U.S. patent application number 11/417658 was filed with the patent office on 2007-05-31 for squitieri hemodialysis and vascular access systems.
Invention is credited to Rafael P. Squitieri.
Application Number | 20070123811 11/417658 |
Document ID | / |
Family ID | 26713805 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070123811 |
Kind Code |
A1 |
Squitieri; Rafael P. |
May 31, 2007 |
Squitieri hemodialysis and vascular access systems
Abstract
A hemodialysis and vascular access system comprises a
subcutaneous composite PTFE silastic arteriovenous fistula having
an indwelling silastic venous end which is inserted percutaneously
into a vein and a PTFE arterial end which is anastomosed to an
artery. Access to a blood stream within the system is gained by
direct puncture of needle(s) into a needle receiving site having a
tubular passage within a metal or plastic frame and a silicone
upper surface through which needle(s) are inserted. In an alternate
embodiment of the invention, percutaneous access to a blood stream
may be gained by placing needles directly into the system (i.e.
into the PTFE arterial end). The invention also proposes an
additional embodiment having an arterialized indwelling venous
catheter where blood flows from an artery through a tube and a port
into an arterial reservoir and is returned to a vein via a port and
a venous outlet tube distinct and distant from the area where the
blood from the artery enters the arterial reservoir. The site where
blood is returned to the vein is not directly fixed to the venous
wall but is free floating within the vein. This system provides a
hemodialysis and venous access graft which has superior longevity
and performance, is easier to implant and is much more user
friendly.
Inventors: |
Squitieri; Rafael P.;
(US) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
26713805 |
Appl. No.: |
11/417658 |
Filed: |
May 3, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10219998 |
Aug 15, 2002 |
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11417658 |
May 3, 2006 |
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08835316 |
Apr 7, 1997 |
6102884 |
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10219998 |
Aug 15, 2002 |
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60037094 |
Feb 3, 1997 |
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Current U.S.
Class: |
604/6.16 |
Current CPC
Class: |
A61M 1/3655 20130101;
A61M 1/3653 20130101; A61M 2039/0211 20130101; A61M 39/0208
20130101; A61M 2005/1581 20130101; A61M 2039/0258 20130101 |
Class at
Publication: |
604/006.16 |
International
Class: |
A61M 37/00 20060101
A61M037/00 |
Claims
1. A hemodialysis and vascular access system wherein: said system
comprises a first portion comprising a tube and a second portion
comprising a catheter and wherein: said tube is provided from a
material which can be sutured to the artery with a first end of
said tube adapted to be coupled to an artery; and said catheter is
adapted to be inserted within a vein at an insertion site, with a
first end of the catheter having an opening adapted to be within
the vein itself and wherein the opening in the first end of said
catheter is distant from the insertion site and said tube and said
catheter being adapted to be entirely subcutaneous in use and
configured to avoid, in use, a reservoir therein.
2. The hemodialysis and vascular access system of claim 1, wherein
said system has a single lumen formed by said tube and said
catheter.
3. The hemodialysis and vascular access system of claim 1, wherein
said first end of the catheter is adapted for percutaneous
insertion.
4. The hemodialysis and vascular access system of claim 3, wherein
said first end of the catheter is beveled.
5. The hemodialysis and vascular access system of claim 1, wherein
a second end of the tube is adapted to be coupled to a second end
of the catheter.
6. The hemodialysis and vascular access system of claim 5, wherein
said second end of the catheter comprises an enlarged portion
configured to lock with said second end of the tube.
7. The hemodialysis and vascular access system of claim 5, wherein
said system further comprises a coupler adapted to join said second
end of the tube to said second end of the catheter.
8. The hemodialysis and vascular access system of claim 5, wherein
said second end of the tube is glued to said second end of the
catheter.
9. The hemodialysis and vascular access system of claim 1, wherein
said catheter comprises a cuff adapted for sewing to the vein.
10. The hemodialysis and vascular access system of claim 1, wherein
said catheter comprises multiple layers of material.
11. The hemodialysis and vascular access system of claim 10,
wherein at least one layer is a thrombus resistant coating.
12. The hemodialysis and vascular access system of claim 10,
wherein said catheter further comprises an inner layer of PTFE
material and an outer layer of silastic material.
