Note: Descriptions are shown in the official language in which they were submitted.
CA 02197461 2000-06-05
STENT DELIVERY SYSTEM
This invention is directed to a catheter that utilizes a balloon to dilate
structures or stenoses within the human body. More particularly, this
invention is
directed to a dilatation catheter having an eccentrically positioned balloon.
The use of balloon catheters to treat strictures, stenoses, or narrowings
within various parts of the human body is well known and is the subject of
many
patents. For example, Gruntzig, U.S. Patent No. 4,195,637, Simpson and Robert,
U.S. Patent No. 4,323,071, Bonzel, U.S. Patent No. 4,762,129, Yock, U.S.
Patents
Nos. 5,040,548 and 5,061,273, Frisbee and Samson, U.S. Patents Nos. 4,573,470
and 4,619,262, Chin et al., U.S. Patent No.4,493,711, Mueller et al., U.S.
Patent
No. 4,790,315, Walinsky, U.S. Patents Nos. 4,641,649 and 4,643,186, and
others,
teach that balloon catheters can be used to dilate stenoses in blood vessels.
In
each design, the balloon has a generally cylindrical shape, positioned in a
concentric manner in relation to the catheter shaft, and bonded distally
and/or
proximally to the shaft. When an operator attempts to pass a dilatation
balloon
having such a design through a very tight opening in a stenosis, the balloon
may
bunch up, i.e., fold up longitudinally like an accordion, as shown in Fig. 1,
and the
catheter will not pass through the stenosis. A balloon catheter in which the
20 balloon is bonded to the shaft for its entire length would eliminate this
problem.
Inflation of a concentrically mounted balloon results in a uniform force
circumferentially applied to the stenotic lesion. However, the structure or
morphology of the lesion is rarely uniform, and harder portions will require
more
force to dilate than will softer areas. This has necessitated the practice of
inflating
25 the balloon at very high pressures, causing overdistention, dissection, and
tearing.
In addition, at high pressures, a dilatation balloon may rupture, resulting in
serious
complications. Thus, there is a need for a balloon catheter which can apply a
focused, variable force for dilatation, at lower pressures.
In prior art dilatation balloon catheters, the shaft segment within the
30 balloon may be a solid wire (Frisbee and Samson), or it may be a hollow and
open-ended tube which allows the catheter to be moved over a guidewire
(Simpson/Robert, Bonzel, Yock). The catheter of Mueller et al., a
representative
structure of which is shown in Fig. 2, has small holes in the shaft proximal
to the
balloon to allow blood to enter, for the intended purpose of allowing blood to
CA 02197461 2000-06-05
2
perfuse the vessel while the balloon is inflated. Since the blood impacts the
balloon, turns to enter the small holes in the shaft, and then turns again to
exit the
catheter in the proximal direction, this design promotes turbulent blood flow
of
the type that often results in hemolysis and thrombosis. The balloon of
Walinsky
S is porous and is intended to deliver a therapeutic agent to the lesion while
the
balloon is inflated. Since the inflation pressure of the balloon is often high
to
effect dilatation, the drug may exit the pores in the balloon at a velocity
that would
injure or even perforate the vessel.
Thus, there is a need for a balloon dilatation catheter with a lumen
10 positioned external to the balloon, such that the lumen could be used for
therapeutic means (e.g., blood perfusion, drug delivery) during balloon
inflation.
In accordance with one aspect of the invention, there is provided in a
method for delivering a balloon-expandable stmt wherein the stmt in non-
expanded form is firmly positioned around the balloon on the distal portion of
a
15 balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a catheter shaft defining a first, inflation
lumen and a
20 second lumen, each of the first and second lumens having proximal and
distal
ends, and an inflatable dilatation balloon having proximal and distal ends,
wherein
the distal end of the first lumen opens into and is in fluid communication
with the
interior of the dilatation balloon and the second lumen extends longitudinally
with
the first lumen, the proximal end of the second lumen being adjacent to the
25 proximal end of the first lumen, the distal end of the second lumen being
open and
distal to the distal end of the first lumen, the section of the second lumen
distal to
the proximal end of the dilatation balloon being exterior to the dilatation
balloon,
the distal end of the second lumen being open and distal to the distal end of
the
dilatation balloon, and the second lumen being sufficiently linear to allow
the
30 catheter to be slidingly advanced over a guidewire.
