Outcomes of a Physiology-driven Extracardiac Fontan Strategy Incorporating Computational Fluid Dynamics: A Multicentre Study

OBJECTIVES: To report early and mid-term outcomes after extracardiac total cavopulmonary connection (EC-TCPC) and to evaluate prespecified subgroup comparisons, including calendar-time era effects (Era I vs Era II), selective fenestration, conduit-size categories, and late-era computational fluid dynamics (CFD)-guided conduit sizing. METHODS: This multicentre retrospective cohort study included 788 patients who underwent EC-TCPC between 2009 and 2025. Patients were prespecified into Era I (2009-2016) and Era II (2017-2025) for calendar-time comparisons reflecting evolving pathway-based management; the CFD-guided subcohort was restricted to late-era patients. Survival and event-related outcomes were analysed using Kaplan-Meier, competing-risk methods, and multivariable regression models. RESULTS: Early mortality was 2.4%. During a median follow-up of 8.2 years, overall survival was 97.2% at 1 year, 95.0% at 5 years, and 92.5% at 10 years. Freedom from major adverse events (MAEs) was 95.6%, 84.3%, and 75.3% at the same time points; the 10-year cumulative incidence of thromboembolism was 6.8% and of MAEs was 23.6%. In the prespecified era comparison, Era II was associated with shorter pleural drainage duration and lower rates of prolonged pleural effusion. Fenestrated patients showed higher event rates, consistent with confounding by indication. In Era II, CFD-guided conduit sizing was associated with improved early postoperative haemodynamics but did not independently reduce mid-term clinical events after adjustment. CONCLUSIONS: A physiology-driven extracardiac Fontan strategy provides low early mortality and preserved mid-term survival. Selective fenestration and geometry-aware conduit sizing support individualized surgical planning, whereas CFD-guided optimization should be regarded as a decision-support tool rather than a causal determinant of outcome.