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Coronary atherosclerosis is an inflammatory disease characterized by the accumulation of white blood cells, cell debris, fatty substances (cholesterol and fatty acids), calcium, and fibrous tissue (plaque or atheromas) on the walls of the coronary arteries that supply the heart muscle. As plaque slowly increase in size over many years, the artery narrows in places (stenosis), and blood flow to the heart is reduced. Cholesterol-containing plaques are highly dangerous even without narrowing of the vessel because the fibrous cap can be softened and rupture suddenly during acute heavy exercise or activity (e.g., extreme athletic effort, shoveling snow). This can cause bleeding from the blood vessel wall, resulting in blood clot formation that may obstruct the vessel. The stenosis may become so significant that the blood supply is inadequate to meet the needs of the heart (myocardial ischemia), and the affected part of the heart muscle no longer functions normally. Myocardial ischemia typically results in chest pain (angina pectoris), but may also cause no symptoms (silent ischemia). Total blockage of a coronary artery results in a heart attack (myocardial infarction).
Risk: Risk factors for coronary atherosclerosis include male gender, advanced age, family history of atherosclerosis particularly before age 50, high blood pressure (hypertension), diabetes mellitus, a high level of total cholesterol and/or a high level of low-density lipoprotein (LDL) cholesterol and a low level of high-density lipoprotein (HDL) cholesterol (dyslipidemia). Other risk factors include high levels of certain fats (triglycerides) in the blood especially among women, smoking and exposure to second-hand smoke, obesity and poor physical fitness. Emotional stresses including hostility, anger, depression, and anxiety are thought to predispose individuals to developing coronary artery disease. The term “metabolic syndrome,” encompasses many risk factors for coronary atherosclerosis, including obesity, hypertension, insulin resistance, and dyslipidemia.
Among individuals younger than 65 years who do not smoke, coronary atherosclerosis is primarily a disease of men. This difference in early risk is attributed to the protective effects of estrogen for women before menopause (Pearlman). Increased age becomes a risk factor for both sexes later in life. Men older than 45 years and women older than 55 years are at increased risk for developing coronary atherosclerosis (“Coronary Artery Disease”).
Research continues into additional risk factors that may contribute to the development of coronary atherosclerosis. Untreated sleep apnea (the abrupt starting and stopping of breathing during sleep) is believed to increase risk of hypertension and diabetes and is often the origin of a stroke. Inflammatory disease processes, such as the development of rheumatoid arthritis, may predispose individuals to developing coronary artery disease. Tests for elevated levels of C-reactive protein (CRP) in the blood, indicative of inflammation developing somewhere in the body, may help identify individuals at increased risk as may tests for elevated levels of the amino acid homocysteine.
In contrast to high LDL cholesterol ("bad" cholesterol), high levels of high-density lipoprotein (HDL) cholesterol ("good" cholesterol) decrease the risk for developing coronary atherosclerosis. Incidence and Prevalence: Coronary atherosclerosis is the most common form of heart disease and the leading cause of death for both men and women in the US (“Coronary Artery Disease”). It accounts for 650,000 deaths and is a factor in 1.25 million myocardial infarctions in the US each year (Pearlman). |