Reduced amputation rate with isovolemic hemodilution in critical limb ischemia patients

AIMS: Critical limb ischemia (CLI) patients are characterized by intractable pain in spite of medication, non-healing ulcers, and gangrene. The objective of this study was to investigate whether or not isovolemic hemodilution treatment can reduce the rate of major amputations in CLI. METHODS: 28 patients were studied who had tissue loss on Rutherford Grade III, Category 5 or 6. The subjects were divided into two arms: standard-of-care, conventional therapy (CT) (n = 15) as a control group and hemodilution therapy (HT) (n = 13) as a study group. For the HT group, weekly isovolemic hemodilution was performed over 4 consecutive weeks, removing 250 ml of whole blood with the infusion of hydroxyl-ethyl starch solution. Blood viscosity, hematocrit, hemoglobin, ankle-brachial index, VA pain scale, time-to-amputation from admission, and survival time were measured. RESULTS: The mean Hct gradually decreased from 36.6 to 35.1, whereas the WBV at a shear rate of 1 s-1 significantly decreased from 18.2 to 10.5 during the same period. Subsequently, tissue oxygen delivery index, defined as the ratio of Hct to WBV at a shear rate of 1 s-1, increased from 24.4 to 37.0 by 51.7%, suggesting improvements in oxygen delivery in the patients. The average rate of lower limb major amputation in the control group was 93% (14/15), whereas that in the study group was 31% (4/13) (p = 0.001). Amputation-free median survival time and amputation-free 5-year survival rate in the control group were 1.2 months and 7%, while those in the study group were 30.2 months and 44% (p = 0.001). There were no adverse effects from repetitive hemodilution in the study group. CONCLUSIONS: Isovolemic hemodilution treatment of CLI patients was found to be well-tolerated and reduced the rate of major amputation resulting from the deterioration of CLI.