Ductus venosus Doppler in fetuses with cardiac defects and increased nuchal translucency thickness

To examine the possible role of Doppler ultrasound assessment of ductus venosus blood flow in screening for major cardiac defects in chromosomally normal fetuses with increased nuchal translucency (NT) thickness at 11 + 0 to 13 + 6 weeks' gestation.

Ductus venosus blood flow velocity waveforms were obtained immediately before chorionic villus sampling for fetal karyotyping in fetuses with NT thickness of 3.5 mm or more at 11 + 0 to 13 + 6 weeks of gestation. In the chromosomally normal group fetal echocardiography was performed by a specialist pediatric cardiologist at 11 + 0 to 13 + 6 weeks and/or 18-22 weeks' gestation.

Major cardiac defects were diagnosed in 16 (8.4%) of the 191 chromosomally normal fetuses. Reversed or absent flow in the ductus venosus during atrial contraction was observed in 11 of the 16 (68.8%) fetuses with cardiac defects and in 40 of the 175 (22.9%) with no cardiac defects. Multivariate analysis demonstrated that the prevalence of an abnormal A-wave in the ductus venosus in fetuses without major cardiac defects increased with fetal NT thickness (odds ratio (OR), 1.463; 95% CI, 1.183-1.809; P < 0.0001) but in those with cardiac defects it did not change significantly with NT thickness (OR, 2.054; 95% CI, 0.573-7.360; P = 0.269). The likelihood ratio for a major cardiac defect when the ductus venosus flow was abnormal decreased with fetal NT thickness from 4.58 at NT 3.5 mm to 2.47 for NT 5.5 mm, and the likelihood ratio when the ductus venosus flow was normal increased from 0.37 at NT 3.5 mm to 0.43 for NT 5.5 mm.

In chromosomally normal fetuses with increased NT the finding of an absent or reversed A-wave in the ductus venosus is associated with a three-fold increase in the likelihood of a major cardiac defect, whereas the finding of normal ductal flow is associated with a halving in risk for such defects.