Occlusion of Residual Major Aortopulmonary Collaterals after Tetralogy of Fallot repair

Objectives The optimal management of residual major aortopulmonary collateral arteries (MAPCAs) following tetralogy of Fallot (TOF) repair remains controversial, particularly for small or borderline collateral vessels with uncertain hemodynamic significance. Whether all anatomically identified MAPCAs require prophylactic treatment is unclear. We sought to identify predictors of clinically significant residual MAPCAs and evaluate a physiology-guided selective transcatheter occlusion strategy. Methods This single-center retrospective cohort study included 60 patients with residual MAPCAs after complete TOF repair between January 2020 and December 2024. Patients were classified as having clinically significant residual MAPCAs (n=44) or non-significant residual MAPCAs (n=16) according to predefined physiological criteria, including persistent hypoxemia, pulmonary overcirculation, or hemodynamic compromise. Logistic regression and receiver-operating characteristic (ROC) analyses were performed to identify risk factors for clinically significant residual MAPCAs. In patients undergoing selective transcatheter occlusion, serial changes in oxygenation (PaO 2 /FiO 2 ) and tissue perfusion (serum lactate) were assessed before and after intervention. Results Patients who developed clinically significant residual MAPCAs had a greater number of MAPCAs (2.77±0.99 vs. 2.19±0.75, P =0.04) and larger maximum MAPCA diameter (3.02±0.91 vs. 2.44±0.91 mm, P =0.03). On univariable logistic regression analysis, both MAPCA number (OR: 2.19; 95% CI: 1.02–4.68; P =0.044) and maximum MAPCA diameter (OR: 2.15; 95% CI: 1.04–4.47; P =0.039) were associated with clinically significant residual MAPCAs. ROC analysis demonstrated modest discriminatory performance for MAPCA number (AUC: 0.67) and maximum diameter (AUC: 0.66), while a combined model improved prediction (AUC: 0.73). Optimal thresholds were ≥3 collateral vessels and maximum diameter ≥2.3 mm. Among the 44 patients who underwent selective transcatheter occlusion, median PaO 2 /FiO 2 increased from 171.7 to 244.9 mmHg ( P <0.001), whereas median lactate decreased from 1.60 to 1.02 mmol/L ( P <0.001) within 72 hours after intervention. Conclusions Not all residual MAPCAs following TOF repair become clinically significant. Greater collateral burden, reflected by increased MAPCA number and larger maximum diameter, is associated with a higher risk of clinically significant residual MAPCAs. A physiology-guided selective intervention strategy may enable identification of patients most likely to benefit from transcatheter occlusion while avoiding unnecessary prophylactic treatment in low-risk patients.