Estimation of mechanical heart valve cavitation in an electro-hydraulic total artificial heart.

The purpose of this study was to establish a method for estimating mechanical in vitro heart valve cavitation in an electro-hydraulic total artificial heart (EHTAH). The variations in the left driving pressure (LDP) slope of the EHTAH were used as an index of the cavitation intensity. The LDP slope was controlled by changing the stroke volume of the EHTAH. The stroke volume was changed from full-filling and full-eject to partial-filling and partial-eject conditions. A 25-mm Medtronic Hall valve was installed in the mitral position of the EHTAH. Cavitation bubbles were concentrated on the valve stop; the major cause of these cavitation bubbles was determined to be squeeze flow. The valve-closing velocity was found to be proportional to increases in the LDP slope and the stroke volume of the left blood pump. The cavitation intensity and the cavitation event rate increased with increases in the stroke volume of the EHTAH. A consistent correlation was observed between the valve-closing velocity and the cavitation intensity. The LDP slope of the EHTAH may play an important role in estimating the mechanical heart valve cavitation intensity.