An endoluminal vascular repair system includes an aorta stent graft having a fenestration with a first reinforcement around the fenestration. The fenestration aligns with a branch vessel when deployed. A branch vessel stent graft has a flaring portion at a proximal end of the branch vessel prosthesis that has a second reinforcement around its circumference to engage the reinforcement around the fenestration, and a tubular portion. When deployed, the flaring portion retains the proximal end within the aorta stent graft, and the tubular portion extends through the fenestration and into the branch vessel.
