In up to 0.07% of the general population, the right anterior cardinal vein obliterates and the left remains open, creating an absent right superior caval vein and a persistent left superior caval vein. Absent right superior caval vein is associated with additional congenital heart disease in about half the patients. We wished to study the consequences of absent right superior caval vein as an incidental finding on prenatal ultrasonic malformation screening.

This is a retrospective case series study of all foetuses diagnosed with absent right superior caval vein at the national referral hospital, Rigshospitalet, Denmark, from 2009 to 2012.

In total, five cases of absent right superior caval vein were reviewed. No significant associated cardiac, extra-cardiac, or genetic anomalies were found. Postnatal echocardiographies confirmed the diagnosis and there were no postnatal complications. All children were found to have healthy hearts at follow-up.

In all cases, the findings proved to be a benign condition with no clinical manifestations or complications. Although isolated absent right superior caval vein does not seem to affect the outcome, associated anomalies may be serious. Absent right superior caval vein should, therefore, prompt a search for additional malformations. Furthermore, the diagnosis of an isolated absent right superior caval vein is important, because knowledge of the anomaly can prevent future problems when invasive procedures are necessary.