ADAPT - A Patient Registry of the Real-world Use of Orenitram®

INCLUSION CRITERIA Patients are eligible for the registry if: 1. The patient voluntarily gives informed consent to participate in the study. 2. The patient must be at least 18 years of age or older. 3. The patient is prescribed Orenitram (per the package insert indication), and plans to initiate therapy with this medication or has been receiving Orenitram for 182 or fewer days. 4. The patient agrees to dosing, prostacyclin-related AE of interest record keeping, survey participation during designated time periods, and recording any medication changes, use, for the duration of the study. 5. The patient has the ability to answer surveys and use the diary in English. 6. The patient must have an email address and be willing to access the PRO Portal. EXCLUSION CRITERIA Patients are ineligible for the registry if: 1. The patient has previously received Orenitram for more than 182 days. 2. The patient is currently participating in an investigational drug or device study or has participated in a clinical study with an investigational product other than Orenitram in PAH within