In accordance with a further aspect of the invention, there is provided in a
method for delivering a balloon-expandable stmt wherein the stem in non-
expanded form is firmly positioned around the balloon on the distal portion of
a
balloon dilatation catheter, the distal portion of the catheter is inserted
CA 02197461 2000-06-05
3
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a catheter shaft defining a first, inflation
lumen and a
S second lumen, each of the first and second lumens having proximal and distal
ends, and an inflatable dilatation balloon having proximal and distal ends,
wherein
the distal end of the first lumen opens into and is in fluid communication
with the
interior of the dilatation balloon, the proximal end of the second lumen being
open
and being located substantially distal to the proximal end of the first lumen,
the
section of the second lumen distal to the proximal end of the dilatation
balloon
being exterior to the dilatation balloon, the distal end of the second lumen
being
open and distal to the distal end of the dilatation balloon, and the second
lumen
being sufficiently linear to allow the catheter to be slidingly advanced over
a
guidewire.
In accordance with an additional aspect of the invention, there is provided
in a method for delivering a balloon-expandable stmt wherein the stmt in non-
expanded form is firmly positioned around the balloon on the distal portion of
a
balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a first inflation lumen extending therethrough
and
having distal and proximal ends, the distal end of the first lumen opening
into and
being in fluid communication with the interior of an inflatable dilatation
balloon
25 having distal and proximal ends, and a second lumen extending coextensively
with the first lumen, having proximal and distal ends, wherein the proximal
end of
the second lumen is adjacent to the proximal end of the first lumen, the
distal end
of the second lumen is open and distal to the distal end of the balloon, and
wherein the distal section of the second lumen is exterior to the balloon and
has an
30 opening proximal, adjacent, or distal to the proximal end of the dilatation
balloon,
and the section of the second lumen distal to the opening is enlarged as
compared
to the proximal section of the second lumen.
In accordance with a yet further aspect of the invention, there is provided
in a method for delivering a balloon-expandable stmt wherein the stmt in non-
CA 02197461 2000-06-05
3a
expanded form is firmly positioned around the balloon on the distal portion of
a
balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
5 proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a catheter shaft defining a first, inflation
lumen and a
second lumen, each of the first and second lumens having proximal and distal
ends, and an inflatable dilatation balloon having proximal and distal ends,
wherein
the distal end of the first lumen opens into and is in fluid communication
with the
10 interior of the dilatation balloon and the second lumen extends
longitudinally with
the first lumen, the proximal end of the second lumen being adjacent to the
proximal end of the first lumen, the distal end of the second lumen being open
and
distal to the distal end of the first lumen, the section of the second lumen
distal to
the proximal end of the dilatation balloon being exterior to the dilatation
balloon
15 and containing a rigid or substantially rigid triangularly-shaped
lubricious liner,
the distal end of the second lumen being open and distal to the distal end of
the
dilatation balloon, and the second lumen being sufficiently linear to allow
the
catheter to be slidingly advanced over a guidewire.
In accordance with an additional aspect of the invention, there is provided
20 in a method for delivering a balloon-expandable stmt wherein the stmt in
non-
expanded form is firmly positioned around the balloon on the distal portion of
a
balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
25 proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a catheter shaft defining a first, inflation
lumen and a
second lumen, each of the first and second lumens having proximal and distal
ends, and an inflatable dilatation balloon having proximal and distal ends,
wherein
the distal end of the first lumen opens into and is in fluid communication
with the
30 interior of the dilatation balloon, the proximal end of the second lumen
being open
and being located substantially distal to the proximal end of the first lumen,
the
section of the second lumen distal to the proximal end of the dilatation
balloon
being exterior to the dilatation balloon and containing a rigid or
substantially rigid
triangularly shaped lubricious liner, the distal end of the second lumen being
open
CA 02197461 2000-06-05
3b
and distal to the distal end of the dilatation balloon, and the second lumen
being
sufficiently linear to allow the catheter to be slidingly advanced over a
guidewire.
