Non-Invasive Markers of Liver Fibrosis in Patients After Fontan Surgery: A Case Series

Background Fontan circulation predisposes patients to Fontan-Associated Liver Disease (FALD), characterized by chronic congestion and progressive hepatic fibrosis. Although liver biopsy is the gold standard for fibrosis assessment, its use is limited owing to the risk of complications in these patients. In this context, liver elastography and non-invasive serum markers of fibrosis, such as APRI and FIB-4, have been proposed as alternatives for liver monitoring; however, their applicability and correlation with the progression of FALD in pediatric patients remain uncertain. Methods This was an observational case series cohort with both retrospective and prospective components, including patients with univentricular congenital heart disease who underwent the Fontan procedure and had liver elastography performed during follow-up. Liver stiffness was assessed using the 2D-SWE method. Clinical and laboratory data (AST, ALT, and platelets count) were collected to calculate APRI and FIB-4. Spearman correlation and partial correlation analyses were performed to identify factors associated with liver elastography. In the subgroup with longitudinal assessments, paired tests were applied. Results A total of 32 patients (62.5% male) were included with a mean age of 3.75 ± 1.77 years at the time of Fontan surgery and 13.83 ± 8.18 years at the time of elastography evaluation. The mean liver stiffness was 12.05 ± 2.49 kPa. No significant correlation was found between liver elastography and APRI or FIB-4, nor was there any association with sex, age at surgery, or age at elastography evaluation. In the longitudinal subgroup (N = 22), no significant variation was observed between LE1 and LE2, nor were there relevant changes in APRI and FIB-4 over time. Conclusions In pediatric post-Fontan patients, liver elastography did not correlate with APRI or FIB-4, nor with the clinical variables analyzed, in both cross-sectional and longitudinal assessments. The findings suggest limitations of serum markers and reinforce the need for specific and validated strategies for liver monitoring in this population.