Impaired hemorheological properties in diabetic patients with lower limb arterial ischaemia.

The rheological properties of blood play an important role in the regulation of blood flow resistance in vessels. Numerous data show evidence for an impaired hemorheological characteristic in diabetes mellitus. The aim of this study was to investigate whether chronic severe leg ischaemia in diabetes may be associated with further hemorheologic impairment. To do this, whole blood viscosity, erythrocyte aggregation/disaggregation, plasma viscosity and proteins were measured in 32 healthy control subjects, in 32 diabetic patients without micro- and macroangiopathy, in 21 diabetic patients with chronic tissue hypoxia of lower limbs and in 23 diabetic patients with severe leg ischaemia. The diabetic patients with leg hypoxia and leg ischaemia were selected according to their value of transcutaneous oxygen pressure (TcPO2) measured on dorsal side of the foot in supine position. The TcPO2 value was within 10-30 mmHg or less than 10 mmHg in patients with chronic hypoxia and severe ischaemia, respectively. Results in diabetic patients without micro- and macroangiopathy showed an increased erythrocyte aggregation associated with an increased fibrinogen level while albumin levels were decreased. Both diabetic patients with chronic hypoxia and those with severe ischaemia exhibited similarly more aggravated hemorheological disturbances including an increased whole blood viscosity at low shear rate, an increased erythrocyte hyperaggregation, increased plasma viscosity, increased fibrinogen level, decreased albumin level and decreased hematocrit. In conclusion, the hemorheological disturbances are present even in diabetic patients without clinically detectable micro- and/or macroangiopathy. The fact that the extent of disturbances was similar in the two later diabetic groups, emphasizes that the hemorheological disturbances are not the consequences of chronic hypoxia and/or severe ischaemia but are likely among factors promoting the maldistribution of blood flow in nutritive capillaries as evidenced by decreased TcPO2 in patients with chronic leg hypoxia or severe leg ischaemia.