Table 1

 Mean (SD) baseline characteristics of subjects randomised to receive sildenafil or placebo treatment

Sildenafil 25 mg tds(n = 9)Sildenafil 100 mg tds(n = 5)Placebo(n = 8)
BMI, body mass index; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; Po2, Pco2, oxygen and carbon dioxide tension; Hb, haemoglobin.
Age (years)
    Mean61 (8)60 (8)59 (8)
    Range44–6754–7249–65
Weight (kg)75 (10.6)82 (19.2)70 (10.6)
BMI (kg/m2)30 (4.8)29.5 (4.1)26.1 (5.2)
FEV1 (l)2.4 (0.7)2.5 (1)1.9 (0.7)
FVC (l)2.9 (0.9)3.3 (1.1)2.6 (0.8)
Po2 (kPa)8.6 (0.6)9.1 (1.2)8.4 (1.8)
Pco2 (kPa)4.9 (0.5)4.8 (0.4)5.5 (1.0)
Hb (g/d1)16.4 (2.4)15.7 (1.5)16.3 (1.7)
Haematocrit (%)51 (6.7)48 (5)52 (7.3)
NYHA/WHO functional class(I/II/III)2/2/51/2/21/2/5
6 minute walk (m)420 (85)449 (84)422 (69)