13. The hemodialysis and vascular access system of claim 1, wherein
the tube comprises a PTFE material and the catheter comprises a
silastic material.
14. The hemodialysis and vascular access system of claim 1, wherein
said system further comprises a needle receiving site located
between said first end of the tube and said first end of the
catheter.
15. The hemodialysis and vascular access system of claim 14,
wherein the needle receiving site comprises a frame having a
passage extending therethrough, an inlet adapted to connect to said
second end of the tube, and an outlet adapted to connect to a
second end of the catheter.
16. The hemodialysis and vascular access system of claim 1, wherein
said system further comprises at least one needle having a first
end configured to couple to a hemodialysis device and a second end
adapted for insertion directly into said tube.
17. A hemodialysis and vascular access system to shunt blood
between a vein and an artery, said system having a single lumen
comprising: a tube having first and second ends, said first end
adapted to be anastomosed to said artery; and a catheter,
comprising tubing having a first end and a second end, said second
end being connected to said second end of said tube; said catheter
having a site for entering said vein, said site being away from
said first end of said catheter so that, in use, said first end can
be located downstream in said vein; and needle receiving sites
between said first end of said tube and said first end of said
catheter; said tube and said catheter being adapted to be entirely
subcutaneous in use and configured to avoid, in use, a blood
reservoir therein and to provide continuous blood flow.
18. The hemodialysis and vascular access system of claim 17,
wherein said first end of the catheter is adapted for percutaneous
insertion in said vein.
19. The hemodialysis and vascular access system of claim 17,
wherein said first end of the catheter is beveled.
20. The hemodialysis and vascular access system of claims 17,
wherein said second end of the catheter comprises an enlarged
portion configured to lock with said second end of the tube.
21. The hemodialysis and vascular access system of claim 17,
wherein said system further comprises a coupler adapted to join
said second end of the tube to said second end of the catheter.
22. The hemodialysis and vascular access system of claim 17,
wherein said second end of the tube is glued to said second end of
the catheter.
23. The hemodialysis and vascular access system of claims 1,
wherein said catheter comprises a cuff adapted for sewing to the
vein.
24. The hemodialysis and vascular access system of claim 1, wherein
said catheter comprises multiple layers of material.
25. The hemodialysis and vascular access system of claim 24,
wherein at least one layer is a thrombus resistant coating.
26. The hemodialysis and vascular access system of claim 24,
wherein said catheter further comprises an inner layer of PTFE
material and an outer layer of silastic material.
27. The hemodialysis and vascular access system of claim 17,
wherein the material of said tube and said catheter comprise
PTFE.
28. The hemodialysis and vascular access system of claim 17,
wherein the material of said tube is PTFE and the material of said
catheter is silastic.
29. The hemodialysis and vascular access system of claim 17,
further comprising a needle receiving site between said first and
second ends.
30. The hemodialysis and vascular access system of claim 29,
wherein the needle receiving site comprises a frame having a
passage extending therethrough, an inlet adapted to connect to said
first portion of the tube, an outlet adapted to connect to said
second portion of the tube.
31. The hemodialysis and vascular access system of claim 17,
wherein said system further comprises at least one needle having a
first end configured to couple to a hemodialysis device and a
second end adapted for insertion directly into said system.
32. A hemodialysis and vascular access system, comprising: an
arterialized indwelling venous catheter having a first portion
provided from a material which is biocompatible with an arterial
system, has a nonthrombogenic characteristic, which is adapted for
attachment to an arterial system and a catheter section, with a
first end of said first portion adapted to be coupled to an
arterial system and a portion of the catheter section adapted to be
inserted within a venous system at an insertion site, said catheter
section portion having an outside diameter which is less than an
inner diameter of the venous system and having at least one opening
in an end thereof with at least one of the at least one openings in
the catheter section portion adapted to be within the venous system
itself and wherein the at least one opening is distant from the
insertion site such that, in operation, blood flows from the
arterial system through the catheter and is returned to the venous
system through the at least one opening and blood also flows
through the vein uninterrupted around at least an outer portion of
said catheter; and at least one needle having a first end coupled
to a hemodialysis device and having a second end adapted for
insertion directly into the arterialized indwelling venous catheter
to shunt the blood flow through the dialysis device.
