Problem: A patient being started on an agent to treat pulmonary arterial hypertension.The past has a past medical history of hypertension, acute coronary syndrome and moderate livder disease. The patient home meds are lisinopril, nadolol, rifaximin, lactulose and nitro PRN. Given the medical history and home medication list for the patient, what is the BEST agent for chronic thromboembolic pulmonary hyperttensionc