Coronary Heart Disease

What is coronary heart disease?

Coronary heart disease a condition in which proper circulation of blood and oxygen are not provided to the heart and surrounding tissue. This result is due to a narrowing of the small blood vessels, which normally supply the heart with blood and oxygen.

What is angina?

Angina pectoris, commonly known as angina, is severe chest pain due to ischemia (a lack of blood and hence oxygen supply) of the heart muscle, generally due to obstruction or spasm of the coronary arteries (the heart's blood vessels). Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries.

What is a heart attack?

A heart attack occurs when the blood supply to part of the heart is interrupted. This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, which is an unstable collection of lipids (like cholesterol) and white blood cells (especially macrophages) in the wall of an artery. The resulting ischemia (restriction in blood supply) and oxygen shortage, if left untreated for a sufficient period, can cause damage and/or death (infarction) of heart muscle tissue (myocardium).

What is atherosclerosis?

Atherosclerosis is a disease affecting arterial blood vessels. It is a chronic inflammatory response in the walls of arteries, in large part due to the accumulation of macrophage white blood cells and promoted by low density (especially small particle) lipoproteins (plasma proteins that carry cholesterol and triglycerides) without adequate removal of fats and cholesterol from the macrophages by functional high density lipoproteins (HDL), (see apoA-1 Milano). It is commonly referred to as a "hardening" or "furring" of the arteries. It is caused by the formation of multiple plaques within the arteries.


How can atherosclerosis cause heart disease?

Atherosclerosis narrows the lumen of the coronary arteries and increses heart pressure. Such an affected artery develops rough inner surfaces. This increases the risk of a blood clot being trapped in the artery. A blood clot that forms in the arteries is called thrombosis. If it occurs in t he coronary arteries, the supply of blood and oxygen to the heart muscles may be completely cut off. Without oxygen, the heart muscle cells may be damaged or die, and a heart attack occurs.

How can coronary heart disease be treated?

Occlusions in the coronary arteries can be treated with drugs and, increasingly, by a clever surgical procedure which does not involve cutting open the patient’s chest. Rather, a balloon attached to a fine wire is inserted into an artery in the leg. The balloon is then pushed through the arteries, up towards the heart until it reaches the narrow part of the coronary artery. The position of the balloon is constantly checked using X-rays. When it is in the right place, the balloon is inflated, opening up the artery and thus improving blood flow. The balloon is then pulled back out of the body.
Another way is a type of treatment called coronary bypass may also be used to improve the blood flow. This usually involves sewing a vein from the leg or artery from the chest to bypass the clogged section of an artery. The advantage is that there is no tissue rejection. Using a vein has a disadvantage in that the wall of the vein is not as thick as that of an artery, A vein also has valves, so it must be inserted in the correct direction to allow the blood to enter the heart muscles.

Resources and credits
En.wikipedia.org
Biology textbook

Done by:
Sean Tan, Soh Jun Wei, Lim Shi Zheng, Jeremy Lee