Coronary artery disease (CAD), also called coronary heart disease, is the most common type of heart disease. CAD occurs when your heart’s arteries can’t carry necessary oxygen and nutrients to itself. This is typically because the arteries are damaged, diseased, or blocked, all of which can disrupt the blood flow.

The most frequent cause of CAD is injury and plaque buildup in these vessels, which are called coronary arteries. When your arteries narrow, it leaves less space for blood to flow. This decreases blood flow and makes it difficult for your body to supply your heart with the blood it needs. A lack of blood flow can cause chest pain, shortness of breath, and other symptoms of cardiac disease.

Plaque usually builds up over many years. For some people, the first sign of CAD may be a heart attack. In the United States, heart disease is the leading cause of death, with CAD being the most common type of heart disease.

Heart disease is one type of cardiovascular disease. Per the World Health Organization (WHO), cardiovascular diseases are the number one cause of death worldwide.

Understanding the different causes of CAD may help you reduce your risk of developing it later on. If your doctor diagnoses you with CAD early on, you may be able to prevent or reduce the risk of CAD by making lifestyle changes. Read more about how to identify the symptoms of coronary artery disease here.

Atherosclerosis, which involves the clogging and hardening of arteries, is the number one cause of CAD.

Atherosclerosis

Healthy coronary arteries have smooth walls through which blood can easily flow. When there’s damage to an artery wall, plaque gets trapped in those crevices inside the artery lumen. Plaque deposits are made of fats, cholesterols, inflammatory cells, and calcium. Over time, the plaque on those walls hardens and restricts blood flow. This process is called atherosclerosis.

Other substances traveling through your arteries, such as proteins and cellular waste products, can also stick to the plaque. It usually takes years for the buildup to become noticeable. Often, you won’t know you have plaque buildup until it becomes bad enough to cause serious symptoms.

Plaque buildup can lead to reduced blood flow to the heart. This can cause:

  • chest pain or discomfort (angina)
  • severe blockage, which prevents your heart from receiving enough blood
  • weak heart muscle
  • heart failure

Atherosclerosis is thought to happen in areas of the arteries that have turbulence, with unsteady and swirling blood flow, but other factors such as hypertension (high blood pressure), infections, and chemicals can damage the artery walls.

While some buildup is the result of aging, other factors can increase the rate at which atherosclerosis occurs. This includes:

  • smoking (because tobacco chemicals irritate the artery walls and adversely affect the functioning of the cardiovascular system)
  • high levels of fat (such as triglycerides) in the blood
  • high levels of cholesterol in the blood
  • diabetes mellitus
  • hypertension

Other causes that limit blood flow

There are rare causes of damage or blockage to a coronary artery that can also limit blood flow to the heart. These causes, which are typically related to atherosclerosis, are:

  • an embolism (a piece of blood clot that has broken off and can cause blockage downstream in a blood vessel)
  • an aneurysm (an abnormally dilated segment of a blood vessel)
  • artery vasculitis (the inflammation of an artery)
  • a spontaneous coronary artery dissection (when there is a tear through the inner layer of the coronary artery, where blood flows in between the layers of the coronary artery wall, instead of the true lumen of the artery)

Sometimes, plaques burst open and cause the blood cells that form clots (called “platelets”) to rush into the artery around the plaque. This then causes blood clots and further luminal narrowing. These blood clots can become large enough to block arterial blood flow to your heart, which leads to a heart attack.

In the event of a heart attack, your heart muscle will start to die within the territory downstream from the blocked coronary artery.

The risk factors for CAD are the same as those for atherosclerosis.

Other common factors that increase your risk are:

  • age (people over 65 at a heightened risk)
  • sex (men at a higher risk than women until age 70)
  • family history of the disease
  • being overweight
  • obesity
  • uncontrolled diabetes mellitus, especially type 2 but also type 1
  • lack of physical activity
  • smoking tobacco
  • continuous stress
  • excessive alcohol consumption

Men develop CAD earlier than women because women are protected by high levels of estrogen until menopause. But among people 75 years old and older, women are just as likely or more likely to die from CAD as men.

A poor diet, especially one that’s high in fat and low in vitamins (such as C, D, and E) can also increase your risk.

High levels of C-reactive protein (CRP) may also be evidence of plaque instability and inflammation. While it’s not tied directly to CAD, it can be a predictor of risk for issues with ischemia caused by CAD, according to the Merck Manual.

Because CAD and atherosclerosis may not show symptoms, your doctor may perform extra tests to confirm the diagnosis.

These tests include:

  • electrocardiogram, called EKG for short, to measure your heart’s electrical activity
  • echocardiogram to get an ultrasound-derived picture of your heart
  • stress test to measure your heart’s reaction while it’s at work
  • chest X-ray to see a radiographic picture of your heart, lungs, and other chest structures
  • left heart (cardiac) catheterization with angiogram imaging to check your arteries for blockage
  • CT scan of the heart to look for calcifications in the coronary arteries

Find out how these tests help determine a diagnosis for CAD. Your treatment will depend on your diagnosis.

You can make many lifestyle changes to decrease your risk of developing CAD and its complications.

Eating a healthy diet and reducing your salt intake is a great way to prevent CAD. Other means of prevention include:

  • losing weight if you’re overweight
  • increasing your physical activity
  • controlling high blood pressure
  • controlling diabetes mellitus
  • controlling high cholesterol

If you smoke tobacco products, quitting helps prevent the development of CAD. If you already have a severe blockage, surgical procedures can help restore blood flow to the heart.

Medications

Your doctor may prescribe or recommend daily preventive medications, such as aspirin or other cardiac medications, if lifestyle changes aren’t enough. Aspirin can help prevent CAD by stopping platelet blood cells from clumping and contributing to plaques.

But the type of drug you take depends on your risk factors. For example, if your blood clots too easily, causing you to have dangerous blood clots, you may need to take an anticoagulant, such as warfarin.

Your doctor might prescribe gemfibrozil (Lopid) if you have too high of a triglyceride level in your bloodstream. If your LDL cholesterol level is too high in your bloodstream, you may be given a prescription for a statin, such as rosuvastatin (Crestor).

Look at the graph below of common drugs used to treat CAD and their prices.

The goal of your treatment is to improve blood flow, prevent or delay the buildup of plaque in your coronary arteries, and make it easier for your heart to pump blood.