The objective of this Phase I SBIR proposal is to evaluate a novel vascular graft design for use as the arteriovenous (AV) graft component of a new needle-free access port. Significance: Hemodialysis patients require painful punctures with large needles for vascular access on a near-daily basis. This worsens quality of life, and the repeated tissue trauma makes maintenance of a reliable long-term access difficult. AV grafts (the safest option for the 40% of patients unable to sustain an autogenous fistula) are prone to thrombosis at the venous anastomosis and other needle-trauma-related complications such as infection and hematoma. A device that could circumvent the issues associated with needlesticks and provide patient- friendly long-term vascular access with low complication rate would have major impact. Innovation: STARport is a new percutaneous hemodialysis port under development that provides blunt cannula access to the inside of an AV graft. It uses Healionics'proprietary STAR(R) biomaterial at the tissue interface to overcome the exit site infection issue that stymied earlier attempts to commercialize similar port devices. STAR's sphere-templated structure has precisely-dimensioned microporosity optimized to promote capillary ingrowth, minimize fibrotic encapsulation, and facilitate the body's natural defenses against biofilm. A successful STARport must also overcome the anastomotic thrombosis issue, made especially challenging because the tissue-anchored port transmits hyperplasia-inducing stresses to the venous anastomosis. We propose to test "STARgraft" (a vascular graft made from STAR biomaterial) as the AV component for STARport. STAR's optimized pore structure, which takes advantage of a narrow pore size "sweet spot" where pore openings are the minimum size permitting vascular ingrowth, is ideally suited for promoting a thromboresistant bloodflow surface. Its exceptional biocompatibility should also create a smoother transition at the graft- vein anastomosis than existing graft materials, potentially reducing neointimal hyperplasia. STARgraft also features the STAR biointerface on the exterior of the graft to resist infection. Approach: The Phase I target milestones - to be achieved in a sheep model - are: 1) histological evidence that STARgraft (with midgraft connection to STARport) reduces neointimal hyperplasia compared to control ePTFE grafts, and 2) demonstration that STARgraft extends the functional patency of the device. A Phase II would address detailed device testing and preclinical demonstration of device longevity and function for dialysis as prerequisites for a clinical Early Feasibility Study.
End Stage Renal Disease (ESRD) affects a rapidly growing population, with more than 400,000 patients in the US presently undergoing hemodialysis treatment. Established methods require repeated penetration of the skin and blood vessels with needles for connection to external dialysis equipment. A needle free vascular access means would provide a much more patient friendly approach, but prior implanted devices for this have suffered from infection problems and from blockages of the connected vascular grafts. We are developing a biomaterial graft construction exhibiting both infection resistance and improved blood flow properties for use with an improved needle free access device. Project success will lead to significant improvements in dialysis effectiveness and efficiency.