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Coronary Microvascular Disease
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Coronary Microvascular Disease (CMD)
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Related terms: angina, cardiac syndrome X, CMD, MVD, microvascular angina

Coronary Microvascular Disease (CMD or MVD) is a type of heart disease that affects the small blood vessels of the heart. CMD patients may experience the pain of angina similar to those with coronary artery disease (CAD); however, in CMD, the coronary arteries are clear of blockages. 

Microvascular disease damages the tiny blood vessels in the heart, causing them to narrow, tighten or constrict (spasm). That reduces blood flow in the cardiovascular system.  

CMD occurs more frequently in women (young women in particular) and the disease puts you at risk for heart attacks.

What are the symptoms?

The chest pain (microvascular angina) you experience with CMD can last as long as 10 to 30 minutes and can spread to your left arm, neck, back, throat, or jaw. You may have numbness or a loss of feeling in your arms, shoulders, or wrists.

Other symptoms can include: 

  • Shortness of breath 
  • Sleep problems 
  • Fatigue 
  • Lack of energy 

Although these symptoms are similar to those from coronary artery disease, if you have CMD, they occur more often during routine daily activities and times of mental stress than during physical exertion.

If you have microvascular disease, you are at risk for heart attack, so if your "usual" symptoms change or increase, that may be a warning sign of a heart attack and you should get medical help immediately.

What causes CMD?

New research has shown that CMD may be caused by plaque that spreads evenly throughout the arteries, resulting in damaged small blood vessels that restrict proper blood flow.

Other factors being studied (particularly in women) include lower than normal estrogen levels and anemia. 

Men and women who have CMD often have diabetes, high blood pressure, or a family history of cardiomyopathy. 

As with any heart disease, it is important to manage as many of these common risk factors as possible: 

How is CMD diagnosed?

Diagnosing CMD is challenging because many of the standard tests are designed to detect coronary artery disease (for example, blocked arteries). 

Current research is looking at better ways to diagnose and treat microvascular disease (especially in women). Coronary microvascular disease is diagnosed by using some of these tests:

  • A baseline electrocardiogram (ECG or EKG), which records your heart's electrical activity while you sit quietly. An exercise ECG, also known as a stress test, will show how your heart responds to increasing exercise. 
  • An exercise radioisotopic test, also called a nuclear stress test, to show how blood flows through your arteries.
  • Echocardiography, which uses sound waves to produce an image of the heart to see how it is working.

In patients with CAD, coronary angiography usually shows a blocked artery that slows blood flow to the heart. But in patients with CMD, the test results are completely normal. If you have an abnormal exercise stress test and a normal coronary angiogram, your doctor may suspect that you have CMD.

A discussion of your symptoms (if any), questions about your daily routine, and additional blood tests are all ways to help diagnose different forms of heart disease. 

How is CMD treated?

A number of medicines can help relieve the angina pain that comes with microvascular disease.

  • A medicine called nitroglycerin (nitro) can widen or dilate the arteries and improve blood flow to your heart. Nitro can be given through a skin patch, pills, an ointment, or a spray.
  • Beta-blockers "block" the chemical or hormonal messages sent to your heart that make it work harder. 
  • Calcium channel blockers can help to keep your arteries open and reduce your blood pressure by relaxing the smooth muscle that surrounds the arteries in your body.
In discussions with your doctor, you may need to try a number of these medicines before you find the one that works best for you.

Additional treatments are focused on controlling risk factors and other symptoms.

  • Lifestyle changes such as a heart-healthy diet, quitting smoking, being physically active, managing stress
  • Medications to manage cholesterol, blood pressure, diabetes

See also on this site:

See on other sites: 

National Heart, Lung, and Blood Institute 
What is Coronary Microvascular Disease? (CMD) 

American Heart Association 
Coronary Microvascular Disease (MVD)

Updated September 2015

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