Bolus milrinone was not effective for decreasing PAP, and norepinephrine was replaced with arginine vasopressin (AVP) 0.2 units bolus repeatedly, followed by continuous infusion at 1.6 units/h, which effectively ameliorated pulmonary hypertension The AVP dose was reduced to 0.7 units/h and totally, administered for 40 min. The gene discussed is AVP; the disease is pulmonary arterial hypertension.