IntroductionCoronary heart disease (CAD) is caused by reduced blood flow in the coronary arteries. This subsequently leads to reduced oxygenation of the myocardium, resulting in transient ischemia or angina. CAD can cause permanent damage to myocardial cells or heart attack. The left ventricle of the heart is most susceptible to CAD. Causes of CAD include atherosclerosis, congenital defects, coronary artery spasm, dissecting aneurysm, infectious vasculitis, and syphilis. Atherosclerosis and vasospasm are the most common causes of CAD, of which atherosclerosis is the most common. Pathophysiology Atherosclerosis Atherosclerosis is the hardening of the arteries. It occurs when fat, cholesterol and other substances build up in the walls of the arteries and form plaques. It mainly affects the intima of the arterial wall. The process of atherosclerosis begins when the body attempts to heal any irritation, damage, or injury to the endothelial lining. CAD progresses through three developments, which are fatty streak, fibrous plaque, and complicated lesion.(1) Fatty streaks contain atherogenic lipoproteins and macrophage foam cells. Streaking is caused by the development of fatty, lipid-rich lesions that result from the adhesion of macrophages to the intact endothelial surface of the vessel. The striations usually form between the endothelium and the internal elastic lamina of the vessel. Macrophages phagocytose lipids, produce fibrous tissue and stimulate calcium deposition, leading to a thickening of the intimal layer. The smooth muscle cells then migrate into the intima and become loaded with lipids. Lesions at this stage do not block the artery. However, the continuous cycle involves the transformation of the fat… in the center of the paper… as the other end is attached to the coronary artery distal to the arterial stenosis. On the other hand, LIMA is carefully dissected away from the chest wall. The distal end of the LIMA is anastamosed to the left anterior descending (LAD) artery while the proximal end remains attached to the left subclavian artery. Most CABG procedures use LIMA to bypass the LAD because it has greater long-term patency than an SVG. The use of LIMA is also associated with a higher rate of long-term survival. At the end of the procedure, the heart is restarted and the sternum is closed and held together with wires. After the procedure, patients typically require 1 to several days of intensive care unit management and then up to an additional week of additional care. Patients with poor exercise capacity before the procedure usually take longer to recover and regain good functional status.