Anomalous Origin of the Right Coronary Artery from the Left Anterior Descending Artery in adult with Single Left Coronary Artery and ST-Elevation Myocardial Infarction

Single coronary artery (SCA) is a rare anomaly, with a reported prevalence of only 0.024%-0.066% among patients undergoing routine coronary angiography. Most SCA is found only incidentally in conventional coronary angiography or coronary computed tomography angiography. Some subgroups of SCA can lead to angina pectoris, acute myocardial infarction, or even sudden cardiac death. We present the extremely unusual case of a patient with anteroseptal ST elevation myocardial infarction (STEMI) who was also diagnosed with SCA upon further evaluation. A 52-year-old man with a history of smoking and hypertension was referred to our hospital with an anterior ST-elevation myocardial infarction. Coronary angiography was performed immediately and demonstrated a single coronary artery arising from the left coronary sinus with an anomalous right coronary artery originating as a separate branch from the left anterior descending artery (LAD). The culprit lesion was subtotal occlusion of the proximal segment of LAD, which was recanalized and treated with drug-eluting stent angioplasty. A coronary computed tomography angiography (CCTA) showed an anomalous right coronary artery (RCA) that arose from the proximal LAD, which coursed anteriorly to the pulmonary artery to reach the territory normally served by the RCA. The distal left circumflex (LCX) coronary artery gave rise to the posterior descending and posterolateral branches. In conclussion, the RCA originating from the (LAD) is an extremely rare coronary anomaly; in such cases, the RCA arises from the proximal or mid-portion of the LAD artery. So far, only 40 cases have been reported. Enhanced awareness of congenital cardiac anomalies may help guide management.