ESTIMATION OF THE ABRASIVE WEAR COEFFICIENT IN LILLEHEI-KASTER CARDIAC-VALVE PROSTHESES

An approximate hemodynamic theory, which predicts the opening dynamics of the Lillehei-Kaster heart valve, is used in conjunction with an abrasive wear model to predict the wear process on the shields. The hemodynamic theory predicts markedly different opening dynamics between the mitral and aortic positions and is shown to give excellent correlation with the experimental results of other investigations. The abrasive wear model is shown to give excellent correlation with the experiments of others when the abrasive wear coefficient is taken as k equals 6. 4 multiplied by 10** minus **6. The theoretical results of this effort and the experimental data from clinical explants of other investigators is used to predict that occluder dislodgement is unlikely in less than 90 yr for either the mitral or aortic positions (for a mean cardiac output of 3. 8 l. min** minus **1 and a mean heart rate of 70 beats min** minus **1.