Seminars in respiratory and critical care medicine
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Semin Respir Crit Care Med · Aug 2009
Definition, classification, and epidemiology of pulmonary arterial hypertension.
Pulmonary arterial hypertension (PAH) is a distinct subgroup of pulmonary hypertension that comprises idiopathic PAH, familial/heritable forms, and PAH associated with connective tissue disease, congenital heart disease, portal hypertension, human immunodeficiency virus (HIV) infection, and some other conditions. The hemodynamic definition of PAH was recently revised: PAH is now defined by a mean pulmonary artery pressure at rest > or =25 mm Hg in the presence of a pulmonary capillary wedge pressure < or =15 mm Hg. ⋯ The revised classification of pulmonary hypertension still consists of five major groups: (1) PAH, (2) pulmonary hypertension due to left heart disease, (3) pulmonary hypertension due to chronic lung disease and/or hypoxia, (4) chronic thromboembolic pulmonary hypertension, and (5) miscellaneous forms. Modifications have been made in some of these groups, such as the addition of schistosomiasis-related pulmonary hypertension and pulmonary hypertension in patients with chronic hemolytic anemia to group 1.