Pathogenesis and therapeutic implications of cardiorenal syndrome.

Chronic kidney disease (CKD) is now widely accepted as a risk factor for cardiovascular disease and mortality. Heart failure patients with CKD have a worse prognosis. The heart and kidneys act in tandem to regulate blood pressure, vascular tone, diuresis, natriuresis, intravascular volume homeostasis, peripheral tissue perfusion, and oxygenation. Cardiorenal syndrome is a pathophysiological condition in which combined cardiac and renal dysfunction amplifies the progression of failure of the individual organs, and it has an extremely poor prognosis. The identification of patients and the pathophysiological mechanisms underlying each subtype will help physicians to understand the clinical derangements and provide the rationale for management strategies. The evidence from clinical trials conducted on heart failure patients with significant kidney dysfunction is insufficient because most patients are recruited from populations with relatively well-preserved kidney function. In severe volume-loaded patients who are refractory to diuretics and also have kidney dysfunction, the management of cardiorenal dysfunction is challenging, and effective therapy is lacking. In the absence of definitive clinical trials, treatment decisions must be based on a combination of information regarding the individual patient information and an understanding of the individual treatment options.