation
catheters have perfusion capabilities where one or more perfusion ports
are provided in the catheter shaft proximal to the dilatation balloon which
are in fluid communication with a guidewire receiving inner lumen
extending to the distal end of the catheter. Additionally, one or more
perfusion ports are preferably provided in the catheter shaft, distal to the
balloon which are also in fluid communication with the guidewire
receiving inner lumen. When the balloon of a dilatation catheter with
perfusion capabilities is inflated to dilate a stenosis, oxygenated blood in
the artery or the aorta or both, depending upon the location of the
proximal perfusion parts of the dilatation catheter within the coronary
anatomy, is forced to pass through the proximal perfusion ports, through
the guidewire receiving inner lumen of the catheter and out the distal
perfusion ports. The flow of oxygenated blood downstream from the
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inflated balloon minimizes ischemic conditions in tissue distal to the
balloon and allows for long term dilatations, e.g. 30 minutes or even
several hours or more. Commercially available perfusion type dilatation
= catheters include the STACK PERFUSION (TM) and the ACS RX
PERFUSION (TM) dilatation catheters which are sold by ACS.
A continual effort has been made in the development of
intravascular catheters, particularly angioplasty catheters, to reduce the
transverse dimensions or profile of such catheters and the flexibility
without detrimentally affecting the pushability and other characteristics of
the catheters, particularly in the distal portion of the catheters which are
advanced through tortuous anatomy. A balloon dilatation catheter with
an increased flexibility and an increased pushability allow the catheter to
be advanced much further into a patient's vasculature and to cross much
tighter lesions.
Despite the many technical advances in these areas, the
need for intravascular catheters having even greater flexibility and
pushability remains. The present invention satisfies these and other
needs.
SUMMARY OF THE INVENTION
The present invention is directed to an elongated
intravascular catheter with improved flexibility and pushability, particularly
in the distal portion thereof.
The catheter shaft of the invention has, at least-in the distal
portion thereof, an oblong transverse cross-section wherein the
transverse dimension in a first direction is larger than the transverse
dimension in a second direction perpendicular to the first direction. In a
presently preferred embodiment the larger transverse dimension is about
1.1 to about 3 times, preferably about 1.2 to about 2.5 times, greater
than the smaller perpendicular transverse dimension. For dilatation
catheters suitable for coronary arteries the differential between the first
and second transverse dimensions is at least about 0.003 inch (0.076
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mm) and for dilatation catheters for peripheral use this differential should
be at least about 0.005 inch (0.127 mm). The shape of the oblong
transverse cross-section proximal to the balloon is preferably oviform or
elliptical in nature. The length of the oblong portion of the catheter shaft
is at least about 4 cm., preferably at least about 7 cm. The entire length
of the catheter shaft may have the desired oblong transverse cross-
section =
or only the portion of the catheter which extends out of the
guiding catheter, e.g. about 10 to about 40 cm. Advantages have also
been recognized with the proximal portion of the catheter shaft having an
oblong transverse cross-section in accordance with this invention.
In one embodiment the intravascular catheter of the
invention generally includes, at least in the distal portion thereof, an inner
tubular member having an inner lumen extending therein and an outer
tubular member disposed about the inner tubular member with at least
about 30% and not more than about 90%, preferably not more than
about 80%, of the inner periphery of the outer tubular member taking the
shape of and being secured to exterior of the inner tubular member along
a length of the catheter shaft of at least about 4 cm, preferably at least
about 7 cm. An inner inflation lumen extends along the secured length
between the portion of the outer tubular member which does not take the
shape of and which is not secured to the underlying inner tubular
member. The bond between the secured inner and outer tubular member
need not be continuous. It may be intermittent, so long as a significant
portion of the interface between the two members is secured along the
length. The inner and outer tubular members may be secured together by
heat or laser bonding, adhesive bonding, heat shrinking the outer tube
onto the inner tube or other suitable means.
By securing a length of the outer tubular member in the distal
portion of the catheter to the exterior of the inner member, the profile of
the catheter body in at least one transverse dimension in that area is
reduced substantially to thereby provide improved flexibility. Moreover, =
the secured portions of the inner tubular member and the outer tubular
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member support one another thereby providing improved pushability.
