A stent is a small tube that a doctor places in an artery or duct to help keep it open and restore the flow of body fluids to the area. Stents help relieve blockages and treat narrow or weakened arteries. Doctors may also insert stents in other areas of the body to support the blood vessels in the brain or the tubes that carry urine and bile.
A stent is generally a mesh-like metal tube, although cloth stents are also available. Sometimes doctors will use drug-coated soluble stents as a temporary solution.
One of the most common uses for a stent is to open a blood vessel that has a plaque blockage. Plaque is a build-up of cholesterol, fat, and other substances found in the blood. When this plaque builds up in the bloodstream, it sticks to the walls of the arteries. Over time, this buildup narrows the arteries, limiting the amount of fresh blood that can reach the body.
A buildup of plaque in the arteries is a cause of coronary heart disease. Over time, people with narrowed arteries may begin to notice warning symptoms, such as chest pain. If people with the condition go untreated, they may be at higher risk for complications, such as a heart attack or stroke.
If the artery is at risk of collapsing or becoming blocked again, doctors may recommend inserting a stent to keep it open. Doctors place a stent in an artery in a procedure known as percutaneous coronary intervention (PCI) or stent angioplasty. During PCI, doctors will insert a catheter into the artery. The catheter has a small balloon with a stent around it at one end.
When the catheter reaches the point of obstruction, the doctor will inflate the balloon. When the balloon inflates, the stent expands and locks in place. The doctor will then remove the catheter, leaving the stent in place to keep the artery open.
A doctor will decide whether or not to insert a stent based on a number of factors, such as the size of the artery and where the blockage occurs. Doctors can also use stents to:
- Blood vessels in the brain or aorta that are at risk for aneurysm
- Bronchi in the lungs that are at risk of collapse
- Ureters, which carry urine from the kidneys to the bladder.
- Bile ducts, which carry bile between organs and the small intestine.
PCI carries a small risk of complications, including:
- Bleeding from the catheter insertion site
- An infection
- An allergic reaction
- Damage to the artery from catheter insertion
- Kidney damage
- Irregular heartbeat
In some cases, restenosis can occur. Restenosis is when too much tissue grows around the stent. This could narrow or block the artery again. Doctors may recommend forms of radiation therapy or choose to insert a stent coated with drugs to slow tissue growth. People at risk for complications include:
- Older adults
- People with heart failure during the procedure
- People with extensive heart disease and multiple blockages in the arteries
- People with chronic kidney disease
A stent can cause blood to clot, which can increase the risk of heart attack or stroke. The National Heart, Lung, and Blood Institute states that approximately 1 to 2 percent of people who have stented arteries develop a blood clot at the stent site.
Doctors generally prescribe one or more medications to prevent clotting. Blood thinning medications can carry their own risks and can cause irritating side effects, such as rashes.
In rare cases, a person’s body may reject the stent, or they may have an allergic reaction to the material in the stent. Anyone with a known reaction to metals should talk to their doctor about alternatives.