Fontan Surgery in a Middle-Income Country: Outcomes and Modifiable Factors Potentially Associated with Risk - A 13-Year Single-Center Experience.

INTRODUCTION: Functionally univentricular hearts represent nearly 10% of all congenital heart defects, and the Fontan procedure is used in the heterogeneous group of patients who have them. Although early mortality after the Fontan procedure has declined internationally, data from middle-income countries remain scarce. METHODS: This is a single-center retrospective observational study made through a review of the medical records of all pediatric patients who underwent the Fontan procedure from 2007 to 2020 in a public cardiac surgery referral center in Brazil. RESULTS: Fontan procedure with an extracardiac conduit was performed in 78 children (52.6% female), predominantly for tricuspid atresia (55.1%), at a mean age of 12.1 ± 3.2 years. Preoperative oxygen saturation averaged 78.6 (± 7.4)%. Thirty-day mortality was 13.0%. Mortality decreased from 22.9% before 2015 to 4.8% after 2015 (P = 0.037), concurrent with yearly increase in surgical volume and a rise in operating-room extubation rates (from 2.9% to 47.6%, P = 0.001). One in five patients presented with malnutrition or low body weight. In the multivariate analysis, we found a hazard ratio of 65.05 (95% confidence interval: 7.923 - 534.1; P = 0.0001) for in-hospital mortality associated with postoperative acute kidney injury. CONCLUSIONS: Patients underwent the Fontan procedure at a relatively late age. Mortality decreased over time alongside increased surgical volume and operating-room extubation rates. Nutritional status emerged as a potentially modifiable risk factor, whereas postoperative acute kidney injury was a strong independent predictor of in-hospital mortality, underscoring the critical impact of perioperative care.