Quantitative Assessment of Aortic Regurgitation by Continuous Wave Doppler Echocardiography

To evaluate the usefulness of continuous wave Doppler echocardiography in the quantitative assessment of aortic regurgitation, the aortic regurgitant flow velocity curves taken by continuous wave Doppler echocardiography were analyzed to develop indexes such as the peak velocity(PV), the deceleration slope(SLOPE) and the pressure half time(PHT) in 66 patients with aortic regurgitation.

The Doppler indexes were compared with the aortic regurgitation fraction(RF) obtained from gated radionuclide ventriculography in 33 patients without other valvular regurgitation, and were also compared with angiographic grading of aortic regurgitation in 47 patients who under went aortic angiography.

The results were as follows :

1) The deceleration slope and the pressure half time were correlated well with the regurgitation fraction measured by gated radionuclide ventriculography (r=0.68, -0.78).

2) The deceleration slope increased significantly with increasing angiographic grading (rade 1+vs.2+ ; 1.89±0.61m/sec vs.2.64±0.39, P<0.05, Grade 2+ vs.3+ ;2.64±0.39 vs. 4.37±1.35, P<0.01, but statistical singnificance was not found between Grade 3+ and 4+(4.73±1.35vs. 5.00±0.39, P<0.05).

3) The pressure half time decreased significantly with increasing angiographic grading (Grade 1+vs.2+ ; 0.61±0.16 sec vs. 0.49±0.08, p<0.05, Grade 2+ vs.3+ ; 0.49±0.08vs. 0.29±0.07, p<0.01), but statistical significance was not found between Grade 3+ and 4+ (0.29±0.07vs. 0.26±0.08, p>0.05), either.

4) The pressure half time was independent of aortic or mitral stenosis associated with aortic regurgitation.

5) The peak velocity had no significant relationshop with the regurgitation fraction by gated radionuclide ventriculography or angiographic grading by aortic angiography.

6) A PHT threshold of 400 msec separated mild (Grade 1+ and 2+)and severe (grade 3+ and 4+) aortic regurgitation with sensitivity of 88%, specificity of 96% and predictive value of 95%.

Therefore continuous wave Doppler echocardiographic method of anlyzing aoritc regurgitant flow velocity curve seemed to be useful for the noninvasive assessment of the severity of aortic regurgitation.