Use of New PISA Methods to Calculate the Mitral Valve Area in Mitral Stenosis

Our study aimed to compare the validity of five noninvasive methods used in the calculation of the mitral valve area. We studied 34 patients with rheumatic mitral stenosis. Mitral valve area was calculated for all patients using planimetric method, pressure-half time method, PISA, and corrected PISA methods and new mathematical method. The calculated average mitral valve areas were similar for all techniques (139±0.06 cm2, 141±0.05 cm2, 142±0.08 cm2, respectively) (p<0.01). The most relevant correlation to the planimetry was obtained with the pressure-half time method (r=0.94). The other was between the planimetry and the corrected PISA method (r=0.92). These correlations were followed by the new mathematical method (r=0.88) and the PISA method (r=0.85). In view of the anatomy of the valvular and subvalvular apparatus, since the assumption of PISA as a half-spherical area is inaccurate and the assumption as a horizontally cut funnel-shaped area is more appropriate as in our mathematical model, this new method may have correlated better with the planimetry than the PISA method. In conclusion, all five techniques can be used in assessing mitral valve area in patients with mitral stenosis. The new method is proposed as an alternative to determine the mitral valve area.