The impact of different geometric assumption of mitral annulus on the assessment of mitral regurgitation volume by Doppler method

Abstract

Background: Mitral regurgitation volume (MRvol) by quantitative pulsed Doppler (QPD) method previously recommended suffers from geometric assumption error because of circular geometric assumption of mitral annulus (MA). Therefore, the aim of this study was to evaluate the impact of different geometric assumption of MA on the assessment of MRvol by two-dimensional transthoracic echocardiographic QPD method. Methods: This study included 88 patients with varying degrees of mitral regurgitation (MR). The MRvol was evaluated by QPD method using circular or ellipse geometric assumption of MA. MRvol derived from effective regurgitant orifice area by real time three-dimensional echocardiography (RT3DE) multiplied by MR velocity-time integral was used as reference method. Results: Assumption of a circular geometry of MA, QPD-MA A4C and QPD-MA PLAX overestimated the MRvol by a mean difference of 10.4 ml (P < 0.0001) and 22.5 ml (P < 0.0001) compared with RT3DE. Assumption of an ellipse geometry of MA, there was no significant difference of MRvol (mean difference = 1.7 ml, P = 0.0844) between the QPD-MA A4C + A2C and the RT3DE. Conclusions: Assuming that the MA was circular geometry previously recommended, the MRvol by QPD-MA A4C was overestimated compared with the reference method. However, assuming that the MA was ellipse geometry, the MRvol by the QPD-MA A4C + A2C has no significant difference with the reference method.