Cardiorenal syndrome in acute heart failure: a vicious cycle?

Worsening renal function has an unquestionably negative impact on prognosis in patients with acute heart failure (HF). In Portugal there is little information about the importance of this entity in HF patients admitted to hospital. The objective of this work was to assess the prevalence of cardiorenal syndrome and to identify its key predictors and consequences in patients admitted for acute HF.

This was a retrospective study of 155 patients admitted for acute HF. Cardiorenal syndrome was defined as an increase in serum creatinine of ≥26.5 μmol/l. Clinical, laboratory and echocardiographic parameters were analyzed and compared. Mortality was assessed at 30 and 90 days.

Cardiorenal syndrome occurred in 46 patients (29.7%), 5.4 ± 4.4 days after admission; 66.7% (n=24) did not recover baseline creatinine levels. The factors associated with cardiorenal syndrome were older age, chronic renal failure, moderate to severe mitral regurgitation, higher admission blood urea nitrogen, creatinine and troponin I, and lower glomerular filtration rate. Patients who developed cardiorenal syndrome had longer hospital stay, were treated with higher daily doses of intravenous furosemide, and more often required inotropic support and renal replacement therapy. They had higher in-hospital and 30-day mortality, and multivariate analysis identified cardiorenal syndrome as an independent predictor of in-hospital mortality.

Renal dysfunction is common in acute HF patients, with a negative impact on prognosis, which highlights the importance of preventing kidney damage through the use of new therapeutic strategies and identification of novel biomarkers.