In accordance with a yet further aspect of the invention, there is provided
in a method for delivering a balloon-expandable stmt wherein the stmt in non-
S expanded form is firmly positioned around the balloon on the distal portion
of a
balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a first, inflation lumen extending therethrough
and
having distal and proximal ends, the distal end of the first lumen opening
into and
being in fluid communication with the interior of an inflatable dilatation
balloon
having distal and proximal ends, and a second lumen extending coextensively
with the first lumen, having proximal and distal ends, wherein the proximal
end of
the second lumen is adjacent to the proximal end of the first lumen, the
distal end
of the second lumen is open and distal to the distal end of the balloon, and
wherein the distal section of the second lumen is exterior to the balloon and
has an
opening proximal, adjacent, or distal to the proximal end of the dilatation
balloon,
and the section of the second lumen distal to the opening is enlarged as
compared
to the proximal section of the second lumen and contains a rigid or
substantially
rigid triangularly shaped lubricious liner.
In accordance with an additional aspect of the invention, there is provided
in a method for delivering a balloon-expandable stmt wherein the stmt in non-
expanded form is firmly positioned around the balloon on the distal portion of
a
balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the stmt to expand, the balloon is deflated, and the catheter is removed
proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises a catheter shaft defining a first, inflation
lumen and a
second lumen, each of the first and second lumens having proximal and distal
open ends, an inflatable dilatation balloon having proximal and distal ends,
wherein the distal end of the first lumen opens into and is in fluid
communication
with the interior of the dilatation balloon, the distal end of the second
lumen being
distal to the distal end of the first lumen and the second lumen being
exterior to
CA 02197461 2000-06-05
3c
the dilatation balloon, the proximal and distal ends of the second lumen being
relatively disposed perfusion openings, and the second lumen permitting blood
flow past the dilatation balloon while the balloon is forcefully inflated with
pressurized fluid.
S In accordance with a yet further aspect of the invention, there is provided
in a method for delivering a balloon-expandable stmt wherein the stmt in non-
expanded form is firmly positioned around the balloon on the distal portion of
a
balloon dilatation catheter, the distal portion of the catheter is inserted
percutaneously into a patient's body to a desired site, the balloon is
inflated to
cause the steilt to expand, the balloon is deflated, and the catheter is
removed
proximally from the patient's body, the improvement wherein the balloon
dilatation catheter comprises: a catheter shaft defining a first inflation
lumen and
a second lumen, each of the first and second lumens having proximal and distal
ends, and an inflatable dilatation balloon having proximal and distal ends,
wherein
the distal end of the first lumen opens into and is in fluid communication
with the
interior of the dilatation balloon, and a portion of the second lumen extends
longitudinally with a portion of the first lumen, the distal end of the second
lumen
being open and distal to the distal end of the first lumen, the section of the
second
lumen distal to the proximal end of the dilatation balloon being exterior to
the
20 dilatation balloon, the distal end of the second lumen being open and
distal to the
distal end of the dilatation balloon, and the second lumen being sufficiently
linear
to allow the catheter to be slidingly advanced over a guidewire.
In accordance with an additional aspect of the invention, there is provided
a balloon-expandable stmt percutaneously to a desired site in a patient's body
and
25 deploying such a stmt by expanding it to hold open a body lumen,
comprising: a
catheter shaft defining an inflation lumen and guidewire lumen, the shaft and
each
lumen having proximal and distal ends; an inflatable dilatation balloon having
distal ends, the balloon being affixed to the catheter shaft near the distal
end of the
shaft; wherein the distal end of the inflation lumen opens into and is in
fluid
30 communication with the interior of the dilatation balloon, the guidewire
lumen
defining a proximal guidewire port disposed between the proximal end of the
balloon and the proximal end of the inflation lumen, the guidewire lumen
communicating between the proximal guidewire port and the guidewire distal
end,
whereby the guidewire lumen is adapted to slidingly accept a guidewire, the
disal
CA 02197461 2000-06-05
3d
end of the guidewire lumen being open and distal to the inflation lumen distal
end
and the balloon distal end, the portion of the guidewire lumen distal to the
proximal end of the balloon being exterior to the balloon, the second lumen
being
sufficiently linear to allow the catheter to be slidingly advanced over a
guidewire;
and a flexible stmt crimped around the balloon in a deflated condition, such
that
the stmt will expand when the balloon is inflated.
