U.S. patent application number 09/823805 was filed with the patent office on 2002-01-17 for method and systems for establishing vascular access.
Invention is credited to Beathard, Gerald, Brugger, James, Buffaloe, George, Burbank, Jeffrey, Finch, Charles.
Application Number | 20020007158 09/823805 |
Document ID | / |
Family ID | 26712828 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020007158 |
Kind Code |
A1 |
Burbank, Jeffrey ; et
al. |
January 17, 2002 |
Method and systems for establishing vascular access
Abstract
A body lumen access system comprises a distal access cannula and
a proximal access cannula. The distal access cannula is attached to
or within the body lumen and the proximal access cannula is
attached to an implantable port or is transcutaneously positioned
and attached to a luer or other external connector. The distal and
proximal access cannulas are usually implanted separately, cut to
length, and attached at a subcutaneous junction location.
Preferably, the proximal access cannula has a larger lumen diameter
than that of the distal access cannula in order to reduce flow
resistance within the cannula system. In some cases the distal and
proximal access cannulas may be formed integrally.
Inventors: |
Burbank, Jeffrey; (Boxford,
MA) ; Brugger, James; (Newburyport, MA) ;
Finch, Charles; (Clinton, MS) ; Beathard, Gerald;
(Austin, TX) ; Buffaloe, George; (Arvada,
CO) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Family ID: |
26712828 |
Appl. No.: |
09/823805 |
Filed: |
March 30, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09823805 |
Mar 30, 2001 |
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09333728 |
Jun 15, 1999 |
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6238369 |
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09333728 |
Jun 15, 1999 |
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08856641 |
May 15, 1997 |
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5931829 |
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60036124 |
Jan 21, 1997 |
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Current U.S.
Class: |
604/288.03 |
Current CPC
Class: |
A61M 2205/195 20130101;
A61M 5/158 20130101; A61M 39/0208 20130101; A61M 2005/1581
20130101; A61M 1/3653 20130101; A61M 25/0023 20130101; A61M 1/3659
20140204 |
Class at
Publication: |
604/288.03 |
International
Class: |
A61M 037/00 |
Claims
What is claimed is:
1. An implantable connector comprising a tubular body having a
first attachment aperture adapted to receive a first access
cannula, a second attachment aperture adapted to receive a second
access cannula, and a lumen therebetween, wherein the tubular body
is bent so that the first and second attachment apertures are
disposed at a relative angle in the range from 45.degree. to
270.degree..
2. An implantable connector as in claim 1, wherein the relative
angle is in the range from 90.degree. to 180.degree..
3. An implantable connector as in claim 1, further comprising a web
disposed between the first and second attachment apertures.
4. An implantable connector as in claim 1, wherein the lumen has a
diameter in the range from 1 mm to 10 mm.
5. An implantable connector as in claim 4, wherein the first
aperture has a diameter which is larger than that of the second
aperture.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a divisional patent application
of Ser. No. 09/333,728 filed Jun. 15, 1999, which was a divisional
application of Ser. No. 08/865,641, filed May 15, 1997, which
claimed the benefit of Provisional Application Ser. No. 60/036,124,
filed on Jan. 21, 1997, the full disclosures of which are
incorporated herein by reference.
1. FIELD OF THE INVENTION
[0002] The present invention relates generally to the design and
use of medical devices, and more particularly to a method and
system for establishing temporary access to a patient's vascular
system for hemodialysis and other extracorporeal blood
treatments.
[0003] Access to a patient's vascular system can be established by
a variety of temporary and permanently implanted devices. Most
simply, temporary access can be provided by the direct percutaneous
introduction of a needle through the patient's skin and into a
blood vessel. While such a direct approach is relatively simple and
suitable for applications which are limited in time, such as
intravenous feeding, intravenous drug delivery, and the like, they
are not suitable for hemodialysis and other extracorporeal
procedures that must be repeated periodically, often for the
lifetime of the patient.
[0004] For hemodialysis and other extracorporeal treatment
regimens, a variety of transcutaneous catheters and implantable
ports have been proposed over the years. Transcutaneous catheters,
such as the Tesio catheter available from Med Comp and the
Perm-Cath.TM. available from Quinton, comprise a single catheter
tube having a distal end placed in a vein in an in-dwelling manner
and a proximal end which extends through the skin and is which
available for connection to a hemodialysis or other blood treatment
system. Such catheter includes a DACRON.RTM. cuff disposed just
beneath the skin in order to reduce the risk of infection.
[0005] Implantable ports, in contrast, are entirely subcutaneous
and connected to a vein or an artery by a subcutaneous cannula.
Access to the port is achieved by percutaneous placement of a
needle or other connecting tube. Such ports typically comprise a
needle-penetrable septum to permit percutaneous penetration of the
needle. Recently, several valved-port designs have been proposed,
where introduction of a needle or other access tube opens the valve
to provide flow to the cannula which connects to the blood
vessel.
[0006] Both the transcutaneous and implanted port vascular access
systems suffer from certain disadvantages and limitations. For
example, both such access systems permit only limited blood flow
rates. In the case of transcutaneous catheters, the limited flow
rates result from the generally small lumen diameters available in
in-dwelling venous catheters. In the case of implanted port access
systems, the limited flow rates have resulted from both the port
structures and the relatively small lumen diameters available in
the cannulas which connect the port to the blood vessel. Such
limited blood flow rates are problematic since they prolong the
duration of the associated extracorporeal blood treatment protocol,
such as hemodialysis, hemofiltration, and apheresis.
