A stent is a tiny mesh tube that is inserted into a vessel to reshape the vessel walls. They are often inserted into blood vessels that have been narrowed by plaque buildup (atherosclerosis) or due to collapse. Angioplasty is often performed to widen the blood vessel, then a stent is placed inside the blood vessel to prevent the blood vessel from collapsing or narrowing again. Stents are also placed as stent grafts to create new vessel walls in the case of abdominal aortic aneurysm (AAA).
Stent placement is a catheter-based procedure. The catheter carries the stent to the location of the narrowed or collapsed blood vessel, then the stent is placed in position, possibly as part of the balloon angioplasty procedure.