Remodulin® (treprostinil sodium), a stable analogue of prostacyclin, possesses potent pulmonary and systemic vasodilatory and platelet anti-aggregatory actions in vitro and in vivo. Recently, Remodulin received FDA approval for intravenous therapy based upon bioequivalence of the intravenous (IV) and subcutaneous (SC) routes of administration. Remodulin is more chemically stable than epoprostenol and may offer potential safety and convenience advantages compared to intravenous epoprostenol that may impact Health Related Quality of Life (HRQOL) and/or patient satisfaction. Unlike epoprostenol, Remodulin does not need to be mixed daily and is stable at room temperature eliminating the need for ice packs. Since Remodulin remains in the body longer than epoprostenol (4 hrs instead of less than 5 minutes) there is less risk of cardiovascular collapse from a sudden interruption of infusion, such as a line clog. In an open-label study in Europe, patients who were using a type of portable medication pump called the CADD Legacy pump were rapidly switched from Flolan to Remodulin with no serious side effects. This study will examine effects of switching from therapy with epoprostenol or Flolan to IV Remodulin and compare changes in HRQOL and treatment satisfaction before and after rapid switch from epoprostenol to Remodulin in patients with pulmonary hypertension from the CADD legacy pump to a smaller pump called the Crono Five.