33. The hemodialysis and vascular access system of claim 32 wherein
the first portion of said arterialized indwelling venous catheter
is provided from a first tube and said catheter section is provided
from a second tube comprising multiple layers and a first end of
said first tube is coupled to a first end of said second tube.
34. The hemodialysis and vascular access system of claim 33 wherein
said first and second tubes are adapted for percutaneous
placement.
35. The hemodialysis and vascular access system of claim 33 wherein
the end of said second tube which is coupled to the first tube
includes an enlarged portion in which the first end of said first
tube is disposed.
36. A hemodialysis and vascular access system as in claim 32,
wherein the first portion comprises PTFE.
37. A hemodialysis and vascular access system as in claim 32,
wherein the first portion has a diameter of approximately 7 mm.
38. A hemodialysis and vascular access system as in claim 32,
wherein the first end of the first portion has a diameter of about
4 mm.
39. A hemodialysis and vascular access system as in claim 32,
wherein the catheter section comprises a silastic material.
40. A hemodialysis and vascular access system as in claim 32,
wherein the catheter section comprises silicone.
41. A hemodialysis and vascular access system as in claim 32,
wherein a downstream end of the catheter section is provided with a
bevel.
42. A hemodialysis and vascular access system as in claim 32,
additionally comprising an access segment for receiving a needle to
allow access to blood flowing through the catheter.
43. A hemodialysis and vascular access system as in claim 33,
wherein the access segment comprises a self sealing material.
44. A hemodialysis and vascular access system as in claim 43,
wherein the self sealing material comprises silicone.
45. A hemodialysis and vascular access system as in claim 43,
wherein the access segment is removably connected to the access
system.
46. A hemodialysis and vascular access system as in claim 43,
further comprising a frame in the access segment.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/219,998 filed on Aug. 15, 2002, which is a reissue of U.S.
application Ser. No. 08/835,316 filed on Apr. 7, 1997, now U.S.
Pat. No. 6,102,884, which claims benefit under 35 U.S.C. Section
119(e) to U.S. Application No. 60/037,094, filed on Feb. 3, 1997,
all of which are incorporated herein by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] Currently, HD (hemodialysis) and vascular access for
chemotherapy and plasmapheresis is achieved in one of several ways.
Applicant's invention involves a new method and instrumentation for
HD and vascular access designed to eliminate the problems of the
prior methods and create a new, more durable, easier to use,
vascular access system.
[0003] One prior art method involves a primary arteriovenous
fistula. In this method, a native artery is sewn to a native vein
creating a high flow system of blood in a vein which over time can
be accessed with two hemodialysis needles attached to a dialysis
machine. The problem with this method is that few patients are
candidates secondary to anatomy and in others the veins or shunt
fail to enlarge and mature properly even if the primary fistula
remains patent. These arteriovenous fistulas also become aneursymol
over time requiring revision.
[0004] Another method involves a subcutaneous prosthetic conduit
(PTFE) in the shape of a tube which is sewn at either end to
openings made in an artery and vein. This method causes recurrent
stenosis at the venous outflow leading to thrombosis (i.e., graft
closure) secondary to intimal hyperplasia at venous anastomosis.
Thrombosis also occurs at needle puncture sites along the PTFE.
[0005] Another method involves a "tunneled" percutaneous dual lumen
catheter which is inserted into a central vein. This causes
recurrent thrombosis secondary to stasis of blood in the lumen
(i.e., not a continuous flow system like an A-V fistula) and build
up of fibrinous debris at the venous end. Further, the access end
of the catheter protrudes through the skin making it cosmetically
unappealing, cumbersome to live with, as well as more likely to
become infected.
[0006] A further method involves the use of the Sorenson Catheter.
This is a percutaneous (not tunneled) dual lumen catheter, placed
into the central venous system, which is used to provide temporary
access for the purposes of hemodialysis. These catheters are prone
to kinking, clotting, infection, and poor flow rates.
