Shear Stress Induced Thrombogenicity of a Trileaflet Mechanical Heart Valve

Abstract

Trileaflet mechanical valves are a popular topic in industry R&D due to their potential improvements to hemodynamic performance relative to industry-standard bileaflet mechanical valves and their mechanical durability relative to tissue valves. Novostia is currently attempting to bring their Lapeyre-Triflo trileaflet valve through FDA approvals, demonstrating a clear need and viability for the design concept. While some analysis of this new design has been done, there is a lack of research into the effect of the new leaflet geometry on peak shear stresses in the flow, which impact the thrombogenicity of the valve. Thrombosis is one of the leading causes of complications associated with mechanical heart valves on the market today. While many different factors contribute to the thrombogenicity of a heart valve, high shear stresses in the flow are classically considered to be a significant contributing factor due to the platelet damage that occurs in high shear stress regions. Specifically, our team examined whether shear stresses and resultant platelet damage are increased relative to classic bileaflet valve designs when the valve is in the open position at peak systole. The triangular leaflet geometry contains a sharp trailing edge, which could increase the shear stresses, and the design also introduces an additional region of flow (four flow regions rather than three), which brings potential for further impacts to shear stress downstream of the leaflets.