 Critical limb ischemia CLI occurs when the peripheral microcirculation is impaired by arterial stenoses or occlusions. In opposite to earlier studies that only evaluated intermittent claudication due to peripheral arterial disease PAD, rest pain and trophic changes in the affected extremity are due to reduced microcirculation. Though the main reason for CLI is the existing PAD, many processes responsible for pain and other pad-associated symptoms are triggered by a reduced microcirculation so that attempts to enhance the dermal perfusion by pharmacological or other manipulations may ameliorate the results of vascular treatment. These attempts may be the best options for patients, in which vascular surgery was not successful or primarily impossible. 