Single-ventricleNCT07220226
Venous Compression in Fontan
A study testing Lower extremity compression garments and Without compression garments in people with Single-ventricle and Fontan Circulation, run by University of Texas Southwestern Medical Center at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Single-ventricle, Fontan Circulation
- What is being tested?
- Lower extremity compression garments and Without compression garments
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 10 May 2026to 1 Nov 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Patients at UTSW aged 18-45 years old with a Fontan circulation.
Who cannot join
- NYHA Class 4
- Severe AV valve regurgitation
- Severe ventricular dysfunction
- Large ascites
- Significant varicosities
- Atrio-pulmonary (AP) Fontan
Show all 14Show fewer
- Known Fontan thrombus
- Poorly controlled arrythmia
- Unplanned cardiac admission in the last 6 months
- Cyanosis (resting O2 saturation <85%)
- Pregnant
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
UT Southwestern Medical Center
Dallas, Texas, 75390
Keval Patel, M.D., 214-345-4670, keval.patel@utsouthwestern.edu
Keri Shafer, M.D.
About this study
Official title: Venous Function and the Effect of Venous Compression on Exercise Cardiovascular Function in Patients With Fontan Circulation.
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:
- Acute and chronic external venous compression will increase exercise stroke volume in patients with Fontan circulation.
- Patients with significant venous varicosities will have a greater response to venous compression.
Read more
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.
Read the detailed description
Study Day 1 - Consent, Screening and Garment Measurements:
Following assessment of participant eligibility, all participants will undergo leg venous ultrasound assessment and abdominal-foot measurements for the custom making of compression garments.
Study Day 2 - MRI:
Study participants will undergo comprehensive cardiovascular MRI using a 3T MRI scanner with and without compression garments and exercise.
Study Day 3 - Cardiovascular \& Exercise Testing Day:
All participants will undergo comprehensive cardiovascular structure and function assessments at rest and during exercise with and without the wearing of compression garments. Baseline testing will include dual x-ray absorptiometry (DEXA), pulmonary function testing, comprensive vascular assessments and echocardiography. During exercise at two submaximal workloads, the study team will measure blood pressure, oxygen uptake and cardiac output.
- Conditions
- Single-ventricle, Fontan Circulation
- Being tested
- Lower extremity compression garments, Without compression garments
- Keywords
- Venous Compression, Exercise Testing, Cardiac Reserve, Fontan Circulation, Magnetic Resonance Imaging, vascular function
- Medical subject headings
- Univentricular Heart
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Lower extremity compression garmentsDevice
Acute and 2-week effects of compression garments
Without compression garmentsOther
Acute effects without compression garments
| Study group | Role | What they receive |
|---|---|---|
| Fontan circulation Arm | Experimental | Fontan circulation participants will undergo Rest +Submax exercise with and without wearing venous compression garments.
A subset of patients with Fontan circulation will undergo repeat testing 2-weeks later. Receives: Device: Lower extremity compression garments; Other: Without compression garments |
| Healthy controls | Experimental | Healthy group participants will undergo Rest +Submax exercise with and without wearing venous compression garments. Receives: Device: Lower extremity compression garments; Other: Without compression garments |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Stroke Volume with Exercise
The change in single ventricular stroke volume from rest to moderate intensity exercise with compression garments during baseline testing
Measured: Rest (20 minutes), Exercise (10 minutes)
Change in Stroke Volume with Exercise
The change in single ventricular stroke volume from rest to moderate intensity exercise without compression garments during baseline testing
Measured: Rest (20 minutes), Exercise (10 minutes)
Change in Stroke Volume with Exercise
The change in single ventricular stroke volume from rest to moderate intensity exercise following 2 weeks of wearing compression garments.
Measured: Rest (20 minutes), Exercise (10 minutes) at 2-weeks follow-up testing
The Acute Effect of Compression Garments on Stroke Volume during Exercise
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
Measured: Rest (20 minutes) and Exercise (10 minutes) repeated during baseline testing
The Chronic Effect of Compression Garments on Stroke Volume during exercise
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.
Measured: Rest (20 minutes) and Exercise (10 minutes) completed during baseline and during follow-up testing
Secondary outcomes (5)
Change in Venous Return with Exercise
The change in inferior vena cava flow from rest to moderate intensity exercise with compression garments using MRI during baseline testing
Measured: Rest (10 minutes) and Exercise (5 minutes)
Change in Venous Return with Exercise
The change in inferior vena cava flow from rest to moderate intensity exercise without compression garments using MRI during baseline testing
Measured: Rest (10 minutes) and Exercise (5 minutes)
Change in Venous Return with Exercise
The change in inferior vena cava flow from rest to moderate intensity exercise following 2 weeks of wearing compression garments using MRI
Measured: Rest (10 minutes) and Exercise (5 minutes)
The Acute Effect of Compression Garments on Changes in Venous Return with Exercise
The difference in the change in inferior vena cava flow during moderate intensity exercise between baseline testing with (outcome #6) and without (outcome #7) garments
Measured: Rest (10 minutes) and Exercise (5 minutes) repeated during baseline testing
The Chronic Effect of Compression Garments on Changes in Venous Return with Exercise
The difference in the change in inferior vena cava flow during moderate intensity exercise between baseline testing without garments (outcome #7) and following 2 weeks of wearing compression garments (outcome #8) in patients with Fontan Circulation.
