Design and development of a pulsatile axial flow blood pump as a left ventricular assist device

Abstract

Each year all over the world, Millions of patients from infants to adults are diagnosed with heart failure. A limited number of donor hearts available for these patients results in a tremendous demand of mechanical circulatory support (MCS) system, either in the form of total artificial heart (TAH) or a ventricular assist device (VAD). Physiologically MCS are expected to provide heart; a time to rest and potential recovery by unloading the ventricle, while maintaining the adequate peripheral as well as coronary circulation. Existing ventricular assist devices (VAD) have employed either displacement type pulsatile flow pumping systems or continuous flow type centrifugal/rotodynamic pumps systems. Displacement type devices produce a pulsatile outflow, which has significant benefits on vital organ function and end organ recovery. Continuous flow devices are small and can be placed within body using minimal invasive procedures, in addition they reduces infection as well as mechanical failure related complications. Despite availability of success stories for both types of pumping systems, the selection of the either of them is an ongoing debate. This thesis aims to merge the advantages of displacement pumps (pulsatile flow) and axial-flow pumps (continuous flow) into a novel left vertical assist device (LVAD), by designing a novel minimal invasive, miniature axial-flow pump producing pulsating outflow for the patients having early heart failure and myocardial infarction as a Bridge-To-Recovery (BTR) or Bridge-To-Decision (BTD) device. The design of VAD, the experimental setup and dedicated control system were developed for the in vitro evaluation of pulsatile flow. Computational fluid dynamics (CFD) had been employed for the detail investigation of pulsatile flow. In addition, CFD was also applied to optimize the pulse generation for low haemolysis levels. Outcome of the study produces comprehensive understanding for the generation of pulsatile flow using an axial flow pump. Further, it provides the means of generating a controlled pulse that can regulate flow rate for varying heart rate within low haemolysis levels.