The lining of healthly blood vessels is smooth and uniform, allowing blood to flow with little difficulty. Atherosclerosis is the medical term for "hardening of the arteries" and is a blood vessel disease that is characterized by deposits of fat along the lining of the blood vessel wall. Sometimes the disease is called arteriosclerosis, a word that means narrowing of the arteries.
Fatty deposits can reduce the inner diameter of the blood vessel (called the lumen). This can reduce the amount of blood that can flow through the vessels, making it harder to carry oxygen to the organs and tissues. Fatty desposits can also stimulate the formation of clots along the blood vessel wall. Clots can become large enough to completely plug up the blood vessel and prevent any blood from flowing through it. Clots can also break a part and travel in the circulation until they plug up a smaller blood vessel that is downstream.
When fatty material builds up within the blood vessel wall, it is harder for the blood vessel to relax. This can lead to high blood pressure. When the blood pressure is high, the heart has to work harder to pump blood into the stiffer (or more resistant) vessels. Overtime, this can overwork the heart muscle ad lead to damage.
Fatty deposits in the blood vessel wall can damage the lining and lead to a weakening within the wall. The weakened area can bulge outward creating an aneurysm. Aneurysms can eventually become weak and rupture, causing serious blood loss.
Over time, atherosclerosis affects virtually every organ in the body. If the blood vessels leading to certain organs becomes narrowed from disease, the organ can suffer from a lack of oxygen (called ischemia). If a blood clot blocks the flow through a vessel, the oxygen supply to the organ can be stopped completely, causing some of the tissue to die. This the most common reason for a heart attack or stroke.
Atherosclerosis is a very common problem that afflicts many Canadians. A high fat diet, smoking, diabetes, inactivity and gentics are risk factors for developing atherosclerotic disease.
Ischemia is a word used to describe a situation where there is not enough oxygen reaching the cells of the body. If the blood flow to the heart muscle is inadequate, cardiac ischemia can occur. Ischemia can cause chest pain. Chest pain due to ischemia is called angina. Blood flow to narrowed vessels can be improved by coronary artery bypass surgery or coronary angiography.
If the heart muscle is deprived of oxygen for a prolonged period of time, an area of the heart muscle can die. Dead muscle is called an area of "infarction". When an area of the heart muscle dies, it is called "Myocardial Infarction" or an "MI".
ABOVE: Narrowing of a blood vessel due to atherosclerosis.