Extracardiac Conduit vs. Lateral Tunnel: Exploring the Optimal Approach for the Fontan Procedure

Background: The Fontan procedure is an established surgical intervention for patients with single-ventricle physiology, with the Extracardiac Conduit (ECC) and Lateral Tunnel (LT) as the primary techniques. Recent studies have questioned the long-term outcomes associated with these two approaches, particularly regarding survival, Fontan failure, and adverse events such as arrhythmias. With increased life expectancy in Fontan patients, optimizing surgical choice and follow-up is crucial to minimize long-term complications. Objective: This study aimed to compare the long-term survival and clinical outcomes of ECC and LT techniques in Fontan patients, using propensity score matching to control for confounding factors and ensure robust outcome assessment. Materials and Methods: This retrospective, observational study included data from 3,300 patients from the EUROFONTAN registry, collected across 21 European centers. The cohort was divided into ECC (n = 3,010) and LT (n = 290) groups. Propensity score matching was applied to balance baseline characteristics between the groups. Primary outcomes included early and late mortality, Fontan failure, and adverse events, with additional analysis of factors like arrhythmia incidence and kidney failure. Results: In the propensity-matched analysis, the ECC group showed significantly better outcomes than the LT group across multiple domains. Early mortality rates were notably lower in the ECC group (1.2%) compared to the LT group (3.9%, p = 0.003), and late mortality similarly favored ECC with a rate of 3.2% versus 8.6% in LT (p = 0.003). At 20 years, Kaplan-Meier survival analysis revealed a marked survival advantage for ECC patients, with survival rates of 93% for ECC versus 84% for LT. Postoperative complications were also less frequent in the ECC cohort. ECC patients had significantly fewer instances of early postoperative complications (47% for ECC vs. 66% for LT, p = 0.025) and Fontan failure (12% for ECC vs. 19% for LT, p = 0.032); however, after multivariate regression to control for follow-up duration, the difference in Fontan failure between groups was no longer statistically significant, suggesting the time-dependent nature of this outcome. Kidney-related adverse events, including chronic kidney disease, were more common in LT patients, with an incidence of 3% in LT versus 0.6% in ECC (p = 0.004). While overall arrhythmia incidence was comparable post-matching, initial findings indicated that LT patients were more prone to tachyarrhythmias, possibly due to atrial sutures and scar tissue that may promote reentrant circuits. Long-term adverse events such as protein-losing enteropathy and hepatic complications did not show statistically significant differences between groups after propensity adjustment, though ECC patients had a slight advantage in terms of reduced late adverse events. Overall, ECC was associated with a more favorable risk profile, supporting its use as the preferred Fontan approach for better long-term outcomes. Conclusions: The findings suggest that the ECC approach offers better long-term outcomes compared to LT in Fontan patients, particularly in terms of survival and reduced adverse events. ECC may therefore be considered the preferred surgical technique for Fontan procedures. Ongoing long-term monitoring of Fontan patients remains essential to optimize clinical results across their lifespan.