Treatment of pulmonary hypertension with the continuous infusion of a prostacyclin analogue, iloprost

Objective—To compare prostacyclin with an analogue, iloprost, in treatment of severe pulmonary hypertension.
Patients—Eight patients with severe pulmonary hypertension: primary in five, thromboembolic pulmonary hypertension in three.
Methods—All patients underwent right heart catheterisation. Mean (SEM) right atrial pressure was 9.9 (2.2) mm Hg, mean pulmonary artery pressure 67.4 (3.0) mm Hg, cardiac index 1.75 (0.13) l/min/m² and mixed venous oxygen saturation 59.1(3.1)%. Continuous intravenous epoprostenol (prostacyclin, PGI₂) or iloprost was given for phase I (three to six weeks); the patients were then crossed over to receive the alternate drug in an equivalent phase II.
Main outcome measures—Exercise tolerance was measured at baseline and at the end of phase I and II with a 12 minute walk; distance covered, rest period, percentage drop in arterial oxygen saturation (ΔSaO₂%) and percentage rise in heart rate (ΔHR%).
Results—Walking distance covered rose from (mean (SEM)) 407.5 (73) to 591 (46) m with PGI₂ (p = 0.004) and to 602.5 (60) m while on iloprost (p = 0.008). Rest period decreased from 192 (73) seconds at baseline to 16 (16) seconds with PGI₂ (p = 0.01) and to 58 (34) seconds with iloprost (p = 0.008). ΔHR% was 37.5(6)% at baseline, 35(3)% on PGI₂, and 24(6)% on iloprost (p = 0.04).
Conclusions—Both intravenous PGI₂ and iloprost caused significant improvement in exercise tolerance. Iloprost offers an alternative to PGI₂ treatment of severe pulmonary hypertension.

Keywords: prostacyclin;  vasodilatation;  iloprost;  pulmonary hypertension