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. 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. That's usually how 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.  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.  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.

Symptoms 

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

• fatigue 
• upset stomach 
• pain  in the jaw or shoulders 
• flu-like symptoms 
• 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 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. 
• Angiogram - may be ordered to determine if the arteries  of the heart are blocked. 
• Electrocardiogram (EKG) - could be  done to assess blood through the arteries and heart. 
• A diagnosis of CMD may be given if there are no blockages and further  tests rule out problems like: 
• heart valve disease
• muscle problems 
• throat problems 
• vascular dysfunction 
• 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 
• statins to help lower cholesterol 
• aspirin and anticoagulants to thin  the blood and keep clots from forming 

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 
• exercising
• following  a heart-healthy diet 
• 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  of suffering a  heart attack or dying from cardiovascular conditions than other heart patients.