Plasma endothelin levels during iloprost infusion in patients with critical leg ischaemia

Abstract

We studied the behaviour of plasma endothelin levels in 7 elderly patients with critical limb ischemia, during iloprost infusion with the aim to clarify both the interaction among various vasoactive endothelial substances and the endothelin importance in atherosclerotic disease development. Iloprost (diluted with saline solution in a concentration of 200ng/ml) was administered intravenously, from 30 to 40 ml/h, for six hours/day and for 4 weeks. Plasma endothelin concentration was determined on the 4th day of treatment at time intervals of 0, 2, 4, 6 and 8 hours: i.e. before the beginning of the infusion, then every two hours till the sixth hour and two hours after the end of iloprost infusion. The control group was composed by 7 subjects matched for age affected by peripheral obliterant arterial disease at the I and II Fontaine stage: only saline solution was administered to them. The mean ± SD plasma endothelin level of patients in iloprost infusion was 5.40 ± 1.23 pg/ml at T0, 4.24 ± 0.72 pg/ml at the second hour, 4.22 ± 0.74 pg/ml at the fourth hour, 4.24 ± 0.22 pg/ml at the sixth hour and 4.49 ± 0.58 pg/ml at eighth hour. The difference between basal endothelin level and that of the second, fourth and sixth hour was statistically significant (p<0.05) while that of the eighth hour was not. In the control group the means ± SD plasma endothelin levels were respectively 5.23 ± 0.55 pg/ml, 4.88 ± 1.39 pg/ml, 5.44 ± 1.51 pg/ml, 5.10 ± 0.86 pg/ml and 5.60 ± 1.64 pg/ml at the same intervals The difference between the basal endothelin level and the successive ones was not statistically different. In atherosclerosis the endothelial contracting factors become more important whereas the formation and/or effects of the relaxing factors are impaired. Iloprost infusion, therefore, may restore physiological equilibrium among various vasoactive substances, so that tissue perfusion is further improved.