TEST PROCEDURE FOR ARTIFICIAL MITRAL-VALVES

The flow curve of a valve-tester has a great influence on the performa nce of a valve. Usually the flow curve of the aorta is used. However, the mitral valve flow curve differs greatly from the flow curve of the aortic valve. It varies with the pulse rate and is further changed in patients with certain heart diseases. To investigate the different mi tral flow conditions, ultrasonic flow curves from patients with a mech anical artificial mitral valve were analyzed. The curves show that a m itral valve prosthesis has not only to work under physiological flow c onditions, but also in pathologically deviant flows. According to thes e results three different characteristic flow curves were selected and used to test several valves with a computer controlled valve-tester T he mean diastolic pressure difference and the whole closing behavior w ere influenced by the flow curve; and the differences in energy losses were particularly great. This indicates that the flow curve must be a djusted appropriately.