A study of the diastolic flow velocity profile of the clinically uncomplicated mitral porcine bioprosthesis using an echo-doppler technique.

Pulsed Doppler echocardiography was performed in 17 subjects who had clinically uncomplicated porcine bioprosthesis in the mitral position. A positive initial diastolic flow wave was present in all patients; end-diastolic A waves were seen in the sinus rhythm of every patient. The peak of the diastolic wave was delayed when compared with the normals in our laboratory. This wave had clearly demarcated ascending, mid- and descending segments. When contrasted with normal subjects, the slope of the diastolic wave was mildly reduced in all patients. Fine to coarse indentations on the descending and mid-segments were seen in 15/17 (88%) of the patients. We conclude that the diastolic flow profile of the clinically uncomplicated mitral bioprosthesis resembles mild mitral stenosis. Reduced orifice size and/or the physical properties of the bioprosthesis are the likely mechanisms for these alterations.