Coronary artery disease (CAD) is a common type of heart disease. It affects the main blood vessels that supply blood to the heart, called the coronary arteries. In CAD, there is reduced blood flow to the heart muscle. A buildup of fats, cholesterol and other substances in and on the artery walls, a condition called atherosclerosis, usually causes coronary artery disease. The buildup, called plaque, makes the arteries narrow.

Coronary artery disease often develops over many years. Symptoms are from the lack of blood flow to the heart. They may include chest pain and shortness of breath. A complete blockage of blood flow can cause a heart attack.

Treatment for coronary artery disease may include medicines and surgery. Eating a nutritious diet, getting regular exercise and not smoking can help prevent coronary artery disease and the conditions that can cause it.

Coronary artery disease also may be called coronary heart disease.

Symptoms of coronary artery disease happen when the heart doesn't get enough oxygen-rich blood. Coronary artery disease symptoms may include:

• Chest pain, called angina. You may feel squeezing, pressure, heaviness, tightness or pain in the chest. It may feel like somebody is standing on your chest. The chest pain usually affects the middle or left side of the chest. Activity or strong emotions can trigger angina. There are different types of angina. The type depends on the cause and whether rest or medicine makes symptoms better. In some people, especially women, the pain may be brief or sharp and felt in the neck, arm or back.
• Shortness of breath. You may feel like you can't catch your breath.
• Fatigue. If the heart can't pump enough blood to meet your body's needs, you may feel unusually tired.

Symptoms of coronary artery disease may not be noticed at first. Sometimes symptoms only happen when the heart is beating hard, such as during exercise. As the coronary arteries continue to narrow, symptoms can get more severe or frequent.

A completely blocked coronary artery will cause a heart attack. Common heart attack symptoms include:

• Chest pain that may feel like pressure, tightness, squeezing or aching.
• Pain or discomfort that spreads to the shoulder, arm, back, neck, jaw, teeth or sometimes the upper belly.
• Cold sweats.
• Fatigue.
• Heartburn.
• Nausea.
• Shortness of breath.
• Lightheadedness or sudden dizziness.

Chest pain is usually the most common symptom of heart attack. But for some people, such as women, the elderly and those with diabetes, symptoms may seem unrelated to a heart attack. For example, they may have nausea or a very brief pain in the neck or back. Some people having a heart attack don't notice 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.

Smoking or having high blood pressure, high cholesterol, diabetes, obesity or a strong family history of heart disease makes you more likely to get coronary artery disease. If you're at high risk of coronary artery disease, talk to your healthcare professional. You may need tests to check for narrowed arteries and coronary artery disease.

Coronary artery disease is caused by the buildup of fats, cholesterol and other substances in and on the walls of the heart arteries. This condition is called atherosclerosis. The buildup is called plaque. Plaque can cause the arteries to narrow, blocking blood flow. The plaque also can burst, causing a blood clot.

Some causes of atherosclerosis and coronary artery disease are:

• Diabetes or insulin resistance.
• High blood pressure.
• Lack of exercise.
• Smoking or tobacco use.

Coronary artery disease is common.

Coronary artery disease risk factors you can't control include:

• Age. Getting older increases the risk of damaged and narrowed arteries.
• Birth 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 makes you more likely to get coronary artery disease. This is especially true if a parent, brother, sister or child got heart disease at an early age. The risk is highest if your father or a brother had heart disease before age 55 or if your mother or a sister developed it before age 65.

Coronary artery disease risk factors you can control are:

• Smoking. If you smoke, quit. Smoking is bad for heart health. People who smoke have a much greater risk of heart disease. Breathing in secondhand smoke also increases the risk.
• High blood pressure. Uncontrolled high blood pressure can make arteries hard and stiff. This can lead to atherosclerosis, which causes coronary artery disease.
• Cholesterol. Too much "bad" cholesterol in the blood can increase the risk of atherosclerosis. "Bad" cholesterol is called low-density lipoprotein (LDL) cholesterol. Not enough "good" cholesterol, called high-density lipoprotein (HDL) cholesterol, also leads to atherosclerosis.
• Diabetes. Diabetes increases the risk of coronary artery disease. Type 2 diabetes and coronary artery disease share some risk factors, such as obesity and high blood pressure.
• Obesity. Too much body fat is bad for overall health. Obesity can lead to type 2 diabetes and high blood pressure. Ask your healthcare team what a healthy weight is for you.
• Chronic kidney disease. Having long-term kidney disease increases the risk of coronary artery disease.
• Not getting enough exercise. Physical activity is important for good health. A lack of exercise is linked to coronary artery disease and some of its risk factors.
• A lot of stress. Emotional stress may damage the arteries and worsen other risk factors for coronary artery disease.
• Unhealthy diet. Eating foods with a lot of saturated fat, trans fat, salt and sugar can increase the risk of coronary artery disease.
• Alcohol use. Heavy alcohol use can lead to heart muscle damage. It also can worsen other risk factors of coronary artery disease.
• Amount of sleep. Too little sleep and too much sleep both have been linked to an increased risk of heart disease.

