Coronary Microvascular Disease

Coronary microvascular disease (CMD) is a difficult to diagnose form of heart disease. It usually results in chest pain. That pain sends the patient to the doctor for tests. (Read about "Cardiovascular Tests") If those tests do not show any blockages in the main arteries to the heart, CMD may be the cause. CMD is the result of narrowing of the tiny arteries that supply blood and oxygen to the heart muscle. It is generally found in women. A smaller percentage of men also have the condition.

When you think of heart disease, you probably imagine an artery clogged with a chunk of plaque. (Read about "Arteriosclerosis & Atherosclerosis") That's usually how cholesterol (Read about "Cholesterol") accumulates in the arteries of men and women. In CMD, plaque accumulates in the very small arteries of the heart, causing narrowing and reduced blood and oxygen flow. This often results in chest pain. (Read about "Angina") The Cardiovascular Research Foundation (CRF) says that in the past, the term Syndrome X has been used for the condition.

CMD is a relatively new concept. It's different from traditional coronary artery disease. (Read about "Coronary Heart Disease") In 1996, a study found that in women, an inadequate flow of blood to the heart could escape detection by angiography, a traditional tool used for diagnosing blockages. This is because the plaque forms in the very small arteries of the heart and causes narrowing, not large blockages. The study, called WISE (Women's Ischemia Syndrome Evaluation) laid the groundwork for new diagnostic tools and treatments for women with heart disease. (Read about "Heart Disease & Women")

Symptoms

CMD sometimes takes on the typical symptoms of large heart blockages such as a crushing chest pain, sweating and shortness of breath. (Read about "Sweating") But symptoms can also be vague, and may include:

• fatigue
• upset stomach
• pain in the jaw or shoulders
• flu-like symptoms
• anxiety (Read about "Anxiety")

The National Heart, Lung and Blood Institute (NHLBI) says that because of these uncertain symptoms, diagnosing CMD can be challenging for doctors. This is especially true if common screening tools for heart disease reveal nothing unusual.

Diagnosis and treatment

Women with CMD have plaque buildup in the smallest heart arteries causing a slow reduction in oxygen flow. This makes it particularly difficult for doctors to diagnose this type of heart disease. Standard chest X-rays, CT scans (Read about "X-rays" "CT Scan - Computerized Tomography") and angiographies usually miss the problem. NHLBI says a questionnaire called the Duke Activity Status Index (DASI) is often used to understand how well the patient is able to do everyday activities. CMD usually manifests itself first when people start having problems doing routine daily tasks. NHLBI also lists other steps for diagnosing CMD. These include:

• Stress Test - may be ordered to see if the heart is getting enough blood during exercise. (Read about "Stress Test")
• Angiogram - may be ordered to determine if the arteries of the heart are blocked. (Read about "Cardiovascular Tests")
• Electrocardiogram (EKG) - could be done to assess blood through the arteries and heart. (Read about "EKG - Electrocardiogram")

A diagnosis of CMD may be given if there are no blockages and further tests rule out problems like:

• heart valve disease (Read about "The Heart & Its Valves")
• muscle problems
• throat problems
• vascular dysfunction (Read about "Vascular System")
• coronary artery spasm

According to the NHLBI, once CMD is detected, it may be treated with drugs. These may include:

• ACE (angiotensin converting enzyme) inhibitors to help keep blood vessels open
• nitrates such as nitroglycerin to relax blood vessels and help with chest pain
• blood pressure drugs including calcium channel blockers and beta blockers (Read about "Hypertension: High Blood Pressure")
• statins to help lower cholesterol (Read about "Cholesterol")
• aspirin and anticoagulants to thin the blood and keep clots from forming (Read about "Aspirin & Heart")

Causes and prevention

NHLBI reports the causes of CMD are still largely unknown and can vary from patient to patient. But the agency recommends adopting a heart-healthy lifestyle, which includes:

• no smoking (Read about "Quit Smoking")
• exercising (Read about "Getting Started on Fitness" "Walking for Health")
• following a heart-healthy diet (Read about "Dietary Guidelines" "Low-Fat Food Tips")
• keeping cholesterol and blood pressure at healthy levels

CRF says there is some suggestion that hormones may play a role in the development of the condition. That would help explain the reason that many more women have CMD than men.

According to the NHLBI, studies suggest that people with CMD have no higher risk (Read about "Heart Risks") of suffering a heart attack (Read about "Heart Attack") or dying from cardiovascular conditions than other heart patients. (Read about "The Heart & Cardiovascular System")