 10 isolated diabetic microangiopathia 11 implantated cardiac pacemaker or defibrillator 12 transcutaneous partial pressure of oxygen tcpO2 50 mmHg 13 concomitant disease with potential to limit the significance of the investigation of the walk distance angina pectoris, heart failure, relevant pulmonary disease, relevant orthopedic or neurologic disease 14 concomitant disease with potential to improve or to worsen the walking or the perfusion of the extremities in a relevant way. 