A fixator assembly comprising a fixator for fixing inside a blood vessel, the fixator being able to slide proximally along a guide wire. The assembly comprising means for preventing the fixator from moving distally of the preventing means. A tubular element for introduction into a blood vessel of a person, the tubular element comprising an end opening and a plurality of side openings as well as a transport wire extending from inside the tubular element and to the surroundings thereof through an individual side opening.