Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MULTI-CANNULA CATHETER FOR ADMINISTERING THERAPY TO
DISPARATE POINTS IN A VESSEL IN WHICH FLUID FLOW PAST
THE CATHETER IS PRECLUDED
Field of the Invention
The present invention generally relates to a mufti-cannula catheter, and
more specifically, to an assembly having a catheter with a distal end that is
movable relative to the distal end of another catheter.
Background of the Invention
A conventional catheter is a flexible tube having one or more lumens
extending longitudinally therethrough. The distal end of a catheter is
typically
inserted into a body lumen, such as a blood vessel, and advanced to a site
where a
medical treatment is to be administered that often involves the infusion of
medicinal fluids, withdrawal of bodily fluids, or the monitoring of pressure
via the
lumens formed in the catheter. Catheters are also frequently used to support a
medical device, such as an angioplasty balloon or a sensor for monitoring p02
or
pC02. The lumens in a catheter may serve as passages through which electronic
leads extend to such a sensor, or can be used for conveying a fluid that
inflates a
balloon. In addition, fluid can be administered to a specific treatment site
within a
patient's body through a lumen in a catheter.
Certain kinds of diseases of the vascular system are best treated locally
rather than systemically. A systemically administered medication can have
undesired effects on a patient, particularly if administered in sufficient
concentration to be therapeutically effective at the diseased site in a
vessel. Once
administered systemically, a medication spreads throughout the patient's body
and
becomes diluted in the blood stream; however, a substance can also become too
concentrated in an organ such as the kidney. Clearly, the benefit of a
medication
will be optimized and its adverse effects minimized if the medication is
administered at the site where the therapeutic benefit of the medication is
needed
most. A conventional catheter is capable of administering a medication to a
diseased site in a blood vessel or other body lumen. However, in a blood
vessel,
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the medication is generally not retained at the site where it is administered
via the
catheter. Instead, once the medication is infused through a lumen in a
catheter at
the site within the vascular system, the blood flowing through the vessel will
cause the medication to be dispersed into other parts of the patient's body.
When a vessel has been diseased for some time, it is often the case that
concomitant damage will occur in other parts of the body in which blood
flowing
through the vessel circulates. In such cases, it may be desirable to
simultaneously
administer different medications to treat both the diseased vessel and the
damage
to another portion of the patient's body caused by the diseased vessel.
Currently,
there is no catheter system available that can be advanced through a vessel,
particularly a vein, and provide different medicinal fluids to disparate sites
within
the vessel.
As noted above, it would also be desirable to retain the medication
delivered to a site through a catheter at the site until the medication can
have its
beneficial effect. While a balloon disposed adjacent a distal end of a
catheter is
sometimes used to block blood flow past the catheter during administration of
a
medication or during some other procedure, the balloon must be inflated with
an
external source of fluid that is conveyed through one of the lumens of the
catheter.
In some applications, it will be preferable to minimize the diameter of the
catheter, avoid unnecessary dilation of the vessel, and avoid damage to the
endothelium of the vessel. Accordingly, an alternative mechanism for blocking
blood flow through a vessel around a catheter would be very useful - both on a
catheter that enables medicinal fluids to be infused at disparate sites within
a body
lumen, and on other types of catheters. It would also be desirable to allow
the
simultaneous delivery of medicinal fluids without mixing these fluids to avoid
causing potential reactions (crystallization, for example) in the catheter.
Summary of the Invention
In accord with the present invention, a catheter assembly is defined that is
usable for administering a first liquid to a first site in a body lumen of a
patient
and a second liquid to a second site in the body lumen, where the second site
is
substantially spaced apart from the first site. The catheter assembly includes
a
first tube that is flexible and elongate, having a guide lumen extending at
least
along part of its length. The first tube has a proximal port adapted to
introduce the
first liquid into a lumen, and a distal port coupled in fluid communication
with the
lumen and thus adapted to supply the first liquid to the first site. A second
tube
that is flexible and elongate has a lumen extending therethrough it, and the
lumen
couples a proximal port in fluid communication with a distal port on the
second
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tube. The second tube is smaller in cross-sectional size than the guide lumen
of
the first tube. This configuration enables a position of the distal port of
the second
tube to be adjusted in the body lumen relative to a position of the distal
port of the
first tube, by sliding the second tube through the guide lumen to adjust its
position
relative to the first tube. The first liquid can be administered to the first
site
through the lumen and the distal port of the first tube, and the second liquid
can be
administered to the second site through the lumen and the distal port of the
second
tube.
