A method for deploying an expandable implant in a body passage of varying diameter includes selecting a balloon having a radial dimension that varies, when the balloon is inflated, in accordance with the varying diameter of the body passage. The balloon is inserted, in a deflated state, into the body passage, with the expandable implant fitted radially around the balloon. The balloon is inflated so as to cause the implant to open, responsively to the varying radial dimension of the balloon, into an expanded shape that approximately matches the varying diameter of the body passage, thus anchoring the implant in the body passage.
