In-Stent Restenosis: Causes, Symptoms, and Advanced Treatment Options
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
In-stent restenosis (ISR) is a narrowing that returns in the part of a coronary artery previously treated with a stent, usually within 3 to 6 months. With today's drug-eluting stents it affects 5% to 10% of people; rates of up to 1 in 4 were seen with older bare-metal stents. The main symptom is angina, though many have none. [1]
What the research says
Drug-coated balloons beat plain balloons for ISR. A meta-analysis of 6 randomized trials (1,171 patients) found that drug-coated balloons cut the odds of target lesion revascularization (OR 0.22, 95% CI 0.10 to 0.46), restenosis (OR 0.13, 95% CI 0.06 to 0.27), and major adverse cardiac events (OR 0.20, 95% CI 0.12 to 0.37) compared with plain balloon angioplasty. Reductions in death and heart attack were not statistically significant. (Shaikh et al., Am J Cardiol, 2024)
Drug-coated balloons and drug-eluting stents had similar overall results for ISR, with more repeat procedures after balloons. Across 10 randomized trials (1,977 patients), major adverse cardiac events occurred in 15.57% with drug-coated balloons and 14.13% with drug-eluting stents (OR 1.04, 95% CI 0.87 to 1.44), but repeat target lesion revascularization was higher with balloons (OR 1.54, 95% CI 1.2 to 1.99). (Abdelaziz et al., J Cardiothorac Surg, 2024)
The balloon's drug may matter less than expected. A meta-analysis of 1,861 patients treated with paclitaxel-coated versus sirolimus-coated balloons found no significant difference in target lesion failure at 9 to 12 months (OR 1.01, 95% CI 0.75 to 1.35). (Shin et al., Catheter Cardiovasc Interv, 2024)
What Is In-Stent Restenosis?
Stenosis is the medical term for the narrowing of a blood vessel. To treat coronary artery disease (CAD), providers often perform angioplasty, a procedure in which a balloon at the tip of a catheter opens the blocked artery and a stent, a tiny wire mesh tube, is often placed to keep it open. In-stent restenosis (ISR) occurs when the treated artery narrows again at the site of the stent. [1]
After a stent is placed, tissue grows over it to form a new lining that helps blood flow smoothly and lowers the chance of a clot. Some scar tissue under this lining is not unusual. But when there is too much, the lining becomes too thick and slows blood flow to the heart muscle again. [1]
Recognizing the Signs and Symptoms
Many people with in-stent restenosis have no symptoms at all, which is why regular checkups after stenting are important. When symptoms do occur, they are often similar to those of CAD. [1]
Common physical symptoms
The most common symptom is angina, a chest discomfort or pressure that physical activity or exertion can bring on. Other symptoms include shortness of breath, fatigue and weakness, heart palpitations, dizziness or lightheadedness, nausea, and cold sweats or clamminess. [1]
Associated pain areas
Discomfort is not always limited to the chest and can show up as shoulder or arm pain. If you have had angioplasty and stenting and notice chest discomfort, arm or shoulder pain, cold sweats, shortness of breath, or unexplained fatigue or weakness, call your provider. Call emergency services if you think you are having a heart attack. [1]
Symptom category | Common signs |
Primary sign | Angina (chest pain or pressure, often during exertion) |
Respiratory | Shortness of breath |
Systemic | Fatigue, weakness, dizziness, nausea, cold sweats |
Radiating pain | Shoulder or arm pain |
Risk Factors and Prevention
Anyone who has angioplasty and stenting for CAD can develop ISR, but some conditions raise the risk. [1]
Clinical risk factors
Risk is higher in people with high cholesterol, kidney disease, uncontrolled diabetes, or uncontrolled high blood pressure (hypertension). [1]
Lifestyle and technology
Smoking is another risk factor. ISR is also less likely with drug-eluting stents, which have a thin coating of medication that helps prevent scar formation inside the stent, unlike bare-metal stents. Concerns in the early 2000s that drug-eluting stents raised the risk of heart attack have eased, because newer versions are safe and effective. [1]
Diagnostic Testing and Treatment Options
Because ISR does not always cause symptoms, regular checkups matter. If you have symptoms, your provider may recommend tests to look for a narrowing, and treatment depends on how severe it is. [1]
Diagnostic tests
Tests can include an exercise stress test to see how well your heart pumps blood during exertion and cardiac catheterization to check for blockages. A coronary computed tomography angiogram (CCTA) gives moving 3D images of blood flow to the heart, intravascular ultrasound (IVUS) produces detailed images of the inside of the arteries, and fractional flow reserve (FFR) measures blood pressure inside the arteries. [1]
Treatment pathways
Your provider may increase or add medicines to help with symptoms. Other treatments include repeat angioplasty, which sometimes requires another stent, and heart bypass surgery (coronary artery bypass grafting, or CABG), which uses a transplanted artery to send blood around the blockage. Vascular brachytherapy uses radiation to treat a blocked artery. [1] Drug-coated balloons, which deliver medication to the artery wall during angioplasty, are another option that has been studied for ISR. (Shaikh et al., Am J Cardiol, 2024)
Conclusion and Heart Health
People who develop ISR may be more prone to serious heart problems such as unstable angina, acute coronary syndrome, and heart attack, but newer stents and better stenting techniques are lowering these risks. [1] Protecting your heart means following your provider's advice: manage blood pressure and cholesterol, eat a heart-healthy diet low in sodium and in saturated and trans fats, keep a healthy weight and stay active, manage diabetes, drink alcohol in moderation, and quit smoking if you smoke. [1] If you have a stent and have chest discomfort, contact your cardiologist right away.
