A catheter assembly may include a main balloon arranged to reside within the main vessel, and a branch balloon configured to extend from the main vessel into the branch vessel. A stent may be situated around the main balloon and may include a branch aperture at a location between proximal and distal open ends of the stent. The branch balloon may extend from within the stent, through the branch aperture, and into the branch vessel. The branch balloon, when inflated, may extend into the branch vessel. The main balloon, when inflated, may also expand the stent within the main vessel. In some arrangements, the branch balloon, when inflated, can function as an anchor within the branch vessel that resists radial and axial movement of the stent relative to the branch vessel and main vessel during expansion of the stent by the main balloon.