TReatment Of Pulmonary HYpertension 1-US Study

Inclusion Criteria: * Patient with known pulmonary arterial hypertension (PAH), diagnosed as idiopathic PAH, connective tissue disease PAH, Anorexogen induced or Heritable PAH * PAH diagnosis confirmed by hemodynamic evaluation performed prior to screening and showing all of the following: Mean pulmonary artery pressure (mPAP) ≥25 mmHg at rest; Pulmonary capillary wedge pressure (PCWP) or left ventricular end diastolic pressure (LVEDP) ≤15 mmHg; Pulmonary vascular resistance (PVR) at rest \>3 Wood units; Not meeting the criteria for a positive vasodilator response (fall in mPAP ≥ 10 mmHg to ≤ 40 mmHg). * Patient with a current diagnosis of WHO functional class III * Patient taking two pulmonary arterial hypertension specific medications other than parenteral prostanoids * Patient is adhering to a stable drug regimen (i.e., with no changes of dose or medication for a minimum of 3 months prior to enrollment) * Patient with eGFR levels of ≥ 30 ml/min/1.73m2or serum creatinine levels of ˂ 150µmol/l Exclusion Criteria: * Patients who are treated with parenteral prostanoids * Pregnant women or women planning a pregnancy within 12 months of study enrolment * Patient with significant co-morbid condition(s) which, at the discretion of the PI, are deemed to prohibit study entry * Patient with life expectancy of less than a year * Concurrent enrollment in another device or drug trial except for observational studies (unless specifically approved by the sponsor) * Patient with pulmonary artery anatomy that precludes treatment * Patient with moderate to severe pulmonary artery stenosis * Patient with any pulmonary artery aneurysm * Patient who has experienced a myocardial infarction, unstable angina pectoris, or a cerebrovascular accident in the previous 6 months * Patient who has implantable cardiac pacemakers, ICDs, neurostimulators, or drug infusion devices * Patients who are unable to undergo an MRI scan