Anomalous left brachiocephalic vein: important vascular anomaly concomitant with congenital anomalies and heart diseases.

BACKGROUND: Anomalous left brachiocephalic vein (ALBCV) is a rare and less known systemic venous anomaly. Infrequently, this vein takes an abnormal course and passes to the right behind or beneath the aortic arch to create the superior vena cava (SVC). Its incidence was reported much higher in patients with congenital heart disease especially in conotruncal and aortic arch anomalies. It could be misdiagnosed with normal or abnormal mediastinal structures. It also could make complication during surgeries or invasive strategies. Previously, this anatomical finding has been reported in case reports and there are just few studies evaluating these patients as a group to find other abnormalities MATERIALS AND METHODS: We conducted a retrospective, multicentre study between 2008 and 2014 at three institutions. We reviewed thoracic computed tomography angiography of 1372 patients referred to these centres. The diagnosis of ALBCV was confirmed by an expert radiologist and the imagings were reassessed to identify new cases and concomitant anomalies. We analysed the imagings' details and measured the prevalence of each anomaly.

RESULTS: Among the 22 cases of ALBCV, 12 (54.5%) and 10 (45.4%) patients were males and females, respectively, with median age of 12.5 years. Tetralogy of Fallot (TOF) was considered as a most concomitant anomaly with ALBCV (54.5%). Two patients had associated atrial septal defect (ASD) and defined as pentalogy of Fallot. Right-sided aortic arc (RSAA) was detected in 12 (54.5%) patients; mirror image was found in 5 of them. Pure ventricular septal defect or pulmonary stenosis without TOF was recognised in 4 patients. Three cases had isolated overriding aorta (13.6%). In 3 patients, we could find patent ductus arteriosus (13.6%). In 2 (9%) patients, abdominal haemangioma was incidentally diagnosed. Aberrant left retrotracheal subclavian artery was detected in 1 (4.5%) patient. One patient only had isolated ALBCV (4.5%).

CONCLUSIONS: In our study, ALBCV was frequently seen in association with other congenital anomalies. mostly TOF and RSAA. In patients with pulmonary hypoplasia or aplasia, some parts of lung's blood supply were provided by abnormal aorto-pulmonary connections. For a radiologist, it is important to differentiate this anomaly in cross-sectional imaging from persistent left SVC, partial anomalous pulmonary veins return and an enlarged lymph node. Detection of ALBCV could draw the attention to the more serious heart disease and in isolated forms prevented further evaluations.