Natriuretic peptides and troponins in pulmonary embolism: a meta-analysis.

BACKGROUND The role of biomarkers such as B-type natriuretic peptides (BNP and NT-proBNP) and troponins in risk stratification of acute pulmonary embolism (APE) is still debated. A meta-analysis was performed to assess the association between raised natriuretic peptide levels, alone or in conjunction with troponins, and all-cause and APE-related mortality, serious adverse events and echographic right ventricular dysfunction. METHODS MEDLINE and EMBASE databases were searched and conference abstracts were hand searched up to February 2008. Studies were included if a 2x2 table could be constructed based on natriuretic peptide results and at least one of the outcomes. RESULTS Twenty-three studies were included (1127 patients). Raised natriuretic peptide levels were significantly associated with all-cause mortality (odds ratio (OR) 6.2; 95% confidence interval (CI) 3.0 to 12.7), APE-related mortality (OR 5.0; 95% CI 2.2 to 11.5) and serious adverse events (OR 6.7; 95% CI 3.9 to 11.6), with homogeneity across studies. Among patients with raised natriuretic peptide levels, increased serum troponins were associated with a further increase in the risk of adverse outcomes. Analysis of the accuracy of natriuretic peptides in detecting right ventricular dysfunction was limited by heterogeneity across studies. BNP appeared to have better sensitivity and specificity than NT-proBNP in detecting right ventricular dysfunction. CONCLUSIONS Raised levels of B-type natriuretic peptides identified a subset of patients with APE at higher risk of adverse outcomes. Among patients with raised natriuretic peptide levels, increased troponins were found to be an independent prognostic marker. The results of this meta-analysis may have important clinical implications in the management of APE.