Design, optimization, and mechanism study of antithrombotic microstructure surfaces on mechanical heart valves inspired by shark-skin riblet

Background: Bileaflet Mechanical Heart Valves (BMHVs) are prone to thromboembolic complications.The shark-skin riblet surfaces can reduce drag, so maybe it can solve this thrombosis problem.Objective: Add riblet surfaces on BMHVs and see whether it can reduce shear stress of the blood.If shear stress is reduced, then this riblet surfaces can decrease the risk of thrombosis.Methods: The study first verified through Particle Image Velocimetry (PIV) experiments that adding micro-riblets to the leaflet surface significantly reduces flow obstruction.Subsequently, this study used Computational Fluid Dynamics (CFD) to further analyze the mechanism of the riblets' effect on the shear stress field and optimized the riblet geometric parameters.Results: The PIV results showed a significant increase in blood flow rate on the side with riblets, confirming that riblets effectively reduce flow obstruction under heart valve conditions.The CFD simulation shows the shear stress of blood is lower when 28-degree, 0.5-mm deep riblet are added to BMHVs, and this is probably the optimum configuration.