Noninvasive assessment of the Ionescu-Shiley pericardial xenograft in the mitral position: preliminary experience.

To establish noninvasive criteria for assessment of the Ionescu-Shiley pericardial xenograft in the mitral position, 29 patients with a normally functioning bioprosthesis were studied with m-mode echocardiography and phonocardiography. Two-dimensional echocardiograms were also obtained in ten of the patients. Although two-dimensional echocardiography provided simultaneous visualization of a greater number of stents and leaflets than the m-mode technique, the superior resolution of m-mode ultrasound permitted more detailed analyses of the xenograft's motion patterns. The anterior leaflet, recorded in all patients, had an average excursion of 1.2 +/- 0.22 cm. Leaflet thickness measured 4 mm or less. Coarse diastolic vibration of the anterior leaflet was recorded in two patients in the absence of both aortic insufficiency and prosthesis dysfunction. Ultrasonic estimates of prosthesis height and orifice diameter did not correlate with micrometer measurements, possibly due to the limited resolution of pulsed ultrasound in the presence of a highly reflective substance. Opening and closing of the pericardial leaflets were associated with the production of high frequency vibrations on the phonocardiogram. The potential usefulness and limitations of echocardiography for evaluating the function of bioprosthetic valves are discussed.