What is Coronary Artery Disease? Symptoms & Causes of CAD

Coronary artery disease (CAD) is the most common type of heart disease in the United States, affecting more than 18 million people. Coronary artery disease might also be called coronary heart disease or ischemic heart disease. This disease occurs when cholesterol deposits cause the blood vessels that bring blood to your heart, called your coronary arteries, to become more narrow.1

Coronary Artery Disease Signs and Symptoms

Coronary artery disease is a chronic (long-term) condition, and it can take years until you notice any symptoms. The symptoms you feel are caused when the coronary artery becomes so narrow that the muscles of your heart don’t get enough blood or oxygen (called ischemia).2

Coronary artery disease symptoms can be chronic or sudden. The chronic form of coronary artery disease is also known as stable ischemic heart disease. The sudden form of coronary artery disease is a heart attack.2

Stable Ischemic Heart Disease

People with stable ischemic heart disease may feel symptoms of coronary artery disease day-to-day. The symptoms can include:3

  • Chest pain — Also known as angina, coronary artery disease chest pain usually gets worse with physical activity or strong emotions but gets better with rest. Most people feel it on the left side or middle of their chests, but some people feel pain in their arms, neck, or back.
  • Shortness of breath — Some people with coronary artery disease feel like they have a hard time catching their breath. They may also feel out of breath during light physical activity.
  • Fatigue — People with coronary artery disease may feel tired even when they get enough rest; this is because their heart can’t pump enough blood to meet their body’s needs.

Heart Attack

The symptoms of coronary artery disease can be hard to recognize at first.  For some people, the first sign of coronary artery disease is a heart attack — also called a myocardial infarction.1,3

A heart attack can happen when a coronary artery becomes completely blocked. The symptoms of a heart attack include:1

  • Chest pain — that might feel like squeezing, pressure, tightness, or heartburn (indigestion)
  • Neck, arm, back, shoulder, or jaw pain
  • Light-headedness or dizziness
  • Nausea
  • Sweating

Some people have different symptoms of a heart attack or no symptoms at all. Women are more likely than men to experience less common symptoms of a heart attack such as:4

  • Dizziness
  • Fatigue
  • Stomach pain and nausea
  • Chest tightness

A heart attack is a medical emergency, and you should call 911 or seek medical attention right away if you experience these symptoms.1

Causes of Coronary Artery Disease

Coronary artery disease is caused by a condition called atherosclerosis.2,5 In atherosclerosis, a plaque made of fat, cholesterol, calcium, and other substances begins to build up on the walls of your coronary arteries over time. As the plaque grows, it can block the blood flow to the muscles of your heart, causing the symptoms of coronary artery disease.5

Some cases of coronary artery disease can be caused by problems with how blood vessels work. Normally, your blood vessels widen when they get signals that more blood and oxygen are needed, such as during exercise or stress. For some people, the blood vessels around the heart don’t widen in response to these signals and may stay the same size or even get narrower. When this happens, the heart can’t get enough oxygen.6

Researchers aren’t sure exactly why this happens, but it may involve damage to the blood vessels from inflammation, high blood pressure, or diabetes.6

Coronary Artery Disease Risk Factors

Your risk of coronary artery disease increases based on how many risk factors you have. Some risk factors you can’t control (non-modifiable risk factors), while others can be changed with lifestyle changes (modifiable risk factors).2

Non-Modifiable Risk Factors for Coronary Artery Disease

Non-modifiable risk factors are things that you can’t change, such as:6

  • Age — Your risk of coronary artery disease increases as you get older.
  • Sex — Coronary artery disease is more common in men, and on average, men tend to get CAD about 10 years earlier than women. The reason for this could be because of increased levels of estrogen in women that may protect against developing atherosclerosis. Women who begin menopause before the age of 40 may also have an increased risk.2
  • Family history of heart disease— Your risk of coronary artery disease may be increased if a close family member develops heart disease at a young age. This is especially true if you have a father or brother diagnosed with heart disease before age 55 or if your mother or sister was diagnosed before age 65.

