Anomalous left circumflex coronary artery: "normal" variant of uncertain clinical and pathologic significance.

Anomalous origin of the left circumflex artery from the aorta is generally viewed as a benign coronary arterial anomaly. Three such cases are reported in which the anomalous artery was totally occluded. Although coronary atherosclerosis was present in all three cases, the proximal segment of the anomalous circumflex vessel was particularly severely affected in each patient. Two patients had a myocardial infarct in the distribution of the aberrant vessel. Accurate angiographic diagnosis is needed before cardiac surgery is performed, whether for valve replacement or myocardial revascularization, because this variant may be less benign than one believed.