A semiquantitative method based on proximal convergence zone to estimate the severity of the mitral regurgitation: design and clinical application.

Abstract

The analysis of the mitral regurgitation using the proximal isovelocity surface area method has not been extended to clinical practice because of its complexity. Our objective was to design and validate a simplified semi-quantitative method based on proximal isovelocity surface area to assess the severity of mitral regurgitation. We studied 58 patients with mitral regurgitation. We found a good correlation between the angiographic grade of mitral regurgitation and the parameters derived from proximal isovelocity surface area: maximal regurgitant flow, regurgitant orifice and volume (r: 0.90 to 0.92, P<0.05). The values of maximal regurgitant flow that best predicted the grades of angiographic severity (I--IV) were estimated by regurgitant orifice curves, with cut points of 16, 56 and 160ml.s(-1)kappa(p)=0.92). Considering that maximal regurgitant flow only depends on the radius of proximal isovelocity surface area and the velocity of aliasing used, we constructed a nomogram with the previously described limits. Twenty-four new patients were studied using this nomogram and angiography. An excellent degree of agreement was found (kappa(p)=0.93). The inter- and intraobserver variability showed a kappa(p)=0.89 and 0.91, respectively. This nomogram allows a fast semi-quantitative estimation of the grade of MR, feasible and highly correlative with the invasive methods.