Natriuretic Peptides in Heart Failure

Heart failure is a major global health problem affecting 23 million people worldwide. As more cardiac patients survive and live longer with this progressive disease, heart failure is a condition for which the prevalence will grow. Based solely on clinical presentation, heart failure can be difficult to diagnose since its presentation is complex, with signs and symptoms that are nonspecific and may not always be present. B-type natriuretic peptide (BNP)7 and N-terminal proBNP (NT-proBNP) are well established, clinically validated biomarkers that have been shown to improve the diagnostic accuracy for heart failure and provide prognostic information for risk stratification. The widespread clinical use of these biomarkers for more than a decade is reflected by their incorporation into national and international medical guidelines for heart failure, at the highest classification for recommendation. BNP is a cardiac hormone secreted by cardiomyocytes into the circulation in response to states of volume expansion and pressure overload, as is the case in heart failure. BNP's diuretic, natriuretic, and vasodilatory actions, and its protective effects on endothelial function and vascular remodeling, act to relieve the adverse consequences of heart failure. During the synthesis and processing of BNP, its 108 amino acid biologically inactive precursor, proBNP, is proteolytically cleaved to form the 32 amino acid peptide BNP and the 76 amino acid peptide NT-proBNP. While BNP is physiologically active, NT-proBNP is biologically inert. Due to its secretion at a 1:1 ratio to BNP and its longer half-life (90–120 min vs 20 min for BNP), the measurement of NT-proBNP has proven to have an essentially equivalent clinical performance to BNP as a biomarker for heart failure.