Feasibility and Efficacy of Portable Non-invasive Negative Pressure Ventilation in Fontan Patients

Study Overview
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Brief Summary
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The human heart has 4 chambers: 2 collecting chambers (atria) and 2 pumping chambers (ventricles) to allow blood flow within two distinct circuits: pulmonary and systemic. The pulmonary circuit directs the blood to the lungs to receive oxygen and the systemic circuit delivers oxygen-rich blood throughout the body. In children born with a single ventricle, blood from these two circuits mixes within the heart resulting in lower oxygen levels in the blood delivered to the body (cyanosis). The Fontan procedure is a palliative surgery which bypasses the need for a ventricle to deliver blood to the lungs, as blood from the body flows passively to the lungs by a man-made connection (whereby two large body veins [cavae] are sewn to the pulmonary arteries), thereby preventing mixing of blood through restoration of two distinct circuits without mixing of blood. Although the Fontan operation effectively eliminates cyanosis and enables survival into adulthood, increased systemic venous pressure is an unavoidable systemic complication and low cardiac output (CO) is pervasive finding. Despite excellent pediatric surgical results, the risk of late complications and death dramatically increases in the decades following Fontan surgery. A chronically low CO state secondary to decreased forward flow of blood to the lungs can result in end-organ dysfunction and shortened life expectancy. Short of heart transplantation, deemed suitable only for a minority of patients, effective therapies for low CO are largely absent. The investigators aim to investigate a novel, non-invasive, ambulatory therapy which can augment CO. Specifically, external suction is applied intermittently to the chest wall, much like a vacuum, to increase CO, called negative pressure ventilation (NPV) using a Cuirass® ventilator (Hayek Medical). Although used in patients with lung disease, the investigators' proposal is to evaluate this novel, portable, ventilation system would be the first study of its kind in adults with congenital heart disease, specifically those with a Fontan palliation.

Official Title
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Feasibility and Efficacy Of Negative Pressure Ventilation in Fontan populatioN: Cardiovascular Flow Assessment by Magnetic Resonance Imaging

Conditions
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Fontan Physiology

Intervention / Treatment
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* Device: Hayek RTX ventilator


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fontan patients age > 13 years. Exclusion Criteria: unable to complete MRI (pacemaker/defibrillator/retained wires, pregnancy, claustrophobia); evidence of Fontan failure (requiring ongoing medical / device therapy) protein-losing enteropathy, intracardiac thrombus, anatomical obstruction to the Fontan circuit; patent Fontan fenestration; oxygen saturation < 90%; ongoing arrhythmia; ejection fraction < 50% on echocardiography or CMR; moderate or severe valve insufficiency on echocardiography or CMR; Obesity (BMI >35); severe obstructive sleep apnea (AHI>20); chronic obstructive lung disease (FEV1/FVC<60%); severe chest wall deformities (scoliosis, kyphosis, kyphoscoliosis); acute or chronic kidney disease (eGFR<60) unable to provide informed consent.

Ages Eligible for Study
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Minimum Age: 13 Years
Maximum Age: 55 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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Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This is a cross-sectional study designed to evaluate the immediate impact of negative pressure ventilation (NPV) in an ambulatory Fontan population using cardiovascular magnetic resonance imaging (CMR) for assessment of cardiovascular flows.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Fontan patient population<br> | Device: Hayek RTX ventilator<br>* Negative pressure ventilation in Fontan patients.<br>* Other names: Negative pressure ventilation;|
| Sham Comparator: Healthy volunteers<br> | Device: Hayek RTX ventilator<br>* Negative pressure ventilation in Fontan patients.<br>* Other names: Negative pressure ventilation;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Efficacy of the NPV on cardiac output | Cardiac output will be measured in L/min/m2 using phase contrast MRI. Flow measurements will be made at baseline and with application of the device. | 6-8 months | 
| Efficacy of the NPV on organ perfusion | Multi organ perfusion will be measured in L/min/m2 using phase contrast MRI. Flow measurements will be made at baseline and with application of the device. | 6-8 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tolerability and safety of negative pressure ventilation. | Assessed by participant questionnaire rating tolerance, safety, overall satisfaction with the device. | 6-8 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fontan operation, Negative pressure ventilation, MRI