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P A R T 8  Drugs acting on the cardiovascular system

Gender considerations

BOX 47.3

Women and heart disease Until the late 1990s, heart disease was considered to be a condition that primarily affected men. Because of that belief, women were seldom screened for heart disease, and when they did experience acute cardiac events, they were not treated promptly or adequately. However, recent research has shown that heart disease is the leading cause of death among women, surpassing such diseases as breast and colon cancers.This finding has led to further research, still ongoing, about women and heart disease. Women enjoy a protective hormone effect against the development of coronary artery disease (CAD) until menopause, when oestrogen loss seems to rapidly increase the production of atheromas and the development of CAD. In several studies, women who received hormone replacement therapy (HRT) at menopause had a significantly reduced risk of CAD and myocardial infarction (MI) in the first few years after the onset of menopause. Research

showed, however, that after 5 years of HRT the incidence of MI and stroke rose sharply, leading to an early closure of the study. Studies have found that women experience different symptoms of heart disease—jaw and neck pain, fatigue and insomnia—and sometimes these are overlooked. HRT is not recommended as a means of reducing the risk of heart disease or stroke, although it is still recommended for the treatment of severe menopausal symptoms in the first few years after menopause. Women should be advised to reduce other cardiac risk factors by eating a diet low in saturated fats, exercising regularly, not smoking, controlling weight, managing stress, and seeking treatment for gout, hypertension and diabetes. Clearly, heart disease is not just a disease of men. Research will continue to offer healthcare professionals new information on preventing and treating heart disease in women.

■■ TABLE 47.2 Risk factors for coronary artery disease Unmodifiable risks Modifiable risks

Suggested modifications

Family history

Sedentary lifestyle

Exercise

Age

High-fat diet

Low-fat diet (polyunsaturated and monounsaturated fats)

Gender

Smoking Obesity

Smoking cessation

Weight loss

High stress levels Bacterial infections

Stress management Antibiotic treatment

Diabetes

Control of blood glucose levels Control of blood pressure

Hypertension

Gout

Control of uric acid levels

Menopause

Hormone replacement therapy (first few years of menopause only)

all of the small intestine. The chylomicrons pass through the wall of the small intestine, are picked up by the sur- rounding intestinal lymphatic system, travel through the system to the heart, and are then sent out into circula- tion. The proteins that are exposed on the chylomicron, called apoproteins, determine the fate of the lipids or fats being carried. For example, some of these packages are broken down in the tissues to be used for energy, some are stored in fat deposits for future use as energy and some continue to the liver, where they are further processed into lipoproteins. Lipoproteins The lipoproteins produced in the liver that have well- known clinical implications are the low-density lipoproteins (LDLs) and the high-density lipoproteins (HDLs) . LDLs enter circulation as tightly packed choles- terol, triglycerides and lipids—all of which are carried by proteins that enter circulation to be broken down for energy or stored for future use as energy. When an LDL package is broken down, many remnants or leftovers

need to be returned to the liver for recycling. If a person has many of these remnants in the blood vessels, it is thought that the inflammatory process is initiated to help remove this debris. Some experts believe that this is the underlying process involved in atherogenesis. HDLs enter circulation as loosely packed lipids that are used for energy and to pick up remnants of fats and cholesterol that are left in the periphery by LDL breakdown. HDLs serve a protective role in cleaning up remnants in blood vessels. It is known that HDL levels increase during exercise, which could explain why people who exercise regularly lower their risk of CAD. HDL levels also increase in response to oestrogen, which could explain some of the protective effect of oestrogen before menopause. Cholesterol The body needs fats, particularly cholesterol, to main­ tain normal function. Cholesterol is the base unit for the formation of the steroid hormones (the sex hormones, as well as the adrenal cortical hormones). It is also a basic