Ductus venosus Doppler velocimetry in the prediction of acidemia at birth: which is the best parameter?
To evaluate the prediction of acidemia at birth using ductus venosus Doppler velocimetry and to determine the best parameter and cut-off values for this prediction in pregnancies complicated with placental insufficiency. Prospective cross-sectional study. Forty-seven patients with placental insufficiency managed in two Brazilian hospitals were submitted to ductus venosus Doppler velocimetry in the last 24 h before delivery. All pregnancies were singleton, at least 26 weeks of age and without structural or chromosomal anomalies. A ROC curve was calculated for each ductus venosus parameter (independent variable) and acidemia (dependent variable). A cut-off value was established. The McNemar test was used to compare the various parameters. The ductus venosus S, D and A peak velocities were not good predictors of acidemia at birth. Pulsatility Index for Veins (PIV) was a good predictor of acidemia (ROC curve area 0.79, p = 0.003), as well as S/A and (S - A)/S ratios (ROC curve area 0.818, p = 0.001). The cut-off values were PIV = 0.76, S/A = 2.67 and (S - A)/S = 0.63. In this high-risk population, angle-independent ductus venosus Doppler indexes were good predictors of birth acidemia. The S/A and (S - A)/S ratios and the ductus venosus PIV were statistically equivalent in this prediction.