Cardiorenal syndrome in decompensated heart failure.

Worsening renal function during treatment of acute decompensated heart failure (ADHF) often complicates the treatment course of heart failure. Furthermore, the development of worsening renal function is a strong independent predictor of long-term adverse outcomes. Sometimes referred to as 'cardiorenal syndrome,' the definition varies widely, and the overall understanding of pathogenesis is limited. This is probably owing to the lack of precision and characterisation of renal compromise during treatment of heart failure. Traditionally, the predominant cause has been attributed to impairment of cardiac output and relative underfilling of arterial perfusion. Emerging data have led to a resurgence of interest in the importance of venous congestion and elevated intra-abdominal pressure rather than confining it to impaired forward cardiac output as the primary driver of renal impairment. These revived concepts may support the role of novel renal-sparing approaches to salt and water removal and renal preservation, but better ways to distinguish haemodynamic versus other nephrotoxic aetiologies are needed.