Natriuretic Peptides as Markers of Mild Forms of Left Ventricular Dysfunction: Effects of Assays on Diagnostic Performance of Markers

BACKGROUND: We compared the performance of different natriuretic peptides to diagnose mild forms of left ventricular dysfunction (LVD) and investigated the influence of measuring B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) with different assays on the diagnostic performance of these markers. METHODS: We measured BNP (Triage BNP), NT-proBNP (Biomedica), and N-terminal pro-A-type natriuretic peptide (NT-proANP; Biomedica) in 130 consecutive patients (age range, 28-83 years) with clinically suspected mild LVD. In patients with sufficient sample volume, we measured BNP and NT-proBNP with additional assays (Shionoria and Roche, respectively). RESULTS: For identifying patients with mild systolic LVD, BNP and NT-proBNP were the best markers, with mean (95% confidence interval) areas under the curves (AUC) of 0.78 (0.63-0.89) and 0.75 (0.58-0.87), respectively. However, the diagnostic performance of NT-proANP AUC, 0.64 (0.48-0.77) was significantly worse than that of BNP (P = 0.014). Both BNP assays (Triage and Shionoria) and both NT-proBNP assays (Biomedica and Roche) performed equally well for the diagnosis of systolic LVD despite the poor agreement between NT-proBNP assays. In patients with isolated diastolic LVD, the diagnostic performance of the Triage BNP AUC, 0.70 (0.56-0.81) was significantly better (P = 0.006) than that of Biomedica NT-proBNP 0.49 (0.34-0.65). Furthermore, the performance of the Biomedica NT-proBNP assay was significantly worse (P = 0.03) than that of the Roche NT-proBNP assay for diagnosis of isolated diastolic LVD. CONCLUSIONS: The performance of BNP for the diagnosis of systolic or diastolic LVD is not affected by the assay used, whereas the performance of NT-proBNP for the diagnosis of isolated diastolic LVD is assay dependent.