Observer variability in the quantitation of Doppler color flow jet areas for mitral aortic regurgitation

Early studies using Doppler color flow imaging have suggested that measurement of the regurgitant jet area provides information regarding the severity of valvular insufficiency. This study was performed to assess the observer variability of mitral and aortic regurgitant jet area measurements using the Doppler color technique. Color Doppler recordings from 45 patients were reviewed: 23 patients had aortic regurgitation and 22 had mitral regurgitation. To assess interobserver variability, the largest definable mitral regurgitant jets from three cardiac cycles were independently chosen and measured by planimetry by two observers who were unaware of other patient information. Measurements were repeated by both observers at a separate time to obtain intraobserver data. Videotapes from 23 patients with aortic regurgitation were similarly analyzed. Each observer measured the isovolumic aortic jet (before mitral valve opening) and the maximal aortic regurgitant jet (at any time during diastole) using computer-assisted planimetry. Both intraobserver and interobserver correlations were excellent for mitral regurgitant jet areas (r = 0.97 and r = 0.93, respectively). The intraobserver correlation for isovolumic aortic regurgitant jet was r = 0.73; the interobserver correlation for this measurement was only fair (r = 0.57). For the maximal aortic regurgitant jet area, intraobserver correlation was good (r = 0.86) and interobserver correlation was fair (r = 0.72). These findings suggest that intraobserver and interobserver reproducibility are acceptable for the measurement of mitral regurgitant jet area. However, the measurement of aortic regurgitant jet areas results in significant observer differences that appear to be related to problems with slow sampling rates for the measurement of isovolumic aortic regurgitation and to difficulties in separating mitral inflow from aortic regurgitation for the maximal Jet.