U.S. patent application number 11/417662 was filed with the patent office on 2006-11-30 for multilumen catheter for minimizing limb ischemia.
Invention is credited to Masoud Beizai, Steven F. Bolling, Ryan Kelly, Shawn O'Leary, Robert Pecor, Laksen Sirimanne, Anthony Viole, Wolfgang Werner.
Application Number | 20060270964 11/417662 |
Document ID | / |
Family ID | 27732810 |
Filed Date | 2006-11-30 |
United States Patent
Application |
20060270964 |
Kind Code |
A1 |
Viole; Anthony ; et
al. |
November 30, 2006 |
Multilumen catheter for minimizing limb ischemia
Abstract
A multilumen catheter that maximizes the blood flow into and out
of the patient's vasculature while also providing for passive
and/or active perfusion of tissue downstream of where the catheter
resides in the vasculature. The inventive catheter comprises a
proximal end, a first distal and a second distal end with first and
second lumens extending from the proximal end to each of these
distal ends to provide for blood circulation within one blood
vessel or between two different blood vessels. The second lumen,
and any additional lumens so desired, may be positioned coaxially
with or radially around the first lumen. Redirecting means is
provided at a distal end of at least one of said lumens for
directing blood in a direction generally opposite of the direction
of flow through said lumen.
Inventors: |
Viole; Anthony; (Foothill
Ranch, CA) ; Sirimanne; Laksen; (Irvine, CA) ;
Bolling; Steven F.; (Ann Arbor, MI) ; O'Leary;
Shawn; (Mission Viejo, CA) ; Pecor; Robert;
(Aliso Viejo, CA) ; Kelly; Ryan; (San Diego,
CA) ; Werner; Wolfgang; (Carlsbad, CA) ;
Beizai; Masoud; (Laguna Hills, CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
27732810 |
Appl. No.: |
11/417662 |
Filed: |
May 3, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10078283 |
Feb 14, 2002 |
|
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11417662 |
May 3, 2006 |
|
|
|
09876281 |
Jun 6, 2001 |
7048680 |
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10078283 |
Feb 14, 2002 |
|
|
|
Current U.S.
Class: |
604/8 |
Current CPC
Class: |
A61M 2025/0037 20130101;
A61M 1/3613 20140204; A61M 25/007 20130101; A61M 1/3659 20140204;
A61M 2025/0025 20130101; A61M 2025/0031 20130101; A61M 25/00
20130101; A61M 1/3653 20130101; A61M 2025/1095 20130101; A61M
25/0071 20130101; A61M 2025/0039 20130101; A61M 60/00 20210101;
A61M 2025/0073 20130101; A61M 25/003 20130101; A61M 60/148
20210101; A61M 25/0068 20130101 |
Class at
Publication: |
604/008 |
International
Class: |
A61M 5/00 20060101
A61M005/00 |
Claims
1. A multilumen catheter for directing the flow of blood through a
patient through a single cannulation site, said catheter
comprising: a catheter body having a proximal end, a first distal
end, and a second distal end, said first distal end extending
distally farther from the proximal end than the second distal end;
a first lumen extending between said first distal end and said
proximal end; a second lumen extending between said second distal
end and said proximal end; and a redirecting tip having a surface
positioned at the distal end of and within one of the first and the
second lumens, the surface configured to redirect substantially all
of the blood flow exiting the lumen in a direction generally
opposite of the direction of flow in the lumen; wherein said second
lumen in fluid communication with said first lumen at the proximal
end.
Description
RELATED APPLICATION
[0001] This application is a divisional of U.S. application Ser.
No. 10/078,283, filed Feb. 14, 2002, which is a
continuation-in-part of U.S. application Ser. No. 09/876,281, filed
Jun. 6, 2001, both of which are incorporated herein in their
entireties by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a multilumen catheter and,
in particular, to multilumen catheters designed to prevent ischemia
in patients when the catheter is positioned within the body.
[0004] 2. Description of the Related Art
[0005] It is often necessary to divert the flow of blood from a
patient's blood vessel back to the same or a different blood vessel
as part of treating a patient suffering from one or more of
numerous health impairments, including cardiovascular disease, such
as congestive heart failure. Although surgical cut-down procedures
can achieve this, percutaneous insertion of catheters has made this
procedure less invasive and therefore less traumatic to the
patient. Still, insertion of a cannula into the circulatory system
can cause complex, and sometimes adverse, reactions within the
body.
