A stent is a small, mesh tube designed to open and support narrowed or blocked arteries, restoring blood flow and alleviating symptoms. While effective, the treated artery can sometimes narrow again, even with the stent in place. This re-narrowing, known as restenosis, can lead to a return of symptoms and may require further medical intervention.
Understanding Stent Restenosis
Stent restenosis refers to the re-narrowing of an artery after a stent has been implanted. This results from the body’s natural healing response to the stent’s presence. It involves the excessive growth of smooth muscle cells within the stent, forming scar tissue (neointimal hyperplasia). This tissue growth reduces the stent’s inner diameter, impeding blood flow.
Bare-metal stents (BMS) historically had higher restenosis rates (17-41%). Drug-eluting stents (DES) significantly reduced these rates to below 10%. DES are coated with medications that inhibit smooth muscle cell overgrowth, preventing the artery from re-narrowing. Despite these advancements, restenosis can still occur in approximately 10% of percutaneous coronary interventions.
Recognizing the Signs
When stent restenosis occurs, symptoms often mirror those that led to the initial stent placement. Individuals might notice the return of chest pain (angina), which can manifest as pressure, squeezing, or fullness in the chest. Shortness of breath, particularly during physical activity or at rest, is another common indicator. Fatigue can also be present.
Discomfort might radiate to the arm, shoulder, back, neck, jaw, or stomach. These symptoms can emerge gradually or suddenly, depending on the speed and degree of re-narrowing. Any reappearance of these signs warrants prompt medical evaluation.
Diagnosis and Treatment Approaches
Diagnosing stent restenosis involves tests to assess blood flow and arterial patency. Coronary angiography is often the most definitive method, providing detailed images of the coronary arteries and the stent, clearly showing any re-narrowing. Other diagnostic tools include stress tests, which evaluate heart function under exertion, and echocardiograms, which use sound waves to create images of the heart’s structure and blood flow. These tests help determine the location and severity of the re-narrowing.
Treatment for restenosis aims to reopen the affected artery and maintain blood flow. One common approach is repeat angioplasty, using a balloon catheter to expand the narrowed segment within the stent. Often, this involves placing another stent, frequently a drug-eluting stent, especially if the initial stent was bare-metal, to reduce recurrence.
In more complex cases, coronary artery bypass grafting (CABG) surgery may be considered, which reroutes blood flow around the blocked artery using a healthy blood vessel. Medications are also prescribed to manage symptoms and help prevent further cardiovascular events.
Minimizing the Risk
Minimizing the risk of stent restenosis involves managing health conditions and adopting a heart-healthy lifestyle. Controlling blood pressure and cholesterol, often through medication and dietary adjustments, helps reduce arterial disease progression. For individuals with diabetes, maintaining stable blood sugar is important, as diabetes can increase restenosis risk in both bare-metal and drug-eluting stents.
Quitting smoking is important, as tobacco damages blood vessels and promotes plaque buildup. Regular physical activity and maintaining a healthy weight also contribute to cardiovascular health and improved blood flow. Adhering to prescribed medications, such as antiplatelet drugs like aspirin and clopidogrel, is important to prevent blood clot formation within the stent. Drug-eluting stents also play a role in prevention, as their medication coating lowers the chance of re-narrowing compared to bare-metal stents.