In people who have coronary artery disease, the arteries that supply blood to the heart muscle get clogged with fatty deposits called plaques. These plaques can reduce the flow of blood to the heart muscle, which can in turn cause chest pain or discomfort, especially during exertion. There are two main types of treatment for people with this symptom, whose medical term is "angina pectoris": medical therapy (medications) and interventional treatment (procedures to open or bypass narrowed coronary arteries). The goals of these treatments are to improve a person's quality of life and to alleviate symptoms such as angina. In some people, medications may also delay or stop the progression of the disease and thereby prolong life.
This topic discusses drug eluting stent placement, also called "percutaneous coronary intervention.Drug-eluting stent is coated with time-release medicine. That medication is gradually released into your blood vessel to prevent it from becoming blocked again.
Preparing for stent placement — Blood tests and an electrocardiogram are usually performed before stenting. These tests help to ensure that other potential medical problems are identified and managed prior to the procedure.
The patient is given a sedative and may be given a pain medication before the procedure. Most people do not remember the procedure as a result of these medications. A tiny catheter is inserted into an artery in the leg (the femoral artery) or in the wrist (the radial artery). The catheter is guided through blood vessels to the heart. The coronary arteries are viewed by injecting a dye (contrast) through the catheter, using an x-ray device to record a detailed image of the coronary arteries.
Based upon the results of this test, the doctor sometimes proceeds immediately with stent placement if it appears reasonable to do so. "Reasonable" is determined both by the nature of the blockage and by the patient's wishes, which are usually discussed before the catheterization.
In some cases, stenting can be performed immediately following the catheterization.
In other cases, treatment with medications is continued OR open heart surgery with bypass may be recommended.
What does the procedure involve?
A surgeon can insert a stent into your coronary arteries using a coronary angioplasty procedure. For this procedure, you will probably only need a local anesthetic. It may take 30 minutes to several hours to complete.
To begin, your surgeon will make a small incision in your groin or arm. They will insert a small catheter with a balloon and stent on the tip into the incision. Using special dyes and sophisticated imaging techniques, they will guide the catheter through your body and into your narrowed coronary artery. Then they will inflate the balloon to widen your artery and push plaque buildup aside. As it inflates, the balloon will expand the stent to hold your artery open. Next, your surgeon will remove the balloon and catheter, while leaving the stent behind.
If your surgeon inserts a drug-eluting stent, it will release medication directly into your artery. The medication will help prevent scar tissue from forming within the stent and narrowing your blood vessel again. You may also need to take additional medications, including blood thinners, after your procedure. As you recover, your artery will begin to heal around the stent. This will give it added strength.
Why do I need stenting? — Chest pain that is a consequence of decreased oxygen-rich blood to a portion of the heart muscle is called “angina pectoris” (often referred to as just "angina"). Angina is a signal that the heart muscle is not getting sufficient blood flow, specifically sufficient oxygen. Lack of oxygen is termed ischemia. Blood flow is most often reduced by coronary artery disease, which causes a narrowing of the arteries that carry blood to the heart muscle. Narrowing in the coronary arteries occurs as a result of calcium and fatty deposits, called plaques.
A person with narrowed arteries may develop angina during activity, exercise, or any other physical or mental stress that increases the heart's demand for blood. Angina can be "stable" or "unstable." Angina is unstable when there is a change in the usual pattern, such as an increase in frequency, severity, duration, or precipitating cause. Unstable angina may be associated with damage to the heart muscle (or heart attack). The term "acute coronary syndrome" refers to people with unstable angina or a heart attack; these conditions require immediate evaluation in a hospital. In severe cases, heart attack can lead to heart failure or sudden cardiac death.
Stent candidates — Stenting may be recommended in addition to medical therapy for two groups of people with stable angina:
People who have persistent and intolerable symptoms despite adequate medical treatment.
People who have specific patterns of arterial narrowing and a high risk of either a heart attack or death.
The usefulness of stenting depends upon the severity of arterial narrowing. Stenting is often recommended when arterial narrowing is moderate to severe or when only one or two coronary arteries are severely narrowed. People with diabetes appear to have greater benefit from bypass surgery, especially if there are two or three vessels involved, a large amount of the heart muscle is in jeopardy, or left ventricular function is depressed.
People who have extensive coronary heart disease, including a large number of narrowed coronary arteries or narrowing of the left main coronary artery and poor pumping function of their left ventricle (lower heart chamber), tend to live longer when they have coronary artery bypass surgery rather than medical treatment. For some patients with blockages in more than one artery, physicians might recommend using both stenting and CABG (sequentially) in order to achieve the best result.
What are the benefits of drug eluting stents?
Drug-eluting coronary stents can help prevent plaque buildup, promote good blood flow to your heart, and relieve chest pain. They may also lower your chances of having a heart attack.
The procedure to insert a stent is much less invasive than coronary bypass surgery, which is usually recommended for people who have more than two narrowed arteries. Most people recover within a few days of having a stent inserted. In contrast, it may take you six weeks or more to recover from coronary bypass surgery. A stent can help you can get back to your regular schedule faster.
What are the risks of drug eluting stents?
Most people can safely tolerate drug-eluting stents. But like any medical procedure, coronary angioplasty and stenting do involve some risks, including:
allergic reaction to the anesthetic, dyes, or other materials used
kidney damage caused by the dye
bleeding or clotting
damage to your blood vessel
scarring of your blood vessel
abnormal heart rhythm, known as arrhythmia
heart attack or stroke, which are rare
In the event that scar tissue forms after stenting, your doctor may need to repeat the procedure. Report any chest pain to your doctor immediately. It could be a sign of a serious complication.
Questions to ask after stenting include:
When do I restart my medications? Do I need any new medications?
When should I see the doctor next?
Who do I call if I have problems after I go home?
Preventing blood clots — One of the most serious complications that can develop after stent placement is the development of a blood clot (thrombosis) inside the stent; this is called stent thrombosis. It is thought that the metal of the stent in contact with components of blood leads to clotting.
Stent thrombosis is rare because aspirin and a second drug that prevents clotting (anticoagulant) are given before and after stent placement. These two drugs are usually given for 6 to 12 months and sometimes longer, although some people may be treated with other drugs over a different time period. These medications should not be stopped without the approval of your cardiologist.