Critical assessment of two-dimensional echocardiographic estimation of the mitral valve area in rheumatic mitral valve disease: calcific deposits in the valve as a major determinant of the accuracy of the method.

Abstract

The accuracy of two-dimensional echocardiographic estimation of the mitral valve area (MVA) and the effects which the morphological features of the valve (degree of stenosis, coexistent regurgitation, extent of calcific deposits) exert on the approximation of such a measurement have been evaluated. In 29 patients, who underwent surgical replacement of a rheumatic mitral valve, correlation was assessed between the echocardiographic values of MVA and the anatomical ones measured on excised valves by means of a sizer set to detect area differences up to 0.1 cm2 Though the correlation obtained was statistically significant (P <0.001) the percentage deviation (δ%) between the two series of measurements was appreciable (29.38 ± 20.14%, mean ± 1 s.d.). The degree of stenosis and the presence or absence of regurgitation did not affect δ%. Only the amount of calcific deposits, evaluated from the radiographs of the excised valves, influenced the discrepancy between the two methods, δ% being significantly higher (P < 0.05) in the calcified valves than in the not or minimally calcified ones. Though the two-dimensional echocardiographic estimates ofM VA in rheumatic mitral valve disease are correlated with the anatomical area, their predictive value in the estimation of the true orifice size is poor in the individual patient, in view of the large discrepancy between the echocardiographic and anatomical measurements found in our study.