Impact of Fenestration on Survival and Morbidity Following Fontan Surgery: A Time-to-Event Meta-Analysis of Reconstructed Kaplan–Meier Data

IntroductionThe Fontan procedure revolutionized single-ventricle palliation by enabling passive pulmonary blood flow. Fenestration, an atrial-level shunt, reduces early postoperative complications by decompressing the circuit but causes systemic desaturation. Despite early benefits, fenestration's long-term impact on survival and morbidity remains uncertain.MethodsReconstructed meta-analysis data from Kaplan-Meier curves of studies published up to December 25, 2024, following PRISMA guidelines was performed. Eligibility included Fontan patients with documented fenestration status and survival outcomes. Hazard ratios were estimated using Cox regression analysis with random effects, and proportional hazards violations were addressed with flexible parametric models.ResultsEight studies met our eligibility criteria and included 2,827 unmatched patients and 804 matched Fontan patients included in the Kaplan-Meier curves (1308 + 402 with fenestration and 1519 + 402 without fenestration). Fenestration was associated with significantly lower overall survival (HR 1.58; p = 0.006) and had increased thromboembolism risk. Subgroup analysis showed lower survival among patients without documented active fenestration closure. Regression findings imply that the effectiveness of fenestration is influenced by baseline hemodynamic severity.ConclusionsFenestration in the Fontan procedure is associated with relatively lower long-term survival and increased thromboembolic risk. The benefits of fenestration may be greatest in patients with severe hemodynamic compromise, supporting a tailored rather than uniform approach to its application.