Oral Treprostinil in Subjects With Pulmonary Hypertension Associated With Heart Failure With Preserved Ejection Fraction

Inclusion Criteria: 1. The subject voluntarily gave informed consent to participate in the study. 2. The subject was 18 to 85 years of age (inclusive) at Screening (ie, date of providing written informed consent). 3. A subject could qualify if they had undergone a right heart catheterization (RHC) within 180 days of Baseline. 4. The subject had a diagnosis of heart failure with a left ventricular ejection fraction (LVEF) ≥45% by ECHO completed during Screening (prior to randomization). 5. The subject's baseline 6MWD was at least 150 meters. 6. The subject had pulmonary function tests conducted within 6 months of Screening or during the Screening Phase. 7. Subjects on a chronic medication for heart failure were on a stable dose for ≥30 days prior to randomization. 8. In the opinion of the Investigator, the subject was able to communicate effectively with study personnel, and was considered reliable, willing, and likely to be cooperative with protocol requirements, including attending all study visits. 9. Women of childbearing potential, including any female who had experienced menarche and who had not undergone successful surgical sterilization or was not postmenopausal, must have practiced true abstinence from intercourse when it was in line with their preferred and usual lifestyle, or have used 2 different forms of highly effective contraception for the duration of the study, and for at least 30 days after discontinuing study drug. Male subjects with a partner of childbearing potential must have used a condom during the length of the study, and for at least 48 hours after discontinuing study drug. 10. Subjects on chronic medications (eg, inhaled corticosteroids, long-acting beta2 adrenergic agonist, long acting muscarinic antagonists, combination inhaled drugs, anti-inflammatory drugs, oral/parenteral corticosteroids, or biologic agents) for any underlying respiratory condition were on a stable dose for ≥30 days prior to randomization. Exclusion Criteria: 1. The subject was pregnant or lactating. 2. In the opinion of the Principal Investigator, the subject had a primary diagnosis of PH other than WHO Group 2 PH. 3. The subject had shown intolerance or significant lack of efficacy to a prostacyclin or prostacyclin analogue that resulted in discontinuation of therapy or inability to effectively titrate that therapy. 4. The subject had received any approved pulmonary arterial hypertension (PAH) therapies within 30 days of randomization. Chronic use of an approved phosphodiesterase type 5 inhibitor (PDE5-I) was allowed as long as the subject has been on a stable dose for at least 90 days prior to randomization and had a RHC confirming the parameters necessary for inclusion in the study after being on a stable PDE5-I dose for at least 30 days. 5. The subject had been hospitalized for a cardiopulmonary indication within 30 days of randomization. 6. The subject had a myocardial infarction within 90 days of randomization. 7. The subject had cardiac resynchronization therapy within 90 days of randomization or anticipated resynchronization therapy during the study treatment period. 8. The subject had liver function tests greater than 3 times the upper limit of normal at Screening, clinically significant liver disease/dysfunction, known Child-Pugh Class C hepatic disease, or noncirrhotic portal hypertension. 9. The subject had uncontrolled systemic hypertension, systolic blood pressure \<100 mmHg, or a resting heart rate \>100 beats per minute at Baseline. 10. The subject had known genetic hypertrophic cardiomyopathy, sarcoidosis, or cardiac amyloidosis. 11. The subject had a known history of any LVEF less than 40% by ECHO within 3 years of randomization. Note: a transient decline in LVEF below 40% that occurred and recovered more than 6 months before the start of Screening and was associated with an acute intercurrent condition (eg, atrial fibrillation) was allowed. 12. The subject had hemodynamically significant valvular heart disease as determined by the Investigator, including: greater than mild aortic and/or mitral stenosis or severe mitral and/or aortic regurgitation (\>Grade 3) 13. The subject had a Body Mass Index \>45 kg/m\^2. 14. The subject had any musculoskeletal disorder, or had any other condition that limited ambulation. 15. The subject had end-stage renal disease requiring/receiving dialysis. 16. The subject participated in an investigational drug or device study within 30 days prior to the first dose of study drug.