In one embodiment, the distal port of the first tube is disposed in a wall of
the first tube. In a different embodiment, the guide tube comprises the lumen
through which the first liquid is administered. In this embodiment, the distal
port
of the first tube comprises a gap defined between the outer surface of the
second
tube and an inner surface of the guide lumen of the first tube. A seal on the
proximal end of the first tube preferably includes an adjustable compression
fitting that is engaged to lock the second tube at a desired position in the
guide
lumen of the first tube.
In some forms of the invention, the second tube includes at least one
additional lumen extending longitudinally through it. Similarly, in some forms
of
the invention, the first tube includes at least one additional lumen extending
longitudinally through it.
In one embodiment, the assembly includes a skirt having a distal end and a
proximal end. The proximal end of the skirt is attached in sealing
relationship
around an outer surface of the first tube, adjacent to its distal end, while
the distal
end of the skirt is adapted to seal against an internal surface of a body
lumen in
which the catheter apparatus is inserted, thereby preventing bodily fluid from
flowing past the distal end of the first tube in a direction toward the
proximal end
of the first tube.
In several embodiments, the skirt includes a biasing element that acts on
the skirt, forcing at least a portion of the skirt radially outward into
sealing
relationship with the inner surface of the body lumen when the skirt is
enabled to
unfurl. In one embodiment of the skirt, the biasing element comprises a
helical
coil spring disposed radially within an interior of the skirt. Another
embodiment
includes a biasing element that comprises a super elastic alloy having a
radially
expanded memory shape. In still another embodiment, the skirt is wrapped
around the catheter and deploys into a lily-like shape. In yet another
embodiment,
a plurality of struts extend distally from a distal edge of the skirt and are
connected to the outer surface of the catheter to prevent the skirt from
prolapsing.
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Still another embodiment employs a skirt having a generally spherical shape
that
remains collapsed until released and enabled to expand outwardly into contact
with the inner surface of the body lumen. It may be preferable to include a
sleeve
that encompasses the skirt, keeping the skirt furled about the outer surface
of
either the first or the second tube while the catheter assembly is being
advanced
through a body lumen. The sleeve may extend proximally of the patient's body
or
alternatively, a line can be connected to the sleeve and extend outside the
body
lumen to enable the sleeve to be pulled from the skirt so that the skirt can
unfurl to
obstruct the flow of the bodily fluid through the body lumen. The sleeve can
be
withdrawn from the skirt after the distal port of the first tube or second
tube is
disposed proximate the corresponding first site or second site. It will be
apparent
that the skirt can also be used on a catheter assembly that does not include a
plurality of cannulas.
In another aspect of the present invention, a method for administering first
and second fluids respectively to disparate first and second sites within a
body
lumen is defined. The method includes steps generally corresponding to the
functions of the elements discussed above.
Brief Description of the Drawing Figures
The foregoing aspects and many of the attendant advantages of this
invention will become more readily appreciated as the same becomes better
understood by reference to the following detailed description, when taken in
conjunction with the accompanying drawings, wherein:
FIGURE 1 is a side view of portions of a catheter assembly including an
inner catheter and an outer catheter, in accord with the present invention;
FIGURE 2 is an enlarged side view of a portion of the catheter assembly
shown in FIGURE 1, at a distal end of the outer catheter;
FIGURE 3 is a cross-sectional view of the catheter assembly taken along
section line 3-3 in FIGURE 2;
FIGURE 3' is an alternative cross-sectional view of the catheter assembly
taken along section line 3-3 in FIGURE 2;
FIGURE 4 is a side view of portions of an embodiment of a catheter (e.g.,
the inner catheter) showing a skirt that is unfurled to block blood flow past
the
catheter in a vessel;
FIGURE 5 is a side view of portions of another embodiment of a skirt on a
catheter;
FIGURE 6 is an enlarged cross-sectional view of a portion of the catheter
and the skirt shown in FIGURE 5;
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FIGURE 7 is an enlarged side view of a different embodiment of the skirt
on a portion of a catheter;
FIGURE 8 is an enlarged view of the distal end of the embodiment of the
skirt and catheter shown in FIGURE 7;
FIGURE 9 is an enlarged side view of yet another embodiment of the skirt
on a portion of a catheter;
FIGURE 10 is an enlarged side view of still another embodiment of the
skirt on a portion of a catheter;
FIGURE 11 is an enlarged side view of an embodiment of a skirt that
includes a helical spring biasing coil and a portion of a catheter;
FIGURES 12A and 12B are respectively an enlarged side view and an end
view of a portion of a catheter and an embodiment of a skirt that is lily
shaped and
extends around the catheter;
FIGURE 13 is an enlarged view of a portion of a catheter and a generally
spherical shaped embodiment of a skirt;
FIGURE 14 is a cross-sectional longitudinal view of a blood vessel
showing a catheter assembly having an inner and outer catheter being advanced
through the blood vessel;
FIGURE 15 is a cross-sectional longitudinal view of the blood vessel of
FIGURE 14, showing a skirt around the inner catheter unfurled to block blood
flow through the blood vessel; and
FIGURE 16 is a side view of portions of an alternative embodiment of a
multi-cannula catheter assembly, in accord with the present invention.