[0007] A still further method of vascular access involves the
"Port-a-cath". This system of venous access, which utilizes a
subcutaneous reservoir attached to a central venous catheter, is
used for long term intervenous access for chemotherapy etc. (It is
not intended for HD.) The ports are prone to clotting and must be
continually flushed since they are a stagnant system.
[0008] Applicant's invention involves a vascular access system,
known as the Squitieri Hemodialysis and Vascular Access System,
which creates a continuous blood flow and which is easily accessed
and resistant to clotting. These advantages provide ideal access
for long term HD chemo or blood draws. An example, would be
patients who are on coumadin which require weekly blood draws. This
new system becomes less painful over time as the skin over the
"needle access" site become less sensitive. The veins are spared
repeated blood draws which results in vein thrombosis to such a
degree that some patients "have no veins left" making routine blood
draws impossible.
[0009] Among the more relevant prior art patents are U.S. Pat. Nos.
4,898,669, 4,822,341; 5,041,098; and, 4,790,826. None of the
foregoing patents disclose a system having the features of this
invention. U.S. Pat. No. 4,447,237 describes improvements in a
valving slit which includes the provision of a flattened sleeve
within an elastomeric body presenting opposed interior surfaces
interengaged when the valving slit is in the closed condition and
spaced apart when the valving slit is in the open condition.
SUMMARY OF THE INVENTION
[0010] A hemodialysis and vascular access system comprises a PTFE
end which is sutured to an opening in an artery at one end and the
other end is placed into a vein using any technique which avoids
the need for an anastomosis between the silicone "venous" end of
the catheter and the vein wall. The system comprises any material,
synthetic or natural (i.e. vein) which can be sutured to the artery
(i.e. preferably PTFE) at one end while the other end is composed
of a material which is suitable for placement into a vein in such a
way that the openings in the "venous" end of the system are away
from the site where the graft enters the vein. The system may also
be constructed of multiple layers of materials i.e. PTFE on the
inside with silastic on the outside. The "Needle Receiving Site"
may also be covered with PTFE to encourage self sealing and tissue
in-growth.
[0011] A preferred embodiment comprises a combination of PTFE
conduit sewn to an artery on one end of the system with the other
end connected to a silastic-plastic catheter which can be
percutaneously inserted into a vein via an introducer. The venous
end may also be placed via open cut down. The seal around the
system where it enters the vein may be "self sealing" when placed
in percutaneous technique; it may be achieved with a purse string
when done by open technique "cut down"; or, it may be sewn to the
vein to create a seal with a "cuff" while the system continues
downstream within the venous system to return the arterial blood
away from the site of entry into the vein. The entire system can be
positioned subcutaneously at the completion of insertion. This
design is a significant improvement over existing methods because
it avoids the most frequent complication of current HD access
methods. By utilizing an indwelling venous end, one avoids creating
a sewn anastomosis on a vein which is prone to stenosis secondary
to neointimal hyperplasia. By having continuous flow through the
silastic end of the catheter, thrombosis of these catheters can be
avoided. Dialysis is made more efficient by decreasing
recirculation of blood which accompanies the use of side by side
dual lumen catheters inserted into a central vein. This invention
not only benefits the patient but it also speeds dialysis thus
saving time and money.
[0012] To summarize, the Squitieri Access System comprises a tube
composed of PTFE and a silastic catheter. This tube is used to
create an arteriovenous fistula. The PTFE end (arterial end) of the
tube is sewn to an artery while the silastic catheter end is placed
into the venous system by the Seldinger technique much like a
standard central line. The entire system is subcutaneous at the
completion of insertion. This system is a composite of the arterial
end of a "gortex graft" joined to the venous end of a "permacath".
This system enjoys strengths of each type of access and at the same
time avoids their weaknesses.
[0013] Accordingly, an object of this invention is to provide a new
and improved vascular access system.
[0014] Another object of this invention is to provide a new and
improved hemodialysis and vascular access system including an
easily replaceable needle receiving site which has superior
longevity and performance, is more easily implanted, more easily
replaced, and is "user friendly" i.e. easily and safely accessed by
a nurse or patient which is ideal for home hemodialysis.
[0015] A more specific object of this invention is to provide a new
and improved Squitieri hemodialysis and vascular access system
including a subcutaneous composite PTFE/Silastic arteriovenous
fistula.
