A randomized,double blind,placebo-controlled,cross-over trial on isovolemic hemodilution in claudicants – preliminary results

Abstract

Presently the clinical efficacy of hemodilution in peripheral vascular disease is only supported by uncontrolled trials. This is a preliminary report about results obtained in a randomized placebo-controlled, double blind, cross-over study. Fourteen male patients with stable intermittant claudication, hematocrit higher than 45%, walking distance between 200 and 300 m and subtotal stenosis or obstruction of a femoral artery with good collateralization were admitted. Isovolemic hemodilution was performed three times per week with 500 ml of 10% hydroxyethyl starch (200) for three weeks. This was followed by a “wash-out” period of two weeks. Finally a three weeks’ period of regular “sham” dilutions was introduced, which for the patient appeared identical to hemodilutions, but where no blood was exchanged. This regim was randomly executed for- or backwards. To keep double blind standards, clinical assessment of the patients (maximal walking distance on a treadmill and plethysmogram) was done by a third party and hemorheological measurements (blood viscosity and hematocrit) by a forth party. Results show that “sham” dilutions did not induce any positive changes, while hemodilution resulted in a significant fall of hematocrit and blood viscosity paralleled by a significant rise in walking distance and resting blood flow.