ABSTRACT

Vascular lesions found in lungs of patients suffering from pulmonary hypertension (PH) are classically considered as responsible for the increase of pulmonary arterial pressures and share some characteristic peculiarities, but should not be regarded as specific or even pathognomonic. These fibrotic and proliferative lesions concern the small lung vessels; arterial lesions are typically located in muscular arteries of less than 500 mm diameter in patients with pulmonary arterial hypertension (PAH), while septal veins and preseptal venules are affected in patients with pulmonary veno-occlusive disease (PVOD). And finally the exceptional entity known as pulmonary capillary hemangiomatosis (PCH) concerns alveolar septal capillaries within the lung parenchyma. Previously integrated into the group 1 of PH during the consensus meeting in Venice in 2003, the latter two entities were assigned to a novel category of pulmonary venous hypertension (group 10) after the World Symposium in Dana Point, California, in 2008 (1) (Ge´rald Simonneau, personal communication).