Efficacy and Tolerability of Subcutaneously Administered Treprostinil Sodium in Patients With Severe (Inoperable) Chronic Thromboembolic Pulmonary Hypertension (CTREPH)

Inclusion Criteria:

Written informed consent has been obtained

Patient should be notified of how their information will be handled and possibly shared with regulatory agencies when needed.

Males or females, ages >18 years, of any racial origin with severe CTEPH with at least 3 months anticoagulation.

Women of child bearing potential are surgically sterile or postmenopausal(amenorrhea for at least 12 months) or on acceptable form of birth control. A double barrier method of birth control, such as a condom and spermicide is mandatory.

An un-encouraged six minute walk (6MWT) test of between 150 and 400 meters

Cardiac catheterization within the past 6 months consistent with PH, specifically PAPm >25 mmHg (at rest), PCWP (or left ventricular end diastolic pressure) <15 mmHg, and PVR >3 mmHg/L/min

Within the past 12 months patients must have had a chest radiograph or an alternative diagnostic imaging consistent with the diagnosis of PH.

Be willing and able to follow all study procedures

Exclusion Criteria:

Have any other form of pulmonary hypertension, pulmonary venous hypertension, peripheral vascular occlusive disease (PVOD) or PCH, or severe chronic obstructive pulmonary disease (COPD).

Be considering pregnancy, be pregnant and/or lactating

Have any acute concomitant disease other than those accepted as part of the inclusion criteria

Have received any prostanoid, within the 30 days before screening or be scheduled to receive any during the course of the study

Have an increased risk for hemorrhage (INR >3)

Have received any investigational medication within 30 days prior to the start of this study or be scheduled to receive another investigational drug during the course of this study

Have a known intolerance to any drug, especially to treprostinil sodium or prostanoids

Have a history or suspicion of inability to cooperate adequately

Have a new type of chronic therapy (e.g., a different category of vasodilator, diuretic) for PAH added within the last month, excepting anticoagulants

Have any preexisting disease known to cause pulmonary hypertension (e.g., obstructive lung disease, parasitic disease affecting the pulmonary system, sickle cell anemia, mitral valve stenosis, portal hypertension)

Have any musculoskeletal disease or any other disease that would limit ambulation.

Have any serious liver problems (Child-Pugh, class C), such as active gastrointestinal ulcer, intrabdominal hemorrhaging.