|
 In
the spring of her 58th year, Anita Chudnow of Milwaukee, Wis.,
was working in her garden when a sudden and extreme fatigue
overcame her. She went in to lie down and didn't have the
energy to get up to make dinner several hours later. Convinced
that something was amiss, her family insisted she see a doctor.
He put her through a battery of tests, which revealed that
three of Chudnow's heart arteries, called coronaries, were
choked with a fat-like deposit called plaque
The plaque
had narrowed her arteries, depriving her heart of the oxygen-rich
blood it needed to function. "I couldn't believe it,"
said Chudnow, recalling her surprise at learning she had coronary
heart disease, although she was familiar with the condition
because her father had it. "Maybe I thought heart disease
was a man's disease because of all those years my father suffered
from it. I went with him in the ambulance to the hospital
so many times and I never thought the same thing could happen
to me," she said. Unfortunately, Chudnow isn't the only
one with that misconception. Although heart disease has been
the number one killer of women since shortly after the turn
of the century when it overtook infectious diseases, most
people aren't aware of how common--and how deadly--the disorder
is in women.
"This
is a problem," said cardiologist Nanette Wenger, M.D.,
of Emory University in Atlanta, "because unless women
see heart disease as part of their disease profile, they're
not going to adhere to heart disease prevention messages early
in life and they're not going to respond to heart disease
symptoms later on." The lack of awareness of heart disease
in women was fueled, in part, by the early findings of the
landmark Framingham Heart Study. In this study, which began
in 1948 and is still ongoing, researchers have scrutinized
the habits and health of thousands of middle-aged men and
women from Framingham, Mass. After collecting data for a little
over a decade, they found that three times more men died from
heart disease during this period than women, which led to
the conclusion that women were somewhat protected from the
condition.
Further
analyses of the Framingham data and a study conducted at the
Cleveland Clinic revealed, however, that women aren't spared
from medical matters of the heart, but rather tend to develop
them about 10 to 15 years later in life than men. According
to the American Heart Association, 1 in 9 women aged 45 to
64 has some form of heart or blood vessel disease; this ratio
soars to 1 in 3 at age 65 and beyond. The approximately 500,000
heart attack deaths that occur annually in this country, in
addition, are evenly split between men and women. Each year,
nearly twice as many women die from heart disease and stroke
than from all forms of cancer combined. Despite the prevalence
and seriousness of heart disease among women, much of what
is known and popularized about it is based on research done
in men. The studies that have included women suggest, however,
that many of the mainstays of diagnosis, treatment and prevention
of coronary heart disease may not apply to the female gender.
As with
other drugs and populations, FDA is responsible for the safety
and effectiveness in women of medications for heart disease.
Discrepancies in Diagnosis One of the telltale signs of heart
disease is chest pain or tightness, known as angina, that
occurs during physically demanding tasks such as climbing
stairs, or under emotional strain. This pain can make a person
short of breath. It can radiate to the jaw, neck, shoulders,
or inner arms. Angina occurs because narrowed arteries in
the heart deprive it of oxygen-rich blood. If a blood clot
completely chokes off the blood supply in these arteries in
what is known as a heart attack, chest pain usually becomes
more severe and lasts longer. But chest pain may not be as
good a diagnostic clue of serious heart disease in women as
it is in men. Nearly twice as many men as women with chest
pain that may be angina actually have coronary heart disease.
This finding is from the National Institute of Health's Coronary
Artery Surgery Study. It may stem, in part, from women being
more likely than men to have such conditions as heartburn
or spasms of the esophagus or heart arteries, which can cause
chest pain that resembles angina. But given the dire consequences
of heart disease that goes unrecognized, Wenger said that
any woman complaining of chest pain should be taken seriously
by her doctor. She and other experts at a 1992 conference
convened by the National Heart, Lung, and Blood Institute
recommended that doctors carefully evaluate women (and men)
with chest pain, based on their symptoms and risk factors
for heart disease, such as smoking or high blood pressure.
These
patients should then have tests to detect abnormalities prompted
by narrowed heart arteries or a previously unrecognized heart
attack. But some of these commonly performed tests are less
accurate in women then men and have prompted some cardiologists
to reject their use in female patients altogether. One standard
test is an exercise stress test, during which the patient
exercises on a treadmill while the activity of the heart is
electrically monitored. But this test falsely predicts heart
disease in as many as half the women tested, studies show.
In addition, many women cannot exercise long enough for such
a test because, at their older age, they have exercise-limiting
illnesses, such as arthritis. Researchers recently developed
statistical standards for the treadmill stress test in women
that uses a woman's age and risk factors for heart disease
to improve accuracy. Wenger is satisfied enough with these
modifications to prescribe the treadmill stress test for her
female patients, if they can exercise. But other cardiologists
still question its accuracy because they think most doctors
don't have the information they need to adequately assess
a woman's risk factors for heart disease.
