A branch vessel prosthesis for use with an aorta stent graft defining a lumen and having a fenestration aligned with a branch vessel, includes an expandable stent that has a tubular portion, a flareable portion, and at least one bending portion located between the tubular and the flareable portions. Upon deployment of the branch vessel prosthesis, the flareable portion is flared by bending of the bending portion.
