Duplication of the umbilical vein along with an extrahepatic, intrathoracic right umbilical vein in the setting of Taussig-Bing anomaly with atrioventricular septal defect

The incidence of persistent right umbilical vein (PRUV) is approximately 2 per 1000 pregnancies, with cases utilizing extrahepatic and intrathoracic routes to connect to the superior vena cava (SVC) being notably rarer. The case in question involved an 18-week fetus presenting with concurrent cardiac anomalies: D-transposition of the great arteries (TGA) classified as Taussig-Bing anomaly and atrioventricular septal defect (AVSD), highlighting the uniqueness of the presentation. A second-trimester ultrasound, including echocardiographic assessment, identified Taussig-Bing anomaly, AVSD, pulmonary stenosis (PS), and a right-sided stomach position with a left-sided umbilical vein exhibiting a PRUV with an anomalous trajectory towards the SVC. These findings indicate a rare association of multiple congenital malformations. The right-sided stomach raised concerns for potential cardiosplenic syndromes, such as heterotaxy. Additionally, two vessels observed posterior to the heart in the four-chamber view raised suspicion for inferior vena cava (IVC) interruption, possibly suggesting an azygos vein formation. However, a thorough assessment of the IVC confirmed normal anatomy, with the posterior vessel identified as the PRUV.