Cardiovascular disease is both the dominant health problem and the major cause of mortality for adult women in the US, claiming the lives of nearly 500,000 women annually. The staggering impact is that a US woman dies from cardiovascular disease almost every minute.
Although cardiovascular disease has traditionally been perceived to be a problem predominantly of men, since 1984, more US women than men have died annually from cardiovascular disease.The prominent reduction in cardiovascular mortality in the US reflects an effect in men, at least in part owing to the emphasis on preventive interventions in the male population. Of concern has been the limited awareness of the risk of cardiovascular disease for women, with little change in recent years.
A 1995 survey highlighted that four in five US women, and also one in three of their primary care physicians, were unaware of heart disease as the leading cause of death for women. Breast cancer was perceived as the major health problem. Despite contemporary public education campaigns by both governmental and voluntary health organizations, a 2003 survey by the American Heart Association (AHA) identified that only half of the women queried were aware that heart disease is their leading cause of death, with awareness among women of racial and ethnic minorities (who are at greatest risk for cardiovascular disease) lagging behind that of white women.
Of equal concern was that only a minority of respondents to the AHA survey were able to identify the major risk factors for coronary heart disease (CHD); obesity and sedentary lifestyle were cited as important by about 40% of women, with only a third identifying smoking, high cholesterol levels, or family history as risk factors, less than 20% listing hypertension, and only 7% noting diabetes.Widespread confusion was apparent regarding the role of menopausal hormone therapy in heart disease prevention. Unfortunately, a common assumption was that non-traditional methods such as vitamin use and aromatherapy were effective in cardiovascular disease prevention.
Magazines and television appeared to be the most common source of health information for women, with only about one-third of women actually having discussed heart disease and heart disease prevention with their physicians, the latter finding being more common for white than for racial and ethnic minority women.
Reinforcing the need for prevention is that women who develop clinical manifestations of CHD, particularly myocardial infarction or the need for coronary artery bypass graft surgery, do not fare as well as their male peers. Specifically, the mortality from acute myocardial infarction is almost twice as high among women younger than 65 years of age than for comparably aged men, with the mortality from coronary artery bypass graft surgery, particularly among younger women, double than that for their male peers.
Women following myocardial infarction are more likely to have a recurrent heart attack and more likely to die after hospital discharge than their male counterparts, with about one-third greater mortality for women within the first year following infarction. Disability from heart failure following a heart attack is more prominent for women than men.Worthy of emphasis is that coronary disease is not solely a disease of older women, in that 9,000 US women younger than 45 sustain a myocardial infarction each year. Thus the priority for coronary prevention is substantial for women of all ages.
A major national need is the education of women that heart disease is their major mortality risk and an important cause of health disability as well, with emphasis on the actions women can undertake to reduce their cardiovascular risk. Extensive public education campaigns are being mounted to encourage women to learn about their personal risk of heart disease, to participate in screening opportunities in order to identify their specific heart disease risk factors, and to undertake measures to decrease or reverse this risk.
Both nationally and internationally, the recent delineation that menopausal hormone therapy failed to provide cardiac protection, but rather was associated with increased cardiovascular and other risks, has served to refocus attention on both the lifestyle and the drug therapies documented to be beneficial in the prevention of cardiovascular and CHD in women.
AHA Evidence-based Guidelines for Cardiovascular Disease Prevention in Women
In 2004, the AHA, with 11 participating and co-sponsoring professional organizations, and with the endorsement of 22 additional healthcare and women's advocacy organizations, presented, both to women and to their healthcare providers, evidence-based guidelines for the prevention of cardiovascular disease.
The widespread dissemination of these guidelines should increase women's awareness of the pre-eminence of heart disease in their landscape of illness across the lifespan. Awareness is the initial step in saving lives. Women must realize that favorable lifestyle changes can effectively and substantially decrease both their risk of development of major cardiovascular risk factors and subsequently their risk of development of cardiovascular disease. This awareness and information empowers a woman to take charge of her personal health.
An important emphasis in the guidelines is that the intensity of preventive interventions is tailored to an individual woman's level of cardiovascular risk. Thus, she must consult with her healthcare provider to determine her personal risk level. For example, high-risk women include those who have had a heart attack or stroke, coronary angioplasty, or coronary artery bypass graft surgery and not, as often appreciated as the foregoing, women who have diabetes and those with chronic kidney disease.
Today, diabetes is considered a coronary risk equivalent, i.e. identifying that a woman with diabetes has the same risk of sustaining a coronary event as a woman already documented to have CHD. By contrast, a woman at low cardiovascular risk is one who does not smoke, who exercises regularly, who eats a heart-healthy diet, and has normal levels of blood pressure and blood cholesterol. She has less than a 10% chance of having a heart attack in the course of the next decade and must be encouraged by her healthcare provider to continue her heart-healthy lifestyle.
The AHA guidelines involve a set of recommendations for the prevention of cardiovascular disease in women aged 20 or older, and identify recommendations applicable over a broad range of cardiovascular risk.This concept allows clinicians to stratify women according to their baseline level of risk and to gauge the intensity of the interventions accordingly. This approach offers the opportunity to refocus the patterns of clinical practice in the US, to appropriately address the unique preventive, diagnostic, and management needs of women, designed to enhance their heart health.
