Coronary Microvascular Disease (MVD)

What is coronary microvascular disease?

Coronary microvascular disease (sometimes called small artery disease or small vessel disease) is heart disease that affects the walls and inner lining of tiny coronary artery blood vessels that branch off from the larger coronary arteries. Coronary heart disease (CHD), also called coronary artery disease, involves plaque formation that can block blood flow to the heart muscle. In coronary MVD, the heart's coronary artery blood vessels don't have plaque, but damage to the inner walls of the blood vessels can lead to spasms and decrease blood flow to the heart muscle. In addition, abnormalities in smaller arteries that branch off of the main coronary arteries may also contribute to coronary MVD.

See an illustration of coronary arteries.

Women more frequently develop coronary microvascular disease and it occurs particularly in younger women. The risk factors for coronary MVD are the same as for coronary artery disease, including diabetes, high blood pressure and high cholesterol.

Diagnosing coronary MVD was previously a challenge. PET scans and other types of imaging are now available which measure blood flow through the coronary arteries and can detect coronary MVD in very small blood vessels.

According to the National Heart, Lung, and Blood Institute's WISE-R study(link opens in new window) (Women's Ischemia Syndrome Evaluation), research is ongoing to learn more about the role of hormones in heart disease and to find better ways to diagnose coronary MVD.

Other names for coronary microvascular disease

• Cardiac syndrome X
• Nonobstructive coronary heart disease

What causes coronary microvascular disease?

Many researchers think some of the risk factors that cause atherosclerosis may also lead to coronary MVD. Atherosclerosis is a disease in which plaque builds up inside the arteries.

Risk factors for atherosclerosis include:

• Unhealthy blood cholesterol levels
• High blood pressure
• Smoking
• Diabetes
• Overweight and obesity
• Lack of physical activity
• Unhealthy diet
• Older age
• Family history of heart disease

Understand your risk for coronary microvascular disease

Women may be at risk for coronary MVD if they have lower than normal estrogen levels at any point in their adult lives. Low estrogen levels before menopause can raise younger women's risk for coronary MVD and can be caused by stress and a functioning problem with the ovaries.

Women who have high blood pressure before menopause, especially high systolic blood pressure, are at increased risk for coronary MVD. Women who experience intense or irregular menopause symptoms also may be more likely to develop heart issues. After menopause, women tend to have more of the traditional risk factors for atherosclerosis, which may also put them at higher risk for coronary MVD.

People who have heart disease are more likely to have a worse outcome, such as a heart attack, if they also have anemia. This is because anemia is thought to slow the growth of cells needed to repair damaged blood vessels.

What are the signs and symptoms of coronary microvascular disease?

Women with coronary MVD often have chest pain called angina, also called microvascular angina. They may experience prolonged angina, and may also have angina when at rest. 

Other signs and symptoms of coronary MVD are:

• shortness of breath
• sleep problems
• fatigue
• lack of energy

People who experience coronary MVD symptoms often first notice them during their routine daily activities and times of mental stress. They occur less often during physical activity or exertion. This differs from disease of the major coronary arteries and main branches, in which symptoms usually first appear during physical activity. If you have coronary MVD, learn the warning signs of a heart attack and the warning signs of a heart attack in women.

Diagnosis of Coronary Microvascular Disease

Your doctor or other health care professional will diagnose coronary MVD based on your medical history, a physical exam and test results. You will also be evaluated for any risk factors for heart disease including high cholesterol, metabolic syndrome, diabetes and being overweight or obese.

Diagnostic Tests

The risk factors for coronary MVD and traditional heart disease often are the same. Some recommend tests for heart disease include:

• Coronary angiography (PDF)
• Stress test
• Coronary magnetic resonance (CMR) imaging

Standard tests for CHD may not be able to detect coronary MVD. These tests look for blockages in the large coronary arteries. Coronary MVD affects the tiny coronary arteries. If you have angina but tests show your coronary arteries are normal, you could still have coronary MVD. Additional testing can confirm the diagnosis.

Coronary MVD symptoms often first occur during routine daily tasks. Because of this, you may be asked to fill out a questionnaire called the Duke Activity Status Index (DASI). The DASI includes questions about how well you're able to do daily activities, such as shopping, cooking and going to work.

The DASI results can help determine what additional tests are needed to make the diagnosis of coronary MVD.

Duke Activity Status Index (DASI)

The Duke Activity Status Index is a self-administered questionnaire that measures a person's functional capacity. It can be used to get a rough estimate of peak oxygen uptake.

1. Can you take care of yourself (eating, dressing, bathing or using the toilet)?
2. Can you walk indoors, such as around your house?
3. Can you walk a block or two on level ground?
4. Can you climb a flight of stairs or walk up a hill?
5. Can you run a short distance?
6. Can you do light work around the house, such as dusting or washing dishes?
7. Can you do moderate work around the house, such as vacuuming, sweeping floors or carrying in groceries?
8. Can you do heavy work around the house, such as scrubbing floors or lifting and moving heavy furniture?
9. Can you do yard work, such as raking leaves, weeding or pushing a power mower?
10. Can you have sexual relations?
11. Can you participate in moderate recreational activities, such as golf, bowling, dancing, doubles tennis or throwing a baseball or football?
12. Can you participate in strenuous sports, such as swimming, singles tennis, football, basketball or skiing?

Duke Activity Status Index (DASI) = sum of “Yes” replies ___________

VO₂peak = (0.43 x DASI) + 9.6

VO₂peak = ___________ ml/kg/min ÷ 3.5 ml/kg/min = __________ METS

You may also be tested for anemia. Anemia is thought to slow the growth of cells needed to repair damaged blood vessels.

Research to identify better ways to detect and diagnose coronary MVD is ongoing.

Treatment of Coronary Microvascular Disease

Relieving pain is one of the main goals of treating coronary MVD. Treatments also are used to control risk factors and other symptoms.

Treatments may include medicines such as:

• Cholesterol medication to improve cholesterol levels.
• Blood pressure medications to lower high blood pressure and decrease the heart's workload.
• Antiplatelet medication to help prevent blood clots.
• Medications to relax blood vessels including beta blockers, calcium channel blockers and nitroglycerin.
• Nitroglycerin to treat chest pain.

Prevention of Coronary Microvascular Disease

No studies have been done on how to prevent coronary MVD. Researchers don't yet know how or in what way preventing coronary MVD differs from preventing heart disease.

Knowing your family history of heart disease, making the following lifestyle changes and ongoing care can help you lower your risk for heart disease.

• Manage blood pressure
• Control cholesterol
• Reduce blood sugar
• Get active
• Eat better
• Lose or manage weight
• Stop smoking 

If lifestyle changes aren't enough, your doctor may prescribe medicines to control your risk factors. Take all of your medicines as prescribed.