- A stent is a small mesh tube that's used to treat narrowed or weakened arteries in the body.
- A stent may be placed in an artery as part of a procedure called angioplasty. Angioplasty restores blood flow through narrowed or blocked arteries. Stents help prevent the arteries from becoming narrowed or blocked again in the months or years after angioplasty.
The illustration shows the placement of a stent in a coronary artery with plaque buildup.
Figure A shows the deflated balloon catheter and closed stent inserted into the narrowed coronary artery. The inset image on figure A shows a cross-section of the artery with the inserted balloon catheter and closed stent. In figure B, the balloon is inflated, expanding the stent and compressing the plaque to restore the size of the artery. Figure C shows normal blood flow restored in the stent-widened artery. The inset image on figure C shows a cross-section of the compressed plaque and stent-widened artery.
- Stents may also placed in a weakened artery to improve blood flow and help prevent the artery from bursting.
- Stents usually are made of metal mesh, but sometimes they're made of fabric. Fabric stents, also called stent grafts, are used in larger arteries.
- Stents can be placed in the coronary arteries, carotid arteries, and the arteries in the kidneys and limbs. Stents also are used to repair aneurysms in the aorta, the major artery that carries oxygen-rich blood from the heart to the body.
- To place a stent, your doctor makes a small opening in a blood vessel in your groin (upper thigh), arm, or neck. Through this opening, a thin, flexible tube called a catheter with a deflated balloon and stent on the end is threaded up to the area of the artery that needs treatment. The balloon is then expanded, which widens the narrowed artery and pushes the stent into place.
- The placement of a stent takes about an hour or more. You may have to stay in the hospital for up to 3 days, depending on which artery is treated.
- To prevent blood clots after having a stent placed, your doctor will likely recommend that you take aspirin and another anticlotting medicine for at least 1 month or up to a year or more, depending on the type of stent you get. It's very important to continue taking these medicines for as long as your doctor recommends.
- Avoid vigorous exercise and heavy lifting for a short time after a stent procedure. Your doctor will let you know when you can go back to your normal activities.
- Angioplasty is a common medical procedure. There's a small risk of serious complications, such as bleeding at the catheter insertion site, damage to the blood vessel where the catheter was inserted, irregular heartbeats, infection, and damage to the kidneys or an allergic reaction due to the dye used during the procedure.
- Another problem after angioplasty is too much tissue growth within the treated portion of the artery. This is called restenosis.
The illustration shows the restenosis of a stent-widened coronary artery. In figure A, the expanded stent compresses plaque, allowing normal blood flow. The inset image on figure A shows a cross-section of the compressed plaque and stent-widened artery. In figure B, over time, tissue grows through and around the stent, causing a partial blockage and abnormal blood flow. The inset image on figure B shows a cross-section of the growth of the tissue around the stent.
- About 1 to 2 percent of people who have a stented artery develop a blood clot at the stent site. The risk of blood clots is greatest during the first few months after the stent is placed in the artery. Taking aspirin and another anti-clotting medicine can lower the risk for blood clots.
How Are Stents Used?
For the Coronary Arteries
Doctors may use stents to treat coronary heart disease (CHD). CHD is a disease in which a waxy substance called plaque builds up inside the coronary arteries. These arteries supply your heart muscle with oxygen-rich blood. When plaque builds up in the arteries, the condition is called atherosclerosis. Plaque narrows the coronary arteries, reducing the flow of oxygen-rich blood to your heart. This can lead to chest pain or discomfort called angina. The buildup of plaque also makes it more likely that blood clots will form in your coronary arteries. If blood clots block a coronary artery, a heart attack will occur.
