[Calculation of the regurgitation fraction in mitral insufficiency by Doppler echocardiography using a study of the zone of flow convergence].

The aim of this study was to propose a new method for calculating the regurgitation fraction of mitral insufficiency by the proximal isovelocity surface area (PISA) method and to compare it with the value of the catheter regurgitation fraction. Thirty-five patients (21 men and 14 women) aged 59 +/- 13 years with isolated mitral insufficiency were studied. Analysis of the proximal isovelocity surface area enabled calculation of an instantaneous maximum regurgitant flow, surface of the regurgitant orifice and the regurgitant volume. The regurgitant fraction was calculated by dividing the regurgitant volume by the sum of the regurgitant volume and aortic stroke volume measured by Doppler echocardiography. These parameters were compared with the corresponding catheter data and the angiographic grade of mitral insufficiency. The echocardiographic and catheter studies were performed within 1.7 +/- 1.2 days. There was a statistically significant correlation between the instantaneous maximum regurgitant flow calculated by the PISA method and the catheter regurgitant flow (r = 0.88; p = 0.0001); between the regurgitant volume calculated by the PISA method and the catheter regurgitant volume (r = 0.85; p = 0.0001) and the regurgitation fraction calculated by the PISA method and the catheter regurgitant fraction (r = 0.82; p = 0.0001). A regurgitant fraction by the PISA method of > 45% corresponded to severe mitral regurgitation (> or = angiographic grade 3 and/or a catheter regurgitant fraction > or = 50%) with a sensitivity of 88% and a specificity of 100%. The PISA method should form part or routine quantification of mitral insufficiency.