The Effects of Sildenafil on Exercise Function and Capacity in Patients With Fontan Circulation

Study Overview
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Brief Summary
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The study will test the hypothesis that a single dose of sildenafil can increase the exercise capacity of pediatric patients with a Fontan Circulation.

Official Title
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The Effects of Sildenafil on Exercise Function and Capacity in Patients With Fontan Circulation

Conditions
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Fontan Circulation

Intervention / Treatment
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* Drug: Sildenafil
* Drug: Placebo
* Drug: Sildenafil 2
* Drug: Placebo 2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 6-17 years Male or female Possess Fontan Circulation Exclusion Criteria: Severe heart failure (New York Heart Ass. functional class IV) Evidence of Fontan pathway obstruction History of exercise-induced severe arrhythmias Pregnancy (known or suspected) Orthopedic limitations that prevent ambulation on a treadmill Use of nitroglycerin Herbal medications

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 17 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Sildenafil crossover to placebo<br>Sildenafil dosage (0.5mg/kg (max 20mg)) administered at the time of enrollment followed by a battery of exercise tests. After a washout period, the process will be repeated with treatment 2, placebo drug administered before the exercises. | Drug: Sildenafil<br>* oral suspension, 0.5mg/kg, taken once prior to exercise stress test. Enrolled patients will be randomized to receive Sildenafil first and then crossed over to receive the opposite intervention, placebo.<br>* Other names: Viagra;Drug: Placebo 2<br>* Patient will receive a look-alike placebo. Enrolled patients will receive Placebo, the crossed over intervention from their initial intervention (Sildenafil).<br>* Other names: Ora-sweet and Ora-plus (1:1 ratio).;|
| Placebo Comparator: Placebo crossover to sidenafil<br>Patient will receive a look-alike placebo administered at the time of enrollment followed by a battery of exercise tests. After a washout period, the process will be repeated with treatment 2 Sildenafil dosage will be 0.5mg/kg (max 20mg) administered before the exercises. | Drug: Placebo<br>* Patient will receive a look-alike placebo. Enrolled patients will be randomized to receive Placebo first and then crossed over to receive the opposite intervention, Sildenafil.<br>* Other names: Ora-sweet and Ora-plus (1:1 ratio).;Drug: Sildenafil 2<br>* oral suspension, 0.5mg/kg, taken once prior to exercise stress test. Enrolled patients will receive Sildenafil, the crossed over intervention from their initial intervention (Placebo).<br>* Other names: Viagra;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Change in Exercise Capacity Measured Via Maximum Oxygen Consumed During Exercise (VO2) | A change in exercise capacity measured via maximum oxygen consumed during exercise (VO2). The measurement will be obtained from the Exercise Stress Test | baseline to 1 hour | 
| The Change in Exercise Capacity Measured Via Exercise Time | A change in exercise capacity measured via exercise time (in minutes). The measurement will be obtained from the Exercise Stress Test | baseline to 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Change in Exercise Capacity Measured Via Maximum Heart Rate | A change in exercise capacity measured via maximum heart rate (in beats per minute). The measurement will be obtained from the Exercise Stress Test | Baseline to 1 Hour | 
| The Change in Exercise Capacity Measured Via Minimum Oxygen Saturation Levels. | A change in exercise capacity measured via minimum oxygen saturation (%). The measurement will be obtained from the Exercise Stress Test | Baseline to 1 Hour | 
| The Change in Exercise Capacity Measured Via Metabolic Equivalents of Task (METs). | A change in exercise capacity measured via metabolic equivalents of task (METs). The measurement will be obtained from the Exercise Stress Test. One MET is defined as 3.5 mL 02 uptake/kg per minute | Baseline to 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fontan, sildenafil, exercise capacity, Patients with Fontan Circulation