Women and Heart Disease : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 3)

Legato prefers women to exercise while the heart's activity is monitored by ultrasound in what is known as a stress echocardiogram. Experts agree that this test is accurate in both men and women, as is the thallium exercise stress test, in which blood flow to the heart is imaged during exercise with radioactive tracers injected into a vein. Adjustments must be made for a woman's breast tissue, however, which can obscure the radioactive signals emitted from heart arteries.

Another test, called nuclear ventriculography, uses radioactive tracers to measure how much blood is pumped by the heart with each beat at rest and during exercise. The test is not accurate in women, however, and, according to the American Heart Association, is not recommended as a screening tool for women until standards applicable to them are developed.

None of these tests can effectively and practically screen on a routine basis symptom-free men or women for heart disease. This is unfortunate because women are more likely than men to have "silent" or unrecognized heart attacks.

Part of the reason more women have undetected heart attacks, according to Legato, is because women often have signs of a heart attack that differ from those typical in men. Women are more likely than men to have nausea and pain high up in the abdomen or burning in their chest during a heart attack. "Women ought to be careful of what they're calling 'indigestion'," Legato said.

Other women, such as Chudnow, have atypical angina that includes extreme fatigue on physical exertion rather than chest pain.

Deadly Difference

Whether silent or replete with telltale symptoms, heart attacks or their aftermath tend to be more deadly in women. About one-quarter more women than men die within a year of having a heart attack. This difference may stem from women generally being older than men when they suffer heart attacks. (Their older age makes them more likely to have other illnesses that hamper survival.) Also, women do not respond as well as men to treatments for heart disease usually prescribed during or after a heart attack.

These treatments include coronary angioplasty. In this procedure, a tiny balloon is inserted into blocked heart arteries and their branches, and then inflated to compress the plaque that is obstructing the flow of blood to the heart. A recent study by Sheryl Kelsey, Ph.D., of the University of Pittsburgh found that women were 10 times as likely as men not to survive coronary angioplasty. When women and men of the same age and with the same history of heart disease were compared, women's risk of death during the procedure was still nearly five times higher than men's.

Other studies show that women are twice as likely as men to have heart disease symptoms four years after angioplasty, according to Wenger. She speculates the effectiveness of angioplasty in women might be limited by their smaller blood vessel size. Angioplasty cannot be performed on blood vessels that are too small, so doctors may not be able to treat all the blockages in women's heart arteries with the procedure, Wenger said.

An alternative therapy to angioplasty is coronary bypass surgery, in which portions of leg veins or an artery in the chest are removed and attached to the heart to provide alternate routes for blood flow, bypassing blocked arteries. Women are two to three times less likely than men to survive this procedure, according to Wenger, perhaps because women are generally older and sicker than men when they have the surgery. If women do survive the operation, however, their five-year survival rate following heart bypass surgery is the same as for men.

A treatment for heart attacks that appears to be equally effective in men and women is "clot-busting" drugs and biologics such as tissue plasminogen activator and streptokinase, both approved by FDA for this purpose. When one of these is given within hours of a heart attack, it can limit the damage to the heart by quickly dissolving the clots blocking heart arteries. But women are more likely than men to suffer internal bleeding complications, including a hemorrhagic stroke, from these products. Wenger speculates the standard doses, set from testing done mainly in men, are not appropriate for women.

Aspirin and beta-blocker drugs are equally effective in women and men in preventing a second heart attack. But when it comes to other commonly used heart medications, such as those used to dilate blood vessels, "virtually none of these drugs have been studied in women," said Wenger.

The usually smaller body size and higher body-fat content of women, and the hormones generated or taken by women may alter the effects of drugs, according to Ruth Merkatz, Ph.D., R.N., of FDA.

Recognizing the problems with prescribing drugs for women that have been analyzed mainly in men, FDA recently issued a guideline that requests women be adequately represented in new drug tests and that the drugs' safety and effectiveness be analyzed for both genders. FDA also recently set up an Office of Women's Health, to focus on women in clinical trials and develop other measures needed to ensure that most drugs are tested and analyzed in both men and women, said Merkatz, who heads the office. "We won't close the loop and have all the answers tomorrow," she added, "but over the next few years we'll have much more information on cardiovascular treatments for women."

FDA is also working with academic institutions to further test in women some commonly used cardiovascular drugs already on the market, such as propranolol and quinidine, two heart drugs.

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