QUANTIFYING AORTIC REGURGITATION BY USING THE COLOR DOPPLER-IMAGED VENA CONTRACTA - A CHRONIC ANIMAL-MODEL STUDY

Background The aim of the present study was to evaluate the accuracy o f determining aortic effective regurgitant orifice area (EROA) and aor tic regurgitant volume by using the color Doppler-imaged vena contract a (CDVC). Methods and Results Twenty-nine hemodynamically different st ates were obtained pharmacologically in eight sheep with surgically in duced aortic regurgitation. Instantaneous regurgitant flow rates (RFRs ) were obtained with aortic and pulmonary electromagnetic flowmeters ( EFMs), and aortic EROAs were determined from EFM RFRs divided by conti nuous wave Doppler velocities. Color Doppler-derived EROAs were estima ted by measuring the maximal diameters of the CDVC. Peak and mean RFRs and regurgitant volumes per beat were calculated from vena contracta area continuous wave diastolic Doppler velocity curves. Peak EFM-deriv ed RFRs varied from 1.8 to 13.6 (6.3 +/- 3.2) L/min (range [mean +/- S D]), mean RFRs varied from 0.7 to 4.9 (2.7 +/- 1.3) L/min, regurgitant volumes per beat varied from 7.0 to 48.0 (26.9 +/- 12.2) mL/beat, and the regurgitant fractions varied from 23% to 78% (55 +/- 16%). EROAs determined by using CDVC measurements correlated well with reference E ROAs obtained by using the EFM method (r = .91, SEE = 0.07 cm(2)). Exc ellent correlations and agreements between peak and mean RFR and regur gitant volumes per beat as determined by Doppler echocardiography and EFM were also demonstrated (r = .95 to .96). Conclusions Our study ind icates that the CDVC method can be used to quantify both aortic EROAs and regurgitant flow rates.