Beyond Magnetic Resonance Angiography in Anomalous Aortic Origin of the Coronary Arteries: Additive Value of Late Gadolinium Enhancement

Purpose: Anomalous aortic origin of the coronary arteries (AAOCA) is a common cause of sudden cardiac death (SCD) in young athletes. The prevalence, pathophysiology, and optimal method of risk stratifying AAOCA are unknown. Coronary magnetic resonance angiography (MRA) has been shown to reliably define anatomical features. However, studies evaluating current methods of detecting inducible or chronic ischemia in patients with AAOCA are lacking. We present our institutional experience utilizing late gadolinium enhancement (LGE) as an adjunct to exertional symptoms, exercise stress testing (EST), and single-photon emission computed tomography (SPECT) for risk stratifying high-risk AAOCA. Methods: A retrospective review was conducted of all patients referred for evaluation of possible AAOCA by cardiac magnetic resonance imaging (CMR) between January 2011 and December 2017. Patients with high-risk coronary anatomy were included; patients with complex congenital heart disease were excluded. High-risk AAOCA was defined as the presence of interarterial or intramural features. We assessed the utility of risk stratifying high-risk AAOCA by LGE, SPECT and exertional symptoms. Validity of SPECT in detecting affected coronary vascular territories was also examined. Chi-square test of independence was used for statistical analysis. Results: There were 74 patients evaluated for possible AAOCA (median age 14.3 years; 69% male); 40 met high-risk inclusion criteria (34 right, 6 left). SPECT was performed in 33 patients, and EST in 36 patients. Exertional symptoms were present in 11 patients. One patient with aborted SCD had subepicardial LGE, most consistent with myocarditis. No additional patients had baseline ventricular dysfunction or LGE findings on CMR. Risk stratification by exertional symptoms or coronary variant revealed no significant correlation to any markers of ischemia. Furthermore, SPECT was predominantly negative (70%), and 3 of 10 positive results did not correlate with the affected coronary vascular territory. Conclusions: Our study demonstrates the difficulties in utilizing common techniques for risk stratification in patients with AAOCA. While coronary MRA has been shown to reliably assess coronary anatomy, CMR-derived LGE had no additive value in this cohort, and SPECT had a high false positive rate. A larger multicenter study including the utility of stress CMR would be beneficial in this patient population.