Effect of blade curvature on the hemolytic and hydraulic characteristics of a centrifugal blood pump

Abstract

Aims: Impeller design has a significant impact on the overall performance of a blood pump. In this study, the effect of the blade curvature was investigated by performing in silico and in vitro studies on a recently developed centrifugal blood pump. Methods: A computational fluid dynamics study was performed for the flow rates of 3-5 L/min at 2000 r/min. The computational fluid dynamics model was also applied on the US Food and Drug Administration (FDA) benchmark blood pump to validate our computational method. The relative hemolysis index was calculated with the Eulerian hemolysis estimation method for five impellers with the wrap angles ranging from 0 degrees to 240 degrees. Hydraulic experiments were conducted for the validation of computational fluid dynamics results. In addition, the curved-blade impeller (120 degrees) and the straight-blade impeller (0 degrees) were evaluated with in vitro hemolysis tests using human blood. Results: The wrap angle of 120 degrees provided the best hydraulic and hemolytic performance. Pump achieved the physiologic operating pressures and flows with 85-115 mmHg at 2.5-5.9 L/min. Compared to the straight-blade impeller, the 120 degrees model reduces the relative hemolysis index and the plasma-free hemoglobin near 72.8% and 56.7%, respectively. Comparison of in silico and in vitro results indicated the similar trend to the blade curvature. Conclusion: Introducing a blade curvature enhanced the hydrodynamic and hemolytic performance compared to the straight-blade configuration for the investigated centrifugal blood pump. The findings of this study provide new insights into centrifugal blood pump design by examining the influence of the blade curvature.