NCT05206955 · Mayo Clinic
Study of Tadalafil vs. Placebo for Improving Hemodynamics and End-Organ Dysfunction in Fontan Physiology
What this study is about
The purpose of this study is to find out more about the effectiveness of Tadalafil in improving hemodynamic capabilities, endothelial function, and end-organ function in patients who have previously undergone a Fontan Palliation.
View original scientific description
The purpose of this study is to find out more about the effectiveness of Tadalafil in improving hemodynamic capabilities, endothelial function, and end-organ function in patients who have previously undergone a Fontan Palliation.
Interventions
DRUG
Tadalafil
10 mg once daily orally week 1, 20 mg once daily orally during week 2, and 40 mg once daily orally during weeks 3 through 52
DRUG
Placebo
Looks exactly like the study drug, but it contains no active ingredient
Primary outcome measures
Microvascular endothelial function
Time frame: 52 weeks
Measured by the reactive hyperemic index using peripheral artery tonometry (EndoPAT)
Pulmonary vascular reserve
Time frame: 52 weeks
The slope of mean pulmonary artery pressure / cardiac output (mPAP/CO)
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patients ≥ 18 years old.
- Have previously undergone a Fontan Palliation.
- Able to exercise using a supine bike.
- Ability and willingness to provide written consent.
- Undergoing a clinically indicated Cardiac Catheterization
Exclusion criteria
- Patients \< 18 years old.
- Current intravenous inotropic drugs.
- Current use of alpha-blockers, pulmonary vasodilators, or nitrates.
- Unable to exercise.
- Pregnancy or lactating.
- Unable or unwilling to consent.
Where
- Rochester, Minnesota
Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Aug 13, 2026 · Source of record for eligibility and locations