Note: Descriptions are shown in the official language in which they were submitted.
~28"~
BALLOON CATHETER WITH ROTATABLE SUPPORT
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The present invention relates to catheters and
more particularly to an inflatable balloon catheter,
particularly for use in intra-aortic pumping.
Intra-aortic balloon pumping is a recognized method
of cardiac assistance for a failing heart. It is also a
recognized method of treating cardiogenic shock and has been
used to help wean a patient away from cardiopulmonary bypass,
to support a patient during a difficult postoperative period,
and to provide a pulsatile flow to the linear flow supplied
by the cardiopulmonary bypass device. Intra-aortic balloon
pumping has also been used therapeutically after myocardial
infraction to limit the extension of necrosis and has been
used as a therapy for angina pectoris.
Catheters for intra-aortic balloon pumping presently
utilize a nonstressed or nondistensible balloon, i.e., the
~ kalloon is not stretched during inflation and deflation and sub-
- s'cantially never changes its surface area, inflating and de-
flating with a predetermined volume of appropriate fluid to
achieve phasic operation; the balloon surface area is always
substantially equal to that of a fully inflated balloon. The
intra-aortic balloon catheters of the prior art are relatively
~13Z8'~ 6
stiff and bulky and have a large "entering" cross-section.
The femoral artery has heretofore been used for insertion
of these stiff and bulky intra-aortic balloon catheters
because of the large diameter of that artery. However, con-
siderable surgery must be performed in order to reach and
isolate the femoral artery. In addition, a large incision
must be made in the femoral artery wall to permit introduction
of these prior art devices. The safeness of intra-aortic
balloon pumping using the catheters of the prior art has been
questioned since they can cause and in some instances have
caused aortic dissections, perforations and trauma mainly
because of the entering size and the relative siffness of the
devices. Additionally, this stiffness prevents precise maneu-
verability of the catheter within the vascular structure andthereby limits its potential for efficacy.
It is recognized in the prior art that insertion and
guiding of catheters is difficult and that trauma and damage
to the incision and blood vessel may occur during said inser-
tion and guiding. The balloon of prior art catheters iscommonly rolled or spirally wrapped around its underlying
catheter tube in order to insert it into and guide it in a
blood vessel. In Grayzel, ~.S. Patent No. 3,939,820, an
attempt is made to obtain a tight wrap in which the size of
the enclosed catheter tube is decreased by replacing it with
1~3ZB76
a thin support member or wire. The balloon membrane, however
must still be wrapped, or rolled, and the limited amount of
balloon material available and the limited magnitude of the
torsional stress that may be applied to twist the balloon
limit the tightness of the roll regardless of whether the
balloon is twisted around a catheter tube or around a thin
support member. In catheters of the prior art, the balloon
tip and gas supply tube are rigidly connected to each other
within the balloon (Goetz et al., U.S. Patent No. 3,692,018
and Jones, U.S. Patent No. 3,504,662), or are rigidly connec-
ted to each other by a thin support member within the balloon
(Grayzel, U.S. Patent No. 3,939,820), or are connected to each
other within the balloon by a non-twistable, copper current-
carrying braid (Kantrowitz et al., U.S. Patent No. 3,585,983).
The twisting of the balloon about its longitudinal axis is
therefore limited since no rotational displacement is possible
between the balloon tip rigidly fastened to the distal end of
the balloon and the catheter tube or support means ri~idly
fastened to the proximal end of the balloon.
In accordance with the present invention, a new and
improved catheter is provided in which the chamber or inflat-
able balloon of the catheter may be tightly twisted into a
small cross-sectional diameter. A smaller entering diameter
for the catheter may thereby be obtained enabling the catheter
to be inserted into smaller incisions and body openings and
guided through smaller and more tortuous canals and passageways.
11328 ~ ~i
It is an object of the present invention to provide
a new and improved catheter.
It is also an object of the present invention to
provide a catheter capable of being configured into a cross
section no larger than that of the inflating gas supply tube
of the catheter.
It is an object of the present invention to provide
a catheter which may be inserted through small incisions or
even by percutaneous insertion.
It is another object of the present invention to
provide a catheter having support means one end of which is
rotatable relative to the chamber and the remainder of the
catheter.
