Abstract 14275: Feasibility and Efficacy of Negative Pressure Ventilation in the Ambulatory Fontan Population- (FONTAN-CMR)- A Pilot Study.

Introduction: Fontan operation is the procedure of choice for children born with single ventricle physiology. Despite successful pediatric survival, rates of morbidity and mortality are high in adult Fontan survivors due to a chronically low cardiac output (CO). Treatment options for Fontan failure are limited. While short-term augmentation of CO with negative pressure ventilation (NPV) immediately following Fontan surgery has been shown, the effects of NPV in the ambulatory setting have not been studied. Our aim is to explore safety, feasibility and efficacy of a novel, portable external NPV (United Hayek Medical) in the Fontan population. Hypothesis: NPV will improve CO as measured by cardiovascular magnetic resonance imaging (CMR). Methods: Inclusion criteria: Adults (> 18y) with lateral tunnel or extracardiac Fontan and a dominant left ventricle with age-matched healthy controls. Exclusion criteria: Patients with failing Fontan physiology, significant valve regurgitation/stenosis, obstruction within the Fontan circuit, SO2 <90%, obesity (BMI > 35 kg/m2), chest wall deformities and/or contraindications to CMR. CMR flow measurements were obtained at multiple locations (ascending(AsAo) & descending aorta (DaAo), pulmonary arteries (RPA & LPA), vena cavae and Fontan circuit) at baseline and at various time points and pressure settings (Figure 1). Flow measurements expressed in L/min/m2. Data analyzed using Wilcoxon Mann-Whitney test. Results: A total of 20 subjects were enrolled: 10 Fontan and 10 controls. At baseline, Fontan patients have decreased cardiac index (CI) compared to controls. Brief application (10 min) of NPV resulted in significant increase in CI from 2.65 to 3.26 L/min/m2 (23% mean increase) in the Fontan group as compared to no effect in controls (Figure 2). Among the two ventilator modes biphasic mode (BCV) is more effective and well tolerated (Figure 3). Conclusions: A significant improvement in CO can be achieved in adult Fontan patients using NPV in the ambulatory setting. [ABSTRACT FROM AUTHOR]