Evaluation of obstructive characteristics of mitral disc valve implants with ultrasound doppler techniques.

Ten adult patients with mitral disc valve implants have been examined on the catheterization table. Non-invasive ultrasound Doppler data, pulmonary artery wedge pressure and left ventricular pressure were recorded simultaneously. The cardiac output was determined with the direct Fick method. The effective valve area was taken as a measure of the flow obstruction in the disc valve implants. This area was calculated from the ultrasound data and the cardiac output as well as from the manometric data and the cardiac output. The resulting two sets of areas demonstrated a linear correlation coefficient of 0.86. The effective valve areas calculated from the ultrasound data were reasonable when compared with the results of in vitro studies of disc valve performance and demonstrated good agreement with the findings of other investigators.