Study of Intravenous Remodulin in Patients in India With Pulmonary Arterial Hypertension

Inclusion Criteria: Patients Must 1. Between 16- 75 years of age. 2. Male or, if female, physiologically incapable of childbearing or utilizing birth control. 3. Have current diagnosis of symptom-limited NYHA Functional Class III/IV PAH that is: * PPH ("idiopathic" or familial PAH); or * PAH associated with collagen vascular disease (confirmed by antinuclear antibody titer or acceptable test); or * PAH associated with HIV infection (confirmed by serological test). 4. If HIV positive, have CD4 lymphocyte count ≥ 200 at baseline and receiving current SOC anti-retroviral or effective medication for HIV infection. 5. Optimally treated with conventional PH therapy and clinically stable for at least 1 month prior to baseline. 6. Have ventilation/perfusion scan, contrast-enhanced CT scan, or pulmonary angiogram after onset of PAH that rules out pulmonary embolism. 7. Have cardiac catheterization in last 3 months (or at Baseline) showing: * PAPm \> 35 mmHg (at rest) \& * PCWPm (or LV end diastolic pressure) \< 16 mmHg \& * PVR \> 5 mmHg/L/min. 8. Have echocardiogram in last 3 months consistent with PH, specifically: * evidence of RV hypertrophy or dilation \& * evidence of normal LV function \& * absence of mitral valve stenosis. 9. Have chest radiograph consistent with PH performed in last 3 months. Radiograph must show clear lung fields or no more than patchy interstitial infiltrates. 10. Unless contraindicated, able to receive one of following anticoagulants: warfarin to achieve INR between 1.5-2.5 or heparin to produce aPTT between 1.3-1.5 times control, unless higher levels clinically indicated. 11. Mentally and physically capable of learning to administer Study Drug using ambulatory intravenous infusion pump and central venous access, or have trained caregiver. 12. If on corticosteroids, receiving stable dose of 20 mg/day of prednisone (or equivalent dose of another steroid) for at least 1 month prior to entry. Exclusion Criteria: Patients must not: 1. Nursing or pregnant (women of childbearing potential have negative pregnancy test). 2. Have had new type of chronic therapy (including but not limited to oxygen, different category of vasodilator, diuretic, digoxin) for PH, except for anticoagulants, added in last month. 3. Be scheduled for heart-lung transplant. 4. Have any PH medication except for anticoagulants discontinued in week prior to study entry. 5. Have received any chronic prostaglandin or prostaglandin analogue (including intravenous/inhaled/oral: epoprostenol, iloprost, beraprost, etc.), any phosphodiesterase inhibitor therapy such as sildenafil, or any endothelin antagonist therapy such as bosentan, in past 30 days. 6. Have PH associated with chronic thromboembolic disease; or chronic obstructive lung diseases or hypoxemia; or evidence of significant parenchymal lung disease as evidenced by PFTs in last 3 months as follows (any one of following): * TLC \< 60% (predicted) or high resolution CT documenting diffuse interstitial fibrosis or alveolitis * FEV1/FVC ratio \< 50% 7. Have Portal Hypertension. 8. Have history of uncontrolled Sleep Apnea, defined as oxygen desaturation less than 90% at night, in past 3 months. 9. Have history of left-sided heart disease including: * Aortic or mitral valve disease or * Pericardial constriction or * Restrictive or congestive cardiomyopathy; or have evidence of current left-sided heart disease defined by: * PCWPm or LV end diastolic pressure \> 16 mmHg or * LVEF \< 40% by MUGA, angiography or echocardiography or * LV Shortening Fraction \< 22% by echocardiography or * Symptomatic coronary disease (demonstrable ischemia). 10. Have any disease other than HIV or connective tissue disease associated with PH (e.g. sickle cell anemia, schistosomiasis). 11. Have active AIDS or tuberculosis. 12. Have musculoskeletal disorder (e.g. arthritis, artificial leg, etc.) or any other disease thought to limit ambulation, or connected to machine which is not portable. 13. Have baseline exercise capacity of \<50 m or \>325 m as measured by 6-Minute Walk Test. 14. Have uncontrolled systemic hypertension as evidenced by systolic blood pressure \>160 mmHg or diastolic blood pressure \>100 mmHg. 15. Have used prescription appetite suppressants in 3 months of study entry. 16. Have chronic renal insufficiency defined by creatinine \>2.5 mg/dL or requiring dialysis. 17. Receiving an investigational drug (other than acute challenge with epoprostenol), have in place an investigational device, or have participated in investigational drug/device study in past 30 days. 18. Have presence of any physiological or mental condition which contraindicates administration of Remodulin.