Abdominal Aortic Stent Graft Mechanics: Sizing Them Up

An abdominal aortic aneurysm (AAA) of the aorta is a local widening of the aorta in a region between the renal arteries and the aortic bifurcation. The disease impacts the structural integrity of the AAA wall, weakening the tissue and predisposing it to rupture. Preventive treatment of the disease is often performed minimally invasive with endovascular repair by stent graft deployment, as an alternative to open surgical repair. During endovascular aneurysm repair, a metallic stent, covered with a polymer membrane is first crimped and mounted onto the delivery system and inserted through the iliac artery. It is advanced to the AAA region, and expanded to cover the weakened, ballooning aorta. The technique has excellent clinical outcome, yet it is still associated with long term problems such as migration, a downward displacement of the device, and endoleakage, with blood reentering and pressurizing the aneurismal sack.