title: Directing therapy in pulmonary arterial hypertension using a target 6 min walk distance.
abstract: BACKGROUND
  The most effective approaches to escalating advanced therapies in pulmonary arterial hypertension (PAH) are controversial.
  
  
  OBJECTIVE
  To compare outcomes before and after introducing a target 6 min walk distance (6MWD) treatment strategy in PAH using registry data.
  
  
  METHODS
  From 2001 to 2005, WHO class II to IV patients were treated with bosentan or prostanoids. In July 2005, a target 6MWD strategy was adopted. Monotherapy continued if 6MWD remained >350 m. For patients in whom 6MWD was ≤350 m, sildenafil was added. If 6MWD remained <350 m, prostanoids were considered. Changes in 6MWD, WHO class and survival rate were compared between periods.
  
  
  RESULTS
  Before using the 6MWD strategy, there was a statistically significant improvement in mean WHO class at six, nine and 12 months (2.5±0.8 [P<0.015]; 2.5±0.8 [P<0.005]; and 2.5±0.9 [P<0.03], respectively) compared with baseline (2.9±0.9). There was a statistically significant increase in mean 6MWD at three, six, nine and 12 months (383±113 m [P<0.005]; 401±102 m [P<0.006]; 400±109 m [P<0.001]; and 399±110 m [P<0.004], respectively) compared with baseline (321±119 m). The survival rate was 95% at one and two years. From 2005 to 2009, there was a statistically significant improvement in mean WHO class at three, six, nine and 12 months (2.6±0.8 [P<0.05]; 2.3±0.9 [P<0.0001]; 2.3±0.9 [P<0.0001]; and 2.3±1.0 [P<0.0005], respectively) compared with baseline (2.8±0.7). There was statistically significant improvement in 6MWD at six months (381±126 m [P<0.05]), followed by a decline toward baseline (354±117 m). One- and two-year survival rates in the 6MWD target era were 95% and 80%, respectively.
  
  
  CONCLUSIONS
  Based on registry data, adoption of this strategy did not affect survival rates, nor cause a sustained improvement in 6MWD by 12 months. WHO class improved similarly in both treatment groups.
authors.affiliation: Section of Respiratory Medicine, University of Manitoba, Winnipeg. nporhownik@hsc.mb.ca
authors.forename: Nancy Rose
authors.initials: NR
authors.lastname: Porhownik
authors.forename: Renelle
authors.initials: R
authors.lastname: Myers
authors.forename: Zoheir
authors.initials: Z
authors.lastname: Bshouty
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D000077300:Bosentan; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005080:Exercise Test; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000401:mortality; D016285:Iloprost / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010347:Patient Care Planning; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D012042:Registries; D012720:Severity of Illness Index; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000627:therapeutic use*; D013450:Sulfones / Q000627:therapeutic use*; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D000959:Antihypertensive Agents; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate; D016285:Iloprost; D000077300:Bosentan