Amino-terminal pro-brain natriuretic peptide for the diagnosis of acute heart failure in patients with previous obstructive airway disease.
OBJECTIVE
We evaluate results from amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing with or without those of clinical judgment for the evaluation of dyspneic patients with previous chronic obstructive pulmonary disease or asthma.


METHODS
As a secondary analysis of previously collected observational data from a convenience sample of 599 breathless patients, 216 patients with previous chronic obstructive pulmonary disease or asthma who presented to the emergency department were analyzed according to results of NT-proBNP, clinical impression, and their final diagnosis. Test performance of NT-proBNP in these patients with chronic obstructive pulmonary disease or asthma was examined for the group as a whole, as well as in patients with and without previous heart failure. NT-proBNP results were compared to clinician-estimated likelihood for heart failure using receiver operating curves and as a function of NT-proBNP plus clinical evaluation. The final diagnosis was determined by 2 independent cardiologists blinded to NT-proBNP using all available data from the 60-day follow-up period.


RESULTS
Overall, 55 patients (25%) had acute heart failure; the median value of NT-proBNP was higher in these patients compared with those without acute heart failure (2,238 vs 178 pg/mL); use of cut points of 450 pg/mL for patients younger than 50 years and 900 pg/mL for patients 50 years or older yielded a sensitivity of 87% (95% confidence interval [CI] 72% to 93%) and a specificity of 84% (95% CI 76% to 88%). In patients without previous heart failure (n=164), median NT-proBNP levels were also higher in patients with heart failure of new onset compared with those with chronic obstructive pulmonary disease or asthma exacerbation (1561 versus 168 pg/mL). High clinical suspicion for acute heart failure (probability >80%) detected only 23% of patients with new-onset heart failure, whereas 82% of these patients had elevated NT-proBNP levels. In patients who had both previous acute heart failure and chronic obstructive pulmonary disease or asthma (n=52), median NT-proBNP levels were significantly higher in those with acute heart failure (4,435 pg/mL) than patients with chronic obstructive pulmonary disease or asthma exacerbation (536 pg/mL). In patients with acute-on-chronic heart failure, NT-proBNP levels were elevated in 91%, whereas clinical impression considered only 39% of cases as high likelihood for acute heart failure.


CONCLUSIONS
NT-proBNP may be a useful adjunct to standard clinical evaluation of dyspneic patients with previous obstructive airway disease.
Tung
Roderick H
RH
Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
Camargo
Carlos A
CA
Krauser
Dan
D
Anwaruddin
Saif
S
Baggish
Aaron
A
Chen
Annabel
A
Januzzi
James L
JL
D000208:Acute Disease; D000368:Aged; D001249:Asthma / Q000097:blood* / Q000150:complications; D015415:Biomarkers / Q000097:blood; D003937:Diagnosis, Differential; D004417:Dyspnea / Q000209:etiology; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000150:complications; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain