Atherosclerosis is hardening of a blood vessel from a build up of plaque. Plaque is made of fatty deposits, cholesterol, and calcium. It builds on the inside lining of arteries. This causes the artery to narrow and harden. It affects large and medium-sized arteries.
As plaque builds up it can slow and even stop blood flow. This means the tissue supplied by the affected artery is cut off from its blood supply. This often leads to pain or decreased function. This condition can cause a number of serious health problems. Depending on the location of the blockage, it can cause:
In addition, a hardened artery is more likely to be damaged. Repeated damage to the inner wall of an artery causes blood clots often form. The clots are called thrombi. They can lead to a further decrease in blood flow. In some cases, a thrombus may become so large that it completely closes off the artery. It could also break into clumps, called emboli. These clumps travel through the bloodstream and lodge in smaller arteries, blocking them off. In these cases, the tissue supplied by the artery receives no oxygen. It quickly dies. When this occurs in the heart, it is called a heart attack . In the brain, it is called a stroke .
Long-term atherosclerosis can also cause arteries to weaken. In response to pressure, they may bulge. This bulge is called an aneurysm. If untreated, they can rupture and bleed.