Women and heart disease

Women and heart disease – includes related information on heart attack, gender bias in research, and tests for coronary artery disease

Although heart disease has been considered mainly a “man’s disease” and heart attack rates in women lag behind those in men, after a certain age coronary artery disease affects both sexes equally. Moreover, when women do have a heart attack they are more likely than men to die of it. Curiously, however, there is no accurate model for heart disease in women. Until now most research was done in men — women have been under-represented in heart studies, under-investigated, under-diagnosed and, some say, under-treated. They are insufficiently informed about their endangered heads or how to protect them.

Heart disease is a leading killer of women

When asked to name the chief killer of women, many will say “breast cancer.” Yet, in fact cardiovascular disease is the leading cause of death among women: 41 per cent of deaths among Canadian women — 37,000 a year — occur from heart disease or stroke, seven times more than the number due to breast cancer.

One obvious difference between coronary artery disease (CAD) in men and women is the older age at which it strikes females. Heart disease usually appears in women about 10 years later than in men (although a significant proportion of heart attack deaths in women still occur before age 45). Until menopause, women’s hearts are protected by the female hormone estrogen, but around age 50-55, as their estrogen levels drop, women start to catch up to men in CAD rates. By age 65-70, heart attack rates are similar in both sexes, with one in three affected by coronary disease.

Heart attacks are often more severe in women

Studies show that about one third of those suffering a heart attack — of either sex — die before reaching hospital. But when a woman has a heart attack her prognosis (outlook) tends to be worse than a man’s, and she is more likely to die during a first attack. Also, more women than men suffer a second heart attack soon after the first and more women die within a year of their first heart attack. Women with diabetes are at special risk.

Gender differences in cardiac management

Despite the fact that after a certain age both sexes are equally prone to CAD, women with chest pain or other coronary symptoms tend to receive less urgent attention than men — they are less likely to be investigated for heart disease and are less often referred to cardiologists. Not only do women receive fewer cardiac tests than men (reducing the likelihood of early diagnosis), but they are also less readily admitted to hospital and less likely to receive heart-saving treatment. Age and symptom-matched studies reveal that women are less often admitted to the hospital’s intensive care unit (ICU) and less often receive thrombolytic (clot-dissolving) therapy or bypass surgery. Moreover, in the past when women did get revascularization — treatment to restore the heart’s bloodflow — they often benefitted less than men. This could be because their disease was more advanced by the time they were investigated and treated and also because their smaller body size and smaller arteries were considered unsuitable for certain procedures.

The offhand medical attitude towards women’s heart problems has been echoed in medical research. Most studies that explored heart disease have enrolled only men, excluding older subjects of both sexes. Even the recently publicized large cholesterol trials were done on men only.

Why are women with heart trouble differently treated?

It is hard to determine why, as many international studies demonstrate, women have been so much less likely than men to receive state-of-the-art therapy, even though they face higher risks of death from heart attacks. Experts disagree about the reasons. Some blame the medical establishment for having a gender bias; although some suggest the difference arises not because women are under-treated, but rather because men are expensively over-treated. Others argue that the bias is not sexist but ageist. Women seeking advice for heart disease tend to be older than men with similar symptoms, may have more severe CAD and perhaps additional diseases such as diabetes. By the time women finally develop serious coronary symptoms and are appropriately treated, heart disease may be well advanced so they are sicker and more likely to die.

Another reason for the negligent attitude to female heart disease may be that family physicians, cardiologists, and women themselves don’t take chest pain seriously. Women’s heart symptoms are less well documented and their angina or chest pain differs from that in men. So physicians may not recognize female heart symptoms, or may consider the complication rate of certain treatments too high to be suggested. Physicians may have acted less vigorously in treating women because bypass surgery and other cardiac treatments were considered riskier, largely on account of their smaller blood vessels which make coronary surgery or other treatments more technically exacting. Women themselves, not realizing the risks, often fail to act promptly enough and reach hospital later than men with similar symptoms — perhaps too late to be eligible for certain heart-saving procedures. In addition, women’s own attitudes may make them more reluctant than men to accept invasive treatments. (Newer technologies are improving cardiac treatment in women.

