Comparison of mitral valve area by pressure half-time and proximal isovelocity surface area method in patients with mitral stenosis: effect of net atrioventricular compliance

The aim of this study was to test the hypothesis that, unlike calculation of the mitral valve area (MVA) with the pressure half-time method (PHT), the proximal isovelocity surface area method (PISA) is not affected by changes in net atrioventricular compliance (Cn). Methods and results We studied 51 patients with mitral stenosis (MS) from two centres. MVA was assessed with the PISA (MVAPISA), PHT (MVAPHT), and planimetry (MVAPLN, serving as the gold standard) method. Cn was calculated with a previously vali- dated equation using 2D echocardiography. MVAPISA closely correlated with MVAPLN (r ¼ 0.96, P , 0.0001), while MVAPHT and MVAPLN showed a weaker but still good correlation (r ¼ 0.69, P , 0.0001). The correlation between MVAPHT and MVAPLN for patients with Cn between 4 and 6 mL/mmHg (considered to be normal) was excellent (r ¼ 0.93, P , 0.0001), but that for patients with Cn of less than 4 or more than 6 mL/mmHg was not as good (r ¼ 0.64, P , 0.0001). Importantly, a significant inverse correlation was detected between the percentage difference among MVAPHT ,M VAPLN, and Cn (r ¼ 20.77, P , 0.0001), but the line of fit was nearly flat for the percentage differ- ence among MVAPISA ,M VAPLN, and Cn (r ¼ 0.1, P ¼ 0.388). Conclusion MVA calculated with both the PISA and PHT methods correlated well with MVA calculated with the planimetry method. However, the PISA rather than PHT is recommended for patients with MS and extreme Cn values because PISA, unlike PHT, is not affected by changes in Cn.