Case Image: Superdominant right coronary artery and left anterior descending artery arising from the right coronary sinus: a rare coronary artery anomaly.

A 78-year-old woman with no cardiovascular risk factors was admitted to the clinic with non-ST-segment elevation myocardial infarction. Baseline electrocardiogram revealed diffuse ST segment depressions in the anterior leads, and transthoracic echocardiogram demonstrated regional hypokinesia of the inferoposterior wall of the left ventricle with an estimated left ventricular ejection fraction of 55%. Laboratory tests were normal except for an elevated level of cardiac troponin I (2.46 ng/mL; reference: 0.000–0.016 ng/mL). Early coronary angiography revealed a blunt left sinus of Valsalva, a single superdominant right coronary artery (RCA) originating from the usual location with significant atherosclerotic stenosis in the mid-proximal segment, and a left anterior descending artery (LAD) arising from the right sinus of Valsalva (Figures A, B and Videos 1, 2*). To confirm the blunt left sinus of Valsalva, aortography was performed (Figure C and Video 3*). The RCA was selectively cannulated with a right Mach 1 6-F guide catheter (Boston Scientific Corp., Marlborough, MA, USA) and percutaneous coronary intervention was successfully performed without any complication (Figures D, E). To rule out potential ectopic origin of the left main coronary artery, a coronary computed tomography angiography was performed. The patient was discharged on the fifth day without any cardiac sequelae. At 1month and 6-month follow-ups, she was free of any cardiac complaints. Coronary artery anomalies (CAAs) are rare, and typically incidentally diagnosed during routine cardiac catheterization; the incidence is reported as 0.2% to 1.3% in angiographic series and 0.3% in autopsy series. The coronary artery anatomy of this patient corresponded to the R-I variant of the Lipton classification, which is defined as the superdominant coronary artery arising from the right coronary sinus and following the course of a normal RCA. It is considered to be one of the rarest CAAs, with an incidence of 0.0008%, along with the LAD originating from the right coronary sinus, which is another extremely rare CAA. 77