Noninvasive diagnosis of complications of the mitral bioprosthesis.

The echophonocardiographic diagnoses of valvular and paravalvular insufficiency, calcific stenosis, and thrombolic occlusion of the stent-mounted aortic homograft or heterograft in the mitral position are described. Paravalvular and valvular insufficiency were associated with apical systolic murmurs which decreased in intensity after amyl nitrite inhalation and with echocardiograms which showed initial diastolic slopes of the stents in excess of the normal range (1.9 to 3.3 cm. per second). In clinically improved and stable patients, amyl nitrite inhalation resulted in increased intensity of the commonly heard systolic ejection type murmur at the left sternal border and echocardiographic evidence of further narrowing of the outflow tract measured between the interventricular septum and the anterior portion of the stent. Calcific homograpft stenosis was associated with a decreased diastolic stent slope (0.4 cm. per second) and increased echo density from the tissue leaflets. Thrombus formation on the sewing ring caused fatal inflow occlusion in 2 patients. The condition was characterized by an echocardiogram showing decreased ratio of internal-to-external stent diameter, 0.47 (normal range 0.56 to 0.74), decreased diastolic stent slope, and decreased leaflet excursion.