Abstract
In order to estimate the effect of the valve orientation angle on mechanical heart valve (MHV) cavitation in a pneumatic pulsatile ventricular assist device (PVAD), the valve was rotated from 0 to 90 degrees on an inclined horizontal plane. Tests were conducted under physiological pressures with heart rates of 80 bpm and a systolic ratio of 43%. A 23-mm Sorin Bicarbon bileaflet valve was installed in the inlet position of the pneumatic VAD, and the valve-closing velocity was measured with a closed circuit digital (CCD) laser displacement sensor. Images of MHV cavitation were recorded using a high-speed video camera, and cavitation bubbles were found to be concentrated along the leaflet tip. Cavitation bubbles were caused by the first valve closure, valve rebound and the second valve closure. The contact delay time for valve orientation angles of 0 and 30 degrees was longer than that for angles of 45, 60 and 90 degrees. The observation time of the cavitation bubbles caused by the first valve closure at 45, 60 and 90 degrees was longer than that of the bubbles caused by the valve rebound. The total observation time of cavitation bubbles for the left side leaflet was greater than that of bubbles for the right side leaflet.
