Abstract: The inventive expansion catheter has a catheter tube (11) and a perfusion tube (12) which can be moved inside the catheter tube (11). The perfusion tube (12) is connected to a stent (13) formed of a wire-type material. The stent (13) is constricted by the catheter tube (11). When, the catheter tube (11) is withdrawn, the stent (13) expands, hereby taking up two expansion areas, (16, 18) which border an area (26) to be protected from the pressure of the blood. A bypass (28) can be fixed in this area (26) by means of an anastomosis (27). The perfusion tube (26) ensures that the blood vessel (21) is supplied behind the obturation point so that the operation can be carried out as non-invasively as possible while the heart is beating.