Doctors may use percutaneous coronary intervention (PCI), also known as coronary angioplasty, and stents to treat CHD. During PCI, a thin, flexible tube with a balloon or other device on the end is threaded through a blood vessel to the narrow or blocked coronary artery. Once in place, the balloon is inflated to compress the plaque against the wall of the artery. This restores blood flow through the artery, which reduces angina and other CHD symptoms. Unless an artery is too small, a stent usually is placed in the treated portion of the artery during PCI. The stent supports the artery's inner wall. It also reduces the chance that the artery will become narrow or blocked again. A stent also can support an artery that was torn or injured during PCI.
Even with a stent, there's about a 10–20 percent chance that an artery will become narrow or blocked again in the first year after PCI. When a stent isn't used, the risk can be as much as 10 times as high. Research has shown that as time goes by, people who have coronary artery stents are in less danger of risks from the surgery but more prone to the risks of chronic diseases, such as type 2 diabetes and renal failure.
For the Carotid Arteries
Doctors also may use stents to treat carotid artery disease. This is a disease in which plaque builds up in the arteries that run along each side of your neck. These arteries, called carotid arteries, supply oxygen-rich blood to your brain. The buildup of plaque in the carotid arteries limits blood flow to your brain and puts you at risk for a stroke. Doctors use stents to help support the carotid arteries after they're widened with PCI. Researchers continue to explore the risks and benefits of carotid artery stenting.
For Other Arteries
Plaque also can narrow other arteries, such as those in the kidneys and limbs. Narrow kidney arteries can affect kidney function and lead to severe high blood pressure. Narrow arteries in the limbs, a condition called peripheral artery disease (P.A.D.), can cause pain and cramping in the affected arm or leg. Severe narrowing can completely cut off blood flow to a limb, which could require surgery. To relieve these problems, doctors may do PCI on a narrow kidney, arm, or leg artery. They often will place a stent in the affected artery during the procedure. The stent helps support the artery and keep it open.
For the Aorta in the Abdomen or Chest
The aorta is a major artery that carries oxygen-rich blood from the left side of the heart to the body. This artery runs through the chest and down into the abdomen. Over time, some areas of the aorta's walls can weaken. These weak areas can cause a bulge in the artery called an aneurysm. An aneurysm in the aorta can burst, leading to serious internal bleeding. When aneurysms occur, they're usually in the abdominal aorta. To help avoid a burst, doctors may place a fabric stent in the weak area of the abdominal aorta. The stent creates a stronger inner lining for the artery. Aneurysms also can develop in the part of the aorta that runs through the chest. Doctors also use stents to treat these aneurysms. How well the stents work over the long term still isn't known.
To Close Off Aortic Tears
Another problem that can occur in the aorta is a tear in its inner wall. If blood is forced into the tear, it will widen. The tear can reduce blood flow to the tissues that the aorta serves. Over time, the tear can block blood flow through the artery or burst. If this happens, it usually occurs in the chest portion of the aorta. Researchers are developing and testing new kinds of stents that will prevent blood from flowing into aortic tears. A stent placed within the torn area of the aorta might help restore normal blood flow and reduce the risk of a burst aorta.
How Are Stents Placed?
Doctors place stents in arteries as part of a procedure called percutaneous coronary intervention (PCI), also known as coronary angioplasty. To place a stent, your doctor will make a small opening in a blood vessel in your groin (upper thigh), arm, or neck.
Through this opening, your doctor will thread a thin, flexible tube called a catheter. The catheter will have a deflated balloon at its tip.
A stent is placed around the deflated balloon. Your doctor will move the tip of the catheter to the narrow section of the artery or to the aneurysm or aortic tear site.
Special x-ray movies will be taken of the tube as it's threaded through your blood vessel. These movies will help your doctor position the catheter.
For Arteries Narrowed by Plaque
Your doctor will use special dye to help show narrow or blocked areas in the artery. He or she will then move the catheter to the area and inflate the balloon. As the balloon inflates, it pushes the plaque against the artery wall. This widens the artery and helps restore blood flow. The fully extended balloon also expands the stent, pushing it into place in the artery. The balloon is deflated and pulled out along with the catheter. The stent remains in your artery. Over time, cells in your artery grow to cover the mesh of the stent. They create an inner layer that looks like the inside of a normal blood vessel.
