Coronary-Bronchial Artery Fistulas: Pathophysiology, Multimodality Imaging, and Contemporary Management

Coronary-bronchial artery fistulas (CBAFs) represent a rare subset of coronary artery fistulas characterised by an abnormal communication between an epicardial coronary artery and the bronchial arterial circulation. Although historically considered incidental findings, the widespread use of multimodality cardiovascular imaging-particularly coronary computed tomography angiography-has led to increasing recognition of these anomalies in contemporary clinical practice. The clinical significance of CBAFs varies widely and depends primarily on fistula size, shunt magnitude, and associated cardiopulmonary conditions. While many small fistulas remain asymptomatic, larger or haemodynamically significant lesions may result in myocardial ischaemia due to coronary steal, ventricular remodelling, pulmonary manifestations such as haemoptysis, and aneurysmal degeneration of the fistulous tract. A comprehensive evaluation typically requires an integrated multimodality approach combining anatomical imaging, functional ischaemia testing, and, in selected cases, invasive haemodynamic assessment. Management strategies range from conservative surveillance in small asymptomatic fistulas to percutaneous or surgical closure in symptomatic or haemodynamically significant lesions. This review provides an updated overview of the epidemiology, pathophysiology, diagnostic evaluation, and management of CBAFs. Particular emphasis is placed on size-based clinical stratification, multimodality imaging strategies, and contemporary therapeutic approaches, with the aim of offering a practical framework for the diagnosis and longitudinal management of patients with this uncommon but clinically relevant coronary anomaly.