Description of the Preferred Embodiment
With reference to FIGURES 1 through 3 and 3', a multi-cannula catheter
assembly 20 is illustrated. Mufti-cannula catheter assembly 20 includes an
inner
catheter 22 and an outer catheter 24. While the embodiment of the present
invention shown in these Figures depicts inner catheter 22 extending
concentrically along the longitudinal axis of outer catheter 24, it will be
appreciated that a guide lumen within outer catheter 24 for use in guiding
inner
catheter 22 may be offset to one side of the longitudinal axis of outer
catheter 24,
as would likely be the case if the outer catheter includes a plurality of
lumens.
While not shown in these Figures, it will be apparent that outer catheter 24
can
include additional lumens besides the guide lumen through which the inner
catheter is slidably disposed. Suitable materials for fabricating these and
other
catheters discussed below include PEBAXTM, high-density polyethylene (HDPE),
NYLONTM, urethane, and polyvinyl chloride (PVC) plastics.
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Outer catheter 24 includes an external portion 26 having a side tube 28 that
is connected in fluid communication with the guide lumen in this embodiment.
If
additional lumens are provided in outer catheter 24, corresponding additional
side
tubes similar to side tube 28 would typically be included, generally one for
each
of the lumens provided in the catheter that convey a fluid, or through which a
lead
or some other element is threaded. Side tube 28 includes a female Luer fitting
30
adapting the side tube to connect to a tube set having a corresponding male
Luer
fitting (not shown). Fluid can either be introduced or withdrawn from the
guide
lumen (or other lumens provided with similar side tubes) via the side tube
that is
connected in fluid communication with that lumen. For example, a medicinal
fluid can be supplied to a treatment site from an external source of the fluid
that is
coupled to side tube 28. The fluid is introduced into and conveyed through the
lumen to the distal port disposed at the treatment site. A seal 32 is
compressively
engaged around inner catheter 22, forming a fluid-tight seal that prevents
fluid
introduced through side tube 28 from leaking past inner catheter 22 where it
extends through the seal.
Similarly, the proximal portion of inner catheter 22 includes at least one
side tube 48, which is provided with a female Luer fitting 50 for engaging a
tube
having a corresponding male Luer fitting. It will be apparent that fluids can
be
both withdrawn and administered to a patient via side tube 48 through the
lumen
of inner catheter 22 and that additional lumens coupled in fluid communication
with corresponding additional side tubes can be included. A seal 52 is adapted
to
compressively engage a guide wire (not shown in FIGURE 1 ). The guide wire,
which is initially inserted into a body lumen and advanced through the body
lumen at least to a site where the distal end of the inner catheter will be
disposed,
is threaded through at least one lumen of the inner catheter and serves to
guide the
catheter assembly to this site within the body lumen. In most cases, the body
lumen will be a blood vessel in a patient's body. Seal 52 prevents fluid in
this
lumen from leaking proximally past the guide wire.
A portion 34 of outer catheter 24, which is adapted to be inserted within a
body lumen of a patient, includes a port 36 formed near a distal end 38. Also
disposed proximate distal end 38 of the outer catheter is a band 40, which may
be
visualized using a variety of imaging modalities to assist in monitoring the
position of the distal end of the outer catheter relative to a site to which
fluid is to
be delivered through the outer catheter. Similarly, a distal end 42 of the
inner
catheter also includes band 40, adjacent a distal port 44 for at least the
lumen
through which the guide wire is initially threaded. In the enlarged view of
the
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distal end of outer catheter 24, shown in FIGURES 3, and 3', it will be
apparent
that a gap 60 is formed between the distal portion of the inner catheter and
the
internal surface of the outer catheter at its distal end 38. Fluid flowing
through the
guide lumen can thus pass through gap 60. Thus, as indicated by the dash line
in
FIGURE 2, distal port 36, which is formed in the side wall of the outer
catheter, is
optional. Also shown in FIGURE 3 is a guide wire 54 disposed within a central
lumen 56 at the distal portion of inner catheter 22.
