title: Oxygen desaturation on the six-minute walk test and mortality in untreated primary pulmonary hypertension.
abstract: There are no reliable predictors of mortality in primary pulmonary hypertension (PPH). This study assessed whether exercise oxygen desaturation and distance achieved during a six-minute walk are associated with mortality in moderately symptomatic patients with PPH. Thirty-four patients with PPH underwent a pretreatment six-minute walk test, and an invasive haemodynamic assessment of pulmonary vasodilator reserve, to select the best treatment option (epoprostenol in 27 and nifedipine in 7). Median follow-up was 26 months (12 months for the nonsurvivors was 26%), and median survival, >46 months by Kaplan-Maier estimate. The mean+/-SD distance walked was 275+/-155 m and reduction in arterial oxygen saturation (Sa,O2) at maximal distance (deltaSa,O2) was 8.4+/-4.5%). A distance < or =300 m increased mortality risk by 2.4, and a deltaSa,O2 of > or = 10% increased mortality risk by 2.9. Only Sa,O2 at peak distance, deltaSa,O2 and pulmonary vascular resistance (PVR) were related to mortality. After adjusting for PVR, there remained a 27% increase in risk of death for each per cent decrease in Sa,O2. The six-minute walk distance and exercise oxygen saturation may be helpful in selecting patients with primary pulmonary hypertension for whom transplant listing is appropriate.
authors.affiliation: Dept of Internal Medicine, University of Michigan, Ann Arbor, USA.
authors.forename: G
authors.initials: G
authors.lastname: Paciocco
authors.forename: F J
authors.initials: FJ
authors.lastname: Martinez
authors.forename: E
authors.initials: E
authors.lastname: Bossone
authors.forename: E
authors.initials: E
authors.lastname: Pielsticker
authors.forename: B
authors.initials: B
authors.lastname: Gillespie
authors.forename: M
authors.initials: M
authors.lastname: Rubenfire
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D011464:Epoprostenol / Q000627:therapeutic use; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy / Q000401:mortality* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000627:therapeutic use; D010100:Oxygen / Q000097:blood*; D011652:Pulmonary Circulation; D015996:Survival Rate; D014655:Vascular Resistance; D014665:Vasodilator Agents / Q000627:therapeutic use; D016138:Walking
chemical_list: D000959:Antihypertensive Agents; D014665:Vasodilator Agents; D011464:Epoprostenol; D009543:Nifedipine; D010100:Oxygen