Improvement of fabrication process of vacuum formed valves for ventricular assist device

In order to provide an inexpensive ventricular assist device (VAD), we developed a 20mL-VAD which was followed by Prof. Kolff's design, but two problems were found; 1) Big amount of regurgitation through inlet bileaflet valve. 2) High resistance of outlet trileaflet valve. Following trials were carried out to settle them; 1) In the manufacturing process of the bileaflet valve, elastic material was used instead of hard plastic plate. Then, regurgitation could be reduced to 1/6. Moreover, total manufacturing process could be dramatically simplified. 2) In the manufacturing process of the trileaflet valve, leaflet thickness was well controlled around 0.2 mm with the aid of a special ring which was located around the valve mold. Then, lower resistance could be achieved by a thin (0.19mm) leaflet valve. Moreover, all valves could be passed the durability testing for 14 days. These data is helpful towards a pre-production stage of the VAD development.