Measured: Rest (10 minutes) and Exercise (5 minutes) completed during baseline and during follow-up testing
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Oct 2025
- Study start10 May 2026
- Primary completion1 Nov 2027 (estimated)
- Study completion1 Nov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Single-ventricleStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Texas Southwestern Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Keri Shafer, University of Texas Southwestern Medical Center
- Investigators
- Keri Shafer, MD, Principal investigator, University of Texas Southwestern Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07220226
- Sponsor's protocol ID
- STU20250885
- Status last verified
- Mar 2026
- First submitted
- 25 Sep 2025
- Last updated
- 30 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 30 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Venous Function and the Effect of Venous Compression on Exercise Cardiovascular Function in Patients With Fontan Circulation.
- ClinicalTrials.gov ID
- NCT07220226
- Acronym / sponsor ID
- STU20250885
- Conditions
- Single-ventricle, Fontan Circulation
- Keywords
- Venous Compression, Exercise Testing, Cardiac Reserve, Fontan Circulation, Magnetic Resonance Imaging, vascular function
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University of Texas Southwestern Medical CenterUniversity, hospital or other
- Study start
- 10 May 2026 (actual)
- Primary completion
- 1 Nov 2027 (estimated)
- Study completion
- 1 Nov 2027 (estimated)
- First posted
- 23 Oct 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- Acute and chronic external venous compression will increase exercise stroke volume in patients with Fontan circulation.
- 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.
Detailed description
Study Day 1 - Consent, Screening and Garment Measurements:
Following assessment of participant eligibility, all participants will undergo leg venous ultrasound assessment and abdominal-foot measurements for the custom making of compression garments.
Study Day 2 - MRI:
Study participants will undergo comprehensive cardiovascular MRI using a 3T MRI scanner with and without compression garments and exercise.
Study Day 3 - Cardiovascular \& Exercise Testing Day:
All participants will undergo comprehensive cardiovascular structure and function assessments at rest and during exercise with and without the wearing of compression garments. Baseline testing will include dual x-ray absorptiometry (DEXA), pulmonary function testing, comprensive vascular assessments and echocardiography. During exercise at two submaximal workloads, the study team will measure blood pressure, oxygen uptake and cardiac output.
Study design
- Primary purpose
- Other
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Fontan circulation Arm | Experimental | Device: Lower extremity compression garments, Other: Without compression garmentsFontan circulation participants will undergo Rest +Submax exercise with and without wearing venous compression garments. A subset of patients with Fontan circulation will undergo repeat testing 2-weeks later. |
| Healthy controls | Experimental | Device: Lower extremity compression garments, Other: Without compression garmentsHealthy group participants will undergo Rest +Submax exercise with and without wearing venous compression garments. |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Patients at UTSW aged 18-45 years old with a Fontan circulation.
Key exclusion criteria (14 listed)
- NYHA Class 4
- Severe AV valve regurgitation
- Severe ventricular dysfunction
- Large ascites
- Significant varicosities
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Lower extremity compression garmentsAcute and 2-week effects of compression garments | Device | Fontan circulation Arm, Healthy controls |
| Without compression garmentsAcute effects without compression garments | Other | Fontan circulation Arm, Healthy controls |
Primary outcome
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.
5 secondary outcomes
Change in Venous Return with Exercise
Time frame: Rest (10 minutes) and Exercise (5 minutes)
Change in Venous Return with Exercise
Time frame: Rest (10 minutes) and Exercise (5 minutes)
Change in Venous Return with Exercise
Time frame: Rest (10 minutes) and Exercise (5 minutes)
The Acute Effect of Compression Garments on Changes in Venous Return with Exercise
Time frame: Rest (10 minutes) and Exercise (5 minutes) repeated during baseline testing
The Chronic Effect of Compression Garments on Changes in Venous Return with Exercise
Time frame: Rest (10 minutes) and Exercise (5 minutes) completed during baseline and during follow-up testing
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jul 2026.
- Individual participant dataSharing planned: No
Related trials for Single-ventricle
RecruitingPhase 1
A Study of SGT-501 Gene Therapy in Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
Catecholaminergic Polymorphic Ventricular Tachycardia
Recruiting
Trial of the F2 Filter and Delivery System for Embolic Protection During TAVR
Aortic Stenosis Treated With TAVI, Aortic Diseases
RecruitingPhase 1
Phase I Study of Oral ONC206 in Recurrent and Rare Primary Central Nervous System Neoplasms
Central Nervous System Neoplasms, Glioblastoma
RecruitingObservational study
Long-term Safety Study Following to JRM-001 Treatment in Pediatric Patients With Congenital Heart Disease
Single Ventricle, Hypoplastic Left Heart Syndrome (HLHS)
Recruiting
SPIKE FLOW Endocardial Lead Safety and Performance Study
Acute Myocardial Infarction (AMI), Asystole
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Keri Shafer, MD principal investigator
University of Texas Southwestern Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Lower extremity compression garments and Without compression garments in people with Single-ventricle and Fontan Circulation, run by University of Texas Southwestern Medical Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Keri Shafer, MD (2146451165, keri.shafer@utsouthwestern.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Stroke Volume with Exercise (time frame: Rest (20 minutes), Exercise (10 minutes)). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jul 2026.