Reproducibility of stand-alone continuous-wave Doppler recordings of aortic flow velocity across bioprosthetic valves.
Continuous-wave Doppler spectra of aortic flow velocity were recorded in duplicate in 20 consecutive patients with aortic porcine valves by 1 technician and 3 occasions: initially and 1 week and 1 month later. The highest maximal aortic velocity recorded from at least 2 transducer locations was taken from 5 consecutive beats that did not vary. The 120 tracings were coded and read by 1 observer. In blinded fashion, 20 records were read twice and 26 were read by 2 interpreters. Variability was calculated from the square root of pooled variances and expressed in meters per second and also related to the mean velocity and expressed as percent coefficient of variation for the following categories: interpretive [intraobserver +/- 0.019 (0.8%), interobserver +/- 0.071 (2.7%)], technical [duplication +/- 0.048 (1.9%)], temporal/biologic [+/- 0.125 (5.0%)]. Doppler measurements of aortic velocity can achieve excellent reproducibility by maintaining constant technique. With a methodologic variability of +/- 2%, the variability associated with the passage of time was significantly different at +/- 5% and was a result of fluctuations in the physiology of a few subjects. Thus, the technique can distinguish small method errors from minor drifts of the biology and, by implication, detect the onset of bioprosthetic degeneration.
D000368:Aged; D001021:Aortic Valve / Q000503:physiopathology*; D001705:Bioprosthesis; D001783:Blood Flow Velocity; D004452:Echocardiography; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors