title: Comparing cardiopulmonary exercise testing in severe COPD patients with and without pulmonary hypertension.
abstract: OBJECTIVE
  To determine; (i) the effect of PH on exercise capacity, gas exchange and oxygen pulse; (ii) the variables that correlate with mean pulmonary artery pressure (mPAP) in severe COPD patients.
  
  
  METHODS
  We reviewed 98 severe COPD patients who had pulmonary function, right heart catheterisation, and cardiopulmonary exercise testing (CPET) performed within six months of each other. PH was defined by a resting mPAP > 25 mmHg. COPD patients with and without PH were compared using the independent samples t-test and Mann-Whitney U test. Pearson correlation coefficients were used to assess the relationship between continuous variables.
  
  
  RESULTS
  PH was present in 32% of patients and the majority of PH was mild (mPAP, 25-35 mmHg). Peak workload, oxygen uptake and oxygen pulse on CPET were significantly lower in the PH group. Mean PAP was found to inversely correlate with peak oxygen uptake, with a tendency towards lower six-minute walk distance. No difference between two groups was seen in any of the gas exchange variables.
  
  
  CONCLUSIONS
  In severe COPD, there is a relatively high percentage of PH which causes a decrease in exercise capacity and oxygen pulse without significantly altered ventilation as measured by CPET. Lower than expected exercise performance without a change in pulmonary function may indicate a need for evaluation for possible PH.
authors.affiliation: Department of Rehabilitation Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 Thailand; Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, NY, NY 10032 USA. Electronic address: wilawan.thi@mahidol.ac.th.
authors.forename: Wilawan
authors.initials: W
authors.lastname: Thirapatarapong
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, NY, NY 10032 USA. Electronic address: hfa2104@columbia.edu.
authors.forename: Hilary F
authors.initials: HF
authors.lastname: Armstrong
authors.affiliation: Department of Rehabilitation Medicine, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY 10467 USA. Electronic address: mbartels@montefiore.org.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Bartels
mesh_terms: D062186:Arterial Pressure; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology; D011659:Pulmonary Gas Exchange; D011669:Pulmonary Wedge Pressure; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016138:Walking / Q000502:physiology
chemical_list: D010100:Oxygen
keywords: COPD; Cardiopulmonary exercise testing; Exercise capacity; Gas exchange; Pulmonary hypertension