Heart symptoms differ in men and women

In men, a heart attack is often the first (perhaps final) clue to heart trouble, while more women tend to get angina as a preliminary or warning symptom. The famous Framingham studies found that two thirds of men first “present” with a heart attack and only one third have previous angina; among women about two thirds first present with angina, only one third with a heart attack. When men do complain of angina, it tends to follow a classic, more easily recognized pattern described as squeezing or “crushing pain” and heaviness on the left side of the chest, (perhaps radiating to the shoulder or left arm) — often brought on by exercise and relieved by rest.

In women, by contrast, angina is often “atypical” and does not follow any recognizable pattern. Women with angina may just complain of “a little neck-ache,” occasional “pains in the back or breast” or “tingling in the fingers” — symptoms less easily recognizable as heart pain. Women may therefore be misdiagnosed and sent home or not thoroughly enough investigated for coronary disease. “It is distressing,” notes one cardiologist, “that although a heart attack is less likely in women, if it does occur it will more likely be fatal. The trick is to detect CAD, but once diagnosed, it should be as vigilantly treated as in men.”

Harder to diagnose heart disease in women

Detecting heart disease early in women can be difficult because of their atypical angina, and because traditional heart function tests tend to be less sensitive and less accurate in women, more often giving “false” results. Physicians may therefore neglect chest pain in women as a possible sign of heart trouble. Since further testing with an angiogram — injecting dye into the arteries — is “invasive” and carries some risk of major complications (one per 700 angiograms), physicians may hesitate to suggest it unless a woman is at definite risk of CAD. Some of the newer imaging tests are improving diagnosis in women — for instance perfusion scans and stress echocardiography.

Changing medical attitudes to female chest pain

Chest pain in men is usually taken very seriously and immediately triggers physicians to think “heart” and suggest cardiac tests such as an exercise stress test, perhaps followed by an angiogram and, if necessary, prompt treatment. British and U.S. studies have shown that women with chest pain are less swiftly investigated, have fewer tests and less easy access to bypass surgery and other treatments than men. Since women often have atypical angina, and as nonspecific chest pain is fairly common in women (especially young women), physicians may not link chest pain in women with heart disease. They might first look for other causes — such as anxiety, a panic attack, a heart valve prolapse, indigestion or heartburn (stomach acid reflux). “However,” warns one cardiologist, “physicians should not ascribe chest pain to psychological origins before doing a thorough check for coronary disease.”

Health professionals now call for more heart functions tests in women and more careful follow up and investigation. Women with known CAD risk factors, for example smokers, the obese, those with diabetes or a family history of heart disease, need to be carefully followed. One University of Toronto heart surgeon notes that “modern revascularization procedures should not be denied to women, as the long-term results of treatment are excellent. Women need to know that the benefits of bypass surgery offer not only symptom-relief but possibly also a longer life.”

Fewer women follow cardiac rehabilitation programs

After a first heart attack, women are less likely than men to attend cardiac rehabilitation programs — the cornerstone of recovery for both sexes, involving exercise, conditioning and education about risk management. Women may be less inclined than men to attend cardiac rehabilitation because they are less often referred, may be less motivated, have more caregiving duties and fewer supports — and consequently may feel they need “permission” to take time off. They are also more likely to suffer continued angina, are older and more frail, and may feel guilty about their illness. Specialists are now creating programs specially designed and oriented to women’s needs.

Male-female heart risk factors roughly similar

Risk factors that predispose people to heart disease are similar in both sexes, although glucose intolerance and diabetes are greater influences in women — even at a young age. Risk factors are cumulative — the more risk factors the greater die risk — but reducing one risk factor can also reduce others. For example, quitting smoking, losing weight and eating a low-fat diet all help to lower blood pressure, also lowering blood cholesterol and helping to control diabetes.

Risk factors for heart disease in women

* Advancing age;

* Hormonal (estrogen) status — post-menopausal;

* Family history of early CAD;

* Diabetes mellitus;

* Sedentary lifestyle — lack of exercise;

* Cigarette smoking;

* Elevated blood cholesterol;

* High blood pressure (hypertension);

* Stress (and too few vacations);

* Being overweight or obese.

Analyzing the risk factors

Family history of heart disease: In the U.S. Nurses Health Care Study — the largest to date — having a father who suffered a heart attack before age 55, or a mother who had one before age 65, increased the risk.

Diabetes: Women with diabetes mellitus have CAD risks about three times those of non-diabetic women, even at a young age. Whether controlling blood sugar can decrease the risk is not known, although it is considered a reasonable strategy.

