12 to 18 Year Olds Who Have Had a Fontan Operation Needed for the Fontan Udenafil Exercise Longitudinal (FUEL) Research Study

Why are we doing this research?

Cincinnati Children’s is conducting a research study, sometimes known as a clinical trial or clinical study to learn if an investigational drug called udenafil can help children and young adults who have had a Fontan operation exercise better or maintain their ability to exercise longer over time.

Udenafil is considered investigational because the U.S. Food and Drug Administration (FDA) has not yet approved it. This means it can only be used in research studies.

What is the Pediatric Heart Network (PHN)?

This is a Pediatric Heart Network (PHN) research study. The PHN is a group of hospitals in the US and Canada that conducts research studies in children with heart disease and is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health.

Who can participate?

Preteens and teens 12 to 18 years old who have had a Fontan operation may be eligible for participation.


  • Cardiology - Heart

What will happen in the study?

If your child qualifies for this study, and you decide to participate, your family will be in this study for 9 months and have 4 in-person research study visits and 10 brief phone calls.

After the last in-person visit, participants may be contacted once a year for up to 10 years to see how their health is over time.

If your child can be in this study, he or she will take a pill by mouth 2 times a day for 6 months.

The following is a list of the tests and procedures that will happen during the study:

  • Medical records: Your child’s medical records will be reviewed.
  • Medical and family history: We will ask about medical and family history, current medicines and supplements.
  • Vital signs: We sill measure your child’s height, weight, heart rate and blood pressure.
  • Blood draws: A sample of your child’s blood will be taken from his or her vein (one time per visit) and will be used for various purposes.
  • Vascular function test (EndoPAT): This test will tell us about the function of your child’s blood vessels (while lying down, your child will wear a blood pressure cuff on his or her arm).
  • Echocardiogram: This is a painless test that uses sound waves to take pictures of the heart.
  • Exercise testing: This test looks at how your child’s heart functions while he or she is exercising on a stationary bike.
  • Resting lung function test: Your child will breathe in and out of tubes, and the amount of air and pressure of air flowing through the tubes will be measured.
  • ECG: This is a painless test that gives doctors information about the electrical signals that make your child’s heartbeat.
  • Questionnaires: Your child will be asked to answer some questions related to his or her health status and quality of life.

If your child is eligible to participate, he or she will be put in a treatment group “at random” (by chance – like flipping a coin) at the end of Visit 1 to take either udenafil or a placebo. A placebo is a pill that looks like udenafil but contains no active medicine. There is an equal chance of your child getting udenafil or placebo.

Neither you, your child, your child’s doctors nor the study team will know which treatment group your child is in; however, we can find out in an emergency. When the study is over, study staff will find out which treatment group your child was in, and we will tell you and your child’s doctors.

You and your child will be given a supply of the study medication and instructions on how to take it. Your child will also be provided with an iPod touch® that will be set up with reminders to let him or her know when to take each dose.

Someone from the study team will call your child weekly for the first 4 weeks to remind him or her to take the study drug and ask if he or she has experienced any side effects or adverse events. Then your child will receive calls monthly for the remainder of the study.

You, as a parent/guardian, will be given a consent form that thoroughly explains all of the details of the study. A member of the study staff will review the consent form with you and will be sure that all of your questions are answered.

What are the good things that can happen from this research?

Being in this study may not help your child right now. The results of test/procedures performed as part of the study may be shared with you, your child, and/or your child’s doctor upon request or upon clinically relevant findings.

If your child receives Udenafil, it is possible that your child’s ability to exercise will improve while they are taking it. However, because Udenafil is investigational and not approved by the FDA, your child’s doctor cannot prescribe it after he or she finishes the study. 

When we finish the study, we hope that we will be able to improve the care of children with similar problems in the future.  

What are the bad things that can happen from this research?

All possible risks will be discussed with you if you are interested in learning more about the study.

Will you/your child be paid to be in this research study?

Families will be paid for their time, effort and travel. Participants will also keep the iPod Touch® used during the study.


Contact Us.Kathleen Ash
Cincinnati Children’s Hospital Medical Center
3333 Burnet Avenue
Cincinnati, OH  45229-3039

Study Doctor

Contact Us.Bryan H. Goldstein, MD
Cincinnati Children’s Hospital Medical Center
Heart Institute