Coronary Artery Disease
What Is It?
Coronary artery disease is the term commonly used to describe the buildup of fatty deposits and fibrous tissue (plaques) inside the arteries that supply blood to the heart (the coronary arteries). This buildup is called atherosclerosis. Coronary atherosclerosis eventually can cause the coronary arteries to become significantly narrower, which decreases the blood supply to portions of the heart muscle and triggers a specific type of Chest pain called angina. Atherosclerosis also can cause a blood clot to form inside a narrowed coronary artery. When this happens, the result is a Heart Attack, which can cause significant damage to the heart muscle.
The factors that increase the risk of developing coronary artery disease are basically the same as those for atherosclerosis:
- A high blood cholesterol level
- A high level of LDL cholesterol, commonly called “bad cholesterol”
- A low level of HDL cholesterol, commonly called “good cholesterol”
- High blood pressure (hypertension)
- Family history of coronary artery disease at a younger age
- Cigarette smoking
- Physical inactivity (too little regular exercise)
Coronary artery disease is the most common chronic, life-threatening illness in the United States. It affects 11 million Americans. Earlier in life, men have a greater risk of coronary artery disease than women. However, a woman’s risk eventually equals or excels that of a man after she begins menopause.
Although coronary artery disease from atherosclerosis is the most common reason for arteries to become blocked, there are rarer cases in which problems in the coronary arteries result from other medical conditions. These conditions include:
- A blood clot in a coronary artery resulting from an abnormal tendency of the blood to form clots (hypercoagulability)
- Inflammation of a coronary artery resulting from rheumatoid arthritis or a collagen vascular disease (such as lupus)
- Cocaine abuse
- Spasm of a coronary artery
- A small traveling blood clot (embolus) that floats into a coronary artery and lodges there
- An inherited (congenital) abnormality of a coronary artery
In most patients, the most common symptom of coronary artery disease is the type of Chest pain called angina, or angina pectoris. Angina usually is described as a squeezing, pressing or burning chest pain that tends to be focused either in the center of the chest or just below the center of the rib cage. It also can spread to the arms (especially the left arm), abdomen, neck, lower jaw or neck. Other symptoms can include sweating, nausea, dizziness or light-headedness, breathlessness or palpitations (often associated with the symptoms of a heart attack). Sometimes, when coronary artery disease produces burning chest pain and nausea, a patient may mistake heart symptoms for indigestion.
There are two types of chest pain related to coronary artery disease — stable angina and acute coronary syndrome.
In stable angina, chest pain follows a predictable pattern, usually occurring after extreme emotion, overexertion, a large meal, cigarette smoking or exposure to extreme hot or cold temperatures. Symptoms usually last one to five minutes, and they disappear after a few minutes of rest. Stable angina is caused by a smooth plaque that partially obstructs blood flow in one or more coronary arteries.
Acute coronary syndrome (ACS) is much more dangerous. In most cases of ACS, fatty plaque inside an artery has developed a tear or break. The uneven surface can cause blood to clot on top of the disrupted plaque. This sudden blockage of blood flow results in unstable angina or a heart attack (myocardial infarction). In Unstable angina, chest pain symptoms are more pronounced and less predictable compared to stable angina. Chest pains occur more frequently, often at rest, and last several minutes to hours. In addition, people with unstable angina frequently develop profuse sweating with aching in the jaw, shoulders and arms.
Many people with coronary artery disease, especially women, do not have any symptoms or have unusual symptoms. In these people, the only sign of coronary artery disease may be a suspicious change in the pattern of a test called an electrocardiogram (EKG), which records the heart’s electrical activity. The test can be done at rest or during exercise (Exercise stress test). The stress test is able to detect the problem in the coronary artery because exercise increases the heart muscle’s demand for blood, a demand that can’t be met when the coronary arteries are significantly narrowed. In areas of the heart affected by narrowed coronary arteries, the heart muscle starves for blood and oxygen, and its electrical activity changes. This altered electrical activity is reflected in the patient’s EKG results.
If the problem is not discovered, the first symptom of coronary artery narrowing may be the severe chest pain of a Heart Attack. If a heart attack occurs, the patient has a 15 percent chance of dying before receiving medical attention.
Coronary artery disease usually is diagnosed after a person has chest pain or other symptoms such as shortness of breath with physical activity.
Your doctor may suspect that you have coronary artery disease based on your medical history and the pattern of your symptoms. To confirm the diagnosis, he or she first will examine you, paying special attention to your chest and heart. During the physical examination, your doctor will press on your chest to see if it is tender. Tenderness in the area where you have chest pain could be a sign of a non-cardiac problem involving chest muscles, ribs or rib joints. Your doctor also will use a stethoscope to listen for any abnormal heart sounds. The physical examination will be followed by one or more diagnostic tests to look for coronary artery disease. Possible tests include:
- An EKG — An EKG is a record of the heart’s electrical impulses. It can identify abnormalities in heart rate and rhythm, and it can provide clues that part of your heart muscle isn’t getting enough blood.
- Blood test for heart enzymes — When heart muscle is damaged, even a little, enzymes leak out of the damaged muscle cells into the bloodstream. Elevated heart enzymes suggest a heart problem.
- An Exercise stress test on a treadmill — An Exercise stress test monitors the effects of treadmill exercise on blood pressure and EKG and can identify heart problems.
- An Echocardiogram — This test uses ultrasound to produce images of the heart’s movement with each beat.
- Imaging test with radioactive tracers — In this test, a radioactive material is injected and is taken up by the heart muscle, which helps certain features show up on images taken with special cameras.
- A coronary angiogram (a series of X-rays of the coronary arteries) — The coronary angiogram is considered the most accurate way to measure the severity of coronary disease. During an angiogram, a thin, long, flexible tube called a catheter is inserted into an artery in the forearm or groin, and then threaded through the circulatory system into the coronary arteries. Dye is injected to show the blood flow within the coronary arteries and to identify any areas of narrowing or blockage.
