The goal of this Phase I STTR proposal is to demonstrate the feasibility of a novel prosthetic venous valve design concept. One of the ultimate goals in vascular surgery is to develop a successful prosthetic venous valve to replace defective valves in patients with chronic venous insufficiency (CVI). More than 8 million Americans suffer from the debilitating consequences of CVI. Many surgeons believe that replacing the incompetent valves in these patients will improve their conditions. However, transplanted valves derived from upper limbs or from animals have had limited success and prior versions of artificial vein valves have failed from thrombosis or intimal hyperplasia in the challenging hemodynamic environment of the venous circulation. Thus, rectifying the underlying etiology of the disease in these patients remains unresolved and these patients are relegated to traditional conservative, compression therapies. The novel venous valve design concept that BioMedical Reseach Associates proposes for evaluation could well serve as the platform upon which a successful prosthetic venous valve prototype can be designed. This design concept has been conceived based upon observations of venous valves from normal subjects and has worked successfully in crude flow loop to prevent regurgitation. In this Phase I proposal, feasibility of the design concept will be rigorously assessed by inserting preliminary valve protoypes in an in vitro flow loop designed to mimic human venous physiology and comparing performances of these prototypes under physiologic flow conditions to benchmarked data derived from normal human subjects. The deliverable from this research will be the conclusion whether the design concept is feasible or not compared to native vein valves and, if the concept is feasible, directions that the Phase II research should take for design improvements. If the ultimately developed prototype remains patent and competent over time in vivo, a prosthetic venous valve could be manufactured that would significantly benefit this challenging population of patients. [unreadable] [unreadable]