title: Baseline and follow-up 6-min walk distance and brain natriuretic peptide predict 2-year mortality in pulmonary arterial hypertension.
abstract: BACKGROUND
  Six-minute walk distance (6MWD) and brain natriuretic peptide (BNP) levels at baseline and after initiation of treatment have been associated with survival in patients with pulmonary arterial hypertension. Our objective was to determine the individual and additive ability of pretreatment and posttreatment 6MWD and BNP to discriminate 2-year survival in patients with pulmonary arterial hypertension.
  
  
  METHODS
  We included patients enrolled in two randomized clinical trials of ambrisentan who had 2-year follow-up (N 5 370). 6MWD and BNP were assessed before and after 12 weeks of treatment. Receiver operating characteristic curve analyses were performed to identify optimal cutoffs that defi ned subgroups with a high 2-year mortality. Classifi cation and regression tree analysis was used to determine the incremental prognostic value of combined assessments.
  
  
  RESULTS
  6MWD at baseline and after 12 weeks of therapy were similarly discriminatory of 2-year survival (c-statistics 5 0.77 [95% CI 0.70-0.84] and 0.82 [95% CI 0.75-0.88], respectively), whereas change in 6MWD from baseline to week 12 was not discriminating. The same observation was true of BNP at baseline and after 12 weeks of therapy (c-statistics 5 0.68 [95% CI 0.60-0.76] and 0.74 [95% CI 0.66-0.82], respectively). After consideration of baseline 6MWD, there was no prognostic information added by the week 12 6MWD or BNP at either time point.
  
  
  CONCLUSIONS
  6MWD and BNP values at baseline or week 12 identifi ed a population with an elevated risk of death at 2 years. A repeat assessment of 6MWD or BNP after 12 weeks of ambrisentan therapy did not provide additional prognostic information beyond that obtained from baseline values.
authors: Pulmonary, Allergy, and Critical Care Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Medicine, and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors: Jason S
authors: JS
authors: Fritz
authors: Gilead Sciences Inc, Foster City, CA.
authors: Christiana
authors: C
authors: Blair
authors: Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, CA.
authors: Ronald J
authors: RJ
authors: Oudiz
authors: Rubicon Sciences LLC, Nederland, CO.
authors: Christopher
authors: C
authors: Dufton
authors: Department of Internal Medicine, Division of Pulmonology, Medical University of Graz, Graz, Austria.
authors: Horst
authors: H
authors: Olschewski
authors: Gilead Sciences Inc, Foster City, CA.
authors: Darrin
authors: D
authors: Despain
authors: Gilead Sciences Inc, Foster City, CA.
authors: Hunter
authors: H
authors: Gillies
authors: Pulmonary, Allergy, and Critical Care Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Department of Medicine, and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Electronic address: kawut@upenn.edu.
authors: Steven M
authors: SM
authors: Kawut
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D005080:Exercise Test; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy / Q000401:mortality*; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010666:Phenylpropionates / Q000627:therapeutic use; D011237:Predictive Value of Tests; D011379:Prognosis; D011724:Pyridazines / Q000627:therapeutic use; D015996:Survival Rate; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*
chemical_list: D000959:Antihypertensive Agents; D010666:Phenylpropionates; D011724:Pyridazines; D020097:Natriuretic Peptide, Brain; C467894:ambrisentan