The Relentless Effects of the Fontan Paradox.

The Fontan operation is the anticipated palliative strategy for children born with single-ventricle type of congenital heart disease. As a result of important circulatory limitations, a series of end-organ complications are now increasingly recognized. Elevated central venous pressure and impaired cardiac output are the hallmarks of cavo-pulmonary flow, which result in a cascade of pathophysiological consequences. The Fontan circulation likely impacts all organ systems in an indolent and relentless manner, with progressive decline in functionality likely to occur in many. Liver fibrosis, altered bone density, decreased muscle mass, renal dysfunction, lymphatic insufficiency, and a host of other conditions are present. Standardized screening and evaluation of survivors as they grow through childhood and beyond is indicated and can be facilitated through dedicated multidisciplinary clinical programs. Invasive assessment at specific milestones can provide important actionable information to optimize individual status. More detailed characterization and understanding of these end-organ complications is necessary to contribute to the goal of achieving a normal duration and quality of life for these unique individuals.