[Pulsed echo-Doppler evaluation of regurgitant fraction in mitral valve insufficiency]

The aim of this study was to evaluate the validity of Doppler echocardiographic evaluation of the regurgitant fraction in pure mitral insufficiency. The Doppler echocardiographic measurement of systemic flow was made at the level of the aortic ring, and the mitral flow by the method of integration of instantaneous flow proposed by Touche. In a preliminary study, we demonstrated a close correlation between forward aortic and mitral flow in 20 normal subjects (r = 0.94; SD = 0.31 l/mn; y = 0.98 x -0.004). We then studied a group of 38 patients with pure isolated mitral regurgitation. Five patients were excluded because of the poor quality of the echocardiographic documents. The hemodynamic regurgitant fraction was determined by measuring pulmonary flow by thermodilution and the left ventricular outflow by digitised angiography. The average Doppler and hemodynamic regurgitant fractions were 46.6 +/- 18% and 42 +/- 17% respectively. There was a close correlation between the Doppler and hemodynamic values (r = 0.91; SD = 7.8%; y = 0.97 x + 5.7). The correlations were also good between Doppler regurgitant fraction and the four angiographic grades of regurgitation (r = 0.88). A statistically significant difference was observed between the Doppler regurgitant fractions of Grades I and II and of Grades III and IV (p less than 0.001). In addition, the ratio of mitral VTI/aortic VTI gave a useful index of regurgitation in pure mitral insufficiency. When the ratio was greater than 1.3 the regurgitant fraction was over 40% with a sensitivity of 79% and a specificity of 86%. Finally, this study shows that pure, isolated mitral regurgitation can be evaluated by Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)