The first percutaneous transluminal angioplasty (PTA) was performed by Dotter and Judkins in 1964 . Since then this technique has become a major interventional procedure in medicine. Over the past 8 years 4750 patients have undergone PTA at Freiburg University Hospital and Hochrhein Hospital in Bad Säckingen. A critical evaluation of complications and long-term results of this method have been reported based on this research [10, 13, 22]. Despite these long-standing experiences with this primarily angiographic method it is difficult in some patients to determine the definitive extension of the vascular disease from the angiographic radiograph and to decide whether to perform PTA. The starting point for the introduction of angioscopy was the question of whether endoscopy could add essentially new information to routine radiological investigations, and whether it was of any help in vascular interventional procedures. It was asked whether angioscopy could help in finding new criteria for pathological vascular processes that would improve the assessment of prognosis and thereby improve the assessment of prognosis and thereby improve therapeutic management of the patient.