title: The prognostic relevance of oxygen uptake in inoperable chronic thromboembolic pulmonary hypertension.
abstract: BACKGROUND
  Patients with chronic thromboembolic pulmonary hypertension (CTEPH) present with a decreased oxygen uptake, however, the prognostic relevance of oxygen uptake (VO2) in inoperable CTEPH is unknown.
  
  
  METHODS
  Patients with inoperable CTEPH were retrospectively analyzed. All patients were assessed by means of right heart catheterisation and cardio pulmonary exercise testing in semisupine position with a 30 Watt increment step-protocol.
  
  
  RESULTS
  One-hundred and fifty-one patients (82 female (54.3%), mean age 61 ± 12.4 years) presented with a mean pulmonary arterial pressure of 40.2 ± 14.2 mmHg and pulmonary vascular resistance (PVR) of 641.9 ± 374.8 dyne∗s/cm5. The peak VO2(mean 13.1 ± 4.5 mL∗kg-1∗min-1) was measured at initial referral. Over a follow-up of up to 10 years (mean 4.41 ± 2.57 years), 31 patients had died. Patients with a baseline peak VO2≥ 10.7 mL∗kg-1∗min-1[area under the receiver-operating characteristic curve (AUC) = 0.728, P = 0.001] had better survival than those with a peak VO2≤ 10.7 mL∗kg-1∗min-1using Kaplan-Meier analysis (88.8% vs 60.1%; log rank P = 0.001). Adjusting for age, gender and PVR, multivariate analysis identified peak VO2as a predictor of mortality [hazard ratio (HR): 2.78, 95% CI 1.01-7.63, P = 0.047]. In addition, peak VO2failed as an independent prognostic factor in a stepwise multivariate model including all variables significant in the univariate analysis.
  
  
  CONCLUSIONS
  In patients with inoperable CTEPH the peak VO2is a significant predictor of survival, when adjusting for age, gender and PVR. However, peak VO2failed as an independent prognostic factor when correcting for all significant baseline variables, which is limiting the clinical usability.
authors.affiliation: Department of Pneumology, Kerckhoff Heart, Rheuma and Thoracic Center, Bad Nauheim, Germany.|Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).
authors.forename: Manuel Jonas
authors.initials: MJ
authors.lastname: Richter
authors.affiliation: Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).
authors.forename: Philip
authors.initials: P
authors.lastname: Pader
authors.affiliation: Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).
authors.forename: Henning
authors.initials: H
authors.lastname: Gall
authors.affiliation: Department of Pneumology, Asklepios Hospital, Munich-Gauting, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Reichenberger
authors.affiliation: Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).
authors.forename: Werner
authors.initials: W
authors.lastname: Seeger
authors.affiliation: Department of Thoracic Surgery, Kerckhoff Heart, Rheuma and Thoracic Center, Bad Nauheim, Germany.
authors.forename: Eckhard
authors.initials: E
authors.lastname: Mayer
authors.affiliation: Department of Thoracic Surgery, Kerckhoff Heart, Rheuma and Thoracic Center, Bad Nauheim, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Guth
authors.affiliation: Department of Thoracic Surgery, Kerckhoff Heart, Rheuma and Thoracic Center, Bad Nauheim, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Kramm
authors.affiliation: Department of Pneumology, Kerckhoff Heart, Rheuma and Thoracic Center, Bad Nauheim, Germany.|Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).
authors.forename: Friedrich
authors.initials: F
authors.lastname: Grimminger
authors.affiliation: Department of Pneumology, Kerckhoff Heart, Rheuma and Thoracic Center, Bad Nauheim, Germany.|Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).
authors.forename: Hossein A
authors.initials: HA
authors.lastname: Ghofrani
authors.affiliation: Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL).|Department of Internal Medicine, Health Center Wetterau, Friedberg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Voswinckel
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization / Q000379:methods; D002908:Chronic Disease; D004452:Echocardiography / Q000379:methods; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D011379:Prognosis; D011651:Pulmonary Artery / Q000502:physiology; D011655:Pulmonary Embolism / Q000378:metabolism*; D012189:Retrospective Studies; D016019:Survival Analysis; D014655:Vascular Resistance / Q000502:physiology
chemical_list: D010100:Oxygen
keywords: cardio pulmonary exercise testing - chronic thromboembolic pulmonary hypertension - oxygen uptake - prognostic factor - survival