Mitral prosthesis malfunction. Comparative Doppler echocardiographic studies of mitral prostheses before and after replacement.

To assess the influence of mitral prosthesis malfunction on various Doppler echocardiographic indexes, we studied the changes in the peak mitral flow velocity during early diastolic filling phase (Vmax), the mean transprosthesis pressure drop from the simplified Bernoulli equation, the mitral valve area by the pressure half-time method, and the left ventricular isovolumic relaxation time in 15 patients before and after replacement of the malfunctioning mitral prosthesis using continuous wave Doppler echocardiography. Examination of the 15 replaced prostheses revealed a torn or perforated leaflet in 12 valves and a sewing ring dehiscence in one valve. Additional restricted leaflet motion (classified as mild obstruction) was seen in three of these 13 valves. In the remaining two valves, severe prosthesis obstruction was noted. Changes in the Doppler indexes between the preoperative and postoperative study were present in all patients regarding Vmax (mean, 2.2 +/- 0.3 versus 1.6 +/- 0.2 m/sec; p less than 0....