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.

Description

51 preferably constructed of silicone. The reservoir 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 52 is constructed in a similar way but it is either sewn to a vein 40 via gortex ringed portion 52 52a 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 one the tube 53 sewn to an artery 30 and the other tube 42 floated down a vein 40.

FIG. 7 illustrates in an anatomical drawing, a ringed gortex tubing 53 sewn to an artery 30 at 62 and coupled at its other end 63 to the needle access site 20. The site 20, see FIGS. 1-3, is joined by silastic tubing 64 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.

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. 69a depicts PTFE joining parts 20 and 20a.

FIG. 9 illustrates a dual needle access site 80 which is coupled via ringed PTFE 53 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 80.

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. The design is appropriate if thrombosis is a problem in the outlet silastic portion of the shunt.

FIG. 11 discloses a quick coupler 45 joining the PTFE tubing outlet tube 53 to the port 46 in the needle access site 20. A plastic or metal member 47 includes a portion 48 which engages the cylindrical 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 PTFE 10 therebetween. 45a Portion 48 is made of flexible material to allow a gentle curve in tubing as it exits/enters the port.

FIG. 12 is an exploded view of a new port embodiment wherein the port 71 comprises a frame 72 having an inlet 73 and an outlet 74. The plastic or metal frame 75 includes a recessed reservoir 76 and end walls 78a and 78b. An upper member 85 having a recess 86 and downwardly projecting sides 87a and 87b fits within walls 77a and 77b. 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 88a and 88b and have couplers 89a and 89b which slide over the tubing 88a, 88b to engage the couplings 73 and 74.

FIG. 13 shows a typical dual port system showing holes 55 where ports 20 can be fixed in place.

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.

The upper member 86 includes an oval silicone access site 90 with an outer housing 91 which includes an aperture 92 surrounds the silicone oval 90. This embodiment provides a quick assembly for a needle access site 71.

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.

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.

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.

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.

The system avoids recirculation seen with dual lumen catheters resulting in more efficient and more cost effective dialysis.

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.

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 elminating the long time needed to compress bleeding at the needle site, the system shortens dialysis runs.

The Squitieri system permits an easier, faster insertion technique. Only one anastomosis at 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 PTFE end 53 is thrombectomized. New access sewn to the thrombectomized PTFE at the arterial end and the silastic venous end is replaced percutaneously via Seldinger technique or “open technique”.

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.

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.

Claims

1. A Squitieri hemodialysis and vascular access system to shunt blood between a vein and an artery the system comprising:

(a) a first tube having a first end adapted to be connected to the artery and a second end;

(b) a second tube having a first end adapted to be connected to the vein and including a plurality of apertures extending therethrough and having a second end; and

(c) a needle access port having a frame including a conduit extending therethrough, said frame having an inlet connected to the second end of the first tube and an outlet connected to the second end of the second tube to provide a flow path for blood and a silicone member protruding from the frame to provide access for needles into the flow path, wherein the needle access port includes:

an outer frame member having an upper surface including an aperture extending therethrough and downwardly extending walls about its periphery having inlet and outlet apertures, wherein the upper surface includes a lower portion having a plurality of teeth;

a silicone member mounted within the frame having a surface engaged by the frame teeth and an upwardly protruding portion extending through the frame aperture; and

a second frame member having a transverse conduit extending between the inlet and outlet apertures, an upper surface having a plurality of teeth engaging the silicone member to effect a seal and wherein the second frame member is positioned within the walls of the first frame member.

2. The Squitieri hemodialysis and vascular access system of claim 1, wherein:

the first tube corresponds to PTFE tubing;

the second tube corresponds to silicone tubing; and

the protruding silicone member has an oval configuration.

3. The Squitieri hemodialysis and vascular access system of claim 1, wherein the first tube includes rings mounted thereabout to provide additional strength.

4. The Squitieri hemodialysis and vascular access system of claim 1 further comprising:

a second needle access port having an inlet and an outlet and silastic silicone tubing coupling the inlet of the second needle access port to the outlet of the other needle access port and wherein the outlet of the second access port is coupled to the second end of the second tube.

5. The Squitieri hemodialysis and vascular access system of claim 1 wherein:

the first tube is provided as PTFE tubing which is adapted for attachment to the artery at one end and coupled to the access port at the other end; and

the second tube is provided as silicone tubing which is coupled to the needle access port at one end and is capable of being floated within the vein at the other end.