In FIGURE 3', an embodiment is shown in which a lumen 56' and a
lumen 56" are formed within inner catheter 22 in side-by-side relationship. A
guide wire 54' extends through lumen 56' in this embodiment. Gap 60 is again
provided to enable fluid passing through the guide lumen of outer catheter 24
to
be infused into the body lumen at the distal end of the outer catheter (as an
alternative to being infused through distal port 36).
It will be apparent that inner catheter 22 can be slidably adjusted within
the outer catheter so that the distal end of the inner catheter and its distal
port 44
are spaced apart from distal end 38 of outer catheter 24 by a desired extent.
The
spacing between the distal ends (or distal ports) of the inner and outer
catheters is
adjustable to enable different fluids to be separately administered to
different
treatment sites within a body lumen through mufti-cannula catheter assembly
20.
To adjust the spacing between the distal ports on the inner and outer
catheters, one
of the catheters is moved relative to the other catheter either before or
after the
mufti-cannula catheter assembly is inserted within the body lumen of a
patient's
body. If the adjustment is made after insertion of the catheter assembly into
the
body lumen, the whole assembly will typically be advanced along the guide wire
until the distal port of the inner catheter is at its desired site within the
body
lumen, and then the outer catheter will be drawn back over the inner catheter
until
the distal port (or distal end) of the outer catheter is disposed at its
desired site in
the body lumen. Use of bands 40 enable the disposition of the distal ports or
ends
of the inner and outer catheter to be determined within the patient's body
with
imaging modalities so that they can be positioned within the body lumen at the
desired sites.
Each of the catheters may be used to deliver specific drugs, blood, gene
therapies, or therapeutic agents to the treatment site where the distal port
of each
of the respective catheters is ultimately disposed within the patient's body.
Further, although only two catheters are disclosed in the drawings, it will be
apparent that a third or more catheters can be added and similarly threaded
through either a lumen of a concentrically outer catheter, or through a
different
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lumen in outer catheter 24, to treat additional sites within the body lumen at
different spaced-apart locations. The disposition of the sites will depend
upon the
anatomical variations and differences in the disease locations from patient to
patient, and the adjustable nature of the mufti-cannula catheter assembly
permits
the fluids to be administered to the appropriate sites.
FIGURE 16 illustrates an alternative embodiment of a mufti-cannula
catheter assembly 150 that includes catheters 152 and 154. In this embodiment,
the same components are provided at the proximal ends of the two catheters
that
remain outside the patient's body as in the embodiment first discussed above.
However, in this embodiment a distal end 156 of catheter 152 extends through a
relatively short distal portion 158 of catheter 154 in which the guide lumen
is
disposed. In addition, catheter 154 includes a much longer section 160 through
which a lumen (not specifically shown) extends, in fluid communication with
side
tube 28. Fluid administered through side tube 28 and flowing through this
lumen
exits from a distal port 162 of distal portion 158.
Included proximal to the distal end of catheter 152 is a skirt 90, the
purpose and details of which are discussed below. Fluid administered through
side tube 48 of catheter 152 flows through a lumen in the catheter (not
separately
shown) and exits the lumen through distal port 44, at the distal end of the
catheter.
Catheter 152 is freely slidable through the guide lumen within distal portion
158
of catheter 154, so that the distal ends and distal ports of each catheter may
be
spaced apart within a body lumen to deliver different fluids to
correspondingly
spaced-apart sites through the distal ports of the two catheters. The
relatively
short guide lumen in distal portion 158 serves the dual function of providing
a
path for the coaxial delivery of catheter 152 and of serving as a sleeve for
keeping
skirt 90 furled until the skirt is advanced from within the guide lumen
sufficiently
to enable the skirt to unfurl. If a skirt is provided on distal portion 158,
another
sleeve would likely be provided to keep that skirt furled until catheter 154
is
disposed at a desired position to administer fluid into the body lumen.
Because of
the relatively short length of distal portion 158, catheter 152 can be shorter
and
still enable catheter 154 to be positioned where desired. It will be apparent
that
additional catheters can be included in mufti-cannula catheter assembly 150,
by
providing an additional guide lumen on the distal portion of catheter 154 for
each
added catheter, or by providing multiple catheters like catheter 154, each
having a
distal portion 158 threaded over catheter 152 and disposed at a different
position
along it.
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Obstructive Skirt for Preventing Fluid Flow Past a Catheter
FIGURES 4 and 9 illustrate an embodiment of a skirt 100 used for
preventing or substantially reducing fluid flow past inner catheter 22. While
each
of the following embodiments of such a skirt are illustrated disposed
proximate
the distal end of inner catheter 22, it will be understood that each
embodiment of
the skirt can be included on outer catheter 24, or on distal portion 158 of
catheter 154, or on a single catheter that is not part of a mufti-cannula
catheter
system.
