Brain natriuretic peptide and n-terminal brain natriuretic peptide in the diagnosis of heart failure in patients with acute shortness of breath.
OBJECTIVE
This study sought to compare the utility of measurement of plasma brain natriuretic peptide (BNP) and N-terminal brain natriuretic peptide (N-BNP) in the diagnosis of heart failure (HF) in patients with acute dyspnea.


BACKGROUND
Plasma BNP is useful in differentiating HF from other causes of dyspnea in the emergency department. The N-terminal component of BNP has a longer half-life, and in HF increases in plasma N-BNP are proportionately greater.


METHODS
We studied 205 patients (average age 70 +/- 14 years) presenting to the emergency department with acute dyspnea. Brain natriuretic peptide was analyzed using a point-of-care test and two locally developed radioimmunoassays. N-terminal BNP was measured using a locally developed radioimmunoassay and a commercially available assay. Final diagnosis of HF was adjudicated by two cardiologists.


RESULTS
Patients with HF (n = 70) had higher mean levels of both hormones by all assays (p < 0.001 for all). Results with all assays correlated closely (r values between 0.902 and 0.969). Subjects with left ventricular (LV) dysfunction or left-sided valvular disease but no HF had intermediate levels of BNP and N-BNP (lower than subjects with HF, and higher than subjects without HF with no LV dysfunction or left-sided valvular disease) (p < 0.01 for all). Using optimum cut-offs, specificity for the diagnosis of HF ranged between 70% and 89% (highest for the N-BNP assays). Sensitivity ranged between 80% and 94% (highest for the point-of-care BNP assay).


CONCLUSIONS
Measurement of BNP or N-BNP is useful in the diagnosis of HF in acute dyspnea. Commercially available assays compare favorably with well-validated laboratory assays. Differences in sensitivity and specificity may influence the assay choice in this setting.
Lainchbury
John G
JG
Department of Medicine, Christchurch School of Medicine, University of Otago, Christchurch, New Zealand. john.lainchbury@chmeds.ac.nz
Campbell
Elizabeth
E
Frampton
Christopher M
CM
Yandle
Timothy G
TG
Nicholls
M Gary
MG
Richards
A Mark
AM
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D003935:Diagnostic Techniques, Cardiovascular; D004417:Dyspnea / Q000097:blood / Q000209:etiology* / Q000378:metabolism; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood / Q000378:metabolism*; D011863:Radioimmunoassay
D020097:Natriuretic Peptide, Brain