Pulmonary arterial hypertension (PAH) is characterized by progressive obliteration of the pulmonary vascular bed. If untreated, PAH progresses to death from right-heart failure. Median survival is < 2 years following diagnosis. PAH is characterized by vasospasm, intimal fibrosis, thrombosis in situ, proliferation of smooth muscles, and medial hypertrophy; plexogenic arteriopathy is the pathologic hallmark of this disorder.1–
Similar vascular lesions, clinical picture, and natural history are encountered in many other conditions, including collagen vascular diseases, portal hypertension, HIV infection, and exposure to anorectic drugs. The new classification scheme incorporates pulmonary hypertension (PH) associated with these illnesses and primary PH (PPH) as types of PAH.2
Advances in understanding of pathogenesis of PAH, along with cellular and molecular research, have led to the development of newer approaches to treatment for a disease previously considered untreatable.