The acute cardiorenal syndrome type I: considerations on physiology, epidemiology, and therapy.

Acute cardiorenal syndrome, also known as cardiorenal syndrome type 1, is defined as an abrupt worsening of cardiac function that occurs in at least 30 % of patients with acute decompensated heart failure and can lead to the development of acute kidney injury. The changes in renal function that occur in this setting have variable prognostic implications, as both poorer and better outcomes have been reported when renal function worsens during treatment of heart failure decompensation. Furthermore, it remains unclear when worsening renal function is actually a manifestation of true acute kidney injury or simply an indicator of hemoconcentration. Given these gaps in the understanding of the significance of renal function changes in the setting of decompensated heart failure, it is not surprising that studies on the effects of available therapies, including diuretics, vasoactive drugs, and mechanical fluid removal have yielded inconsistent results. The purpose of this review is to analyze critically the current knowledge on the pathophysiology, epidemiology, prognosis, and treatment of acute cardiorenal syndrome.