AUSTIN, Texas (WOMENSENEWS)--Two recent studies indicate that women, particularly younger women, are more likely than men to die following angioplasty and coronary artery bypass surgery, two common procedures performed after a heart attack. Doctors admit they do not yet understand why.
Bypass surgery replaces or bypasses an obstructed coronary artery with a section of healthy artery, often taken from the leg. In angioplasty, a catheter tipped with a deflated balloon is inserted in the artery and inflated at the obstruction to widen the artery and increase blood flow.
Women under age 50 were three times more likely to die in-hospital after coronary artery bypass surgery than were men, adjusted for other risk factors, according to an Emory University study led by Dr. Viola Vaccarino and published in Circulation: Journal of the American Heart Association on March 12.
Vaccarino says many factors could be at work: women come in for treatment later; women's smaller arteries may make the procedures more difficult and women's artery disease may be more diffuse, spread beyond the heart's arteries into the body's tiniest vessels. If cardiovascular disease is more diffuse in women than in men, bypass surgery, which repairs the heart's major arteries, would not be reaching and clearing it.
Another study published recently in Circulation found that women have more than twice the risk of death than men after a first heart attack is treated with angioplasty, regardless of age.
Women are at a greater risk of dying because they arrive at the emergency room later than the men, not recognizing the heart attack symptoms as quickly, said Dr. David L. Brown of Montefiore Medical Center's Albert Einstein College of Medicine in New York, an author of the angioplasty study. Many women have unusual symptoms such as peculiar back or elbow pain instead of the classic chest pressure, although women also experience more familiar heart attack signs such as chest pain, shortness of breath and nausea, Brown said.
In addition, women are more likely to go into shock than men when experiencing a heart attack. Shock is a life-threatening drop in blood pressure, a circulatory failure that can happen when the heart doesn't pump or pumps erratically, as in a heart attack.
"Women don't appear to tolerate the insult of their heart muscle dying the same as men," says Brown. "Even if, hypothetically, a man and a woman have a heart attack of the same size, the women seem to tolerate it less well than the men and nobody knows why."
Until Recently, Heart Disease Considered a Man's Disease
Traditionally, heart disease has been considered a man's disease and women were presumed to be protected by estrogen, according to Vaccarino. Clinical trials have systematically excluded women and research on women's heart disease only really began after the National Institutes of Health issued guidelines in 1993 requiring that women and minorities be included in research trials.
Education also lags, according to Brown. Women seem more aware of cancer risks than heart disease signs and many primary care doctors practice according to older medical school training that maintains it's uncommon for women to have heart attacks.
Meanwhile, Brown says, "The heart attack rate is going up in women and going down in men."
Women should ask for a stress test, since their doctors are less likely to suggest one, advises Brown. "There's a misperception among doctors that stress tests are inaccurate in women and not worth doing," he says, a belief that arises from statistical misunderstanding and not the test's effectiveness in women.
In the treadmill stress test, a patient's heart is monitored while she walks on a treadmill. The exercise is the "stress" that tests the heart and circulation, revealing obstructed arteries.
Brown urges women to ask their doctors about the heart disease risk factors such as hypertension, family history, diabetes, overweight and cholesterol. And he says they should stop smoking.
"The data I've seen," says Brown, "are that young girls are the only segment of the population where incidence of smoking is increasing."
However, the available tests may not be enough though, cautions Vaccarino. There's a paradox, she says: Among those undergoing bypass surgery, women with severe symptoms show less disease on their coronary angiogram than men with fewer symptoms. A coronary angiogram produces an X-ray image of the heart and its arteries heightened by contrast dye.
This may be because heart disease is more diffuse in women, which makes it more difficult to see in the angiogram.
"We have to find new ways to find the disease in women and new ways to treat it," says Vaccarino.
Dr. Rose Marie Robertson of Vanderbilt University Women's Heart Institute in Nashville, Tenn., says she is baffled by the greater mortality found in the studies but still believes bypass surgery and angioplasty benefit women. The findings "may reflect the reactivity of their blood vessels, it may reflect different degrees of inflammation, but I don't think we have the answer yet."
"Do I think there's enough research? Of course I don't," Robertson says. "Cardiovascular disease will kill more than half the women in this country. The dollars that have been directed to cardiovascular research are not congruent with the risk to the population."
Suzanne Batchelor has written also for WebMD, MedscapeHealth.com, "Healthline Texas" and the national science series "Earth and Sky."
For more information:
WomenHeart, the National Coalition for Women with Heart Disease:
Society for Women's Health Research
American Heart Association