Abstract 17110: Risk Factors for Hepatic Fibrosis in Children and Adolescents After Fontan Operation

Introduction: Congestive hepatopathy is increasingly recognized as a complication of Fontan physiology. Prospective data regarding the incidence of hepatopathy and risk factors for its development are lacking. Methods: Liver biopsies were obtained as part of a routine program of comprehensive end-organ evaluation offered to all patients >10 years after Fontan operation (FO) through the Single Ventricle Survivorship Program. Evaluation included cardiac catheterization and contemporaneous percutaneous liver biopsy. Quantitative determination of hepatic fibrosis was performed using Sirius red staining for collagen with automated calculation of percent positive staining per slide. Patient specific characteristics, echocardiographic findings, and hemodynamic measures were assessed and evaluated as potential risk factors for collagen deposition using Pearson correlation. Differences in collagen deposition (%CD) between subgroups were assessed using the student t-test. Results: The cohort consisted of 67 patients (36 male) at mean age of 17.3 ±4.5 years and mean time from Fontan of 14.9 ±4.5 years. Right ventricular morphology was present in 37 subjects; 30 with hypoplastic left heart syndrome. Mean %CD by Sirius red staining was 23.8 ±9.5% (range 8.7-49.4%) as compared to 2.6 ±0.3% in controls. There was significant correlation between time from Fontan and degree of Sirius red staining (r=0.33, p=0.006). Serum liver enzymes and platelet count did not correlate with %CD. The median inferior vena cava (IVC) pressure was 13 mmHg (range 6-24 mmHg) and did not correlate with %CD. There was no difference in %CD between those with a measured IVC pressure ≥13 mmHg versus those with a pressure Conclusion: In this cohort of predominantly asymptomatic children and adolescents electively evaluated after FO, all exhibited evidence for hepatic fibrosis as measured by collagen deposition in the liver. Time from FO was the only factor in this cohort that was significantly associated with collagen. These findings demonstrate that liver fibrosis is an inherent feature of Fontan physiology and that the degree of fibrosis increases over time.