Primary end-point events in the placebo and bosentan groups
| Placebo | Bosentan | |
| Patients n | 175 | 159 |
| Primary end-point event | 90 (51.4) | 68 (42.8) |
| Worsening of PAH# | 52 (29.7) | 32 (20.1) |
| Hospitalisation for PAH or start of i.v. prostanoid therapy | 20 (11.4) | 25 (15.7) |
| Death | 18 (10.3) | 10 (6.3) |
| Atrial septostomy | 0 (0.0) | 1 (0.6) |
| Lung transplantation | 0 (0.0) | 0 (0.0) |
Data are presented as n (%) unless otherwise stated. Events listed are the first confirmed morbidity/mortality events. PAH: pulmonary arterial hypertension. #: worsening PAH was 1) “moderately worse” or “markedly worse” symptoms and requirement for addition of PAH therapy (initiation of a subcutaneous or inhaled prostanoid, or transfer to open-label bosentan), or 2) “no change” or “mildly worse” symptoms, and requirement for addition of PAH therapy and deterioration in 6-min walk distance >20% from the previous visit or >30% from the baseline visit.