Venous Compression in Fontan

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.

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.