What is Atherosclerosis?

Atherosclerosis (also known as 'thickening of the arteries') is a blood vessel disease that is a major cause of heart attack and stroke.
Healthy Blood Vessel Arteries supply blood to all body organs, including the brain, heart and muscles. Healthy arteries have walls that are relatively thin and elastic.

The artery walls expand and relax in order to distribute blood pumped by the heart evenly. Arteries also help increase blood flow to parts of the body when needed, such as the legs when walking.

Early Stages

During the early stages of atherosclerosis, fat accumulates within the arteries. This process is clinically silent (no symptoms are experienced) and many people already have the disease in teenage years.
These deposits of fat are called lesions or plaques. Macrophages (a type of white blood cell) come into the plaque and try unsuccessfully to clean away the fat and cholesterol. Some of the fat goes rancid. Smooth muscle cells try to fix the damage by making more artery wall material and so the wall gets thicker and thicker.
The presence of fat and macrophages in the artery wall weakens it. These plaques keep increasing in size and distribution throughout our lives. As people age, more and more have lesions that are entering the later stages of atherosclerosis.

Later Stages

As the plaques of atherosclerosis get larger, many different symptoms can arise. The plaques can restrict blood flow so that the organs no longer get enough blood. For instance, shooting pains in the leg muscles when walking vigorously can be due to atherosclerosis in the arteries that supply the legs with blood. While these symptoms may cause discomfort they are not necessarily life threatening.
In contrast, the weak lesion wall can rupture, forming large or small blood clots, which can obstruct the blood flow severely and rapidly. It is the lack of blood flow to vital areas of the heart or brain that leads to the symptoms of a heart attack or a stroke. It is important to seek medical help quickly if someone experiences a heart attack or stroke, as doctors can often dissolve the clot and prevent much of the long term damage.