A stent is a tiny tube placed into an artery, blood vessel, or other duct (such as one that carries urine) to hold the structure open.

Drug-eluting stents; Urinary or ureteral stents; Coronary stents

When a stent is placed into the body, the procedure is called stenting. There are different kinds of stents. Most are made of a metal or plastic mesh-like material. However, stent grafts are made of fabric. They are used in larger arteries.

An intraluminal coronary artery stent is a small, self-expanding, metal mesh tube that is placed inside a coronary artery after balloon angioplasty to prevent the artery from re-closing.

A drug-eluting stent is coated with a medicine that helps further prevent the arteries from re-closing. Like other coronary stents, it is left permanently in the artery.

Most of the time, stents are used to treat conditions that result when arteries become narrow or blocked. The devices are also used to unblock and keep open other tube-shaped structures in the body, including the ureters (the tubes that drain urine from the kidneys to the bladder) and bronchi (the small windpipes in the lungs).

Stents are commonly used to treat the following conditions that result from blocked or damaged blood vessels:

• Coronary heart disease (CHD) (angioplasty and stent placement - heart)
• Peripheral artery disease (angioplasty and stent replacement - peripheral arteries)
• Renal artery stenosis
• Abdominal aortic aneurysm (aortic aneurysm repair - endovascular)
• Carotid artery disease (carotid artery surgery)

Other reasons to use stents include:

• Keeping open a blocked or damage ureter (percutaneous urinary procedures)
• Treating aneurysms, including thoracic aortic aneurysms
• Keeping bile flowing in blocked bile ducts (biliary stricture)
• Helping you breathe if you have a blockage in the airways

• Allergic reaction to stent material
• Allergic reaction to the drug used in a drug-eluting stent
• Blood clot
• Clogging of the inside of the stent (in-stent restenosis)
• Rupture of the duct or vessel when the stent is inserted

Boden WE, O'Rourke RA, Teo KK, et al. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med. 2007;356:1503-1516.

Lingeman JE, Matlaga BR, Evan AP. Surgical management of upper urinary tract calculi. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 44.