Learn more. For more evidence-based health guides, visit Rinnit.com.
Frequently Asked Questions
How soon after stenting does restenosis usually occur?
In-stent restenosis usually develops within the first 3 to 12 months after the procedure, but with drug-eluting stents it can also appear later, even years afterward, so regular checkups remain important. [1]
What is the difference between stenosis and restenosis?
Stenosis is the narrowing of a blood vessel. Restenosis is the narrowing of that same vessel again after it has been treated and opened. [1]
Are all stents at risk for restenosis?
Anyone who gets a stent can develop ISR, but drug-eluting stents carry a lower risk than bare-metal stents. [1]
Can I have ISR without feeling any pain?
Yes. Many people with in-stent restenosis have no symptoms, which is why regular checkups are important. [1]
Is ISR the same as a blood clot?
No. ISR comes from excess scar tissue growing under the stent lining, while a blood clot is a sudden blockage of congealed blood. [1]
What is a drug-eluting stent?
A drug-eluting stent is a stent with a thin coating of medication that helps prevent scar formation inside the stent. [1]
Does smoking affect my stent?
Yes. Smoking is a risk factor for in-stent restenosis and for coronary artery disease in general. [1]
What is vascular brachytherapy?
Vascular brachytherapy is radiation therapy used to treat a blocked artery, also called coronary brachytherapy. [1]
Can exercise cause restenosis?
No, but exercise can bring on symptoms such as angina if restenosis is already present. [1]
Is repeat angioplasty an option for ISR?
Yes. Repeat angioplasty, sometimes with another stent, is one of the main treatments. Your cardiologist will explain the risks and benefits for your situation. [1]
What is fractional flow reserve (FFR)?
FFR is a test that measures blood pressure inside the arteries to help show how much a blockage limits blood flow. [1]
Can a heart-healthy diet prevent ISR?
A diet low in sodium and in saturated and trans fats helps control high blood pressure and cholesterol, which are risk factors, but it cannot guarantee that ISR will not develop. [1]
What is IVUS?
Intravascular ultrasound (IVUS) is a test that produces detailed images of the inside of the arteries. [1]
Is ISR life-threatening?
ISR can be. People with ISR may be more prone to unstable angina, acute coronary syndrome, and heart attack, which is why symptoms should be checked promptly. [1]
How often should I see my doctor after getting a stent?
Follow the schedule your cardiologist gives you. Regular checkups are important because ISR does not always cause symptoms. [1]
Related Reading
Coronary Brachytherapy: Procedure, Benefits and Risks explains coronary brachytherapy.
Intravascular Ultrasound (IVUS): Seeing Inside Arteries to Guide Stents explains the catheter ultrasound that images arteries from the inside.
References
Cleveland Clinic. In-Stent Restenosis. Cleveland Clinic. Last updated July 20, 2022. https://my.clevelandclinic.org/health/diseases/17132-cad-in-stent-restenosis
Shaikh S, et al. Meta-Analysis Comparing Drug-Coated Balloon Versus Plain Old Balloon Angioplasty for In-Stent Restenosis of Coronary Arteries. Am J Cardiol. 2024;229:22-27. PMID 39029724. https://doi.org/10.1016/j.amjcard.2024.07.015
Abdelaziz A, et al. Drug-coated balloons versus drug-eluting stents in patients with in-stent restenosis: An updated meta-analysis with trial sequential analysis. J Cardiothorac Surg. 2024;19(1):624. PMID 39506808. https://doi.org/10.1186/s13019-024-03046-6
Shin D, et al. Paclitaxel-coated versus sirolimus-coated balloon angioplasty for coronary artery disease: A systematic review and meta-analysis. Catheter Cardiovasc Interv. 2024;104(3):425-436. PMID 39044661. https://doi.org/10.1002/ccd.31154
Medical disclaimer
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
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