6. The Squitieri hemodialysis and vascular access system of claim 1, wherein:

the first tube is inserted within an outer silicone tubing at the inlet to the needle access port.

7. The Squitieri hemodialysis and vascular access system of claim 1, further including:

an adjustable band mounted about the first tube at the inlet to the needle access port to regulate blood flow.

8. The Squitieri hemodialysis and vascular access system of claim 4, wherein:

a second needle access port is mounted to the needle access port, said ports having a single frame and a conduit extending longitudinally therethrough to the outlet tubing.

9. A Squitieri hemodialysis and vascular access system to shunt blood between a vein and an artery, the system including:

(a) a first tube having a first end adapted to be connected to the artery;

(b) a second tube having a first end adapted to be connected to the vein and including a plurality of apertures extending therethrough and having a second end;

(c) a needle access port having a frame including a conduit extending therethrough, said frame having an inlet connected to the second end of the first tube and an outlet connected to the second end of the second tube to provide a flow path for blood and a silicone member protruding from the frame to provide access for needles into the flow path; and

a quick coupler for joining the first tube to the needle access port comprising a port member projecting outwardly from the frame inlet and having a circumferential slot extending thereabout, a cooperating member having an outer portion extending concentrically with the first tube and a portion extending outwardly therefrom and an outwardly sloped portion extending over the projecting port member and having an inner circumferential projection which engages the circumferential slot, and wherein the first tube extends over the port member to be engaged by the projecting portion of the cooperating member within the slot and a removable coupling which snaps over the cooperating member forcing it into a sealed engagement with the port member.

10. A Squitieri hemodialysis and vascular access system to shunt blood between a vein and an artery, the system including:

(a) a first tube having a first end adapted to be connected to the artery;

(b) a second tube having a first end adapted to be connected to the vein and including a plurality of apertures extending therethrough and having a second end; and

(c) a needle access port having a frame including a conduit extending therethrough, said frame having an inlet connected to the second end of the first tube and an outlet connected to the second end of the second tube to provide a flow path for blood and a silicone member protruding from the frame to provide access for needles into the flow path, wherein the needle access port comprises:

a first member having a base, walls extending upwardly therefrom to form an enclosed area, and outwardly extending couplings on opposite walls thereof at the inlet and outlet of said port;

a second member having a top including an upper aperture, downwardly extending side walls engaging the walls of the first member and having a conduit extending from the inlet to the outlet and a silicone member projecting form the upper aperture to provide needle access; and

a tube mounted over each coupling and a coupler which fits over each tube to seal the tubes to the couplings.

11. The Squitieri hemodialysis and vascular access system of claim 1, wherein:

the second tube is capable of being floated within a vein at the one end and the plurality of apertures in the second tube are distant from the site where the second tube is inserted into the vein, said second tube not being fixed to the vein wall.

12. A hemodialysis and vascular access system comprising:

an arterialized indwelling venous catheter having a graft section provided from a material which is biocompatible with an artery, has a nonthrombogenic characteristic, which is adapted for long term attachment to an artery and which includes a region for repeated needle access and a catheter section, with a first end of said graft section adapted to be coupled to an artery and a portion of the catheter section adapted to be inserted within a vein at an insertion site, said catheter section portion 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 vein itself and wherein the at least one opening is distant from the insertion site such that blood flows from the artery through the catheter and is returned to the vein through the at least one opening while providing laminar blood flow between the artery and the vein.

13. The hemodialysis and vascular access system of claim 12, further comprising:

at least one needle having a first end coupled to a hemodialysis device and having a second end adapted for insertion directly into said graft section of the catheter to shunt the blood flow through the dialysis device.

14. The hemodialysis and vascular access system of claim 13 wherein said graft section 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.

15. The hemodialysis and vascular access system of claim 14 wherein said first and second tubes are adapted for percutaneously placement.

