Coronary artery disease develops when the major blood vessels that supply your heart become damaged or diseased. Cholesterol-containing deposits (plaques) in your coronary arteries and inflammation are usually to blame for coronary artery disease.

The coronary arteries supply blood, oxygen and nutrients to your heart. A buildup of plaque can narrow these arteries, decreasing blood flow to your heart. Eventually, the reduced blood flow may cause chest pain (angina), shortness of breath, or other coronary artery disease signs and symptoms. A complete blockage can cause a heart attack.

Because coronary artery disease often develops over decades, you might not notice a problem until you have a significant blockage or a heart attack. But you can take steps to prevent and treat coronary artery disease. A healthy lifestyle can make a big impact.

If your coronary arteries narrow, they can't supply enough oxygen-rich blood to your heart — especially when it's beating hard, such as during exercise. At first, the decreased blood flow may not cause any symptoms. As plaque continues to build up in your coronary arteries, however, you may develop the following coronary artery disease signs and symptoms:

• Chest pain (angina). You may feel pressure or tightness in your chest, as if someone were standing on your chest. This pain, called angina, usually occurs on the middle or left side of the chest. Angina is generally triggered by physical or emotional stress. The pain usually goes away within minutes after stopping the stressful activity. In some people, especially women, the pain may be brief or sharp and felt in the neck, arm or back.
• Shortness of breath. If your heart can't pump enough blood to meet your body's needs, you may develop shortness of breath or extreme fatigue with activity.

• Heart attack. A completely blocked coronary artery will cause a heart attack. The classic signs and symptoms of a heart attack include crushing pressure in your chest and pain in your shoulder or arm, sometimes with shortness of breath and sweating.

  Women are somewhat more likely than men are to have less typical signs and symptoms of a heart attack, such as neck or jaw pain. And they may have other symptoms such as shortness of breath, fatigue and nausea.

  Sometimes a heart attack occurs without any apparent signs or symptoms.

When to see a doctor

If you think you're having a heart attack, immediately call 911 or your local emergency number. If you don't have access to emergency medical services, have someone drive you to the nearest hospital. Drive yourself only as a last option.

If you have risk factors for coronary artery disease — such as high blood pressure, high cholesterol, tobacco use, diabetes, obesity a strong family history of heart disease — talk to your doctor. Your doctor may want to test you for coronary artery disease, especially if you have signs or symptoms of narrowed arteries.

Coronary artery disease is thought to begin with damage or injury to the inner layer of a coronary artery, sometimes as early as childhood. The damage may be caused by various factors, including:

• Smoking
• High blood pressure
• High cholesterol
• Diabetes or insulin resistance
• Not being active (sedentary lifestyle)

Once the inner wall of an artery is damaged, fatty deposits (plaque) made of cholesterol and other cellular waste products tend to collect at the site of injury. This process is called atherosclerosis. If the plaque surface breaks or ruptures, blood cells called platelets clump together at the site to try to repair the artery. This clump can block the artery, leading to a heart attack.

Risk factors for coronary artery disease include:

• Age. Getting older increases your risk of damaged and narrowed arteries.
• Sex. Men are generally at greater risk of coronary artery disease. However, the risk for women increases after menopause.
• Family history. A family history of heart disease is associated with a higher risk of coronary artery disease, especially if a close relative developed heart disease at an early age. Your risk is highest if your father or a brother was diagnosed with heart disease before age 55 or if your mother or a sister developed it before age 65.
• Smoking. People who smoke have a significantly increased risk of heart disease. Breathing in secondhand smoke also increases a person's risk of coronary artery disease.
• High blood pressure. Uncontrolled high blood pressure can result in hardening and thickening of your arteries, narrowing the channel through which blood can flow.
• High blood cholesterol levels. High levels of cholesterol in your blood can increase the risk of formation of plaque and atherosclerosis. High cholesterol can be caused by a high level of low-density lipoprotein (LDL) cholesterol, known as the "bad" cholesterol. A low level of high-density lipoprotein (HDL) cholesterol, known as the "good" cholesterol, can also contribute to the development of atherosclerosis.
• Diabetes. Diabetes is associated with an increased risk of coronary artery disease. Type 2 diabetes and coronary artery disease share similar risk factors, such as obesity and high blood pressure.
• Overweight or obesity. Excess weight typically worsens other risk factors.
• Physical inactivity. Lack of exercise also is associated with coronary artery disease and some of its risk factors, as well.
• High stress. Unrelieved stress in your life may damage your arteries as well as worsen other risk factors for coronary artery disease.
• Unhealthy diet. Eating too much food that has high amounts of saturated fat, trans fat, salt and sugar can increase your risk of coronary artery disease.

