How is coronary artery disease (CAD) diagnosed?

The appropriate use of imaging tests to diagnose coronary artery disease (CAD) depends on the situation. For apparently well people without heart symptoms, I do not favor the use of any imaging test for screening for CAD.

For individuals with symptoms suggestive of CAD, a stress test monitored by electrocardiogram is often a good place to start. For those without symptoms but at high risk for CAD based on non-imaging markers, imaging tests may provide useful information for management. You should discuss with your cardiologist about whether you fit into this category.

Computed tomographic angiography of the heart (coronary CTA) is evolving rapidly and may become part of routine practice in those with symptoms, elevated calculated risk, or a positive stress test. Currently, the level of radiation is on the same order as a cardiac catheterization with traditional invasive angiography. Technical advances are rapidly lowering the amount of radiation required for coronary CTA. Even so, such tests should not be used for routine surveillance on a repetitive basis.

Coronary artery disease (CAD) can usually be diagnosed based on a person's medical history, risk factors, a physical exam, and the results from tests and procedures. There is no one test that can diagnose coronary artery disease, so the doctor may recommend one or more of the following:
  • electrocardiogram (EKG)
  • stress test
  • echocardiogram (echo)
  • chest x-ray
  • blood tests
  • coronary angiography
  • cardiac catheterization
This content originally appeared online in "The Patient Guide to Heart, Lung, and Esophageal Surgery" from the Society of Thoracic Surgery.

There are multiple ways a doctor can test for coronary artery disease, including the symptoms that a patient presents with such as chest pain, shortness of breath, lightheadedness, pressure in the chest or arms, nausea, vomiting, neck pain, jaw pain, treadmill testing, stress echos, multiple perfusion imaging, CRP, CT scanning of the arteries of the heart to look at the calcium content, and CT angiography with contrast dye. In addition doctors will examine the carotid arteries with ultrasound to see if the patient is making plaque in the carotid arteries feeding the brain. If this is the case, it can help him be more aggressive in the search for coronary disease involving the heart. There are other tests that are more invasive such as cardiac catheterization to actually look at the plaque in the heart and intracoronary ultrasound, which actually allows us to see the plaque inside the artery with ultrasound.

This is important in order to try to stabilize the arteries and prevent the patient from having heart attack. Each test is an addition to the symptoms that the patient presents with and the evaluation will include multiple tests to give the doctor the best picture of whether the patient actually as coronary disease.

Dr. Sameer A. Sayeed, MD
Cardiologist (Heart Specialist)

Coronary artery disease may be diagnosed in several ways. The least invasive methods include a stress test with EKG monitoring where there is about 60-70% accuracy. Stress testing with echocardiography or nuclear imaging has about 80-95% accuracy and is also non-invasive. Coronary CT imaging and MRI also have similar accuracy and are also non-invasive. The gold standard for diagnosis is still cardiac catheterization but this is an invasive procedure.

Doctors can determine your risk for CAD by checking your blood pressure, cholesterol and blood glucose, and by finding out more about your family's history of heart disease. If you're at high risk or already have symptoms, your doctor can perform several tests to diagnose CAD, including ECD or EKG (electrocardiogram), echocardiogram, exercise stress test, chest X-ray, cardiac catheterization and coronary angiogram.

Dr. John J. Marshall, MD
Cardiologist (Heart Specialist)

To determine whether you have coronary artery disease, and how severe it is, your doctor will talk with you about your health, lifestyle and family history. This information, plus the results of a physical examination and blood tests will help determine whether you have risk factors for heart disease.

Your doctor may also want you to have certain diagnostic tests, including one or more of the following:

  • electrocardiogram, which measures electrical activity in your heart;
  • a stress test, which measures your heart’s ability to tolerate exercise  and may include an imaging test as well; and
  • cardiac catheterization (also known as coronary angiography) or computed tomography, both of which allow your doctor to see images of your arteries and any build up of artery-clogging plaque.

A risk of coronary artery disease can be diagnosed through routine checkups. A blood test can indicate high levels of cholesterol. A check of blood pressure can reveal unhealthy levels. The presence of common symptoms such as chest pain or shortness of breath can also point to the presence of the condition. If any or all of these risk factors are present, further tests of the heart can confirm the diagnosis.

The gold standard for the diagnosis of coronary artery disease is the coronary angiogram, a term often used synonymously with cardiac catheterization.

During this procedure, which is performed in the cardiac catheterization laboratory, a tube or catheter is inserted into a blood vessel (usually in the groin), and is guided to the heart with the assistance of x-ray imaging. Dye is then introduced into the coronary arteries to detect blockages, and digital cine films (angiograms) are recorded and analyzed.

If the heart muscle cannot get enough oxygen—a state known as myocardial ischemia—symptoms such as chest pain (angina) or shortness of breath may result.

A presumptive diagnosis of coronary disease is based on a review of symptoms, health history, an electrocardiogram, and an exercise stress test, perhaps with a thallium scan. A more definitive diagnosis requires cardiac catheterization and angiography.

During an exercise stress test, the patient is hooked up to an electrocardiographic monitor (an EKG machine) and then asked to walk on a treadmill, peddle a stationary bicycle, or climb steps. The EKG monitor will show whether the heart muscle is getting enough blood. An exercise test also detects silent ischemia, a condition with no symptoms in which the heart muscle does not get enough blood.

If severe narrowing is suspected, a coronary angiogram may be needed. This examination entails threading a catheter through a blood vessel into the heart, and then injecting a dye into the coronary arteries to make them visible on x-rays.

Dr. Claudio M. Smuclovisky, MD
Diagnostic Radiologist

Some people undergo stress testing with their doctor to check for coronary artery disease. The stress test, however, catches later stages of coronary artery disease when there is already blockage in the arteries and decreased oxygen in the muscle of the heart. Cardiac computed tomography angiography (CTA or Cardiac CT) is a state-of-the-art diagnostic test that can detect heart disease years before it's detectable by stress tests.

An EKG can be very useful for a doctor to notice when the blood supply is constricted. Still, an EKG in someone with a history of Coronary Artery Disease and angina often has a "normal" reading.

Because a resting EKG often produces a "normal" reading for someone with angina, doctors may need to perform a stress test to evaluate the presence of Coronary Artery Disease. If characteristic signs occur during stress testing, especially if typical chest pains occur, the test is considered "positive".

A cardiac catheterization test can determine if Coronary Artery Disease is present, how severe it is and if a coronary artery bypass graft is needed. The catheterization test can definitely exclude Coronary Artery Disease if it is not present.

A doctor will perform the test if:

  • angina is being treated by a doctor by the symptoms continue
  • severe blood flow restriction is present on a stress test and symptoms suggest Coronary Artery Disease, yet the doctor is not able to come to a definitive diagnosis with other tests
  • a patient has many hospital admissions for chest pain where a heart attack is ruled out but the presence of Coronary Artery Disease has not been determined

During cardiac catheterization, blockages are treated by a balloon that is blown up inside the coronary arteries, forcing open the passage. This procedure is Percutaneous Transluminal Coronary Angioplasty - or just plain angioplasty.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.