[0007] The initial implantation of both the transcutaneous and
implanted port vascular access systems has also been problematic.
Such systems generally comprise a single catheter or cannula which
is connected to or implanted within the blood vessel and brought to
the external attachment point, i.e. either the implanted port or
transcutaneous tract through the skin. The subcutaneous placement
of the catheter or cannula is difficult in a number of respects.
For example, catheters and cannulas having their distal ends
implanted in the jugular vein are typically bent by an angle from
90.degree. to 180.degree. to locate their associated ports or
catheter exit points at an appropriate location on the patient's
chest. Such bends also can accommodate excess length in the
connecting catheters and cannulas. The bends, however, are also
subject to kinking and other problems. Thus, it would be desirable
to provide methods and systems for implanting vascular access
catheters and cannulas which can accommodate different patient
characteristics and placement patterns.
[0008] An even more significant problem with prior transcutaneous
and implanted port vascular access systems has been replacement. It
is often necessary to replace a transcutaneous catheter when its
distal end becomes dysfunctional due to plugging or other causes.
Heretofore, it has usually been necessary to remove the entire
catheter, including the subcutaneous cuff which has become ingrown
in the tissue. In the case of implanted port systems, either the
port or the cannula attached to the blood vessel could become
dysfunctional. Heretofore, it has generally been necessary to
remove both the port and the implanted cannula when either needs to
be replaced. It would therefore be desirable to provide improved
methods and systems which permit only a portion of the implanted
system to be replaced when other portions of the system remain
functional.
[0009] For these reasons it would be desirable to provide improved
transcutaneous and implanted port access systems and methods for
their implantation and replacement which would overcome at least
some of the problems described above. In particular, it would be
desirable if the vascular access systems could provide enhanced
flow rates, preferably above at least 200 ml/minute, more
preferably above 500 ml/minute, still more preferably above 600
ml/minute, and even more preferably above 700 ml/minute. Systems
and methods of the present invention should also facilitate both
initial implantation and, if necessary, subsequent replacement of
system components with minimum trauma to the patient. At least some
of these objectives will be met by the different aspects of the
present application described below.
2. DESCRIPTION OF THE BACKGROUND ART
[0010] U.S. Pat. Nos. 5,562,617 and 5,041,098 are exemplary of
implantable systems employing cannulas extending between a port and
a blood vessel for providing extracorporeal circulation. U.S. Pat.
Nos. 5,417,656 and 5,281,199 show implantable ports which are
connected to vascular cannulas via a transition region (FIG. 1A)
and to a multiple branch cannula (FIG. 21). U.S. Pat. No. 4,892,518
shows an implanted port with a transition region extending to a
cannula. U.S. Pat. Nos. 5,234,406 and 5,215,530 show two-piece
catheters having a distal portion which can be placed
percutaneously. The '406 patent discloses a large diameter proxinal
portion to enhance the flow rate of anesthetics to the subarachnoid
region of the spine. U.S. Pat. Nos. 5,203,771 and 4,181,132 show
implantable connectors which provide for percutaneous access to
implanted shunts.
[0011] Related co-pending applications, assigned to the assignee of
the present application, include Ser. No. 08/745,903; 08/724,948;
08/634,634; 08/539,105; and 60/036,124.
[0012] The full disclosures of each of the U.S. patents and
co-pending applications listed above are hereby incorporated herein
by reference.
SUMMARY OF THE INVENTION
[0013] The present invention provides improved methods and systems
for accessing body lumens, particularly blood vessels, but also the
peritoneal cavity, and the like. The systems comprise an access
cannula, usually comprising a distal portion and a proximal
portion, which is implanted from the body lumen to a proximal
access site, typically an implanted port or a transcutaneous access
location catheter. Distal access to the body lumen is effected by
any one of a variety of access devices and techniques, such as
in-dwelling cannulas, cross-tubes (T-catheters), end-to-side
anastomosis, and the like. The methods and the systems of the
present invention are particularly useful in that they both
facilitate initial implantation of the access cannula system and
simplify replacement of all or a portion of the access cannulas
system should such replacement become necessary. The design of the
access cannulas also minimize flow resistance, making the systems
particularly compatible with high volume extracorporeal treatment
protocols, e.g. those with flow rates above 200 ml/minute, usually
above 500 ml/minute, and often above 600 ml/minute, and sometimes
above 700 ml/minute or higher.
[0014] According to a first aspect of the method of the present
invention, access to a body lumen in the patient is established by
implanting a distal access cannula between the body lumen and a
subcutaneous junction location. A proximal access cannula is
implanted between the subcutaneous junction location and a catheter
connection location located at a site remote to the body lumen. The
length of at least one of the distal access cannula and the
proximal access cannula is then adjusted (preferably both are
adjusted, e.g. by cutting) so that the cannulas may be joined with
an appropriate total length between the body lumen and the remote
access site, i.e. neither too long nor too short. The proximal end
of the distal access cannula is then connected to the distal end of
the proximal access cannula, typically using a connector which is
placed therebetween.
