Diagnostic value of N-terminal pro-brain natriuretic peptide in pleural effusions of cardiac origin.

INTRODUCTION: The diagnosis of cardiogenic pleural effusion (PE) is often difficult to make. The objective of our study was to evaluate the diagnostic usefulness of N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in PE patients with heart failure, in pleural fluid (PF) and blood (B), and to compare the cholesterol in pleural fluid (CHOL PF) and in serum (CHOL S) with the Light criteria.

PATIENTS AND METHODS: All the biomarkers were evaluated in 398 PF (26.9% transudates). The area under the curve (AUC) quantified the overall diagnostic precision. The diagnostic precision of the different parameters was also assessed using the ROC curves.

RESULTS: The AUC of the ROC for pleural fluid NT-proBNP was 0.894, with no significant differences with CHOL PF (0.914) or with the Light criteria (0.896). The sensitivity, specificity, the positive probability ratio (PPR) and negative probability ratio (NPR) were 85.1% (94.1% for CHOL PF), 79.9% (90.2% for the Light criteria), 4.24 (7.27 for the Light criteria) and 0.19 (0.07 for CHOL PF), respectively. The combination of NT-proBNP in PF ≥ 276 pg/ml and CHOL PF ≤ 57 mg/dL managed to classify the highest number PE correctly (sensitivity 97.8%, specificity 85.4%).

CONCLUSIONS: The diagnostic yield of NT-proBNP in cardiogenic PE is not superior to the CHOL LP or the Light criteria, although it could be diagnostic in transudates of another origin.