Anomalous course of the left brachiocephalic vein

An anomalous course of the left brachiocephalic vein beneath the aortic arch was identified in 7 patients undergoing surgical repair of congenital cardiac malformations.Six of these patients had the morphologic features of tetralogy of Fallot including severe obstruction to the right ventricular outflow tract and a right aortic arch.A review of the literature reveals this to be an uncommon anomaly.When it is present, however, it is frequently associated with a ventricular septal defect, sually, the left brachiocephalic (innominate) vein U courses anterior to the aortic arch and its brachiocephalic branches and joins the right brachiocephalic vein to form the superior caval vein (Fig 1).Rarely, the left brachiocephalic vein has an anomalous course beneath the aortic arch, where it then joins the superior caval vein between the azygos vein and the superior cavoatrial junction.Kershner [l] first described this anomaly in 1888, and it has been reported in the literature only occasionally since then.In this report we describe a series of patients diagnosed at the time of congenital heart operation, review the current literature, and comment on the potential clinical implications of this anomaly.