Geometric Enhancements of an Arteriovenous Graft

End Stage Renal Disease (ESRD) is the degeneration of kidney function to remove uremic toxins from the blood. Currently there are over 484,000 sufferers of ESRD in the United States, with this figure predicted to rise to over 800,000 by 2020 [1]. The total cost of care for patients with ESRD was estimated to exceed 1 billion dollars in the United States [2]. A kidney transplant is the ideal solution for ESRD patients; however with the increasing number of ESRD patients the odds of receiving a donor kidney are poor. The alternative is hemodialysis. This process is involves the extraction of blood from the patient to an extracorporal machine. Blood is pumped at a rate of 350 mL/min to ensure effective dialysis. The blood is then returned to the body cleaned. The gold standard for hemodialysis access is the native arteriovenous fistula [3] with the most common type being the Brescia-Cimino fistula at the wrist [4]. In some subgroups the fistula performs poorly. In diabetics and the elderly, specifically over 70s [2] or can’t be constructed because of unsuitable blood vessels [5]. In this case an alternative is the synthetic AV graft. Made of polytetrafluoroethelyne, it has lower patency rates against the fistula [6] [7] mediated by the susceptibility to thrombosis induced by stenosis development and infection [7].The majority of stenosis development is within the venous anastomosis (kanterman1995). The formation of intimal hyperplasia (IH) leading to stenosis formation is caused by smooth cell proliferation and migration as a result of endothelial cells reacting to shear stress receptors. The development of IH has been linked to local hemodynamics and turbulence in the flow, which in turn are heavily influenced by the geometry of the graft.