Coronary anomalies include anomalous aortic origin of a coro- nary artery (AAOCA), coronary fistula, and myocardial bridge. Many congenital coronary abnormalities have a benign outcome. In contrast, natural history studies of anomalous coronary artery from the PA (particularly anomalous left coronary artery from the PA) suggest poor outcome in untreated patients; similar natural history studies are lacking regarding untreated patients with AAOCA, but other evidence raises concern. See Table 34 and Figure 5 for a diagnostic and treatment algorithm for AAOCA. Assessment of the risk of SCD in patients with AAOCA and of the role of AAOCA in causing ische- mia or symptoms is difficult because available data do not adequately capture the clinical spectrum of these anomalies. Autopsy series are available that help de- scribe the anomalies found in patients who suffered SCD contrasted to other causes of death.S4.4.7-1 S4.4.7-5 There are surgical case series that describe findings before operation, operative anatomy and postopera- There are imaging studies describing the anatomy and potential pathophysio- logical abnormalities associated with AAOCA.S4.4.7-6, There are surgical series describing im- provement in symptoms after operation.S4.4.7-6 S4.4.7-8 There are surveys and registries that describe the heterogeneous management strategies applied to What is lacking are data prov- ing that any particular management strategy prevents SCD. As a consequence, decisions regarding whether surgery is necessary or exercise restriction or medi- cal therapy might be beneficial are all based on syn- thesizing limited data and applying to an individual patient. Clinicians commonly extrapolate to assist in medical decision-making, but the consequences of Table 34. 