This is an observational, multicenter, single-day, Phase 2 study. This study will include a 14-day Screening Period and Study Day 1 clinic visit. Participants will be required to perform an activity to induce symptoms of PAH, and participants' severity of self-reported symptoms of PAH will be measured from pre-activity, immediately after the activity, and through the 30-minute recovery. Participants will be asked about their PAH symptoms using 3 Patient Global Impression of Severity (PGI-S) questions that address their overall PAH symptoms, shortness of breath, and physical fatigue.~PAH symptoms will be induced via the Incremental Shuttle Walk Test (ISWT). The ISWT used in this study required the participant to walk back and forth on a 10-meter course. The total number of shuttles completed by a participant during the Screening ISWT will be the maximum targeted for that participant during the remaining ISWTs in the study.~After Screening, participants will be assigned to 1 of 2 cohorts based on PAH medications as prescribed by their physician: Cohort A will include participants who are currently prescribed and using inhaled treprostinil for the treatment of PAH and Cohort B will include participants who are taking other PAH medications (instead of inhaled treprostinil).~The study also includes 2 periods. One period for participants in Cohort A (Treprostinil Users), included an ISWT initiated within 30 minutes of the previous dose (expected peak level) and the other period included an ISWT within 3 to 4 hours of the previous dose of inhaled treprostinil (expected trough level). Participants in Cohort B (Non-Treprostinil Users), an ISWT will be initiated approximately 4 hours after the morning dose of PAH medication (Period 1) and an ISWT initiated at least 1 hour following completion of the previous ISWT (Period 2). Participants will be provided at least a 1-hour period for rest between ISWTs (until participant feels they are rested enough to perform again at their baseline level) prior to Period 2 assessments.
This is an observational, multicenter, single-day, Phase 2 study. This study will include a 14-day Screening Period and Study Day 1 clinic visit. Participants will be required to perform an activity to induce symptoms of PAH, and participants' severity of self-reported symptoms of PAH will be measured from pre-activity, immediately after the activity, and through the 30-minute recovery. Participants will be asked about their PAH symptoms using 3 PGI-S questions that address their overall PAH symptoms, shortness of breath, and physical fatigue.