The aims of this study are four-fold: (1) To determine if cholate clearance is related to underlying cardiovascular hemodynamics, specifically low CO, elevated CVP, desaturation as seen in the Fontan. (2) To characterize Fontan patients with elevated systemic HFR/portal HFR ratio. (3) To know whether cholate clearance is a reliable measure of hepatic perfusion. (4) To determine whether cholate clearance is predictive of clinical outcomes: heart failure, clinically significant ascites, new-onset protein losing enteropathy, hepatocellular carcinoma, transplant, or death. The primary outcome of interest is cholate clearance as assessed by the dual cholate clearance test: systemic HFR (ml/min/kg), clearance of intravenously administered 13C-Cholate (Dose (mg) area under the curve [AUC] (mg mL1 min kg)); portal HFR (ml/min/kg), clearance of orally administered d4-Cholate (Dose (mg) AUC (mg mL1 min kg)); and the ratio of systemic to portal flow (systemic HFR/portal HFR ratio). Decrease in portal flow and/or increase in systemic flow results in a higher ratio.
Systemic HFR/portal HFR ratio will be examined as a measure of liver disease and values greater than 30% will be considered abnormal. A secondary outcome is a composite outcome of new-onset heart failure (defined as hospitalization for intravenous diuresis), progressive heart failure (defined as referral for heart or combined heart-liver transplant), clinically significant ascites (defined as requiring large volume paracentesis), new-onset protein-losing enteropathy, hepatocellular carcinoma, heart transplant or a combined heart and liver transplant, or death.
