Study of Incidence of Respiratory Tract AEs in Patients Treated With Tyvaso® Compared to Other FDA Approved PAH Therapies

Inclusion Criteria:

   - Clinical diagnosis of PAH, WHO GROUP I

   - Prescribed and is currently receiving Tyvaso and/or other FDA-approved therapy for the
   treatment of PAH

   - Willing and able to provide written informed consent

Exclusion Criteria:

   - Previous initiation and permanent discontinuation of Tyvaso

   - Participation in an investigational clinical drug or device trial within 30 days of
   enrollment

   - Current or past diagnosis of lung neoplasm

   - Active gastrointestinal or pulmonary bleed at enrollment

   - Planned surgical intervention for treatment of PAH e.g., atrial septostomy or
   transplant