Coronary artery disease is a long-term condition, and patients can have different patterns of symptoms. Plaque in coronary arteries never will disappear completely. However, with diet, exercise and proper medication, the heart muscle adapts to decreased blood flow, and new, small blood channels can develop to increase the blood flow to the heart muscle.
You can help to prevent coronary artery disease by controlling your risk factors for atherosclerosis. To do this:
- Quit smoking.
- Eat a healthy diet.
- Reduce your high blood LDL cholesterol (“bad cholesterol”).
- Reduce high blood pressure.
- Lose weight and exercise to prevent diabetes.
Coronary artery disease caused by atherosclerosis is treated with:
- Lifestyle changes — These include weight loss in obese patients, quitting smoking, diet and medications to lower High cholesterol, regular exercise, and stress reduction techniques (meditation, biofeedback, etc.).
- Nitrates (including nitroglycerin) — These medications widen blood vessels (vasodilators). Nitrates widen the coronary arteries and increase the blood flow to the heart muscle. They also widen the body’s veins, which lightens the heart’s workload by decreasing the amount of blood returning to the heart for pumping.
- Beta-blockers, such as atenolol (Tenormin) and metoprolol (Lopressor) — These medications decrease the heart’s workload by slowing the heart rate and reducing the force of heart muscle contractions, especially during exercise. People who have had a heart attack should try to stay on a beta-blocker for life to reduce the risk of a second heart attack.
- Aspirin — Because aspirin helps to prevent blood clots from forming inside narrowed coronary arteries, it can reduce the risk of heart attack in people who already have coronary artery disease. Doctors often advise patients older than 50 to take a low dose of aspirin daily to help prevent a heart attack.
- Cholesterol-lowering medications — Statins — such as lovastatin (Mevacor), simvastatin (Zocor), pravastatin (Pravachol) and atorvastatin (Lipitor) — have had the greatest impact on improving the risk of heart attack and death in people with coronary artery disease and those at risk of coronary artery disease. Statins lower LDL cholesterol and may raise HDL cholesterol slightly. Taking a statin regularly also helps to prevent plaques from tearing or breaking, which decreases the chance of a heart attack or worsening of angina. Niacin lowers LDL cholesterol, raises HDL cholesterol, and also lowers triglyceride levels. Medications called fibrates, such as gemfibrozil (Lopid), are used primarily in people with high triglyceride levels. A new medication — ezetimibe (Zetia) — that has recently been introduced decreases absorption of cholesterol from food.
- Calcium channel blockers, such as long-acting nifedipine (Adalat, Procardia), verapamil (Calan, Isoptin), diltiazem (Cardizem), amlodipine (Norvasc) — These medications may help to decrease the frequency of chest pain in patients with angina.
If your stable angina limits you physically because of chest pain, your doctor likely will advise you to have a coronary artery angiography (cardiac catheterization) to look for significant blockages. A heart specialist (cardiologist) also may do this test to diagnose coronary artery disease when other tests are not conclusive, in an emergency when a person is having a heart attack, and in some patients with newly diagnosed congestive heart failure.
When one or more significant blockages are found, the heart specialist will determine if the blockage(s) can be opened with a procedure called Balloon angioplasty, also called percutaneous transluminal coronary angioplasty or PTCA. In balloon angioplasty, a catheter is inserted into an artery in the groin or forearm, and then threaded through the circulatory system into the blocked coronary artery. Once inside the coronary artery, a small balloon at the catheter tip is inflated briefly to open the narrowed blood vessel. Usually, balloon inflation is followed by the placement of a stent, a wire mesh that expands with the balloon. The wire mesh remains inside the artery to keep it open. The balloon is deflated and the catheter is removed.
If the blockages cannot be opened with balloon angioplasty, the cardiologist will suggest coronary artery bypass surgery (CABG). CABG involves grafting one or more blood vessels onto the affected coronary arteries to bypass the narrowed or blocked areas. The blood vessels to be grafted can be taken from an artery inside the chest, an artery in the arm, and from a long vein in the leg.
The goal of treating heart attacks or sudden worsening of angina is to restore blood flow rapidly to the section of heart muscle no longer getting blood flow. Patients immediately receive medication to relieve pain. They also receive a beta-blocker to slow the heart rate and decrease the work of the heart and aspirin combined with other medications to dissolve or inhibit blood clotting. When possible, patients are transferred to a cardiac catheterization laboratory for immediate angiography and balloon angioplasty of the most significant blockage. In some people with coronary artery disease, other symptoms or complications will require treatment with additional therapies. For example, medication may be needed to treat cardiac arrhythmias (abnormal heart rhythms), low blood pressure or heart failure.
When To Call A Professional
Seek emergency help immediately if you have chest pain, even if you think that you are too young to be having heart problems. In patients whose chest pain signals heart attack, prompt treatment can limit heart muscle damage.
Because the extent of coronary artery disease does not always match the severity and length of chest pain, it is important for patients with chest pain to have their symptoms evaluated promptly by a doctor. You should not waste precious time by just watching the clock and hoping that your chest pain disappears. Remember, in about 15 percent of patients having a heart attack, death occurs soon after chest symptoms begin, and the patients never reach the hospital alive.
In people with coronary artery disease, the outlook depends on many factors. People with stable angina who are taking medications regularly, eating properly, and exercising as instructed by their doctors generally remain active. The prognosis for heart attacks when people reach the emergency room promptly has improved dramatically over the past 10 years. However, many people still die before reaching the hospital. This is why it is so important to prevent coronary artery disease.
Last Edited: 15 Aug. 2005
by David A. Scott, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.