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When it comes to heart disease, not only are the symptoms sometimes different for men and women – but the disease itself may be different.
There's an entertaining theory that men and women are from different planets. It's a not-so entertaining fact that men and women experience heart disease differently. It's not always clear why, but women are less likely to survive a heart attack than men. Women have a 50 percent greater chance of dying during heart surgery. And, they're more likely than their male counterparts to develop heart failure, a weakening of the heart muscle that can be incapacitating and ultimately fatal.
Heart disease kills 500,000 women every year – ten times more than breast cancer and more than all other cancers combined. It's also a leading cause of disability. Eight million women are currently living with it. While women develop cardiovascular disease about ten years later than men, it's estimated that one in ten American women 45 to 64 years of age has some form of heart disease, increasing to one in four women over the age of 65.
Historically, studies that set the standard for detection and treatment of heart disease were mostly done on men. But researchers found the results didn't always apply to women. Now, thanks to new research sponsored by National Institutes of Health (NIH) National Heart, Lung, and Blood Institute (NHLBI), more attention is being directed toward a better understanding of the unique features of heart disease in women.
Here's what scientists are finding out about gender differences and heart disease.
· Women with heart disease may have different symptoms than men. Women may experience the classic symptoms of gripping chest pain, sweating and shortness of breath, but they also may present with vaguer symptoms like generalized discomfort in the chest, breast, back, shoulders, jaw, neck or throat; indigestion; nausea; light-headedness; palpitations; sleep disturbances; and unexplained fatigue.
· Tests that reliably pick up signs of heart damage in men don't always work in women. These range from simple blood tests to exercise stress tests to standard angiograms. Some women don't have the strength to do a full exercise stress test and an incomplete one doesn't work the heart enough to yield truly useful results. Single-vessel heart disease, which is more common in women than in men, may not be picked up on a routine exercise stress test. Women with chest pain and other heart symptoms are more likely than men to have coronary microvascular disease even though tests show clear large coronary arteries. (See More About Women and Coronary MVD below.)
· Women tend to have heart attacks later in life. As a result, they're more likely to have other health issues. Symptoms of heart disease might be attributed to existing conditions such as arthritis or diabetes. Problems like high blood pressure, high cholesterol and diabetes may make surgery a riskier proposition for them.
· Women have smaller hearts and arteries than men. One reason women haven't fared as well as men after bypass surgery and balloon procedures may be that their smaller vessels clog up again more easily after the procedures. In addition, surgeons performing bypasses in women are less likely to use an artery from inside the chest wall, because it's smaller and harder to work with, even though using the chest artery gives most patients better odds of long-term survival.
· There may be fundamental differences in the way women's hearts work. Researchers believe that women have a different intrinsic rhythm to the pacemaker of their hearts, causing them to beat faster. They also hypothesize that it may take a woman's heart longer to relax after each beat.
More About Women and Coronary MVD
Several recent landmark studies have revealed that more women than men suffer from coronary microvascular disease. It's estimated that of the 8 million women in the U.S. with heart disease, as many as 3 million of them have coronary MVD.
The diagnosis of coronary MVD poses a unique challenge. Chest pain and other symptoms that the heart muscle isn't getting enough blood have traditionally signaled a narrowing or blockage in one or more of the heart's large arteries – a condition that's easily seen on an angiogram. But, in about 50% to 60% of symptomatic women and 20% of men, the problem lies not in the major arteries but in the smaller branches which are virtually invisible on a standard coronary angiogram. Bottom line, coronary MVD, like traditional coronary artery disease (CAD), increases a woman's chance for a heart attack.
Researchers are just beginning to understand coronary MVD. The same risk factors that cause problems with the larger coronary arteries – heredity, age, race, blood pressure, blood cholesterol, obesity and smoking – may also contribute to coronary microvascular disease. Women appear to be more affected by certain factors, such as high blood pressure, smoking and diabetes than men. In addition, there are a host of other risk factors unique to women. Only women become pregnant, experience menopause and are prescribed contraceptive pills and postmenopausal estrogens.
Theories on why the disease may differ in women include the following:
• Low levels of estrogen. Because estrogen plays a role in processing nitric oxide, which helps arteries function properly, the endothelium may suffer when natural estrogen levels wane.
• More inflammation (an overreaction by the immune system). Inflammation stimulates the body to use cholesterol in the bloodstream as a band-aid to cover up irritated areas in the blood vessels.
• Higher incidence of anemia. Anemia is thought to slow the growth of cells needed to repair damaged blood vessels.
• Lower levels of hemoglobin (a protein in red blood cells that carries oxygen). Hemoglobin deficits may starve the heart muscle and also reduce nitric oxide levels.
• Lower HDL ("good" cholesterol) levels. There is evidence that having low HDL is more predictive of the development of coronary heart disease in women than high LDL ("bad" cholesterol) levels are.
Findings so far have raised as many questions as have been answered, but the work represents a good start in zeroing in on ways to tailor diagnosis specifically for women. Progress has already been made in educating doctors about symptoms that, in the past, were under-recognized or misinterpreted in women. Scientists are now focusing on how diagnostic and treatment techniques may need to be changed to improve women's outcomes.
Learn more about Coronary Microvascular Disease:
Key Point 2: Coronary microvascular disease is tough to diagnose. If you are experiencing symptoms that concern you, don't ignore them. You need to continue a dialog with your doctor until you're both satisfied.
Key Point 3: If you've been diagnosed with coronary microvascular disease, getting adequate blood flow to your heart is critical. Lifestyle changes are the most effective treatment.
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