[0015] The location of the subcutaneous junction location can be
virtually anywhere between the body lumen and the remote access
site, and need not be on a straight path therebetween. Often, the
access cannula will follow an arcuate or U-shaped path between the
body lumen and the access site, and the subcutaneous junction
location can be anywhere along such a path. In some cases, it may
be desirable to dispose or create the subcutaneous junction
location adjacent to the body lumen, e.g. within 0 cm to 5 cm, in
order to reduce the number of incisions necessary to implant the
total system. By locating the junction region adjacent to the body
lumen, only a single incision and cavity need by made for
connecting the distal access cannula to the body lumen and for
connecting the proximal end of the distal access cannula to the
distal end of the proximal access cannula, typically using the
connectors described in more detail below. In other cases, however,
it will be desirable to locate the subcutaneous junction away from
the body lumen, usually from 5 cm to 50 cm from the body lumen. The
subcutaneous junction location will usually not be adjacent to an
implanted port.
[0016] The adjusting step preferably comprises adjusting the length
of both the distal access cannula and the proximal access cannula.
Adjusting typically comprises cutting the end of the cannula which
will be located at the subcutaneous junction location. The cannula
may be cut before it has been implanted (in which case it must be
accurately sized prior to implantation), but will more usually be
cut after it has been partially implanted and the end to be cut has
been tentatively positioned at the subcutaneous junction
location.
[0017] The distal access cannula implanting step comprises
attaching the distal end of the distal access cannula to the body
lumen in some manner. For example, the distal access cannula may be
in the form of an in-dwelling venous catheter in which case its
distal end is introduced through the blood vessel wall, typically
by a distance of at least 1 cm, usually by 5 cm or more, either
through an incision or through a needle-penetration. Alternatively,
the distal end of the distal access cannula may be in the form of a
cross-tube (T-catheter) which is implanted through an incision in
the blood vessel wall, as described in co-pending application Ser.
Nos. 08/539,105 and 08/724,948, the full disclosures of which are
incorporated herein by reference. As a still further alternative,
the distal end of the distal access cannula may be sutured to the
blood vessel wall via an end-to-side anastomosis, as described in
U.S. Pat. No. 5,562,617, the full disclosure of which is
incorporated herein by reference.
[0018] The proximal access cannula implantation step may also
comprise a number of approaches. For example, the proximal access
cannula may be positioned transcutaneously so that its proximal end
lies permanently outside the patient's body. The proximal end would
then have a standard luer or other fitting for connection to an
external catheter for extracorporeal circulation or other purposes.
The proximal access cannula implanting step may alternatively
comprise subcutaneously implanting a port which is connected to a
proximal end of said cannula. The port will be adapted for
receiving a percutaneous needle or other access tube to permit
connection to an external catheter for extracorporeal circulation
or other purposes. Numerous conventional subcutaneous ports have
been described in the medical and patent literature, but the
present invention is particularly suitable for use with the
high-volume, needle-actuated port described in co-pending
Application Ser. No. 60/036,124, the full disclosure of which is
incorporated herein by reference, from which the present
application is a continuation-in-part.
[0019] The distal access cannula and the proximal access cannula
may have substantially equal lumenal cross-sectional areas,
typically having equal diameters in the range from 1 mm to 10 mm,
usually from 3 mm to 10 mm, but will often have unequal
cross-sectional areas. As described in more detail in connection
with a second aspect of the method of the present invention, it
will often be desirable to provide a larger cross-sectional area in
at least a portion of the proximal access cannula, and optionally
in a portion of the proximal end of the distal access cannula, in
order to reduce the total flow resistance presented by the access
cannula system.
[0020] The connecting step of the method for establishing body
lumen access typically comprises providing an intermediate
connector having a first attachment aperture for attaching a
proximal end of the distal access cannula and a second attachment
aperture for connecting a distal end of the proximal access
cannula. While the respective ends of the distal and proximal
access cannulas could be connected directly, e.g. one or both could
have a connector mounted thereon, it is preferable to provide an
intermediate connector which is capable of attaching a "bare" tube.
In this way, the access cannulas may be cut to their desired
lengths, and the resulting "bare" cut end attached to the
intermediate connector in a convenient manner, typically by placing
over an end of the connector and tying using suture or other
filament.
[0021] The intermediate connectors may be linear, i.e. with a
straight lumen so that the distal and proximal access cannulas are
coaxially aligned at their point of attachment. Alternatively, the
connectors can be non-linear, e.g. with their first and second
attachment apertures disposed at a relative angle in the range from
45.degree. to 270.degree., preferably from 90.degree. to
180.degree., in order to dispose the distal and proximal access
cannulas in a non-linear fashion.
[0022] In a particularly preferred aspect of the present invention,
the remote connectors may be adapted to connect a large diameter
proximal access cannula to a smaller diameter distal access
cannula. In some cases, the connector itself may provide for a
transition in the lumen diameter connecting the two cannulas, but
such a transition is not necessary, and the change of diameter may
be provided within one of the cannulas, preferably the distal
access cannula. Such connectors are particularly useful for
providing the low flow resistance access cannulas described
above.
[0023] According to a second aspect of the method of the present
invention, access between a body lumen and an implanted port is
provided by a subcutaneous access cannula having a lumen
therethrough. Improved low flow resistance access is provided by
implanting a cannula having an enlarged lumen in a region proximal
to the body lumen penetration than at and/or distal to the body
lumen penetration. Typically, for intravascular access, the cannula
lumen will have an inner diameter at and/or distal to the body
lumen wall penetration in the range from 1 mm to 6 mm. By providing
a cannula lumen (inner) diameter proximal to the body lumen
penetration in the range from 3 mm to 10 mm, significantly reduced
flow resistance can be achieved.
