Critical update and discussion of the prevalence, nature, mechanisms of action, and treatment options in potentially serious coronary anomalies.

As widely discussed in recent literature, coronary artery anomalies only occasionally lead to potentially serious myocardial ischemic events. The most important group of coronary anomalies has been called anomalous coronary artery origin from an abnormal sinus or a site in the ascending aorta (ACAOS). Only some cases of right- or left-sided intramural-course ACAOS (R-ACAOS-IM or L-ACAOS-IM) can potentially cause significant symptoms or sudden cardiac death, typically during exertion in athletes. After an ACAOS-IM case is qualitatively identified, it is necessary to establish the severity of associated stenosis (which is always present to some degree in ACAOS-IM). The 3 stages of a comprehensive diagnostic process are: 1. initial screening of high-risk populations (young elite athletes, optimally by use of magnetic resonance imaging [MRI]) to identify the prevalence of similar cases in large populations (the denominator of any risk calculation); 2. evaluating symptoms (chest pain, syncope, or sudden death) and performing stress testing; 3. in patients found to carry ACAOS-IM, evaluating the severity of coronary obstruction by intravascular ultrasonography, which is an objective, definitive, and quantifying imaging modality for this condition, essential in selected carriers of such anomalies. The possible treatment alternatives are discussed and updated.