Zero coronary calcium despite severe left anterior descending artery stenosis in a high take-off single coronary artery with prepulmonic left main course – A clinical case

A high-take-off single coronary artery is a rare congenital coronary anomaly that may complicate coronary angiography and percutaneous coronary intervention. A 35-year-old man presented with anterior ST-segment elevation myocardial infarction (STEMI). Initial coronary angiography was limited by difficulty in selective engaging the anomalously located coronary ostium, resulting in inadequate contrast opacification. Coronary computed tomography angiography (CCTA) subsequently demonstrated a single high-take-off coronary ostium arising from the ascending aorta, with a prepulmonic course of the left main coronary artery. Despite a coronary artery calcium score of 0, severe approximately 80% proximal left anterior descending artery (LAD) stenosis was identified (CAD-RADS 4A). Repeat invasive coronary angiography demonstrated 95% subtotal proximal LAD occlusion with a hazy appearance suggestive of active thrombus. Primary PCI with two overlapping drug-eluting stents restored TIMI grade 3 fl ow without procedural complications. This case highlights the value of CCTA in defining anomalous coronary anatomy and demonstrates that a calcium score of 0 does not exclude clinically significant obstructive coronary disease.