Late-Presenting Myocardial Infarction With Separate Anomalous Right-Sided Origins of the Left Anterior Descending and Circumflex Arteries: A Case Report

The clinical significance of an anomalous aortic origin of a coronary artery depends on the proximal course and ostial morphology, not on the ectopic origin alone, and coexisting acute myocardial infarction and multivessel atherosclerotic disease can make culprit assignment and revascularization difficult.A 79-yearold man was diagnosed with a late-presenting high-lateral ST elevation myocardial infarction while being treated for urinary sepsis.He had no ongoing chest pain.The electrocardiogram showed sinus rhythm with a premature atrial contraction (PAC), a negative T wave in aVL, and a flattened T wave in lead I, and cardiac troponin was 4850 ng/L.Transthoracic echocardiography showed regional wall-motion abnormalities and a left ventricular ejection fraction of 45% to 50%.Coronary angiography on day 3 demonstrated a left anterior descending artery arising from the right coronary ostial region with a severe proximal stenosis and a left circumflex artery arising separately from the right coronary sinus with a severe proximal stenosis.The right coronary artery had no significant stenosis.After clinical stabilization and heart team review, elective percutaneous coronary intervention of the proximal left circumflex artery was performed 34 days after diagnostic angiography.A 3.5 x 28 mm everolimus-eluting stent was implanted, and the procedural report documented no significant residual stenosis and final Thrombolysis in Myocardial Infarction grade 3 flow.Intervention on the anomalous left anterior descending artery was deferred pending coronary computed tomography angiography.This case separates the management of a severe atherosclerotic lesion from risk assessment of an anomalous coronary origin.Invasive angiography did not establish the proximal course of the left anterior descending artery, and an interarterial or intramural course cannot be inferred from its right-sided origin.Because no acute thrombus, pre-intervention flow grade, or definitive culprit lesion was documented, the circumflex artery should be described as the presumed infarct-related artery and the delayed procedure as staged revascularization.Further management of the left anterior descending artery requires cross-sectional anatomical imaging and individualized assessment of ischemia, viability, functional status, and procedural risk.