Although the different embodiments of the skirt illustrated and discussed
below have substantially different physical configurations, they are each
generically referred to herein and in the claims that follow as a "skirt,"
since the
function and purpose of these embodiments are substantially identical
regardless
of the configuration of the embodiment. Each skirt has two states, referred to
herein as "furled" and "unfurled," respectively. When a skirt is furled, it
has a
relatively smaller radial extent, being fitted relatively compactly about the
outer
surface of the catheter to which it is attached. In contrast, when a skirt is
unfurled,
the radial extent of the skirt is substantially greater than when furled,
enabling a
distal end of the skirt or some other portion of the skirt to come into
contact with
an inner surface of the body lumen in which the catheter has been inserted.
The function or purpose of the skirt, when unfurled, is to at least partially
block the flow of a bodily fluid through the body lumen in which the catheter
and
skirt are disposed. By threading the catheter through the body lumen while the
skirt is furled, it is possible to more readily advance the portion of the
catheter on
which the skirt is attached through the body lumen without causing any damage
to
the inner surface of the body lumen or to the skirt.
The most common body lumen in which a catheter is used is a blood
vessel, although it should be emphasized that the catheter can be used in
other
types of body lumens that are not blood vessels. Accordingly, when a catheter
with a skirt in accord with the present invention is advanced through a blood
vessel with the skirt furled, it may be preferable to interrupt the flow of
blood
through the vessel by applying a standard pressure cuff to a limb of the
patient in
which the blood vessel extends, as is well known to those of ordinary skill in
the
medical arts. The pressure cuff applies pressure to the blood vessel,
preventing
the blood from flowing in a direction opposite that to which the catheter and
skirt
is advanced through the vessel with the skirt in its furled state. In
addition,
application of the pressure cuff causes venous valves, if present, to relax in
an
open position, facilitating easy passage of the catheter through a vein and
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minimizing risk of trauma to venous valves. Once the catheter has been
advanced
to a desired position, i.e., with the distal port of the catheter disposed at
a site
within the body lumen, the skirt is selectively unfurled. When used in a blood
vessel, after the skirt is unfurled, the pressure cuff is released to allow
blood to
again flow within the blood vessel, but flow of the blood past the unfurled
skirt is
prevented or minimized, since the skirt effectively obstructs (or at least
partially
obstructs) the blood vessel, preventing most of the blood from flowing past
the
position on the catheter at which the skirt is disposed.
The skirt is normally disposed behind the distal port on the catheter to
which the skirt is attached. Therefore, it will be apparent that
administration of a
medicinal fluid or other liquid into the body lumen through the distal port
while
the skirt is unfurled will prevent blood or other bodily fluids from washing
the
fluid away from the site to which it has thus been administered. By increasing
the
residency time of a therapeutic agent or other medicinal fluid administered
through the distal port, the effectiveness of the agent or medicinal fluid at
that site
can be greatly enhanced, in contrast with the case in which the blood is
flowing
past the catheter without any obstruction. The diluting effect of a bodily
fluid
such as blood is minimized by obstructing the flow of the bodily fluid past
the
catheter.
In addition, a therapeutic agent of other medicinal fluid infused under
pressure in the retrograde direction through the catheter into the body lumen
reaches body tissue that is otherwise not accessible. Also, the
microvasculature of
diseased tissue has greater permeability characteristics to take up and
perfuse a
therapeutic agent or medicinal fluid that is delivered in the retrograde
direction
through the body lumen. The unfurled skirt ensures that the therapeutic agent
or
medicinal fluid is infused through the body lumen in the retrograde direction,
which may be important in treating diseased and/or ischemic tissue.