[0006] Some of the percutaneous procedures involve removing blood
from the body and subsequently returning it to the body. For
example, dialysis treatment involves first removing blood from the
patient's circulatory system, treating the blood outside of the
body, and then returning the blood to the patient's circulatory
system to perfuse the various tissues and organs. Depending on the
volume of blood flow, cannulae with large carrying capacity may be
necessary. By maximizing the cross-sectional area of the cannula,
the volume of blood that may be removed and/or returned to the
patient's vascular system via the cannula is maximized. One
approach to maximize the cross-sectional area of the cannula
involves using either two single lumen catheters or a multi-lumen
catheter. In a recirculation application, one lumen would function
to withdraw blood and one would function to return blood to the
patient. One problem with using two single lumen catheters is that
it subjects the patient to multiple percutaneous insertion
procedures, which complicates the procedure and increases the
potential for infection and other complications. Therefore, it
would be desirable to have a catheter assembly which could be
inserted into the patient through a single insertion site.
[0007] Multilumen catheters in various forms have been employed for
this purpose. For example, multilumen catheters have been made with
two, three or more lumens to serve various aspiration and infusion
functions, including extracting and returning blood to vessels,
taking blood samples for testing and providing medications to the
patient's vascular system. Simple multilumen catheters have been
made by providing two round catheters of equal or nearly equal
length joined by a web, or thin strip. This approach is described
in U.S. Pat. No. 5,776,111 to Tesio. Other multilumen catheter
designs have a unitary body with at least one septum dividing the
lumens which extend from a proximal to a distal end.
[0008] While multilumen catheters require only a single puncture of
the epidermis, their performance is limited in at least two ways.
For one, the outer perimeter of the multilumen catheter cannot
exceed the inner diameter of the vessel into which it is inserted.
Furthermore, the already limited cross-sectional area must be
divided into at least two lumens, one for withdrawal and one for
return. Thus the carrying capacity of each lumen is further
reduced. To supply the same amount of blood, the velocity and
pressure of the blood in the lumens must increase over what it
would be in the vessel itself. This has the potential to cause
damage to the vessel as blood comes jetting out of the return
lumen. Also, it may put further stress upon blood cells, even
causing hemolysis. Thus, multilumen catheters must be made as large
as possible to carry enough blood at satisfactory conditions.
[0009] Where the size of a catheter approaches the interior size of
a vessel, less and less blood can flow around the catheter. As a
result, limited blood supply reaches tissues and organs located
downstream of the catheter in the vascular system. With
insufficient perfusion, the tissues downstream of the lumen
insertion site suffer from ischemia and become oxygen deprived.
Prolonged oxygen deprivation can lead to tissue damage, as is well
known in the art. Therefore, it would be desirable to have a
multilumen catheter that can maximize cross-sectional area of
withdrawal and return lumens while at the same time providing for
acceptable levels of blood perfusion of tissue downstream of the
catheter insertion site in the vascular system. It would also be
advantageous to have a multilumen catheter that can also remove
blood from one peripheral vessel and return blood to a second
peripheral vessel.
SUMMARY OF THE INVENTION
[0010] Overcoming many if not all of the limitations of the prior
art, the present invention comprises a multilumen catheter for
directing the flow of blood to and from a patient through a single
cannulation site. The catheter comprises a proximal end, a first
distal end and a second distal end. The first distal end extends
farther from the proximal end than the second distal end. A first
lumen extends between the first distal end and the proximal end and
a second lumen extends between the second distal end and the
proximal end. At least one aperture, but preferably a plurality of
apertures may be formed in one of the first or second lumens
positioned near the proximal end so that the aperture permits
active maintenance or enhancement of perfusion of blood to the
patient's vasculature downstream of where the aperture resides in
the vasculature when the catheter is inserted into the patient for
treatment.
[0011] In an alternative embodiment, the multilumen catheter
further comprises a third lumen with distal and proximal ends
configured to be positioned entirely within the patient's vascular
system. This third lumen is configured to permit the passive flow
of blood downstream of the catheter site to maintain or enhance
perfusion.
