Early outcomes of children with univentricular circulation undergoing Fontan surgery: the EuroFontan registry.

BACKGROUND AND AIMS The Fontan operation and its modifications have transformed the management of children with functional single ventricle physiology. While outcomes have improved, peri-operative complications remain common. This study aimed to assess early outcomes and complications following Fontan completion in a large international European cohort. METHODS The EuroFontan registry is a multicentre retrospective study involving 21 congenital heart disease and transplant centres across Europe. Data were collected on patients who underwent Fontan surgery from January 1990 to January 2023. Analyses focused on the most recent 15-year period. A composite early adverse outcome (death within 30 days or in-hospital, low cardiac output syndrome, stroke, or Fontan takedown) was used. Predictors were assessed using multivariable mixed-effects logistic regression, with centre included as a random effect. Missing data were handled using multiple imputation with Rubin's rules, and sensitivity analyses were performed to assess robustness. RESULTS Of 3510 patients, this analysis focused on 2075 individuals from the past 15 years, with a median age of 4.2 [interquartile range 3.2-6.2] years at Fontan completion. Early mortality was 1.0% (95% confidence interval .66%-1.54%). The composite adverse outcome occurred in 5.1% (95% confidence interval 4.2%-6.1%). On multivariable analysis, morphology other than tricuspid atresia was the only significant predictor of the composite outcome (odds ratio 2.2, 95% confidence interval 1.21-3.99, P = .01). CONCLUSIONS Fontan surgery has evolved and, in contemporary practice, has low peri-operative morbidity and mortality. Morphology other than tricuspid atresia was associated with increased risk of early adverse outcomes, highlighting the importance of pre-operative risk stratification.