Substantial reductions in only one transverse dimension can provide
substantial improvements in flexibility. Minimum cross-sectional
dimensions of the small diameter section of the outer tubular member for
coronary dilatation catheters are on the order of about 0.01 to about 0.06
inch (0.51 - 1.5 mm). For peripheral arteries this dimension may be iarger.
The improvements of the invention are applicable to a wide
range of elongated intravascular catheters which are at least 90 cm in
length and which are percutaneously introduced and advanced deep
within the patient's vascular system, such as in the coronary anatomy. It
is particularly suitable in essentially all types of dilatation catheters with
inflatable or expandable dilatation members on their distal extremities,
such as those described in the patents incorporated herein by reference.
These and other advantages of the invention will become more apparent
from the following detailed description of the invention when taken in
conjunction with 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.
Fig. 4 is a transverse cross-sectional view of the catheter
shown in Fig. 1 taken along the lines 4-4.
Fig. 5 is a transverse cross-sectional view of the catheter
shown in Fig. 1 taken along the lines 5-5.
Fig. 6 is an elevational view, partially in section, of another
dilatation catheter embodying features of the invention.
Fig. 7 is a transverse cross-sectional view of the catheter
shown in Fig. 6 taken along the lines 7-7.
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Fig. 8 is a transverse cross4 ;.sectional view of the catheter
shown in Fig. 6 taken along the lines 8-8.
Fig. 9 is a transverse cross-sectional view of the catheter
shown in Fig. 6 taken along the lines 9-9. 5 Fig. 10 is a transverse cross-
sectional view of the catheter
shown in Fig. 6 taken along the lines 10-10.
Fig. 11 is an elevational view, partially in section, of another
dilatation catheter embodying features of the invention.
Fig. 12 is a transverse cross-sectional view of the catheter
shown in Fig. 11 taken along the lines 12-12.
Fig. 13 is a transverse cross-sectional view of the catheter
shown in Fig. 11 taken along the lines 13-13.
Fig. 14 is a transverse cross-sectionai view of the catheter
shown in Fig. 11 taken along the lines 14-14.
Fig. 15 is a transverse cross-sectional view of the catheter
shown in Fig. 11 taken along the lines 15-15.
Fig. 16 is an elevational view, partially in section, of an
alternative embodiment of the invention wherein a supporting tube is
provided between the unsecured portion of the outer tubular member and
the inner tubular member.
Fig. 17 is a cross-sectional view of the catheter shown in
Fig. 16 taken along the lines 17-17.
Fig. 18 is a cross-sectional view of a catheter shaft of
another embodiment of invention wherein there are two unsecured
= lengths of the outer tubular which define lumens with the underlying inner
tubular member.
Fig. 19 is an elevational view, partially in section, of another
embodiment of the invention in which the catheter shaft proximal to the
balloon has the desired transverse cross-sectional dimensions and a
hypotube formed of pseudoelastic NiTi alloy supports the inflation lumen
to prevent kinking.
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Fig. 20 is a transverse cross-sectionai view of the
embodiment shown in Fig. 19 taken along the lines 20-20.
Fig. 21 is a partial elevationai view, particularly in section, of
a rapid exchange version of the catheter shaft shown in Figs. 19-20.
Fig. 22 is a elevational view, partially in section, of an
alternative embodiment of an over-the-wire dilatation catheter.
Fig. 23 is a transverse cross-sectional view of the
embodiment shown in Fig. 22 taken along the lines 23-23.
Fig. 24 is a transverse cross-sectional view of the
embodiment shown in Fig. 22 taken along the lines of 24-24.
DETAILED DESCRIPTION OF THE INVENTION
Figs. 1-5 schematically illustrate an over-the-wire dilatation
catheter 10 embodying features of the invention. The catheter 10
includes an elongated catheter shaft 11 which has an inner tubular
member 12, an.outer tubular member 13 disposed about the inner tubular
member and an adapter 14 secured to the proximal ends of the inner and
outer tubular members. A relatively inelastic, inflatable balloon 15 which
is integral with the outer tubular member 13 and a distal skirt 17 which is
secured to the distal end of the inner tubular member 12. Alternatively,
the balloon 15 may be formed from different material and be secured to
the outer tubular member 13.