It is still another object of the present invention
to provide a catheter incorporating a sheath facilitating
atraumatic insertion of the catheter into blood vessels or
- body openings.
It is yet another object of the present invention to
provide a catheter capable of being axially shaped or formed
by the surgeon to facilitate passage of the catheter into a
tortuous blood vessel or bifurcation.
It is another object of the present invention to
provide single and ~ulti-chambered catheters embodying the
aforementioned objects.
In accordance with the invention, the chamber of the
.
11~2~`~ 6
catheter is supported about support means, one end of the
support means being rotatable relative to the chamber wherein
the chamber is adapted to being compactly wrapped, rolled or
twisted about the support means upon swiveling of the support
S means. The support means is of small diameter and is disposed
within the chamber connected with the chamber at one end thereof
and rotatable with respect to the remainder of the catheter at
the other end of the chamber whereby the support means may be
rotated or swiveled relative to the catheter. Rotatable dis-
position of the support means in the catheter chamber at oneend thereof permits tight twisting of the chamber about the
support means without distorting or damaging the conduit means
for transmitting fluid into and out of the chamber. Thus, the
torque applied to the chamber in twisting it is not imparted
to the conduit means and the remainder of the catheter.
In the preferred embodiments, the chamber and support
means are connected at the distal end of the chamber, and the
support means are rotatably secured to the conduit means at
the proximal end of the chamber, distal and proximal being
referenced with respect to the connection of the chamber to
the conduit means. Also in the preferred embodiments, the
catheter is utilized for intra-aortic balloon pumping.
A catheter according to the disclosed embodiments of
the invention comprises gas supply means for transmitting gas
into and out of the balloon and an elongated, rod-like support
~132B','6
member in the balloon for supporting the balloon, the proximal
end of the balloon being non-rotatably connected to the gas
supply means and the support member being rotatably secured to
the gas supply means. Means are provided to prevent the rota-
table support member from telescoping or collapsing as the
catheter is inserted and guided during use. The distal end
of the balloon is non-rotatably connected to the support
member. The balloon is wrapped about the support member by
rotation of the distal end of the balloon.
In accordance with another aspect of the invention,
a sheath is provided to enclose the balloon in the wrapped
configuration thereof. The sheath is thin-walled, smooth and
has a low coefficient of friction to thereby facilitate entry
and guiding of the catheter and to reduce trauma.
In accordance with still another aspect of the inven-
tion, the support means is a thin flexible wire which may be
formed into and retain a desired axial shape during use. This
enables 'che catheter to be guided into and through a bifurca-
tion or tortuous body canal or vessel.
Smaller entering diameters and controllability of
catheters according to the invention, combined with the ease
of insertion, makes it possible to insert such catheters into
smaller and more accessible arteries than the femoral artery,
for example, the brachial or the axillary artery. Intra-
aortic balloon pumping can be carried out with catheters
113'Z~3',.'~
according to the invention without undergoing the extensive
surgery of a femoral arteriotomy and therefore may become
available to many more patients. Those patients for whom the
standard transfemoral approach is impossible because of athero-
matous femoral arteries, obstructive aortoiliac disease, or acontaminated or previously cannulated groin may now be treated
by the more easily inserted and more flexible catheters of the
invention.
It is therefore contemplated that the catheters
according to the present invention will make intra-aortic
balloon pumping available to many more people than can now be
treated by the use of the relatively stiff, bulky prior art
balloon catheters and the obligatory use of the femoral
arteries because of the large "entering" bulk of the prior
art catheters.
It is also within the contemplation of the present
invention that the catheters of the invention be percuta-
- neously insertable, i.e., insertable through the skin without
surgery.
These and other aspects of the invention will be
more apparent from the following description of the preferred
embodiments thereof when considered with the accompanying draw-
ings and appended claims.
