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 more about the safety of an investigational drug called Udenafil in teens and young adults who have had a Fontan procedure. We also want to evaluate the effectiveness of the drug on exercise ability, heart function and quality of life.

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?

Pre-teens, teens and young adults, 12 to 18 years old, who have had a Fontan operation with may be able to participate.


  • Cardiology - Heart

What will happen in the study?

If you (as a participant who is 18 years) or your teen qualify for this study, and you decide to participate, you will have 4 in-person visits and 14 phone calls over a period of about 1 year and 3 months.

The following is a list of the tests and procedures that will happen during 1 or more study visits:

  • Review of medical records
  • Review of medical and medication history: study staff will ask about medical history, current and past medicines and supplements
  • Review of demographic information: study staff will ask about family and demographic information
  • Vital sign measurements: height, weight, resting heart rate and blood pressure
  • Collection of blood samples: used for various lab tests
  • Collection of urine samples: for pregnancy test (for female participants only)
  • Vascular function test (EndoPAT): a test that looks at the function of the blood vessels using a cuff on the arm to measure resting blood pressure
  • Echocardiogram: a painless test that uses sound waves to take pictures of the heart
  • Exercise testing: a test that looks at how the heart functions while exercising on a stationary bike
  • Resting lung function test: a test that looks at how the lungs are working while resting
  • Questionnaires: questions related to health status and quality of life

You/your teen will have a first visit, or Baseline visit, to make sure you are eligible to participate in the FUEL OLE extension study.

If you/your teen are eligible to participate, you will receive 1 dose of Udenafil during this same Baseline visit. You/your teen will stay at Cincinnati Children’s for observation, to make sure there are no adverse events, for about 4 hours after taking the Udenafil. While under observation, study staff will take resting heart rate and blood pressure measurements, blood samples and you/your teen will perform a 6-minute walk.

Once the observation period is over, you/your teen will receive an initial supply of Udenafil to take home. You/your teen will take the study drug 2 times per day for 52 weeks (1 year).

Research coordinators will call you/your teen the day after the first visit to make sure the Udenafil is being tolerated.

About 2 weeks, 13 weeks and 52 weeks after first receiving udenafil, you/your teen will return for in-person visits. You/your teen will bring back the medication bottle at the each of these visits.

Finally, research coordinators will call you/your teen 11 times in between the study visits as well as 30 and 90 days after the final in-person visit to record any adverse events.

You, as a parent/guardian or participant, 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 or may not help you/your teen right now. The results of tests/procedures performed as part of the study may be shared with you, your teen, and/or your doctor upon request or upon clinically relevant findings.

After receiving Udenafil, it is possible that you/your teen’s ability to exercise will improve while taking the drug. However, because Udenafil is investigational and not approved by the FDA, you/ your teen’s doctor cannot prescribe it after the study is completed.

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?

Participants will be paid for their time, effort and travel.


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