NPPB and pulmonary hypertension: At present, NT-proBNP is relevant to various neonatal diseases, such as pulmonary hypertension (6, 7), PDA (8–14), valular diseases (15), respiratory distress syndrome (16), bronchopulmonary dysplasia (BPD) (7, 17, 18), and retinopathy of prematurity (19, 20).