The present invention is illustrated by way of example
and not limitation in the figures of the accompanying drawings
in which like references indicate similar parts and in which:
Fig. 1 is a side view, partly in section, of the
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catheter according to the invention showing the balloon thereof
in an untwisted configuration;
Fig. 2 is a side view, partly in section, showing the
balloon of the catheter of Fig. 1 in its twisted or wrapped
configuration;
Fig. 3 is a section view taken along 3-3 of Fig. 2;
Fig. 4 is a side view, partly in section, of a prior
art catheter showing the balloon thereof in a rolled or twisted
configuration;
Fig. 5 is a section-view taken along line 5-5 of the
prior art catheter of Fig. 4;
Fig. 6 is a side view, partly in section, of a dual-
chamber catheter according to another embodiment of the inven-
tion; and
Fig. 7 is a sectional view of the balloon portion of a
balloon catheter according to another embodiment of the inven-
tion in which the support means are rotatably coupled to the
catheter tip.
As shown in Fig. 1, catheter 20 according to the
invention includes a hollow, flexible catheter gas supply tube
22 affixed at one end 24 thereof to connector 26 and adjacent
the other end thereof to an elastomeric balloon 2a. Catheter
20 is an omnidirectional intra-aortic balloon catheter and
includes the single balloon chamber 30. In accordance with
the preferred embodiments illustrating the invention and not
by way of limitation, the balloon is not stressed during in-
flation and deflation, i.e., the balloon is non-distensible
,f~., '
,, ,~,~
1~328~'6
and has substantially the same surface area when inflated and
when deflatedO A rigid tip 32 is fluid-tightly affixed to the
distal end 34 of the balloon. The gas supply tube 22 terminates
in end 36 adjacent proximal end 38 of balloon 28 which is dis-
posed within chamber 30 of balloon 28 a small distance suffi-
cient to acoxF~date within chamber 30 a plurality of gas ports
40 in gas supply tube 22. The gas ports 40 communicate the
interior of the gas supply tube with chamber 30. The proximal
end 38 of the balloon is fluid-tightly bonded circumferentially
t.o gas supply tube 22 and the distal end 34 of the balloon is
fluid-tightly bonded circumferentially to tip 32 by, for
example, an adhesive or by welding. The tip, balloon and gas
supply tube are coextensive at least in part to form a con-
tinuous member having good flexibility at the junction of the
tip and balloon and the gas supply tube and balloon.
Tip 32 includes an end portion 42 having a section 44
of reduced diameter and a sleeve 46. The sleeve is fluid-
tightly circumferentially bonded about section 44 and the
balloon end is fluid-tightly circumferentially bonded to the
sleeve by, for example, an adhesive or by welding. The parts
of tip 32, sleeve 46 and tube 22 within chamber 30 are smoothly
contoured to reduce stress and wear on the balloon during opera-
tion thereby preventing puncturing, cutting or rupturing of the
balloon.
Interposed between tip 32 and tube 22 in chamber 30
,,~
- 10
~1328', 6
is support wire 50. End 52 of the support wire is non-
rotatably secured in hole 54 of tip 32 and end 56 is rotatably
disposed in opening 58 of tube end 36. End 52 extends into
tip 32 and is soldered therein or non-rotatably affixed therein
by other means such as adhesives, for example. End 52 abuts
against the end of hole 54 and together with the non-rotatable
affixing of end 52 to tip 32 prevents movement of wire 50
towards the distal end 34 of the balloon. A disc-shaped keeper
60 secured to the wire 50 adjacent tube end 36 prevents movement
of the wire toward the proximal end 38 of the balloon and pre-
vents the wire from being forced further into the end of tube
22 when pressure is applied to the balloon during insertion of
the catheter. Opening 58 permits wire 50 to rotate freely
therein. The end 56 of the wire extends sufficiently into
tube 22 to prevent the wire from being withdrawn through open-
ing 58. Wire end 56 at the extremity 61 thereof is rounded
to prevent damage to the wall of tube 22.
In accordance with the invention, the provision of
the thin support wire 50 rotatably disposed in the gas supply
tube permits the support wire to be rotated or swiveled rela-
tive to the gas supply tube, thereby permitting the balloon
to be easily and compactly twisted about the support wire.
This results in the twisted balloon having a smaller cross-
sectional area which approaches that of tip 32 and gas supply
tube 22. Thus, the overall cross~sectional area of catheter 20
~ .
il3Z8'~'6
may be reduced for insertion into smaller incisions.
Additionally, the torque applied to twist the balloon during
wrapping thereof is not imparted to the gas supply tube thereby
preventing stress to and damage of the gas supply tube.
