Investigation of a Ventricular Assist Device for Serial Production

Abstract

We have been investigating a pulsatile, pneumatic ventricular assist device (VAD) for extracorporeal assistance of the left and right heart. We believe that this VAD will be competitive in terms of cost, and better in performance when compared to existing cardiac assist devices, including centrifugal and intra-aortic balloon pumps. To make the VAD as cost-effective as possible, several aspects of its construction and design were investigated. The VADs were vacuum-formed in 20-ml and 40-ml sizes, both in Pellethane (Dow Chemical Japan, Tokyo, Japan) and an inexpensive food-grade polyurethane. Individual parts of the VADs were assembled using high-frequency welding and special glueing techniques. To reduce thrombus formation, the 20-ml VAD employed a novel active diaphragm-housing (D-H) junction, with immobilized-heparin blood contacting surfaces. The VADs have been tested both in vitro and in vivo in chronic animal experiments, the longest survival being with a sheep with a 20-ml VAD that operated thrombus-free for a period of 3 months. The 40-ml VAD, which yields 61/min in vitro, is currently under development. Using the vacuum-forming process, we were able to fabricate VADs to a reproducible quality and performance.