NPPB and Patent foramen ovale: It may be caused by the left to right atrial shunt caused by PDA in neonatal patent foramen ovale at three days of birth, reducing the volume load of the left atrium.10 These results suggested that neonatal serum NT-proBNP level can better reflect the changes of cardiac volume load than clinical symptoms, and may be a quantitative indicator of arterial shunt, which can reflect the hemodynamic changes of neonates with PDA.