Rapid Switch From Intravenous Epoprostenol to Intravenous Remodulin® (Treprostinil Sodium) Using the Crono Five Ambulatory Infusion Pump in Patients With Stable Pulmonary Arterial Hypertension (PAH): Safety, Efficacy and Treatment Satisfaction

Study start date: February 1, 2007

Inclusion Criteria: * Age 18 to 65 years * Diagnosis of one of the following WHO Classifications of pulmonary hypertension: 1. Group 1 pulmonary arterial hypertension * Idiopathic pulmonary arterial hypertension (IPAH) * Familial pulmonary arterial hypertension (FPAH) * Associated pulmonary arterial hypertension (APAH): 1. collagen vascular disease 2. congenital systemic-to-pulmonary shunt repaired greater than 5 years prior to study entry. 3. portal hypertension 4. drugs and toxins 2. Group 4 pulmonary hypertension due to chronic thromboembolic pulmonary hypertension (CTEPH) * WHO Class II-III * Currently receiving intravenous epoprostenol therapy for at least three months and a stable dose for at least one month. * Have central intravenous catheter * Optimally treated with conventional pulmonary hypertension therapy and clinically stable for at least one month. * Mentally and physically capable of learning to administer Remodulin using an intravenous infusion pump. Exclusion Criteria: * nursing or pregnant woman * received a new type of chronic therapy (including but not limited to oxygen, a different category of vasodilator, a diuretic, digoxin, bosentan, sildenafil) for pulmonary hypertension added within the last month. * Had any PAH medication discontinued within the week prior to study entry. * Received any prostacyclin or prostacyclin analog except epoprostenol in the past 3 months. * Had a central venous line infection within the past 30 days. * Previous documented evidence of significant parenchymal lung disease as evidenced by pulmonary function tests as follows (any one of the following): 1. Total Lung Capacity ≤ 60% (predicted) or 2. If Total Lung Capacity is between 60% and 70% (predicted), a High Resolution Computed Tomography (CT) scan must be performed to rule out diffuse interstitial fibrosis or alveolitis * History of or evidence of left-sided heart disease * Having any other disease that is associated with pulmonary hypertension (e.g. sickle cell anemia, schistosomiasis). * Having a musculoskeletal disorder (e.g. arthritis, artificial leg, etc.) or any other disease, which is thought to limit ambulation, or be connected to a machine, which is not portable. * Uncontrolled systemic hypertension as evidenced by a systolic blood pressure greater than 160 millimeters of mercury (mmHg) or diastolic blood pressure greater than 100 mmHg. * Chronic renal insufficiency as defined by serum creatinine greater than 2.5 milligrams per deciliter (mg/dL) or the requirement for dialysis. * Receiving an investigational drug, have in place an investigational device, or have participated in an investigational drug study within the past 30 days. * Active infection, or any other ongoing condition that would interfere with the interpretation of study assessments. * The presence of any physiological or psychological condition that contraindicates the administration of Remodulin.