Another important feature of the AHA guidelines is the strength of the recommendations, i.e. a classification based on the efficacy and the quality of the scientific evidence documenting this efficacy. It is increasingly appreciated that women have been either excluded from or under-represented in many clinical trials of cardiovascular disease prevention and therapy. Thus, when such studies were performed only in men, or when women were under-represented in the populations studied, the guidelines include an index of how far the available data can be generalized to women, allowing extrapolation of the best contemporary data to enhance the heart health of women. Guideline recommendations are categorized as:
- lifestyle interventions;
- major risk factor interventions; and
- preventive drug interventions.
An important section addresses interventions classified as 'not recommended', i.e. interventions that have not been shown to provide benefit and that may entail harm.
Lifestyle Interventions
Warranting high priority in clinical practice for women in all categories of cardiovascular risk are lifestyle interventions. These include strategies such as smoking cessation (including avoidance of environmental tobacco); regular physical activity (encouraging women to accumulate a minimum of 30 minutes of moderate intensity physical activity on most days of the week); a heart-healthy diet that includes a variety of fruits, vegetables, grains, low-fat or non-fat dairy products, fish, legumes, and sources of protein that is low in saturated fat; and weight maintenance or reduction with the goal of maintaining or achieving a body mass index (BMI) between 18.5 and 24.9kg/m2 and a waist circumference of less than 35 inches. All these interventions have a Class I recommendation, i.e. identifying their usefulness and effectiveness.
Major Risk Factor Interventions
Detailed recommendations address both the use of lifestyle interventions and pharmacotherapy to control elevated levels of blood pressure and to reduce elevated levels of low-density lipoprotein (LDL) cholesterol, triglycerides, and non-high-density lipoprotein (HDL) cholesterol and to raise levels of HDL cholesterol.
Specifically, the optimal blood pressure level is identified as <120/80mmHg, with initial attainment through lifestyle approaches, and use of pharmacotherapy when blood pressure cannot be controlled with this initial approach. Optimal levels of lipids and lipoproteins in women include a LDL cholesterol below 100mg/dL, a HDL cholesterol >50mg/dL, a triglyceride level <150mg/dL, and a non-HDL-C level (total cholesterol minus HDL cholesterol), below 130mg/dL. Again, initial lifestyle approaches are encouraged, with more intensive dietary intervention and pharmacotherapy recommended when optimal lipid levels cannot be attained. The most intensive interventions are directed toward the high-risk women.
Also targeted is the attainment of a normal hemoglobin A1-C level (<7%) in women with diabetes. Again, because of their high cardiovascular risk, more precise control of blood lipids and of blood pressure is recommended for diabetic women than for healthy women.
Preventive Drug Interventions
Aspirin is routinely recommended for high-risk women without a specific contraindication to its use, and for women described as at 'intermediate' risk when the blood pressure is controlled and the benefit is likely to outweigh the risk of gastrointestinal side-effects. Beta-blocking drugs should be used indefinitely for all women who have had a heart attack or for women with chronic ischemic syndromes.
A category of drugs known as angiotensin converting enzyme (ACE) inhibitors should be used in high-risk women unless contraindicated. Angiotensin receptor blocking drugs are recommended for high-risk women with clinical evidence of heart failure or decreased left ventricular function or in women who are intolerant to ACE inhibitors.
A new aspect of the guidelines addresses stroke prevention in women with the arrhythmia described as chronic or paroxysmal atrial fibrillation (AF).For women at high risk of stroke, anticoagulation with warfarin is advised.Aspirin is an alternative therapy for women considered to be at low risk for stroke or at high risk of bleeding or who have a specific contraindication for warfarin therapy.
Interventions Not Recommended
This category, known as Class III recommendations, describes interventions not shown to provide benefit and with the potential for harm. The recommendation is that estrogen plus progestin menopausal hormone therapy should not be initiated or continued for the prevention of cardiovascular disease in menopausal women. At the time of issuance of these guidelines, the recommendation was that other forms of hormone therapy, such as unopposed estrogen, should not be initiated or continued for prevention of cardiovascular disease in menopausal women, pending the result of on-going trials. Shortly thereafter, the Women's Health Initiative prematurely discontinued the estrogen-only arm of this prevention trial because of lack of cardiovascular benefit and an increased risk of stroke.
Although food-based antioxidants are advised as a component of a heart-healthy diet, antioxidant vitamin supplements are not recommended for the prevention of cardiovascular disease, again pending the results of ongoing clinical trials.
Finally, the routine use of aspirin is not recommended for lower risk women, pending the results of on-going trials, because the risk of bleeding in such women may outweigh potential benefits.
Summary
Cardiovascular preventive interventions have the potential to retard the development of cardiovascular risk factors and the subsequent substantial morbidity and mortality of CHD in women.The AHA Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women1 (Circulation 2004; 109: 672-693) offers both women and their healthcare providers a clear, evidence-based roadmap for cardiovascular prevention that is likely to improve the national heart health of women.