Assessment of severity of mitral stenosis by echocardiographic leaflet separation.

Mitral valve area (MVA) determined at cardiac catheterization was compared with M mode echocardiographic measurements in 44 patients with mitral stenosis and no substantial mitral regurgitation. Despite statistically significant correlations, measurements of anterior leaflet motion, including rate of diastolic closure (EF slope) were not useful in predicting severity of stenosis. In contrast, maximal diastolic separation of anterior and posterior leaflets (SEP) was more closely correlated with MVA and appears to have some predictive value. Narrow separation was associated with severe mitral stenosis. Wide separation was associated with relatively mild stenosis. Intermediate values in 16 of 44 patients (36%) were not of predictive value. Recognizing this limitation, measurement of maximal diastolic mitral leaflet separation from M mode echocardiograms is proposed as a simple and useful method for assessing severity of mitral stenosis.