Natriuretic peptides: physiologic and analytic considerations.

Natriuretic peptides play a central role in cardiovascular, endocrine, and renal homeostasis and can be considered physiologic antagonists to the renin-angiotensin-aldosterone system. ANP and BNP in the circulation are derived primarily from the myocardium, whereas CNP is mainly derived from endothelial cells and the central nervous system. Increased ventricular and atrial diastolic wall stretch augment synthesis and release of BNP and NT-proBNP from cardiomyocytes, and is the principal stimulus controlling BNP production. Circulating BNP and NT-proBNP levels are increased in heart failure in proportion to disease severity, but elevated levels may also be observed in other cardiac and noncardiac disease states, including cardiac arrhythmias, ventricular hypertrophy, myocardial ischemia, pulmonary embolism, acute and chronic cor pulmonale, renal failure, anemia, hyperthyroidism, and sepsis. Fully automated analyses of both BNP and NT-proBNP can be rapidly performed on large hospital-based platforms as well as on small point-of-care devices.