The participant has a diagnosis of either pulmonary arterial hypertension (PAH) or pulmonary hypertension (PH) due to reasons other than COPD.The following will exclude participants from the study: In the opinion of the Investigator, the participant can communicate effectively with study personnel and is considered reliable, willing, and likely to be cooperative with protocol requirements, including attending all study visits.Participants must be on a stable and optimized dose of chronic COPD medications for greater than or equal to 30 days prior to start of Screening Visit 1 and remain on the same dose throughout the Screening Period.A Pulmonary artery pressure mean (PAPm) of greater than or equal to 30 mmHg.A pulmonary artery wedge pressure (PAWP) or left ventricular end-diastolic pressure (LVEDP) of less than or equal to 15 millimeters of mercury (mmHg).Pulmonary vascular resistance (PVR) greater than or equal to 4 Wood units.(A previous RHC obtained within 12 months prior to the start of Screening Visit 1 is acceptable for determining eligibility, even if done without oxygen or vasodilator challenge, and a repeat RHC is not required.) The following parameters must be documented for eligibility: Have a right heart catheterization (RHC) performed during Screening Visit 1. During Screening Visit 1 prior to start of low-dose inhaled treprostinil, a 6MWD greater than or equal to 100 meters.The participant has a resting saturation peripheral capillary oxygenation (SpO2) greater than or equal to 90%, with or without supplemental oxygen, but not to exceed 10 liters (L)/min oxygen supplementation by any mode of delivery during Screening Visit 1.Forced expiratory volume in 1 second (FEV1) Obstructive Lung Disease (GOLD) diagnostic criteria (GOLD Criteria 2020) and spirometry with the following documented parameters measured during Screening Visit 1 (prior to start of low-dose inhaled treprostinil): Diagnosis of PH-COPD (World Heath Organization Group 3).Ĭlinical diagnosis of COPD will be made using the Global Initiative for Chronic.Males with a partner of childbearing potential must agree to use a barrier method (condom) with a spermicide for the duration of treatment and for at least 48 hours after discontinuing study drug.Participants must have a negative pregnancy test at the Screening Visit 1 (urine and serum) and Baseline Visit (Study Week 1) (urine). Women of childbearing potential (defined as less than 1 year post-menopausal and not surgically sterile) must agree to practice abstinence or use 2 highly effective methods of contraception (defined as a method of birth control that results in a low failure rate,, such as approved hormonal contraceptives, barrier methods used with a spermicide, or an intrauterine device) for the duration of study treatment and for 48 hours after discontinuing study drug.Males and females 18 years of age and above at the time of informed consent. Participant voluntarily gives informed consent to participate in the study.Participants who meet the following criteria may be included in the study: Why Should I Register and Submit Results?.