Venous Compression in Fontan

NCT ID: NCT07220226

Last Updated: 2026-01-12

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2026-01-10
• Study Completion Date: 2027-11-01

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.

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

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SEQUENTIAL
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

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.

Group Type: EXPERIMENTAL

Lower extremity compression garments

Intervention Type: DEVICE

Acute and 2-week effects of compression garments

Without compression garments

Intervention Type: OTHER

Acute effects without compression garments

Healthy controls

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

Group Type: EXPERIMENTAL

Lower extremity compression garments

Intervention Type: DEVICE

Acute and 2-week effects of compression garments

Without compression garments

Intervention Type: OTHER

Acute effects without compression garments

Interventions

Lower extremity compression garments

Acute and 2-week effects of compression garments

Intervention Type: DEVICE

Without compression garments

Acute effects without compression garments

Intervention Type: OTHER

Eligibility Criteria

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.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Texas Southwestern Medical Center

OTHER

Sponsor Role: lead

Responsible Party

Keri Shafer

Associate Professor of Medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Keri Shafer, MD

Role: PRINCIPAL_INVESTIGATOR

University of Texas Southwestern Medical Center

Central Contacts

Keri Shafer, MD

Role: CONTACT

keri.shafer@utsouthwestern.edu

2146451165

Denis J Wakeham, PhD

Role: CONTACT

denis.wakeham@utsouthwestern.edu

2146451165

Other Identifiers

STU20250885

Identifier Type: -

Identifier Source: org_study_id