No | Arterial endothelium | Regions of intimal proliferation | Capillary endothelium | |
Normal | 6 | 0 | 0 | 1 |
IPAH untreated | 8 | 4 | 6 | 8 |
IPAH, epoprostenol and bosentan | 6 | 1 | 2 | 1 |
APAH | 9 | 0 | 1 | 1 |
APAH, pulmonary arterial hypertension associated with congenital heart disease; HLA, human leucocyte antigen; IPAH, idiopathic pulmonary arterial hypertension.