title: Brain natriuretic peptide and n-terminal brain natriuretic peptide in the diagnosis of heart failure in patients with acute shortness of breath.
abstract: 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.
authors.affiliation: Department of Medicine, Christchurch School of Medicine, University of Otago, Christchurch, New Zealand. john.lainchbury@chmeds.ac.nz
authors.forename: John G
authors.initials: JG
authors.lastname: Lainchbury
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Campbell
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Frampton
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Yandle
authors.forename: M Gary
authors.initials: MG
authors.lastname: Nicholls
authors.forename: A Mark
authors.initials: AM
authors.lastname: Richards
mesh_terms: 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
chemical_list: D020097:Natriuretic Peptide, Brain