Table 2

Characteristics of COPD subjects

 COPD subjects with severe PHCOPD subjects without severe PHp Value
Sex ratio
 Smoking status (Y/N)20/020/0
 Current smoker (Y/N)5/157/130.731
 Pack year (no)31 (11–47)31 (25–40)0.978
 FEV1 (% pred)52±2152±210.983
 FEV1/FVC (%)54±1550±150.380
 TLC (%)99 (92–105)107 (94–130)0.182
 RV (%)124 (98–148)134 (102–225)0.579
 TLCO (%)24±1040±220.008
Six-minute walk test
 Distance (m)271±100370±680.003
Arterial blood gases (ambient air)
 PaO2 (mm Hg)51±659±130.014
 PaCO2 (mm Hg)36 (29–41)37 (34–43)0.228
Right heart catheterisation
 mPAP (mm Hg)45±625±5<0.001
 sPAP (mm Hg)70±1439±8<0.001
 dPAP (mm Hg)28±415±4<0.001
 PCWP (mmHg)9±27±30.012
 Gradient (mm Hg)20±49±3<0.001
 PVR (Wood unit)8±24±1<0.001
 PVRi (Wood unit/m2)14±57±1<0.001
 Cardiac output (L/min)5±1.25±1.20.557
 Cardiac index (L/min/m2)3±0.73±0.50.556
 CRP (pg/mL)5±36±20.377
 BNP (mg/mL)481±114177±2150.019
  • Severe PH in COPD is defined mPAP ≥35 mm Hg, without <35 mm Hg. Data are means±SD for continuous normal variables, or median with IQR if their distribution is not normal. Comparisons of continuous variables were made with the t tests or with Mann–Whitney tests for non-parametric variables. Categorical variables were analysed with Fisher's exact tests.

  • BMI, body mass index; BNP, brain natriuretic peptide; CRP, C reactive protein; Gradient, dPAP-PCWP; m, s, dPAP, mean, systolic, diastolic pulmonary arterial pressure; PCWP, pulmonary capillary wedge pressure; PFT, pulmonary function test; PH, pulmonary hypertension; pred, predicted; PVR, pulmonary vascular resistance; PVRi, indexed PVR; RV= residual volume; TLC= total lung capacity; TLCO= transfert lung capacity of carbon monoxide.