Heart disease doesn't discriminate. It is the leading killer of men and women. But when it comes to diagnosing and treating it, there is a gender gap. Women with heart attacks are more likely to die than men...and that's not just older women. Women of all ages are more likely to die. According to one Israeli study that adjusted for age, size and other factors, the death risk for women was 1.7 times that of men.
During the past decade, heart attack survival has improved greatly thanks to thrombolytics (clot-buster medication) like TPA and streptokinase. But how often do women get these drugs? In one Washington state study, of 1,078 subjects screened for TPA eligibility, 39 percent of the women were too old, 59 percent had nondiagnostic electrocardiograms and 30 percent came to the hospitals too late. Overall, only 16 percent of the women screened were eligible for TPA, compared with 25 percent of men. Of those eligible women, 55 percent received the drug, compared with 78 percent of the men.
It was not clear as to whether the difference was due to patient or physician refusal, failure of emergency room staff to offer thrombolytic therapy or to other causes. One way women can get the benefit of clot busting drugs is to get to the hospital quicker. Studies have shown that women with chest pain wait too long before heading to the emergency room. (Thrombolytics are 50 percent effective if given within the first hour of having a heart attack but drop to only 20 percent effectiveness if given 2-6 hours later). But does clot busting work better in men than in women? Large Studies have found that women's survival improves with these drugs, but not to the same extent as men, though it is not known why.
Treadmills as a screening tool for diagnosing heart disease are accurate in men but not so in women. In one study comparing the accuracy of treadmill tests in women and men, misleading treadmill results occurred in 35 percent of the women studied. When combined with nuclear imaging using thallium (a low-dose radioisotope), the accuracy rate improved in women, provided the interpreter was trained to take breast tissue and valve plane artifacts into account.
Abnormal treadmill tests have been related to phases of the menstrual cycle and to oral contraceptive use, implicating sex hormones as a factor. It may be estrogen's effect on cardiocytes - the cells of the heart muscle. Another explanation for the variations in test results may be the effect of catecholamines (stress hormones i.e. adrenaline) on the vasomotor tone and the higher prevalence of mitral valve prolapse among women.
Stress tests induced by drugs (dipyridamole, adenosine or dobutamine) rather than with exercise may actually be preferable in women since many elderly women cannot endure the physical demands of treadmill testing and sub-optimal heart rates are achieved. Again, the use of thallium improves the accuracy of this stress test as well.
Either stress test when combined with echocardiography is more accurate for diagnosing heart disease in women with comparable results to nuclear imaging. With a skillful, experienced technician, the graphic images of the functioning heart muscle can be accurately interpreted. By using sound waves, echocardiography has the added advantage of avoiding breast artifacts (inaccurate readings due to breast tissue).
Angiography is a dye study using the cardiac catheterization procedure with x-rays to view blocked vessels. It remains the gold standard for diagnosing coronary artery disease, but, unlike nuclear imaging, it has its risks. Women with heart attacks or unstable or stable angina are less likely to be referred for angiography than are men with the same diagnoses. It is debatable whether this reflects under use of angiography in women or overuse in men.
When it comes to balloon angioplasty, women should do as well as men but they don't. More women die after angioplasty and their complication rates are higher then for men (The age adjusted death rate for women is 4 times that of men, according to the American Heart Association).
Though women undergoing angioplasty are generally older than the men - and more likely to have other conditions like diabetes and high blood pressure - gender remained an independent predictor of risk, according to a study by the National Heart, Lung and Blood Institute. The track record on bypass surgery isn't any more encouraging. More women die from bypass than men...and that's not because they are older at the time of surgery.
In one study of 6,630 subjects, the death rate for women was significantly higher in all age groups. Four women undergoing bypass surgery died for every man in the 40 to 49 year group. In the 50 to 59 group, it was three women for every man. One possible explanation is women's smaller size. In a study done at the Cleveland Clinic, the death rates for women and men were nearly three to one.
When matched for age, severity of chest pains and extent of disease, the risk was two to one. But once body size was factored, gender was no longer a predictor. Another explanation could be their poorer health status at the time of the surgery. One study found that women were more seriously ill compared with men at the time of surgery. This could mean that women are referred at a later stage of their disease, subjecting them to more risk. But one study from Duke University concluded that, although women with heart disease were less likely in general to be referred for bypass, among patients with higher likelihood of cardiac death, women and men were referred with equal frequency.
In conclusion, coronary artery disease is the leading cause of death in women. More than twice as many women die from cardiovascular disease as from all forms of cancer combined. Evaluation for suspected coronary disease differs in women because of frequently misleading results provided by treadmill testing without imaging. Gender differences have been observed in treatment practices, but since more is not necessarily better in this setting, the optimal approach for women has yet to be established. Opportunities remain for the physician to work in partnership with the patient for early intervention in women with symptoms of coronary artery disease, including responding to chest pain.
This article was contributed by Judith Hsia, M.D, physician scientist at the George Washington University, Department of Medicine in Washington, D.C.
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©1999-2000; updates: 2002, 2004, 2005, 2007 Women's Heart Foundation, Inc. All rights reserved.
Unauthorized use prohibited. The information contained in this Women's
Heart Foundation (WHF) Web site is not a substitute for medical advice or
treatment, and WHF recommends consultation with your doctor or health care
©1999-2000; updates: 2002, 2004, 2005, 2007 Women's Heart Foundation, Inc. All rights reserved. Unauthorized use prohibited. The information contained in this Women's Heart Foundation (WHF) Web site is not a substitute for medical advice or treatment, and WHF recommends consultation with your doctor or health care professional.