How Is Coronary Microvascular Disease Diagnosed?

First, your doctor will take your medical history and do a physical exam to diagnose coronary microvascular disease (MVD). The doctor will check to see if you have any risk factors for heart disease. You will be weighed to check for obesity, and your cholesterol will be tested. You also will be tested for metabolic syndrome and diabetes.

Your doctor may ask you to describe any chest pain, including when it started and how it changed during physical activity or periods of stress.

Other symptoms such as fatigue (tiredness), lack of energy, and shortness of breath will be noted. Women will be asked about their menopausal status. Your doctor may order blood tests, including a test for anemia.

Specialists Involved

Doctors who diagnose and treat coronary MVD are most often specialists in cardiology (heart disease), family medicine, and internal medicine.

Diagnostic Tests

The risk factors for traditional coronary artery disease (CAD) and coronary MVD are often the same. Therefore, your doctor will use tests to help show if you have traditional CAD. These tests may include:

• Coronary angiography (an-jee-OG-ra-fee). This test is a special x-ray exam of the heart and blood vessels. It shows plaque buildup in the large coronary arteries. This test is often done during a heart attack to help locate blockages.
• A stress test. This test provides your doctor with information about blood flow through the coronary arteries to your heart muscle during physical stress. During stress testing, you exercise (or are given medicine if you're unable to exercise) to make your heart work hard and beat fast while heart tests, such as nuclear heart scanning and echocardiography, are performed. If coronary angiography doesn't show plaque buildup in the large coronary arteries, a stress test may still show abnormal blood flow. This may be a sign of coronary MVD.
• A magnetic resonance imaging (MRI) cardiac stress test. This test is being used more widely to evaluate women with chest pain.

Unfortunately, standard tests for CAD don't always detect heart disease in women. Standard tests look for blockages that affect blood flow in the large coronary arteries. However, the WISE Study showed that, in women, damage to the heart's smallest coronary arteries may affect blood flow.

This damage occurs when plaque forms in arteries, when the arteries spasm (tighten), or when the walls of the arteries are damaged or diseased.

In coronary MVD, plaque can scatter, spread out evenly, or build up into blockages in the tiny coronary arteries. Plaque narrows the coronary arteries and reduces blood flow to the heart muscle.

Spasms of the small coronary arteries prevent enough oxygen-rich blood from moving through the arteries.

Changes in the arteries' cells and the surrounding muscle tissues may, over time, damage the arteries' walls.

The standard tests for CAD can't detect these types of problems in the tiny coronary arteries. Therefore, standard tests may show that a woman doesn't have heart disease, even if she does. (Fifty percent of women who have the standard CAD tests show normal coronary arteries compared to 17 percent of men.)

If test results show you don't have CAD, you can still be diagnosed with coronary MVD if evidence shows that not enough oxygen is reaching the small arteries in your heart.

Since symptoms of coronary MVD often first appear during routine daily tasks, you may be asked to fill out a questionnaire called the Duke Activity Status Index (DASI). The questionnaire will ask you how well you're able to do daily activities such as shopping, cooking, and going to work. The results of this survey will help doctors decide on the kind of stress test you should have. It will also give them some information about how well the blood is flowing through your coronary arteries.

Research continues to improve ways to detect and diagnose heart disease caused by coronary MVD.