What is coronary artery disease?

The coronary arteries are the blood vessels that carry blood to your heart.. Coronary artery disease is the narrowing or blockage of the coronary arteries. This condition is usually caused by atherosclerosis. Atherosclerosis is the build-up of cholesterol and fatty deposits (called plaques) inside the arteries. These plaques can clog the arteries or damage the arteries, which limits or stops blood flow to the heart muscle.

If the heart does not get enough blood, it cannot get the oxygen and nutrients it needs to work properly. This can cause chest pain (angina) or a heart attack.

How does plaque build up in the arteries?

CAD Plaque Buildup

Healthy coronary arteries are smooth and elastic. The inside of these muscular hollow tubes are lined with a layer of cells called the endothelium. The endothelium helps protect the vessel walls and keep the arteries working properly so blood can flow freely.

Coronary artery disease starts when you are very young. Before your teen years, the blood vessel walls start to show streaks of fat. As you get older, the fat builds up, causing minor damage to your blood vessel walls. With time, other substances that move through your blood stream, such as inflammatory cells, cellular waste products, proteins and calcium, stick to the vessel walls. These things combine with the fat and form plaque.

Plaques are different sizes, and many are soft on the inside with a hard, fibrous “cap” that covers the outside. If the hard surface cracks or tears, the soft, fatty inside is exposed. Platelets (disc-shaped particles in the blood that help form clots) move to the area, and blood clots form around the plaque. The endothelium can also become irritated and stop working properly, which causes the artery to squeeze at the wrong times. This causes the artery to narrow even more.

Sometimes, the blood clot breaks apart and blood can flow through the area again. Other times, the blood clot suddenly blocks the blood supply to the heart muscle, causing one of three serious conditions known as an acute coronary syndrome.

Collateral Circulation

Collateral Circulation
Collateral Circulation

If the blockage in a coronary artery slowly gets bigger, new blood vessels may form to reroute blood around the blockage. This is called collateral circulation. These new blood vessels may not be able to carry enough blood to the heart when you are active or under stress.

What is Ischemia?

Ischemia is described as “cramping of the heart muscle.” It is similar to a leg cramp after you exercise a long time. The muscles in the legs cramp up because they need oxygen and nutrients. Your heart, which is also a muscle, needs oxygen and nutrients to keep working. If the heart muscle can’t get enough blood because the coronary artery is too narrow, it causes ischemia. When this happens, you may feel chest pain or other symptoms.

Ischemia happens most often when the heart needs extra oxygen, such as when you are active, eating, excited, stressed or exposed to cold.

If symptoms stop within 10 minutes after you rest or take medication, you may have stable coronary artery disease (stable angina). But, the problem can get worse and you may have symptoms even when you are resting.

You may have ischemia, or even a heart attack, but not have any symptoms. This is called silent ischemia. This condition is more common in people with diabetes.

What are acute coronary syndromes?

An acute coronary syndrome is caused by a sudden blockage in the blood supply to the heart. Some people have symptoms before they have an acute coronary syndrome, but you may not have symptoms until the condition occurs. Some patients never have any symptoms. Changes caused by an acute coronary syndrome can be seen on an electrocardiogram (ECG) and in blood tests.

Unstable angina: This may be a new symptom or can happen if you have stable angina that changes to unstable angina. You may start to have angina more often, when you are resting, or it may be worse or last longer. The condition can lead to a heart attack. If you have unstable angina, you will need medication, such as nitroglycerin or a procedure to correct the problem.

Non-ST segment elevation myocardial infarction (NSTEMI): This is a type of heart attack (MI) that does not cause major changes on an ECG. But, a blood test will show that there is damage to your heart muscle. The damage is usually minor since the blockage that causes an NSTEMI is often small or temporary.

ST segment elevation myocardial infarction (STEMI): This type of heart attack (MI) is caused by a sudden blockage of the blood supply to the heart.

If you have an acute coronary syndrome, call 911!

What are the symptoms of coronary artery disease?

The most common ++symptom of coronary artery disease++ is angina. Angina is chest pain and can also be described as chest discomfort, heaviness, tightness, pressure, aching, burning, numbness, fullness, or squeezing. It can be mistaken for indigestion or heartburn. Angina is usually felt in the chest, but you may also feel it in your left shoulder, arms, neck, back or jaw.Other symptoms of coronary artery disease include:

  • Shortness of breath
  • Heart palpitations: irregular heartbeats, skipped beats or a “flip-flop” feeling in your chest
  • A faster-than-normal heartbeat
  • Dizziness
  • Nausea
  • Extreme weakness
  • Sweating

What should I do if I have symptoms of coronary artery disease?

Do not wait to get help; Time is Muscle!

At the first signs of a heart attack, call 911. Do not wait for your symptoms to “go away.” Every minute you spend without treatment increases your risk of long-term heart damage. Get to the hospital, even if you are not 100% sure you are having a heart attack!

Call 911 Emergency

If the symptoms last longer than 5 minutes, CALL 911!

If the symptoms go away in 5 minutes and are new, worse or happening more often, call your doctor.

If You Have a Prescription for Nitroglycerin

If you have symptoms of angina and you have a prescription for nitroglycerin, stop what you are doing and rest. Take one dose (dissolve one tablet under your tongue or spray under your tongue). Wait 5 minutes. If you still have symptoms, call 911.

If you have chronic stable angina and you have symptoms, take one dose of nitroglycerin. Wait 5 minutes. If symptoms continue, take another dose. You can take 3 doses within 15 minutes. If symptoms continue after 3 doses, call 911.

Symptoms in women

Women can have different symptoms of coronary artery disease than men do. For example, many women who have a heart attack have:

  • Pain or discomfort in the chest, left arm or back
  • A very fast heartbeat
  • Shortness of breath
  • Nausea or fatigue

If you have any of these symptoms, get medical help right away. Call 911 or have someone take you to the nearest emergency room. Do not wait!

How is angina different from a heart attack?

The symptoms of a heart attack (myocardial infarction/MI) are similar to angina. But, angina is a warning symptom of heart disease, not a heart attack.

AnginaHeart Attack
Caused by a drop in blood supply to the heart due to the gradual build-up of blockage in the arteries.Caused by a sudden lack of blood supply to the heart muscle. The blockage is often due to a clot in a coronary artery.
Does not cause permanent damage to the heart.Can cause permanent damage to the heart muscle.
Symptoms last a few minutes and usually stop if you rest or take medication. You may have chest pain or discomfort, shortness of breath, palpitations, fast heartbeat, dizziness, nausea, extreme weakness and sweating. Symptoms are often triggered by strenuous activity, stress, eating or being in the cold.Symptoms usually last more than a few minutes and can come and go, and do not completely go away after taking nitroglycerin. Symptoms include chest pain or discomfort; pain or discomfort in other areas of the upper body; trouble breathing or shortness of breath; sweating or “cold” sweat; feeling full, like you are choking or indigestion; nausea or vomiting; lightheadedness; extreme weakness; anxiety; fast or irregular heartbeat.
Emergency medical attention is not needed. Call your doctor if you have not had symptoms before or if your symptoms have gotten worse or happen more often.Emergency medical attention is needed if symptoms last longer than 5 minutes.

Reviewed by a Cleveland Clinic medical professional.

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