P40: Minimal hemolysis and platelet activation with VentriFlo True Pulse Pump, a novel pulsatile extracorporeal blood pump

Abstract

Objective: Early pre-clinical work with a novel pulsatile extracorporeal blood pump, VentriFlo True Pulse Pump, have demonstrated delivery of the normal, or heart-like, pulsatile flow. Subsequent design modifications have been implemented to enhance the quality of pulse applications across varying stroke volumes and circuit dynamics. The aim of this study was to support the device development with advanced in silico simulation. Methods: Steady state and transient computational fluid dynamic (CFD) models were generated using ANYSYS 17.2 software (ANSYS Inc., Canonsburg, PA) including SpaceClaim, ANSYS meshing, CFX, and CFD-Post tools. The flow velocity and wall shear stress during two different pump cycles (faster and slower) were evaluated to assess the hemolysis and platelet activation in accordance with Hellums’ criteria. The pump cycles were determined with typical VentriFlo pump filling and pumping times (faster: 0.35 sec each, slower 0.63 sec each). Results: The faster cycle exhibited a peak shear stress of 180 Pa and an exposure time of 0.075 sec, while the slower cycle demonstrated a peak shear stress of 110 Pa and an exposure time of 0.05 sec (Figure 1). Both values were below the Hellums’ threshold criteria for hemolysis and platelet activation. Conclusion: The refined VentriFlo pump demonstrated low hemolysis generation and platelet activation in the CFD model. Additional research efforts are ongoing.Figure 1. The wall shear stress and exposure time for two pump cycles, compared with Hellums’ thresholds.