title: NT-proBNP in chronic hypercapnic respiratory failure: a marker of disease severity, treatment effect and prognosis.
abstract: BACKGROUND
  Natriuretic peptides are considered as reliable indicators of left-heart failure (HF) and are useful for differential diagnosis of dyspnoea.
  
  
  OBJECTIVE
  We evaluated the clinical significance of N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with chronic hypercapnic respiratory failure (CHRF).
  
  
  METHODS
  In 60 patients with CHRF, plasma concentrations of NT-proBNP were assessed at baseline and after treatment including non-invasive ventilation (NIV). The relationship of NT-proBNP to disease severity and its predictive value for survival were evaluated up to 4 years.
  
  
  RESULTS
  NT-proBNP levels were markedly elevated in patients with CHRF (n=60; geometric mean (SD) 546.4 (4.9) pg/mL; p<0.001) compared to healthy controls (n=182; 49.0 (2.2) pg/mL). After excluding patients with concomitant HF or renal impairment, levels were still increased (n=43; 393.2 (3.8) pg/mL; p<0.001). According to multivariate regression, hypoxia and exacerbation independently determined NT-proBNP levels (p<0.05 each). After initiation of NIV, blood gases and lung function improved and NT-proBNP decreased (-31.3 (0.3)%; p<0.001). During 22.5 (2.2) months follow-up, NT-proBNP was not significantly associated with survival in the total population, however, the subgroup of patients with levels >722 pg/mL (67th percentile) and no adherence to NIV displayed poor prognosis (hazard ratio=0.21; 95%-CI=0.022-0.580; p=0.0091).
  
  
  CONCLUSIONS
  NT-proBNP was highly elevated in patients with CHRF and correlated with the degree of respiratory impairment and exacerbation. Correspondingly, treatment including NIV led to reduction of NT-proBNP. These data indicate a potential role of NT-proBNP in assessing disease severity, treatment efficacy and prognosis in CHRF.
authors.affiliation: Center for Pneumology, Hospital Donaustauf, Ludwigstrasse 68, D-93093 Donaustauf, Germany. stephan.budweiser@klinik.uni-regensburg.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Budweiser
authors.forename: Andreas
authors.initials: A
authors.lastname: Luchner
authors.forename: Rudolf A
authors.initials: RA
authors.lastname: Jörres
authors.forename: Frank
authors.initials: F
authors.lastname: Heinemann
authors.forename: André P
authors.initials: AP
authors.lastname: Hitzl
authors.forename: Kathrin
authors.initials: K
authors.lastname: Schmidbauer
authors.forename: Günter
authors.initials: G
authors.lastname: Riegger
authors.forename: Michael
authors.initials: M
authors.lastname: Pfeifer
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood / Q000175:diagnosis / Q000628:therapy; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D010446:Peptide Fragments / Q000097:blood*; D011379:Prognosis; D011446:Prospective Studies; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000097:blood / Q000175:diagnosis* / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D002245:Carbon Dioxide; D010100:Oxygen