Risk factors often happen together. One risk factor may trigger another. When grouped together, some risk factors make you even more likely to develop coronary artery disease. For example, metabolic syndrome is a group of conditions that includes high blood pressure, high blood sugar, too much body fat around the waist and high triglyceride levels. Metabolic syndrome increases the risk of coronary artery disease.

Other possible risk factors for coronary artery disease may include:

• Breathing pauses during sleep, called obstructive sleep apnea. This condition causes breathing to stop and start during sleep. It can cause sudden drops in blood oxygen levels. The heart must work harder to pump blood. Blood pressure goes up.
• Increased high-sensitivity C-reactive protein (hs-CRP). This protein appears in higher than usual amounts when there's inflammation somewhere in the body. High hs-CRP levels may be a risk factor for heart disease. It's thought that as coronary arteries narrow, the level of hs-CRP in the blood goes up.
• High triglycerides. This is a type of fat in the blood. High levels may raise the risk of coronary artery disease, especially for women.
• High levels of homocysteine. Homocysteine is a substance that the body uses to make protein and to build and maintain tissue. But high levels of homocysteine may raise the risk of coronary artery disease.
• Preeclampsia. This pregnancy complication causes high blood pressure and increased protein in the urine. It can lead to a higher risk of heart disease later in life.
• Other pregnancy complications. Diabetes or high blood pressure during pregnancy are known risk factors for coronary artery disease.
• Certain autoimmune diseases. People who have conditions such as rheumatoid arthritis and lupus have an increased risk of atherosclerosis.

Complications of coronary artery disease may include:

• Chest pain, also called angina. This is a symptom of coronary artery disease. But it also can be a complication of worsening CAD. The chest pain happens when arteries narrow and the heart doesn't get enough blood.
• Heart attack. A heart attack can happen if atherosclerosis causes a blood clot. A clot can block blood flow. The lack of blood can damage the heart muscle. The amount of damage depends in part on how quickly you are treated.
• Heart failure.Narrowed arteries in the heart or high blood pressure can slowly make the heart weak or stiff. This can make it harder for the heart to pump blood.
• Irregular heart rhythms, called arrhythmias. If the heart doesn't get enough blood, changes in heart signaling can happen. This can cause irregular heartbeats.

To diagnose coronary artery disease, a healthcare professional examines you. You are usually asked questions about your medical history and any symptoms. If you have symptoms of coronary artery disease such as chest pain or shortness of breath, tests may be done to check your overall health.

Tests

Tests to help diagnose or watch coronary artery disease include:

• Blood tests. Blood tests can check blood sugar and cholesterol levels. A high-sensitivity C-reactive protein (CRP) test checks for a protein linked to inflammation of the arteries.
• Electrocardiogram (ECG or EKG). This quick test checks the electrical activity of the heart. It shows how the heart is beating. Sticky patches called electrodes attach to the chest and sometimes the arms and legs. Wires connect the electrodes to a computer, which prints or displays the test results. The ECG signal patterns can show if you had or are having a heart attack.
• Echocardiogram. This test uses sound waves to show blood flow through the heart. Parts of the heart that move weakly may be caused by a lack of oxygen or a heart attack. This may be a sign of coronary artery disease or other conditions.
• Exercise stress test. If your symptoms usually occur during exercise, your healthcare professional may recommend this test. You walk on a treadmill or ride a stationary bike while your heart is checked. Because exercise makes the heart pump harder and faster than it does during most daily activities, an exercise stress test can show heart problems that might otherwise be missed. If you can't exercise, you may be given a medicine that affects the heart like exercise does. Sometimes an echocardiogram is done during an exercise stress test.
• Nuclear stress test. This test shows how blood moves to the heart at rest and during activity. It uses a small amount of radioactive material, called a tracer or radiotracer. The substance is given by IV. An imaging machine takes pictures of how the tracer moves through the heart arteries. This helps find areas of poor blood flow or heart damage.
• Heart CT scan. A CT scan of the heart can show calcium deposits and blockages in the heart arteries. Calcium deposits can narrow the arteries. Sometimes dye is given by IV during this test. The dye helps create detailed pictures of the heart arteries. If dye is used, the test is called a CT coronary angiogram.
• Cardiac catheterization and angiogram. This test can see blockages in the heart arteries. A doctor places a long, thin flexible tube called a catheter in a blood vessel, usually in the groin or wrist. It's guided to the heart. Dye flows through the catheter to arteries in the heart. The dye helps the arteries show up more clearly on X-ray images and video. Heart treatments may be done during this test.

Omega-3 fatty acids are a type of unsaturated fatty acid. It's thought that they can lower inflammation throughout the body. Inflammation has been linked to coronary artery disease. However, the reasons for and against omega-3 fatty acids for heart disease continue to be studied.

