A vascular graft for anastomosis of blood vessels or ducts comprises piercing means for engaging an end portion of a blood vessel or prosthesis and means for precisely guiding one or more piercing elements to pierce the wall of the vessel or prosthesis to a predetermined depth and in a predetermined direction. Advantageously, the inventive switches incorporate two-stage polarization rotation to improve isolation depth, as well as temperature and wavelength independence. The electronic unit is provided with supply and communication connection terminals, an electronic circuit, a sensor for reading initial reference positioning and a casing.