There is evidence that BNP and NT-proBNP serum levels are influenced by conditions related to prematurity, such as respiratory distress syndrome (RDS), pulmonary hypertension, and BPD [39,40,41], ROP [42,43], sepsis [40,44], and particularly by hsPDA [45,46,47,48,49,50,51,52,53,54,55]. Here, NPPB is linked to pulmonary arterial hypertension.