Modifiable Risk Factors for Coronary Artery Disease

Modifiable risk factors are lifestyle habits that you can change, such as:6

  • Lack of physical activity
  • Smoking
  • Increased stress
  • A diet high in unhealthy fats and refined carbohydrates (such as white bread, pasta, and white rice)
  • Exposure to air pollution

Medical Conditions that Increase the Risk of Coronary Artery Disease

Some medical conditions can increase your risk of developing coronary artery disease. This is especially true of medical conditions that increase the risk of atherosclerosis, such as high cholesterol and high blood pressure. It’s also possible to be born with defects in your coronary arteries.6

Other medical conditions that aren’t directly related to your heart can also increase your risk of coronary artery disease, such as:2,6

  • Autoimmune disease (such as lupus, rheumatoid arthritis, Crohn’s disease, psoriasis, and ulcerative colitis)
  • Chronic kidney disease
  • Diabetes
  • Obesity
  • Metabolic syndrome — a cluster of conditions that increase your risk of coronary artery disease, including high blood pressure, high blood sugar, high cholesterol, and excess fat in the abdomen
  • Sleep problems — such as sleep apnea or lack of sleep

Some risk factors only affect women and people assigned female at birth, including:2

  • Menopause before the age of 40
  • Endometriosis — a condition causing painful, heavy periods and fertility issues
  • A history of pregnancy complications — including gestational diabetes, eclampsia, or preeclampsia
  • Taking hormonal birth control, depending on the type of hormonal birth control and how long you take it for

Cardiac Risk Calculator

Your healthcare provider can use the information about your personal risk factors to calculate how likely you are to develop heart disease, like coronary artery disease, in the next 10 years and over your lifetime.7

The American College of Cardiology (ACC) Atherosclerotic Cardiovascular Disease (ASCVD) Risk Calculator works for people between the ages of 40 and 79 to estimate the risk of heart disease over the next 10 years. It can also estimate the lifetime risk of heart disease for people between the ages of 20 and 59.8

Diagnosing Coronary Artery Disease

Health care providers can diagnose coronary artery disease by asking you questions about your symptoms and medical history and performing a physical exam and various other tests.9

To help diagnose coronary artery disease, your provider might ask you questions about your past and current symptoms, medical history, and family history. Your provider may also measure your blood pressure and listen to your heart using a stethoscope.9

Tests to help diagnose coronary artery disease include:2,10,11

  • Blood tests — Different blood tests can be used to check your cholesterol levels and for other substances that are a sign of inflammation.
  • Electrocardiogram (ECG) — This test measures the electrical activity of your heart.
  • Echocardiogram — An image of your heart made with sound waves to see how blood moves through your heart.
  • Coronary calcium scan — An image of your heart using X-rays that shows the calcium and plaque buildup in your arteries.
  • Exercise stress test — During this test, you will exercise on a treadmill or stationary bike during an ECG so doctors can see how your heart works during exercise. If you aren’t able to exercise, doctors can give you medications that simulate exercise.
  • Nuclear stress test — This test adds images to an exercise stress test by injecting a radioactive substance into your blood before you start exercising. The radioactive substance helps the coronary arteries show up in images more clearly.
  • Computerized tomography (CT) coronary angiography – This type of artery imaging test is particularly useful in low-risk patients.
  • Cardiac catheterization and angioplasty — A test where a flexible tube called a catheter is inserted into your artery to look for any blockages.

What Are the Complications of Coronary Artery Disease?

In addition to increasing your risk of a heart attack, coronary artery disease can lead to other types of heart disease, such as heart failure and an irregular heart rhythm (arrhythmia).12

Coronary artery disease can lead to heart failure by weakening the heart muscle over time.13 In heart failure in patients with coronary heart disease—most commonly caused by heart attack—your heart is too weak to pump enough blood to meet your body’s needs. The symptoms of heart failure depend on which side of the heart is affected. If the right side is affected, you may experience swelling (edema) in your arms and legs. If your left side is affected, you may experience breathlessness, coughing, and have trouble exercising.14,15

When coronary artery disease prevents your heart muscles from getting enough oxygen, it could damage the part of the heart that controls the rate and rhythm of your heart — called an arrhythmia. This can cause your heart to beat irregularly, faster, or slower. An arrhythmia can make you feel fatigued or dizzy and like your heart is pounding or racing.12

Some types of arrhythmias can also increase your risk of blood clots, which can cause a stroke if they reach your brain.12

Can You Prevent Coronary Artery Disease?

Most people should start getting screening tests for coronary artery disease starting at 20 years old. Coronary artery disease often doesn’t have any symptoms until you have a heart attack. Regular assessments by your doctor can let you know which coronary artery disease risk factors you have and help you prevent serious diseases.16

You may be able to prevent coronary artery disease with healthy lifestyle habits. Steps you can take are to:10

  • Quit smoking and avoid secondhand smoke
  • Maintain a healthy weight
  • Eat a diet low in saturated fat, trans fat, salt, and sugar
  • Eat a diet high in fiber
  • Get plenty of exercise (about 30 minutes on most days or 150 minutes per week)
  • Reduce your stress
  • Manage health conditions that increase your risk of coronary artery disease, such as high cholesterol, diabetes, and high blood pressure