A METHOD FOR ESTIMATING AORTIC REGURGITANT EFFECTIVE ORIFICE AREA BY DIGITAL DOPPLER COLOR-FLOW MAPPING

Background and aims of the study: Although non-invasive assessment of the severity of aortic regurgitation (AR) is important, quantitative e valuation of AR can be difficult in clinical settings. Most Doppler ec hocardiographic methods have been compared with angiographic grading o f AR severity. However, while aortic angiography is used widely for gr ading AR severity, the method is only semi-quantitative. A computed se mi-automatic digital color Doppler method has recently been described fur calculating stroke volume and cardiac output. The study aim was to develop a method of evaluating AR severity by using a digital automat ed color Doppler method (ACM) along with continuous wave (CW) Doppler for estimating aortic regurgitant effective orifice area. Methods: A t otal of 22 different hemodynamic conditions were studied in six sheep. Regurgitant volumes (RV) were determined by electromagnetic flowmetry (EM) and by ACM. AR effective orifice areas (EOAs) were determined by dividing each of the RVs by the time integrals of the AR continuous w ave velocities. AR EOAs by ACM were compared with those obtained by EM and with other EM indices of regurgitant severity. ACM was accurate f or quantifying AR EOAs (r = 0.96). Results and conclusions: Calculated AR EOA correlated well with peak AR flow and regurgitant fraction by EM. The combined ACM/CW Doppler method can be useful for estimating no n-invasively the aortic regurgitant EOA and for evaluating the severit y of AR.