Flolan (Prostacyclin) is given continuously through an indwelling catheter.
A Randomized Controlled Trial of Epoprostenol Therapy for Severe Congestive Heart Failure: The Flolan International Randomized Survival Trial (FIRST). This study was for heart-failure patients (not PH patients), and the results were so bad the study was ended early, because the patients were dying off at an increased pace. Medscape.