Design, analysis and validation axial ventricular assist device

Abstract

Ventricular assist devices (VADs) have played a major role in alleviating end-stage cardiovascular diseases as a bridge to transplantation and more recently as a long-term solution. The axial flow blood pump has become the focal point in the research for mechanical circulatory devices owing to its compact size, low thrombosis, and low hemolysis. This project involves the development of an axial flow Left Ventricle Assist Device (LVAD). LVAD is a mechanical pump that is implanted inside the human body to help a weakened heart. The LVAD flow conditions depend on the interaction between the pump and the native heart. An axial flow LVAD is chosen as it operates efficiently at high rotational speeds and is of great clinical benefit to patients with pulmonary hypertension. Reduction of hemolysis is one of the main criteria for the design of an LVAD. Hemolysis is the bursting (lysis) of red platelets and the arrival of their substance into encompassing liquid (for example blood plasma). The shear stress generated in the pump is one of the main reasons for causing hemolysis. Other reasons include blood stagnation in a flow field, exposure time, surface roughness, blade and casing geometry, and other many operating conditions. In our project, we modeled one implantable axial pump in SolidWorks and it was then analyzed using ANSYS CFX and the shear stress field is obtained from solving transport equations for velocity components. Using the obtained shear stress value, the hemolysis rate was calculated. The results obtained were verified by comparing with the results obtained from a similar work done in a published journal article.