Die Doppler-echokardiographische Quantifizierung des regurgitierenden Blutvolumens bei Patienten mit Mitralinsuffizienz

Summary The purpose of this study was to assess the accuracy and clinical utility of pulsed Doppler echocardiography in determining the regurgitant fraction in patients with pure mitral regurgitation. In 30 unselected consecutive patients with mitral regurgitation and in 20 patients without valvular heart disease pulsed Doppler echocardiography was performed to measure blood flow at the mitral and aortic valve. The regurgitant blood volume was calculated as the difference of the stroke volumes measured at the mitral and aortic valve. The regurgitant fraction was computed as regurgitant blood volume/mitral flow. By cardiac catheterization regurgitant blood volume and regurgitant fraction were obtained from the left ventricular angiographic stroke volume and the stroke volume measured by thermodilution. Five patients were excluded because of technically poor left ventricular angiograms. In 4 patients with mitral regurgitation measurement of the regurgitant blood volume and regurgitant fraction was impossible by Doppler because of poor ultrasound signal quality. In 21 patients with mitral regurgitation the correlations between the invasive and the Doppler measurements were significant (regurgitant blood volume:r=0.89, SEE=20.9 ml; regurgitant fraction:r=0.91, SEE=7.1%). However, the mean percent error of the regurgitant fraction measurement (12.0±11.6%) was smaller than of the regurgitant blood volume measurement (24.9±17.0%). In the control group the regurgitant blood volume ranged between –25.1 ml and 11.6 ml and the regurgitant fraction between –17.7% and 12.4%.Thus, pulsed Doppler echocardiography is clinically useful in determination of the regurgitant fraction in 84% of unselected adult patients with pure mitral regurgitation. The Doppler method is limited in the diagnosis and quantification of mild regurgitation. However, the method is more accurate in determining the regurgitant fraction than measuring the regurgitant blood volume.

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Abkürzungsverzeichnis MI Mitralinsuffizienz - RBV regurgitierendes Blutvolumen - RF Regurgitationsfraktion - SV_Angio angiographisch berechnetes Schlagvolumen - SV_Ao Doppler-echokardiographisch an der Aortenklappe gemessenes Schlagvolumen - SV_Mi Doppler-echokardiographisch an der Mitralklappe gemessenes Schlagvolumen - SV_Thermo mittels Thermodilution bestimmtes Schlagvolumen