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

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 ti...

AI Technical Summary

Benefits of technology

[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.

[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.

[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.

Problems solved by technology

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.

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.

These catheters are prone to kinking, clotting, infection, and poor flow rates.

The ports are prone to clotting and must be continually flushed since they are a stagnant system.

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.

Images