Images in cardiovascular medicine. Right aortic arch with aberrant left innominate artery: a rare vascular ring.

Two children referred for cardiac imaging were found to have an unusual form of a vascular ring. The first patient was an asymptomatic 10-year-old girl with a membranous ventricular septal defect, prolapse of the right coronary aortic cusp, and mild aortic regurgitation. Her past history was notable for gastroesophageal reflux disease as an infant, which had prompted a barium swallow at a few months of age demonstrating a posterior compression defect on the esophagus. Detailed imaging of the thoracic vasculature was not pursued at the time given the lack of respiratory symptoms and resolution of her reflux. She was now referred for cardiac magnetic resonance imaging to quantify the degree of leftto-right shunt, aortic regurgitation, and left ventricular dilation. Cardiac magnetic resonance demonstrated a small membranous ventricular septal defect with pulmonary-to-systemic flow ratio of 1.2, mild aortic regurgitation, and a mildly dilated left ventricle with normal systolic function. A right aortic arch was incidentally detected with branches arising in the following order: proximal to distal: right common carotid artery, right subclavian artery, and left innominate artery. The left innominate artery originated from a prominent diverticulum of Kommerell off the proximal descending aorta and bifurcated into the left subclavian and left common carotid arteries (Figure 1). The trachea was not compressed. Given lack of symptoms and a normal pulmonary function test, no further intervention was recommended. The second patient was a 4-year-old boy with developmental delay, single kidney, and history of recurrent respiratory infections, asthma, and exercise intolerance. He had undergone a tonsillectomy. A barium swallow study obtained to evaluate noisy breathing and cough revealed posterior compression of the esophagus. Computed tomographic angiography of the chest demonstrated a right aortic arch with aberrant origin of the left innominate artery from a large diverticulum of Kommerell off the proximal descending aorta (Figure 2). The distal trachea and proximal right mainstem bronchus were compressed, and a left-sided ligamentum arteriosum completing a vascular ring was suspected. Given his respiratory symptoms and airway compression by the vascular ring, the patient underwent division of the vascular ring by video-assisted thoracoscopic surgery. Intraoperative findings confirmed the preoperative anatomic diagnoses, and the patient was discharged from the hospital the following day.