Coronary artery disease (CAD), or coronary heart disease, develops when the coronary arteries become too narrow or cholesterol blockages develop in the walls. The coronary arteries are the blood vessels that supply oxygen and blood to the heart.

CAD tends to develop when cholesterol builds up on the artery walls, creating plaques. These plaques cause the arteries to narrow, reducing blood flow to the heart, or can cause inflammation in and hardening of the walls of the blood vessel. A clot can sometimes obstruct blood flow, causing serious health problems.

Coronary arteries form the network of blood vessels on the surface of the heart that feeds it oxygen. If these arteries narrow, the heart may not receive enough oxygen-rich blood, especially during physical activity.

CAD can sometimes lead to a heart attack. According to the Centers for Disease Control and Prevention, it is the most common type of heart disease in the United States, where it accounts for more than 655,000 deaths every year.

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CAD develops as a result of injury or damage to the inner layer of a coronary artery. This damage causes fatty deposits of plaque to build up at the injury site.

These deposits consist of cholesterol and other inflammatory products from cells. This buildup is called atherosclerosis.

If pieces of plaque break off or rupture, platelets will cluster in the area in an attempt to repair the blood vessel. This cluster can block the artery and reduce or block blood flow, which may lead to a heart attack.

Below is a 3D model of CAD, which is fully interactive.

Explore the model using your mouse pad or touchscreen to understand more about CAD.

CAD can lead to angina. This is a type of chest pain linked to heart disease.

Angina may cause the following feelings across the chest:

  • squeezing
  • pressure
  • heaviness
  • tightening
  • burning
  • aching

Angina might also cause the following symptoms:

CAD can also lead to shortness of breath. If the heart and other organs do not receive enough oxygen, any form of exertion can become very tiring, which may cause a person to pant for air. If a plaque has ruptured, it can cause shortness of breath at rest.

Complications

A heart attack occurs when the heart muscle does not have enough blood or oxygen, such as when a blood clot develops from plaque in one of the coronary arteries.

The formation of a blood clot is called coronary thrombosis. This clot, if it is big enough, can completely stop the supply of blood to the heart in that blood vessel.

Symptoms of a heart attack include:

The first symptom is usually chest pain that spreads to the neck, jaw, ears, arms, and wrists, and possibly to the shoulder blades, back, or abdomen. Symptoms can be more atypical in women.

Changing position, resting, or lying down is unlikely to bring relief. The pain is often constant but may come and go. It can last from a few minutes to several hours.

A heart attack is a medical emergency that can result in death or permanent heart damage. If a person is showing symptoms of a heart attack, it is vital to call emergency services immediately.

There is no cure for CAD. However, there are ways that a person can manage the condition.

Treatment tends to involve making positive lifestyle changes, such as quitting smoking, adopting a healthy diet, and getting regular exercise. Doctors may also prescribe medications to prevent the progression of CAD.

However, some people may need to undergo medical procedures.

Medications

Medications that people can take to reduce the risk or impact of CAD include:

  • Beta-blockers: A doctor may prescribe beta-blockers to reduce blood pressure and heart rate, especially among people who have already had a heart attack. This helps to “rest” the heart.
  • Nitroglycerin patches, sprays, or tablets: These relax the arteries and reduce the heart’s demand for blood, as well as soothe chest pain.
  • Angiotensin-converting enzyme inhibitors: These bring down blood pressure and help slow or stop the progression of CAD.
  • Calcium channel blockers: These will widen the coronary arteries, improving blood flow to the heart and reducing hypertension.
  • Statins: One 2019 review found that although taking statins cannot reduce the overall risk of death from CAD, it can prevent development and reduce the risk of non-fatal heart attacks. Statins can also cause stabilization of any plaque so that it is less likely to rupture.

Current guidelines recommend that people with a history of heart attack, stroke, angina, or other cardiovascular events take aspirin. This is because aspirin prevents blood clots from forming on plaque. For those who have not had a heart attack, the use of aspirin is more controversial. But, in general, doctors usually recommend aspirin if there is a high burden of plaque and a low risk of bleeding.

