Technical and biologic sources of variability in the mapping of aortic, mitral and tricuspid color flow jets

The quantification of valvular regurgitation by 2-dimensional Doppler imaging depends on identifying and minimizing variability. Aortic, mitral and tricuspid regurgitant jet areas were measured in 50 patients with sinus rhythm or atrial fibrillation to analyze the variables of reading error, valve site, jet size, rhythm and frame rate. One technician recorded jet velocities at 1 frame/cycle at a triggered interval after the electrocardiographic R wave and at frame rates of 7.5 and 15 frames/s. Jet areas from 5 consecutive beats were measured by planimetry by 1 observer. Coefficients of variation between and among groups were compared by analysis of variance; mean values were 14 to 22%. Jets grouped less than 2.5, 2.5 to 5 and greater than 5 cm2 showed the variance of small jets exceeding that of medium and large jets. Aortic regurgitant jets were largest and had smaller variance than mitral tricuspid jets. Variability due to atrial fibrillation and the slower frame rate was marginal. Intraobserver error was 4.3% and interobserver 15.4%. Thus, reproducing jet areas carries a minimum variability of 15% or higher, depending on jet size. Valve site could not be excluded as a separate variable. Comparative quantification is best limited to 1 observer.