[0012] In another embodiment, the multilumen catheter also
comprises means for redirecting at least a portion of the blood
flow exiting a lumen of the catheter in a direction generally
opposite of the direction of flow of blood in the catheter. In one
embodiment, the redirecting means is a redirecting tip positioned
at the distal end of one of the lumens. In this embodiment, the
redirecting tip is configured to redirect at least a portion of the
blood flow exiting the lumen in a direction generally opposite of
the direction of flow.
[0013] In one embodiment, a connector formed in the shape of a Y
("Y-connector") is positioned at the proximal end of the multilumen
catheter. One leg of the Y-connector is in fluid communication with
the first lumen and the other leg of the Y-connector is in fluid
communication with the second lumen.
[0014] Preferably, in an application of the present invention, an
outflow conduit of a pumping system is fluidly engaged to one lumen
of the multilumen catheter and an inflow conduit of the same system
is fluidly engaged to the other lumen. The inflow and outflow
conduits are fluidly coupled to a pump so that, when connected to
the patient, the pump circulates blood from one distal end of the
multilumen catheter to the other distal end, and also through at
least one aperture in one of the first or second lumens positioned
near the proximal end. In one application, the multilumen catheter
of the present invention is incorporated into an extracardiac
pumping system for supplementing blood circulation in a patient
without any component thereof being connected to the patient's
heart. Such a system is described in U.S. Pat. Nos. 6,200,260 and
6,299,575, which are incorporated herein by reference. The system
includes, in addition to the multilumen catheter, a pump configured
to pump blood through the patient at subcardiac rates, an inflow
conduit fluidly coupled to the pump to divert blood to the pump
from a first blood vessel, and an outflow conduit fluidly coupled
to the pump to direct blood from the pump to a second blood
vessel.
[0015] Another embodiment of the present invention is an
extracardiac pumping system for supplementing blood circulation
through a patient without any component thereof being connected to
the patient's heart. The extracardiac system comprises a multilumen
catheter that has at least two lumens therethrough. Each lumen has
a distal end configured for insertion into the patient's
vasculature and a proximal end. At least two of the lumens are in
fluid communication with each other at their proximal end. The
extracardiac pumping system also comprises a pump secured within
one of the lumens and configured to pump blood through the patient
at subcardiac volumetric rates. The pump has an average flow rate
that, during normal operation thereof, is substantially below that
of the patient's heart when healthy. The pump can be operated to
pump blood from one location in the patient's vasculature to a
different location in the vasculature while the proximal end of
each lumen resides outside the patient's body.
[0016] The present invention also provides a method for treating a
patient using one of the multilumen catheters of the present
invention. The method comprises the step of inserting the
multilumen catheter described above into the patient at a single
cannulation site of a first blood vessel, locating the catheter
such that a first lumen may be in fluid communication with a second
blood vessel and a second lumen may be in fluid communication with
the first blood vessel, withdrawing blood from one of said blood
vessels through one of the first or said second lumens, and
delivering blood through the other of said first or second lumens
so that blood is delivered upstream and downstream of the
cannulation site.
BRIEF DESCRIPTION OF THE DRAWING
[0017] These and other features and advantages of the invention
will now be described with reference to the drawings, which are
intended to illustrate and not to limit the invention.
[0018] FIG. 1 is a schematic of one embodiment of the present
invention multilumen catheter.
[0019] FIG. 2 is a schematic of an alternative embodiment of the
present invention multilumen catheter.
[0020] FIG. 3 is a schematic of an alternative embodiment of the
present invention multilumen catheter with a distal end comprising
a J-tip configuration.
[0021] FIG. 4 is a schematic of an alternative embodiment of the
present invention multilumen catheter comprising a Y-connector.
[0022] FIG. 5 is a schematic of one application of one embodiment
of the multilumen catheter to a patient.
[0023] FIG. 6 is an enlarged view of a portion of the proximal end
of the embodiment shown in FIG. 1 applied to a patient.
[0024] FIG. 7 is an enlarged view of a portion of the proximal end
of the embodiment shown in FIG. 2 applied to a patient.
[0025] FIG. 8 is a schematic of an alternative embodiment of the
present invention multilumen catheter having a redirecting tip.
[0026] FIG. 9 is a schematic of an alternative embodiment of the
present invention multilumen catheter having coaxial lumens.
[0027] FIG. 10 is a cross-sectional view of the embodiment of FIG.
9.
[0028] FIG. 11 is a schematic of an alternative embodiment of the
present invention multilumen catheter having a second lumen and a
third lumen radially housed around a first lumen.
[0029] FIG. 12 is a cross-sectional view of the embodiment of FIG.
11.
[0030] FIG. 13 is a schematic of an extracardiac pumping system for
supplementing blood circulation through a patient.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] Turning now to the drawings provided herein, a more detailed
description of the embodiments of the present invention is provided
below.
[0032] With reference to FIG. 1, one embodiment of the present
invention comprises a multilumen catheter 10 designed to lessen
ischemia that can occur when a large diameter catheter is inserted
into a patient's blood vessel. The multilumen catheter preferably
is of unitary construction and requires only one entry point into
the patient's body. The multilumen catheter 10 comprises at least
two lumens: a first lumen 12 and a second lumen 14. The first lumen
12 extends from a proximal end 16 of the multilumen catheter 10 to
a first distal end 18. The second lumen 14 extends from the
proximal end 16 of the multilumen catheter 10 to a second distal
end 20. The lumens 12, 14 of the multilumen catheter 10 may be
arranged one of many different ways. For example, the two lumens
may be joined in a side-by-side manner, forming a "figure-8" when
viewed from the proximal end 16. Alternately, a single cylindrical
catheter housing may contain within it two or more side-by-side
lumens. A cylindrical catheter housing could be formed with a
diametral septum, i.e. a wall, extending across the cylinder at a
diameter. A cylindrical housing with concentrically positioned
lumens is also contemplated.
[0033] The first distal end 18 may be formed with one or more
distal apertures 22, although such apertures may also be located in
the second distal end 20. The distal apertures 22 may be positioned
close together or spaced circumferentially around the distal end.
The apertures 22 serve to decrease the pressure drop across the
cannula tip, thereby minimizing damage to vessel walls from jetting
effects. It may also be appropriate to practice methods for
directing blood flow so as to minimize damage to vessel walls from
jetting effects and from the recoil effect on the catheter of blood
exiting a catheter. The present invention may further comprise a
tapered tip 24 at the first distal end 18, which facilitates
insertion and threading of the catheter into the patient. The
present invention may also further comprise a tapered tip 26 at the
second distal end 20.
[0034] One preferred embodiment of the multilumen catheter further
comprises a set of apertures 28 positioned on the catheter 10 near
the proximal end 16. The apertures 28 are formed on at least one
lumen of the catheter to provide for fluid communication between
one of the lumens 12, or 14 of the multilumen catheter 10 and the
blood vessel in which it resides. A radiopaque marker 30 may be
positioned at the distal end 18 of the multilumen catheter 10. The
multilumen catheter could further comprise markings 32 near the
proximal end of the multilumen catheter which are a known distance
from one or more of the distal ends. These markings 32, as well as
the marker 30 can be used to accurately position the catheter when
applied to the patient.
[0035] In another embodiment of the present multilumen catheter
shown in FIG. 2, the multilumen catheter 110 comprises a third
lumen 134 extending between a proximal end 136 and a distal end
138. The lumen 134 is positioned and sized such that when the
multilumen catheter 110 is applied to the patient (described
below), the lumen resides entirely within the patient's body. As
described above, the lumen 134 may be connected to the catheter 110
in a variety of ways. The purpose of the third lumen 134 is
configured to permit the passive flow of blood downstream to the
catheter to enhance perfusion. The embodiment shown in FIG. 2 also
may have apertures 128 disposed near the proximal end 116 of the
multilumen catheter 110. As described above, this embodiment may
further comprise a tapered tip 140 at the distal end of the third
lumen 134 and a tapered tip 142 at the proximal end of the third
lumen 134 to facilitate application of the catheter to the
patient.
[0036] In one variation of the three lumen embodiment the third
lumen 134 may be made of collapsible material. In the collapsed
state, the third lumen 134 would conform to at least a portion of
the outside surface of the multilumen catheter 110. Once applied to
the patient, as described in more detail below, the lumen 134 would
be expanded to the deployed state shown in FIG. 2. This collapsible
lumen could comprise a stone basket, or a frame similar to a stent.
A stone basket is a structure that can be deployed within a
patient's body and is used to capture objects. Here, the basket is
used primarily to create a space between the catheter 110 and the
vessel wall to permit the passive flow of blood downstream of the
catheter site to enhance perfusion.
