[Blood rheological changes and their clinical significance in chronic arterial obstructive disease]

New knowledge about the physiology and pathophysiology of the flowing properties of blood, particularly in the area of microcirculation, led to a better understanding of the pathogenesis of the arterial obstructive disease. When the vasomotor reserve is kept, the blood fluidity authoritatively determines the flow-time-volume depending on the conditions of flow. An increase of the blood and plasma viscosity as well as a decreased fluidity of erythrocytes and an increased aggregation of erythrocytes lead over an impairment to the nutritive capillary blood supply to hypoxic tissue damage. Physico-chemical changes of the milieu, such as lactacidosis and hyperosmolarity may additionally cause local rheological disturbances and contribute to a reduced perfusion. The improvement of the flowing properties of the blood takes at present place essentially by haemodilution and reduction of fibrinogen. The possibly most hopeful way to the reduction of blood viscosity consists in the immediate improvement of the fluidity of erythrocytes. Here up to now the xanthine derivative pentoxifylline showed good results in the clinical practice.