Sources of omega-3 fatty acids include:

• 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 — have the most omega-3 fatty acids. Fish oil supplements may offer benefit, but the evidence is strongest for eating fish.
• Flax and flaxseed oil. Flax and flaxseed oil contain a type of omega-3 fatty acid called alpha-linolenic acid (ALA). ALA contains smaller amounts of omega-3 fatty acids than do fish and fish oil. ALA may help lower cholesterol and improve heart health. But research is mixed. Some studies haven't found flax and flaxseed oil to be as effective as fish. Flaxseed also contains a lot of fiber, which has various health benefits.
• Other oils. Alpha-linolenic acid (ALA) also can be found in canola oil, soybeans and soybean oil.

Other supplements and food items may help lower blood pressure or cholesterol — two risk factors for coronary artery disease. Some that may work are:

• Barley.
• Psyllium, a type of fiber.
• Oats, a type of fiber that includes beta-glucans and is found in oatmeal and whole oats.
• Garlic.
• Plant sterols, found in supplements and some margarines, such as Promise, Smart Balance and Benecol.

Always talk to a healthcare professional before taking herbs, supplements or medicines bought without a prescription.

Making certain lifestyle changes can help keep the arteries healthy and can prevent or slow coronary artery disease. Try these heart-healthy tips:

• Don't smoke or use tobacco. Smoking is a major risk factor for coronary artery disease. Nicotine tightens blood vessels and forces the heart to work harder. Not smoking is one of the best ways to lower the risk of a heart attack. If you need help quitting, talk to your healthcare team.
• Eat heart-healthy foods. Choose plenty of fruits, vegetables and whole grains. Limit sugar, salt and saturated fats. Eating one or two servings of fish a week also may help keep the heart healthy.
• Get regular exercise. Exercise helps manage weight and control diabetes, cholesterol and blood pressure — all risk factors for coronary artery disease. Try to get 30 to 60 minutes of physical activity most days of the week. Ask your healthcare team what amount and type of exercise is best for you.
• Keep a healthy weight. Being overweight increases the risk of coronary artery disease. Losing even a small amount of weight can help reduce risk factors for coronary artery disease. Ask your healthcare team what the best weight is for you.
• Control blood pressure. Adults should get their blood pressure checked by a healthcare professional at least every two years. You may need to have checks more often if you have a history of high blood pressure. Ask your health professional what blood pressure goal is best for you.
• Get your cholesterol checked. Ask your healthcare team how often you need a cholesterol test. Lifestyle changes and medicines may be recommended to control cholesterol.
• Check your blood sugar. If you have diabetes, carefully managing your blood sugar can help reduce the risk of coronary artery disease.
• 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 good sleep. Poor sleep may increase the risk of heart disease and other chronic conditions. Adults should aim to get 7 to 9 hours of sleep daily.
• Manage stress. Find ways to help reduce emotional stress. Getting more exercise, practicing mindfulness and connecting with others in support groups are some ways to reduce stress.

Regular health checkups also are 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 keep your heart healthy. Also ask about recommended vaccines, such as a yearly flu vaccine.

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

• Do not smoke or use tobacco.
• Limit or do not drink alcohol.
• Control blood pressure, cholesterol and diabetes.
• Exercise and stay active.
• Maintain a healthy weight.
• Eat a low-fat, low-salt diet that's rich in fruits, vegetables and whole grains.
• Reduce and manage stress.
• Get 7 to 9 hours of sleep daily.

If you have symptoms of coronary artery disease or any risk factors, make an appointment for a health checkup. You may be sent to a doctor trained in heart diseases, called a cardiologist.

Here's some information to help you get ready for your appointment.

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 example, you may be told not to eat or drink for a few hours before a cholesterol test.
• Write down any symptoms you're having, including any that may seem unrelated to coronary artery disease.
• Write down your medical information, including other conditions you have and any family history of heart disease.
• Bring a list of medicines with you to your appointment. Include doses.
• Ask a family member or friend to go with you to the appointment, if possible. An extra person can help you remember details from the appointment..
• Write down questions to ask your healthcare team.

Questions to ask your healthcare professional at your first appointment include:

• What is causing my symptoms?
• What tests do I need?
• Should I see a specialist?
• Do I need to change my activity or diet while I wait for my next appointment?
• When should I call 911 or emergency medical help for my symptoms?

If you're sent to a cardiologist for coronary artery disease, you may want to ask these questions:

• What is my risk of long-term complications from coronary artery disease?
• What treatment do you recommend?
• If I need medicine, what are the possible side effects?
• Do I need surgery? Why or why not?
• What diet and lifestyle changes should I make?
• How often do I need follow-up visits?
• I have other health conditions. How can I best manage these conditions together?

Don't hesitate to ask additional questions.

What to expect from your doctor

A healthcare professional who sees you for coronary artery disease may ask:

• What are your symptoms?
• When did you begin having symptoms?
• Have the symptoms gotten worse over time?
• Do you have chest pain or difficulty breathing?
• If so, what does the chest pain feel like?
• Does exercise or activity make the symptoms worse?
• Does anyone in your family have a heart condition or high blood pressure?
• Have you been diagnosed with other health conditions?
• What medicines do you take?
• How much do you exercise in a typical week?
• What's your usual 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.