16. The hemodialysis and vascular access system of claim 14 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.

17. A hemodialysis and vascular access system, comprising:

an arterialized indwelling venous catheter having a graft section provided from a material which is biocompatible with an artery, has a nonthrombogenic characteristic, which is adapted for long term attachment to an artery and which includes a region of repeated needle access and a catheter section, with a first end of said first graft section adapted to be coupled to an artery and a portion of the catheter section adapted to be inserted within a vein at an insertion site, said catheter section portion having an outside diameter which is less than an inner diameter of the vein 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 vein itself and wherein the at least one opening is distant from the insertion site such that, in operation, blood flows from the artery through the catheter and is returned to the vein through the at least one opening while providing laminar blood flow between the artery and the vein 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.

18. The hemodialysis and vascular access system of claim 17 wherein the graft section 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.

19. The hemodialysis and vascular access system of claim 18 wherein said first and second tubes are adapted for percutaneous placement.

20. The hemodialysis and vascular access system of claim 18 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.

21. A hemodialysis and vascular access system as in claim 17, wherein the graft section comprises PTFE.

22. A hemodialysis and vascular access system as in claim 17, wherein the graft section comprises polyethylene terephthalate.

23. A hemodialysis and vascular access system as in claim 17, wherein the graft section has a diameter of approximately 7 mm.

24. A hemodialysis and vascular access system as in claim 17, wherein the first end of the graft section has a diameter of about 4 mm.

25. A hemodialysis and vascular access system as in claim 17, wherein the catheter section comprises silicone.

26. A hemodialysis and vascular access system as in claim 17, wherein a downstream end of the catheter section is provided with a bevel.

27. A hemodialysis and vascular access system as in claim 17, additionally comprising an access segment for receiving a needle to allow access to blood flowing through the catheter.

28. A hemodialysis and vascular access system as in claim 27, wherein the access segment comprises a self sealing material.

29. A hemodialysis and vascular access system as in claim 28, wherein the self sealing material comprises silicone.

30. A hemodialysis and vascular access system as in claim 28, wherein the access segment is removably connected to the access system.

31. A hemodialysis and vascular access system as in claim 27, further comprising a support structure in the access segment.

32. A hemodialysis and vascular access system as in claim 31, wherein the support structure comprises a frame.

33. A hemodialysis and vascular access system as in claim 31, wherein the support structure comprises ridges.

34. A hemodialysis and vascular access system as in claim 33, wherein the ridges comprise teeth.

35. A hemodialysis and vascular access system as in claim 17, wherein at least a portion of the indwelling venous catheter comprises multiple layers.

36. A hemodialysis and vascular access system as in claim 35, wherein the multiple layers comprise a first PTFE layer and a second silicone layer.

37. A hemodialysis and vascular access system as in claim 36, wherein the first PTFE layer is an inner PTFE layer and the second silicone layer is an outer silicone layer.

38. A hemodialysis and vascular access system as in claim 37, wherein the multiple layers further comprises a PTFE coating on the outer silicone layer.

39. A hemodialysis and vascular access system as in claim 17, wherein said graft section and said catheter section comprise a material selected from the group consisting of PTFE, silicone, or flexible plastic.

40. A hemodialysis and vascular access system as in claim 17, comprising first and second needle access sites.

41. A hemodialysis and vascular access system as in claim 17, wherein the catheter section comprises a long, flexible plastic tube.

42. A hemodialysis and vascular access system as in claim 17, wherein the region for repeated needle access comprises needle receiving sites(s) and comprises an internal chamber that is tubular in shape.

43. A hemodialysis and vascular access system as in claim 17, wherein the region for repeated needle access comprises a self-sealing material.

44. A hemodialysis and vascular access system as in claim 17, wherein the catheter section comprises a silicone section.

45. A hemodialysis and vascular access system as in claim 44, wherein the silicone section is lined with PTFE.

46. A hemodialysis and vascular access system as in claim 17, wherein the region of repeated needle access comprises multiple layers.

47. A hemodialysis and vascular access system as in claim 46, wherein the multiple layers comprise PTFE on the inside and silicone on the outside.

48. A hemodialysis and vascular access system as in claim 46, wherein the multiple layers comprise PTFE on the inside and silicone disposed outside of the PTFE.

49. A hemodialysis and vascular access system as in claim 17, wherein the material providing the graft section comprises a thrombus resistant coating.

50. A hemodialysis and vascular access system as in claim 49, wherein the thrombus resistant coating comprises heparin.

51. A hemodialysis and vascular access system as in claim 17, wherein a nonthrombenic characteristic is provided by continuous flow of blood through at least the graft section.