Assessment and follow-up of patients with aortic regurgitation by an updated Doppler echocardiographic measurement of the regurgitant fraction in the aortic arch

Abstract

The purpose of this study was to determine the value and limitations of an updated Doppler echocardiographic measurement of the aortic regurgitant fraction derived from the comparison of forward and reverse flows in the aortic arch. The method was based on the improvements in sampling and displaying Doppler frequencies and blood velocities provided by pulsed-emission, two-dimensional location, and spectral analysis and on an account for variations of aortic diameter through an M mode record of the aortic arch. Relevant statistical comparisons were performed between simultaneous noninvasive and invasive determinations of the regurgitant fraction in a group of 30 patients with aortic regurgitation (group I) and between simultaneous noninvasive and invasive measurements of variations of the regurgitant fraction induced by atrial pacing or vasodilator administration in 12 patients of this group. The two basal determinations were closely correlated (r = .90). The invasive regurgitant fraction ranged from 0% to 80%. The standard error of the Doppler estimate was 8.8% in group I as a whole and was only 6% in a subgroup of 20 patients with a high systolic aortic flow pattern, defined as both peak velocity above 0.8 m/sec and duration of systolic flow above 0.24 sec. This pattern was present in almost all (19/22) patients in whom the aortic regurgitation was more than moderate by invasive criterion (regurgitant fraction above 40%). The standard error of the Doppler estimate of variations of the regurgitant fraction was only 6.6%. Among 100 additional patients without aortic regurgitation (group II), only 12 had no pandiastolic reverse flow in the arch, and their regurgitation was always mild at aortographic examination. Among 100 patients with aortic regurgitation (group III) four had a pandiastolic reverse flow in the arch and each had a left-to-right stunt issued from the aorta at the invasive study. The false-negative and false-positive diagnoses of aortic regurgitation on aortic arch records were all corrected by the Doppler sampling beneath the aortic valve. Provided that left ventricular sampling confirms the regurgitation and that aortic sampling displays the high systolic flow pattern, the Doppler measurement of the regurgitant fraction in the aortic arch is remarkably suited to the assessment and follow-up of patients with aortic regurgitation.