In the description which follows, reference is made to the accompanying
drawings, in which:
Fig. 1 is a cross-sectional representation of the distal portion of a prior
art
balloon catheter attempting to cross a tight stenosis;
Fig. 2 is a cross-sectional view of a prior art perfusion catheter;
Figs. 3 and 3a are each a cross-sectional view of the distal portion of the
invention illustrating the basic structure of the design;
Fig. 4 is a cross-sectional view of the distal portion of an embodiment of a
dilatation balloon catheter according to the invention;
Fig. 5 is a cross-sectional view in the proximal direction of the
embodiment shown in Fig. 4;
Fig. 6 is a cross-sectional view through the balloon of the embodiment
shown in Fig. 4;
Figs. 7 and 8 are representations of cross-sections of dilatation balloon
catheters according to the prior art and the invention, respectively, within a
stricture to be dilated;
Fig. 9 is a cross-sectional view of the distal portion of another embodiment
of the invention;
25 Fig. 10 is a longitudinal cross-sectional view of a further embodiment of
the invention;
Fig. 11 is a cross-sectional view of the line 11-11 of the embodiment
shown in Fig. 10;
Fig. 12 is a longitudinal cross-sectional view of a yet further embodiment
of the invention;
Fig. 13 is a longitudinal cross-section view of another embodiment of the
invention;
Fig. 14 is a cross-sectional view of the line 14-14 of the embodiment
shown in Fig. 13;
CA 02197461 2000-06-05
3e
Fig. 15 is a cross-sectional view of a modification of the embodiment
shown in Fig. 4;
Fig. 16 is a cross-sectional view of a modification of the embodiment
shown in Fig. 12; and
5 Figs. 17 and 18, are schematic cross-sectional views of a stmt delivery
system according to the invention.
According to the invention herein, the balloon of a balloon dilatation
catheter is mounted eccentric to the catheter shaft, and/or the distal section
of the
guidewire lumen. The distal section of the catheter comprises two or more
10 substantially coextensive lumens wherein the distal portion of one lumen
terminates in a dilatation balloon. Another, second lumen has proximal and
distal
openings to receive a guidewire in a sliding fit. The second lumen may be of
substantially
w0 97100094 ~ PCT/US961I0345
4
equivalent length to the first lumen, ar, alternatively, be shorter, such that
the proximal opening of
the second lumen is substantially distal to the proximal opening of the first
lumen.
In a preferred embodiment, the catheter comprises two substantially
coextensive lumens <>f
equal length, wherein. the distal portion of one lumen terminates in a
dilatation balloon, and the
S second Lumen is open at its distal end and is interrupted near its distal
end to provide an opening
for a guidewire that extends distally through the open di tal end. In this
embodiment, the second
lumen may have a pushing Gvire that extends from the proximal portion of the
catheter to a point
proximal, adjacent, ar distal to the opening. Preferably the second lumen
engages a radiopaque
marker that functions to help break plaque as well as to provide means for
locating the position of
I O the catheter balloon within the vessel.
The invention can perhaps be trotter appreciated by making reference to the
drawrings. The
basic structure of the desi~rr is shown in Figs. 3 and 3a. Figs. 3 and 3a
depict the distal pcmion of
a balloon dilatation catheter 1 having coextensively extending lumens 2 and 3.
Lumen ? terminates
in a dilatation balloon 4 which is inflated and deflated through lumen 2.
Lumen 3 may be banded
15 to balloon 4 as shown in Fig. 3a ar preferably formed from one piece as
shown in Fig. 3
In a preferred embodiment, shown in Fig. 4, lumen 3 contains pushing wire S,
which
extends from the proximal end (net shown) of catheter I to a position 6
proximal, adjacent to, or
within balloon 4. The distal portion of pushing wire 5 is secured by closure,
e.g., heat-slu-inking
of lumen 3, by insertion of a plug, or by other holding or fixation means.
Alsu, the distal portion
20 7 of pushing wire S is preferably tapered distally to provide a smooth
transition in axial stiffness.
The pushing wire 5 wrill became less stiff as the diameter of pushing wire S
narrows in the distal
direction. 'The tapering is substantially linear over the distal portion of
the pushing wire 5.
Optionally, instead of linear tapering, the tapering may be stepped, in
discrete reduc-Lions, c>r
otherwise nonlinear.
