CORONARY ARTERY DISEASE

condition that results when the coronary arteries are narrowed or occluded, most commonly by atherosclerotic deposits of fibrous and fatty tissue. Coronary artery disease is the most common underlying cause of cardiovascular disability and death. Men are affected about four times as frequently as women; before the age of 40 the ratio is eight to one. Other predisposing factors are lack of blood supply; spasms in the coronary vessels, which cause and/or are caused by hypertension; diabetes; high cholesterol levels; adverse physical reactions to mental stress; and heavy cigarette smoking. The primary symptom is angina pectoris, a pain that radiates in the upper left quadrant of the body due to the lack of oxygen reaching the heart. A myocardial infarction (heart attack) is precipitated when the interior passage of an artery, usually already narrowed by atherosclerosis (see arteriosclerosis), is completely blocked by thrombosis (blood clot) or arterial plaque.

Nitroglycerin, beta-blockers, and calcium-channel blockers are often used for control of angina. Aspirin, with its ability to inhibit blood clots, cholesterol-lowering drugs (e.g., simvastatin), and estrogen replacement in postmenopausal women all appear to have a protective effect against eventual heart attack. If the buildup of plaque has progressed, an invasive or surgical procedure is often necessary, although a combination of a strict low-fat diet, stress management, and exercise has been found to reverse the disease. The most common procedure is angioplasty with a balloon catheter. The use of the balloon catheter often can be complicated by cracks or weakening of the walls of the vessels and may lead to rapid reclogging of the vessel. Another procedure is coronary artery bypass surgery, which splices veins or internal mammary arteries to the affected coronary artery in order to bypass the atherosclerotic blockage and supply blood to the heart muscle. A cold laser may be used to remove atherosclerotic plaques with bursts of ultraviolet light. It does little damage to the arteries and leaves the walls of the vessels smooth, without the burning and scarring created by hot lasers. Mechanical cutting devices, called atherotomes, are sometimes to ream atherosclerotic plaque material from the vessel in a procedure called atherectomy.

The Columbia Encyclopedia, Sixth Edition Copyright© 2004, Columbia University Press. Licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.

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