Wilawan Thirapatarapong1, Hilary F Armstrong2, Matthew N Bartels3. 1. 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. 2. Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, NY, NY 10032 USA. Electronic address: hfa2104@columbia.edu. 3. Department of Rehabilitation Medicine, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY 10467 USA. Electronic address: mbartels@montefiore.org.
Abstract
PURPOSE: 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. CONCLUSION: 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.
PURPOSE: 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 COPDpatients. METHODS: We reviewed 98 severe COPDpatients 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. COPDpatients 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. CONCLUSION: 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.