Abstract 12034: Diffuse Myocardial Fibrosis, Its Distribution And Relationship To Clinical Outcome And Ventricular Function In Single Ventricles Before And After Fontan: A Cardiac Magnetic Resonance Outcome Study

Introduction: Patients with single ventricle (SV) anatomy are susceptible to myocardial fibrosis as measured by cardiac magnetic resonance (CMR) imaging. This study investigated the association of diffuse myocardial fibrosis prior to Fontan with ventricular function and clinical outcomes after Fontan completion. Methods: Retrospective cohort study of consecutive SV patients who underwent CMR T1 mapping prior to Fontan. Native T1 time and extracellular volume (ECV) of the dominant ventricle and a free wall region of interest (ROI) were measured on CMR pre-Fontan. Longitudinal strain was measured on echocardiography pre- and post-Fontan. Associations between pre-Fontan fibrosis, strain, and clinical outcomes were evaluated using linear and logistic regression. Results: 40 patients were included (table 1). ECV directly correlated to the number of ICU days and post-Fontan strain. The coefficient of variation (CV) of ECV directly correlated to hospital and chest tube days. When limited to single right ventricles (RV), T1 directly correlated to strain pre-Fontan. ECV directly correlated to ICU days as well as strain pre- and post-Fontan. ECV ROI directly correlated to strain post-Fontan. The CV of ECV directly correlated to the number of hospital days (table 2). Conclusions: Myocardial fibrosis prior to Fontan may portend the clinical course after Fontan and should be considered for risk stratification. The CV of ECV is a novel measure of diffuse fibrosis that is associated with clinical outcome. For single RV patients, fibrosis before Fontan is associated with worse ventricular function after. The use of reverse remodeling agents prior to Fontan should be considered.