A system for placing an expandable medical device in a bifurcated body lumen, the system comprising: a balloon adapted to be inflated by an inflation pressure； and an expandable medical device 100 into which the balloon is insertable, the expandable medical device 100 having a differentially expandable structure comprising a first section 104 and a second section 102, wherein the first section 104 is configured to expand at a lower inflation pressure than the second section 102.