[0024] In a third aspect of the method of the present invention,
access to a body lumen in the patient is established by providing
an access cannula having a small diameter distal region and a large
diameter proximal region. The access catheter is implanted so that
the small diameter distal region is connected to or within the body
lumen and with the distal end of the large diameter proximal region
located subcutaneously, usually but not necessarily at a
subcutaneous junction region as described above. The proximal end
of the access cannula is available for connection to an external
catheter by any of the methods described above.
[0025] The small diameter distal region and/or the large diameter
proximal region may have uniform or non-uniform diameters along
their entire lengths. While the diameters of each region will
typically be uniform, in some cases it may be desirable to provide
diameters which increase in the proximal direction, where the
increase can be tapered, stepped, or irregular. In the case of
access catheters which comprise two (or more) pieces, the small
diameter distal region will often correspond to the distal access
cannula described above. Alternatively, the distal access cannula
can itself include the small diameter distal region and expand to
the large diameter proximal region, with the proximal access
cannula also having a large diameter after the subcutaneous
connection.
[0026] In a fourth aspect of the methods of the present invention,
an implanted cannula system may be replaced by separately removing
either a distal portion or a proximal portion thereof. The methods
comprise surgically exposing a portion of the access cannula while
leaving at least one of the distal end (attached to a body lumen)
and the proximal portion unexposed. The access cannula is
disconnected at the site where it has been exposed (typically by
removing one end from a remote connector as described above) and
thereafter replacing one of the distal portion and the proximal
portion while leaving the other in place. The replaced section can
then be connected to the previously implanted section in order to
reestablish access. Typically, the entire distal end of the cannula
will be exposed when it is desired to replace the distal portion.
Alternatively, the entire proximal portion of the cannula may be
exposed when it is desired to replace the proximal portion.
Alternatively, when replacing the proximal portion which is
connected at its proximal end to an implanted port, it may only be
necessary to surgically expose the port and the distal end of the
proximal portion leaving the intermediate portion thereof
subcutaneously implanted.
[0027] The present invention further provides systems for
establishing access to a body lumen in a patient. The systems
comprise a distal access cannula having a distal end, a proximal
end, and a lumen therethrough. The distal end of the distal access
cannula is adapted for connection to the body lumen, by any of the
techniques described above, to provide fluid communication between
the body lumen and the distal cannula lumen. The system further
comprises a proximal access cannula having a distal end, a proximal
end, and a lumen therethrough. The proximal end of the proximal
access cannula is adapted for connection to an external catheter to
provide fluid communication between the catheter and the proximal
cannula lumen. Such external connection can be via a transcutaneous
catheter, an implanted port, or any other conventional means. The
system still further comprises a subcutaneously implantable
connector for directly connecting the proximal end of the distal
catheter to the distal end of the proximal catheter. By "directly"
it is meant that the connector provides for substantially unimpeded
flow therethrough, e.g. an unobstructed flow lumen. One of the
objectives of the system of the present invention is to reduce flow
resistance in the access cannula so the inclusion of flow limiting
or control devices within the connector is contraindicated.
[0028] The connector preferably comprises a body having a first
attachment aperture, a second attachment aperture, and an
unobstructed flow lumen therethrough. Optionally, the first
attachment aperture can branch into a plurality of additional
attachment apertures so that a single proximal access cannula can
be connected to a plurality of distal access cannulas, or vice
versa. The flow lumen(s) through the body may be coaxial or
parallel, but can also be curved or deflected so that the first
attachment aperture and second attachment aperture define an angle
therebetween, typically in the range from 45.degree. to
270.degree., preferably in the range from 90.degree. to
180.degree.. Optionally, the lumen through the connector body may
be flared, tapered, or stepped in one direction or the other in
order to provide a transition from a small diameter at one end to a
larger diameter at the other end.
[0029] The present invention further comprises kits which comprise
a system including a distal access cannula and a proximal access
cannula, such as any of those described above, together with
instructions for use according to the methods described above. The
systems and instructions are incorporated into a sterile or
non-sterile package, such as a pouch, box, tray, or the like. The
instructions may be printed on a package insert (a separate sheet)
and/or may be printed on a portion of the packaging. The kits of
the present invention may further comprise any one of the system
components packaged together with instructions for use of that
component according to a method of the present invention, e.g.
replacement of that component within a previously implanted
system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is an isometric view of a first embodiment of a body
lumen access system constructed in accordance with the principles
of the present invention and comprising an in-dwelling venous
cannula, an implantable port having a proximal access cannula
attached thereto, and a connector for connecting the proximal
access cannula to the indwelling venous cannula.
[0031] FIG. 2 is a detailed view of the connector of FIG. 1, shown
in section.
[0032] FIG. 3 is an isometric view of a second embodiment of a body
lumen access system constructed in accordance with the principles
of the present invention and comprising a distal access cannula
having a cross-tube at its distal end, an implantable port having a
proximal access cannula attached thereto, and a connector for
connecting the distal access cannula to the proximal access
cannula.
[0033] FIG. 3A is a detailed view of the distal end of the distal
access cannula of FIG. 3.
