STENT - A stent is a tiny tube that your doctor can insert into a blocked passageway to keep it open. The stent restores the flow of blood or other fluids, depending on where it’s placed. Stents are made of either metal or plastic. Stent grafts are larger stents used for larger arteries. They may be made of a specialized fabric. Stents can also be coated with medication to help keep a blocked artery from closing. Stents are usually needed when plaque blocks a blood vessel. Plaque is made of cholesterol and other substances that attach to the walls of a vessel. You may need a stent during an emergency procedure. An emergency procedure is more common if an artery of the heart called a coronary artery is blocked. Your doctor will first place a catheter into the blocked coronary artery. This will allow them to do a balloon angioplasty to open the blockage. They’ll then place a stent in the artery to keep the vessel open. Stents can also be useful to prevent aneurysms from rupturing in your brain, aorta, or other blood vessels. Besides blood vessels, stents can open any of the following passageways: • bile ducts, which are tubes that carry bile to and from digestive organs • bronchi, which are small airways in the lungs • ureters, which are tubes that carry urine from the kidneys to the bladder These tubes can become blocked or damaged just like blood vessels can.