Clinicians commonly extrapolate to assist in medical decision-making, but the consequences of Table 34. Factors That May Relate to the Clinical Importance of AAOCA and Risk of SCD Age AAOCA is more commonly invoked as the cause of SCD in patients <35 y of age than in patients >35 y of age, in whom atherosclerotic coronary disease becomes a more prevalent cause. However, death has been attributed to AAOCA in patients of all ages; there does not seem to be an age beyond which the AAOCA may not be relevant, even in the setting of atherosclerotic coronary disease and other concomitant conditions.S4.4.7-1,S4.4.7-2 Anatomy of coronary ostium and proximal coronary course Slit-like/fish-mouth-shaped orifice, acute angle takeoff, intramural course, interarterial course and hypoplasia of the proximal coronary artery have all been proposed as reasons for symptoms, ischemia and SCD in patients with AAOCA. The slit- like orifice is more commonly seen in anomalous right coronary artery arising from the left sinus. Each of these anatomic findings offers a pathophysiological mechanism for intermittent ischemia, particularly at times of high cardiac output and/or increased aortic wall tension, such as during exercise.S4.4.7-6,S4.4.7-9 S4.4.7-11 Anomalous origin Left coronary artery arising from the right cusp is less common than the right coronary artery arising from the left cusp but is more often found in autopsy series of SCD.S4.4.7-1,S4.4.7-3,S4.4.7-15 This suggests that anomalous origin of the left coronary artery from the right cusp is more likely to cause SCD than anomalous origin of the right coronary artery from the left cusp. This may be due either to anatomic features that make anomalous aortic origin of the left coronary artery prone to coronary compromise or because a larger proportion of myocardium is supplied by the left coronary artery, or both. 