The Uniqueness of Heart Disease in Women
By Gordon A. Ewy, MD, Director Emeritus, University of Arizona Sarver Heart Center
In the United States, cardiovascular disease is the major cause of death in both men and women. While cardiovascular diseases in men and women share many similarities, there are distinctions requiring different diagnostic and therapeutic approaches. These differences are of increasing importance, for while the mortality of men with cardiovascular disease has been decreasing gradually since the mid-1980s, the mortality in women has been on the rise! Decades ago, heart disease in women was thought to be uncommon. Why was this?
♥ Pre-menopausal women tend to be spared from coronary artery disease, particularly if they don’t smoke, have diabetes, markedly abnormal cholesterol values or bloodclotting abnormalities.
♥ Women were less likely to be enrolled in early cardiovascular disease therapy studies, as women of childbearing age were excluded for safety concerns.
♥ In most of the early cardiovascular studies, individuals over age 65 were not included—they were the “elderly.” In retrospect, this prevented women from entering clinical trials at an age when their disease was most likely to become clinically apparent.
Because of the previous perception that heart disease was not a significant health problem in women, many doctors took the “Bikini approach” to women’s health care - screening only for breast and cervical cancer, often ignoring the risks of cardiovascular disease. However, a woman is 10 times more likely to die of cardiovascular disease than she is to die of breast cancer.
It Isn’t Your Father’s Angina
Both men and women experience angina (chest pain or discomfort) due to blockage in the coronary arteries that supply the heart muscle. Men are more likely to have a myocardial infarction (heart muscle damage due to complete blockage of a coronary artery) as their initial manifestation of heart disease.
In men, atherosclerosis (combination of cholesterol, scar tissue and inflammatory cells) causes angina by narrowing the coronary artery. In women, angina is often due to blockages caused by coronary spasm, in which the muscles in the coronary artery contract, making the artery smaller in one area and limiting blood flow to the heart muscle. This means coronary angiography, which is used mainly to look for blockage in the large coronary artery, often misses this cause of a woman’s angina. As a result, many women with positive stress tests and angina previously were told there was nothing wrong with their hearts because their coronary angiograms were normal.
However, angina in women also may be caused by blockages in the smallest of heart vessels which are not seen in coronary arteries during cardiac catheterization. Today, this microvascular disease can be diagnosed by sophisticated magnetic resonance imaging (MRI) cardiac chemical stress tests. Women’s symptoms make angina harder to detect. Recent studies have shown that unlike angina in men, most often characterized by chest or left-arm discomfort, angina in women often presents as weakness, fatigue, shoulder, stomach or back pain or shortness of breath. Treadmill electrocardiographic (ECG) stress tests are more likely to be falsely positive in women, contributing to diagnostic confusion. In one large study, 83 percent of men, but only 50 percent of women with positive ECG monitored stress tests had significant blockage in their coronary arteries.
Classic angina seems to be more benign in women. While 25 percent of men with angina suffered “heart attacks” within five years, heart attacks occurred in only 17 percent of women with angina. In all studies of heart attacks due to total or near-total blockage of a coronary artery, 75 percent were men and 25 percent women. Thus, the “classic” heart attack is three times more common in men; yet, when women do have a heart attack, their mortality rate is higher.
What are other distinctly different aspects of heart disease in women?
1. Stress often triggers heart dysfunction in women. Epitomized by expressions such as, “She died of a broken heart,” clinical observations of how some individuals experience severe stress or respond unusually to minor stress, have led to our understanding of a condition now called “stress cardiomyopathy.” In most studies, more than 90 percent of patients with stress cardiomyopathy are women, a condition associated with high levels of adrenalin, irregular or fast heart beating and heart failure. Fortunately, these are most often reversible. Tragically, the condition may result in sudden death in the most extreme cases—“She was scared to death.”
2. An abnormally stiff heart is often the cause of a woman’s heart failure. In men, heart failure is most likely due to damage of the heart muscle from one or more heart attacks, rendering the muscle weak and unable to contract normally. Heart failure in women, on the other hand, is often due to an abnormally stiff heart muscle—the heart contracts as it should, but is too stiff to relax normally and requires a higher amount of pressure to fill the major pumping chamber. This higher pressure backs up into the lungs, resulting in symptoms such as shortness of breath, especially with exertion.
3. Hypertension (high blood pressure) is more common as one gets older, and if inadequately treated, often leads to heart failure due to an abnormally stiff heart, a syndrome more common in women since they tend to live longer than men. Early treatment of hypertension is the best prevention, and research is needed to determine how best to prevent the abnormal heart “scarring” that comes with age, aggravating the condition.
What is optimal cardiovascular care for women?
First, the classic risk factors of high blood pressure, abnormal lipids, diabetes and others, which are often hereditary, need to be addressed. In addition, a healthy lifestyle is recommended, including appropriate diet, weight control, activity or exercise, not smoking and avoiding second-hand smoke. These risks and lifestyles are the same for men and women. The UA Sarver Heart Center is committed to discovering more about the unique qualities of heart disease in women. ♥
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