[0037] In an alternate embodiment of the multilumen catheter 210,
shown in FIG. 3, the first distal end 218 is formed in the shape of
a J-tip. That is, the opening at the distal end 218 may be curved
such that blood exiting the lumen 212 is directed back along the
multilumen catheter 210. Distal aperture(s) 222 may be formed at
the bend of the J-tip so that blood also exits the lumen 212 and
flows distal of the catheter 210. The "J" shape of the multi-lumen
catheter tip may be formed and/or maintained by pre-loading it with
a coil or with wire reinforcement, or by using a shape-memory
material to create and maintain this shape. If the catheter is
inserted so that the tip is straight and the "J" shape is deployed
after the catheter inserted into the patient, the catheter may
comprise a tapered tip at the first distal end 218, as described
above.
[0038] Referring to FIG. 4, yet another alternative embodiment of
the present invention multilumen catheter 310 comprises a
Y-connector 334 formed at the proximal end of the multilumen
catheter 310. As described above, the lumens are separated in any
suitable way such that fluid communication is provided between the
distal end 318 of the lumen 312 of the multilumen catheter 310 and
the proximal end 336 of one leg of the Y-connector 334, and fluid
communication is provided between the distal end 320 of the lumen
314 of the catheter 310 and the proximal end 338 of one leg of the
Y-connector 334.
[0039] Any of the multilumen catheters described herein may be made
from various materials to improve their viability in long-term
treatment applications. For example, it is preferred that the
biocompatibility of the catheter be improved compared to uncoated
catheters to prevent adverse reactions such as compliment
activation and the like. To prevent such side effects, the interior
lumens of the catheters can be coated with biocompatible materials.
Also known in the art are anti-bacterial coatings. Such coatings
may be very useful on the outer surface of the catheter. This is
especially true at or about where the catheter enters the patient's
skin. At such a location, the patient is vulnerable to introduction
of bacteria into the body cavity. Anti-bacterial coatings can
reduce the likelihood of infection and thus improve the viability
of long-term treatments.
[0040] In one application, the multilumen catheter of the present
invention may be integrated into a pumping system, such as the one
described in more detail in U.S. Pat. No. 6,200,260. Referring to
FIG. 5, such a system comprises the multilumen catheter 10, an
inflow conduit 38, an outflow conduit 40 and a pump 42. One end of
the outflow conduit 40 may be connected to the proximal end of the
lumen 12, while the other end is connected to the inlet of the pump
42. One end of the inflow conduit 38 may be connected to the
proximal end of the lumen 14, while the other end is connected to
the outlet of the pump 42. This results in a flow from the first
distal end 18 to the second distal end 20. Of course, the flow
direction may be reversed using the same multilumen catheter,
resulting in a flow from distal end 20 to distal end 18. In that
case, the outflow conduit 40 is connected to the proximal end of
lumen 14 and the inflow conduit 38 is connected to the proximal end
of lumen 12. Referring to FIG. 5, the present multilumen catheter
10 when incorporated into a pumping system may be applied to a
patient in an arterial-arterial fashion. Where the multilumen
catheter 10 is inserted into the femoral artery 44 of the patient
46. The radiopaque marker 30 which may be incorporated into the
distal end 18 of the multilumen catheter is used to track the
insertion of the catheter so that to catheter may be positioned at
a desired site within the patient's vascular system. As mentioned
above, markings 32 on the proximal end could also be used to locate
the distal end or ends.
[0041] In one example, the distal end 18 may be located in the
aortic arch 48. The pump draws blood from the patient's vascular
system in the area near the distal end 18 and into the lumen 12.
This blood is further drawn into the lumen of the conduit 40 and
into the pump 42. The pump 42 then expels the blood into the lumen
of the outflow conduit 38. This lumen carries the blood into the
lumen 14 of the multilumen catheter 10 and back into the patient's
vascular system in the area near the distal end 20. As described in
greater detail below regarding FIGS. 6 and 7, the apertures 28
and/or the third lumen 134 provide blood flow to the patient's
vasculature downstream of where the multilumen catheter resides in
the vasculature to maintain or enhance perfusion of blood. The
blood flow in the multilumen catheter may be reversed. In that
case, blood is drawn from the patient through distal end 20 and
returned to the patient through distal end 18.
