A Prospective, Blinded Trial of B-Type Natriuretic Peptide as a Diagnostic Test for the Emergency Diagnosis of Heart Failure: The Breathing Not Properly (BNP) Multinational Study
Peter A. McCullough
University of Missouri - Kansas City
Kansas City, MO, USA

In this large study, B-type natriuretic peptide was useful as a predictor of congestive heart failure in patients presenting to the emergency department with dyspnea. Measurement of this neurohormone adds predictive power to traditional evaluation. In addition, a single measurement reduced clinical indecision by 74%.

Recent surveys have suggested the development of a chronic disease epidemic of heart failure in recent years. Yet diagnostic procedures for congestive heart failure have remained unchanged for decades.

A cardiac neurohormone, B-type natriuretic peptide, is specifically secreted from cardiac ventricles. This occurs in response to pressure overload, ventricular volume expansion, and increased wall tension. Multiple reports have found a correlation between elevated blood levels of B-type natriuretic peptide and congestive heart failure.

In 2000, the U.S. Food and Drug Administration approved use of B-type natriuretic peptide as a diagnostic aid. However, ACC/AHA guidelines for 2001 state that the role of this neurohormone in patients with congestive heart failure "remains to be fully clarified."

The Breathing Not Properly (BNP) Multinational study included 1,586 patients who presented to the emergency department with dyspnea. Investigators used a 15 minute blood test to evaluate blood levels of B-natriuretic peptide.

They conducted the blood test using a device about the size of a desktop calculator (Triage BNP Test, Biosite, Inc.). This was the first prospective efficacy study for this rapid B-natriuretic peptide test in emergency department evaluation of dyspnea.


B-natriuretic peptides, at a cutoff of 100 pg/mL, had a sensitivity of 90%, specificity of 74%, and accuracy of 81.1% for differentiating congestive heart failure from other dyspnea causes.

The primary endpoint of this study was diagnostic accuracy vs. clinical evaluation. Results showed that B-natriuretic peptide measurements were more accurate than clinical evaluation (81% vs. 74%, P < 0.0001).


By multivariate analysis, investigators found the B-natriuretic peptide measurement added significant predictive power to history, physical examination, chest X-ray and other traditional components of evaluation.

Researchers used a Bayesian analysis to determine the incremental effect of a single B-natriuretic peptide test when clinicians are unsure of the diagnosis. A single B-natriuretic peptide evaluation reduced clinical indecision by 74%.

B-natriuretic peptide levels reflected New York Heart Association functional class in subjects with heart failure.

Based on these results, heart failure guidelines should incorporate measurement of B-natriuretic peptide for the clinical diagnosis of heart failure.


Reporter: Andrew Bowser