Impact of Therapy Using Colesevelam Treatment Reducing Bile Acids in Patients With Fontan Circulation.

The investigators propose a prospective, double-blind, placebo cross-over, pilot study evaluating colesevelam (intestinal BA scavenger) therapy and placebo in 25 stable adult FC participants. These participants will be recruited from the cardiology clinics at the St. Boniface Hospital, specifically the Manitoba Adult Congenital Heart (MACH) Clinic. Participants will be randomized to be treated with either colesevelam (625 mg tablets - 3 tables twice per day) or placebo (3 tablets twice per day) for 6 weeks, interspersed by 8 week of washout time. Local research and ethics board approval will be obtained. Informed consent will be obtained from all participants. A further 25 age- and sex- matched healthy control participants will be recruited from advertising at St. Boniface Hospital and University of Manitoba. These healthy control participants will be comparators to the randomized Fontan participants at baseline. Recruitment of this group will be completed after all Fontan participants have been screened, consented, and randomized to ensure accuracy of age and sex matching. Age and sex matched participants will be +/- 3 years and not pregnant or nursing at time of study visit.