WHO group IV and V pulmonary hypertension

Patients who are on baseline pulmonary vasodilator medications

Severe aortic or mitral valve disease

Patients who are pregnant

Left ventricular ejection fraction of \<35%

Patients who are hospitalized as inpatients at the time of RHC

Patients with systolic blood pressure \<90mmHg or mean arterial pressure of \< 60mmHg

Comparison of Vasodilator Response of Inhaled Epoprostenol and Inhaled Nitric Oxide