TABLE 1

Baseline characteristics of the study population

CharacteristicMPAP ≥21 mmHgMPAP <21 mmHgp-value
Subjects#55218
Age years64.5±6.866.7±7.80.06
Male44 (80.0)183 (83.9)0.49
BMI kg·m−224.7±4.023.6±3.20.05
pack-years43.1±37.434.7±33.50.10
mMRC dyspnoea scale<0.001
 Level 0772
 Level 12196
 Level 21437
 Level 31011
 Level 432
PaO2 mmHg74.5±12.183.5±11.3<0.001
BNP pg·mL−120.7 (10.8–34.9)17.2 (9.7–30.9)0.23
FVC % predicted75.4±20.882±19.20.03
FEV1 % predicted85.4±20.094.3±19.90.003
FEV1/FVC85.7±8.885.1±7.80.60
DLCO % predicted46.9±18.364.3±20.9<0.001
6MWD m508±124585±135<0.001
Lowest SpO2 %77.5±10.584.3±8.2<0.001
HRCT findings
 PA mm28.7±3.626.6±3.8<0.001
 Ao mm32.6±3.633.4±3.60.11
 PA/Ao0.89±0.120.80±0.11<0.001
 Fibrosis %35.0 (24.2–46.7)31.7 (22.5–41.7)0.11
 LAA %1.7 (0.0–11.7)0.0 (0.0–3.3)0.02
 ≥10% in upper zone22 (40.0)54 (24.8)0.02
 ≥25% in upper zone8 (14.5)12 (5.5)0.03
Echocardiograph findings
 Ejection fraction %0.65±0.120.68±0.060.14
 E/A0.47±0.430.65±0.980.18
 Estimated RVSP mmHg29.6±20.622.8±16.40.01
RHC findings
 MPAP mmHg24.9±5.315.0±2.9<0.001
 PVR Wood units3.0±1.81.7±0.7<0.001
 Cardiac index L·min1·m23.0±0.63.0±0.50.96
 PAWP mmHg10.7±3.46.6±3.0<0.001

Data are presented as n, n (%), mean±sd or median (interquartile range), unless otherwise indicated. #: the total number of subjects (N) was 273. MPAP: mean pulmonary arterial pressure; BMI: body mass index; mMRC: modified Medical Research Council; PaO2: arterial oxygen tension; BNP: brain natriuretic peptide; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; DLCO: diffusing capacity of the lung for carbon monoxide; 6MWD: 6-min walk distance; SpO2: arterial oxygen saturation measured by pulse oximetry; HRCT: high-resolution computed tomography; PA: pulmonary artery diameter; Ao: ascending aorta diameter; LAA: low attenuation area; E: peak velocity flow in early diastole (E-wave); A: peak velocity flow in late diastole (A-wave); RVSP: right-ventricular systolic pressure; RHC: right heart catheterisation; PVR: pulmonary vascular resistance; PAWP: pulmonary arterial wedge pressure.