Plasma amino-terminal pro-brain natriuretic peptide: a novel approach to the diagnosis of cardiac dysfunction

Abstract

Background: Heart failure is a common cause of hospitalization and death across the industrialized world. Improving the diagnosis and care of patients with heart failure is therefore likely to have a major impact on morbidity, mortality, and health care costs.

Methods and results: To determine the relation between cardiac function and plasma levels of amino-terminal brain natriuretic peptide precursor (NT-proBNP), plasma NT-proBNP levels and ventricular function (by radionucleotide ventriculography) were measured in healthy patients, patients with renal failure, patients with recent myocardial infarction, and patients investigated for cardiorespiratory symptoms. Plasma NT-proBNP levels were greater in healthy women (median, 1.5 fmol/mL; range, 1.0 to 13.8 fmol/mL; n = 34) than healthy men (median, 1.0 fmol/mL; range, 1.0 to 3.3 fmol/mL; n = 33; P = .012). NT-proBNP levels were elevated in subjects with renal failure (geometric mean, 314 fmol/mL; range, 18 to 5,800 fmol/mL) and were related to left ventricular ejection fraction (LVEF) (r = -0.86; P < .0001; n = 19). NT-proBNP levels were also related to LVEF in patients with recent myocardial infarction (r = -0.62; P = .0003; n = 29) and those investigated for cardiorespiratory symptoms (r = -0.56; P < .0001; n = 129). Applying an upper limit of normal of 5 fmol/mL for men and 15 fmol/mL for women (specificity, 100%), elevated plasma NT-proBNP levels had 100% sensitivity for the detection of LVEF less than 45% after myocardial infarction and 97% sensitivity for the detection of LVEF less than 45% in patients investigated for cardiorespiratory symptoms. NT-proBNP levels were also elevated in 87% of the patients with normal systolic function (LVEF > or = 45%) after myocardial infarction and in 87% of the patients investigated for cardiorespiratory symptoms with heart failure and normal systolic function (LVEF > or = 45%).

Conclusions: Plasma NT-proBNP level is a sensitive indicator of cardiac dysfunction, both in the presence and absence of systolic dysfunction, and may prove to be a useful tool for the identification and management of cardiac dysfunction in the general community.