Left main coronary artery originating from the proper sinus but with acute angulation and an intramural course, leading to critical stenosis.

Because of the variety of their anatomy and clinical implications, coronary anomalies tend to confuse many observers. Recently, our group and other investigators have proposed that only 1 specific type of anomaly, by means of a specific mechanism, is able to cause both symptoms of myocardial ischemia and sudden death. This anomaly is known as anomalous origin of a coronary artery from the opposite sinus of Valsalva, with intramural course (ACAOS). Its defining pathophysiologic feature is that the proximal section of the ectopic artery has an intramural course, which leads to variable degrees of functional obstruction. Herein, we describe an unusual, previously unreported coronary anomaly: a "normal origin" of the left main coronary artery from the left sinus of Valsalva that resulted in progressive, critical ischemia. The proximal few millimeters of this artery were intramural, embedded into the aortic-sinus wall, and laterally compressed. Therefore, this anomaly may be regarded also as "ACAOS of the left coronary artery without an ectopic origin." Angiography and intravascular ultrasonography revealed a variable degree of obstruction without intimal thickening and, likely, without spasm. Surgical repair, including ostioplasty, completely relieved the patient's clinical symptoms.