Venous and arterial changes in pulmonary veno-occlusive disease, mitral stenosis and fibrosing mediastinitis

The pathogenesis of pulmonary veno-occlusive disease (PVOD) is not known. The diagnosis of PVOD frequently relies on its histological changes since it is often difficult to distinguish clinically from primary pulmonary hypertension. This study carried out a systematic analysis of the pulmonary venous and arterial remodelling that occurs in PVOD (n=5) and compared these changes to two other diseases affecting the pulmonary veins, mitral stenosis (MS; n=6) and fibrosing mediastinitis (FM; n=2), using established morphometric techniques. In PVOD, pronounced intimal and adventitial thickening were noted in veins of all sizes and arterialization of veins >50 microm external diameter was found. Similar changes were evident in the arterial wall, but intimal thickening was less severe than in the veins and medial thickening was more pronounced in arteries