SESSION TYPE: COPD: Diagnosis and Evaluation
PRESENTED ON: Sunday, October 21, 2012 at 01:15 PM - 02:45 PM
PURPOSE: Pulmonary hypertension (PH) is common in patients with severe chronic obstructive pulmonary disease (COPD); however, its prevalence and effects on exercise tolerance and ventilatory efficiency remain unclear. The objectives of the present study were; (i) to determine the effects of PH on exercise capacity and gas exchange in patients with severe COPD and; (ii) to determine the variables that correlate to mean pulmonary artery pressure (mPAP).
METHODS: We retrospectively reviewed 152 patients with severe COPD who were referred to our center. Patients had complete data, including pulmonary function, right heart catheterization and cardiopulmonary exercise testing (CPET) done within 6 months of each other. PH was defined by a resting mPAP > 25 mmHg. Comparisons between COPD patients with and without PH were done by using the t-test and Mann-Whitney U test. Pearson correlation coefficient was used to assess the relationship between continuous variables. Statistical significance was set at p≤0.05.
RESULTS: 98 patients met inclusion criteria. PH was present in 31.6% of patients and most patients were mild (mPAP, 25-35 mmHg). Peak workload (Wattspeak%predicted: PH 15.1±8.5% vs without PH 21.1±15.4%) and oxygen uptake (VO2peak%predicted: PH 30.2±8.6% vs. without PH 36.3±14.6%) on CPET were significantly lower in COPD patients with PH. Mean PAP was found to inversely correlated with six-minute walk distance, VO2peak%predicted, and Wattspeak%predicted. No difference between two groups was seen in any of the ventilatory gas exchange parameters.
CONCLUSIONS: Pulmonary hypertension impairs exercise capacity but doesn’t significantly alter gas exchange in patients with severe COPD.
CLINICAL IMPLICATIONS: There appears to be a relatively high prevalence of PH in severe COPD which causes a decrease in exercise capacity in both CPET and six-minute walk test without changes in ventilatory efficiency. Lower than expected exercise performance in a patient with COPD may indicate a need for evaluation for possible PH.
DISCLOSURE: The following authors have nothing to disclose: Wilawan Thirapatarapong, Hilary Armstrong, Matthew Bartels
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