Single coronary artery anomaly with critical left anterior descending artery stenosis: A case of percutaneous intervention in congenital right coronary artery agenesis

Congenital agenesis of the right coronary artery (RCA) is a rare coronary anomaly that may coexist with atherosclerotic disease and pose unique diagnostic and therapeutic challenges. We present the case of a 60-year-old woman with a 10-year history of hypertension who experienced refractory nocturnal angina despite optimal medical therapy. Coronary computed tomography angiography (CCTA) revealed congenital RCA agenesis and critical (70–80 %) narrowing of the proximal-to-mid left anterior descending artery (LAD). Invasive angiography confirmed a single coronary artery system (L-I type classification) with severe (80–85 %) LAD stenosis. Percutaneous coronary intervention using a drug-eluting stent was performed to resolve symptoms and restore flow. At 6-month follow-up, the patient remained asymptomatic on guideline-directed therapy. This case underscores two critical points: (1) RCA agenesis exacerbates ischemia in atherosclerotic LAD disease by forcing the left coronary system to perfuse an expanded myocardial territory without collateral compensation, and (2) PCI offers targeted revascularization in anatomically complex congenital anomalies. Noninvasive imaging (CCTA) and invasive angiography remain pivotal for delineating the coronary anatomy and guiding intervention.