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

Abstract

To compare prostacyclin with an analogue, iloprost, in treatment of severe pulmonary hypertension. Eight patients with severe pulmonary hypertension: primary in five, thromboembolic pulmonary hypertension in three. 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. 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 (delta Sao2%) and percentage rise in heart rate (delta HR%). 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). Delta HR% was 37.5(6)% at baseline, 35(3)% on PGI2, and 24(6)% on iloprost (p = 0.04). Both intravenous PGI2 and iloprost caused significant improvement in exercise tolerance. Iloprost offers an alternative to PGI2 treatment of severe pulmonary hypertension.