Abstract 14429: Clinical and Laboratory Correlates of Impaired Cholate Clearance in the Adult Fontan

Abstract

Introduction: The dual cholate test is a noninvasive, flow-dependent assay measuring hepatic clearance of bile acid, cholate. A measure of liver function, cholate clearance has been shown to be decreased in the Fontan. We aim to explore the association between clinical features, cardiac/liver testing, laboratory tests and cholate clearance in a cohort of Fontan patients. Methods: Single center, prospective study of Fontan patients ≥ 18 years. Hepatic clearance of orally administered d4-cholate and intravenously administered 13C-cholate were measured in peripheral venous samples and calculated as portal hepatic filtration rate (HFR), systemic HFR, shunt fraction (systemic HFR/portal HFR), and disease severity index (DSI). Subjects were grouped according to shunt fraction (abnormal >30%) and/or DSI (abnormal >18.3). Kruskall-Wallis and Fisher exact tests were performed to analyze between-group differences. Results: Twenty-four Fontan patients were enrolled (50% female, median age 30.3 [interquartile range IQR 25.0 - 36.5] years, median cardiac index 2.91 [IQR 2.50 - 3.24] ml/mg/m2). Median total bilirubin was 0.95 [IQR 0.6 - 1.2] mg/dL, AST 29.5 [IQR 21.0 - 38.3] U/L, ALT 26.5 [IQR 20.8 - 36.3] U/L, alkaline phosphatase 75.5 [IQR 68.3 - 94.8] U/L, albumin 4.6 [IQR 4.3 - 4.7] g/dL, alpha fetoprotein 2.0 [1.9 - 3.0] ng/mL, platelets 177 [IQR 142.8 - 189.3] 10 3 /μL. There were no subjects with abnormal shunt fraction and normal DSI (Table). Conclusions: Oxygen saturation, alkaline phosphatase, and alpha fetoprotein correlate with abnormal cholate clearance whereas cirrhosis on imaging and Fontan pressures trended towards an association. Larger studies are warranted to explore these associations with cholate clearance to elucidate the nature of Fontan associated liver disease.