If an artery becomes too narrow the tissue it feeds will first become ischemic (oxygen starved) and eventually will die (necrosis). Re-opening this artery is a time-critical procedure that happens every day in hospitals. Artery bypasses, stents, and angioplasty are all examples of procedures used to combat an atherosclerotic cardiovascular event.
Another cause of ischemia and necrosis is plaque rupture. Plaque deposits on arteries can rupture causing acute occlusions (blockages) of arteries. A tear or rupture will expose sub-endothelial tissue to blood cells and in so doing stimulate the formation of a clot. The clot is the body's attempt to seal off the crack but the clot itself can cause further obstruction to blood flow. This sudden increase in the blockage caused by the raised ruptured plaque and associated clot can transform a mild blockage into a critical one within a matter of hours. If it occurs within the blood vessels of the heart, the decrease in blood flow leads to severe and prolonged chest pain known as unstable angina. Such a patient is at obvious risk for a myocardial infarct should the blockage become any worse.
Atherosclerosis is found in most major arteries. Although it typically begins in early adolescence, it is asymptomatic until later in life. Therefore, we need cardiovascular risk markers to help assess patient risk. If an at-risk patient is identified early, the hope is that medication, lifestyle changes, or medical procedures can be used to avert a serious cardiovascular event. So, although the vast majority of us have some degree of atherosclerosis, risk markers can help identify those among us who are in more imminent danger or who have increased risk of an adverse cardiovascular event.