CAVITATION THRESHOLD WITH RESPECT TO DP DT - EVALUATION IN 29 MM BILEAFLET, PYROLITIC CARBON HEART-VALVES/

A total of 15 bileaflet mechanical heart valves were studied in a puls e duplicator at the Helmholtz Institute (Aachen, Germany) under condit ions approximating first, a physiological pressure curve and subsequen tly, a sinusoidal pressure curve. In this study Edwards-Duromedics val ves of the modified specification were compared with the earlier versi on of the Edwards-Duromedics valve as well as with St. Jude Medical va lves. Each valve was tested at a series of nine (9) conditions. At eac h condition, without altering the valve installation or the systemic c onditions, each valve was filmed by two separate video systems: the He lmholtz Institute strobe light system and a high speed video recording system. All data, as recorded by each system, was then independently analyzed by both of the two contributing groups and subsequently compa red. In this manner, it was possible to objectively verify not only th e consistency of the data obtained, but to also determine the relative reliability of the methods for cavitation threshold detection.