Fontan Udenafil Exercise Longitudinal Study (FUEL)

Condition: Fontan physiology


Key Inclusion Criteria

  • Males and females with Fontan physiology who are 12 to 18 years old at enrollment
  • Participant fluent in English, Spanish, or Korean
  • Participant consent or parental/guardian consent and participant assent

Key Exclusion Criteria

  • Height less than 132 cm (approximately 52 inches)
  • Weight less than 40 kg (88.18 pounds)
  • Hospitalization for acute decompensated heart failure within the last 12 months

Full Study Name

Fontan Udenafil Exercise Longitudinal Assessment Trial (IRB no. 44590)


This study focuses on children who have had a Fontan operation (a procedure used in patients with only one functional ventricle). This study is designed to evaluate the effect of six months of treatment with an investigational drug called udenafil on exercise capacity in adolescents with Fontan physiology. Researchers will compare udenafil to placebo (inactive substance) to better understand the effect udenafil has on young patients who have had a Fontan surgery. Participants will receive either udenafil (87.5 mg twice daily) or placebo.


Phase III

Principal Investigator

Ruchira Garg, MD