True congenital atresia of the left main coronary ostium: delayed presentation.

Congenital atresia of the left main coronary ostium is a rare coronary anomaly presenting in adulthood. A 48-year-old man presented with unstable angina. Coronary angiography showed an absent left coronary ostium with a super-dominant right coronary artery retrogradely filling the left system. Computed tomography-angiography with 3-dimensional reconstruction confirmed the absence of the left main coronary artery. In view of ongoing chest pain, the patient was offered coronary artery bypass surgery. Total arterial revascularization was performed with a left internal mammary artery-left radial artery Y-graft.