NPPB and Patent ductus arteriosus: The serum NT-proBNP values of the two groups of neonates were analyzed, and it was found that the serum NT-proBNP in the PDA group was significantly higher than that in the APDA group after 3d and 5d of birth, which was similar to the research results of Sellmer et al.11 The reason may be that the left ventricular volume and pressure load increased during the transition from fetal circulation to postpartum circulation, resulting in increased NT-proBNP secretion.