[0016] A further object of this invention is to provide a new and
improved hemodialysis and vascular access system including a
fistula utilizing an indwelling silastic end which is inserted
percutaneously into the venous system and a PTFE arterial end which
is anastomosed to an artery and including a unique needle receiving
sites which are positioned anywhere between the ends and which have
superior longevity and performance.
[0017] A further object of this invention is to provide a system
constructed to preserve laminar flow within the system and at the
venous outflow end to reduce turbulence and shear force in the
vascular system to the degree possible.
[0018] A still further object of this invention is to provide a
system wherein the arterial end (PTFE) may also be placed by
percutaneous technique including one where blood entry holes are
distant from the site where blood enters the veins.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and other objects of this invention may be more
clearly seen when viewed in conjunction with the accompanying
drawings wherein:
[0020] FIG. 1 is a perspective view of the vascular access system
comprising the invention;
[0021] FIG. 2 is a cross-sectional view of the needle access site
taken along the line 2-2 of FIG. 1;
[0022] FIG. 3 is a cross-sectional view similar to FIG. 2 with a
needle inserted into the access site;
[0023] FIG. 4 is a cross-sectional view of the coupling between the
PTFE and the silicone venous end of the catheter;
[0024] FIG. 5 is a perspective view of an alternate embodiment of
the invention with one port having a tube sewn to a vein;
[0025] FIG. 6 is a perspective view of the embodiment in FIG. 5
with a silastic tube floated down a vein;
[0026] FIG. 7 illustrates a ringed tube sewn to an artery and
connected to a first access site which is joined to a second site
by silastic tubing and includes an outflow through silastic tubing
which is floated into the venous system;
[0027] FIG. 8 is similar to FIG. 7 but shows PTFE sewn to an artery
and silastic tubing floated into a different portion of the venous
system;
[0028] FIG. 9 depicts ringed PTFE tubing sewn to the subclavian
artery and a dual access site coupled to the venous system at its
other end;
[0029] FIG. 10 shows a multi-layered variation at the venous end of
the system;
[0030] FIG. 11 discloses a quick coupler design utilized in
conjunction with the system;
[0031] FIG. 12 is a unique port design utilized in conjunction with
the system;
[0032] FIG. 13 shows holes where ports can be fixed in place while
FIG. 13a and FIG. 13b show cross-sectional views which depict the
internal construction of the invention with FIG. 13b illustrating
multi-layered tubing; and,
[0033] FIG. 14 shows a variation of the system entry through vein
wall (i.e. not percutaneous or purse string) wherein a cuff, sewn
to vein as indwelling portion, is floated down stream.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] Referring to the drawings the Squitieri hemodialysis and
vascular system, as shown in FIG. 1, comprises a PTFE/Dacron (or
other synthetic or natural material) tube 10 of several centimeters
in length which is attached at one end by means of a coupling to a
needle access site or receiving site 20. Adjustable band 18
regulates the blood flow through the access site 20. The PTFE tube
10 is approximately 7 mm in diameter and transitions downward to an
open end portion 19 approximately 4 mm in diameter.
[0035] The access site 20 includes an in line aperture 16, see FIG.
2, having a silicone tube 41 connected thereto at one end leading
to a long flexible plastic/silastic/silicone tube 12 with
transverse holes 13 along its free end. The number of holes 13 may
vary within predetermined limits to achieve optimum results. The
end 36 may be beveled for ease of insertion. This tubular
arrangement functions as a subcutaneous connection between the
arterial and venous systems. It may also be modified to allow part
of the system to exit through the skin 14 (FIG. 3) to provide
access to the blood circulation without placing needles 15 (FIG. 3)
through the skin 14 into the fistula (usually at the PTFE end).
[0036] Along the length of the catheter specially constructed
needle access sites 20 (FIGS. 1, 7, 8, and 10) are located to
receive specially designed needles 15 into the system to gain
access to the blood stream which flows through aperture 16. This
method avoids perigraft bleeding which leads to thrombosis either
by compression of the graft by hematoma or by manual pressure
applied to the graft in an attempt to control the bleeding.
