To elucidate the histologic changes after stent graft oversizing in nonatherosclerotic aortas using an experimental porcine model. We previously reported that the diameter and angulation of the aorta in this model are similar to those in young individuals who undergo stent graft repair for blunt aortic injuries. The lack of commercially available stent grafts specific for repairing blunt aortic injuries, particularly for small and angulated aortas, may be related to the high rate of endograft complications in this population.