Imaging-based identification of high-risk anomalous aortic origin of coronary arteries (AAOCA) patients

Background although assessment of inducible myocardial ischemia in patients with Anomalous Aortic Origin of the Coronary Arteries (AAOCA) is generally recommended, there is no clear consensus regarding the most appropriate stress test. In a previous study from our centre, we demonstrated that, in a cohort of 100 AAOCA patients, 14% exhibited perfusion abnormalities during dobutamine stress cardiac magnetic resonance (dsCMR) consistent with inducible myocardial ischemia. Anomalous origin of the left coronary artery (p < 0.001) and the presence of an intramural course (IM) (p = 0.049) were significantly associated with inducible ischemia. In 9% of cases LGE with an ischemic pattern was found in the AAOCA territory; these patients were older [p = 0.001] and had a history of acute coronary syndrome (p < 0.001). However, no computed tomography (CT) parameters have been studied in relation to inducible myocardial ischemia on dsCMR to better identify patients who require further investigation, particularly within the high-risk subgroup of right AAOCA (R-AAOCA) with an intramural course (IM). Purpose a) To determine which CT characteristics are associated with reduced fractional flow reserve (FFR) during hyperaemia in patients with R-AAOCA and IM; b) To evaluate whether these parameters are associated with inducible myocardial ischemia. Methods This single-centre study included two cohorts of patients, both with R-AAOCA and IM. In the first cohort, all patients underwent CT and invasive coronary angiography with evaluation of FFR during hyperaemia. In the second cohort, all patients underwent dsCMR and CT according to the internal AAOCA evaluation protocol for risk stratification. CT analysis was performed using convolutional neural networks. Results The cohort of R-AAOCA patients with IM included 42 individuals, of whom 17% exhibited hyperaemic FFR < 0.80. Among the CT parameters, only the minimum diameter measured was found to be associated with positive FFR (1.37 ± 0.17 vs. 1.64 ± 0.35 mm; p = 0.020). For the minimum area measured, a trend toward significance was observed (2.26 ± 0.42 vs. 4.5 ± 2.2 mm²; p = 0.053). ROC curve analysis of the minimum diameter yielded an AUC of 0.752 [0.583–0.921] (p = 0.038). The best cut-off identified using the Youden index was 1.59 mm. In a larger cohort of R-AAOCA patients with IM including 61 patients, 15% exhibited perfusion abnormalities on dsCMR consistent with inducible myocardial ischemia. In this cohort, a minimum diameter measured at CT < 1.59 mm was associated with inducible myocardial ischemia on dsCMR (27% vs. 6%; p = 0.044). Conclusions In the high-risk subgroup of patients with R-AAOCA and IM, a minimal intramural diameter < 1.59 mm was associated with hyperaemic FFR < 0.80. Notably, this anatomical parameter was also associated with inducible myocardial ischemia on dsCMR, supporting its potential role in identifying patients at higher functional risk.