Transjugular Liver Biopsy in Children Undergoing Fontan Surgery: Safety and Comparison of Fibrosis Grade with Non-invasive Tests.

This study aimed to assess the safety and diagnostic utility of transjugular liver biopsy (TJLB) in children with Fontan-associated liver disease (FALD) and to compare biopsy‑proven liver fibrosis with findings from noninvasive tests. A retrospective, single-center study of children under 18 years, Fontan surgery, underwent TJLB from 2019 to 2025. Data collected included demographics, cardiac anatomy, laboratory tests, ultrasound, Doppler, elastography, hemodynamic measurements, and histological fibrosis staging. A total of 28 biopsies were obtained from 26 patients, with a mean biopsy age of 16 ± 1.5 years and mean time since Fontan of 10.6 ± 1.5 years. Endoscopy revealed esophageal varices in 61% (36% grade II, 25% grade I). Laboratory abnormalities included thrombocytopenia in 39% and elevated ALT in 35% (30.9 ± 17.4 IU/L). Ultrasound showed homogeneous hepatomegaly in 57%, heterogenity in 25%, nodules in 7%, and splenomegaly in 57%. Elastography suggested advanced fibrosis in most patients (63% F4; mean 13.25 ± 4 kPa). However, biopsy demonstrated only 21.4% grade 4 fibrosis, with 64% showing grade 2–3. Sinusoidal dilatation (86%) and perisinusoidal fibrosis (86%) were the predominant findings. Complications were minimal: one mild hepatic hematoma and two minor pneumothoraxes. No significant correlation was found between histological fibrosis and elastography, ultrasound, or laboratory indices. TJLB is a safe, effective diagnostic tool in pediatric FALD and can be performed alongside hemodynamic evaluation by catheterization and endoscopy. In our series, elastography tended to overestimate fibrosis severity compared with biopsy.