[0037] The needle access areas 20 which are designed to receive
needles 15 etc. to allow access to the system are in line conduits
with self-sealing material 25 which is here shown as a silicone
member 25 which can be located beneath the skin surface. The
silicone member 25 comprises an oval configuration exposed within
the frame 26 for ease of puncture. The system may be accessed
immediately after insertion without having to wait for the graft to
incorporate into the tissues as is the case with the current
methods of subcutaneous fistulas. These access areas 20 will
protect the graft since they are uniformly and easily utilized
requiring little training or experience. The "needle receiving"
sites 20 are designed in such a way to preserve laminar flow as far
as possible (i.e. not a reservoir arrangement). Needle receiver
sites 20 may be connected to a system via "quick couple" 45 for
easy exchangability, see FIG. 11.
[0038] FIGS. 2 and 3 disclose a needle access site 20 wherein a
silicone member 25 is mounted within a plastic or metal frame 26. A
protruding portion 27 of member 25 extends upwardly through the
aperture 31 while a flange portion 28 extends outwardly on both
sides of the portion 27 to be gripped by teeth 29 on the internal
surface of frame 26 and member 32. The frame 26 includes an in-line
aperture or passage 16 through the needle access site 20 for blood
flow. The blood flow is accessed by inserting needles 15 through
the silicone member 25 which is preferably oval in shape. The teeth
29 seal the arterial pressure. The passage 16 of the needle
receiving site 20 is tubular in shape.
[0039] The open end portion 19 of the PTFE tube 10 is sewn to an
opening in an artery 30, see FIGS. 5, 6, 7, 8 and 9, while the
flexible plastic tube 24 of the system having been inserted
percutaneously lies in the venous system in such a way that the
openings 13 in the silastic tube 12 are downstream from the site
where the flexible plastic tube 24 enters the vein 40 (see FIGS. 5
and 6). The venous end may be inserted via "cutdown". The purpose
of the system is to allow communication between an artery 30 and a
vein 40 in such a way that the system may be accessed by either
puncturing the PTFE segment or by entering the specialized "needle
receiving" site 20. This allows blood to flow from the system to a
hemodialysis (HD) machine (not shown) and then return into the
venous outflow portion at a more distal (venous end) location
allowing the blood to return from the HD machine (not shown) back
into the patient.
[0040] FIG. 4 discloses, as an alternative, a "glued" connection
between PTFE tubing 60 and silicone tubing 61 wherein the PTFE
tubing 60 is inserted into an enlarged portion of silicone tubing
61 wherein the longitudinally extending portion includes a raised
section 63 which locks a raised section 64 of PTFE tubing 61 within
the silicone tubing 61.
[0041] In this invention, the materials used may vary as specified
herein. The system may be constructed of one or more specific
materials. The arteries and veins used may also vary. Material may
also be covered with thrombus resistant coatings (heparin, etc.) or
biologic tissue. The system may in specific cases be "ringed" for
support.
[0042] The same concept of using an arterialized venous access
catheter may be applied to the use of long term indwelling
catheters used to give chemotherapy etc., making the current ports
obsolete as these new access systems will have a decreased
thrombosis rate and they will no longer need to be flushed as
continuous blood flow through the system makes thrombus formation
unlikely. This will definitely cut down on costs since it will
decrease nursing requirements in out patient settings, etc.
[0043] In alternate embodiments shown in FIGS. 5 and 6, the system
comprises an arterial reservoir structure or port 50 with needle
accessible top portions 51a and 51b, each of which a
preferably-constructed of silicone. The arterial reservoir
structure 50 is connected to an outlet tube 53 of PTFE
(gortex-ringed), which is sewn to an artery 30 at its other end.
The venous outlet tube portion 57 is constructed in a similar way
but it is either sewn to a vein 40 via gortex ringed portion 52 or
is placed percutaneously into the central circulation via an
indwelling venous (silicon) catheter 42 as shown in FIG. 6. There
is no continuous flow through this version of the system since the
ports are not connected. Flow is established when the system is
attached to an HD machine with a needle 15 in the arterial port 51a
to deliver blood to the HD machine and a second needle 15 is placed
in the venous port 51b to the vein 40 to deliver blood to the
patient. The ports 51a, 51b will remain flushed with heparin when
not in use to avoid clotting when accessed through the skin 14 with
needles 15. The ports 51a, 51b will also provide high flow access
to both the arterial and venous systems. FIG. 6 shows two separate
ports 51a and 51b with the outlet tube 53 sewn to an artery 30 and
the indwelling venous catheter 42 floated down a vein 40.
