DOCTOR'S VIEW ARCHIVEMedical Author: Carolyn J. Crandall, MD, FACP
Medical Editors: Dennis Lee, M.D., Jay W. Marks, M.D., Daniel Lee Kulick, M.D.
What is the Risk of heart attacks in women?
Coronary artery disease (CAD) and heart attacks are erroneously believed to occur primarily in men. Although it is true that the prevalence of CAD among women is lower before menopause, the risk of CAD rises in women after menopause. At age 75, a woman's risk for CAD is equal to that of a man's. CAD is the leading cause of death and disability in women after menopause. In fact, a 50-year-old woman faces a 46% risk of developing CAD and a 31% risk of dying from coronary artery disease. In contrast, her probability of contracting and dying from breast cancer is 10% and 3%, respectively.
The risk factors for developing CAD in women are the same as in men; they are increased blood cholesterol, high blood pressure, smoking cigarettes, diabetes mellitus, and a family history of coronary heart disease at a young age.
Even "light" smoking raises the risk of CAD. In one study, middle-aged women who smoked 1 to 14 cigarettes per day had a twofold increase in strokes (caused by atherosclerosis of the arteries to the brain) whereas those who smoked more than 25 cigarettes per day had a risk of stroke 3.7 fold higher than that of nonsmoking women. Furthermore, the combination of smoking and the use of birth control pills increase the risk of heart attacks even further, especially in women over 35.
Quitting smoking immediately begins to reduce the risk of heart attacks. The risk gradually decreases back down to the same risk of nonsmoking women after several years of not smoking.
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Cholesterol treatment guidelines in women
Current NCEP (National Cholesterol Education Program) treatment guidelines for undesirable cholesterol levels are the same for women as for men. For more information about the NCEP guidelines, please read The Guidelines on Cholesterol for Adults article.
Diagnosis of heart attacks in women
Women are more likely to encounter delays in establishing the diagnosis of heart attack than men. This is in part because women tend to seek medical care later than men, and in part because diagnosing heart attacks in women can sometimes be more difficult than diagnosing heart attacks in men. The reasons are:
- Women are more likely than men to have atypical heart attack symptoms such as neck and shoulder pain, abdominal pain, nausea, vomiting, fatigue, and shortness of breath.
- Silent heart attacks (heart attacks with little or no symptoms) are more common among women than among men.
- Women have a higher occurrence than men of chest pain that is not caused by heart disease, for example chest pain from spasm of the esophagus.
- Women are less likely than men to have the typical findings on the ECG that are necessary to diagnose a heart attack quickly.
- Women are more likely than men to have angina (chest pain due to lack of blood supply to the heart muscle) that is caused by spasm of the coronary arteries or caused by disease of the smallest blood vessels (microvasculature disease). Cardiac catheterization with coronary angiograms (x-ray studies of the coronary arteries that are considered most reliable tests for CAD) will reveal normal coronary arteries and therefore cannot be used to diagnose either of these two conditions.
- Women are more likely to have misleading, or "false positive" noninvasive tests for CAD then men.
Because of the atypical nature of symptoms and the
occasional difficulties in diagnosing heart attacks in women, women are less
likely to receive aggressive thrombolytic therapy or coronary angioplasty, and are more likely to receive it
later than men. Women also are less likely to be admitted to a coronary care
For more, please read the Heart Attack Symptoms - Different In Women! article.
Treatment of heart attacks in women
Thrombolytic (fibrinolytic or clot dissolving) therapy has been shown to reduce death from heart attacks similarly in men and women; however, the complication of strokes from the thrombolytic therapy may be slightly higher in women than in men.
Emergency percutaneous transluminal coronary angioplasty (PTCA) or coronary stenting for acute heart attack is as effective in women as in men; however women may have a slightly higher rate of procedure-related complications in their blood vessels (such as bleeding or clotting at the point of insertion of the PTCA catheter in the groin) and death. This higher rate of complications has been attributed to women's older age, smaller artery size, and greater severity of angina. The long-term outcome of angioplasty or stenting however, is similar in men and women, and should not be withheld due to gender.
The immediate mortality from coronary artery bypass graft surgery (CABG) in women is higher than that for men. The higher immediate mortality rate has been attributed to women's older age, smaller artery size, and greater severity of angina (the same as for PTCA). Long term survival, rate of recurrent heart attack and/or need for reoperation, however, are similar in men and women after CABG.
