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The American Heart Association (AHA) estimates that in 2007, approximately 700,000 people in the United States will have a heart attack for the first time. According to the AHA, episodes of angina based on age, gender and race are as follows:
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Age
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Gender/Race
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Annual Rates of New
Heart Attacks* per 1,000
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65-74
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Male, non black
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28.3
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Male, black
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22.4
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Female, non black
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14.1
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Female, black
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15.3
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75–84
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Male, non black
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36.3
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| Male, black |
33.8
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Female, non black
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20.0
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Female, black
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23.6
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85+
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Male, non black
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33.0
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Male, black
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39.5
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Female, non black
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22.9
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Female, black
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35.9
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*Source: AHA’s 2007 Heart and Stroke Statistical Update
Beyond genetics, a number of other risk factors may serve to either promote atherosclerosis or interrupt the disease process. Risk factors can be either controllable (e.g., diet, exercise and smoking) or uncontrollable (e.g., age, gender). To date, researchers have found that:
- Patients with unstable plaque deposits are at greater risk for a heart attack than those with compact, calcified plaque deposits. Some researchers have tried to develop methods to determine the degree of calcification, which may help predict the risk of heart attack.
- The risk of plaque rupture appears to increase in the morning hours, which may explain why more heart attacks occur between 6 a.m. and noon.
- People with chronic kidney disease tend to have high blood pressure, which places added stress on waste-removing filters in the kidney (nephrons). Uncontrolled high blood pressure also contributes to heart disease through a process known as remodeling, where there is enlargement and weakening of the heart’s left ventricle (left ventricular hypertrophy) and increased risk of heart attack. Research has found that heart attack survival decreases even with mild to moderate kidney disease.
- People with high levels of a certain type of lipoprotein called Lp(a) in the blood may be at increased risk of heart attack. Research has found that high Lp(a) levels may increase a person’s risk of heart attack over a 10-year period by as much as 70 percent.
- People with metabolic syndrome have been found to have double the risk for heart attack and stroke when compared to people without the syndrome. The characteristics of metabolic syndrome are elevated fasting blood glucose levels, abdominal obesity, high LDL (“bad”) cholesterol levels, high triglyceride levels and high blood pressure.
- Researchers have found a connection between infection and increased risk of heart attack. Infectious diseases, such as influenza, destabilize plaque and increase risk of plaque rupture. In some studies, influenza vaccines have been shown to reduce the risk of plaque rupture among the elderly, thus reducing the risk of heart attack and stroke.
The role of race in heart disease is currently being explored. In 2000, the Jackson (Mississippi) Heart Study was launched to better understand why black Americans have a higher mortality from heart disease than white Americans. Sponsored by the National Institutes of Health, it is modeled after the famed Framingham Heart Study. More than 6,000 black American men and women (ages 35 to 84) in Jackson, Mississippi, are being studied. A combination of physical examinations and questionnaires are being used to document and establish risk factors for cardiovascular disease in black Americans.
Totally vs. partially blocked arteries
Studies have indicated that a totally blocked artery is generally considered less of a threat in terms of a future heart attack than a partially or almost totally blocked artery. This is because there is less potential for further damage with the totally blocked vessel. The areas of the heart formerly supplied by that vessel are permanently scarred or “dead,” with no need for an oxygen-rich blood supply.
However, it is possible in some cases that the area served by the artery has collateral blood flow (i.e., blood flow through smaller caliber vessels) from another artery. In such cases, if it can be proven that the muscle is alive, opening or bypassing the artery may be of some benefit. Surgical bypass of a totally blocked artery that supplies a “dead” area of the heart may serve little or no purpose. Instead, the goal of the physician and the patient is to prevent further damage in those areas in which good or partial function still exists.
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