Risk factors often occur together and one may trigger another. For instance, obesity can lead to type 2 diabetes and high blood pressure. When grouped together, certain risk factors make you even more likely to develop coronary artery disease. For example, metabolic syndrome — a cluster of conditions that includes high blood pressure; high triglycerides; low HDL, or "good," cholesterol; high insulin levels and excess body fat around the waist — increases the risk of coronary artery disease.

Sometimes coronary artery disease develops without any classic risk factors. Researchers are studying other possible risk factors, including:

• Sleep apnea. This disorder causes you to repeatedly stop and start breathing while you're sleeping. Sudden drops in blood oxygen levels that occur during sleep apnea increase blood pressure and strain the cardiovascular system, possibly leading to coronary artery disease.
• High-sensitivity C-reactive protein (hs-CRP). This protein appears in higher-than-normal amounts when there's inflammation somewhere in your body. High hs-CRP levels may be a risk factor for heart disease. It's thought that as coronary arteries narrow, you'll have more hs-CRP in your blood.
• High triglycerides. This is a type of fat (lipid) in your blood. High levels may raise the risk of coronary artery disease, especially for women.
• Homocysteine. Homocysteine is an amino acid your body uses to make protein and to build and maintain tissue. But high levels of homocysteine may increase your risk of coronary artery disease.
• Preeclampsia. This condition that can develop in women during pregnancy causes high blood pressure and a higher amount of protein in urine. It can lead to a higher risk of heart disease later in life.
• Alcohol use. Heavy alcohol use can lead to heart muscle damage. It can also worsen other risk factors of coronary artery disease.
• Autoimmune diseases. People who have conditions such as rheumatoid arthritis and lupus (and other inflammatory conditions) have an increased risk of atherosclerosis.

Coronary artery disease can lead to:

• Chest pain (angina). When your coronary arteries narrow, your heart may not receive enough blood when demand is greatest — particularly during physical activity. This can cause chest pain (angina) or shortness of breath.
• Heart attack. If a cholesterol plaque ruptures and a blood clot forms, complete blockage of your heart artery may trigger a heart attack. The lack of blood flow to your heart may damage your heart muscle. The amount of damage depends in part on how quickly you receive treatment.
• Heart failure. If some areas of your heart are chronically deprived of oxygen and nutrients because of reduced blood flow, or if your heart has been damaged by a heart attack, your heart may become too weak to pump enough blood to meet your body's needs. This condition is known as heart failure.
• Abnormal heart rhythm (arrhythmia). Inadequate blood supply to the heart or damage to heart tissue can interfere with your heart's electrical impulses, causing abnormal heart rhythms.

The same lifestyle habits used to help treat coronary artery disease can also help prevent it. A healthy lifestyle can help keep your arteries strong and clear of plaque. To improve your heart health, follow these tips:

• Quit smoking.
• Control conditions such as high blood pressure, high cholesterol and diabetes.
• Stay physically active.
• Eat a low-fat, low-salt diet that's rich in fruits, vegetables and whole grains.
• Maintain a healthy weight.
• Reduce and manage stress.

The doctor will ask questions about your medical history, do a physical exam and order routine blood tests. He or she may suggest one or more diagnostic tests as well, including:

• Electrocardiogram (ECG). An electrocardiogram records electrical signals as they travel through your heart. An ECG can often reveal evidence of a previous heart attack or one that's in progress.

• Echocardiogram. An echocardiogram uses sound waves to produce images of your heart. During an echocardiogram, your doctor can determine whether all parts of the heart wall are contributing normally to your heart's pumping activity.

  Parts that move weakly may have been damaged during a heart attack or be receiving too little oxygen. This may be a sign of coronary artery disease or other conditions.

• Exercise stress test. If your signs and symptoms occur most often during exercise, your doctor may ask you to walk on a treadmill or ride a stationary bike during an ECG. Sometimes, an echocardiogram is also done while you do these exercises. This is called a stress echo. In some cases, medication to stimulate your heart may be used instead of exercise.
• Nuclear stress test. This test is similar to an exercise stress test but adds images to the ECG recordings. It measures blood flow to your heart muscle at rest and during stress. A tracer is injected into your bloodstream, and special cameras can detect areas in your heart that receive less blood flow.

• Cardiac catheterization and angiogram. During cardiac catheterization, a doctor gently inserts a catheter into an artery or vein in your groin, neck or arm and up to your heart. X-rays are used to guide the catheter to the correct position. Sometimes, dye is injected through the catheter. The dye helps blood vessels show up better on the images and outlines any blockages.

  If you have a blockage that requires treatment, a balloon can be pushed through the catheter and inflated to improve the blood flow in your coronary arteries. A mesh tube (stent) is typically used to keep the dilated artery open.