As shown in Figs. 1 and 3, the distal portion of the outer
tubular member 13 in part takes the shape of and is secured to the
exterior of the inner tubular member 12 along the length 18. The
unsecured portion 20 of the outer tubular member 13 along the length 18
forms with the inner tubular member 12 an inflation lumen 21 which is in
fluid communication with the interior of the balloon 15. The inner lumen
22 of the inner tubular member 12 extends parallel to the inflation iumen
21 along the length 18. As best shown in Fig 3, the transverse
= dimension of the catheter shaft 11 along the length 18 in the vertical
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direction is substantially larger than the transverse dimension of the
catheter shaft in the horizontal direction along said length.
The proximal portion of the catheter shaft 11, as shown in
Figs: 1-3, is conventional where the outer tubular member 13 is disposed
about but is unsecured to the inner tubular member 12 and defines with
the inner tubular member an annular inflation lumen 23 wh:ch is in fluid
communication with the inflation lumen 21 in the distal portion of the
catheter shaft.
The use of the dilatation catheter shown in Figs. 1-5
generally may follow conventionai PTCA practices with over-the-wire type
dilatation catheters. A guidewire 24 is backloaded into the inner lumen
22 of the inner tubular member 12 and both the guidewire and the
catheter 10 are advanced together through a guiding catheter (not shown)
which has been previously disposed within the patient's arterial system,
with the distal end of the guiding catheter seated within the ostium of the
desired coronary artery. The guidewire 24 is advanced out the distal end
of the guiding catheter into the patient's coronary anatomy until it crosses
the lesion to be dilated, and then the dilatation catheter 10 is advanced
over the guidewire which is being held in position, until the balloon 15 on
the dilatation catheter is properly disposed within the stenotic region, so
that the lesion can be dilated upon one or more inflations of the balloon.
After the dilatation, the balloon 15 is deflated and the catheter 10 and the
guidewire 24 may be withdrawn from the patient. If further treatment or
diagnosis is to be conducted, the guidewire 24 can be replaced with an
exchange wire before removing the dilatation catheter so that the first
catheter can be removed and another advanced into the desired location
or an extension wire can be attached to the proximal end of the guidewire
in place which extends out of the patient to perform essentially the same
function. See the discussion of exchange wires and extension wires in
U.S. Patent 4,827,941 (Taylor et al. ),
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Figs. 6-10 schematically illustrate another dilatation catheter
30 embodying features of the invention which is configured for rapid
exchange. The structure of the most distal portion of the catheter shaft
31 is'quite similar to the embodiment shown in Figs. 1-5 in that the distal
section of the catheter shaft 31 includes an outer tubular member 32
which is disposed about an inner tubular member 33 and which in part
takes the shape of and is secured to the exterior of the inner tubuiar
member along a length 34 of the distal shaft. An unsecured portion 35 of
the outer tubular member 32 forms an inflation lumen 36 which is in fluid
communication with the relatively inelastic balloon 37. In this
embodiment, the outer tubular member 32 and the balloon 37 are formed
in a unitary construction. The distal skirt 38 of the balloon 37 is secured
to the distal end of the inner tubular member 33.
Guidewire receiving inner lumen 40 extends proximally
within the inner tubular member 33 from a distal guidewire port 41 in the
distal end of the inner tubular member to a proximal guidewire port 42. A
guidewire 43 is slidably disposed within the inner lumen 40 and extends
out both the distal port 41 and the proximal port 42. A slit 44 is provided
in the secured sections of the inner and outer tubular members 33 and 32
respectively and it extends distally from the proximal guidewire port 42 to
a location 45 proximal to the balloon 37 to facilitate separation of the
guidewire 43 and the catheter shaft 31 when replacing catheter 30 with
another catheter as described in U.S. Patent 4,748,982 (Horzewski et a/. ).
The proximal guidewire port
42 is located at ieast about 5 cm but not more than about 45 cm from
the distal end of the catheter.
