Stents for Arteries in the Heart
With age and some health conditions, the inside openings of the coronary arteries (arteries of the heart) tend to narrow due to deposits of a fatty substance called plaque. High cholesterol, diabetes, and smoking can cause the arteries to narrow. This narrowing of the coronary arteries can cause angina (chest pain) or lead to heart attack.
During angioplasty, doctors use an expanding balloon inside the coronary artery to compress the plaque and widen the passageway. The result is improved blood flow to the heart and a decreased chance of heart attack.
Unless the coronary artery is too small, doctors usually place a stent in the treated portion of the coronary artery during angioplasty. The stent supports the inner artery wall and reduces the chance of the artery closing up again. A stent also can keep an artery open that was torn or injured during angioplasty.
When stents are placed in coronary arteries, there's a 1 in 5 chance that the arteries will close in the first 6 months after angioplasty. When stents aren't used, the risk of the arteries closing can be twice as high.
Stents for the Carotid Arteries in the Neck
Both the right and left sides of your neck have blood vessels called carotid arteries. These arteries carry blood from the heart to the brain. Carotid arteries can become narrowed by plaque. These plaque deposits limit blood flow to the brain and increase your risk for stroke. Your chance of developing plaque in your carotid arteries increases with age, and may increase if you smoke.
Carotid angioplasty and stenting uses stents to help keep the carotid arteries fully open after they're widened with angioplasty. Not all hospitals offer this procedure. How effective it is long term is still not known. Discuss your options with your cardiologist.
Stents for Other Arteries
The arteries in the kidneys also can become narrowed. This reduces blood flow to the kidneys, which can affect their ability to control blood pressure. This can cause severe high blood pressure.
The arteries in the arms and legs also can narrow with plaque over time. This narrowing can cause pain and cramping in the affected limbs. If the narrowing is severe, it can completely cut off the blood flow to a limb, which could require surgical treatment.
To relieve these problems, cardiologists may perform angioplasty on the narrowed kidney, arm, or leg arteries. This procedure often is followed by placing a stent in the treated artery. The stent helps keep the artery fully open.
Restenosis of an artery
Another common problem after angioplasty is too much tissue growth within the treated portion of the artery. This can cause the artery to narrow or close again, which is called restenosis. This problem is often avoided with the use of newer stents coated with medicines that help prevent too much tissue growth. Treating the tissue around the stent with radiation also can prevent tissue growth. For this procedure, the doctor puts a wire through a catheter to where the stent is placed. The wire releases radiation and stops cells around the stent from growing and blocking the artery.
Restenosis of a Stent-Widened Coronary Artery
The illustration shows the restenosis of a stent-widened coronary artery. The coronary artery is located on the surface of the heart. 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, the plaque 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 plaque around the stent.