Primary pulmonary hypertension (PPH) is a progressive disease with frequent morbidity and mortality, including the risk of cardiac decompensation and death, during general anesthesia. Administration of IV epoprostenol (Flolan) improves symptoms and survival of patients with PPH and thus is an increasingly used long-term treatment for this condition. This therapy is associated with impaired platelet aggregation, which may complicate the perioperative management of patients with PPH. We present a case report of a patient with severe PPH receiving a continuous epoprostenol infusion undergoing skin grafting for a leg ulcer under spinal anesthesia. An IV infusion of vasopressin was given to prevent systemic hypotension resulting from sympathetic blockade while avoiding increases in pulmonary vascular resistance that may have resulted from catecholamine usage.