Natriuretic Peptides and Troponins in Pulmonary Embolism: A Meta-analysis

In an effort to try to find accurate markers for pulmonary embolism (PE), different biomarkers have been investigated. This meta-analysis evaluated the prognostic significance of natriuretic peptides (BNP and NT-proBNP) alone or in combination with troponins in the diagnosis of PE. The study also evaluated the diagnostic accuracy of natriuretic peptides in determining right ventricular dysfunction in patients with PE. MEDLINE and EMBASE databases were searched for studies that reported patients with an objective diagnosis of PE. The studies were included in the meta-analysis if a 2×2 table could be constructed based on natriuretic peptide results. The studies included in the meta-analysis also had to evaluate at least one of the following four outcomes: all-cause mortality, PE-related mortality, serious adverse events, and right ventricular dysfunction. Twenty-three studies were included in the meta-analysis, totaling 1127 patients. Elevated natriuretic peptide levels were associated with all-cause mortality (odds ratio [OR] 6.2, 95% confidence interval [CI] 3.0–12.7), PE-related mortality (OR 5.0, 95% CI 2.2–11.5), and serious adverse events (OR 6.7, 95% CI 3.9–11.6), with homogeneity across studies. Overall, 52% (587/1127) of patients with PE had elevated natriuretic peptides. Among natriuretic peptide-positive patients, 46% (103/222) also had positive troponin values. The results were still significant in hemodynamically stable patients with homogeneity across studies for all-cause mortality (OR 6.9, CI 2.3–20.7) and PE-related mortality (OR 8.4, CI 2.1–33.4), but not for serious adverse events (OR 15.5, CI 0.8–284.7). The rates of all-cause mortality, PE-related mortality, and serious adverse events in natriuretic- and troponin-negative patients were 0.2% (1/443), 0% (0/341), and 1.6% (7/443), respectively. The authors concluded that higher levels of natriuretic peptides identified a subset of patients with PE at higher risk of adverse outcomes. Increased troponins in the setting of elevated natriuretic peptides were found to be an independent prognostic marker of worse outcomes.