AN INITIAL INVESTIGATION INTO THE WEAR AND DAMAGE WITHIN THE PIVOTS OF 3 TYPES OF BILEAFLET MECHANICAL HEART-VALVES

Two 29 mm St. Jude Medical valves, two 29 mm CarboMedics valves and tw o 29 mm Sorin Bicarbon valves were tested in a real time fatigue test rig. The test rig was run at 72 beats/min with a stroke volume of 70 m i for approximately one million cycles. Optical microscopy was used to investigate the valve surfaces. Possible deterioration of the surface finish was observed on the stops of the hinge recesses in the St. Jud e Medical and CarboMedics valves. In the Sorin valves areas of the pyr olytic carbon coating was worn away adjacent to and on the valve stops .