Measurement of mitral valve area in mitral stenosis: four echocardiographic methods compared with direct measurement of anatomic orifices.

OBJECTIVES: This study sought to compare the mitral valve areas of patients with rheumatic mitral valve stenoses as determined by means of four echocardiographic and Doppler methods with those obtained by direct anatomic measurements. BACKGROUND: There has been no systemic comparison between Doppler-determined valve areas and the true anatomic orifice in a single cohort. METHODS: In 30 patients with mitral stenosis, the mitral valve areas determined by two-dimensional echocardiographic planimetry, pressure half-time, flow convergence region and flow area were compared with the values directly measured on the corresponding excised specimen by means of a custom-built sizer. RESULTS: The correlation coefficient was r = 0.95 (SE 0.06, p < 0.0001) for two-dimensional planimetry; r = 0.80 (SE 0.09, p < 0.0001) for pressure half-time; r = 0.87 (SE 0.09, p < 0.0001) for flow convergence region; and r = 0.54 (SD 0.1, p < 0.002) for flow area. Two-dimensional echocardiographic planimetry, pressure half-time, flow convergence region and flow area overestimated the actual anatomic orifice by > 0.3 cm2 in 2, 1, 6 and 0 patients, respectively, and underestimated it by > 0.3 cm2 in 0, 4, 1 and 8 patients, respectively. CONCLUSIONS: Mitral valve areas determined by two-dimensional planimetry, pressure half-time and proximal flow convergence region reliably correlated with size of the anatomic orifice. The flow area method provided a less reliable correlation.