"I
don't do stress treadmill tests in women," said Marianne
Legato, M.D., of Columbia University. "They're a waste
of $600." 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.
Prevention
Tactics Vary The tricks of the trade for preventing coronary
heart disease also vary from men to women. Post-menopausal
women may have the option of possibly delaying or preventing
the onset of heart disease by taking daily estrogen, in a
dose comparable to what their bodies generated before menopause.
Some studies suggest that women who take estrogen during and
after menopause have about half the risk of heart attack as
women who don't take the hormone. Natural production of estrogen
before menopause, some researchers speculate, may explain
why women develop heart disease later than men. Whether estrogen
replacement therapy may help delay or prevent heart disease
in women, however, remains unproven. Since women selected
for estrogen treatment in studies were often healthier, slimmer,
and more active than those who didn't receive the hormone
therapy, their reduced heart attack risk could have been due
to lifestyle characteristics rather than by the estrogen treatment.
Because of these uncertainties, FDA has not approved the use
of estrogen for prevention of cardiovascular disease. Use
of estrogen after menopause is linked to a greater risk of
developing endometrial cancer. To counter that risk, estrogen
is often prescribed with the hormone progestin. Whether this
hormone combination also prevents heart disease in women is
also unknown. To resolve this question and to prove whether
estrogen replacement therapy prevents heart disease in women,
the National Institutes of Health has undertaken a randomized
clinical trial as part of the Women's Health Initiative. Results
are not expected to be available for five to 10 years, however.
A mainstay in treating and preventing heart disease in men
is a diet low in cholesterol, a fat-like substance carried
in the blood and used by the body to build cell walls, sex
hormones, and a variety of other vital substances. (See "Lowering
Cholesterol" in the March 1994 FDA Consumer.) When too
much cholesterol accumulates in the blood, it clogs arteries.
The amount of the two main types of cholesterol found in the
blood, however, is key to pinpointing heart disease risk.
Cholesterol carried by low-density lipoproteins (LDLs) is
more likely to be deposited on artery walls, unlike cholesterol
carried by high-density lipoproteins (HDLs), which often is
ferried back to the liver where it is processed or removed.
High levels of HDL cholesterol and low levels of LDL cholesterol
are linked to lower risk of heart disease in both men and
women. But HDL levels are a much more powerful predictor of
heart disease risk in women than LDL levels, several studies
suggest. A low-cholesterol, low-saturated-fat diet can lower
blood cholesterol by more than 15 percent in men. Epidemiological
studies of men also found that each 1 percent drop in blood
cholesterol was accompanied by a 2 percent drop in the risk
of a heart attack. Research suggests high cholesterol is a
risk factor for heart disease in women, too, but experts debate
whether women should strive to lower their cholesterol to
the levels recommended by the American Heart Association because
these levels are based on studies done primarily in men.
A cholesterol-lowering
diet in women not only lowers LDL cholesterol, but nearly
equally lowers their HDL cholesterol, pointed out John Crouse,
M.D., of the Bowman Gray Medical School in North Carolina.
Because high HDL levels are so much more protective in women
than low LDL levels, lowering total cholesterol may not benefit
women and may do more harm than good, he claims. The National
Heart, Lung, and Blood Institute is conducting several studies
to assess if this is the case. Like men, however, women can
help prevent heart disease by using medications or other measures
to stem high blood pressure, losing weight if they are overweight,
and not smoking. Both sexes should adhere to a low-fat diet
and not consume alcohol if they have high blood levels of
triglycerides, a type of fat produced by the liver when alcohol
is drunk or when excess calories are taken in. Scientists
are studying whether vitamin E and the vitamin A precursor
beta carotene may also help stave off heart disease.
Women
with a high vitamin E consumption had a 34 percent lower risk
of heart disease, according to an epidemiological study by
Meir Stampfer, M.D., of Brigham and Women's Hospital in Boston.
In the same study of more than 87,000 nurses, those with boosted
beta carotene consumption had a 22 percent lower risk of heart
disease. Vigorous aerobic exercise is often touted as a heart
disease preventive. But regular walking may be equally effective,
according to a small epidemiological study at the Cooper Institute
for Aerobics Research in Dallas. Women who walked three miles
a day, five days a week decreased their risk of heart disease,
even if they took 20 minutes to walk a mile. Much more research
needs to be done, however, to paint a complete and accurate
picture of the best ways to prevent, diagnose and treat heart
disease in women. "It's only been about five years,"
noted Wenger, "that we've begun to carefully look at
heart disease in women, in contrast to 30 years experience
looking at it in men--we have a lot of catching up to do."
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