Effects of iloprost, either administered for 1 week or 4 weeks, on systemic hemodynamics, peripheral blood flow, and exercise tolerance in patients with peripheral occlusive arterial disease at Leriche-Fontaine stage III

Twenty patients, 15 males and 5 females, aged 50-71 years, with peripheral obstructive arterial disease at Fontaine stage III and requiring hospitalization, were randomized to two different iloprost treatment schedules: iloprost i.v. infusion, up to 2 ng/kg/minute for 6 hours/day for 28 days (Group A) or iloprost i.v. infusion, up to 1.5 ng/kg/minute, for 16 hours/day for 7 days (Group B). At baseline, after 7 days (end of treatment, Group B only) and after 28 days (end of study) the following measurements were done: blood pressure and heart rate, ankle/arm pressure index, first flow, peak flow, time to regression (by means of mercury strain-gauge plethysmography), stroke volume, cardiac output, ejection fraction (by means of 2D-echocardiography and echo-Doppler), exercise tolerance (by means of treadmill test), and rest pain (by means of visual analogue scale). Both treatment schedules resulted in significant improvement in plethysmographic parameters and exercise tolerance (both maximal and pain free) with concomitant reduction in rest pain. These effects were long lasting as evident by the results observed in Group: B where the absolute data after 3 weeks of drug withdrawal were superimposable to those of Group A. On the contrary, only mild effects were evident on systemic hemodynamics, which tended to wane off as the infusion was stopped. From the results of this pilot study it is possible to conclude that treatment with iloprost at lower dosage (up to 1.5 ng/kg/minute) for 16 hour/day for 7 days, in patients at Fontaine stage III, seems to result in the same therapeutic benefits of the currently used schedule (up to 2 ng/kg/minute for 6 hour/day for 28 days). If confirmed by larger clinical experience, these data have clear implication in terms of patient comfort and cost containment.