[Determination of mitral valve area in patients with mitral stenosis by the flow convergence method: clinical application]

ABSTRACT

Classic echocardiographic methods to estimate mitral valve area [MVA] in the mitral stenosis [MS] has several limitations. Recently, the proximal isovelocity surface area [NSA] method has been shown lobe accurate for calculating MVA. This study sought to I] compare the accuracy of the PISA method to planimetry and Doppler pressure half-time [PHT] methods for echocardiographic estimation of MVA and 2] to evaluate the effect of atrial fibrillation [AF] and significant mitral regorgit4tjon [MR] on the accuracy of the NSA method. In 35 patients with rhumatic mitral stenosis, the mitral valve areas were determined by two-dimensional echocardiographic planimetry, pressure half-time and proximal flow convergence region. 19 patients had atrial fibrillation and 15 had associated mitral insufficiency a 2. The correlaton between PISA and planimetry areas was significant [r=0.83, p<.001]. The intraclass correlation coefficient was of 0.85 but with a large confidence interval [IC95%[0,68-0,91] explaining the significant underestimation of MVA by PISA method: 1,42 +/- 0,47 cm2 versus 1,56 +/- 0,41 cm2 respectively, [p<.001]-There was no signicant difference between PISA and PHT areas 1,42 +/- 0,47 cm2 versus I .43 +/- 0,46 cm. Underestimation of MVA par PISA method didn't have real clinical implication the sensibility of diagnosing severe MS [MVA negative predictive value of 83%. The correlation was good in patients with AF[r=0,84, p<.001] and with significant MR [r=0,83, p<.001]. The PISA method may be considered as reliable alternative method for estimation of the MVA in MS. Its accuracy is good in AF and associated MR