A system and method for repairing one or more vessels includes a branch vessel prosthesis (11) for use with an aorta stent graft (1) defining a lumen and having a fenestration (7) aligned with a branch vessel. The branch vessel prosthesis includes a flaring portion (36) and a tubular portion (33), where the flaring portion is retained within the lumen of the aorta stent graft and the tubular portion passes through the fenestration and into the branch vessel.