Improving the hemocompatibility of centrifugal mechanical circulatory support devices at low flow rates

BACKGROUND: An innovative solution has been recently proposed for the treatment of heart failure with preserved ejection fraction (HFpEF), using a centrifugal mechanical circulatory support (MCS) device. We sought firstly to assess the hemocompatibility of the proposed device. HFpEF treatment requires the blood pump to operate at low blood flow rate (0.05-0.5 L/min). Given high blood trauma expected in these conditions, we sought secondly to investigate design improvements in order to reduce this risk. METHOD: Computational fluid dynamics was used to analyze the blood fluid filled within the centrifugal pump and to estimate the blood trauma due to its operation. This assessment is based on the computation of integrated quantities such as the hemolysis index and the turbulent dissipation energy. RESULTS: The hemolysis index associated with the present device is comparable to the figures from HVAD. With the proposed pump, for instance, an index of 0.0036 is obtained at 1 L/min and 3000 rpm. Using thinner blades for the impeller allows a 12% reduction of the hemolysis index in average, while reducing its diameter leads to an index 2.8 folds lower at 0.5 L/min. CONCLUSION: The present investigation shows the promising hemocompatibility of our centrifugal pump. Concerns about very high hemolysis generated at low flow rates could be overcome by reducing the impeller diameter. Experimental validations are planned to support our findings.