Amino-terminal pro-brain natriuretic Peptide, renal function, and outcomes in acute heart failure: redefining the cardiorenal interaction?

OBJECTIVES

We sought to study the individual and integrative role of amino-terminal pro-brain natriuretic peptide (NT-proBNP) and parameters of renal function for prognosis in heart failure.

BACKGROUND

Amino-terminal pro-BNP and renal impairment both predict death in patients with heart failure. Worsening of renal function in heart failure even defines the "cardiorenal syndrome."

METHODS

Seven hundred twenty subjects presenting with acute heart failure from 4 university-affiliated medical centers were dichotomized according to NT-proBNP concentration and baseline glomerular filtration rate. In addition, patients were divided according to changes in renal function. The primary end point was 60-day mortality.

RESULTS

The combination of a glomerular filtration rate (GFR) <60 ml/min/1.73 m2 with an NT-proBNP >4,647 pg/ml was the best predictor of 60-day mortality (odds ratio 3.46; 95% confidence interval 2.13 to 5.63). Among subjects with an NT-proBNP above the median, those with a GFR <60 ml/min/1.73 m2 or a creatinine rise > or =0.3 mg/dl had the worst prognosis, whereas in subjects with a NT-proBNP below the median, prognosis was not influenced by either impaired renal function at presentation or the development of renal impairment during admission.

CONCLUSIONS

The combination of NT-proBNP with measures of renal function better predicts short-term outcome in acute heart failure than either parameter alone. Among heart failure patients, the objective parameter of NT-proBNP seems more useful to delineate the "cardiorenal syndrome" than the previous criteria of a clinical diagnosis of heart failure.