In endovascular thoracic aortic aneurysm repair, the surgeon inserts a thin, flexible tube called a catheter through an artery in the groin area and guides it to the aorta. A metal mesh tube called a graft is on the end of the catheter. The graft is placed at the aneurysm site. It's secured with small hooks or pins. The graft strengthens the weakened section of the aorta to prevent rupture of the aneurysm.