A comparison of the acute hemodynamic effects of inhaled nitric oxide and aerosolized iloprost in primary pulmonary hypertension

OBJECTIVE We sought to compare the acute hemodynamic effects of inhaled nit ric oxide (NO) and aerosolized iloprost in primary pulmonary hypertension ( PPH). BACKGROUND Inhalation of the stable prostacyclin analogue iloprost has rece ntly been described as a novel therapeutic strategy for PPH and may offer a n alternative to continuous intravenous infusion of prostacyclin or inhalat ion of NO. METHODS During right heart catheterization, 35 patients with PPH sequential ly inhaled 30 ppm of NO and 14 to 17 mu g of iloprost, and the effects on h emodynamics and blood gases were monitored. RESULTS Both NO and iloprost caused significant increases in cardiac output , mixed-venous oxygen saturation and stroke volume as well as significant d ecreases in pulmonary artery pressure and pulmonary vascular resistance, wh ereas only inhaled iloprost significantly increased the arterial Po-2 (p = 0.01). Compared with inhaled NO, aerosolized iloprost was more effective in reducing pulmonary artery pressure (-8.3 +/- 7.5 mm Hg vs. -4.3 +/- 8.8 mm Hg; p = 0.0001) and the pulmonary vascular resistance (-447 +/- 340 dynes. s.cm(-5) vs. -183 +/- 305 dyne.s.cm(-5); p < 0.0001). Furthermore, aerosoli zed iloprost caused a significantly greater increase of the cardiac output compared with NO (+0.7 +/- 0.6 liter/min vs. +0.3 +/- 0.4 liter/min; p = 0. 0002) and had a more pronounced effect on the mixed-venous oxygen saturatio n (p = 0.003). CONCLUSIONS During acute drug testing, aerosolized iloprost was more potent than inhaled NO as a pulmonary vasodilator in PPH at the doses used in thi s study. (C) 1999 by the American College of Cardiology.