Congenital continuous retrograde basilar flow suggests type B interrupted aortic arch in a neonate: A case report

Reversed flow in the basilar artery can be acquired or congenital. Acquired reversed flow in the basilar artery can result from acute thrombosis of the basilar artery or retrograde vertebral artery flow. Congenital continuous retrograde basilar artery flow has not been described. We report a 2-day-old male presenting with hypocalcemic seizures which led us to obtain a Duplex echoencephalogram. An echocardiogram was subsequently ordered. In the coronal plane through the anterior fontanelle, retrograde flow was seen in the basilar artery and the right vertebral artery. In the axial plane through the temporal window, the flow was anteroposterior in both posterior communicating arteries. In the posterior cerebral arteries, the flow was retrograde in the P1 segment and anterograde in the P2 and P3 segments. An interrupted aortic arch was suspected. The echocardiogram showed a large perimembranous ventricular septal defect with bidirectional shunting, a hypoplastic and bicuspid aortic valve, an aortic arch interrupted between the left common carotid artery and the left subclavian artery (type B interrupted aortic arch), and a 5 mm patent ductus arteriosus with predominant right to left flow. Because of the patency of the large patent ductus arteriosus, our patient showed no sign of posterior circulation insufficiency. Prostaglandin E1 therapy was initiated immediately. Diagnosis of DiGeorge syndrome was proven. The infant underwent interrupted aortic arch repair and anterograde flow was established in the basilar artery. We conclude that congenital asymptomatic continuous retrograde flow in the basilar artery and left vertebral artery is a medical emergency as it implies the presence of type B interrupted aortic arch with large patent ductus arteriosus in a neonate.