Structural and functional uncoupling of liver performance in the Fontan circulation

BackgroundThe liver is known to be structurally abnormal in long-standing Fontan circulation. The degree of liver dysfunction associated with such abnormalities is however largely unknown. We assessed structural changes (serum fibrosis markers) and function (indocyanine green clearance (ICG)) in Fontan patients.Methods21 stable Fontan patients were prospectively assessed and compared with 8 histologically proven compensated viral cirrhotic patients. All subjects had standard liver profile, “Enhanced Liver Fibrosis” (ELF) score (including hyaluronic acid, aminoterminal type III procollagen peptide P3NP and tissue inhibitor of metalloproteinase TIMP-1 levels), and ICG using the LiMON Device. Plasma disappearance rate (PDR) and 15-minute retention (R15) were recorded after ICG infusion.ResultsIndocyanine clearance and retention (PDR and R15) were similar between Fontan and compensated cirrhotic patients (17 ± 5 vs 18 ± 6 (p = 0.75) and 11 ± 10 vs 10 ± 10 (p = 0.75)), as was degree of fibrosis (7.97 ± 1.16 vs 9.0 ± 1.43, p = NS). There was a positive correlation between PDR and ELF (R = 0.77, p = 0.028) as well as R15 and ELF (R = 0.905, p = 0.002) in the viral cirrhotics but not in the Fontan group. (R = − 0.243, p = 0.302; and R = 0.226, p = 0.338). PDR (17 ± 5) and R15 (11 ± 10) were not significantly different in Fontan as compared with the established cirrhotics.ConclusionsFontan patients have similar global hepatic function and fibrosis as compared with viral cirrhotic patients. However in Fontan patients, fibrosis was not closely correlated with global liver function, whereas viral cirrhotic patients exhibited a close correlation between function and fibrosis.