Further details of skirt 100 are illustrated in FIGURE 9. In this particular
embodiment, skirt 100 is fabricated from a relatively thin-walled polymer
material
that is "welded," adhesively bonded, shrink affixed, or otherwise mounted over
distal portion 42 of the catheter. Suitable materials for use in fabricating
this and
other thin-walled skirts described below include polyethylene terephthalate
(PET),
fluoropolymer, NYLONTM, urethane, or PVC plastics. Skirt 100 is formed to
have a generally conical shape when unfurled, as shown in FIGURE 9. To
provide a biasing force that causes skirt 100 to change from its furled state
to its
unfurled state, a plurality of thin metal rods or bars 104 are bonded to the
inner
surface of skirt 100. The metal rods or bars are made of stainless steel,
corrosion
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resistant spring steel, or super-elastic metal, such as Nitinol, or
alternatively, may
be formed of an elastomeric polymer. These rods or bars create a spring
biasing
force directed radially outward so as to cause skirt 100 to assume a generally
conical shape. The relatively wider diameter or radius of skirt 100 at its
distal end
brings it into contact with an internal surface of the body lumen in which the
catheter is inserted. Flow of bodily fluids such as blood past skirt 100 is
prevented by the unfurled state of skirt 100 blocking fluid flow through the
body
lumen, as will be evident from an exemplary application of a skirt discussed
below. Other embodiments of a skirt having a generally conical shape are
illustrated in FIGURES 5-8. In FIGURES 5 and 6, a skirt 74 having a conical
portion 76 that extends radially outward from the surface of the catheter on
which
it is mounted is illustrated. In this case, the polymeric material from which
the
skirt is fabricated has an inherent elastomeric bias that provides a radially
outward
directed forced tending to cause the skirt to change from its furled to
unfurled
state so that the distal end of conical portion 76 contacts the inner surface
of the
body lumen. To minimize the risk of skirt 74 suffering a prolapse or
inversion, a
plurality of tethers 80 extend distally of skirt 74 and are bonded to the
outer
surface of the catheter.
Alternatively, as shown in FIGURES 7 and 8, a skirt 90 having a conical
portion 92 may be formed to include integral tethers 94 that are coupled
distally to
the outer surface of the catheter and define relatively large openings 96
between
adjacent tethers 94 as shown in FIGURES 7 and 8. Skirt 90 is also shown in
FIGURE 16.
With reference to FIGURE 11, yet another skirt 120 is illustrated having a
conical portion 122 that is expanded radially outward by a helical internal
coil
spring 124 when allowed to unfurl. The helical internal coil spring extends
between different sections of distal portion 42 of the catheter and can be
fabricated from stainless steel or spring steel, Nitinol, or a suitable
elastomeric
polymer. Fluid can readily exit the distal portion of the catheter through the
coils
of helical spring 124. When skirt 120 is furled, the coils of helical spring
124
assume a smaller diameter configuration with skirt 120 furled around the outer
surface of the helical spring and catheter.
Another embodiment of a skirt 110 also has a conical section 112 when
unfurled. However, instead of using a spring force to bias the skirt into its
unfurled state, it comprises a Malecot type structure that is selectively
urged to its
unfurled state by a user pulling a proximal end of a line 118 that is coupled
to
relatively stiff struts 114 and extends beyond the proximal end of the
catheter.
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Struts 114 extend from the distal edge of conical-shaped portion 112 and into
slots 116 that are spaced apart around a lumen of the catheter through which
line 118 extends. The line may be fabricated from adhesively-bonded fibers of
polyethylene, or other suitable thin, high-tensile strength material such as
KEVLARTM, polycarbonate, polyether sulfone, polyetheretherketone (PEEK), or
aligned PET. When line 118 is pulled proximally, struts 114 are forced
radially
outward, thereby unfurling conical portion 112 of skirt 110 into contact with
the
inner surface of the body lumen in which the catheter has been inserted. It
should
be noted that this particular construction for skirt 110 will apply a small
dilating
force onto the inner surface of the body lumen or blood vessel, depending upon
the amount of tension exerted on line 118. Fluid can flow through slots 116
into
the body lumen from the internal lumen through which line 118 extends. It
should
be noted that the embodiment of skirt 110 shown in FIGURE 10 is useful in the
multi-cannula catheter assembly only upon the inner catheter, or the innermost
catheter of an assembly having more than two catheters.
FIGURES 12 and 13 illustrate two further embodiments for the skirt. In
FIGURE 12, a skirt 130 generally has a shape like a lily when unfurled. The
thin
polymer material from which the skin is fabricated includes a supporting rib
132
formed of a metallic wire or appropriate polymer plastic extending around its
outer edge. When unfurled, skirt 130 tries to assume the shape shown in
FIGURE 12 and thereby readily adapts to the interior cross-sectional dimension
of
a body lumen such as a blood vessel, sealing against the interior surface of
the
body lumen to partially obstruct flow of fluid therethrough. This skirt
embodiment tends not to dilate the body lumen in which it is used, since any
outward force delivered by rib 132 will not be directed radially, in a
concentric
direction.
In FIGURE 13, a skirt 140 is illustrated in its "unfurled" state, a dash
line 142 indicating the furled radial extent of skirt 140. Skirt 140 can be
fabricated from silicone or other elastic materials that can be deployed
without the
influence of any surrounding fluid pressure. This embodiment tends to cause
minimal dilation of the body lumen with which it is in contact, due to its
relatively
moderate radially directed elastic force.
