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A coronary stent is an artificial support device used in the coronary artery to keep the vessel open.
The coronary stent is a relatively new tool used to keep coronary arteries expanded, usually following a balloon angioplasty. Balloon angioplasty is used in patients with coronary artery disease. In this disease, the blood vessels on the heart become narrow. When this happens, the oxygen supply is reduced to the heart muscle. The primary cause of coronary artery disease is fat deposits blocking the arteries (atherosclerosis). In many cases, balloon angioplasty is unsuccessful and the vessel closes after the procedure (restenosis). By forming a rigid support, the stent can prevent restenosis and reduce the need for coronary bypass surgery. The stent is usually a stainless steel mesh tube. Since the stent will be placed inside an artery, the device comes in various sizes to match the size of the artery.
Any foreign object in the body, like a stent, will increase the risk of thrombosis. Anticlotting medication is given to prevent this complication.
Coronary stenting usually follows balloon angioplasty, which requires inserting a balloon catheter into the femoral artery in the upper thigh. When this catheter is positioned at the location of the blockage in the coronary artery, it is slowly inflated to widen that artery, and is then removed. The stent catheter is then threaded into the artery and the stent is placed around a deflated balloon. When this is correctly positioned in the coronary artery, the balloon is inflated, expanding the stent against the walls of the coronary artery. The balloon catheter is removed, leaving the stent in place to hold the coronary artery open. A cardiac angiography will follow to insure that the stent is keeping the artery open.
Balloon angioplasty and coronary stenting are performed to relieve the symptoms of coronary artery disease. By the time coronary artery disease progresses and requires balloon angioplasty, there is no alternative to balloon angioplasty other than coronary bypass surgery. Coronary bypass surgery carries greater risks. However, since coronary artery disease can be related to high fat diets, smoking, and lack of exercise, changes in lifestyle may reduce the risk of developing the disease. Various medications for cholesterol, high blood pressure, and diabetes also can help treat or prevent coronary artery disease.
Before the stent is inserted, the patient will probably be instructed to take aspirin for several days. Aspirin can help decrease the possibility of blood clots forming at the stent. Because anesthesia will be used during the procedure, the patient should not eat or drink after midnight of the previous day.
Following the procedure, blood thinners (anticoagulants) will be given through a needle in a vein for about 24 hours. The patient should remain flat and still for awhile to allow the femoral artery to heal from the insertion of the catheter. Medication to control blood clotting should be taken after the patient is discharged from the hospital. A special diet may also be recommended that is low in vitamin K and cholesterol. With time, the patient should begin light exercise, like walking. It is important that no magnetic resonance imaging (MRI) tests are given for six months because the magnetic field may move the stent.
Although coronary stents greatly reduce the risk of restenosis following balloon angioplasty, there is still some risk that the stented artery may close. Thrombosis, bleeding, and artery damage are also risks.
American Heart Association. 7320 Greenville Ave, Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.
Balloon angioplasty — The use of a balloon attached to a catheter to widen an artery that has become narrowed. As the balloon is inflated, it opens the artery.
Cardiac angiography — A procedure used to visualize blood vessels of the heart. A catheter is used to inject a dye into the vessels; the vessels can then be seen by x ray.
Catheter — A long thin flexible tube that can be inserted into the body; in this case, it is threaded to the heart.
Restenosis — The narrowing of a blood vessel after it has been opened, usually by balloon angioplasty.
Thrombosis — The development of a blood clot in the vessels. This thrombosis may clog a blood vessel and stop the flow of blood.