In use, balloon tip 32 is grasped and rotated tightly
twist balloon 2~ about the thin wire support 50. Since the
wire may be freely rotated within tube end 36, the tip may be
rotated for many revolutions to impart a compact twist to the
balloon as shown in FIG. 2. As the balloon is twisted about
its own axis, its cross-sectional area is reduced, as shown in
FIG. 3, and the cross-sectional area is inversely proportional
to the number of rotations of the tip. Thus, the largest
cross-sectional diameter of the catheter is that of the twisted
balloon which approaches that of tip 32 and gas supply tube 22.
A vacuum is applied to the interior of the wound balloon to
keep it from unwinding. After insertion when the balloon is
in the desired position, the vacuum is removed and the balloon
unwinds. In contrast, the much larger cross-sectional configu-
ration of a prior art catheter in which the balloon is wrapped
on the interior support or catheter tube is shown in FIGS. 4
and 5. The largest cross-sectional diameter 62 of the wrapped
balloon 63 is considerably larger than the cross-sectional
diameter 64 of the catheter tube 65.
After the balloon has been twisted about the support
wire as shown in FIGS. 2 and 3, a sheath 66 (FIG. 1) may be
slid over the balloon to enclose it and enhance performance
12
~3Z8~, 6
of the catheter. However, it is to be understood that the
present invention as described above may be practiced without
the sheath and that the sheath may be used to enhance perfor-
mance. The sheath also prevents the balloon from unwinding.
When a sheath is used, the vacuum may optionally be applied
to the interior of the wound balloon. The sheath 66 is thin-
walled and made of a low friction flexible material such as
Teflon, Mylar or polyethylene. When used, it is positioned
on the gas supply tube 22 adjacent the balloon 28 (FIG. l)
pxior to its being drawn over the twisted balloon. In
addition to locking the balloon in its twisted configuration,
the sheath is smooth-walled and, as mentioned, is made of low
friction material to facilitate insertion of the catheter.
Sheath 66 is sufficiently long so that a portion thereof
remains exposed after the catheter has been advanced to the
desired location. The exposed portion is used to withdraw
the sheath from over the twisted balloon and return it to its
position on the gas supply tube 22. The balloon will then
unwind due to the elastomeric nature of the balloon material
and the inflating gas pressure. The sheath facilitates
atraumatic entry of the catheter into the incision and blood
vessel and facilitates insertion and guiding of the catheter
in the blood vessel, however, as mentioned, use of the sheath
is not mandatory.
A gas supply source 68 is connected to the catheter
~3Z~6
by means of the connector 26 and supplies and withdraws gas
to the gas chamber 30 through gas supply tuhe 22 to achieve
phasic operation of the catheter for the intra-aortic balloon
pumping procedure.
The support wire 50 is preferably made of a material
which may be formed during use into a desired axial configura-
tion by bending. For example, the surgeon may bend the support
wire near the distal tip 32 of the balloon to facilitate entry
of the catheter into a tortuous blood vessel or bifurcation.
The shape of the support wire may be formed with or without
the balloon twisted thereabout.
The present invention may be embodied in dual or
multichamber catheters in addition to the single chamber cathe-
ter described hereinbefore. Referring to FI5. 6, dual-chamber
catheter 70 includes a second or occluding balloon s~ction 72
in addition to the pumping balloon section 74 similar to balloon
28 of FIG. 1. Occluding balloon section 72 is bonded to tube 22
at end 76 of the balloon as described for balloon 28. The neck
78 between the balloon sections insures that the occluding
balloon 72 is inflated before the pumping balloon 74 is inflated,
thereby insuring optimal unidirectional balloon pumping action.
It is understood, however, that the position of the occluding
balloon 72 may be other than between balloon 74 and connector 26.
