Introduction
The left brachiocephalic vein usually courses obliquely downward, passing anterior to the aortic arch and its own brachiocephalic branches. It joins the right brachiocephalic vein to form superior caval vein. Rarely, the left brachiocephalic vein takes an anomalous course. It extends lateral to the aortic arch, enters the gap between the extrapericardial aorta and the right pulmonary artery, and crosses the mediastinum posterior to the ascending aorta and anterior to trachea. It then joins the superior caval vein between the azygous vein and superior cavoatrial junction.1-5 This pattern is usually described as the retroaortic left brachiocephalic vein (Figures 1A-1F).1-6
It is a rare anomaly, first described by Kerschner in 1888.7 The first angiographic description was provided by Roberts and associates in 1951, with Cloez and associates recognizing it echocardiographically in 1982. Webb and associates described computed tomographic findings, again in 1982, while Fujimoto and associates showed magnetic resonance findings in 1992.1,8-10 In 1992, Takada and associates described a double circumaortic left brachiocephalic vein.11
As far as we are aware, around 250 cases have now been reported since 1980.1-80 When found in isolation, the anomalous course is of no clinical importance. Recognition of in the setting of associated lesions, in contrast, is important. This is because it can be mistaken for a persistent left superior caval vein, or a vertical vein in the setting of totally anomalous pulmonary venous connection. In this review, we evaluated all clinical, as well as necropsy, studies describing this venous anomaly with and without coexisting congenital heart diseases. We have emphasized its potential implications for the cardiac surgeon.