The cardiorenal syndrome: a mutual approach to concomitant cardiac and renal failure.

Heart failure (HF) accompanied by renal failure, termed cardiorenal syndrome (CRS), encompasses both the development and worsening of renal insufficiency secondary to HF as well as the harmful effects of impaired renal function on the cardiovascular system, and remains a universalclinical challenge. CRS was recently classified into subtypes depending on the etiologic and chronologic interactions between cardiac and renal dysfunctions. The mechanisms underlying the CRS are multifactorial, including hemodynamic alterations, neurohormonal effects, and inflammatory components. However, despite enhanced understanding and awareness of CRS, further elucidation of the mechanisms involved and the appropriate treatment approaches are clearly warranted. CRS is a difficult condition to manage, as treatment to relieve congestive symptoms of HF is limited by a further decline in renal functions, itself a major independent predictor of long-term cardiac morbidity. In order to perform a proper clinical investigation and implement appropriate treatmentthat will minimize subsequent progression of heart and kidney injury, a comprehensive approach to these two pathologies is crucial. In the present review we discuss current theories behind the mechanistic evolution of the CRS as well as therapeutic issues regarding this multifaceted condition.