Sustained symptomatic, functional, and hemodynamic benefit with the selective endothelin-A receptor antagonist, sitaxsentan, in patients with pulmonary arterial hypertension: a 1-year follow-up study. - Langleben D; Hirsch AM; Shalit E; Lesenko L; Barst RJ; Langleben, David; Hirsch, Andrew M; Shalit, Eileen; Lesenko, Lyda; Barst, Robyn J (CHEST, 2004)