Value of Proximal Isovelocity Surface Area Method in Calculation of Mitral Valve Area in Patients with Mitral Stenosis

Proximal isovelocity surface area method (PISA) is a new technique based on the continuity principle, and its use in the measurement of orifice areas is still being developed. The aim of our study is to estimate the value of that method in the measurement of mitral valve area (MV A) in cases with mitral valve stenosis, to compare its accuracy with traditional echocardiographic methods, planimetry and Doppler pressure half-time and to investigate the factors which affect MV A measurements. MV As of 30 consecutive patients with mitral valve stenosis (mean age 43±14-25 female, 5 male) referred to echocardiography laboratory were obtained with planimetry, Doppler pressure half-time and PISA and their results were compared by coefficient of correlation (r). Patients were also evaluated due to their image quality, presence of additional factors such as atrial fibrillation, mitral regurgitation and aortic regurgitation. MV As measured by PISA are closely correlated to classical echocardiographic methods, especially to planimetry. Coefficients of correlation between that method and planimetry and Doppler were r=0.86 and r=0.68 respectively. The most important problem in the estimation of MV A by PISA was the accurate determination of the aliasing radius (r). When the latter was less than 1 cm PISA results are not comparable to these of other methods. In the presence of atrial fibrillation, mitral regurgitation and aortic regurgitation, PISA was more comparable to planimetry which is a reliable method in these situations. However, in cases with inadequate image qualities, planimetry lost its reliability, and measurements of PISA was not affected its results were closer to Doppler pressure half-time.