[0034] FIG. 4 is an isometric view of a third embodiment of a body
lumen access system constructed in accordance with the principles
of the present invention and comprising a distal access cannula
having a distal end adapted for connection to a body lumen by an
anastomosis, an implantable port having a proximal access cannula
attached thereto, and a connector for connecting the distal access
cannula to the proximal access cannula.
[0035] FIG. 4A is a detailed view of the distal end of the distal
access cannula of FIG. 4.
[0036] FIG. 5 is an isometric view of a fourth embodiment of a body
lumen access system constructed in accordance with the principles
of the present invention and comprising an in-dwelling venous
cannula, a transcutaneous proximal access cannula, and a connector
for connecting the in-dwelling venous cannula to the transcutaneous
proximal access cannula.
[0037] FIG. 6 illustrates a connector having a 90.degree. bend.
[0038] FIG. 7 illustrates a connector having a 180.degree.
bend.
[0039] FIG. 8 illustrates an implantable port having an integral
proximal cannula and a distal access cannula, wherein both the
proximal cannula and the distal cannula have integral connectors
thereon.
[0040] FIG. 9 illustrates a single-piece access cannula having a
small diameter distal end and a large diameter proximal end,
wherein the proximal end of the proximal portion of the cannula is
attached or attachable to an implantable port.
[0041] FIG. 10 illustrates patient vasculature to which the
implantable access systems of the present invention can be
connected.
[0042] FIGS. 11A and 11B illustrate the subcutaneous implantation
of the access system of FIG. 1 into a patient's jugular vein.
[0043] FIG. 12 illustrates the transcutaneous placement of the
access system of FIG. 5 into a patient's jugular vein.
[0044] FIG. 13 illustrates the use of the connector of FIG. 6 for
implanting the access system of FIG. 1 into a patient's jugular
vein.
[0045] FIG. 14 illustrates the implantation of the access system of
FIG. 3 into a patient's artery and vein.
[0046] FIGS. 15A and 15B illustrate implantation of the access
cannula of FIG. 9 into a patient's jugular vein.
[0047] FIG. 16 illustrates a kit according to the present invention
comprising a body lumen access system together with instructions
for use (IFU) and a package.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
[0048] The present invention provides methods and apparatus for
facilitating percutaneous and transcutaneous access to a body lumen
of a patient. Exemplary body lumens, include blood vessels, the
peritoneal cavity, and the like. The methods are particularly
useful for accessing blood vessels, including both arterial blood
vessels and venous blood vessels. While the remaining description
is directed particularly at blood vessels, it will be appreciated
that the invention applies to all body lumens and cavities where
selective percutaneous access might be desired.
[0049] For percutaneous access, ports are implanted subcutaneously
so that a passage therein lies a short distance beneath the surface
of the patient's skin, typically being within 3 mm to 20 mm of the
skin's surface. An access tube may then be percutaneously inserted
into the passage in the access port in order to provide a
connection to the blood vessel via the access port. For
transcutaneous access, a catheter (usually defining a proximal
access cannula according to the present invention) is implanted
through the patient's skin with a proximal end of the catheter
adapted for connection to an external catheter. In both cases,
access can be provided for a variety of purposes, usually involving
withdrawal of blood, the extracorporeal treatment of the withdrawn
blood, and/or the return of the treated blood to the patient. Such
extracorporeal blood treatment will most often be for hemodialysis,
but can also be for hemofiltration, hemodiafiltration, apheresis,
and the like. In addition to extracorporeal treatment, the access
port of the present invention can be used for perfusing drugs,
fluids, and other materials directly into a patient's circulation
for a variety of purposes.
[0050] Apparatus according to the present invention will comprise
access cannulas, usually but not necessarily including both a
distal access cannula which is connected to or implanted within the
body lumen and a separate proximal access cannula which is
connected to an implanted port or transcutaneously positioned
through the patient's skin. A proximal end of the distal access
cannula is connected or connectable to a distal end of the proximal
access cannula at a subcutaneous junction region, typically by a
connector. The cannulas will typically comprise polymeric tubes
extruded from conventional, biocompatible catheter materials, such
as silicone rubber, polyurethane, and the like. The distal access
cannula will typically have a low profile, particularly when all or
a distal portion thereof is intended for implantation in a venous
lumen. Exemplary distal catheters will have a length in the range
from 5 cm to 45 cm, usually from 10 cm to 30 cm, an outer diameter
in the range from 2 mm to 8 mm, usually from 3 mm to 6 mm, and a
lumen diameter in the range from 1 mm to 6 mm, usually from 2 mm to
5 mm. The proximal access cannula will have a length in the range
from 3 cm to 45 cm, usually from 5 cm to 15 cm, an outer diameter
in the range from 4 mm to 11 mm, usually from 6 mm to 8 mm, and a
lumen diameter in the range from 3 mm to 10 mm, usually from 5 mm
to 7 mm. The access cannulas will usually be tubes having uniform
diameters along their entire lengths, but may have tapered,
stepped, or other variations in diameter, as described previously.
The distal end of the proximal access cannula and proximal end of
the distal access cannula will usually be uniform over a length
sufficient to permit cutting, where the cut end of the cannula will
have identical diameter and other properties so that the cut end
may fit over an attachment aperture on the remote connector, as
described in more detail below.
