Short- and long-term individual variation in NT-proBNP levels in patients with stable coronary artery disease

Abstract

BackgroundIn addition to diagnosis of heart failure (HF) natriuretic peptides (BNP and NT-proBNP) may be used for risk prediction in stable and acute coronary artery disease. The aim of the study was to evaluate the short- and long-term individual variation of NT-proBNP in patients with stable coronary artery disease. MethodsTwenty-four patients with suspected stable coronary artery disease and scheduled for elective coronary angiography were included. Blood samples were drawn at enrolment and, on average 3weeks later, serially the day prior to coronary angiography. NT-proBNP was determined using Elecsys proBNP sandwich immunoassay (Roche Diagnostics). ResultsThe individual variation in NT-proBNP over 4h was 11.8%, over 20h 12.4% and over 3weeks 20.4%. The corresponding positive and negative lognormal reference change values (RCV) were +41/−29%, +42/−30% and +76/−43%, respectively. No significant circadian variation was found. ConclusionsOur results suggest that an increase in NT-proBNP levels of >42% or a decrease of >30% is needed to indicate a reliable short-term change; and for a long-term change an increase of >76% or a decrease of >43% is required. This should be considered when interpreting changes in NT-proBNP levels.