A Rare Coexistence of Coronary and Aortic Arch Anomalies in a Case of Complex Congenital Heart Disease and Their Clinical Impact

Coronary artery anomalies are uncommon in congenital heart disease (CHD), with left anterior descending (LAD) and left circumflex (LCx) variants being particularly rare and clinically relevant. Their coexistence with complex aortic arch anomalies is exceptional and poses major diagnostic and surgical challenges. We report a 19-year-old female with complex CHD post-Fontan surgery with worsening dyspnea. Computed tomography (CT) angiography demonstrated a patent Fontan circuit with separate origins of the right coronary artery (RCA), LAD, and LCx; anomalous anterior cusp origins of the RCA and LAD; a shepherd’s crook course of the LAD; and a retroaortic LCx arising from the posterior cusp. An unreported aortic arch configuration consisting of truncus bicaroticus with aberrant right subclavian artery and segmental right common carotid artery agenesis was also identified. This case underscores the indispensable role of CT angiography in comprehensive anatomical delineation and procedural planning, as such anomalies, though incidental, substantially increase the risk of cannulation failure, surgical injury, and ischemic complications in surgically modified CHD.