The proximal portion of the catheter shaft 31 has a high
strength inner tubular member 46, e.g. hypotubing, with a tightly fitting
outer plastic jacket or coating 47. An adapter 48 is secured to the
proximal end of the catheter shaft 31 to direct inflation fluid -through the
inner lumen 50 in the high strength tubular member 46 and the inflation
lumen 36 between the inner tubular member 33 and the unsecured
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portion of the outer tubular member 32 to the interior of balloon 37. The
distal extremity 51 of the high strength tubular member 46 is tapered to
facilitate extension into the proximal end of the inflation lumen 36 where
it is secured by suitable means such as an adhesive or by heat shrinking
the proximal end of the outer tubular member about the tapered extremity
51. The high strength tubular member may be formed of stainless steel
or a NiTi alloy, particularly a NiTi alloy with pseudoelastic properties, such
as described in U.S. Patents 5,411,476 issued May 2, 1995; 5,341,818 issued
August 30, 1994; and 5,637,089 issued June 10, 1997, assigned to the
present assignee, Advanced Cardiovascular Systems, Inc.
A dual lumen type construction such as described in
Horzewski et al. above may also be used in the portion of the catheter
shaft 31 proximal to the proximal guidewire port 42.
There are at least two modes of inserting the dilatation
catheter 30 of this embodiment into the patient's coronary anatomy. The
first method is for the most part the same as in the prior embodiment,
namely, the guidewire 43 is preloaded into the short guidewire receiving
inner lumen 40 of the inner tubular member 33 and both are advanced
'through a guiding catheter (not shown) previously disposed within the
patient's arterial system with the distal end of the guiding catheter seated
within the ostium of a coronary artery. The second mode, frequently
called the "bare wire" technique, involves first advancing a guidewire 43
through and out the guiding catheter until the distal extremity of the
guidewire is positioned within the patient's coronary artery across the
lesion to be dilated. The proximal end of the guidewire 43, which is
outside the patient, is backloaded, i.e. inserted into the short inner lumen
40 of the inner tubular member 33 and advanced proximally therein until
it exits the guidewire port 42. The proximal end of the guidewire 43 is
held In place and the catheter 30 is advanced over the guidewire through
the patient's vascular system until the dilatation balloon 37 on the
catheter is positioned across the stenotic region. The stenosis is dilated
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upon the inflation of the balloon 37, and, after the dilataiion of the lesion,
the balloon is deflated and the catheter is removed from the patient's
artery. If other treatments are necessary, the catheter 30 is slidably
withdrawn over the guidewire 43, leaving the guidewire in place so that
other catheters can be advanced over the in-place guidewire in a similar
manner without the need for exchange wires or guidewire extensions,
thereby significantly reducing the overall time for the procedure.
Figs. 11 through 15 illustrate yet another dilatation catheter
60 embodying features of the invention which provides for the perfusion
of blood distal to the catheter during the dilatation of a stenotic lesion.
The catheter 60 includes the catheter shaft 61, an inner tubular member
62 which has an inner lumen 63, an outer tubular member 64 disposed
about the inner tubular member, an adapter 65 secured to the proximal
ends of the inner and outer members, and a relativeiy inelastic balloon 66
which is secured by its distal end to the distal end of the inner tubular
member 62. A portion of the outer tubular member 64 has a distal
section 67 a length 68 of which is secured to the exterior of the inner -
tubular member 62 as previously described in the first two embodiments
of the invention. The above-described portion of this embodiment has
essentially the same structure as the embodiments shown in Figs. 1-10.
The dilatation catheter shown in Figs. 11-15 differs from the
other embodiments in that it has a plurality of perfusion ports 69 proximal
to the balloon 66 which pass through the secured walls of the inner and
outer tubular members 62 and 64 respectively and which are in fluid
communication with the inner lumen 63 of the inner tubular member 62.
Additionafly, one or more perfusion ports 70 are provided distal to the
balloon 66 through the wall of the inner tubular member 62 and are in
fluid communication with the inner lumen 63 extending therein. In this
. manner, when the balloon 66 is inflated during an angioplasty procedure
within a patient's vasculature, oxygenated blood is forced to pass through
the proximal perfusion ports 69, through the inner lumen 62 and then out
the distal perfusion ports 70 to provide oxygenated blood distal to the
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catheter 60 and thereby avoid the generation of ischemic conditions in
downstream tissue. The transverse dimensions of the inner tubular
member 62 within the secured section are preferably larger than in the
embodiments previously discussed to allow for an increased flow of
blood.
