Abstract
In this study, an ultracompact, lightweight, completely implantable pulsatile ventricular assist device (VAD) intended for 50-60kg-size patients was developed. The overall volume and weight of this VAD are 285ml and 380g, respectively. The in vitro tests were carried out to assess the device's capabilities. The mean pump output of 4-5l/min could be obtained with the pump rate of 80-100 BPM against the mean afterload of 100mmHg. The tri-leaflet valves made of polyurethane were used for inflow and outflow valves of VAD after comparing three types of artificial valve. Currently we have completed improvement on the device, and the development of a completely implantable VAD system including a transcutaneous energy transmission system (TETS), internal battery system, and a compliance chamber have been advancing. In an experimental using Ni-MH battery, increasing the number of batteries was found to extend the drive time of VAD but the efficiency decrease due to the increase in the input power. In addition regulating the input voltage of batteries to the 15-16V optimum drive voltage of VAD could drive VAD with high efficiency of 23-24% for 2.5h.
