Coronary Artery Disease

(CAD) Coronary Artery Disease

By Jessica Husted

NU 424

10/30/14

Coronary Artery Disease (CAD) is the most prevalent type of cardiac disease. It is the leading cause of death in the U.S. in both men and women. CAD, also known as atherosclerosis, is an abnormal buildup of lipid or fatty substances and fibrous tissue in the lining of arterial blood vessel walls. These substances cause blockage and narrow the coronary vessels in a way that reduces blood flow to the myocardium. Atherosclerosis involves a repeated inflammatory response to injury of the arterial wall and subsequent changes in the structure and properties of artery walls.

Atherosclerosis begins as fatty streaks of lipids that are deposited in the inner layer of the artery wall. It generally starts out early in life, possibly childhood. The development of atherosclerosis over many years involves an inflammatory response which begins with injury to the vascular endothelium. The injury can be initiated by smoking and hypertension. The presence of inflammation has many effects on the wall of the artery, and attracts inflammatory cells such as monocytes (macrophages). The macrophages ingest lipids, becoming “foam cells” that transport lipids into arterial wall. Activated macrophages also release substances that can further damage endothelium, attracting platelets and beginning clotting. Smooth muscle cells within vessel wall multiply and form a fibrous cap over a core filled with lipid and inflammatory infiltrate. These deposits, also called plaque, extend into the lumen of the vessel, narrowing and obstructing blood flow. Plaque can be stable or unstable, depending on how thick and inflamed the fibrous cap is. If the fibrous cap over the plaque is thick and the lipid pool stays relatively stable, then it can resist the stress of vessel movement and blood flow. But, if the cap is thin and there is continuous inflammation, then it becomes vulnerable plaque. The lipid core may...