Referring back to FIGURE 6, an advantage of employing conical-shaped
skirt 74 will be evident. If one or more distal ports 82 are provided in the
wall of
the catheter in the portion of the catheter encompassed by conical portion 76
(or
by corresponding conical portions of the other embodiments discussed above),
it
will be apparent that fluid exiting through distal ports 82 will impinge
directly on
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the inner surface of the conical portion of the skirt and not on the inner
surface of
the body lumen. Thus, possibility of damage due to the force of the fluid
impinging upon the inner surface of the body lumen is substantially reduced.
Turning again to FIGURE 16 in which mufti-cannula catheter
assembly 150 is shown, it will be noted that skirt 90 is included on the
distal
portion of catheter 152. When catheter 152 is initially inserted into a body
lumen,
such as a blood vessel, skirt 90 will be furled within distal portion 158 of
catheter 154. Once distal port 44 of catheter 150 has been advanced to a
desired
site within the body lumen, catheter 154 will be drawn back relative to
catheter 152, enabling skirt 90 to unfurl, bringing conical portion 92 of the
skirt
into contact with the interior surface of the body lumen to obstruct the flow
of
bodily fluid, e.g., blood, past the catheter. If a skirt is included on distal
portion 158 of catheter 154, a sleeve (not shown in this Figure) or other
retainer
will be required to maintain the skirt in its furled state until distal port
162 has
been positioned at the site where fluid will be administered to the body
lumen.
The sleeve can then be withdrawn from the skirt to enable it to unfurl into
sealing
contact with the interior surface of the body lumen and will preferably be
designed to split near side tube 48 upon removal from the patient's body.
Exemplary Application of the Present Invention
FIGURE 14 illustrates how a mufti-cannula catheter assembly 161 that is
provided with a skirt 100 around both an inner catheter 164 and an outer
catheter 163 is advanced through a blood vessel 151 with both of the skirts in
a
furled state. In an illustrative application of the present invention, it is
used for
treating both vascular disease and ischemic tissue of a patient's lower limb
and
providing treatment of an infected ulcer in the patient's foot due to poor
circulation caused by some form of metabolic or vascular disease or associated
complications of these diseases. Mufti-cannula catheter assembly 161 is
inserted
into blood vessel 151 through an introducer after blood flow through the blood
vessel has been impeded by a pressure cuff (not shown) applied to the
patient's
leg. When the pressure cuff is inflated, the physiological valves in the veins
of the
leg will relax in the open position, and blood flow through the vein in which
the
mufti-cannula catheter assembly is inserted will be substantially reduced.
Using a
standard percutaneous access procedure, a guide wire is threaded in retrograde
fashion across valves in the vein and advanced to a site of the intended
treatment
in the foot. The mufti-cannula catheter assembly is advanced coaxially over
the
guide wire to the furthest distal treatment site in the foot.
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In FIGURES 14 and 15, the arrow at the left-hand side of the blood vessel
indicates the normal direction of blood flow through the vessel. To maintain
skirt 100 in its furled state around inner catheter 164, the inner catheter is
positioned with conical portion 102 of the skirt substantially within a distal
opening 168 of a distal end 166 of the outer catheter. The overlying portion
of
distal end 166 on the outer catheter maintains conical portion 102 of skirt
100
furled so long as the inner catheter is substantially contained within the
guide
lumen of outer catheter 163. Skirt 100 on outer catheter 163 is retained in
its
furled state by use of a sleeve 170 that is slipped over the skirt, generally
retaining
conical portion 102 of the skirt against the outer surface of outer catheter
163.
Sleeve 170 can be sufficiently long to extend proximally outside the patient's
body, but in this embodiment is connected to a line 174 where the line is
fused to
the sleeve at a point 172. Line 174 extends back into outer catheter 163 and
through one of the lumens of the outer catheter to a point outside the
patient's
body. Thus, the mufti-cannula catheter assembly is advanced through blood
vessel 151 over the guide wire so as to bring distal port 44 of inner catheter
164 to
a desired position at the treatment site in the foot, as illustrated in FIGURE
15.
The inner catheter is then held constant at that position while the outer
catheter
and sleeve 170 are drawn back from the inner catheter as a single unit,
enabling
conical portion 102 of skirt 100 on the inner catheter to achieve its furled
state,
bringing the distal portion of skirt 100 into contact with the inner surface
of blood
vessel 151. It should also be noted that although not shown, a sleeve like
sleeve 170 can be provided over a skirt disposed on the inner catheter to keep
that
skirt furled until the sleeve is pulled back from the skirt. Thus, providing a
sleeve
over the skirt on the inner catheter is an alternative to using the outer
catheter to
keep the skirt on the inner catheter furled.