[0051] As described above, the access cannula comprises at least a
discrete distal portion and a discrete proximal portion, where the
portions are separate and connectable through a connector. In
another aspect of the apparatus of the present invention, the
distal and proximal portions of the access cannula may be formed
integrally with the distal portion having a reduced diameter and
the proximal portion having an enlarged diameter to reduce the
overall flow resistance presented by the access cannula. The
lengths of such catheters can be adjusted by cutting at either the
proximal end or the distal end, but the transition region where the
diameter changes will generally be integrally formed and
unavailable for cutting.
[0052] Referring now to FIG. 1, an access system 10 according to
the present invention comprises a distal access cannula 12, a
proximal access cannula 14, and a connector 16 adapted for
connecting a distal end 18 of the proximal access cannula to a
proximal end 20 of the distal access cannula. The distal access
cannula 12 is in the form of an in-dwelling venous catheter and
includes a plurality of apertures 22 near its distal end to
increase blood inflow or outflow through the cannula. The outer
diameter of the venous access cannula 12 (as least over a distal
portion thereof and usually over its entire length) will typically
be in the range from 2 mm to 8 mm, preferably from 3 mm to 6 mm,
and the lumenal diameter will be in the range from 1 mm to 6 mm,
preferably from 2 mm to 5 mm.
[0053] An implantable port 24 is secured to a proximal end 19 of
the proximal access cannula 14. The port 24 can be integrally or
removably secured to the end 19, both of which are described in
co-pending Application Ser. No. 60/036,124, the full disclosure of
which has been previously incorporated herein by reference. The
port 24 provides for percutaneous access to the access system 10 by
means of a needle or other access tube which is introduced through
the patient's skin into an orifice 26 at the top of the port.
Implantation of the access system 10 will be described in more
detail in connection with FIGS. 11A and 11B below.
[0054] The system 10 of FIG. 1, or any of the other systems and
individual components thereof, may be packaged together with
instructions for use (IFU), as shown in FIG. 16. A conventional
package, which may be a pouch P or any other suitable package, such
as a tray, box, tube, or the like, contains the system 10 with the
different components being optionally held in different, isolated
pockets 200, 202, and 204 in the pouch P. Usually, the system 10
will be sterilized within the package, e.g. by radiation or
ethylene oxide, and the instructions are provided on either the
package itself or a separate printed sheet. The instructions will
set forth any of the aspects of the method of the present invention
described herein.
[0055] Referring now to FIG. 1A, the system 10 may be modified for
use in peritoneal dialysis by substituting a pig-tail catheter 13
for the distal access cannula 12. The pig-tail catheter has a
proximal end 15 adapted to be connected to the connector 16 and a
distal end 17 which is similar in design to a conventional
peritoneal dialysis catheter. The catheter 13 includes a cuff 19
which is implanted in the peritoneal wall, and the proximal end can
be trimmed to join the connector 16 in the same manner as described
below for vascular access.
[0056] Referring now to FIG. 2, the connector 16 comprises a body
30, typically composed of a biocompatible metal or thermoplastic,
such as titanium. The connector body 30 defines a first attachment
aperture 32, typically having a relatively small diameter to
receive the proximal end 20 of the distal access cannula 12 (where
the end 20 may be cut or trimmed prior to connection), and a large
diameter connection aperture 34 adapted to receive the distal end
18 of the proximal access cannula 14 (which also may be cut or
trimmed prior to connection). Each attachment aperture 32 and 34
has a conical portion 36 and 38, respectively, and a reduced
diameter region 40 and 42, respectively, to facilitate attachment
of the tubular ends of the access cannulas. In particular, the
tubular ends, which are typically silicone rubber or other
elastomeric material, are pushed over the conical region and into
the reduced diameter region. Thereafter, the ends of the cannulas
can be tied to the reduced diameter region using suture or other
biocompatible material. A lumen 44 through the connector body 30
can have a uniform diameter along its entire length, usually from 1
mm to 10 mm, or can be tapered to increase in diameter toward the
larger attachment aperture 34 intended to connect to the proximal
access cannula 14.
[0057] Referring now to FIG. 3, a second access system 50
constructed in accordance with the principles of the present
invention comprises a proximal access cannula 14 and connector 16,
generally as described above in connection with the embodiment of
FIG. 1. A distal access cannula 52 generally comprises an axial
tubular body 54 having the dimensions generally set forth above,
but terminating at its distal end in a cross-tube 56 as best
illustrated in FIG. 3A. The cross-tube is in the form of a
T-catheter, described in detail in co-pending application Ser. Nos.
08/539,105 and 08/724,948, the full disclosures of which are
incorporated herein by reference. The cross-tube 56 is intended for
implantation within the lumen of a blood vessel in a minimally
intrusive manner. A valve 58, typically a slit valve, is provided
at the distal end of the tube 54 to inhibit blood flow into the
lumen of tube 54 in the absence of a differential pressure. Thus,
blood flow into the tube will be prevented unless there is a
positive or negative pressure applied through the port 24 in order
to effect the inflow or outflow of blood.
[0058] A third access system 60 constructed in accordance with the
principles of the present invention is illustrated in FIG. 4.
Access system 60 comprises a proximal access cannula 14 and
connector 16, generally as described above in connection with FIG.