The use of the embodiment shown in Figs. 11-15 is
essentially the same as the embodiment shown in Figs. 1-5. The only
essential difference is that the balloon 66 can be inflated for significantly
longer periods than the first described embodiments, e.g. typically about
20-30 minutes but possibly up to 5 hours or more, because oxygenated
blood is continuously flowing to the tissue distal to the inflated balloon.
The dilatation catheter 30 shown in Figs. 6-10 may be
modified by providing a plurality of perfusion ports in the catheter shaft as
shown in Figs. 11-15 distal to the proximal guidewire port 42. = However,
the guidewire port 42 is preferably spaced sufficiently far proximally from
the portion of the secured distal section having the perfusion ports so that
the guidewire 43 can be pulled proximally and remain within the inner
lumen 40 of the inner tubular member 33 while the balloon is inflated
during a long term dilatation but not interfere with the flow of blood
through the perfusion ports. After the angioplasty procedure is
completed, the guidewire 43 can then be advanced distally through the
inner lumen 40 and out the distal end thereof in order to maintain access
to the lesion in case further treatment or diagnosis is necessary or
desirable.
- The above describod catheters may be made by conventional
techniques well known to those skilled in the art. Many suitable
techniques are described in the references referred to herein. The small
diameter distal sections may be formed by heat shrinking the portion of
the outer tubular members which form the distal sections onto the
underlying inner tubular members with a mandrel disposed in the space
between the inner and outer tubular members so that upon the heat
shrinking of the outer tubular member an inflation lumen is formed
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through the distal sections which is in fluid communication with the
lumen in the proximal portion of the catheter body and the interior of the
balloon. This bonds the small dimensioned distal section to the inner
tubular member. A mandrel may also be inserted into the inner lumen of
the inner tubular member to support the latter during the heat shrinking of
the outer tubular member thereon to maintain its circularity. Alternate
methods may be employed to make the small dimensioned distal section.
For example, the small dimensioned distal section 17 may be preformed
and then be adhesively bonded to the exterior of the inner tubular
member. Multiple lumens similar to the inflation lumen may be formed in
the small dimensioned section, such as the top and bottom thereof, by
employing multiple mandrels when heat shrinking the outer tubular
member onto the exterior of the inner tubular member.
With the embodiment of the invention shown in Figs. 6-10
which have a slit 45 extending from the proximal guidewire port 42
through the secured portion of the catheter shaft 31 to facilitate the
separation of the catheter and the guidewire, there is a tendency for the
slit to open up when the fluid pressure within the inflation lumen 36 is
raised to high levels to inflate the balloon 37 for dilatation of stenoses.
The opening of the slit allows the guidewire to extend through the
expanded or opened slit 44, but upon deflation of the balloon the slit
closes onto the guidewire 43 which precludes independent movement of
the guidewire and catheter. To avoid this problem, it is preferred to
provide a support tube 71 to define the inner lumen 36 as shown in Figs.
16 and 17 and to prevent the expansion of the unsecured portion of the
outer tubular member 32. A filler 72 may be provided to eliminate voids
between the support tube 71 and the unsecured portion of the outer
tubular member 32. The support tube 71 may be formed of polyimide or
, other high strength polymer materials or metals such as the previously
described pseudoelastic NiTi alloys. The catheter shown in Figs. 16 and
17 is, except for the support tube 71 and filler 72, essentially the same
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as the catheter shown in Figs. 6-10 and the corresponding parts are
numbered the same.
Fig. 18 is an alternative distal shaft construction wherein an
additional inner lumen 80 which can be used as an additional inflation
lumen to vent air or to deliver other fluids. In this embodiment the
additional lumen 80 should extend to the proximal end of the catheter shaft so
that fluid can be introduced into or withdrawn from the additional
lumen through an adapter mounted on the proximal end. For delivery or
withdrawal of inflation fluid the lumen 80 should terminate within the
interior of the inflatable dilatation member. The lumen 80 should extend
to the distal end of the catheter to deliver fluids distal to the catheter.
