NPPB and heart failure: It should also be mentioned that there occurs a progressive increase in the levels of some vasodilatory natriuretic peptides (ANP and BNP) as well as endothelial nitric oxide (NO) in the circulation to maintain hemodynamic homeostasis; in fact, both ANP and BNP are commonly used as biomarkers for characterization of the heart failure stage [34,35,36].