Natriuretic peptides (NP) are well-validated aids in the diagnosis of acute decompensated heart failure (ADHF). In acute presentations, both brain natriuretic peptide (BNP) and N-terminal of the prohormone brain natriuretic peptide (NT-proBNP) offer high sensitivity (>90 %) and negative predictive values (>95 %) for ruling out ADHF at thresholds of 100 and 300 pg/ml, respectively. Plasma NP rise with age. For added rule-in performance age-adjusted thresholds (450 pg/ml for under 50 years, 900 pg/ml for 50–75 years and 1,800 pg/ml for those >75 years) can be applied to NT-proBNP results. Test performance (specificity and accuracy but not sensitivity) is clearly reduced by renal dysfunction and atrial fibrillation. Obesity offsets the threshold downwards (to ~50 pg/ml for BNP), but overall discrimination is preserved. Reliable markers for impending acute kidney injury in ADHF constitute an unmet need, with candidates, such as kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin, failing to perform sufficiently well, and new possibilities, including the cell cycle markers insulin growth factor binding protein 7 and tissue inhibitor of metalloproteinases type 2, remain the subject of research.
A Mark Richards - Christchurch Heart Institute, University of Otago, Christchurch, New Zealand; Cardiovascular Research Institute, National University of Singapore, Singapore.