From the disposition illustrated in FIGURE 15, the outer catheter and
sleeve 170 are then drawn back over the inner catheter to the site at the mid-
calf in
the patient's leg, for example, where vascular disease has occurred in
adjacent
tissue and is impeding blood flow to the foot, which may be a causative factor
in
causing the infected foot ulcer. This position is where the fluid is to be
administered through distal port 168 on the outer catheter. Once this position
is
achieved, line 174 is drawn back, pulling sleeve 170 away from skirt 100 on
the
outer catheter, enabling the conical portion of the skirt to come into contact
with
the inner surface of blood vessel 151 to prevent any further blood flow past
that
point within the blood vessel.
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At this time, the pressure cuff can be released, allowing blood to flow
through the blood vessel up to skirt 100 on the inner catheter. Different
medicinal
fluids can then be separately infused into blood vessel 151 through distal
ports 44
and 168, respectively, to administer the fluid to the sites in the foot and in
the
mid-calf of the leg. For example, an antibiotic can be administered to distal
port 44 through the inner catheter to treat the infected foot ulcer, while an
appropriate drug is delivered through distal port 168 in outer catheter 163 to
treat
the vascular disease in the adjacent diseased and/or ischemic tissue. Another
lumen in the inner and/or outer catheters can be used for infusing other
fluids,
such as genetically modified agents or growth factor into same of other
treatment
sites to aid in the revascularization of the foot and/or leg or to enhance the
healing
factors at the different treatment sites. It should be noted that the infusion
of fluid
through the outer catheter into the vein within the mid-calf, in this example,
appears to be conveyed through intervening tissue in retrograde flow to reach
the
diseased vasculature in the adjacent tissue. The unfurled skirts increase the
residence time of the medicinal fluids that are infused to encourage such
microcirculatory migration of the medicinal fluids.
After use of the catheter has been completed, the inner catheter is drawn
back through blood vessel 1 S 1 until sleeve 100 on the inner catheter is
encompassed within distal port 168, again causing sleeve 100 on the inner
catheter
to be furled within the outer catheter. In contrast, sleeve 100 on outer
catheter 163
is not furled, but instead, is drawn back through the blood vessel in its
furled state,
since sleeve 170 cannot be readily forced back over skirt 100 on the outer
catheter.
In the event that the skirt on the outer catheter is not required, it should
be
noted that skirt 100 on the inner catheter can be again drawn back into distal
port 168 on the outer catheter to furl the skirt, thereby enabling the mufti-
cannula
catheter assembly to be repositioned to a different site within blood vessel
151.
Once the new position for the distal port of the inner catheter is achieved,
the
outer catheter can again be drawn back from the skirt, enabling the skirt on
the
inner catheter to unfurl and obstruct blood flow through blood vessel 151. It
should be noted that when blood flow through blood vessel 151 is interrupted
by
application of the pressure cuff to the leg, the natural physiological valves
176
within the blood vessel tend to open and thus provide little resistance to the
passage of the various elements of the mufti-cannula catheter assembly through
the blood vessel (vein).
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There are several advantages to a mufti-cannula catheter assembly in
accord with the present invention. It is possible to deliver medical agents or
fluids
in veins, avoiding the need to cross arterial diseased sites with the catheter
tip.
Further, the fluids can be delivered through the distal ports of the different
catheters even though ischemic degradation of an artery has caused circulation
to
be substantially reduced in the veins that convey blood back to the heart. The
obstructive skirts can be deployed and then again furled, leaving no sharp
edges
exposed, producing a low-profile cross section for the catheter assembly when
it is
necessary to move it within the body lumen. It is unnecessary to provide an
inner
lumen on the catheter assembly to convey an inflation fluid to deploy an
obstructive element such as a balloon, as in prior art devices. Most of the
embodiments for the skirt discussed above do not cause dilation of the body
lumen and are not abrasive to the endothelial layer within a blood vessel or
other
body lumen, thereby minimizing the risk of damage to the vessel and reducing
the
likelihood of thrombus formation. Also, since the skirts are generally
conformal,
they do not require sizing for different applications to minimize the risk of
vessel
dilation.
Although the present invention has been described in connection with the
preferred form of practicing it, those of ordinary skill in the art will
understand
that many modifications can be made thereto within the scope of the claims
that
follow. Accordingly, it is not intended that the scope of the invention in any
way
be limited by the above description, but instead be determined entirely by
reference to the claims that follow.
