Breathing Not Properly - BNP

Description:

The goal of the Breathing Not Properly (BNP) trial was to evaluate the use of B-type natriuretic peptide (BNP) as a diagnostic test for the diagnosis of heart failure (HF) and to compare BNP to physician assessment using Framingham and NHANES congestive heart failure (CHF) scores.

Study Design

Patients Screened: 1,666
Patients Enrolled: 1,538
Mean Patient Age: 18-105 years (mean 64 years)
Female: 44%

Patient Populations:

Presenting to the emergency departments with a primary complaint of dyspnea.

Exclusions:

Presence of advanced renal failure (calculated creatinine clearance <15 ml/min),="" acute="" myocardial="" infarction,="" and="" overt="" cause="" of="" dyspnea,="" including="" chest="" wall="" trauma="" or="" penetrating="" lung="" injury.="" ml/min),="" acute="" myocardial="" infarction,="" and="" overt="" cause="" of="" dyspnea,="" including="" chest="" wall="" trauma="" or="" penetrating="" lung="">

Primary Endpoints:

Diagnostic accuracy at the optimum cutoff of BNP and at &ge;80% emergency department physician estimate of clinical probability of CHF.

Drug/Procedures Used:

A total of 1,586 patients from seven centers were enrolled in the BNP Multinational Study between April 1999 and December 2000. BNP was measured in a blinded fashion in patients presenting to the emergency department with a primary complaint of dyspnea. The reference standard for CHF was adjudicated by two independent cardiologists who were also blinded to BNP results.

Principal Findings:

The final diagnosis was HF in 722 patients (47%) and no HF in 748 patients. Using a cutoff of 100 pg/ml, BNP had a sensitivity of 90% and specificity of 73%. BNP testing provided an accurate diagnosis in 81.2% of patients compared to 74.0% for clinical judgment overall. Adding BNP to physician decision would have increased the accuracy of diagnosis from 74.0% to 81.5% (p<0.0001). in="" addition,="" 427="" patients="" were="" among="" those="" in="" the="" "physician="" indecision"="" range="" when="" clinical="" judgment="" was="" used.="" using="" bnp="" testing="" at="" a="" cutoff="" of="" 100="" pg/ml="" correctly="" classified="" 74%="" of="" these="" indecision="" cases.="" the="" areas="" under="" the="" receiver="" operating="" characteristic="" curve="" were="" 0.86="" (95%="" confidence="" interval="" [ci]="" 0.84-0.88),="" 0.90="" (95%="" ci="" 0.88-0.91),="" and="" 0.93="" (95%="" ci="" 0.92-0.94)="" for="" clinical="" judgment,="" for="" bnp="" at="" a="" cutoff="" of="" 100="" pg/ml,="" and="" for="" the="" two="" in="" combination,="" respectively=""><0.0001 for="" each="" of="" the="" pairwise="" comparisons).="" in="" patients="" without="" a="" self-reported="" history="" chf="" (n="1,027)," diagnostic="" accuracy="" bnp="" was="" 80.4%.="">

Interpretation:

Among patients presenting to the emergency department with a primary complaint of dyspnea, use of BNP testing added to the clinical judgment diagnosis of CHF. These data show that BNP titers compare favorably in diagnostic accuracy to other HF diagnostic criteria. BNP has already been incorporated into European guidelines for CHF. In the AHA/ACC practice guidelines, however, the diagnosis of CHF is based on the established criteria of patient history, physical exam, electrocardiogram, echocardiography, and chest X-ray. Whether BNP will be incorporated into the ACC/AHA guidelines remains to be determined. It is likely that this test will be complementary to, rather than replace, the diagnostic tools already available to the clinician.

References:

McCullough PA, Nowak RM, McCord J. B-type natriuretic peptide and clinical judgment in emergency diagnosis of heart failure: analysis from Breathing Not Properly (BNP) Multinational Study. Circulation. 2002;106:416-22.

Clinical Topics: Heart Failure and Cardiomyopathies, Noninvasive Imaging, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Echocardiography/Ultrasound

Keywords: Diagnostic Tests, Routine, X-Rays, Heart Failure, Electrocardiography, Dyspnea, Atrial Natriuretic Factor, Echocardiography, Natriuretic Peptide, Brain


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