[0044] FIG. 7 illustrates, in an anatomical drawing, an outlet tube
53 of PTFE (ringed gortex) sewn to an artery 30 at 62 and coupled
at its other end 62a to the needle access site 20. The site 20, see
FIGS. 1-3, is joined by silastic tubing 68 to a second access site
20a which has an outlet silastic tube 65. The outlet tube 65
includes a plurality of perforations 66 at its outlet end which is
positioned in the venous system 67 through vein 40. Either site 20
or 20a can be used for needle access.
[0045] FIG. 8 depicts an embodiment similar to that of FIG. 7
except that the coupling between the artery 30 and the first needle
access site 20 is PTFE tube 69. The entry to the venous system 67
is via vein 40 which has silastic tubing 65 floated therein. A PTFE
tube portion 69a joins parts 20 and 20a.
[0046] FIG. 9 illustrates a dual needle access site 80 which is
coupled via outlet tube 53 of PTFE (gortex-ringed) to the
subclavian artery 30 and floated into the venous system 67 via
silastic tubing 65. The dual site 80 provides additional access
through 25a, 25b in approximately the same area with tubing (not
shown) extending through the dual site needle access site 80.
[0047] FIG. 10 depicts a variation of the invention at the venous
end wherein the outlet of the port 20 comprises PTFE tubing 91
located within a silastic catheter 92. This design is appropriate
if thrombosis is a problem in the outlet silastic portion of the
shunt.
[0048] FIG. 11 discloses a quick coupler 45 joining the PTFE outlet
tube 53 (gortex-ringed) to the port 46 in the needle access site
20. A plastic or metal member 47 includes a portion 48 which
engages the cylindrical PTFE tubing 10, an intermediate portion 49
extending perpendicularly outward and an end portion 43 tapered
outwardly at an angle and including an inward projection 44. The
projecting portion 44 of the member 47 engages a slot 54 in the
port 46 firmly fixing the cylindrical PTFE tubing 10 therebetween.
Portion 48 is made of flexible material to allow a gentle curve in
tubing as it exits/enters port.
[0049] FIG. 12 is an exploded view of a new port embodiment wherein
the port 71 comprises a frame 72 having an inlet coupling 73 and an
outlet coupling 74. The plastic or metal frame 72 includes a
recessed reservoir 76 and end walls 78a and 78b. An upper member 85
having a top or upper member 85a, a recess 83 and downwardly
projecting sides 87a and 87b fits within walls 77a and 77b. The
upper member 85 includes an oval silicone access site 90. The
member 45 rapidly couples the PTFE tubing 10 to site 71 with tubing
88 which fits over the inlet coupling 73 and the outlet coupling 74
with recessed portions 75a and 75b which engage tubing 88 (only one
of which is shown) and have couplers 45 (only one of which is
shown) which slide over the tubing 88 to engage the inlet and
outlet couplings 73 and 74.
[0050] A housing 86 includes a top portion 86a and a side portion
86b. The top portion 86a includes an aperture which surrounds and
provides a means for accessing the oval silicone access site 90.
This embodiment provides a quick assembly for a needle access site
71.
[0051] FIG. 13 shows a typical dual port system showing holes 55
where ports 20 can be fixed in place, while FIG. 13a and FIG. 13b
show cross-sectional views which depict the internal construction
of the invention with FIG. 13b illustrating multi-layered
tubing.
[0052] FIG. 14 discloses a cuff 56 which is made of PTFE and sewn
to a vein. No physiological/functional venues anastomosis is
created as blood is returned at the end of the system distant from
the cuff. The silastic end 12 may still be lined with PTFE.
