Assessing the severity of mitral stenosis: Variability between noninvasiveand invasive measurements in patients with symptomatic mitral valve stenosis

Background This study evaluated the correlation and variability between non invasive and invasive measures of mitral stenosis severity before and after balloon mitral commissurotomy (BMC) in a large group of patients with symp tomatic mitral stenosis. Factors related to variability between measurement s were determined. Methods The Doppler transmitral gradient, Doppler half-time valve area, and 2-dimensional echocardiographic (2D) mitral valve area (MVA) were measured immediately before and 1 day after BMC in 272 consecutive patients with mi tral stenosis and compared with their respective measures during cardiac ca theterization. Results The correlation coefficient for the comparison of noninvasive and i nvasive measurements of the transmitral gradient was 0.63 before BMC and 0. 60 after the procedure; for 2D versus Gorlin-derived MVA, 0.39 and 0.57 res pectively; and for Doppler half-time versus Gorlin-derived MVA, 0.31 and 0. 18, respectively. A large degree of variability in the measurement of MVA w as present among the 3 techniques before BMC and increased after BMC. Befor e BMC, for the comparison of 2D and Gorlin-derived MVA, variables predictiv e of the discrepancy were age, echocardiographic score, transmitral gradien t during catheterization, and cardiac index. For the comparison of Doppler half-time versus Gorlin-derived MVA, age, heart rate during cardiac cathete rization and echocardiography, cardiac output and left ventricular end-dias tolic pressure predicted the difference between the 2 measures. Conclusions In symptomatic patients with mitral stenosis, there is signific ant variability between noninvasive and invasive measures of mitral stenosi s severity despite careful, reproducible measurements. The difference betwe en noninvasive and invasive measures of MVA before BMC is strongly related to cardiac output.