CASE PRESENTATION: A 56-year-old African American male diagnosed with iPAH who declined after several years on oral phosphodiesterase-5-inhibitor despite adding an endothelin-receptor-antagonist. Invasive hemodynamics demonstrated a mean pulmonary arterial pressure (mPAP) of 51, pulmonary vascular resistance (PVR) of 7 Woods units, and cardiac index (CI) 2. The renal panel was remarkable for a creatinine of 2.2 mg/dl and B natriuretic peptide (BNP) of 8,000. He had hemodynamic evidence of right ventricular failure, he was initiated on IV epoprostenol, titrated in response to his clinical status over several weeks to 22 ng/kg/min. His functional class and 6-minute-walk-test have improved, his BNP and creatinine level continued to rise to 90,000 and 3.9 respectively. He experienced a 20-pound weight gain. Invasive hemodynamics showed improvements, mPAP of 40, PVR of 4 Woods units, and CI of 5. He had renal failure with a sodium-avid state the fractional excretion of sodium (FENA) was < 1%. IV epropostenol was slowly tapered to 10ng/kg/min, CI fell (table1), renal function improved.