Blood cholesterol levels: Having high blood cholesterol increases CAD risks in both sexes but total blood cholesterol levels may be less critical in women than the type of cholesterol involved. Women seem better protected by “good” or high-density lipoprotein (HDL) cholesterol levels than men. To reduce heart risks, women can try to raise HDL by exercising vigorously, losing weight (if obese) and considering menopausal hormone replacement therapy, or possibly cholesterol-lowering drugs.

Triglyceride levels — if elevated, increase risks of heart attack.

Cigarette smoking increases risks 20-fold. About 70 per cent of heart attacks in pre-menopausal women occur in smokers, even without other risk factors. Taking birth control pills and smoking can be an especially dangerous duo.

Hypertension: High blood pressure is a major risk factor for early heart disease in both sexes. Men who cannot reduce their blood pressure with diet, exercise and smoking cessation are usually given blood pressure medication. But whether giving women drugs to reduce blood pressure will similarly reduce heart attack deaths is not yet clear. Some recent studies show a lowered coronary risk through blood pressure reduction using medications in women.

Obesity: Some, but not all, studies identify excess weight (20 per cent or more above ideal weight) as a risk factor. An ongoing U.S. nurses study finds that a gain of 11-18 pounds over the desirable weight raises heart attack risks in adult women by as much as 60 per cent. Other studies suggest that it is not the weight per se that counts, but how it’s distributed. “Apple-shaped” weight gain (on the belly) is considered more of a danger than the “pear-shaped” pattern (on the hips and thighs).

Hormone replacement therapy: can it reduce risks?

Menopausal hormone replacement therapy (HRT) may help to reduce heart risks in women. Before menopause, women have lower blood LDL (“bad”) cholesterol levels and more HDL (“good”) cholesterol than men. Following menopause, as estrogen levels drop, this pattern reverses: blood HDL goes down and LDL cholesterol rises. Hormone replacement therapy is said to bring a 10 to 15 per cent rise in HDL blood cholesterol and a corresponding drop in LDL, thereby helping to reduce deaths from heart disease — but the definitive results are not yet in. Women must balance the possible heart-protecting benefits of taking estrogen against the probable risks — namely an increased risk of breast, endometrial and ovarian cancer. (See Health News, June 1995, for details.

How about ASA/aspirin as a preventive?

Several studies show that taken regularly “an aspirin a day” — one 160-325 mg tablet of acetylsalicylic acid — can reduce the incidence of heart attacks in men. However, ASA’s effectiveness as a preventive in women is uncertain — although the Boston Nurses Study showed a reduction in heart attacks among female aspirin-takers. (Asa-users should take entero-coated products and must watch for side effects such as gastrointestinal bleeds, stomach ulcers and elevated risks of hemorrhagic stroke.

As always, prevention is best!

Since heart disease is a major killer and one third of those who suffer an MI die before reaching hospital prevention is a must. Many women worry about their father’s or husband’s hearts, neglecting their own. Women need to cultivate greater heart-awareness. As CAD takes years, even decades, to develop, the earlier women become “heart-wise” — eat a low-fat diet, exercise regularly and quit smoking — the better the chances for a longer, healthier life.

Ways to promote heart health and reduce risks

* Determine your corona risks and try to reduce them;

* Know the symptoms of a heart attack and what to do;

* Quit smoking: After five years, former smokers lower risks by 50-70 per cent;

* Achieve and maintain desirable weight;

* Have regular blood pressure checks and reduce hypertension (high blood pressure);

* Exercise regularly — at least three times a week (for 30 minutes) in the correct heart-rate zone for your age;

* Eat a cholesterol-reducing low-fat diet with enough fruit and vegetables rich in anti-oxidants (vitamins C, E and beta-carotene), possibly including soya products in the diet. (Experts say that eating 20 grams of tofu daily or its equivalent in soya milk can significantly protect the heart);

* Lower blood triglycerides by limiting intake of simple sugars (as in candies, honey, cakes);

* Discuss possible benefits of hormone replacement therapy;

* Insist on thorough investigation of heart symptoms;

* Consider regular low-dose ASA (Aspirin) as a preventive,

* Have all family members learn CPR (cardiopulmonary resuscitation) so you are prepared for emergency treatment until help arrives.

