Safety and Efficacy of Inhaled Iloprost in Pediatric Patients With Pulmonary Arterial Hypertension

Inclusion Criteria: * Male or female, age 3-18 years * Diagnosis of PAH due to IPAH, connective tissue disease, or congenital heart disease * Pulmonary arterial hypertension confirmed by a cardiac catheterization, with mPAP \> 25 mmHg at rest, PCWP or LVEDP ≤ 15 mmHg, and PVR ≥ 240 dynes/sec/cm-5 (ie, ≥ 3.0 units m2) * NYHA/WHO functional Class II, III, or IV * Have had a 6-minute walk test (6-MWT) performed within the 3 months preceding the screening visit (if ≥ 8 years of age) * Have had cardiopulmonary exercise testing (CPET) performed within the 3 months preceding the screening visit (if ≥ 8 years of age and \> 130 cms in height. CPET testing will be conducted on NYHA/WHO Class IV patients at the discretion of the Principal Investigator) * If receiving therapy for PAH, on a stable dose and regimen for at least 3 months prior to the screening visit * If receiving digoxin, diuretic, or oxygen therapy, on a stable dose and regimen for at least 30 days preceding the screening visit * Must demonstrate the ability to appropriately use the nebulizer device as part of the screening process Exclusion Criteria: * Prior use of prostacyclins or prostacyclin analogues within 3 months prior to screening * Portal hypertension or clinically relevant hepatic disease * Eisenmenger syndrome with resting SpO2 \<88% on room air * Clinically relevant asthma or other chronic lung disease, such as bronchopulmonary dysplasia, cystic fibrosis, or repaired or unrepaired congenital diaphragmatic hernia * Diagnosis or current evidence of active lung infection or clinically relevant hemoptysis * Left-sided heart disease, including valvular disease or heart failure * Initiation or dosage adjustment of PAH-specific therapy within 3 months prior to screening * Initiation of treatment with digoxin, diuretics, anticoagulation, or oxygen therapy within 30 days prior to screening