Doctors now also recommend focusing on lifestyle strategies, such as adopting a healthy diet and getting regular moderate to intense exercise. These strategies can reduce the risk of atherosclerosis.

Surgery

Surgical procedures can open or replace blocked arteries if they have become very narrow, or if a person’s symptoms are not responding to medications.

One option is coronary bypass surgery: A surgeon will use a blood vessel from another part of the body to create a graft that bypasses the blocked artery. The graft may come from the leg, for example, or an inner chest wall artery.

Another option is angioplasty and stent placement. A surgeon will insert a catheter into the narrowed part of the artery and pass a deflated balloon through the catheter to the affected area. When they inflate the balloon, it compresses the fatty deposits against the artery walls. They may leave a stent, or mesh tube, in the artery to help keep it open.

On rare occasions, a person may need a heart transplant. However, this is only if the heart has severe damage and treatment is not working.

Here, learn more about treating a heart attack.

Controlling blood cholesterol levels can help reduce a person’s risk of CAD. To better control blood cholesterol levels, consider:

  • being more physically active
  • limiting alcohol intake
  • avoiding tobacco
  • adopting a diet with less sugar, salt, and saturated fats

People who already have CAD should ensure that they control these factors by following the doctor’s recommendations.

The following factors increase a person’s risk of developing CAD:

  • having high blood pressure, or hypertension
  • having high levels of low-density lipoprotein, or “bad,” cholesterol
  • having low levels of high-density lipoprotein, or “good,” cholesterol
  • having diabetes, in which the body cannot effectively remove sugar from the bloodstream
  • having obesity
  • smoking, which increases inflammation and increases cholesterol deposits in the coronary arteries

Some risk factors are not lifestyle-related. These may include:

  • having high levels of the amino acid homocysteine, which one 2015 study linked to a higher incidence of CAD
  • having high levels of fibrinogen, a blood protein that encourages the clumping of platelets to form blood clots
  • having a family history of CAD, with early onset (before 55 years for male relatives, before 65 years for female relatives)
  • for women, having been through premature menopause
  • for men, being over 45 years of age

Having high levels of lipoprotein(a) specifically is also linked to a higher risk of cardiovascular disease and CAD.

Here, read more about how the DASH diet can reduce the risk of CHD.

A doctor can perform a physical examination, take a thorough medical history, and order a number of tests to diagnose CHD and other types of heart disease. Example of tests include:

  • Electrocardiogram: This records the electrical activity and rhythm of the heart.
  • Holter monitor: This is a portable device that a person wears under their clothes for two days or more. It records all the electrical activity of the heart, including the heartbeat.
  • Echocardiogram: This is an ultrasound scan that monitors the pumping heart. It uses sound waves to provide a video image.
  • Stress test: This may involve the use of a treadmill or medication that stresses the heart in order to test how it functions when a person is active.
  • Coronary catheterization: A specialist will inject dye through a catheter they have threaded through an artery, often in the leg or arm. The dye shows narrow spots or blockages on an X-ray.
  • CT scans: These help the doctor visualize the arteries, detect calcium within fatty deposits, and characterize any heart anomalies.
  • Nuclear ventriculography: This uses tracers, or radioactive materials, to create an image of the heart chambers. A doctor will inject the tracers into the vein. The tracers then attach to red blood cells and pass through the heart. Special cameras or scanners trace the movement of the tracers.
  • Blood tests: Doctors can run these to measure blood cholesterol levels, especially in people at risk of high blood cholesterol levels.

CAD develops when coronary arteries develop cholesterol deposits in their walls. The condition causes blockages in the arteries that feed oxygen-rich blood to the heart; the arteries also stiffen and inflammation increases.

CAD can be difficult to treat and may lead to a heart attack or stroke. However, people can take steps to reduce their risk of CAD by getting regular exercise, adopting a healthy diet, and avoiding or quitting tobacco.

People should seek immediate medical attention if they have chest pain and breathlessness, as this could indicate a heart attack.