Prosthesis-induced hemolysis: mechanisms and quantification of shear stress.

Over the past four decades, nearly three million prosthetic heart valves have been implanted worldwide. Despite improvements in valve designs and clinical management, the ideal mechanical heart valve has yet to be realized; hemolytic and thromboembolic complications remain the major obstacles. Towards this goal, a number of clinical and basic engineering studies have improved our understanding of how red blood cells can be damaged by the turbulent flow fields associated with current prosthetic mechanical heart valve designs. However, continued advances in understanding the hemolytic complications associated with different valve designs, and progress in making improvements to existing designs, will depend on the development of more sophisticated in vitro quantitative engineering techniques such as those described in this paper.