Diagnosing Coronary Artery Disease

At NYU Langone, specialists diagnose and manage coronary artery disease, which is estimated to affect more than 13 million Americans. The coronary arteries deliver oxygen-rich blood from the aorta, the body’s largest artery, to the heart’s four chambers. Coronary artery disease is caused by a buildup of plaque—a waxy substance composed of cholesterol, calcium, and fat—in these arteries. This is known as atherosclerosis, and it can lead to decreased blood flow and a heart attack.

The most common symptom of coronary artery disease is angina, or chest pain, which occurs when the heart does not receive enough blood. It may cause discomfort in the arms, back, jaw, neck, shoulders or abdomen, or both. Other symptoms include shortness of breath, cold sweats, lightheadedness, and nausea. Sometimes, angina can feel like indigestion. 

Women may experience angina or heart attack symptoms differently than men. Although women may have chest discomfort, they are more likely to have jaw, neck, shoulder, and upper back pain; fatigue; and nausea. They may also have shortness of breath. 

For some people, the first sign of coronary artery disease is a heart attack, which occurs when a coronary artery is completely blocked. Because there may be no symptoms until the late stages of plaque buildup, it is never too early to take steps to help prevent coronary artery disease and its related complications, such as heart attack and stroke.

Some people with coronary artery disease are diagnosed with ischemia, a reduction in the blood flow to the heart that occurs during exertion. It’s caused by narrowed arteries in the heart. NYU Langone is leading an international clinical trial to test the effectiveness of treatments for ischemia in people with coronary artery disease.

Diagnostic Tests

Your NYU Langone cardiologist takes a family and medical history to determine your risk for coronary artery disease. Next, he or she performs a physical exam, asks whether you smoke and how much you exercise, asks about your diet, and determines if you have diabetes, high blood pressure, or unhealthy cholesterol levels. Your doctor also orders tests to help diagnose coronary artery disease.

Blood Tests

Your doctor may take a sample of blood to check the levels of different substances, including cholesterol; triglycerides, or fat in the blood, which can increase the risk of coronary artery disease; proteins that can indicate inflammation in the arteries; and glucose, or sugar, which can help determine if you have diabetes. Elevated levels of these substances can increase your risk for atherosclerosis.

Electrocardiogram

An electrocardiogram, or EKG, records electrical signals from your heart. It can show whether you have had or are having a heart attack. Small, sticky metal electrodes are placed on your chest, wrists, and ankles, and information about your heart is sent to a machine, which prints out a graph for the doctor to analyze. 

Coronary Calcium Scan

Also called cardiac calcium scoring, this type of CT scan enables a doctor to check the walls of the arteries for calcium buildup, a sign of coronary artery disease. A CT scan uses X-rays and a computer to create cross-sectional images of the body. If calcium is found in the coronary arteries, it may indicate coronary artery disease. 

CT Coronary Angiogram

A CT coronary angiogram can reveal plaque buildup and identify blockages in the arteries, which can lead to a heart attack. Prior to the test, a contrast dye is injected into the arm to make the arteries more visible. The test typically takes 30 minutes to complete. 

Coronary Catheterization and Angiogram

In this test, which is performed in the hospital, doctors use X-rays taken in real time to create images of the coronary arteries. They can help identify any blockages. 

After you’re given local anesthesia and a sedative, your doctor guides a thin, hollow tube called a catheter through a tiny incision in the arm or groin to an artery that leads to the heart. 

A cardiologist injects a contrast agent, or dye, into the catheter to highlight any blockages. This is called an angiogram. The physician performing the procedure explains what your arteries look like and what therapies, if any, are needed.

The procedure takes 30 to 40 minutes. Afterward, the catheter is removed and the incision is closed. 

Doctors may also use a coronary catheterization and angiogram to assess your heart and arteries prior to surgery.

Stress Tests

Your doctor may order a stress test to check the function of your heart and arteries.

An abnormal result can indicate a reduction in blood flow to the heart during exertion—called ischemia—that’s typically caused by a blockage in the heart arteries. NYU Langone is currently involved in a clinical trial to determine the effectiveness of treatments for this condition. Your doctor can determine if you are eligible to participate.

There are several different types.

Exercise Stress Test

For people who are able to exercise, an exercise stress test helps your doctor determine whether your heart receives enough blood and oxygen during activity. It also reveals how the heart responds to exercise.

During this test, a doctor performs an electrocardiogram, or EKG, in which small electrodes are placed on your chest, wrists, and ankles. The electrodes send information about your heart’s rate and rhythm to a machine while you walk on a treadmill at increasing levels of difficulty. Your blood pressure is measured with a blood pressure cuff wrapped around your upper arm. 

Pharmacologic Stress Test

If you are unable to complete the exercise stress test, your doctor may prescribe a pharmacologic stress test. In this test, medication is injected into an arm. It causes the heart’s blood vessels to dilate, or widen, depending on the medication your doctor chooses. If a person has blocked arteries, they won’t dilate, and blood is diverted to widened areas of the arteries. Other medications may be used to cause the heart to pump faster, simulating exercise. 

A cardiac imaging test is used before and after the medication is given to show how the heart reacts under stress. This enables the doctor to identify coronary artery disease. 

Nuclear Stress Test

In this test, which can be part of an exercise or pharmacologic stress test, a small amount of radioactive tracer is injected into a vein in the arm. Small electrodes are placed on your chest, wrists, and ankles to measure your heart rate. A device called a gamma camera detects the radiation released by the tracer and takes images of your heart from a machine above your body while you lie down. It produces images of the heart at rest. 

Next, you have an exercise or pharmacologic stress test. After at least 20 minutes, you lie under the gamma camera for post-exercise imaging. The images are compared to allow your doctor to diagnose coronary artery disease.

Echo Stress Test

In this ultrasound test, also known as an echocardiogram, sound waves are used to create images of the heart. It can reveal how well the heart is pumping blood. Your doctor can identify any areas where blood isn’t flowing properly. 

During the test, a technician rubs a warm gel on your chest and places a handheld device called a transducer on your skin. The transducer sends images of your heart to a computer monitor. No radiation is used.

This test can be done before and after an exercise or pharmacologic stress test.

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