• Cardiac CT scan. A CT scan of the heart can help your doctor see calcium deposits in your arteries that can narrow the arteries. If a substantial amount of calcium is discovered, coronary artery disease may be likely.

  A CT coronary angiogram, in which you receive a contrast dye that is given by IV during a CT scan, can produce detailed images of your heart arteries.

Treatment for coronary artery disease usually involves lifestyle changes and, if necessary, drugs and certain medical procedures.

Lifestyle changes

Making a commitment to the following healthy lifestyle changes can go a long way toward promoting healthier arteries:

• Quit smoking.
• Eat healthy foods.
• Exercise regularly.
• Lose excess weight.
• Reduce stress.

Drugs

Various drugs can be used to treat coronary artery disease, including:

• Cholesterol-modifying medications. These medications reduce (or modify) the primary material that deposits on the coronary arteries. As a result, cholesterol levels — especially low-density lipoprotein (LDL, or the "bad") cholesterol — decrease. Your doctor can choose from a range of medications, including statins, niacin, fibrates and bile acid sequestrants.

• Aspirin. Your doctor may recommend taking a daily aspirin or other blood thinner. This can reduce the tendency of your blood to clot, which may help prevent obstruction of your coronary arteries.

  If you've had a heart attack, aspirin can help prevent future attacks. But aspirin can be dangerous if you have a bleeding disorder or you're already taking another blood thinner, so ask your doctor before taking it.

• Beta blockers. These drugs slow your heart rate and decrease your blood pressure, which decreases your heart's demand for oxygen. If you've had a heart attack, beta blockers reduce the risk of future attacks.
• Calcium channel blockers. These drugs may be used with beta blockers if beta blockers alone aren't effective or instead of beta blockers if you're not able to take them. These drugs can help improve symptoms of chest pain.
• Ranolazine. This medication may help people with chest pain (angina). It may be prescribed with a beta blocker or instead of a beta blocker if you can't take it.
• Nitroglycerin. Nitroglycerin tablets, sprays and patches can control chest pain by temporarily dilating your coronary arteries and reducing your heart's demand for blood.
• Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs). These similar drugs decrease blood pressure and may help prevent progression of coronary artery disease.

Procedures to restore and improve blood flow

Sometimes more aggressive treatment is needed. Here are some options:

Angioplasty and stent placement (percutaneous coronary revascularization)

Your doctor inserts a long, thin tube (catheter) into the narrowed part of your artery. A wire with a deflated balloon is passed through the catheter to the narrowed area. The balloon is then inflated, compressing the deposits against your artery walls.

A stent is often left in the artery to help keep the artery open. Most stents slowly release medication to help keep the arteries open.

Coronary artery bypass surgery

A surgeon creates a graft to bypass blocked coronary arteries using a vessel from another part of your body. This allows blood to flow around the blocked or narrowed coronary artery. Because this requires open-heart surgery, it's most often reserved for people who have multiple narrowed coronary arteries.

Lifestyle changes can help you prevent or slow the progression of coronary artery disease.

• Stop smoking. Smoking is a major risk factor for coronary artery disease. Nicotine constricts blood vessels and forces your heart to work harder, and carbon monoxide reduces oxygen in your blood and damages the lining of your blood vessels. If you smoke, quitting is one of the best ways to reduce your risk of a heart attack.
• Control your blood pressure. Ask your doctor for a blood pressure measurement at least every two years. He or she may recommend more-frequent measurements if your blood pressure is higher than normal or you have a history of heart disease. Optimal blood pressure is less than 120 systolic and 80 diastolic, as measured in millimeters of mercury (mm Hg).

• Check your cholesterol. Adults should get a baseline cholesterol test when in their 20s and at least every five years after. Ask your doctor what your cholesterol levels should be. Most people should aim for an LDL cholesterol level below 130 milligrams per deciliter (mg/dL), or 3.4 millimoles per liter (mmol/L).

  If you have other risk factors for heart disease, your target LDL cholesterol may be below 100 mg/dL (2.6 mmol/L). Ask your doctor what level LDL is best for you. If your test results aren't meeting your targeted levels, you may need more-frequent cholesterol tests.

