Recent studies have also shown the applicability of serum NT-proBNP as a suitable biomarker in infants with BPD-PH.38–40 Based on our experience, especially in infants, absolute values of NT-proBNP have a high inter-individual variance, are strongly dependent on postnatal and gestational age, and thus have limited value in establishing the diagnosis or severity of PH, especially in young infants. This evidence concerns the gene NPPB and bronchopulmonary dysplasia.