A percutaneous trans-luminal catheter delivery system for an implant, the system comprising: a catheter shaft with a distal end to carry the implant and a proximal end, and an elongate housing at the proximal end that an operator can grasp when deploying the implant; the shaft having an inner push component which can push on the implant in a distal direction and an outer sheath component which radially surrounds the implant until said deployment of the implant into the bodily lumen, the outer sheath component being capable of being pulled proximally, from the housing, to deploy the implant; the housing being mounted on a proximal end portion of the push component and defining a channel; the housing containing a sheath slitter that is fixedly mounted relative to the length of the channel and that can slit the outer sheath as the outer sheath is caused to move proximally in the channel relative to the slitter.