Lymphatic Morphology of Fontan Patients

Study Overview
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Brief Summary
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The Fontan procedure has revolutionized the treatment of patients born with a congenital univentricular heart defect. However, over time, it is associated with severe lymphatic complications such as plastic bronchitis, protein-losing enteropathy (PLE) and peripheral edema. The hypothesis is that patients with a univentricular circulation have a changed morphology which may be associated with both the degree of lymphatic complications and their physical capacity. The morphology will be described using T2-weighted non-contrast MRI.

Detailed Description
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The Fontan procedure has revolutionized the treatment of patients born with a congenital univentricular heart defect. However, over time, it is associated with severe lymphatic complications such as plastic bronchitis, protein-losing enteropathy (PLE) and peripheral edema. It has been proposed that these complications arise due to a elevated central venous pressure of the changed circulation. The hypothesis of the study is that patients with a univentricular circulation have a changed morphology which may be associated with both the degree of lymphatic complications and their physical capacity. The morphology will be described using T2-weighted non-contrast MRI. The main lymphatic vessel, the thoracic duct, will be rendered and measured using 3D software, and the lymphatic changes characterized by Dr. Yoav Dori (CHOP, Pennsylvania, USA), using a newly published grading system. The above will be correlated with the amount of complications experienced by the patients, and their physical capacity measured by both IPAQ questionaire and CPX test. The study population consists of patients with a Fontan circulation operated at InCor Heart Institute, São Paulo, Brasil and Hospital das Clínicas, Ribeirão Preto, Brasil. Exclusion criteria were mental illness, genetic syndromes and age <18 years. The patient group will be compared with age, gender and weight matched healthy controls.

Official Title
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Lymphatic Morphology and Classification in Patients With a Fontan Circulation - A Multicenter Study

Conditions
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Lymphatic Abnormality, Plastic Bronchitis, Protein-Losing Enteropathies, Univentricular Heart, Congenital Heart Disease

Intervention / Treatment
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* Diagnostic Test: Non-contrast MRI
* Diagnostic Test: Cardiopulmonary exercise test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Fontan Circulation Exclusion Criteria: Age <18 years Mental illness Genetic syndromes

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Fontan Group<br>Fontan patients operated at the two centres between 1991 and 2014. | Diagnostic Test: Non-contrast MRI<br>* Classification and characterization of the lymphatic vasculature using non-contrast MRI.<br>Diagnostic Test: Cardiopulmonary exercise test<br>* Cardiopulmonary exercise test, measurement of VO2 and heart rate.<br>|
| Healthy Control Group<br>Age, gender and weight matched healthy controls. | Diagnostic Test: Non-contrast MRI<br>* Classification and characterization of the lymphatic vasculature using non-contrast MRI.<br>Diagnostic Test: Cardiopulmonary exercise test<br>* Cardiopulmonary exercise test, measurement of VO2 and heart rate.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lymphatic classification | Classified by third party, according to following: (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542623/) | 1 hour | 
| Relative measure of tortuosity | Straight length/full length (mm/mm) | 1 hour | 
| Measurement of thoracic duct volume | Volume (mm^2) | 1 hour | 
| Measurement of thoracic duct diameter | Diameter at inlet (mm) | 1 hour | 
| The International Physical Activity Questionnaire (IPAQ-SF) | IPAQ-SF estimation of weekly activity. (Total Physical Activity min/wk: 2 × time spent on vigorous + moderate + walking) Higher value equals higher level of activity. | 1 hour | 
| CPX heart rate | Maximum heart rate (bpm) | 1 hour | 
| CPX Vo2 | VO2 max | 1 hour |