Functional–anatomic integration by CCTA and exercise SPECT in adults with anomalous aortic origin of a coronary artery

Background: Anomalous aortic origin of a coronary artery (AAOCA) may be associated with exertional ischemia, ventricular arrhythmias, and adverse outcomes. The relationship between high-risk anatomic features and functional consequences remains incompletely defined. Coronary computed tomography angiography (CCTA) and exercise-stress myocardial perfusion scintigraphy (SPECT) present as complementary modalities for integrated assessment of anatomy, ischemia, and arrhythmias. Methods: We retrospectively studied consecutive adults with AAOCA undergoing CCTA and exercise-stress <^>99mTc-SPECT between 2010 and 2025 at two centers. Inducible ischemia was defined as a summed difference score (SDS) >= 4. A composite endpoint (death, myocardial infarction, angina requiring evaluation, ventricular arrhythmias, or coronary revascularization) was assessed during follow-up. Discriminative performance of ECG, CCTA, SPECT, and combined imaging models was evaluated using ROC analysis. Results: Thirty-five patients (mean age 51 +/- 15 years; 89% men) were included. At least one high-risk CCTA feature was present in 60% of cases, and inducible ischemia occurred in 51%. An interarterial course was significantly associated with SPECT positivity (67% vs. 12%, p = 0.007). Ventricular arrhythmias during exercise were more frequent in SPECT-positive patients (50% vs. 13%, p = 0.03). During a median follow-up of 59 months, the combined CCTA+SPECT model showed the highest discrimination (AUC 0.76). Conclusions: Integrating CCTA with exercise-SPECT links high-risk anatomy to functional and arrhythmic manifestations and may improve risk stratification in adults with AAOCA.