A device for detaching parietal thrombi from a bodily vessel is described, said device having a catheter, along the catheter longitudinal extent of which at least one catheter section is provided in which the associated catheter wall has at least one wall opening which passes completely through the catheter wall. The invention is characterised in that the catheter wall along the least one catheter section is made of a resiliently deformable material, in that the at least one wall opening is designed as a separating gap winding helically around the catheter wall at least in parts along the catheter section, in that the catheter has, in the distal direction from the wall opening, a fixing means which permits releasable fixing of the catheter on a bodily vessel, in that the catheter can be converted, exclusively by an external mechanical constraint in the form of a torque acting torsionally on the catheter, from a state with a relatively small catheter outer diameter to a state with a relatively large catheter outer diameter, by way of a resilient change in shape, wherein the helically winding separating gap widens from a closed gap state to an opened gap state, and in that the catheter, in the absence of the external constraint, spontaneously adopts the state with the relatively small catheter outer diameter, due to the resilient restoring forces inherent to the material, and the separating gap adopts the closed gap state.
