In vitro hydrodynamic performance of various cardiac prosthetic valves tested in a modified nonpulsatile flow system

Hydrodynamic studies were performed in a modified nonpulsatile flow system to compare the efficiency of various prosthetic cardiac valves in vitro. Apart from direct flow/pressure relations across the valves the effective orifice area available for forward flow was determined by derivations of the Bernoulli hydrodynamic equation. By defining the relationship between calculated effective orifice area and known orifice area of the valves a more precise appraisal of the hydrodynamic characteristics of the various valve designs was possible.