B-type natriuretic peptide levels in preterm neonates with bronchopulmonary dysplasia: A marker of severity?

RATIONALE FOR THE STUDY: B type natriuretic peptide (BNP) is a hormone released in response to stretching of the ventricular wall. The role of BNP as a biomarker of bronchopulmonary dysplasia (BPD) has not been clarified. OBJECTIVE: To determine if plasma BNP concentrations correlate with the severity of BPD. METHODS: This prospective observational case control study included 60 preterm infants (≤32 weeks); 27 infants had no/mild BPD, 19 had moderate and 14 had severe BPD. BNP levels were measured at 36 ± 2 weeks PMA or within a week of discharge home. Groups were compared using Mann-Whitney's U-test, Kruskal-Wallis, and bivariate regression. RESULTS: Median (IQR) plasma levels of BNP in infants with moderate/severe BPD infants (n = 33) were higher as compared to those with no/mild BPD (n = 27); 27.1 (12.1-43.5) pg/ml versus 9.3 (6-18.5) pg/ml; P < 0.05 (Mann Whitney U). Median (IQR) BNP levels in infants with severe BPD (n = 14), 43.5 (28.4-189) pg/ml differed significantly from levels in those with moderate (n = 19), 22.8 (10.3-27.7) pg/ml; mild (n = 16), 11.5 (6.6-44.5 pg/ml); or no (n = 11), 8.1 (5-12.6 pg/ml) BPD (P < 0.001 Kruskal-Wallis). Based on receiver operating characteristic curves, BNP > 24.4 pg/ml at 36 ± 2 weeks PMA or discharge home was 85.7% sensitive and 76.1% specific for severe BPD. CONCLUSIONS: An elevation in plasma BNP was significantly associated with severe BPD. We speculate that plasma BNP measurement in infants with BPD may aid in risk-stratification and further targeted therapies.