NCT07220226 · University of Texas Southwestern Medical Center
Venous Compression in Fontan
What this study is about
The aim of this study is to investigate whether venous compression garments increase exercise stroke volume in patients with Fontan circulation. To address this aim, we will test the following hypotheses: 1. Acute and chronic external venous compression will increase exercise stroke volume in patients with Fontan circulation. 2.
View original scientific description
The aim of this study is to investigate whether venous compression garments increase exercise stroke volume in patients with Fontan circulation. To address this aim, we will test the following hypotheses: 1. Acute and chronic external venous compression will increase exercise stroke volume in patients with Fontan circulation. 2. Patients with significant venous varicosities will have a greater response to venous compression. Participants will: * Undergo submaximal exercise testing in MRI to measure venous return and exercise stroke volume with and without the wearing of compression garments * Undergo submaximal exercise testing on a seated upright exercise ergometer with concurrent measurement of stroke volume with and without the wearing of compression garments * A subset of participants will repeat both testing visits after wearing compression garments for 2-weeks during waking hours. Participants will: * Undergo submaximal exercise testing in MRI to measure venous return and exercise stroke volume with and without the wearing of compression garments * Undergo submaximal exercise testing on a seated upright exercise ergometer with concurrent measurement of stroke volume with and without the wearing of compression garments * A subset of participants will repeat both testing visits after wearing compression garments for 2-weeks during waking hours.
Interventions
DEVICE
Lower extremity compression garments
Acute and 2-week effects of compression garments
OTHER
Without compression garments
Acute effects without compression garments
Primary outcome measures
Change in Stroke Volume with Exercise
Time frame: Rest (20 minutes), Exercise (10 minutes)
The change in single ventricular stroke volume from rest to moderate intensity exercise with compression garments during baseline testing
Change in Stroke Volume with Exercise
Time frame: Rest (20 minutes), Exercise (10 minutes)
The change in single ventricular stroke volume from rest to moderate intensity exercise without compression garments during baseline testing
Change in Stroke Volume with Exercise
Time frame: Rest (20 minutes), Exercise (10 minutes) at 2-weeks follow-up testing
The change in single ventricular stroke volume from rest to moderate intensity exercise following 2 weeks of wearing compression garments.
The Acute Effect of Compression Garments on Stroke Volume during Exercise
Time frame: Rest (20 minutes) and Exercise (10 minutes) repeated during baseline testing
The difference in the change in single ventricular stroke volume during moderate intensity exercise between baseline testing with (outcome #1) and without (outcome #2) garments
The Chronic Effect of Compression Garments on Stroke Volume during exercise
Time frame: Rest (20 minutes) and Exercise (10 minutes) completed during baseline and during follow-up testing
The difference in the change in single ventricular stroke volume during moderate intensity exercise between baseline testing without garments (outcome #2) and following 2 weeks of wearing compression garments (outcome #3) in patients with Fontan Circulation.
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 at UTSW aged 18-45 years old with a Fontan circulation.
Exclusion criteria
- NYHA Class 4
- Severe AV valve regurgitation
- Severe ventricular dysfunction
- Large ascites
- Significant varicosities
- Atrio-pulmonary (AP) Fontan
- Known Fontan thrombus
- Poorly controlled arrythmia
- Unplanned cardiac admission in the last 6 months
- Cyanosis (resting O2 saturation \<85%)
- Common femoral vein obstruction \>50% to be performed following completion of informed consent. Healthy Controls: Healthy control participants will be recruited on the basis of having no known chronic diseases and not currently taking any cardiovascular medications.
Where
- Dallas, Texas
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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 Jul 30, 2026 · Source of record for eligibility and locations