The Effect of Valve Type and Drive Line dP/dt on Hemolysis in the Pneumatic Ventricular Assist Device

Abstract: The objective of this experiment was to investigate the relationship between blood damage and drive line dP/dt and valve type in the pneumatic ventricular assist device. Two mock circulatory loops were assembled using 70–ml Penn State pneumatic ventricular assist devices, one fitted with convexoconcave (CC) valves and one fitted with monostrut (MS) valves. Use of a compliance chamber established three ranges of drive line dP/dt values. Using bovine blood and the methods of generalized estimating equations, it was found that drive line dP/dt was significantly associated with the index of hemolysis (p = 0.00): the lower drive line dP/dt values yielded lower indices of hemolysis. In addition, this association differed between MS and CC valves (p = 0.01); the MS valves consistently yielded a higher index of hemolysis than the CC valves across all drive line dP/dt ranges. However, the relative hemolytic potential of each valve type became much closer at low drive line dP/dt values (2,000–3,000 mm Hg).