Coronary artery disease (CAD) is the most common form of heart disease and top cause of death in the United States. 1 This condition occurs when the coronary arteries, the blood vessels that supply oxygen-rich blood to your heart muscle, gradually become narrowed or blocked by plaque deposits. The plaque deposits decrease the space through which blood can flow. Poor blood flow can "starve" the heart muscle and lead to chest pain. A heart attack results when blood flow is completely blocked, usually by a blood clot forming over a plaque that has broken open (ruptured).
What causes coronary artery disease?
Coronary artery disease is caused by the buildup of plaque on the inside of your coronary arteries. Plaque is made up of excess cholesterol, calcium, and other substances in your blood that, over time, build up on the inside walls of your coronary arteries and other arteries. This process is called hardening of the arteries, or atherosclerosis. (See an illustration of atherosclerosis.) In many people, plaque may begin to form in childhood and gradually develops over a lifetime. 2 Smoking, high blood pressure
, and high cholesterol
all contribute to coronary artery disease.
What are the symptoms?
Since coronary artery disease develops slowly over decades, most people do not know that they have it until the disease is advanced. Typically, the earliest symptoms—chest pain, also called angina, and shortness of breath—occur after age 50.
Unfortunately, sometimes a heart attack is the first sign of coronary artery disease. According to the large, 50-year Framingham Heart Study, over 50% of men and 63% of women who died suddenly of coronary artery disease (mostly from heart attack) had no previous symptoms of this disease. 1
How is coronary artery disease diagnosed?
Your doctor will ask you about your risk factors and your symptoms and perform a complete physical exam. If coronary artery disease is suspected, you may have additional tests to confirm the diagnosis. The most common initial tests are electrocardiogram (EKG or ECG), which measures the electrical signals that control the rhythm of your heartbeat, chest X-ray, routine blood tests, and exercise electrocardiogram, commonly called a "stress test."
A stress EKG, and other tests, can show how severe your coronary artery disease is by testing how much you can exercise before symptoms develop. With cardiac catheterization
or coronary angiogram, a test that shows blood flow to your heart muscle, your doctor can see any blockages or narrowing and the location of those problems. This test is usually done when procedures to remove blockages, such as angioplasty or bypass surgery, are being considered.
How is it treated?
Your doctor will strongly advise that you make lifestyle changes. From 1989 to 1999, the death rate from coronary artery disease declined 24%. This decline is mainly attributed to the steps people are taking to prevent the disease, including lowering blood pressure and cholesterol, changing diet and exercise habits, quitting smoking, and improved medical care. 3 You too can take measures to stop and possibly even reverse coronary artery disease.
Quitting smoking may be the most important step you can take to reduce your risk of heart disease. According to the World Health Organization, the risk of coronary artery disease decreases by 50% in the first year after quitting. 1
Aggressive lowering of your cholesterol level and blood pressure is recommended for people with coronary artery disease. Your doctor may first suggest a low-fat diet and exercise to reduce cholesterol and blood pressure. If lifestyle changes alone do not reduce your risk factors, medications may be tried. A cholesterol-lowering medication is often considered if you do not reach your target cholesterol level after at least 3 months of diet and exercise. 4 A 10% decrease in total cholesterol
levels (population-wide) may result in an estimated 30 percent reduction in the incidence of coronary artery disease. 1
Regular exercise can lower your blood pressure too. Less active, less fit persons have a 30% to 50% greater risk of developing high blood pressure. 3 Regular exercise and a low-fat diet should also help you lose weight, and your heart will not have to work as hard.
With these measures, you may be able to stop the disease and improve the quality and length of your life. However, many people must take medications for the rest of their lives, and a smaller portion require surgical treatment
to improve blood flow to heart muscle.
If you have frequent chest pain that makes normal everyday activities difficult, your doctor may recommend further treatment such as:
* Angioplasty, a procedure to open blocked coronary arteries, with or without stenting. During stent placement, a small, coiled wire-mesh tube is inserted into the coronary artery and expanded during angioplasty.
* Atherectomy, a procedure which removes fat and calcium buildup in the arteries that supply the heart.
These are the preferred treatments because these less invasive procedures
do not require major surgery. However, they are not appropriate in all cases, and coronary artery bypass surgery may be necessary.
Which new research advances should I know about?
Newly developed stents, called drug-eluting stents, could become one of the biggest breakthroughs in the treatment of cardiovascular disease
, according to the American Heart Association. Stents are small, wire-mesh tubes that when inserted into a blocked section of the coronary artery open up the artery and improve blood flow. (See an illustration of a stent.) While conventional stents have proved to be a valuable tool in opening coronary arteries, occasionally the arteries closed again. Drug-eluting stents are coated with medications that prevent the growth of cells around the stent and thus are more effective than conventional stents in keeping the artery open.