Response to Sildenafil in Patients With Fontan Physiology, A Pressure-volume Loop Analysis

Modifications to surgical procedures and medical treatment have led to a rapidly declining mortality rates in patients with single-ventricle heart disease (SV). However, SV patients still suffer from lower quality of life, decreased exercise capacity, worse neurodevelopmental outcomes and many other morbidities. While patients with SV circulation only make a small portion of all congenital heart diseases, 2-4 %, they require a great deal of resource utilization. Standard medical treatments for adult heart failure have not had the same success in the SV population. Phosphodiesterase 5 (PDE5) inhibitors have recently become a frequently used medication class in patients with SV heart disease to treat pulmonary hypertension, heart failure, as well as "Fontan" failure (i.e., plastic bronchitis and protein-losing enteropathy). While there have been findings of improved measures of exercise capacity and some reports of improved symptoms of heart failure, the physiologic mechanisms behind these findings are not completely understood. There have been reports, indicating that the phosphodiesterase five inhibitors improve ventricular function in biventricular circulation patients and animal models. The aim of our study was to investigate the effect of acute PDE5 inhibition on ventricular function in SV patients after the final palliative surgery, the Fontan procedure.