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.