A CASE OF RIGHT CORONARY ARTERY ATRESIA WITH DOMINANT LEFT CIRCUMFLEX CORONARY ARTERY – SINGLE LEFT CORONARY ARTERY OR CORONARY OSTIAL ATRESIA?

Coronary artery anomalies are uncommon and are frequently detected incidentally during coronary angiography or computed tomography coronary angiography (CTCA). Congenital coronary ostial stenosis or atresia and single coronary artery are particularly rare entities and may pose a diagnostic dilemma because of overlapping imaging features. We report a case of a 74-year-old woman who presented with intermittent, non-exertional chest tightness and underwent CTCA for pre-operative cardiac assessment. Imaging demonstrated an atretic right coronary artery with non-visualisation of its distal segment. The left circumflex artery was dominant and continued along the left atrioventricular groove into the right atrioventricular groove, supplying the right coronary artery territory. Mild non-obstructive atherosclerotic plaques were present in the left anterior descending and left circumflex arteries. No significant myocardial ischemia or structural cardiac abnormality was identified. This case highlights the challenge of differentiating a single coronary artery variant from congenital or acquired right coronary ostial atresia on CTCA. Recognition of key anatomical features is essential, as accurate classification has important implications for prognosis and clinical management. CTCA provides excellent spatial resolution for non-invasive evaluation of coronary artery anomalies, allowing precise anatomical delineation. Given the patient’s mild symptoms and absence of significant coronary obstruction, conservative medical management was adopted.