Stents and Blood Clots

Medically reviewed by Alana Biggers, MD on December 12, 2017Written by Kristeen Cherney on September 26, 2014

What is a stent?

A stent is a mesh tube placed in a blood vessel. It’s used to widen your vessel and increase blood flow. Stents are commonly used in the arteries of the heart, also known as the coronary arteries.

Stents are used during percutaneous coronary intervention (PCI). PCI is a procedure conducted to prevent restenosis, which is the repeated closure of arteries that are dangerously narrow.

During PCI, these narrow arteries are mechanically opened. This happens when they appear to be in danger of closing completely. The procedure to open the arteries is also called an angioplasty. Angioplasty is often accomplished by using tiny balloons that are inflated within the narrowed arteries.

Connection between stents and blood clots

Clogged arteries are a result of plaque, which is the buildup of fats, cholesterol, and calcium. The fatty deposits harden over time, which can make it difficult for blood to pass through those sections of the arteries. After the plaque builds up, areas of your heart muscle receive less blood, less oxygen, and fewer nutrients. As the plaque buildup increases, these areas can become prone to the development of blood clots.

If a blood clot completely blocks the flow of blood, then all the heart muscle beyond the clot are starved of oxygen and a heart attack can occur.

Stents are used to help the previously blocked arteries remain open after an angioplasty. This allows blood to continue to flow throughout the coronary arteries. Allowing blood to flow freely helps prevent heart attacks.

However, due to the delicate nature of your heart and arteries, stent placements aren’t free of risks. The procedure comes with some potential problems, including blood clots and vessel rupture.

Stent procedure

A PCI is ordered when the arteries in the heart become clogged. During a typical stent procedure, the following occurs:

  • Your surgeon inserts a catheter, or tube, with a small balloon near the tip into the artery.
  • Under X-ray guidance, your surgeon gently places the catheter into the artery so that the balloon section is within the area of blockage.
  • Your surgeon then inflates the balloon, usually with a saltwater solution or X-ray dye. This opens the blockage and helps reestablish proper blood flow.
  • After your artery is widened to an acceptable width your surgeon removes the catheter.

In a general PCI, the coronary arteries are at risk of closing again over time. Stents are used to keep the artery open. According to the American Heart Association (AHA), about one-third of people who’ve had angioplasty without a stent see their arteries get narrower after their procedure.

The stent procedure is similar to a PCI that uses only a balloon. The difference is that the stent is placed over the catheter. Once the catheter is in place with the stent, it expands along with the balloon. As the stent expands, it becomes locked in place permanently. Most stents are made of a mesh material to ease the process. For larger arteries, fabric stents may be used.

Purpose of a stent procedure

The benefit of using a stent is that it may provide consistent blood flow to your heart so that you have fewer related symptoms, such as chest pain or angina. Angina occurs when your heart muscle needs more oxygen than the narrowed artery can provide.

You may be a candidate for a stent as part of a PCI if you have one or more of the following related conditions:

According to The Lancet, PCI isn’t recommended for people with stable angina.

In some extreme cases, stents can’t be used at all. Some of the main reasons your doctor will forego PCI and stents include:

  • your arteries are too narrow
  • you have numerous diseased or weakened blood vessels
  • you have severe disease in multiple vessels
  • you have a history of diabetes

After the procedure

Though stents are generally effective, there’s still a risk that your arteries may close. Blood clots can occur, and action must be taken to prevent a heart attack. Some people require coronary artery bypass graft surgery (CABG) at this point. CABG involves taking blood vessels from another area of the body or a synthetic blood vessel replacement to bypass blood around the blocked artery.

You can decrease your risk for blood clots after stent placement by:

Risks

Stents are not completely foolproof. The National Heart, Lung, and Blood Institute estimates that people with stents may still experience a 10 to 20 percent chance of blocked arteries. Also, as with other procedures, stents come with possible risks.

Though stents are used to treat coronary artery disease (CAD) and its complications, including clots, stents themselves can also lead to clots.

The presence of a foreign body, such as a stent, in constant contact with the blood may lead to clotting in some people. About 1 to 2 percent of people who receive stents develop blood clots in the stent location.

Outlook

Most modern stents are drug-covered stents, which are coated with medications to prevent clots. In some cases, traditional bare metal stents are still used. These aren’t coated with drugs that prevent clots.

Your doctor will also prescribe anticlotting drugs to take after surgery to prevent blood clots. The most commonly used medications are clopidogrel (Plavix) and aspirin (Bayer). Regular blood tests are necessary, especially when taking clopidogrel. If you have drug-covered stents, you have to take anticlotting medications for at least six months to a year. With bare metal stents, you have to take the medications for at least one month.

An aneurysm is a rare but serious and life-threatening risk. It’s important to talk to your doctor about your specific condition and personal risk factors that may increase your risk for blood clots.

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