The present study aimed to explore the prevalence of pre-capillary pulmonary hypertension (PH) and characterize hemodynamic vascular responses to physical exercise in COPD outpatients, where LV dysfunction and co-morbidities were excluded.
Ninety-eight patients with COPD underwent right heart catheterization at rest and during supine exercise. Mean pulmonary artery pressure (mP(pa)), pulmonary wedge pressure (Ppaw) and cardiac output (CO) were measured at rest and during exercise. Exercise induced increase in mP(pa) was interpreted relative to increase in blood flow, mP(pa)/CO, and workload, mP(pa)/W. Pulmonary vascular resistance (PVR) and pulmonary artery compliance (PAC) were calculated.
PH was defined as mP(pa)-rest≥25 and Ppaw-rest<15 mmHg.Prevalence of PH was 5, 27 and 53 % in GOLD stages II, III and IV, respectively. The absolute exercise induced rise in mP(pa) did not differ between PH and no-PH. Patients without PH showed similar abnormal hemodynamic responses to exercise as the PH group, with increased PVR, reduced PAC and steeper slopes for mP(pa)/CO and mP(pa)/W.
Exercise revealed abnormal physiologic hemodynamic responses in the majority of the COPD patients. The future definition of PH on exercise in COPD should rely on the slope of mP(pa) related to CO or workload rather than the absolute values of mP(pa).
Authors: Mykland Hilde J, Skjørten I, Hansteen V, Nissen Melsom M, Hisdal J, Humerfelt S, Steine K
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