Congenital Coronary Artery Anomalies and Sudden Cardiac Death.

Coronary artery anomalies (CAAs) are a heterogeneous group of rare congenital diseases whose features and pathophysiological mechanisms are extremely variable, ranging from silent anomalies to sudden cardiac death (SCD) in the most severe cases. Although rare, congenital CAAs confer a high risk of myocardial ischemia and SCD, especially in young, previously "healthy" athletes during or immediately after vigorous exertion. Although some high-risk features that may lead to SCD have been identified, specific pathophysiological mechanisms related to SCD still remain poorly understood. When a CAA is incidentally diagnosed, optimal SCD risk stratification remains challenging, particularly in cases of anomalous aortic origin of a coronary artery arising from the opposite aortic sinus of Valsalva (ACAOS). In recent times, invasive imaging with intravascular ultrasound has gained a role in further identifying high-risk anatomic features; it has been integrated with traditional, non-invasive anatomic imaging evaluations, typically high-quality echocardiography, and cardiac magnetic resonance. Multidisciplinary programs and specific SCD risk scores should be developed in an endeavor to choose the right therapeutic approach, either clinical or interventional/surgical. Intravascular ultrasound is an extremely useful tool to evaluate vessel stenosis, even if prospective studies are still required to further validate this diagnostic strategy. In the present review, we aimed to analyze the pathophysiology and the clinical impact of ACAOS. We also summarized the predominant mechanisms for interference with normal coronary artery function, which might contribute to the onset of life-threatening arrhythmias and SCD.