(LifeWire) - Microvascular angina feels much like its better-known cousin, angina pectoris. Both can produce chest pain or discomfort, a crushing or burning sensation in the chest, and pain or numbness in the arms, shoulders or jaw. They have different causes, though. Angina pectoris results from insufficient blood flow to the heart through the coronary arteries. Microvascular angina results from inadequate blood flow through the tiny cardiac blood vessels.
Since microvascular angina isn't characterized by significant arterial blockages, it's harder to recognize and diagnose. Yet this problem is quite common. For example, about 20% to 30% of angiogram imaging scans for patients experiencing chest pain show relatively normal coronary arteries.
According to the American Heart Association, about 9.1 million Americans experience angina, but that figure does not distinguish between angina pectoris and microvascular angina, sometimes referred to as Cardiac Syndrome X.
Scientists once believed there was no link between microvascular angina and increased risk for cardiac events, such as heart attack. But newer studies have challenged that view, although the overall risk doesn't appear to be extreme. For example, a 2008 report in the American Heart Journal found that 1% of microvascular angina patients died within a year of first being hospitalized for the condition and 0.6% suffered a stroke.
Angina is most prevalent among men older than age 30, but there is a sharp disparity with gender. Women are far more disposed to microvascular angina, and about 70% of those diagnosed are women nearing or past menopause. Researchers think this gender disparity could have several sources, including the postmenopausal drop in estrogen levels.
Microvascular angina has many possible causes. The small vessels near the heart may have blockages that doctors can't detect with imaging scans. The vessels may experience spasms during times of exertion, which is one reason why the condition typically improves with rest, or the lining of the blood vessels (the endothelium), which typically releases chemicals to help the vessels dilate and contract, may not be functioning properly.
Treatment for microvascular angina, which is similar to the treatment for angina pectoris, require lifestyle changes, such as controlling high blood pressure, diabetes, weight and smoking. Certain medications help prevent or alleviate symptoms, including nitroglycerin, which improves blood flow to the heart, and calcium channel blockers or beta blockers, which lower the oxygen needs of the heart or reduce its workload.
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"Cardiac Syndrome X." hearthealthywomen.org. 2008. Cardiovascular Research Foundation. 10 Nov. 2008. <http://www.hearthealthywomen.org/index.php?option=com_content&view=article&id=73:cardiac-syndrome-x&catid=37:Cardiac%20Syndrome%20X&Itemid=44>.
"Heart Attack and Angina Statistics." americanheart.org. 2008. American Heart Association. 10 Nov. 2008. <http://www.americanheart.org/presenter.jhtml?identifier=4591>.
Humphries, Karin H., Aihua Pu, Min Gao, Ronald G. Carere, and Louise Pilote. "Angina With 'Normal' Corornary Arteries: Sex Differences in Outcomes." American Heart Journal 155:2(2008) 375-381. 10 Nov. 2008. <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9H-4RCW7WX-7&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=80ffd57f1fdbb85d8c20e0c226dfbe86>. (subscription)