In some instances, unidirectional pumping is more efficacious
if the occluding balloon 72 is placed between tip 32 and the
14
i~32B~f6
pumping balloon is shown in FIG. 3 of Grayzel, IJ.S. Patent
No. 3,939,820. While a single balloon is shown which forms
separate balloon chambers, the multi-chamber catheter may com-
prise separate balloons. The distal tip and proximal end of
the catheter tube may be configured as shown and described for
the balloon catheter of FI5. 1. Alternatively, a rigid tip 80
may be provided having a section 82 of reduced diameter, a
sleeve 84 and a plug 86. The sleeve is fluid-tightly circum-
ferentially bonded about section 82 and the balloon end is
fluid-tightly circumferentially bonded to the sleeve by, for
example, an adhesive or by welding. The parts of tip 80 and
tube 22 including plugs 86 and 88 within the chambers are
smoothly contoured to reduce stress and wear on the balloon
during operation thereby preventing puncturing, cutting or
rupturing of the balloon.
Interposed between tip 80 and tube 22 in chambers 90,
91 is the support wire 50. End 52 of the support wire is non-
rotatably secured in hole 92 of plug 86 and end 56 is rotatably
disposed in hole 94 of plug 86. A disc 96 is soldered to the
end of 52 of the wire which protrudes through plug 86, the disc
abutting against section 82 of tip 80. This, together with the
securing of the wire within hole 92 by means of, for example,
an adhesive, prevents movement of wire 50 towards the distal
end 98 of the balloon. Wire 50 includes a section 100 of
enlarged diameter adjacent plug 88 which prevents movement of
- 15
i ~ ~ Z ~
the wire toward the proximal end 76 of the balloon and prevents
the wire from being forced further into the plug and tube 22
when pressure is applied to the balloon tip durina insertion
of the catheter. Hole 94 is sized to permit wire 50 to rotate
freely therein. Section 100 is shown to be a spherically-
shaped keeper, however, other shapes will also be suitable.
The end 56 of the wire extends sufficiently into tube 22 to
prevent the wire from being withdrawn through hole 94 of plug 88.
Wire end 56 at the extremitv 61 thereof is rounded to prevent
damage to the wall of tube 22, as described for the catheter
shown in FIG. 1.
The catheters according to the invention are fabricated
of biologically acceptable material. The tube 22 is formed, for
example, or polyurethane. Tip 32 is formed, for example, from
stainless steel of Lexan* and the connector, from polyethylene
or polypropylene. Balloon 28 (72, 74) is made, for example, of
a thin film of polyurethane. Other biologically acceptable
material5 may also be used. Gases such as air, carbon dioxide
and helium or liquids are used to inflate the catheter when
used for intra-aortic balloon pumping.
While the invention has been illustrated with the
support wire rotatably secured to the gas supply tube and non-
rotatably connected to the distal tip, it is to be understood
that it is contemplated according to the invention that the
support wire may be rotatably secured to the distal tip and
*: trade mark
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:
16
l,~3~z~,)',.'G
non-rotatably connected to the gas supply tube.
Such an embodiment is illustrated in Fig. 7. Catheter
110 includes a tip 112 which has a hollow portion 114 therein.
Tip 112 is similar to tip 80 illustrated in Fig. 6. In a
manner similar to that described for tip 80 of Fig. 6, a sleeve
116 is bonded to tip 112 and a plug 118 is secured in sleeve
116. The support wire 50 extends through the central opening
in the plug 118 and clearance is provided so that the wire is
freely rotatable with respect to the plug. The support wire 50
terminates in a rounded section 61 in the hollow portion 114 of
the tip 112. At the proximal end of the chamber, the support
wire 50 is non-rotatably secured to the catheter tube portion 22
by means of, for example, a plug 120 similar to plug 88
illustrated in Fig. 6. The wire 50 terminates at plug 120 and
is, for example, welded thereto.
In the embodiment illustrated in Fig. 7, the chamber
is wound about the support means by grasping the distal end of
the chamber and rotating the tip relative to the support wire
and the proximal end of the chamber to wind the chamber about
the support wire. In either case, the invention is practiced
in that the balloon may be rotated relative to the support wire.
The advantages of the present invention, as well as
certain changes and modifications of the disclosed embodiments
thereof, will be readily apparent to those skilled in the art.
It is the applicants' intention to cover by their claims all
those changes and modifications which could be made to the
embodiments of the invention herein chosen for the purpose of
- 17 -
11;~2~ G
the disclosure without departing from the spirit and scope of
the invention. Protection by Letters Patent of this invention
in all its aspects as the same are set forth in the appended
claims is sought to the broadest extent that the prior art
allows.
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