Vascular endoscopy, especially of the venous system, allows a tri-dimensional evaluation and represents, to date, the best possible per-operative control of the diameter of the vessel. Under these conditions, venous thrombectomy may be performed more accurately; residual adherent parietal thrombi which may represent a possible source of emboli, may be eliminated. Venous endoscopy may be repeated several times; it does not result in any X-Rays exposure for the patient and enables to diagnose finer morphological details. Therapeutic measures under direct vision could even become possible in the future.