A stent is a tiny metal or fabric tube that is used to keep clogged arteries open or to shore up weakened arteries, according to the National Heart Lung and Blood Institute, or NHLBI. Stents are sometimes coated with drugs that help keep arteries open. They are usually placed during a procedure called angioplasty, in which a tiny balloon is inserted into an artery and then inflated to widen the blood vessel. Complications of stent placement are unusual but there are risks.
Angioplasty Risks
During an angioplasty, a thin tube called a catheter is inserted into a blood vessel, often in the leg, and maneuvered up through the blood vessels to where the balloon and stent need to be placed. The catheter can cause bleeding where it is inserted and can damage blood vessels on its way through the body, according to the NHLBI. There is also a risk of infection and irregular heartbeat. Dye is used in the procedure to help doctors see where to place the stent. Some people have an allergic reaction to the dye, which can also cause kidney problems. Sometimes the hole where the catheter is inserted does not fully heal and close, which can lead to disruption of proper blood flow, according to VascularWeb.
Stent Risks
Blood clots can form around the stent, and if they break off and travel to other parts of the body, these clots can cause a heart attack, stroke, or other problems, according to the NHLBI. This happens to one to two percent of patients. The risk is highest in the first few months after the stent is placed. Patients are put on anti-clotting drugs, like aspirin or clopidogrel, to reduce this risk.
Artery Narrowing
Sometimes the tissue of the artery grows back in and around the stent and the artery begins to narrow and clog again, according to the NHLBI. Called restenosis, this problem can sometimes be avoided by using a stent coated with a drug that prevents the tissue around the stent from growing. This may increase the risk of blood clots, though there is no conclusive evidence that drug-coated stents increase the risk of death or heart attack, according to the NHLBI. Another option is to treat the area around the stent with radiation to prevent restenosis. The radiation is delivered through a tiny wire inserted through a catheter to the area of the stent. Sometimes a second angioplasty or even bypass surgery is required to restore blood flow after restenosis, according to VascularWeb.
Risks of Aortic Stents
Sometimes a stent is used to repair a weakened, bulging aortic artery, called an aneurysm, that is in danger of bursting, according to the NHLBI. When this is done in the abdomen, there is a risk that the artery will rupture or block blood flow. If the flow of blood to the spinal cord is blocked, this can cause paralysis.
Sometimes stents in the aorta, the body's biggest blood vessel, can move. This requires another procedure to put a new stent in the area of the aneurysm.
