Effect of Iloprost infusion on metabolism in critical limb ischemia, utilizing microdialysis. A pilot study

In critical limb ischemia (CLI), the prognosis to keep the leg is poor if revascularisation is not possible. Treatment with prostanoids has proven to be beneficial regarding pain relief, ulcer healing and limb salvage but only in a proportion of patients. Prostanoids exert their effect in different ways e.g. on white blood cells and endothelial cells. No study has so far investigated the effect of prostanoids on the local tissue metabolism. The aim of this study was to investigate if infusion of the prostacyclin analogue, iloprost (PGI2) improves the local metabolism measured by microdialysis technique.

Eleven patients, 7 men and 4 women, median age 75 years (range 64-89 years), suffering CLI (Fontaine stage III and IV), were included. Patients with insulin dependent diabetes mellitus were excluded. Microdialysis catheters (CMA 60) were inserted subcutaneously in the ischemic leg and in the pectoral region, respectively. An iloprost infusion was given for 6 hours during 3 days preceded by a control day. Registrations of glucose and lactate levels were performed hourly.

No significant differences were found in lactate or glucose levels over the treatment period but a trend of increasing glucose and decreasing lactate was observed. Compared to the control day, lactate was significantly lower during (p=0.02) and after (p<0.05) the infusion. This was also true for the reference catheter during the infusion period (p=0.02).

No immediate improvement in glucose or lactate levels in ischemic tissue could be observed after 3 days of iloprost infusion, but a significant lactate decrease was found compared to a previous control day, suggesting a possible metabolic response.