Status and Operative Outcomes of the Fontan Procedure Performed Beyond the First Decade of Life in the United States

<b>Background:</b> The Fontan operation is typically performed between two and five years-of-age in the United States. In this study, we analyzed the immediate outcomes of the Fontan operation performed beyond the first decade of life in the United States using a large administrative database. <b>Methods:</b> Kids' Inpatient Database (2003-2019) and Nationwide Inpatient Sample (2016-2021) datasets were used; 10,245 pediatric patients undergoing the Fontan operation were identified. The cohort was divided into: Traditional Fontan (TF, 2-5 years-of-age, n = 9,900) and Late Fontan (LF, ≥10 years-of-age, n = 345); Survivor and non-survivor status were based on discharge mortality. Demographic and clinical characteristics were assessed using standard statistical tests. <b>Results:</b> Only 3% of the Fontan procedures (n = 345/10,245) belonged to the LF group. LF was comprised predominantly of non-Caucasian ethnicity, higher socioeconomic class, and had a greater comorbidity burden. Heterotaxy syndrome and total anomalous pulmonary venous return were more common in the LF group as compared with hypoplastic left heart syndrome in the TF group. Patients in the LF group experienced higher postoperative morbidity but similar mortality and often required specialized healthcare post-discharge. Multivariate regression analysis revealed inferior survival among Fontan patients with ECMO use, atrioventricular septal defect, coagulopathy, acute kidney injury, infection, prolonged mechanical ventilation, but not age at Fontan. <b>Conclusion:</b> The proportion of patients undergoing LF compared with TF has decreased over time signalling a move toward earlier timing of the Fontan procedure. However, within the LF group, the number of LF patients has increased over time signifying an extended application of the Fontan operation. The patients in the LF group experienced greater postoperative morbidity with an associated higher baseline comorbidity but not short-term mortality after the Fontan procedure.