Design and optimization of antithrombogenic surface textures on bileaflet mechanical heart valves

BACKGROUND: High shear rate and non-physiological turbulent flow caused by bileaflet mechanical heart valves (BMHVs) lead to platelet activation and adhesion, which can cause rapid thrombus growth and severe consequences. METHODS: This study employed computational modeling to analyze the effect of surface texture on flow field around the BMHVs. The textures' positional, geometric, and dimensional parameters were optimized based on flow field analysis. The textured BMHVs were then implanted in sheep for 6 months, with pyrolytic carbon BMHVs serving as the control group. RESULTS: The textured BMHVs significantly reduced high-velocity, low-velocity, high turbulent shear stress, and high shear rate regions in the flow field. Post-implantation, the experimental groups with textured BMHVs exhibited lower levels of platelet activation and neither the intrinsic nor extrinsic coagulation cascade reactions were activated in the sheep. Detailed observations revealed an absence of erythrocyte or platelet adhesion within the grooved texture regions, with minimal adhesion at the peripheral edges of the textured areas. CONCLUSION: The optimized surface textures on BMHVs effectively reduce adverse flow conditions and platelet activation, potentially decreasing the need for anticoagulant therapy and minimizing the associated bleeding risks. These findings are crucial for enhancing the long-term safety and efficacy of BMHV implantation.