ABSTRACT
Pre-clinical and clinical testing of artificial heart-valves has not been standardized. Therefore different centers have been using individual procedures. As a consequence, the results from different laboratories on different valves can be compared only after certain assumptions. In order to compare different valves under identical conditions, a pulse duplicator was developed and the Björk-Shiley and St. Jude Medical valves were studied in the aortic position under pulsatile flow, at stroke volumes ranging from 40 to 90 ml and frequencies from 40 to 130 cpm. Linear relationships were observed between the gradients as measured across the artificial valves and both, stroke volume and frequency. Loss of pressure divided by stroke volume, expressed as a function of frequency, was found to be a simple parameter to describe the fluid mechanical properties of an artificial valve under pulsatile flow and to compare different types of devices. The comparison of BS ABP and SJM aortic prostheses of equal diameter revealed the fluid mechanical properties of the SJM valve to be superior to those of the BS prosthesis under identical testing conditions.