[0053] The Squitieri Hemodialysis/Vascular Access System avoids
creation of a venous anastomosis, a revolutionary advancement, i.e.
there is no site for neointimal hyperplasia at a venous anastomosis
which accounts for the vast majority of PTFE arteriovenous graft
failures (60-80%). This is accomplished by returning the blood into
a larger vein via an indwelling venous catheter 42. The site of
blood return to the venous system is not fixed to the vein wall
where neointimal hyperplasia occurs with the standard PTFE bridge
graft. This feature represents a tremendous advantage over the
present grafts.
[0054] As a further advantage, the system is not stagnant and prone
to thrombosis, i.e. constant flow through the new system avoids the
problem of clotting inherent in indwelling dual lumen venous
catheters which remain stagnant when not in use. It also avoids
need to flush catheters with heplock thereby reducing nursing costs
to maintain the catheter.
[0055] The Squitieri system avoids externalization of components
which are prone to infection. Since dual lumen catheters exit the
skin 14, they frequently lead to sepsis requiring catheter removal
despite subcutaneous tunneling. This new access is entirely
subcutaneous.
[0056] Very importantly the system proposed herein, avoids problems
with the aspiration of blood from the venous system and
"positional" placement through continuous flow. A frequent problem
with dual lumen catheters is their inability to draw blood from the
venous system due to clot and fibrinous debris ball-valving at the
tip of a catheter. This new system receives blood directly from
arterial inflow which ensures high flow rates needed for shorter,
more efficient dialysis runs. It also avoids the frequent problem
of the catheter tip "sucking" on the vein wall inhibiting flow to
the dialysis machine and rendering the access ineffective.
[0057] The system avoids recirculation seen with dual lumen
catheters resulting in more efficient and more cost effective
dialysis.
[0058] The system avoids the need for temporary access with
incorporation of "Needle Access Sites" 20. A-V fistulas and gortex
grafts must "mature" for several weeks before use. This creates a
huge strain on the patient as well as the doctor to achieve
temporary access while waiting to use the permanent access.
Temporary access is very prone to infection, malfunction and vein
destruction. By placing sites 20 designed to receive needles 15
along the new access, the system may be used the day it is
inserted.
[0059] The system avoids PTFE needle site damage with the
incorporation of "Needle Access Sites" 20. Needle access directly
into PTFE is presently uncontrolled and user dependent. Often, PTFE
is lacerated by access needles. While this system may be accessed
via the PTFE segment, the needle receiving sites are the preferred
method. This leads to excessive bleeding which requires excessive
pressure to halt the bleeding causing thrombosis of the graft.
"Needle Access Sites" 20 on the Squitieri access system allow safe,
quick, and easy entry into the system and avoid the complications
inherent in placing needles directly into PTFE. It also avoids
perigraft bleeding which will compress and thrombose the graft. By
eliminating the long time needed to compress bleeding at the needle
site, the system shortens dialysis runs.
[0060] The Squitieri system permits an easier, faster insertion
technique. Only one anastomosis the arterial end and a percutaneous
placement of the venous end is required. A modification allows the
system to be sutured to the vein wall while the system tubing is
floated down stream from this site where the system enters the vein
40. This saves operating room time at thousands of dollars per
hour. The technique is easier with faster replacement. It avoids
difficult and time consuming revision of venous anastomosis
required to repair venous outflow occluded by neointimal
hyperplasia. If the system malfunctions, the silastic catheter end
65 slips out easily and the arterial end of the outlet tube 53 is
thrombectomized. New access sewn to the thrombectomized end of the
outlet tube 53 of PTFE at the arterial end and the silastic venous
end is replaced percutaneously via Seldinger technique or "open
technique".
[0061] The end result of the above advantages translates into
superior patency rates and a decreased complication rate with this
new system. Patients are spared the repeated painful
hospitalizations for failed access as well as the emotional trauma
associated with this difficult condition. The physicians are spared
the dilemma of how to best treat these patients. This system will
have a large impact on the current practice of vascular access in
areas such as hemodialysis; plasmapheresis; chemotherapy;
hyperalimentation; and chronic blood draws.
[0062] While the invention has been explained by a detailed
description of certain specific embodiments, it is understood that
various modifications and substitutions can be made in any of them
within the scope of the appended claims which are intended also to
include equivalents of such embodiments.
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