25 The distal portion 10 of lumen 3 is enlarged, beginning at a location
proximal to the balloon
4. Opening 9 allows a guidewrire 8 to enter and extend distally through the
open distal end of lumen
3. Preferably, a lubricious lining 14 and a radiapaque marker 15 are included
in the enlarged. '
section 1 Q. Lubricious lining 14 may function to hold the distal portion of
pushing wire ~ between
the inner surface of lumen 3 and the outer surface of lubricious lining 14.
Optionally lining 14 ~
30 could comprise a metal or polymeric coil with a lubricious lining.
SUBSTITUTE SHEET (RULE 28}
WO 97f00094 ~ PCTlUS96/10345
$
Fig. $ represents a cross-sectional view showing how lumens 2 and 3 relate to
one another
and how pushing wire $ is positioned within lumen 3. Lumen walls 12 and 13 can
each have a
thickness of from about 0.3 to 20 rnil, preferably from about 0.$ to 10 mil.
Fig. 6 represents a cross-sectional view through the center of the balloon of
this
$ embodiment. This figure shows how the balloon relates to the enlarged
section 10 of lumen 3, and
to guidewire 8, Preferably, a radiopaque marker 1$ is sandwiched between the
outer surface of
lubricious lining 14 and the inner surface of the wall of enlarged section 10.
In an additional
embodiment, the catheter may have more than one external lumen, preferably
two.
Although Figs. 5 and 6 each appear to represent a one-piece construction, as
shown in Fig.
3a, lumens 2 and 3 may be defined by tubes adhesively or otherwise bonded
together.
Figs. 7 and 8 show dilatation balloon catheters, according to the prior art
and the invention.
respectively, in the application of dilating a stenotic lesion 40 in a blood
vessel 41. As the balloon
of a dilatation catheter is inflated, it exerts a force, F, that corresponds
to the inflation pressure. The
pressure that is exerted against the lesion is proportional to this force, F,
divided by the area upon
1$ which the force is acting (the "contact area"). As shown in Fig. 7, for
prior art balloon catheters the
contact area is equal to the lateral surface area of the balloon 42. For the
catheter of this invention
(Fig. 8) the contact area is not coextensive with the lateral surface area of
the balloon 4. At one
point the contact area is equal to the lateral surface area of balloon 4,
However, at another point,
the contact area is equal to the lateral surface area of the tube that defines
lumen 3. Since lumen
3 has a much smaller area of contact against the lesion than does the balloon
4, the pressure exec~ted
at that point is much greater. Therefore, unnecessarily high balloon inflation
pressures can be
avoided since this design accentuates and focuses the radial farce against the
lesion adjacent to
lumen 3.
The concepts discussed above for Fig. 8 can be represented mathematically by
the formulae
2$ S110i4'17 below':
P = F (I)
A
where P = pressure exerted against a lesion at a given point;
F = Force generated by inflating the balloon; and
A = Contact area.
At the location where the balloon 4 makes contact with the lesion 40, the
pressure; exerted
against the lesion is given by
SUBSTITUTE SHEET (RULE 26)
WO 97100094 PCT/(1596/10345
6
Ps = F (2)
Ag
where AE; = lateral surface area of the balloon.
At the location where the outer wall of lumen 3 makes contact with the lesion
40, the
pressure exerted againstthe lesion is
Pc., = F (3)
A~
where A" = lateral surface area of the outer wall of lumen 3.
Since the lateral surface area of the balloon is much greater than that of the
outer wall of
lumen 3,
AB = CA, , (4)
where C = some factor greater than 1.
The ratio of P« to Pa is determined by dividing equation (~) by equation (2)
and substituting
equation (4)
F
Pu_ = W a_
P~, F
CAS
Pu = CPa (5)
ZO Therefore, far a given balloon inflation pressure, the pressure exerted
against the portion
ofthe lesion adjacent Iwnert 3 is greater than that exerted against the
portion ofthe lesion adjacent
to the balloon.
