Background: The non-invasive assessment of pulmonary haemodynamics during exercise provides complementary data for the evaluation of exercise tolerance in patients with COPD.
Methods: Exercise echocardiography in the semi-supine position was performed in 27 patients with COPD (C) with a forced expiratory volume in one second (FEV1) of 36±12% predicted and 13 age and gender-matched non-COPD subjects (NC). COPD patients also underwent cardiopulmonary exercise testing with gas exchange detection (CPET). Furthermore, serum high sensitive C-reactive protein (hsCRP), a marker of systemic inflammation, was also measured.
Results: The maximal work rate (WRmax) and aerobic capacity (VO2peak) were significantly reduced (WRmax: 77±33 Watt, VO2peak: 50±14 %pred) in COPD. Pulmonary arterial systolic pressure (PAPs) was higher in COPD versus controls both at rest (39±5 vs. 31±2 mmHg, p<0.001), and at peak exercise (72±12 vs. 52±8 mmHg, p<0.001). In 19 (70%) COPD patients, the increase in PAPs was above 22 mmHg. The change in pressure (dPAPs) correlated with hsCRP (r2=0.53, p<0.0001) and forced vital capacity (FVC) (r2=0.18, p<0.001).
Conclusion: PAPs at rest and during exercise were significantly higher in COPD patients and correlated with higher hsCRP. This may indicate a role for systemic inflammation and hyperinflation in the pulmonary vasculature in COPD. The study was registered at ClinicalTrials.gov webpage with NCT00949195 registration number.
Keywords: Chronic obstructive pulmonary disease; Exercise; HS-CRP; Pulmonary hypertension; Systemic inflammation.