A very narrow artery, or one that's hard to reach with a catheter, may require more steps to place a stent. At first, your doctor may use a small balloon to expand the artery. He or she then removes the balloon. The small balloon is replaced with a larger balloon that has a collapsed stent around it. At this point, your doctor can follow the standard process of compressing the plaque and placing the stent. Doctors use a special filter device when doing PCI and stent placement on the carotid arteries. The filter helps keep blood clots and loose pieces of plaque from traveling to the brain during the procedure.
For Aortic Aneurysms
The procedure to place a stent in an artery with an aneurysm is very similar to the one described above. However, the stent used to treat an aneurysm is different. It's made out of pleated fabric instead of metal mesh, and it often has one or more tiny hooks.
The stent is expanded to fit tight against the artery wall. The hooks latch on to the wall of the artery, holding the stent in place.
The stent creates a new inner lining for that portion of the artery. Over time, cells in the artery grow to cover the fabric. They create an inner layer that looks like the inside of a normal blood vessel.
What To Expect Before a Stent Procedure
Most stent procedures require an overnight stay in the hospital and someone to take you home. Discuss with your doctor:
- When to stop eating and drinking before coming to the hospital
- What medicines you should or shouldn't take on the day of the procedure
- When to come to the hospital and where to go
If you have diabetes, kidney disease, or other conditions, talk with your doctor about whether you need to take any extra steps during or after the procedure to avoid complications.Before the procedure, your doctor may talk with you about medicines you'll probably need to take after the stent is placed. These medicines help prevent blood clots from forming.It's important that you know how long you should take these medicines and why they're important.
What To Expect During a Stent Procedure
For Arteries Narrowed by Plaque
This procedure usually takes about an hour. It could take longer if stents are inserted into more than one artery during the procedure.Before the procedure starts, you'll get medicine to help you relax. You'll be on your back and awake during the procedure so you can follow the doctor's instructions.The area where the catheter is inserted will be numbed, and you won't feel the doctor threading the catheter, balloon, or stent inside the artery. You may feel some pain when the balloon is expanded to push the stent into place.
For Aortic Aneurysms
This procedure takes a few hours. It usually requires a 2- to 3-day stay in the hospital.Before the procedure, you'll be given medicine to help you relax. If a stent is placed in the abdominal aorta, your doctor may give medicine to numb the area, but you'll be awake during the procedure.If a stent is placed in the chest portion of the aorta, your doctor will likely give you medicine to make you sleep through the procedure.Once you're numbed or asleep, your doctor will make a small cut in your groin (upper thigh). He or she will insert a catheter into the blood vessel through this cut.Sometimes, two cuts (one in the groin area of each leg) are needed to place fabric stents that come in two parts. You will not feel the doctor threading the catheter, balloon, or stent into the artery.
What To Expect After a Stent Procedure
After either type of stent procedure (for arteries narrowed by plaque or aortic aneurysms), the catheter will be removed and the tube insertion site will be bandaged.A small sandbag or other type of weight may be put on top of the bandage to apply pressure and help prevent bleeding. You'll recover in a special care area where your movement will be limited.While you're in recovery, a nurse will check your heart rate and blood pressure regularly. The nurse also will see whether there's any bleeding from the insertion site. Eventually, a small bruise and sometimes a small, hard "knot" will appear at the insertion site. This area may feel sore or tender for about a week.You should let your doctor know if:
- You have a constant or large amount of bleeding at the site that can't be stopped with a small bandage.
- You have any unusual pain, swelling, redness, or other signs of infection at or near the insertion site.