Additional embodiments, illustrated in Figs. 9 to 11, 13, and 14 provide for
alternate means
to achieve the concentration or focusing of the dilating force. For both of
these cynbodiments, the
?5 section in the eccentric lutrzen 3 that is associated with the dilatation,
i.e., adjacent to the balloon,
has means that form an even smaller contact area with the lesion. Such means
provide somewhat
of a sharp edge, similar to a knife edge, to eut the lesion as the balloon is
inflated. In Fig. 9, the
metal band 17 that serves as a radiopaque marker has a triangular shape, and
is positioned within
lumen 3 such that one side: of the triangle 17 is located under the balloon,
and the opposite apex of
30 the triangle is against the lesion. in the embodiment of Figs. 10 and 1 I,
a section of lumen 3 under
the balloon is cut away. A triangularly shaped wire or guidewire, or some
other knife edge or
cutting instrument 19, can be safely passed through Iwnen 3 and positioned
directly at the lesiota
~tlBSff'NTE SHEEP (RULE ~6~
WO 97/00094 6 ~ PCT/US96I10345
7
through the opening 18. This opening in lumen 3 will also allow drugs to be
delivered directly to
the lesion.
Another embodiment of the invention is shown in Figs. 13 and 14, where lumen
43 contains
pushing wire 45, which extends from the graximal end (not shown) of catheter
41 to a position 46
proximal, adjacent to, or within dilatation balloon 44. The distal portion of
pushing wire 45 is
secured, by closure, e.g., heat-shrinking of lumen of lumen 43, by insertion
of a plug, or by other
holding or fixation means.
The distal portion 50 of lumen 43 is enlarged, beginning at a location
proximal to the
balloon 44. Opening 49 alloGVS guidewire 48 to enter and extend distally
through the open distal
end 4~ of lumen 43. Enlarged section 50 contains a rigid or substantially
rigid, lubricious liner 51
of triangular shage, where one corner of liner 51 extends radially away from
balloon 44. Preferably
liner 51 will be of uniform crass-section, the cross-section being an
equilateral or isosceles triangle,
with a flat surface adjacent balloon 44. The triangular-shaped liner 51 will
function to focus the
dilatation forces, as explained above for Fig. 8. Also, liner 51 may
optionally function to hold the
distal portion of pushing wire 45 between the inner surface of lumen 43 and
the outer surface of
liner 51.
'the rapid exchange embodiment of the invention, for example, the embodiment
shown in
Fig. 4, can also function as an improved, more efficient perfusion catheter.
With the guidewrire
removed from lumen 3, blood will flaw through lumen 3 while the balloon is
inflated. Since the
openings in lumen 3 are collinear with the artery, i.e., collinear with the
direction of the flow of
blood, and are large (compared to the side-hole openings of previously
described perfusion
catheters), there will be significantly less turbulence in the blood flaw
through lumen 3. As a result,
there will be signifrcantly greater blood flaw, and reduced hemolysis compared
to previously
described perfusion catheters. Ivfareover, in an embodiment that employs more
than one eccentric
lumen, andJor an embodiment like that of Fig. 4 in which pushing wire 5 is
replaced with a slidable
guideevire, a guidewire may be left in place (i.e., in a lumen} while blood
flows through an open
lumen.
The embodiments of the invention represented by Figs. 1 ~ and 16,
respectively, have the
ability to exhibit rapidl-single operator exchange capability while
functioning as perfusion
catheters. In Fig. 15 the catheter shaft comprises inflation lumen 62, for
balloon 4, and second
lumen 63, which extends proximally from its distal opening 64. A guidewire 66
slidably fits within
SUBSTITUTE SHEET (RULE 26y
W0 97/01094 PCT/U59G1t0345
~1974bi
8
lumen 63, extending from proximal opening 68 through distal opening Get. The
distal end of a push
wire GS is secured against the wall surface 7d separating lumens 62 and 63 by
lubricious lining 72.
Enlarged porti<m 73 of lumen 63 optionally has a radiopaque marker 75, A
perfusion
opening 76 coaespands to a transition from enlarged portion 73 to toss
enlarged portion 78.
Perfusion can occur with guidewire 66 in place in lumen 63 or when guidewire
66 is partly or
wholly withdrawn proximally. Guidewire 66 could be withdrawn partly so that
its distal portion
still remained within less enlarged portion 78 and then advanced distally when
desired.
According to the embodiment shown in Fig. 16, the catheter shaft has inflation
lumen $2
and lumen 83, which extends from proximal opening 85 to distal opening 86.
