Inclusion Criteria:  Patients with manifest PAD stages II-IV according to Fontaine or healthy volunteers Adult (>18 years) persons who are able to give their consent  Exclusion Criteria:  Patients with PAD stage I according to Fontaine Healthy volunteers with pre-existing diabetes mellitus, chronic renal failure, or abnormal ABI Underage persons Missing consent form Exclusion due to safety concerns of the study physician (patient with a physical, mental or psychiatric illness which, in the opinion of the study physician, would compromise the safety of the patient or the quality of the data and thus make the patient an unsuitable candidate for the study)