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.

artery, blood vessel that conveys blood away from the heart. Except for the pulmonary artery, which carries deoxygenated blood from the heart to the lungs, arteries carry oxygenated blood from the heart to the tissues. The largest arterial trunk is the aorta, branches of which divide and subdivide into ever-smaller tubes, or arterioles, until they terminate as minute capillaries, the latter connecting with the veins (see circulatory system). Other important arteries are the subclavian and brachial arteries of the shoulder and arm, the carotid arteries that lead to the head, the coronary arteries that nourish the heart itself, and the iliac and femoral arteries of the abdomen and lower extremities. The walls of the large arteries have three layers: a tough elastic outer coat, a layer of muscular tissue, and a smooth, thin inner coat. Arterial walls expand and contract with each heartbeat, pumping blood throughout the body. The pulsating movement of blood, or pulse, may be felt where the large arteries lie near the body surface.

or ischemic heart disease

Progressive reduction of blood supply to the heart muscle due to narrowing or blocking of a coronary artery (see atherosclerosis). Short-term oxygen deprivation can cause angina pectoris. Long-term, severe oxygen depletion causes a heart attack. Coronary bypass or angioplasty is needed if medication and diet do not control the disease.

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Surgical treatment for coronary heart disease to relieve angina pectoris and prevent heart attacks. It became widely used in the 1960s. One or more blood vessels—usually an artery in the chest or a vein from the leg—are transplanted to create new paths for blood to flow from the aorta to the heart muscle, bypassing obstructed sections of the coronary arteries.

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Vessel that carries blood from the heart to other parts of the body (see cardiovascular system). Arterial blood carries oxygen and nourishment to tissues; the one exception is the pulmonary artery, which conveys oxygen-depleted blood from the heart to the lungs for oxygenation and removal of excess carbon dioxide. Arteries are muscular, elastic tubes that transport blood under the pressure of the heart's pumping action, which can be felt as the pulse. Large arteries branch off from the aorta and give rise to smaller arteries, down to the threadlike arterioles, which branch into capillaries. An artery wall's inner layer (tunica intima) consists of an endothelial (cellular) lining, a fine connective tissue network, and a layer of elastic fibres. The middle layer (tunica media) is mostly smooth muscle cells. The outer layer (tunica externa) contains supportive collagen fibres. Seealso capillary; vein.

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