The vicious cycle of intradialytic hypotension, inflammation and myocardial Stunning: Overview of pathophysiological aspects

Abstract

Intradialytic hypotension (IDH) represents a well-known and intractable complication in hemodialysis patients. Despite the innovations in hemodialysis techniques, its tenacious presence indicates the complexity of underlying pathophysiological mechanisms. The need of an integrated approach in understanding its pathogenesis is thought to be imperative as it may prevent devastating consequences through the implementation of more successful avoidance tactics. It is well established that IDH has been associated with impaired myocardial function and peripheral vascular resistance, attributed to either the hemodialysis procedure per se or patients' unique features. This review aims to describe traditional risk factors of IDH and focus on non- traditional but crucial factors of hemodynamic instability related to endothelial dysfunction. In particular, chronic subclinical inflammation may be considered the missing link in the vicious cycle of IDH, ischemia and myocardial stunning. Repeated episodes of enteric ischemia during hemodialysis represent an additional source of chronic systemic inflammation that induces the phenomenon of bacterial or endotoxin translocation through the impaired enteric epithelial cell barrier. Thus, increased endothelial dysfunction and oxidative stress result in decreased left ventricular pumping function and finally permanent systolic dysfunction through genetic adaptations. In total, these pathophysiological mechanisms preserve the vicious cycle of IDH.