Assessment of thermal dissipation effects in a ventricular assist device - biomed 2013

The heat generated during normal operation of an implantable Left Ventricular Assist Device (LVAD) can have a deleterious effect on the surrounding tissue as well as the blood flowing through the device. This effect is often overlooked and might also result in heart pump failure. Therefore, for a comprehensive design evaluation it is essential to accurately model the thermal dissipation in a LVAD system to ensure safety and device reliability. The LifeFlow artificial heart pump is a magnetically suspended axial flow LVAD in which the motor as well as the suspension system are the primary sources for heat generation. The objective of this study is to perform a thorough thermal analysis of the device using a combination of heat transfer equations, 3D-Finite Element analysis and 3D-CFD modeling. Particularly, the effects of heat generated on blood passing through the device due to the motor, magnetic suspension system and housing are studied. Conduction and convection effects due to the above contributors are analyzed. In addition, temperature distributions are estimated for different flow rates and pressure differentials. As a result of this study, it can be inferred if nominal operation of the LifeFlow LVAD would have any significant thermal effects on blood passing through the device. Results show that there is a 2.2°C temperature increase in the magnetic suspension system during nominal operation, while the blood temperature is increasing by 1.6°C. Assessment of thermal effects is crucial since high temperature exposure of blood could ultimately affect the patient whose systemic circulation is supported by the LVAD.