Cardiovascular Diseases

Cardiovascular diseases are :

- degenerative diseases of the heart and circulatory system

- They are a major cause of death and disability

- They are responsible for 20% of all deaths worldwide and up to 50% of deaths in developed countries.

Cause :

- Atherosclerosis

> hardening and narrowing of the arteries

> This progressive process silently and slowly blocks arteries, putting blood flow at risk.

> The cause of heart attacks, strokes, and peripheral vascular disease

        What Causes Atherosclerosis?

- Arteries are blood vessels that carry blood from the heart throughout the body.

- They're lined by a thin layer of cells called the endothelium.

- The endothelium works to keep the inside of arteries toned and smooth, which keeps blood flowing.

- Atherosclerosis starts when high blood pressure, smoking, or high cholesterol damage the endothelium,

- At that point, cholesterol plaque formation begins.  

Cholesterol invasion

- Bad cholesterol, crosses damaged endothelium.

- Cholesterol is a lipid which is needed for the synthesis of vitamin D in the skin, steroid hormones in the ovaries, testes and adrenal glands and, in all cells, plasma membranes.

- However, cholesterol dangerous if it in excess.

- The cholesterol enters the wall of the artery.

Plaque formation

- Your white blood cells stream in to digest the cholesterol.

- Over years, the accumulating mess of cholesterol and cells becomes a plaque in the wall of the artery.

- Making the arteries less elastic and restricting the flow of blood.

- Plaques grow within the artery wall and push inwards reducing or blocking the passage of blood.

- The plaque may break through the lining of the artery to give a rough surface.

Thrombus and Thrombosis

- thrombus happened when the blood can no longer flow smoothly and tend to clot

- thrombosis happened when the tissues are starved of oxygen and nutrients

Atherosclerosis and Plaque Attacks

Plaques from atherosclerosis can behave in different ways :

- They can stay within the artery wall

> There, the plaque grows to a certain size and stops

> Because they don't block blood flow, these plaques may never cause any symptoms

- They can grow in a slow, controlled way into the path of blood flow.

> they cause significant blockages.

> Pain on exertion (in the chest or legs) is the usual symptom.

- Plaques can suddenly rupture, allowing blood to clot inside an artery.

> In the brain, this causes a stroke; in the heart, a heart attack.  

Stroke

- occurs when an artery in the brain bursts so that blood leaks into blood tissue (a brain haemorrhage) or,

- when there is a blockage in a brain artery due to atherosclerosis or a thrombus

- The brain tissue in the area supplied by the artery is starved of oxygen and dies (cerebral infarction)

- They can be instantly fatal or severely disabling to the victim

- it depends on how much of the brain is affected.

Coronary Heart Disease

- It is a disease of these arteries that causes damage to, or malfunction of, the heart.

- a result of plaque buildup in your coronary arteries (atherosclerosis) that leads to blockages.

- The arteries, which start out smooth and elastic, become narrow and rigid, restricting blood flow to the heart.

- The heart becomes starved of oxygen and the vital nutrients it needs to pump properly.

- We can say that the coronary heart disease develops if the blood supply to the heart muscle is reduced.

3 forms of coronary heart disease :

- Angina Pectoris
Symptom :

> Severe chest pain brought on by exertion

> The pain starts when excercising, but goes when resting

> The pain is caused by a severe shortage of blood to the heart muscle, but there is no death of hearts tissue.

- Heart attack

> Also known as myocardial infarction

◦

when a large enough branch of the coronary artery is obstructed by a blood clot, part of the heart muscle starved of oxygen and dies.

> This causes sudden and severe chest pain

> A heart attack may be fatal, but many people survive if they are traeated immediately

- Heart failure

> Due to blockage of a main coronary artery and the resulting gradual damage of heart muscle.

> The heart weakens and fails to pump efficiently.

Epidemiological evidence

- Coronary heart disease remains a major killer across the world in 2008, and is most prevalent in Russia, and least prevalent in Japan (counting only the developed world).

- Coronary heart disease death rates differ also within countries, and between socio-economic stratas

- In the UK, the incidence of the disease is highest :

> in Scotland, Northern Ireland and the north and north-west of England

> among poorer people

> among certain ethnic groups including south Asians

> among men

- This data tells us that people are not equally at risk of developing Coronary Heart Diseases.

Risk Factors :

Table 1: Risk

Risk factor	Effect
Alcohol	Causes high blood pressure, this and high intake to increase risk of atherosclerosis. Risk may decrease with moderate intake.
Age	Risk increases as age increases
Blood cholesterol	Direct relantionship between high cholesterol concentration and CHD risk
Diabetes	Anyone with diabetes is at increased risk
Diet	Risk increases with high intake of saturated fat and/or salt, since these factors increase the risk of atherosclerosis. Decreases risk for antioxidants, soluble fibres and moderate amounts of unsaturated fats.
Heredity	Genetic predisposition does exist, and genes can cause people to develop high blood cholesterol concentrations.
High Blood Pressure	Risk increases with increasing blood pressure.
Gender	Men are at greater risk than women
Level of exercise	Risk decreases if more exercise is done, aerobic activity helps to control blood cholesterol and obesity. Lowers blood pressure.
Obesity	Being obese greatly increases risk, Puts a strain on the heart and rises blood pressure
Social Class	Poverty increases the risk
Smoking	Combines with all other risk factors to multiply the chances of developing coronary heart disease.

Prevention

- take more exercise

- give up smoking

- reduce the fat in their diet

Cure

- Treatment includes drugs to reduce blood clotting, lower blood pressure and decrease the concentration of cholesterol in the blood

- operation by takes a blood vessel from else where on the body, and attaching it to the coronary artery, 'by-passing' the clot in the artery blockage

- a complete heart transplant may be given,
but this is very difficult to since a donor must be found that matches the recipients tissues etc.

- Heart transplants are usually refused to people who have not completely given up drink and smoking, in an effort to improve the health of the waiting list and to ensure that the few hearts they do get are not then ruined.