title: High plasma brain natriuretic peptide levels in stable COPD without pulmonary hypertension or cor pulmonale.
abstract: BACKGROUND
  Early diagnosis of chronic obstructive pulmonary disease (COPD) with latent pulmonary hypertension (PH) and cor pulmonale is important because the prognosis of this condition is poor.
  
  
  OBJECTIVE
  To investigate the utility of brain natriuretic peptide (BNP) for prognostication of COPD, plasma BNP was measured in patients with COPD without symptoms or physical findings of PH or cor pulmonale.
  
  
  METHODS
  Plasma BNP was measured in 60 patients with COPD, 10 asthmatics, and 30 healthy subjects. Echocardiography, arterial blood gas analysis, and spirometry were also performed. Mortality and exacerbation were compared between COPD patients with high and low plasma BNP levels over a 3-year follow-up period.
  
  
  RESULTS
  Plasma BNP (mean +/- SEM, pg/mL) in COPD patients (41.0+/-6.6) was significantly higher than in normal subjects (14.8+/-2.7) and asthmatics (17.4+/-4.5) (p<0.0001 and p<0.05, respectively). No significant correlations were observed between plasma BNP level and pulmonary function or hypoxia. There was, however, a significant correlation between plasma BNP level and % ejection fraction (r=-0.41, p=0.0197) and pulmonary artery systolic pressure (r=0.5, p=0.004). The period until initial COPD exacerbation in subjects with a high plasma BNP level was significantly shorter (p<0.05). Plasma BNP level during exacerbations (79.9+/-16.2) was also significantly higher than during stable disease (41.2+/-8.7) (p=0.004).
  
  
  CONCLUSIONS
  We suggest that plasma BNP is a non-invasive biomarker that can be used as a screening parameter for latent PH and left ventricular dysfunction, and also as a predictor of exacerbation in stable COPD.
authors.affiliation: Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Inoue
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Kawayama
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Iwanaga
authors.forename: Hisamichi
authors.initials: H
authors.lastname: Aizawa