NCT07220226

Venous Compression in Fontan

Venous Function and the Effect of Venous Compression on Exercise Cardiovascular Function in Patients With Fontan Circulation.

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: University of Texas Southwestern Medical Center · Academic / Other
• Sex: All
• Age: 18 Years – 45 Years
• Healthy volunteers: Accepted

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.

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

Interventions

Type	Name	Description
DEVICE	Lower extremity compression garments	Acute and 2-week effects of compression garments
OTHER	Without compression garments	Acute effects without compression garments

Timeline

• Start date: 2026-01-10
• Primary completion: 2027-11-01
• Completion: 2027-11-01
• First posted: 2025-10-23
• Last updated: 2026-01-12

Regulatory

• FDA-regulated device study