In vitro investigation on opening angle and hydrodynamic performance of four bileaflet valves in mitral position

Four different designs of 25 mm bileaflet valves were tested in the mitral position using our originally developed in vitro test apparatus. By the aid of a high-speed video camera, it was observed that the SJM HP valve opened fully and the CM nearly opened fully (76°±2°). Max opening angle of the ATS and the On-X was 72°±3° and 81°±2° respectively whereas their opening angle was designed as 85° and 90°, respectively. Pressure gradients of the CM and the ATS were consistently higher than those of the On-X and the SJM HP. Closing volume for all the valves was within the acceptable range (<8%)