Natriuretic peptides in the elderly. Implications for morbidity and mortality

Abstract

Aim: Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are potent natriuretic and vasodilating hormones released from the heart in response to myocardial stretch. In the present thesis, the aim was to investigate the relationship between ANP, the amino-terminal part of proANP (Nt pro-ANP) and BNP, and cardiovascular morbidity and mortality in an 85-year-old population. The prevalence of cardiovascular diseases in this elderly population have been studied and risk factors and risk indicators in the congestive heart failure patients have been analyzed.Methods: The elderly population studied was derived from the longitudinal population study of "70-year-old people in Gothenburg, Sweden". This thesis deals with the population born in 1901/02 (cohort I) and natriuretic peptides have been measured at the age of 85 in 545 individuals. Plasma concentrations of ANP were determined by radioimmunoassay (RIA) and immunoradiometric assay (IRMA). Nt pro-ANP was determined by RIA and BNP by IRMA. Results: In the 85-year-olds, cardiovascular diseases are common and affect 46% of the population. Hypertension and atrial fibrillation at previous investigations were associated with the development of congestive heart failure at the age of 85. Patients with the diagnosis of congestive heart failure, ischaemic heart disease and atrial fibrillation had increased plasma concentrations of ANP, Nt pro-ANP and BNP. Increased plasma concentrations of ANP, Nt pro-ANP and BNP were accompanied by an increased prospective 5 year mortality rate in the population with cardiovascular diseases as well as in the total 85-year-old population. In the population without defined cardiovascular diseases, Nt pro-ANP and BNP predicted mortality prospectively.Conclusion: In the elderly, cardiovascular diseases are common and associated with increased plasma concentrations of natriuretic peptides. Plasma levels of natriuretic peptides predicted an increased mortality rate in patients with cardiovascular diseases and also in the patient group without defined cardiovascular diseases.