Guidewire 88
extends into Lumen 83 through opening 85. Lumen 83 comprises enlarged portion
89 and less
enlarged portion 90. Perfusion opening 92 is positioned at or about the
transition from enlarged
portion 89 to less enlarged portion 90. Perfusion can occur with guidewire 88
in place in lumen
83 or when guidewire 88 is partly or wholly withdrawn from lumen 83. Guidewire
88 could hr"
withdrawn partly so that its distal portion still remains in less enlarged
portion 9tl and then can be
I~ advancetidistally.
According to the invention, the distal section of a balloon dilatation
catheter comprises at
least two substantially, longitudinal coextensive lumens wherein one lumen
terminates in a
dilatation balloon and at least one other lumen is positioned outside, i.e.,
eccentric to the balloon.
1'lte lumen walls 12 and 13 are comprised of materials conventional to balloon
dilatation
catheters. Suitable materials include polyolefins such as polyethylene,
polyethylene terepthalate,
palyurethanes, polyesters, and various copolymers thereof. When used, pushing
wire 5 can be
made from any rigid, medically acceptable material suitable for such use,
including, but not limited
to wires ar hypatubes comprised of stainless steel or other rigid materials.
The construction. according to the invention leads to flexibility in product
design. Far
?~ example, the choice afpushing wire allows the designer to impart various
features to the catheter
in the form of various flexibility and pushability combinations. Also. a
hollow pushing wire, or
deletion ar removal of the pushing wire, would facilitate infusion of fluids,
drugs, andior contrast
media through the catheter into the distal vasculature. Similarly, lumen 2,
used to inflate the
balloon, could have a composite structure, for example, with a distal segment
coextensive wilt
lumen 3 as described above, and a proximal segment made from a holia~v wire,
such as a hypotube
Stl. An example of such an ernbadiment is shown in Fig. 12. Further, it is
within the scope of the
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WO 97/00094 PCT/US96/10345
9
invention that catheter 1 may have at least one additional, coextensive lumen
that would similarly
facilitate infusion of liquids, drugs andlor contrast media. For example, a
catheter 1 with a third,
coextensive lumen open at its distal end could have several possible
applications. Lumen 3 or 43,
and/or respective distal portions 10 or 50, can be sufficiently rigid to
maintain a lumen for perfusion
when dilatation balloon 4 or 44 is inflated. Rigidity may be effected by
various methods known
in the art, such as, for example, material selection, geometric conftguration,
a liner, a coiled wire,
etc.
In a prefen ed embodiment of the invention, as shown in Fig. 4, a lubricious
coating or a
section of thin tubing 14 of lubricious material is sealed into enlarged
section 10. There are several
known materials suitable for this purpose, such as polytetrafluoroethylene
(available as TEFLON~
from duPont), polyethylenes, polysiloxanes, etc. In this embodiment the tubing
section 14 can hold
the distal portion 7 of pushing wire 5, as well as radiopaque marker 15 or 17,
in position.
According to a another embodiment of the invention a slitting means (not
shown) is
mounted proximally on guidewire 8. Then, as the catheter 1 is withdrawn, the
enlarged section
engages the slitting means, the enlarged section 10 is slit, and catheter 1 is
separated from
guidewire 8. This would eliminate the requirement for the operator to change
hands as catheter 1
is removed.
The catheter 1 may have visual length markings along its shaft that would
enable the
operator to predict when the catheter 1 would exit the guiding catheter into
the vasculature. This
would reduce the fluoroscope time. The preferred design would pui the markings
directly on the
pushing wire S (heat shrink tubing rings, inks, paints, etc.). Since pushing
wire 5 is encapsulated
within the second lumen 3, the markings would not be exposed to the patient
(i.e., markings would
not come off, and materials which could be toxic if exposed may be used).
The preparation of a catheter 1 according to the invention can be carried out
by methods and
techniques known to or discernible by those skilled in the art.
Guidewire 8 may be a conventional guidewire, preferably a spring guidewire, as
is well
known. Typical guidewires are shown in U.S. Patents Nos. 4,757,827, 4,815,478,
4,813,434,
4,619,274, 4,554,929, 4,545,390, 4,538,622, 3,906,938, 3,973,556, and
4,719,924. In addition,
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WO 97100094 Ptr'TNS961103d5
The shaft of guidewire 8 could be solid or hollow, such as a hypotube, with an
open distal end,
to facilitate drug infusion.
