This is an open label phase 2 pilot study designed to evaluate the safety, tolerability and device performance of the GeNO nitrosyl delivery system during right heart catheterization (RHC) in participants with pulmonary arterial hypertension (PAH). All participants will receive inhaled nitric oxide in oxygen or nitric oxide in air delivered by nasal cannula. Hemodynamics, clinical laboratory and clinical assessment data will be collected on all participants to evaluate safety.

TREATMENT/FOLLOW-UP:

Participants meeting eligibility criteria will receive open label nitric oxide at 80 ppm via a nasal cannula. Hemodynamic clinical laboratory and clinical assessment data will be collected at baseline, after 15 minutes of inhaled nitric oxide administration, post RHC procedure and at hospital discharge. Day 5 +/- 3 post RHC, telephone contact to assess general health status.

Inclusion Criteria:

• Have a confirmed diagnosis of PAH, WHO Group 1.
• WHO Functional Class II or III equivalent, PAH.
• Have been clinically stable with regard to signs and symptoms of PAH for at least 30 days prior to RHC.
• May be receiving approved mono therapies or combination PAH therapies.
• Females that are surgically sterile or post-menopausal. Females of chil-bearing potential must have negative pregnancy test and must be practicing adequate birth control.

Exclusion Criteria:

• Have had a new type of chronic therapy (including but not limited to oxygen, a different category of vasodilator, a diuretic, digoxin) for PAH added within (1) month of RHC.
• Have any PAH medication except for anticoagulants discontinued within the week prior to RHC.
• Have evidence of significant parenchymal lung disease as evidenced by pulmonary function tests within the last six months
• CREST (calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) syndrome
• Have a history of uncontrolled sleep apnea within three months of RHC.
• Have a history of hemodynamically significant left-sided heart disease
• Have evidence of left-sided heart disease
• Have any other disease that is associated with pulmonary hypertension (e.g. congenital systemic-to-pulmonary shunt, sickle cell anemia, schistosomiasis).
• Documented uncontrolled systemic hypertension as evidenced by systolic blood pressure greater than 160 mmHg or diastolic blood pressure greater than 100 mmHg.
• Have used prescription appetite suppressants within 3 months prior to wean/transition.
• Have chronic kidney disease stage IV or worse or the requirement for dialysis.
• Be receiving an investigational drug, have in place an investigational device, or have participated in an investigational drug study within the past 30 days.
• Have had an atrial septostomy.
• Have anemia (hemoglobin <10 g/dL), active infection or any other ongoing condition that would interfere with the interpretation of study assessments.
• Have any serious or life-threatening disease other than conditions associated with PAH (e.g. malignancy requiring aggressive chemotherapy, renal dialysis, etc.).
• Have unstable psychiatric status or be mentally incapable of understanding the objectives, nature or consequences of the trial
• Participant is pregnant or lactating
• Significant, ongoing alcohol or drug abuse.