Adult Congenital Heart Disease

It has long been recognized that manifestations of congenital heart disease extend beyond the cardiovascular system. The extracardiac ramifications of congenital heart disease are multifaceted and bidirectional. The intricate interplay between congenital heart physiology, bi- or univentricular heart function, early and/or ongoing cyanosis, surgical and residual sequelae, and multisystemic effects are increasingly appreciated. Examples include the well-characterized neurological, hematologic, respiratory, skeletal, and hepatic consequences of cyanosis1; thromboembolic complications in surgically palliated univentricular hearts2; and dysregulation of the autonomic nervous system in various forms of congenital heart disease.3Article p 2320 In the present issue of Circulation , Dimopoulos and associates4 provide original and important insights regarding the relationship between congenital heart disease and impaired renal function. They examine the prevalence of renal dysfunction across a wide-spectrum of adult congenital heart defects and explore implications on overall death rates. Heterogeneity of the Study PopulationA general and common challenge in congenital heart disease research that encompasses a broad spectrum of cardiac disorders is the complexity and marked heterogeneity of the study population. From a methodological perspective, there is often a trade-off between heterogeneity of the patient population and the precision of a given statistical inference. When the objective is to provide a global perspective on a novel association, such as renal dysfunction and death in adults with congenital heart disease, however, heterogeneity of the patient population may be advantageous. The nonrestrictive inclusion criteria enhance generalizability of the findings to a broad target population. Although the reported overall 9.3% prevalence of moderate to severe renal dysfunction must be interpreted within the context of a high-volume referral center, it reflects a wide spectrum of congenital heart disease subtypes.Heterogeneity of the study population also allows exploration of gradients …