• Keep diabetes under control. If you have diabetes, tight blood sugar management can help reduce the risk of heart disease.
• Eat heart-healthy foods. Eat plenty of fruits, vegetables, whole grains, legumes and nuts. Avoid saturated fats and trans fats and reduce salt and sugar. Eating one or two servings of fish a week also may help keep your heart healthy.
• Avoid or limit alcohol. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women and up to two drinks a day for men.
• Get moving. Exercise helps manage weight and control diabetes, high cholesterol and high blood pressure — all risk factors for coronary artery disease. Get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week, or a combination of moderate and vigorous activity.
• Maintain a healthy weight. Being overweight increases your risk of coronary artery disease. Losing even just a small amount of weight can help reduce risk factors for coronary artery disease.
• Participate in cardiac rehabilitation. If you've had surgery, your doctor may suggest you participate in cardiac rehabilitation — a program of education, counseling and exercise training that's designed to help improve your health.
• Manage stress. Reduce stress as much as possible. Practice healthy techniques for managing stress, such as muscle relaxation and deep breathing.
• Get your flu shot. Get your flu (influenza) vaccine each year to reduce your risk of having influenza.

Regular medical checkups are also important. Some of the main risk factors for coronary artery disease — high cholesterol, high blood pressure and diabetes — have no symptoms in the early stages. Early detection and treatment can help you maintain better heart health.

Omega-3 fatty acids are a type of unsaturated fatty acid that's thought to reduce inflammation throughout the body, a contributing factor to coronary artery disease. However, some studies haven't found a benefit. More research is needed.

• Fish and fish oil. Fish and fish oil are the most effective sources of omega-3 fatty acids. Fatty fish — such as salmon, herring and light canned tuna — contain the most omega-3 fatty acids and, therefore, the most benefit. Fish oil supplements may offer benefit, but the evidence is strongest for eating fish.
• Flax and flaxseed oil. Flax and flaxseed oil also contain beneficial omega-3 fatty acids, though studies have not found these sources to be as effective as fish. The shells on raw flaxseeds also contain soluble fiber, which can help with constipation. More research is needed to determine if flaxseed can help lower blood cholesterol.
• Other dietary sources of omega-3 fatty acids. Other dietary sources of omega-3 fatty acids include canola oil, soybeans and soybean oil. These foods contain smaller amounts of omega-3 fatty acids than do fish and fish oil, and evidence for their benefit to heart health isn't as strong.

Other supplements may help reduce your blood pressure or cholesterol level, two contributing factors to coronary artery disease. These include:

• Alpha-linolenic acid
• Barley
• Cocoa
• Coenzyme Q10
• Fiber, including blond psyllium and oat bran (found in oatmeal and whole oats)
• Garlic
• Plant stanols and sterols (found in supplements and some margarines, such as Promise, Smart Balance and Benecol)

Always talk to your doctor before adding a new over-the-counter medication or supplement to your treatment plan. Some drugs and supplements can interfere with other medications and cause side effects or make them less effective.

If you know you have symptoms of or risk factors for coronary artery disease, you're likely to see your primary care doctor. Eventually, you may be referred to a heart specialist (cardiologist).

Here's some information to help you get ready for your appointment and to know what to expect from your doctor.

What you can do

• Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet. For some tests, for example, you may need to fast for a time beforehand.
• Write down any symptoms you're experiencing, including any that may seem unrelated to coronary artery disease.
• Write down your key medical information, including other conditions with which you've been diagnosed, all medications and supplements you're taking, and family history of heart disease.
• Find a family member or friend who can come with you to the appointment, if possible. Someone who accompanies you can help remember what the doctor says.
• Write down questions to ask your doctor.

Questions to ask your doctor at your initial appointment include:

• What are the possible causes for my signs and symptoms?
• What tests do I need?
• Should I see a specialist?
• Should I follow any restrictions while I wait for my next appointment?
• What emergency signs and symptoms should prompt a call to 911 or emergency medical help?

Questions to ask if you are referred to a cardiologist include:

• What is my diagnosis?
• What is my risk of long-term complications from this condition?
• What treatment do you recommend?
• If you're recommending medications, what are the possible side effects?
• Am I a candidate for surgery? Why or why not?
• What diet and lifestyle changes should I make?
• What restrictions do I need to follow, if any?
• How frequently will you see me for follow-up visits?
• I have these other health problems. How can I best manage these conditions together?

Don't hesitate to ask additional questions about your condition.

What to expect from your doctor

A doctor or cardiologist who sees you for heart-related signs and symptoms may ask:

• What are your symptoms?
• When did you begin experiencing symptoms?
• Have your symptoms gotten worse over time?
• Do you have chest pain or difficulty breathing?
• Does exercise or physical exertion make your symptoms worse?
• Are you aware of heart problems in your family?
• Have you been diagnosed with other health conditions?
• What medications are you taking?
• Have you ever been treated with radiation therapy?
• How much do you exercise in a typical week?
• What's your typical daily diet?
• Do you or did you smoke? How much? If you quit, when?
• Do you drink alcohol? How much?

What you can do in the meantime

It's never too early to make healthy lifestyle changes, such as quitting smoking, eating healthy foods and getting more exercise. These habits protect against coronary artery disease and its complications, including heart attack and stroke.