Significance: End Stage Renal Disease (ESRD) affects a rapidly growing population likely to exceed 1 million patients in the US by 2020. The standard treatment of 3 times per week hemodialysis (HD) has high complication rates and infection risks, results in undertreated patients, and is unsustainably costly to the health care system. Conventional vascular access site formation and maintenance issues result in more than 25% of HD patients using central venous catheters (CVCs), often for long periods and with even higher infection risks. Less expensive and more patient-friendly alternatives of home peritoneal dialysis (PD) and home hemodialysis (HHD) have not seen wide adoption, in part due to exit site infection risk (in the case of PD) and the need for repeated difficult needle sticks a home (in the case of HHD). The overall goal of this Phase II SBIR proposal is a solution for the critical unmet need of much-improved infection resistance for all types of needle-free dialysis access, including CVCs, PD catheters, and next-generation percutaneously placed ports for HD access. Innovation: We are developing a porous cuff that forms a tightly integrated seal between the cut edge of the skin and the surface of an implanted percutaneous device. Healionics'STARcuffTM has precisely engineered pore geometry (~35?m pores interconnected by ~15?m pore throats) that allows macrophage and dermal cell entry into every pore. This optimized structure promotes vascularized dermal integration and stable epidermal incorporation without migration, excessive fibrosis, or sinus tract formation. Other porous cuffs with larger (50-500?m) openings achieve mechanical retention by inducing fibrotic ingrowth, but are prone to cuff migration and biofilm formation. Smaller-pored cuffs with pore sizes less than 10?m are even more infection prone, providing shelter for infiltrated bacteria by restricting access for macrophages and other host defense cells. A STARcuff biointerface resists bacterial biofilm formation and recruits a stable, quiescent concentration of host macrophages into the biomaterial, restoring the natural skin barrier and enabling the body's natural defense mechanisms for fighting bacterial infection. Approach: We have successfully accomplished Phase I goals to 1) establish a porcine percutaneous implant bacterial challenge model, 2) establish a non-invasive technique (infrared thermography) for monitoring exit site infection and 3) demonstrate effectiveness of STARcuff in controlling and reducing this infection. These successful Phase I results position us to move STARcuff technology toward commercial realization on high medical impact percutaneous dialysis devices. Phase II specific aims are to 1) demonstrate improved long-term (9-month) infection resistance, 2) assess the robustness of the skin seal, and 3) extend studies to full CVC devices implanted into a blood vessel. Project success will result in major positive economic impact and Quality of Life benefit for all dialysis patients by reducing acute infection costs, increasing home dialysis use, and creating a healthier patient population. A major catheter company has already expressed commercial interest in the technology and is providing in kind support for the project.
End Stage Renal Disease (ESRD) affects a rapidly growing population, likely exceeding 1 million patients in the US by 2020. Patient quality of life and economic issues are major challenges to the present dialysis treatment center system established in the 1970's. All present methods require penetration of the natural skin barrier to bacteria. Medical treatment of resultant infections has become more costly than the dialysis itself and is a special problem with the catheters often used as a backup to needles for vascular access. Similarly, acceptance of less costly and more patient controlled alternatives such as home hemodialysis could be greatly improved by a needle free vascular access means, but implanted devices for this have suffered from infection problems at the skin interface. We are developing a biomaterial sleeve exhibiting very strong tissue integration and infection resistance at the skin exit sites of access devices. Project success will lead to significant improvements in dialysis effectiveness and efficiency.