1. Distal access cannula 62 comprises a tubular member 64
terminating at its distal end in a suturing cuff 66, generally as
illustrated in FIG. 4A. A membrane 68 having a slit valve therein
is provided to prevent flow into or out of the lumen of tube 64 in
the absence of a differential pressure. Suturing of the distal
access cannula 64 to a blood vessel or other body lumen is
described in U.S. Pat. No. 5,562,617, the full disclosure of which
has previously been incorporated herein by reference.
[0059] A fourth access system 70 constructed in accordance with the
principles of the present invention is illustrated in FIG. 5. The
access system 70 comprises a distal access cannula 12 and connector
16, generally as described above in connection with FIG. 1. A
proximal access cannula 72 is intended for transcutaneous placement
through a patient's skin, as described in more detail in connection
with FIG. 12 below. The proximal access cannula will comprise a
distal end 74 which may be trimmed for connection to the connector
16. The proximal access cannula 72 will preferably comprise a cuff
76 which is intended to be implanted immediately beneath the
patient's skin and to inhibit bacterial contamination through the
cannula, as is generally known for venous in-dwelling catheters. A
standard luer or other connector 78 will be provided at the
proximal end of the access cannula 72 to permit connection to an
external catheter.
[0060] The connector 16 provides a linear attachment of the distal
access cannula to the proximal access cannula. In many cases, it
will be desirable to provide a non-linear connection to facilitate
positioning of the remote access site relative to the body lumen
access site. A connector 80 which provides for a 90.degree.
relative angle between the distal and proximal access cannulas is
illustrated in FIG. 6. The connector 80 comprises a bent tube 82
having a first attachment aperture 84 and a second attachment 86.
As illustrated, the attachment apertures are identical, but they
could easily have different sizes intended for attaching to a
larger proximal access cannula and a smaller distal access cannula.
A second bent connector 90 is illustrated in FIG. 7. Connector 90
is U-shaped and provides for a 180.degree. turn between attachment
aperture 92 and attachment aperture 94. Again, the attachment
apertures 92 and 94 are illustrated as having the same size, but
will frequently different sizes intended to attach different sized
cannulas. The connector 90 also includes a web 96 spanning the
region between adjacent legs of the connector. The web 96 is
intended to prevent tissue ingrowth around the connector, thus
facilitating removal should that become necessary. The web 96 also
provides a relatively large target for a surgeon attempting to
access the connector for replacement of either cannula, with or
without replacement of the connector. Without such a connector,
there is significant risk that the surgeon attempting to access the
subcutaneous junction region where the connector is positioned will
accidentally cut or otherwise damage one of the cannulas which are
composed of a silicone material which can easily be cut.
[0061] A less preferred access system according to the present
invention is illustrated in FIG. 8. This system is described in
co-pending parent Application Ser. No. 60/036,124, the full
disclosure of which has previously been incorporated herein by
reference. Implantable port 24 comprises an integral proximal
access cannula 100 having an integral connector 102 at its distal
end. A distal access cannula 104, which may be in any of the forms
described above, comprises an integral connector 106 at its
proximal end, where the connectors 102 and 106 are intended for
mating. While the assembly illustrate in FIG. 8 provides many of
the advantages described herein above, such as the ability to
provide for a larger lumen diameter in the proximal access cannula
100 and the ability to separately remove and replace either the
proximal access cannula (together with the port 24) or the distal
access cannula 104, it lacks many of the other advantages described
above. In particular, by providing permanently affixed connectors
102 and 106, it is not possible to trim the ends of the cannulas
which need to be connected. Also, the integral connection of the
proximal access cannula 100 to the port 24 would prevent separate
replacement of those two components.
[0062] Referring now to FIG. 9, a sixth access system 110
constructed in accordance with the principles of the present
invention comprises a single-piece access cannula 112 having a
small diameter distal portion 114 and a large diameter proximal
portion 116. The proximal end of the proximal portion 116 is
connected to an implantable port 24, generally as described above,
but could also be fashioned as a transcutaneous catheter. The
distal portion 114 of the access cannula 112 is shown as an
in-dwelling catheter, but could be fashioned as any of the other
distal cannulae described above, including the cross-tube
configuration and the suturing cuff configuration. The access
system 110 will have the advantages of the present invention with
regard to reduced flow resistance, but is less preferred since it
will not have the ability for improved implantation and improved
replacement as described in more detail below.
[0063] The body lumen access systems described above are
particularly suitable for establishing percutaneous and
transcutaneous access to single or multiple locations in the
patient's vasculature, including both the arterial and venous
vasculature. As illustrated in FIG. 10, the arterial and venous
vasculature of patient P in the region immediately surrounding the
heart H includes the jugular vein JV, the subclavian vein SV, the
subclavian artery SA, and the aorta A.
[0064] Referring in particular to FIGS. 11A and 11B, the
implantation of a pair of the access cannula systems of FIG. 1 into
the jugular vein JV will be described. The access cannulas 10 may
be implanted by either a cut-down procedure or by the Seldinger
technique. The cut-down procedure will be described first. After
appropriately preparing and anesthetizing the patient, a small
venotomy is performed at the desired site in the jugular vein JV,
typically from 5 cm to 10 cm above the junction of the superior
vena cava SVC and the right atrium of the heart. The distal tip of
a first distal access cannula 12 is then inserted through the
incision in the vascular wall, as illustrated in FIG. 11A, until it
reaches the junction of the superior vena cava SVC and the right
atrium. A second distal access cannula 12 will be inserted through
the same incision so that its distal tip is located approximately 4
cm above the distal tip of the first cannula, as shown in FIG. 11B.
