Effect of Internal Thrombus Formation on the Performance of the Pump of an LVAD

Donors’ unavailability has worsened the situation for end-stage heart failure patients. Therefore, left ventricular assist devices (LVAD) are becoming an increasingly important alternative for saving the lives of patients who are either unresponsive to medical therapy, are ineligible for heart transplantation, or are awaiting a donor. However, post-implant complications have been reported among which thrombosis is vital. This work aims to study the effects of internal thrombus formation on pump performance. For this, CFD simulations of a normal pump and the same pump with clots inside it have been carried out using ANSYS-CFX. Simulation outcomes are presented in the form of pressure head and wall shear stress variation for both, normal and thrombotic pumps. For a better comparison, absolute increase/decrease (in percent) in parameters’ values from normal to thrombotic pump have been calculated. Trends of study outcomes such as a decrease in pressure head generation can be used for the detection of thrombus inside the pump. This study can also be extended to other LVAD components including the inflow cannula, and the outflow graft for a failsafe operation of the system. Further, based on the present study a method of identification of internal thrombosis in the pump has been proposed.