A balloon is used for placing stents in bifurcated vessels. The balloon is for expanding a primary balloon-expandable stent, where the balloon includes a tubular balloon having a proximal end and a distal end, the balloon being capable of receiving within its tubular structure a primary guidewire for deployment of the primary stent, the balloon further comprising a side opening closer to the distal end than the proximal end through which a secondary guidewire and a secondary stent may pass.
