Terence K. Trow, MD

Abstract: Our understanding of the pathobiology of pulmonary arterial hypertension (PAH) has evolved considerably over the past 2 decades, with increasing recognition of the important role that aberrant vasoproliferative responses play in conjunction with disordered vasoconstriction. Classification of the many forms of PAH into categories sharing a similar pathophysiology and clinical presentations help the practicing clinician approach a complex differential diagnosis. Noninvasive tests can be used to narrow this differential but must be applied with an appreciation for their limitations. Transthoracic echocardiography is the screening tool of choice; the workup should also include chest radiography and electrocardiography. However, right heart catheterization is ultimately required to establish the diagnosis. While PAH remains a progressive and generally fatal disease, existing therapies have a significant impact on survival and new therapeutic targets offer great hope for improving the prognosis. (J Respir Dis. 2006;27(11):487-493)