An endovascular system (10) includes an endovascular implant (20) and a delivery tool (30). The implant (20) is configured to assume a radially-compressed delivery state, and a radially-expanded deployment state. The delivery tool (30) includes a proximal main delivery catheter (36), having a distal portion (46) in which the implant (20) is disposed while in the radially-compressed delivery state; and a distal restraining assembly (50), which includes a restraining-assembly tubular shaft (52) disposed distal to the proximal main delivery catheter (36). The distal restraining assembly (50) is configured to assume an engaged state, in which the distal restraining assembly (50) prevents proximal displacement of the implant (20) relative to the distal restraining assembly (50), and a disengaged state, in which the distal restraining assembly (50) allows proximal displacement of the implant (20) relative to the distal restraining assembly (50). Other embodiments are also described.