[0042] Referring to FIG. 6, the multilumen catheter 10 comprises
features that will maintain or increase the blood flow to
downstream tissue when the catheter is inserted into the patient.
The apertures 28 provide for fluid communication between at least
one lumen 12 or 14 and the patient
[0043] s blood vessel. The apertures 28, thus, provides active
perfusion of the downstream tissues.
[0044] Referring to FIG. 7, the lumen 134 of the embodiment shown
in FIG. 2 is located entirely within the vessel when the catheter
110 is inserted into the patient. The lumen provides a pathway for
blood flow to tissue downstream of the catheter so that the
catheter 110 may maintain or increase the flow of blood to
downstream tissue. The lumen 134, thus, provides passive perfusion.
If desired, apertures may be included in one of the other two
lumens to supplement passive perfusion with active perfusion.
[0045] Referring to FIG. 8, yet another alternative embodiment of
the present invention is a multilumen catheter 410 for directing
the flow of blood through a patient through a single cannulation
site. The catheter 410 comprises a proximal end 414, a first distal
end 418, and a second distal end 422. The first distal end 418
extends distally farther from the proximal end 414 than does the
second distal end 422. A first lumen 426 extends between the first
distal end 418 and the proximal end 414. A second lumen 430 extends
between the second distal end 422 and the proximal end 414. As with
other embodiments, a radiopaque marker may be provided.
[0046] Means for redirecting the flow of blood out of the catheter
is provided. For example, in the embodiment of FIG. 8, a
redirecting tip 434 is positioned at the distal end of one of the
lumens, in this case first lumen 426. The redirecting tip 434 is
configured to redirect at least a portion of the blood flow exiting
the lumen 426 in a direction generally opposite of the direction of
flow of blood in the lumen 426. One of a variety of configurations
for a redirecting tip may be employed.
[0047] In the embodiment of FIG. 8, the redirecting tip 434 has a
closed end 438 at a distal position that is generally
hemispherially shaped, although it need not be, and may more
particularly have a parabolic profile. Preferably, a plurality of
outlets 442 are provided in the side of the lumen 426 that has the
redirecting tip 434. These outlets 442 permit blood to flow out of
the lumen 426 and into the vasculature of the patient. As shown,
the outlets 442 comprise rectangular windows framed by structural
elements 444 that connect the closed end 438 to the rest of the
catheter 410. It should be recognized that the number and the shape
of the outlets 442 can vary.
[0048] The redirecting tip 434 further comprises a flow redirecting
surface 446 that defines the proximal portion of the closed end 438
and the travel path of the redirected blood. In this embodiment, a
crosssection of the flow redirecting surface 446 taken through the
longitudinal axis of the lumen 426 reflects two parabolic curves
meeting at the longitudinal axis. The three dimensional shape of
the redirecting surface 446 of this embodiment is defined by
rotating one of the parabolic curves about the longitudinal axis of
the lumen 426 in which the surface 446 is positioned. This is one
geometrical shape that could be used to form the redirecting
surface 446 to gradually redirect the flow of the blood exiting the
lumen 426. Other geometrical shapes could be used as well to define
the redirecting surface.
[0049] The J-tip configuration, discussed above is another means
for redirecting blood in a direction generally opposite of the
direction of flow of blood through the lumen 426.
[0050] Referring to FIGS. 9 and 10, a multilumen catheter 510 for
directing the flow of blood through a patient through a single
cannulation site comprises a proximal end 516 a first distal end
518 and a second distal end 520. The first distal end 518 extends
distally farther from the proximal end 516 than the second distal
end 520. A first lumen 522 extends between the first distal end 518
and the proximal end 516. A second lumen 524 extends between the
second distal end 520 and the proximal end 516, is positioned
coaxially with the first lumen 522, and has a diameter greater than
the first lumen 522. A radiopaque marker may be provided if
desired.
[0051] One application of the catheter 510 comprises connecting the
second lumen 524 to a patient's blood vessel, preferably via an
anastomosis connection after the first lumen 522, which is
preferably of tubular configuration, is inserted through the same
vessel. In this application, blood may be drawn through the second
lumen 524 and redirected into the first lumen 522 using a
circulating system such as that disclosed in U.S. Pat. No.
