The advantages of our study are the prospective design and randomized treatment of very preterm infants with PDA diameter > 1.5 mm in the first 3 days of life, that allowed to eliminate the subjective factor in making management decisions, and objectively assess the predictive value of systemic NT-proBNP concentrations for the development of BPD or death in infants with PDA. Here, NPPB is linked to bronchopulmonary dysplasia.