Left Common Carotid Artery Isolation in a Newborn With Tetralogy of Fallot and DiGeorge Syndrome
A 2.8-kg newborn girl was referred to our hospital for tetralogy of Fallot with a right aortic arch. ECG failed to provide a clear anatomic definition of the pulmonary blood supply. Cardiac catheterization disclosed a right aortic arch giving rise to 4 separate branches in the following sequence: right common carotid artery, right vertebral artery, right subclavian artery, and aberrant left subclavian artery (Figure 1). An isolated left common carotid artery, draining into the left pulmonary artery, was visualized by retrograde filling after selective injection into the right common carotid artery (Figure 2). Such a rare anomaly creates a left-to-right shunt at the arterial level, which becomes more significant when the pulmonary artery pressure lowers because of spontaneous or surgical right ductal closure. Isolation of the common carotid artery occurs only when the homolateral subclavian artery is aberrant so that the innominate artery cannot be formed.
A bilateral patent ductus arteriosus connected the aortic isthmus to the right pulmonary artery and the isolated vessel to the left pulmonary artery. The main pulmonary artery and its branches were confirmed to be moderately and diffusely hypoplastic. Anomalous origin of the left anterior descending coronary artery from the right coronary artery was visualized.
Via median sternotomy (Figure 3), the baby underwent aortic arch implantation of the isolated left carotid artery and 3-mm polytetrafluoroethylene systemic-to-pulmonary shunt interposition between the ascending aorta and the left pulmonary artery (Figure 4). Complete repair was deferred because of the coronary anomaly and the small size of the pulmonary arteries. The thymic gland was absent, thus supporting the clinical findings typical of DiGeorge syndrome. The patient survived the operation and is currently awaiting complete repair.