BNP, troponin I, and YKL-40 as screening markers in extremely preterm infants at risk for pulmonary hypertension associated with bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is often complicated by pulmonary hypertension (PH). We investigated three biomarkers potentially suitable as screening markers for extremely preterm infants at risk of BPD-associated PH. In this prospective observational cohort study conducted in a tertiary neonatal intensive care unit, 83 preterm infants with BPD born <28-wk gestation and still inpatients at 36-wk corrected age received an echocardiogram and blood tests of B-type natriuretic peptide (BNP), troponin I, and YKL-40. Infants were analyzed according to echocardiographic evidence of tricuspid regurgitation (TR). Thirty infants had evidence of TR on echocardiogram at 36-wk corrected age. Infants with or without TR had similar baseline demographics: mean ± SD gestational age 261 ± 12 vs. 261 ± 11 wk and birth weight 830 ± 206 vs. 815 ± 187 g, respectively. There was no difference in duration of respiratory support. The right ventricular systolic pressure of infants with evidence of TR was 40 ± 16 mmHg. BNP was the only biomarker that proved to be significantly higher in infants with evidence of TR: median (interquartile range) serum level 54.5 (35-105) vs. 41.5 (30-59) pg/ml, P = 0.043. Subgroup analysis of infants with severe BPD requiring discharge on home oxygen or BPD-related mortality revealed similar results. There was no difference between groups for troponin I and YKL-40. In conclusion, increased serum levels of BNP were associated with evidence of TR at 36-wk corrected gestational age in extremely preterm infants, suggesting a potential role as a screening biomarker for BPD-associated PH.