Recruiting

Venous Compression

Sponsor:

University of Texas Southwestern Medical Center

Code:

NCT07220226

Conditions

Single-ventricle

Fontan Circulation

Eligibility Criteria

Sex: All

Age: 18 - 45

Healthy Volunteers: Accepted

Interventions

Lower extremity compression garments

Without compression garments

Study Details

Brief 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. 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.

Conditions

Single-ventricle

Fontan Circulation

Study ID

NCT07220226

Start date

May 10, 2026

Status verified date

Mar, 2026

Completion date

Nov 1, 2027

Anticipated

Primary completion date

Nov 1, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 45

Healthy Volunteers: Accepted

Patients with a Fontan circulation -

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%)
  • 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.

Study Design

Enrollment

20 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Other

Interventions and Outcome Measures

Arms

experimental: Fontan circulation Arm

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.

experimental: Healthy controls

Healthy group participants will undergo Rest +Submax exercise with and without wearing venous compression garments.

Interventions

Lower extremity compression garments

Acute and 2-week effects of compression garments

Without compression garments

Acute effects without compression garments

Primary outcome measure

  • Change in Stroke Volume with Exercise [ Time Frame: Rest (20 minutes), Exercise (10 minutes) ]
  • Change in Stroke Volume with Exercise [ Time Frame: Rest (20 minutes), Exercise (10 minutes) ]
  • Change in Stroke Volume with Exercise [ Time Frame: Rest (20 minutes), Exercise (10 minutes) at 2-weeks follow-up testing ]
  • 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 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 ]

Central Contacts and Locations

Central contacts

Keri Shafer, MD

2146451165keri.shafer@utsouthwestern.edu

Denis J Wakeham, PhD

2146451165denis.wakeham@utsouthwestern.edu

Locations

UT Southwestern Medical Center

Recruiting

Dallas, Texas, United States, 75390

Contacts

Keval Patel, M.D.

214-345-4670keval.patel@utsouthwestern.edu

Principal Investigator:

Keri Shafer, M.D.

More Information

Sponsor

University of Texas Southwestern Medical Center

Last update posted

Jul 30, 2026

Last verified

Mar, 2026

Keywords

  • Venous Compression
  • Exercise Testing
  • Cardiac Reserve
  • Fontan Circulation
  • Magnetic Resonance Imaging
  • vascular function

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Texas Southwestern Medical Center on 2026-07-30.