Anomalous Origin of the Right Coronary Artery from the Mid-Portion of the Left Anterior Descending Artery in a Patient with Single Left Coronary Artery: A Rare Coronary Artery Anomaly and Review of Literature

Origination of the right coronary artery (RCA) from the left anterior descending (LAD) artery is a case of single coronary artery. It is an extremely rare coronary artery abnormality and usually an incidental finding during coronary angiography. A 73-year-old man with a medical history of hypertension arrived with chest pain. Medical therapy started for ST elevated myocardial ischemia. During his diagnostic coronary angiogram, RCA was visualized as abnormally orientating from the mid-portion of LAD. A significant lesion in the proximal part of LAD, significant long lesion in the diagonal artery, and several stenoses in the obtuse marginal artery (OMA) were observed. To evaluate the course of RCA, coronary computed tomography angiography (coronary CTA) scan was performed. The patient underwent coronary artery bypass graft (CABG) for three vessels. He was discharged without any complication and no problems were detected in follow-up. In conclusion, if during classic angiography, RCA is not seen, the physician should keep in mind that RCA may originate from LAD. Current classification cannot exactly determine this anomaly and needs revision. When there is suspicion for coronary anomaly, performing coronary CTA can be helpful for better management and planning of therapy.