Operation and use of the angioplasty apparatus of the invention, an embodiment
of which
is shown in Fig. 4, may now be briefly described as follows: A guiding
catheter is inserted into the
5 coronary artery in a conventional manner. The guidewire 8 is then introduced
into the guiding
catheter and advanced to and across the lesion. Now, the balloon dilatation
catheter is inserted'onto
the guidewire and then advanced along the guidewire 8 to and across the
lesion.
After the balloon 4 has crossed the stenosis or lesion, the balloon 4 can be
inflated in a
conventional manner by introducing a radiopaque contrast liquid through the
lumen 2. After the
10 inflation has occurred and the desired operation has been performed by
enla.=grog the opening is
the stenosis, the balloon dilatation catheter 1 can be removed very rapidly by
holding the guidewire
8 stationary and withdrawing the balloon dilation catheter.
If it is ascertained by the operator that additional dilatation of the
stenosis is desired and that
a larger balloon should be inserted into the stenosis, this can be
accomplished very rapidly by
selecting the desired size of balloon dilation catheter and repeating the
aforementioned procedure.
The balloon of the new dilatation catheter can be inflated in the same manner
as hereinbefore
described. If necessary, even another exchange procedure can be readily
accomplished in the same .
manner as hereinbefore described utilizing a still larger balloon dilatation
catheter if that turns out
to be necessary.
After the desired amount of dilation of the stenosis or lesion has been
accomplished, the
balloon dilatation catheter can be removed and thereafter the guiding catheter
can be removed.
As would be appreciated by those skilled in the art, for embodiments in which
lumens 2 and
3 are substantially the same lengths, operation and use of the apparatus would
be in the same
manner as for a conventional over-the-wire balloon dilatation catheter.
In another embodiment of the invention, the eccentric balloon dilatation
catheter can be used
to deliver to a desired site, e.g., within a patient's body, a "balloon
expandable" stem. Such stems
are known in the art, as evidenced by, for example, U.S. Patents Nos.
4,733,665, 4,739,762,
4,776,337, 4,800,882, 4,856,516, 4,878,906, 4,886,062, 4,969,458, 5,037,392,
5, I 33,732,
5,158,548, 5,161, 547, 5,258,020, 5,266,073, 5,382,261, and 5,403,341.
However, it has
been found that the eccentric balloon catheter described herein is especially
suitable for
delivering such stems because the eccentric balloon tends
WO 97!00094 ~ PCTlUS96110345
to retain its position relative to the catheter shaft and increases the
likelihood of mare accurate
positioning (the accordion effect showm in Fig. 1 is an example of the
movement that could occur
with a concentric balloon design for a stent delivery catheter.) Moreover, the
focused force aspects
of the eccentric dilatation balloon design are believed to be more effective
in expanding ar opening
some types of balloon expandable stems than concentric balloon catheter would
be.
To use a catheter herein to deliver a stmt, the stmt in its non-expanded
configuration is
positioned around the deflated eccentric balloon at the distal portion of the
catheter shaft. Then,
the distal portion of the catheter is advanced percutaneously through a guide
catheter, optionally
over a guidewire, to a desired site, e.g., adjacent or across a stenosis or
across a segment where an
stenosis was removal or treated. The balloon is expanded to expand the stmt,
the balloon is
deflated, and the catheter is removed proximally.
A representative embodiment of the stmt delivery system can been seen in Figs.
17 and 18.
in Fig. 17 an unexpended stmt 100 encompassing an uninflated eccentric balloon
102 an the distal
end of catheter 104, has been positioned across a stenosis I OG. When the
balloon is inflated, as
shown in Fig. 18, the stmt 100 expands or dilates, causing the opening in
stenosis 106 to dilate as
well. Balloon 102 is then deflated and the catheter is removed proximally,
leaving expanded stmt
100 in place across stenosis 106.
The preceding specific embodiments are illustrative of the practice of the
invention. 1t is
to be understood, however, that other expedients known to those skilled in the
art or disVased
herein, may be employed without departing from the spirit of the invention or
the scope of the
appended claims.
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