Coronary artery disease


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Coronary artery disease (CAD, also called coronary heart disease, or CHD) is caused by the narrowing of the large blood vessels that supply the heart with oxygen. These are called coronary arteries. Arteries that have become extremely narrow can cause shortness of breath and chest pain during physical activity. If a coronary artery suddenly becomes completely blocked, it can result in a .

CAD can also lead to other health problems like heart failure or heart rhythm problems. Various treatments can be used to reduce the symptoms and the risk of complications.


CAD symptoms can range from shortness of breath to chest pain of varying intensity. This kind of chest pain is called angina. It is usually associated with a feeling of constriction or anxiety, and it may extend into the arms, back of the neck, back, upper abdomen or jaw. These symptoms are most often triggered by physical exertion because the heart muscle needs more oxygen then. They occur if too little blood flows through the coronary arteries. The level of physical activity at which the symptoms start to occur is also referred to as the "angina threshold."

In stable angina this threshold remains unchanged for a longer period of time. The severity of the symptoms is always about the same, too. The symptoms go away quickly with rest or after taking medicine.

Unstable angina is used to describe angina in which the symptoms become worse suddenly without any change in physical exertion, or if the threshold changes. The pain may start earlier, last longer, occur more frequently or become more intense. The very first time that angina occurs, it is also classified as unstable. Unlike stable angina, unstable angina is a medical emergency: There is a risk of because the artery may become fully blocked without any warning.

Illustration: Possible areas of pain during a heart attack – as described in the information

Possible areas of pain during a heart attack


CAD is caused by arteriosclerosis (hardening of the blood vessels). Arteriosclerosis develops from minor inflammations in the walls of blood vessels. Cells, fats and other substances stick to the walls there and form deposits. These are called plaques.

Deposits in the coronary arteries aren’t noticeable at first. If they build up over time, they may start affecting the flow of blood through the blood vessel more and more, until one part of the heart muscle doesn’t get enough oxygen. Physical activity or emotional stress can then lead to discomfort and chest pain (stable angina).

But the plaques can also suddenly break open. A blood clot may form there that blocks the blood vessel almost entirely. If this happens, the chest pain may also occur without any previous physical exertion (unstable angina). If one of the arteries is blocked completely (infarct), part of the heart muscle will die if no immediate action is taken.

Risk factors

The risk of getting coronary artery disease increases with age. Other risk factors for CAD include smoking, being very overweight, high cholesterol, high blood pressure, and diabetes.


CAD is one of the most common chronic conditions: Nearly 10% of people between the ages of 40 and 80 are affected by it – men more often than women.


CAD is a chronic disease. Someone may first notice that they have it after experiencing angina symptoms, but CAD can also cause a without any previous symptoms. Sometimes a might even go unnoticed. This is known as a silent . People who have nerve damage due to diabetes, for example, might not feel the typical symptoms of a .

The severity of angina can vary, regardless of how much the supply of oxygen to the heart muscle is affected. There are four grades of severity:

Table: Severity of stable angina
Grade Severity of symptoms
Grade 1 Chest pain only in response to sudden physical or emotional strain, but not during basic everyday activities like walking or climbing stairs.
Grade 2 Chest pain during more intense activities like walking quickly, walking uphill and climbing stairs after eating, when it is cold or when also emotionally stressed.
Grade 3 Chest pain even during low-intensity physical exertion like walking or getting dressed.
Grade 4 hest pain when at rest or during slightest physical exertion.

There is no clear cut-off point between grade 4 stable angina and unstable angina.


CAD can also lead to other health problems, most commonly heart attacks, heart rhythm problems like atrial fibrillation, and heart failure (cardiac insufficiency).

Some people who have CAD develop depression too. This is more likely following a .


Chest pain can be caused by CAD, but it may be caused by many other things too. Problems affecting the muscles or bones in the chest area are often the reason. An of the heart muscle or diseases affecting the lungs or the food pipe can also cause chest pain.

