['Plasma levels of thrombomodulin are increased in diseases associated with microangiopathia. The target of this study was to examine whether plasma thrombomodulin is also influenced by macroangiopathia. There was no variation of plasma thrombomodulin in a sample of 183 diabetic patients with or without peripheral arterio-occlusive disease of the lower limbs. In a second sample of 33 patients with peripheral arteriosclerosis of the lower limbs, without any indication of diabetes, plasma levels of thrombomodulin were not significantly increased compared to a control group. Since thrombomodulin is also found in thrombocytes, we analysed whether plasma thrombomodulin levels were influenced by platelet activation. Neither platelet activation after hyperthermal limb perfusion not the PGE1-treatment showed any effect on plasma thrombomodulin level.'] Is [ Thrombomodulin a marker of microvascular , but not for macrovascular endothelial cell damage ]?