Effect of shear stress on platelet aggregation of low-flow centrifugal pump in vitro

Platelet aggregation and platelet adhesion in hemofilters or in oxygenators is a serious problem in blood purification or oxygenation system when using centrifugal pumps. In this study, in vitro evaluation of platelet aggregation and platelet adhesion was performed using two low-flow blood pumps with different impeller inlet shapes, corresponding to high shear stress and low shear stress. As a result, the pump predicted high-shear stress tends to have higher blood platelet aggregation than the pump predicted low-shear stress. The platelet activation in whole blood of the circuit is promoted within 20 minutes from the start of pump driving in both pumps. The platelet adhesion correlates with flow rate changes and is influenced by not only platelet aggregation ability but also the flow rate in the circuit by repeating adhesion and separation. It was found that measurement of the platelet aggregation ability of whole blood can provide a suitable measure to prevent platelet aggregation and platelet adhesion due to the shear stress by a blood pump.