Estrogen and coronary heart disease in women
After menopause, the production of estrogen by the ovaries gradually diminishes over several years. Along with this reduction, there is an increase in LDL ("bad" cholesterol) and a small decrease in HDL ("good" cholesterol). These changes in lipid levels are believed to be one of the reasons for the increased risks of developing CAD after menopause. Women who have had their ovaries surgically removed (oophorectomy) or experience an early menopause also have an accelerated risk of CAD.
Since treatment with estrogen hormone results in higher HDL and lower LDL cholesterol levels, doctors thought for many years that estrogen would protect women against CAD (as well protect against dementia and stroke). Many studies have found that postmenopausal women who take estrogen have lower CAD rates than women who do not. Unfortunately many of the studies were observational studies (studies in which women are followed over time but decide on their own whether or not they wish to take estrogen). Observational studies have serious shortcomings because they are subject to selection bias; for example, women who choose to take estrogen hormones may be healthier and have a lower risk of heart attacks than those who do not. In other words, something else in the daily habits of women who take estrogen (such as exercise or healthier diet) may make them less likely to develop heart attacks. Therefore, only a randomized trial (a study in which women agree to be assigned to estrogen or a placebo or sugar pill at random but are not told which pills they took until the end of the study) can establish the whether hormone therapy after menopause can prevent CAD.
HERS trial results
The Heart and Estrogen/progestin Replacement Study (HERS), was a randomized placebo-controlled trial of the effect of the daily use of estrogens plus medroxyprogesterone (progestin) on the rate of heart attacks in postmenopausal women who already had CAD. The HERS trial did not find a reduction in heart attacks in women who took hormone therapy. This lack of benefit in preventing heart attacks occurred despite an 11% lower LDL and a 10% higher HDL cholesterol level in the women treated with hormones. The study also found that more women in the hormone-treated group experienced blood clots in the veins and gallbladder disease than women in the placebo-treated group. (Blood clots in the veins are dangerous because these clots can travel to the lungs and cause pulmonary embolism, a condition with chest pain, shortness of breath, and even shock and death.) However, the increase in gallbladder disease and blood clots among healthy users of estrogen who do not have heart disease is very small.
Based on the results of this study, researchers concluded that estrogen is not effective in preventing coronary artery disease and heart attacks in postmenopausal women who already have CAD. It should be noted, however, that the results of the HERS trial only apply to women who have known CAD prior to starting hormone therapy and not to women without known coronary artery disease.
WHI trial results
The Women's Health Initiative (WHI) was the first randomized controlled trial designed to determine the long-term benefits and risks of treatment with estrogens plus medroxyprogesterone (progestin) in healthy menopausal women (women without CAD). The results were reported in a series of articles in 2002, 2003, and 2004. The estrogen + progestin portion of the WHI study had to be stopped earlier than planned, after just 5.2 years, because the increase in coronary heart disease, stroke, and pulmonary embolism among women who use estrogen + progesterone outweighed the benefits of reduced bone fractures and colon cancer. The estrogen-alone portion of the WHI was stopped because women who took estrogen alone had no reduction in heart attack risk, yet there was a significant increase in stroke risk.
The increase in breast cancer became apparent after 3-5 years, but the
increase in heart disease and pulmonary emboli occurred early on, in the first
For additional information on the WHI results, please read the article, The Women's Health Initiative in Perspective: The Last Straw for Estrogen Therapy?
Recommendations for the use of estrogens plus medroxyprogesterone (progestin) in women
Medicinenet Medical Editors believe that:
- Decision regarding use of hormone therapy has to be individualized, and all women should discuss with their physicians what is best for her.
- Estrogens plus medroxyprogesterone (progestin) is still the best therapy for hot flashes. Despite the WHI study, many women remain good candidates for estrogens plus medroxyprogesterone (progestin) therapy (or estrogen alone if they have had hysterectomy). This is especially true if hormone therapy is limited to the shortest duration, optimally less than 5 years.
- Estrogens with or without medroxyprogesterone (progestin) should not be used to prevent or treat either Alzheimer's disease, heart disease, or stroke.
- While estrogens plus medroxyprogesterone (progestin) are effective in
preventing osteoporosis and related bone fractures, women concerned about
the risk of hormone therapy should discuss with their doctors, the use of
other non-hormonal alternatives to prevent and treat osteoporosis.
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