Abnormal first-trimester ductus venosus blood flow: a marker of cardiac defects in fetuses with normal karyotype and nuchal translucency.

OBJECTIVE: To evaluate the independent contribution of ductus venosus (DV) blood flow assessment at 11-14 weeks' gestation to the prediction of congenital heart defects (CHD) in chromosomally normal fetuses, irrespective of the value of the nuchal translucency thickness (NT).

METHODS: During a 4-year period, all singleton pregnancies from 11 + 0 to 13 + 6 weeks' gestation were scanned for NT and DV blood flow in a tertiary center. Abnormal DV blood flow was defined as either absent or reversed flow during atrial contraction (AR-DV). Fetal echocardiography was performed in all cases with either NT > 99(th) percentile or AR-DV. Follow-up was assessed by postnatal examination or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS: A total of 6120 pregnancies were scanned at a median gestational age of 12 weeks, and 45 cases of CHD were detected. AR-DV was found in 206 fetuses, of which 145 (70.4%) had a normal karyotype. Among fetuses with AR-DV and normal karyotype, 11 cases of CHD were diagnosed, giving a sensitivity of 24.4%, a positive predictive value of 7.6% and an odds ratio of 9.8. Increased NT (> 99(th) centile) was present in 55 of the 145 (37.9%) cases with AR-DV and normal karyotype, and in 6/11 (54.5%) of those with CHD. Thus, the group of 90 fetuses with abnormal DV blood flow and normal NT contained five cases of CHD, for a sensitivity of 11.1%, a positive predictive value of 5.5% and an odds ratio of 8.5. Right-heart anomalies were predominant in those cases with isolated AR-DV (4/5), but no specific CHD pattern was found in those with increased NT. The detection rate of CHD by the combined use of increased NT and/or AR-DV in the first trimester improved from 28.9% (13/45) to 40.0% (18/45).

CONCLUSIONS: In experienced hands, abnormal DV blood flow in the first trimester is an independent predictor of CHD and should constitute an indication for early echocardiography. In this study, the use of DV blood flow assessment increased early detection of CHD by 11% with respect to the use of NT measurement alone.