<P> From clinical trials, 20% is the average stenosis at plaques that subsequently rupture with resulting complete artery closure . Most severe clinical events do not occur at plaques that produce high - grade stenosis . From clinical trials, only 14% of heart attacks occur from artery closure at plaques producing a 75% or greater stenosis prior to the vessel closing . </P> <P> If the fibrous cap separating a soft atheroma from the bloodstream within the artery ruptures, tissue fragments are exposed and released . These tissue fragments are very clot - promoting, containing collagen and tissue factor; they activate platelets and activate the system of coagulation . The result is the formation of a thrombus (blood clot) overlying the atheroma, which obstructs blood flow acutely . With the obstruction of blood flow, downstream tissues are starved of oxygen and nutrients . If this is the myocardium (heart muscle) angina (cardiac chest pain) or myocardial infarction (heart attack) develops . </P> <P> The distribution of atherosclerotic plaques in a part of arterial endothelium is inhomogeneous . The multiple and focal development of atherosclerotic changes is similar to that in the development of amyloid plaques in the brain and that of age spots on the skin . Misrepair - accumulation aging theory suggests that misrepair mechanisms play an important role in the focal development of atherosclerosis . Development of a plaque is a result of repair of injured endothelium . Because of the infusion of lipids into sub-endothelium, the repair has to end up with altered remodeling of local endothelium . This is the manifestation of a misrepair . Important is this altered remodeling makes the local endothelium have increased fragility to damage and have reduced repair - efficiency . As a consequence, this part of endothelium has increased risk to be injured and to be misrepaired . Thus, the accumulation of misrepairs of endothelium is focalized and self - accelerating . In this way, the growing of a plaque is also self - accelerating . Within a part of arterial wall, the oldest plaque is always the biggest, and is the most dangerous one to cause blockage of local artery . </P> <P> The plaque is divided into three distinct components: </P>

Coronary artery disease that occurs in the extremities is called