The clinical challenge of cardiorenal syndrome.

Abstract

Renal dysfunction is a common and progressive complication of chronic heart failure, with a clinical course that typically fluctuates with the patient’s clinical status and treatment. Despite growing recognition of the frequent presentation of combined cardiac and renal dysfunction, or “cardiorenal syndrome,” its underlying pathophysiology is not well understood, and no consensus as to its appropriate management has been achieved. Because patients with heart failure are surviving longer and dying less frequently from primary arrhythmia, we expect that the cardiorenal syndrome will become more common. Against this background, the article by Wang and colleagues1 in the present issue of Circulation is particularly significant because it is the first prospective, controlled therapeutic trial in patients with this condition. To place the findings and implications of this study in context, we first briefly review what is currently known about the cardiorenal syndrome and its treatment options. See p 1620 In ambulatory heart failure patients, the presence of concomitant renal dysfunction consistently has been one of the strongest risk factors for mortality.2–4 This risk becomes evident even at serum creatinine clearance levels >1.3 mg/dL and estimated creatinine clearance values ≤60 to 70 mL/min. Furthermore, renal function is at least as powerful an adverse prognostic factor as most clinical variables, including ejection fraction and New York Heart Association function class. Although renal dysfunction predicts all-cause mortality, it is most predictive of death from progressive heart failure, which suggests that it is a manifestation of and/or exacerbating factor for left ventricular dysfunction.2 In the setting of hospitalization for decompensated heart failure, worsening renal function is even more important than baseline renal function for predicting adverse outcomes.5–8 Although any increase in creatinine is associated with poorer survival rates, longer hospitalization, and more frequent readmission, several studies have used a threshold of a …