The invention provides a delivery system for a prosthesis, said deliverysystem comprising a catheter shaft with adistal end, a proximal end and a longitudinal axis, a space for a prosthesiswith a distal end and a proximal end, the space being atthe distal end of the catheter shaft, a sheath with a proximal end and adistal end, the sheath being disposed at the distal end of thecatheter shaft so as to surround the space, a pusher element attached to thedistal end of the catheter shaft and arranged at theproximal end of the space for abutting prosthesis, a pull element with alongitudinal axis, the pull element running the length ofthe catheter shaft and having a distal end attached to the proximal end of thesheath and a proximal end for pulling the pullele-ment proximally, thereby retracting the sheath proximally relative to theprosthesis space, and at least one fixation element havinga proximal end and a distal end and being disposed within a flexible portionof the length of the shaft that lies between theproxi-mal end of the sheath and the proximal end of the catheter shaft. Thefixation element serves to limit a radial distance between theaxis of the pull element outside the shaft and the axis of the catheter shaftalong the length of the fixation element whenever aten-sile stress in the pull element results in an endwise compressive stresson the shaft and a tendency of the shaft to bow, relative tothe pull element.