Figs. 19-20 illustrate an alternative embodiment of an over-
the-wire dilatation catheter 90 which has a flexible distal shaft section
91, a stiffer proximal shaft section 92, an inflation lumen 93 and a
15= guidewire receiving lumen 94. A dilation balloon 95 is mounted on the
distal shaft section 91 having an interior which is in fluid communication
with inflation lumen 93 through inflation port 96. The inflation lumen 93
extends from the adaptor 97 to the inflation port 96 through the proximal
and distal shaft sections 92 and 91. An inflation lumen 93 and a
guidewire receiving inner lumen 94 are stacked in the long direction of the
transverse cross-sectional profile as shown in Fig. 20. The proximal shaft
section 91 of the dilatation catheter 90 has a flexible hypotube 98 which
defines the inflation lumen 93 as shown in Fig. 20 to prevent the kinking
of the inflation lumen when the catheter is advanced through tortuous
passageways. The hypotube 98 is preferabiy formed of an alloy, such as
pseudoelastic NiTi alloy, having an austenite phase which is stable at
body temperature and exhibiting a stressed induced austenite -to-
martinsite phase transformation. The hypotube 98 extends at least the
length of the proximal section of the catheter to a location proximal to the
dilation balloon 95. Both proximal and distal shaft sections 92 and 91
have eliptical transverse cross-sections with the inflation lumen 93 and
the guidewire receiving lumen 94 being stacked in the long direction of
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the transverse cross-sectional profile. The embodiment shown in Figs.
19-20 depict an over-the-wire version of the catheter 90 with a guidewire
99 extending through the guidewire lumen 94 throughout its entire
length.
Fig. 21 illustrates a modification of the catheter 90 shown in
Figs. 19-20 which is provided with a proximal guidewire port 100 in
communication with the guidewire receiving lumen 94. A plug 101 may
be provided in the guidewire receiving lumen 94 to urge the proximal end
of guidewire 100 when the latter is advanced proximally through the
guidewire lumen 94. If desired, the guidewire lumen 94 and the adaptor
97 may be provided with a slit 102 such as described in U.S. Patent
4,748,982 (Horzewski) and U.S. Patent 5,135,535 (Kramer).
Another alternative embodiment of the invention is shown in
Figs. 22-24 wherein the dilatation catheter 110 has a catheter shaft 111
with a distal section 112 having an oblong transverse cross-sectional
shape and a proximal section 113 having an inner tubular member 114
and an outer tubular member 115. The distal end of the outer tubular
member 115 is secured about the exterior of the proximal end of the
distal section 112 and the distal end of the inner tubular member 114 is
secured to a cylindrical extension 116 of the distal shaft section 112. The
distal shaft section 112 preferably tapers to smaller dimensions at
location 117 to increase the flexibility of the distal most portion of the
catheter shaft. A guidewire receiving inner lumen 118 extends within the
inner tubular member 114. from the central arm 119 of the adapter 120
on the proxiinal end of the catheter shaft 111 through the distal section
112 to a guidewire port 121 in the distal end of the shaft. An inflation
lumen 122 extends from the second arm 123 of adapter 120 through the
annutar space between the inner and outer tubular members 114 and
115, through the distal shaft section 112 into the interior of the inflatable
member 124.
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The various components of the catheters and guidewires of
the invention can be formed from a wide variety of conventional
materials. The catheter shaft, including the inner and outer tubular
members may be made from polymeric materials such as polyethylene,
polyamide, polyvinyl chloride, polyester (e.g. Hytrel which is available
from DuPont), poiyetheretherketone (e.g. Grade 381G from Victrex
U.S.A.) and other suitable polymeric materials. The hypotubing may be
formed of stainless steel or NiTi superelastic alloy material, such as
described previously. The balloon may be made from polyethyiene,
polyethylene terephthalate and other relatively inelastic polymers and
other materials.
The dimensions of the catheters generally follow the
dimensions of conventional intravascular catheters. For coronary use the
length is typically about 135 cm and the maximum outer diameter of the
outer tubular member is about 0.02 to about 0.06 inch (0.51-1.52 mm).
The transverse shape of the proximal section of the catheter shaft may be
circular, oviform or elliptical.
While the invention has been described herein primarily in
terms of certain preferred embodiments, the invention may be employed
in a wide variety of embodiments. Additionally, modifications and
improvements can be made to the invention without departing from the
scope thereof. Although individual features of embodiments of the
invention may be shown in some of the drawings and not in others, those
skilled in the art will recognize that individual features of one embodiment
of the invention can be combined with any or all the features of another
embodiment.
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