Mechanical Heart Valves with Reduced Thromboembolic Risk

Our objective is to develop of a mechanical prosthetic heart valve with reduced thromboembolicrisk compared to valves currently available. Mechanical valves now are employed only with warfarinanticoagulation, a significant contributor to the morbidity and mortality associated with their use. Theapproach to be investigated is to eliminate the discontinuity between the smooth surface of the valvering and the textured surface of the suture cuff used for surgical fixation. This is to be accomplishedby employing an integrally textured metal surface on the valve ring. The new valve is a tilting diskdesign using a pyrolytic carbon-coated occluder. The valve will be studied in vitro in a pulse duplicatorto characterize its forward flow pressure gradient, effective open area, and overall efficiency. Flowvisualization will be used to adjust the valve geometry to eliminate regions of stasis or flow separation.Wear of the textured metal surface will be examined by constructing an accelerated cyclic test fixturewhich will enable prototype valves to be tested for mechanical wear for the equivalent of two years ofreal time operation. Finally, a series of valves are to be implanted in adult sheep to study the in vivoperformance and safety of the prosthesis. If successful, the textured surface valve has the potential toreduce or eliminate the requirement for warfarin use, while providing a prosthesis with greatermechanical endurance than bioprosthetic tissue valves, the most commonly used alternative to themechanical valves currently available.