The positioning of the distal tips of the distal access cannulas 12
is verified by X-ray.
[0065] When using the Seldinger technique, an introducer needle is
penetrated through the wall of the vein at the desired insertion
site. After aspirating to assure proper placement, the syringe is
removed from the needle, and a guidewire inserted through the
needle into the vein. The needle is then withdrawn over the
guidewire, and the cutaneous puncture site enlarged with a scalpel.
A second introducer needle and guidewire are then introduced
through the wall of the vein at a site approximately 3 mm away from
the first. A sheath/dilator is then introduced over each guidewire
into the venous lumen, and one of the dilators and guidewires
removed from one of the sheaths. After irrigating the distal access
cannulas with heparinized saline, the distal tip is introduced
through the available sheath and into the venous lumen until the
tip is positioned at the junction of the superior vena cava SVC and
the right atrium. The second distal access cannula 12 is introduced
through the second sheath in the same fashion. The tips of the two
distal access cannulas 12 are adjusted so that they lie
approximately 4 cm apart, and the position confirmed with
X-ray.
[0066] The placement site for each of the implantable ports 24 is
selected based on a number of criteria. The infraclavicular fossa
is generally satisfactory, but the actual site may vary depending
on the patient characteristics. The implantable port 24 should be
located in an anatomic area that provides for good stability, does
not interfere with patient mobility, create pressure points, or
interfere with clothing. Placement should allow for a proper amount
of overlying cutaneous tissue, with an optimum tissue thickness in
the range from 5 mm to 15 mm. Sufficient space should be available
for placement of two implantable catheters when blood circulation
through a single venous location is to be effected.
[0067] After the port implantation site is selected, a subcutaneous
pocket is formed by a cut-down procedure using blunt dissection.
The pocket should be sufficiently large to accommodate the port 24
and allow positioning of the port away from the incision. After the
pocket is created, a tunnel is created between the pocket and the
venous entry site using a tunneling tool. The distal end 18 of the
proximal access cannula 12 is then trimmed so that it terminates at
the venous entry site with sufficient slack for body movement and
subcutaneous connection. The trimmed distal end of the proximal
access cannula is then placed over the larger attachment aperture
34 on the connector 16, and secured with a suture or other
biocompatible filament within the reduced diameter region 42. After
trimming the proximal end 20 of the distal access cannula 12 to the
proper length, the smaller attachment aperture 32 of the connector
16 is then inserted into the trimmed end. The connector 16 is then
secured to the distal access cannula using a suture or other
biocompatible filament placed over the region 40. The corresponding
port 24 should then be finally positioned within the subcutaneous
pocket, and the base secured to the underlying facia using a
non-absorbable monofilament suture. The incisions can then be
cleaned and closed after verifying the proper positioning and
connection of all system components. The final placement is
illustrated in FIG. 11B.
[0068] The transcutaneous catheter systems 70 can be implanted in
the jugular vein JV in an analogous manner, as illustrated in FIG.
12. Implantation of the distal access cannulas 12 can be identical.
The transcutaneous proximal access cannulas 72 are transcutaneously
positioned and advanced to the venous access site in a manner
analogous to placement of conventional transcutaneous catheters,
except for the fact that they are connected to the connectors 16
after trimming, as generally described above.
[0069] The use of remote connectors 90 for connecting the distal
access cannulas 12 and proximal access cannulas 14 of the system of
FIG. 1 is illustrated in FIG. 13. The connectors 90 facilitate the
reversal in direction between the distal access cannulas 12 and
proximal access cannulas 14. As shown in FIG. 13, the connectors 90
are located at a site remote from both the venous access site and
location of the implantable ports 24. This will generally require
either a larger incision or a third incision. It will be possible
to locate the connectors 90 closer to the venous penetration site
in many instances in order to reduce the size and/or number of
penetrations required.
[0070] Placement of the cannula access systems 50 of FIG. 3 at
separate venous and arterial sites is illustrated in FIG. 14. A
cross-tube connector 56 of a first distal access cannula 54 may be
positioned in the subclavian artery SA, as illustrated with the
connector 16 and proximal access cannula 14 located on the
patient's right side. A second cross-tube 56 may be introduced into
a subclavian vein SV with the connector 16, proximal access cannula
14, and implantable port 24 located on the patient's left side.
Circulation between the subclavian artery SA and subclavian vein SV
may then be established by percutaneous connection to the
implantable ports 24.
[0071] Implantation of single tube access cannulas 110 of FIG. 9 is
illustrated in FIGS. 15A and 15B. The distal portions of the
cannulas 114 may be introduced into the jugular vein JV in a manner
analogous to those described in connection with FIGS. 11A and 11B.
After location of the implantable ports 24, as illustrated in FIG.
15B, passage can be tunneled between the vein and the port
location. The proximal portions 116 of the cannula 110 may then be
subcutaneously positioned between the vein and the port locations,
cut to length, and connected to the ports.
[0072] While the above is a complete description of the preferred
embodiments of the invention, various alternatives, modifications,
and equivalents may be used. Therefore, the above description
should not be taken as limiting the scope of the invention which is
defined by the appended claims.
* * * * *