absent ductus venosus
Agenesis of the ductus venosus (ADV) is a rare fetal vascular anomaly.
According to the data obtained from the screening tests performed at 11-14 weeks of pregnancy, its incidence is reported to be 1/2500 .
In a large case series, Acherman et al. defined five drainage patterns in absent ductus venosus:
- the umbilical vein is connected to the systemic venous circulation through the portal sinus
- via an abnormal venous channel from the portal sinus to the right atrium
- presumably via hepatic sinusoids to the hepatic veins
- the umbilical vein bypasses the portal sinus and the liver and connects to the systemic venous circulation via an abnormal venous channel (case 2)
- from the umbilical vein to the right iliac vein (case 1)
- development of hydrops fetalis
- fetal aneuploidy
- focal liver necrosis and calcification
- chromosomal anomalies, e.g. Turner syndrome
- non-aneupliod syndromic anomalies, e.g. Noonan syndrome
- non-syndromic anomalies, e.g. congenital cardiac anomalies
Treatment and prognosis
The prognosis of fetuses with absent ductus venosus diagnosed at 11-13 weeks of gestation depends on the measurement of nuchal translucency thickness, being poor if the thickness is increased and good if it is normal .