Myocardial Ischemia Secondary to Anomalous Origin of Left Anterior Descending Coronary Artery: A Case Report and Literature Review

BACKGROUND Coronary artery anomalies (CAAs) are rare congenital conditions, with an incidence of approximately 0.01-0.03%. While often asymptomatic and discovered incidentally, certain variants carry serious prognostic implications. Among these, an anomalous left anterior descending (LAD) artery arising from the right coronary artery (RCA) with an inter-arterial course between the aorta and pulmonary artery is considered malignant due to its association with myocardial ischemia and sudden cardiac death, particularly in young adults. Early recognition and tailored management are therefore essential. CASE REPORT We describe the case of a 37-year-old man with a background of dyslipidemia, heavy smoking, and illicit drug use who presented with recurrent chest pain and suspected acute coronary syndrome. Electrocardiography revealed anteroseptal ST-segment elevation, although initial troponin was negative. Coronary angiography demonstrated an anomalous LAD originating from the RCA, with myocardial bridging at the mid-segment. Computed tomography coronary angiography confirmed a malignant inter-arterial course. A submaximal stress SPECT perfusion study achieved 77% of target heart rate, reproducing chest pain and revealing a small, reversible perfusion defect in the anteroseptal wall, consistent with ischemia. Despite optimal medical therapy, the symptoms persisted. He underwent on-pump coronary artery bypass grafting (CABG), and his postoperative recovery was uneventful. CONCLUSIONS An anomalous LAD with a malignant course is a potentially life-threatening condition. Multimodality imaging, functional assessment, and definitive surgical revascularization are critical to preventing adverse outcomes. This case highlights the importance of considering coronary anomalies in patients with unexplained or recurrent chest pain.