RELATED ARTICLE: What causes a heart attack?

A heart attack or myocardial infarction (MI) usually occurs because the lining of the coronary arteries, which lie on the heart’s surface and supply it with oxygen, became narrowed or blocked by fatty deposits (plaque), producing atherosclerosis. Progressive atherosclerosis reduces bloodflow to the heart and the consequent “ischemia” or oxygen lack causes symptoms such as angina (chest pain) and shortness of breath. Angina pectoris — from the Greek “to strangle” — is chest pain or heaviness due to lack of oxygen in the heart muscle, often brought on by exertion or stress. If the bloodflow and oxygen supply are cut off, parts of the heart muscle can be irreversibly damaged in less than one hour, so speed is essential.

RELATED ARTICLE: Classical signs of heart attack

* Persistent chest pain, possibly radiating to neck, jaw, left shoulder or arm;

* Sense of tightness or “squeezing” in the chest;

* “Heaviness” that may feel like indigestion;

* Sweating, nausea and vomiting;

* Pallor (pale skin);

* Shortness of breath;

* Denial — refusal to believe anything is seriously wrong.

RELATED ARTICLE: Gender bias in research

Most clinical studies are performed on young white males, possibly because they are the easiest to study, and women are under-represented. Women of childbearing age are excluded because of possible risks to a developing fetus. Elderly people are excluded because they often have other illnesses and are taking several medications that confuse the results. It has been generally assumed that, unless there is good biological reason to think otherwise, results in white men can be extrapolated to the rest of the population, but this is now being debated.

Whatever the reasons for the male-female imbalance, there are biological differences between the sexes that make it imperative to study women’s heart disease separately, or at least include them in the studies. Researchers are hastening to fill the gap and the U.S. Hearth, Lung and Blood Institute and Canadian Heart and Stroke Foundation have set guidelines for the better diagnosis and management of CAD in women.

RELATED ARTICLE: Current treatments for coronary heart disease

* Beta-adrenergic blockers or beta blockers — such as propanolol (Inderal) and metoprolol (Betaloc) to slow the heart rate and allow the heart to get along with less oxygen;

* Nitrates (e.g., nitroglycerin) — as tablets, patches or sprays to dilate the vessels;

* Calcium-channel blockers, to control angina (as an alternative to beta blockers, useful for some);

* Blood-thinning medications such as ASA (aspirin), to decrease blood clotting;

* Percutaneous Coronary angioplasty or ballooning, a procedure that inserts a thin plastic catheter with an inflatable balloon at its tip into the blocked artery to stretch the vessel wall and crush any clots, plaque or other obstructions. Sometimes a stent — small device to hold open narrowed arteries — is inserted;

* Thrombolysis — infusion of clot-dissolving substances during, or right after, a heart attack, to re-establish bloodflow and prevent heart-muscle damage (so-called “myocardial salvage”). Thrombolysis or “clot-buster” drugs such as the enzymes streptokinase and tissue plasminogen activator (tPA) are only helpful within the first six hours of an MI, so time is of the essence and the sooner the better.

* Coronary bypass surgery — to bypass severely blocked coronary arteries by grafting in new vessels — usually in restoring the heart’s oxygen supply and alleviating angina. Women can receive bypass operations with as good long-term results as men, although they have higher risks. (See Medical update: Recapping bypass surgery.)

RELATED ARTICLE: Tests for coronary artery disease:

* Electrocardiogram (ECG) — heart-pattern test using electrodes placed on the chest to delineate the heart’s electrical activity during contraction (pumping);

* exercise stress test — conducted on a treadmill to detect cardiac ischemia (oxygen lack) under stress (during exercise);

* Perfusion imaging scans — with injected radioactive thallium to assess myocardial bloodflow (to the heart muscle) or using technetium labelling to visualize the heart’s bloodflow — better than an exercise ECG for ruling out CAD in women;

* angiogram — dye injected into the coronary arteries through a catheter (fine plastic tube) to locate blockages;

* exercise echocardiography — an “echogram” of heart action taken during exercise.

For more information: Consult your local Heart and Stroke Foundation. Call 1-800-360-1557 for pamphlets about Women and Heart Disease.

COPYRIGHT 1995 Strategic Inc. Communications Ltd.

COPYRIGHT 2004 Gale Group