Why Does Restenosis Happen (and What Can Be Done About It)?

The best treatment depends on the cause
Illustration of a stent angioplasty in a vein

Good blood flow throughout your body is obviously important. That’s why stenosis, or narrow blood vessels, is a problem. And unfortunately, this problem can happen again after you’ve had a blocked artery reopened. That’s when it becomes restenosis.

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Stent placement helps restore blood flow through previously blocked arteries, but some patients develop restenosis (re-narrowing) over time.

Stephen Ellis, MD, Director of Interventional Cardiology, explains, “There are effective ways to restore blood flow if restenosis occurs, but it’s important to assess the cause and to tailor treatment accordingly.”

Why does restenosis occur?

Despite advances, Dr. Ellis says, “in-stent restenosis still occurs in approximately 3 to 10% of patients within six to nine months, and sometimes afterwards. We have learned that restenosis is a very complex process.”

Some known causes include:
• Stents that are too small or misaligned in the blood vessel.
• Older-generation stents.
• Abundant healing within the stent with scarring.

How does your doctor find out what’s causing restenosis?

Before any treatment for restenosis, your doctor will perform tests to understand what’s causing any problems. Catheterization allows doctors to look inside the artery and to perform tests including:

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  • Intravascular ultrasound that uses sound waves to see inside blood vessels.
  • Optical coherence tomography that uses light to create images.

How will my restenosis be treated?

Different options are available to treat restenosis the first time it happens:

  1. Reopen the stented area. This is especially beneficial if the original stent turned out to be too small. Your doctor can do a repeat balloon angioplasty, which enlarges the opening of the blood vessel by pushing back plaque and scar tissue against blood vessel walls. Cutting balloon angioplasty uses tiny built-in blades that (once deployed) can cut out some of the plaque buildup. Sometimes laser or lithotripsy are required to fully expand the stent if the scar tissue is particularly tough. These types of angioplasty are options for relatively short blockages.
  2. Use a better stent. Earlier generation stents (bare metal or first generation drug-eluting) stents can be covered over with newer drug-eluting stents.
  3. Deliver medicine through balloon angioplasty. Balloon angioplasty itself can deliver a dose of scar-inhibiting medication. This treatment option avoids the placement of yet another stent. Studies are ongoing on this yet-to-be-approved technique.

What happens when you have repeated restenosis?

For some patients, restenosis is a recurring problem. If the blockage has recurred several times or if there are multiple blockages, your doctor may recommend bypass surgery to restore adequate blood flow.

Other options include:

Medicines. Two oral medications may somewhat lessen the risk of restenosis: sirolimus, the drug used on the first generation of drug-eluting stents, and cilostazol, another type of medicine that helps widen blood vessels and reduce clumping of red blood cells. These are typically used in conjunction with balloon or cutting balloon angioplasty.

Though sometimes useful, these drugs aren’t for every patient and they require more study, Dr. Ellis says.

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Brachytherapy. This treatment uses radiation to keep scar tissue from building up again in the stent. Doctors perform brachytherapy at the same time as angioplasty.

After completing angioplasty, the doctor threads another catheter with a “ribbon” of radioactive particles (isotopes) to the blockage, leaves it in place for a few minutes, and then removes the catheter.

If you or someone you know has restenosis

When you face problems resulting from restenosis, it is important to find a center that has experienced doctors who are able to provide you with a broad range of treatment options.

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