A rare case of a coronary vascular ring arising from an anomalous single coronary artery.

We report a rare finding of a pair of coronary artery anomalies noted on computed tomography coronary angiography in an asymptomatic 75-year-old woman. This patient had a single coronary artery that bifurcated into a left main coronary artery (with an unfavorable interarterial course) and a right coronary artery. This gave rise to a vascular ring around the atrioventricular groove. We propose that the presence of this vascular ring may have been protective against the potentially ischemic course of the single-origin coronary artery passing between the aorta and pulmonary trunk.