Renal dysfunction prevalence and clinical impact in heart failure Alberto Palazzuoli, Susanna Benincasa, Stefanie Grothgar, Pasquale Di Sipio, Giovanni Paganini, Marco Pellegrini, Ranuccio NutiDepartment of Internal Medicine and Metabolic Diseases, Cardiology Section, Le Scotte Hospital, University of Siena, ItalyAbstract: Chronic kidney disease (CKD) is associated with a significant increase in death and cardiovascular mortality. However the exact mechanism by which CKD impairs the cardiovascular outcome is not well established. Some reasons may lie in the association of CKD with several other cardiovascular and noncardiovascular disorders including accelerated systemic atherosclerosis, endothelial dysfunction, increased levels of inflammatory factors, anemic status, bone mineral dysfunction, electrolyte imbalance, and renin–angiotensin–aldosterone system (RAAS) activation. Therefore several risk factors such as hypertension, diabetes, lipid disorders, and older age are common in both conditions. In patients affected with heart failure (HF) a key role is represented by the neurohormonal activation. This condition causes fluid and sodium retention, peripheral vasoconstriction, as well as increased congestion and cardiac workload. Moreover, HF during the decompensated phases is often associated with a worsening renal function that leads to further RAAS activation, microvascular damage, and intrarenal flow redistribution. In order to clarify the interactions between these factors, several questions need to be answered: the universal definition of “worsening renal function,” the identification of the best laboratory parameters to investigate renal function in terms of sensitivity and specificity, and a better definition of the comorbidities’ role in the determination of the outcome, especially in patients with chronic HF. A clarification of these key points could lead to the individualization of new specific therapeutic targets and to a reduction in mortality and hospitalization in patients with HF and renal impairment.Keywords: heart failure, outcome, renal insufficiency, worsening renal function