6,200,260. In another application, the first and second lumen may
be inserted in the blood vessel in a manner that results in the
second lumen 524 extending into the vessel. In this application, if
desired, apertures 526 may be provided to permit a more diffuse
discharge of blood into the vessel from second lumen 524.
[0052] Referring to FIGS. 11 and 12, a multilumen catheter 610 for
directing the flow of blood through a patient through a single
cannulation site comprises a proximal end 616, a first distal end
618, and a second distal end 620. The first distal end 618 extends
distally farther from the proximal end 616 than the second distal
end 620. A first lumen 622 extends between the first distal end 618
and the proximal end 616. A second lumen 624, and if desired a
third lumen 626, extend between the second distal end 620 and the
proximal end 616. In one application, the third lumen 626 is in
fluid communication with the second lumen 624 at a position
proximal of the catheter 610, although they need not be. The second
lumen 624 and third lumen 626 are positioned radially around the
first lumen 622 in a housing 628 that surrounds the first lumen
622, as shown in FIG. 12. One variation of the catheter shown in
FIGS. 11 and 12 comprises a fourth lumen in the housing 628 where,
if desired, the fourth lumen may be in fluid communication with
second lumen 624 and/or third lumen 626 proximal of the catheter.
The fourth lumen, as well as the second lumen 624 and the third
lumen 626 can be arranged in any suitable manner within the housing
628. In one embodiment, the lumens are arranged symmetrically and
radially around the first lumen 622. Asymmetrical arrangements are
also contemplated.
[0053] With reference to FIG. 13, another embodiment of the present
invention comprises an extracardiac pumping system 700 for
supplementing blood circulation through a patient without any
component thereof being connected to the patient's heart. The
extracardiac system 700 comprises a multilumen catheter 704 and a
pump 706 housed within the catheter 704.
[0054] The multilumen catheter 704 of the system 700 comprises a
first lumen 708 with a proximal end 710 and a distal end 712. The
catheter 704 also comprises a second lumen 716 with a proximal end
718 and a distal end 720. In other embodiments, the catheter 704
can have additional lumens, as discussed above. The distal ends
712, 720 are configured for insertion into the patient's
vasculature. The two lumens 708, 716 are in fluid communication
with each other at their proximal ends 710, 718. First lumen 708 is
longer than second lumen 716. In other variations, the lumens 708,
716 could be of the same length.
[0055] The pump 706 is secured within one of the lumens 708, 716
and is configured to pump blood through the patient at subcardiac
volumetric rates the benefits of which are discussed in U.S. Pat.
No. 6,200,260. The pump 706 has an average flow rate that, during
normal operation thereof, is substantially below that of the
patient's heart when healthy. The pump 706 may be operated to pump
blood from one location in the patient's vasculature to a different
location in the vasculature while the proximal end 710 of the first
lumen 708 and the proximal end 718 of the second lumen 716 resides
outside the patient's body. If desired, the entire system 700 may
be implanted into a patient's blood vessel.
[0056] If desired, at least one aperture 724 is provided in one of
the lumens, in this case lumen 708 and is positioned in the lumen
distal from the proximal end 710 so that the aperture(s) 724 may
reside within the patient's vasculature, close to the point of
insertion. The aperture 724 can maintain or enhance perfusion of
blood to the patient's vasculature downstream of where the
aperture(s) 724 resides in the vasculature when inserted into the
patient. As discussed above, one or more of the lumens of the
catheter 704 can have a tapered tip 726. Also, at least one
aperture may be positioned proximate a distal end of at least one
of the lumens. In other embodiment, a third lumen could be provided
that is configured similar to, and functions the same as, the third
lumen 134 shown in FIG. 2.
[0057] A variety of redirecting tip constructions can be employed
in different embodiments of the catheter 704 of the extracardiac
pumping system 700, as discussed above; for example redirecting tip
730. Also, the extracardiac pumping system 700 may be provided with
a radiopaque marker 728. As discussed above, the marker 728 can be
used to position the catheter 704 of the extracardiac pumping
system 700 when applied to a patient.
[0058] The invention may be embodied in other specific forms
without departing from its spirit or essential characteristics. The
described embodiment is to be considered in all respects only as
illustrative and not restrictive and the scope of the invention is,
therefore, indicated by the appended claims rather than by the
foregoing description. All changes which come within the meaning
and range of equivalency of the claims are to be embraced within
their scope.
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