Common Precautions After a Stent Procedure
Blood Clotting Precautions
After a stent procedure, your doctor will likely recommend that you take aspirin and another anticlotting medicine. These medicines help prevent blood clots from forming in the stent. A blood clot can lead to heart attack, stroke, or other serious problems.If you have a metal stent, your doctor will likely recommend aspirin and another anticlotting medicine for at least 1 month. If your stent is coated with medicine, your doctor may recommend aspirin and another anticlotting medicine for 12 months or more. Your doctor will work with you to determine the best course of treatment.The risk of developing a blood clot significantly increases if you stop taking the anticlotting medicine too early. It's important to take these medicines for as long as your doctor recommends. He or she may recommend lifelong treatment with aspirin.If you're considering surgery for some other reason while you're on these medicines, talk to your doctor about whether it can wait until after you've stopped the medicine. Anticlotting medicines may increase the risk of bleeding.In addition to an increased risk of bleeding, anticlotting medicines can cause other side effects, such as an allergic rash. Talk to your doctor about how to reduce the risk of these side effects.
You should avoid vigorous exercise and heavy lifting for a short time after the stent procedure. Your doctor will let you know when you can go back to your normal activities.If you have a metal stent, you shouldn't have a magnetic resonance imaging (MRI) test within the first couple of months after the procedure. Metal detectors used in airports and other screening areas don't affect stents. Your stent shouldn't cause metal detectors to go off.If you have an aortic fabric stent, your doctor will probably recommend that you have followup imaging tests (for example, chest x ray) within the first year of having the procedure. After the first year, he or she may recommend yearly imaging tests.
What Are the Risks of Having a Stent?
Risks Related to Percutaneous Coronary Intervention (Coronary Angioplasty)
Percutaneous coronary intervention (PCI), the procedure used to place stents, is a medical procedure that is commonly known as coronary angioplasty. PCI carries a small risk of serious complications, such as:
- Bleeding from the site where the catheter was inserted into the skin
- Damage to the blood vessel from the catheter
- Arrhythmias (irregular heartbeats)
- Damage to the kidneys caused by the dye used during the procedure
- An allergic reaction to the dye used during the procedure
Another problem that can occur after PCI is too much tissue growth within the treated portion of the artery. This can cause the artery to become narrow or blocked again. When this happens, it's called restenosis (RE-sten-no-sis).
Using drug-eluting stents can help prevent this problem. These stents are coated with medicine to stop excess tissue growth.
Treating the tissue around the stent with radiation also can delay tissue growth. For this procedure, the doctor threads a wire through a catheter to the stent. The wire releases radiation and stops cells around the stent from growing and blocking the artery.
Risks Related to Stents
About 1 to 2 percent of people who have a stented artery develop a blood clot at the stent site. Blood clots can cause heart attack, stroke, or other serious problems.
The risk of blood clots is greatest during the first few months after the stent is placed in the artery. Your doctor will likely recommend that you take aspirin and another anticlotting medicine, such as clopidogrel, for at least 1 month or up to a year or more after having a stent procedure. These medicines help prevent blood clots.The length of time you need to take anticlotting medicines depends on the type of stent you get. Your doctor may recommend lifelong treatment with aspirin.Stents coated with medicine, which often are used to keep clogged heart arteries open, may increase your risk for potentially dangerous blood clots. However, no conclusive evidence shows that these stents increase the chances of having a heart attack or dying, if used as recommended.
Risks Related to Aortic Stents in the Abdomen
Although rare, a few serious complications can occur when surgery or a fabric stent is used to repair an aneurysm in the abdominal region of the aorta. These complications include:
- A burst artery (aneurysm rupture).
- Blocked blood flow to the stomach or lower body.
- Paralysis in the legs due to interruption of blood flow to the spinal cord. This complication is very rare.
Another possible complication is the fabric stent moving further down the aorta. This sometimes happens years after the stent is first placed. Such stent movement may require a doctor to place another fabric stent in the area of the aneurysm.
Reference: The National Heart, Blood, and Lung Institute.
Last updated April 28, 2017