The main way to diagnose CAD is with an electrocardiogram (ECG). This test is done either while you are resting or while you are exercising. It is also possible to do an ultrasound scan of the heart (echocardiography) or use another imaging technique to examine the heart. The person’s age, other medical conditions, and the type of symptoms will determine what additional testing might be needed.

To get an idea of the risk of complications and make a treatment plan, your doctor may suggest having more tests. The typically involves:

  • Determining the risk factors: The doctor will ask about cardiovascular disease in your family, and about your lifestyle – for instance, whether you smoke and what you eat.
  • Measuring blood pressure: Blood pressure is measured because high blood pressure is a key risk factor for complications of CAD.
  • Physical examinations: Examinations such as listening to the heart or feeling the liver can help find out whether you might have other conditions such as heart failure or heart valve problems.
  • Test for metabolic disorders: Your blood might be tested to look for metabolic disorders such as type 2 diabetes. Type 2 diabetes can greatly increase the risk of developing complications.


In Germany, people covered by statutory health insurance are entitled to a general health check-up every three years from the age of 35 onwards. The aim of this check-up is to detect early signs of cardiovascular disease, diabetes and kidney problems. It involves things like having your blood pressure taken, and blood and urine tests.


The main goals of treatment for CAD are to relieve symptoms and prevent complications.

Medication can reduce the symptoms and restrictions in everyday life caused by stable angina. Beta blockers, channel blockers and nitrates are used for this purpose. If that doesn't help, doctors often try to widen the narrowed coronary artery with a procedure using a cardiac catheter. If the arteries are severely narrowed, or if several blood vessels are affected, surgery may be considered. This involves taking a blood vessel from elsewhere in the body and using it to redirect blood around the blocked coronary artery (bypassing it).

There are things you can do on your own to help prevent complications like a or heart failure: eating a healthy diet and getting enough exercise are two examples. If you smoke, you could try to give it up. Also, there are a number of different medications that can prevent complications and increase life expectancy. These include the following:

  • Low doses of acetylsalicylic acid (the drug in medicines like "Aspirin") to prevent blood clots
  • Statins to protect the blood vessels
  • Beta blockers to reduce the strain on the heart (especially in people with heart failure or high blood pressure)


People who have CAD can participate in a cardiac rehabilitation program. This aims to increase physical endurance, improve quality of life, and prevent complications.

Cardiac rehabilitation programs often include a combination of exercise, learning how to deal with the disease and risk factors, as well as psychological support. The program is directed by a team of specialists from the fields of medicine, physiotherapy, nutritional sciences and psychotherapy. Research has shown that cardiac rehabilitation that includes exercise is worth doing: It can improve quality of life and increase life expectancy.

Cardiac rehabilitation is particularly recommended if someone has had a , if CAD has already led to heart failure, or if the symptoms are greatly affecting normal everyday activities. Your doctor can help you submit an application for cardiac rehabilitation to the appropriate payer. In Germany this will typically be a statutory health insurer or pension fund.

Everyday life

Some people who have CAD may feel guilty because they think they should have done more for their health. But individual lifestyle is just one of several factors that influence your overall risk of heart disease. It can also be difficult to change basic habits once you've been diagnosed. It can sometimes help to make changes step by step.

Further information

Anyone with CAD who has statutory health insurance in Germany can participate in a structured disease management program (DMP, in German: strukturiertes Behandlungsprogramm). These programs aim to improve quality of life and ensure high-quality care. The best way to sign up for a DMP is by contacting your health insurer.

Anderson L, Thompson DR, Oldridge N, Zwisler A-D, Rees K, Martin N et al. Exercise-based cardiac rehabilitation for coronary heart disease. Cochrane Database Syst Rev 2016; (1): CD001800.

Bundesärztekammer (BÄK). Nationale Versorgungsleitlinie Chronische KHK. Langfassung. AWMF-Register-Nr.: nvl-004. February 19, 2016.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Please note that we do not provide individual advice on matters of health. You can read about where to find help and support in Germany in our information “How can I find self-help groups and information centers?

Updated on July 27, 2017
Next planned update: 2022


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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