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Cardiologists at �ٺ���Ƶ Heart are experts at diagnosing the reason for angina (chest discomfort) with no blockage, also known as ischemia with no obstructive coronary arteries (INOCA). Angina with no blockage can be caused by small artery disease (coronary microvascular dysfunction), coronary artery spasm (sometimes called Prinzmetal’s angina), or both. Our doctors carefully assess your case and determine the underlying cause of the condition using a series of advanced diagnostic tests, one of which is available at only a handful of other medical centers in the United States.

Symptoms of Angina with No Blockage

Symptoms of angina with no blockage are the same as those of heart disease due to blocked arteries: they may include pain in the chest, neck, jawline, upper stomach, or either arm; shortness of breath; nausea; vomiting; extreme fatigue; or a general sense of unease. These symptoms are sometimes brought on by exercise or emotional stress, or may happen without warning or a clear trigger. When symptoms last more than 15 minutes or are severe, it’s best to go to an emergency department to be checked for heart attack.

Causes of Angina with No Blockage

Our doctors work together to determine the underlying cause of heart symptoms with no blockage to develop a tailored treatment plan.

Coronary Artery Spasm

A sudden tightening of the muscles within the arteries that carry blood to your heart can narrow the arteries and restrict blood flow. Up to two-thirds of patients with angina with no blockage are found to have a pattern of coronary artery spasm. Coronary artery spasm can occur with or without the presence of plaque.

Small Artery Disease (Coronary Microvascular Dysfunction)

The small branches of the coronary arteries are responsible for controlling blood flow to the heart muscle. They stay partially open and then open further when the body’s demands are higher, such as when we exercise or face emotional stress. In some people, the small arteries do not have the capacity to increase blood flow enough to meet these higher demands, and there is chest discomfort because the heart is not getting enough blood at that moment.

Cholesterol Plaque

In angina with no blockage, cholesterol deposits may not fully block the artery walls but still line the wall of the entire artery. This limits blood flow, even without the presence of a spot that appears severely narrowed.

Other Conditions That Mimic Angina with No Blockage

Problems in the intestine, lungs, muscles, and bones can all cause chest discomfort. It can be difficult to identify the cause of chest discomfort because the nerves that run to the organs inside the chest are not wired to help us tell which organ is causing symptoms. This is different from the nerves that run to our fingertips, for example, which tell our brains exactly where the problem is. Heart pain can sometimes feel just like indigestion, but if the cause of chest discomfort is not obvious—as it would be if you just had a large or spicy meal—it is best to consult a healthcare provider right away.

Angina with No Blockage Diagnostic Tests

�ٺ���Ƶ is one of only a few medical centers in the United States offering advanced diagnostic tests to identify the underlying cause of angina with no blockage.

Spasm Provocation Test

In this test, the medication acetylcholine is injected into a coronary artery, while real-time imaging reveals how the artery responds. A normal response is for the artery to open further, but people who are susceptible to spasm have narrowing instead. We are one of the few medical centers in the United States to offer this test, which provides important information about vascular function and helps identify the reason for chest discomfort in people with no major blockage.

Coronary Function Testing

In this test, the medication adenosine is injected into a coronary artery, and real-time blood flow measurements are taken to show how the artery responds. In a normal response, blood flow is increased by at least two and a half times. The ratio of the blood flow to the heart after adenosine was injected compared to blood flow before medication is called the coronary flow reserve. If the coronary flow reserve is less than 2.5 and there is no major blockage by plaque, the patient has coronary microvascular dysfunction, or small artery disease. Another measurement made at the same time, called the index of microcirculatory resistance, is also used to diagnose small artery disease.

Positron Emission Tomography Stress Testing

Positron emission tomography stress testing (PET) is a noninvasive way to measure coronary flow reserve. During this test, a form of glucose labeled with radioactive material is injected intravenously. The PET scanner is equipped to detect where there is a concentration of this glucose in the body, and thus where disease may be. Some people may be given contrast materials orally or intravenously during the test as well.

Stress Cardiac Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) helps your doctor visualize blood flow to the heart. During this procedure, a magnetic field and computer are used to create clear, highly detailed images of the heart. A medication is given to open the arteries further, and the images showing blood flow are compared before and after the medication to see if all areas of the heart can receive enough blood when the heart is under stress.

You are asked to lie inside a machine that contains a strong magnet, and images of your heart are sent to a computer to be analyzed by a radiologist and your doctor.