CHD

Coronary Heart Disease

Total UK Deaths 2007

Coronary heart disease 91,458

Stroke 53,186

Other CVD 48,643

Lung cancer 34,552

Colo-rectal cancer 16,025

Breast cancer 11,995

Other cancer 96,739

Respiratory disease 78,330

Injuries and poisoning 20,371

All other causes 115,852

In the UK today, around 2.6 million people are living with coronary heart disease, killing just over 90,000 people in 2007; more than double that of lung cancer or other respiratory disease. CHD is the most common cause of premature death in the UK, with almost 1 in 5 premature deaths in 2007 from CHD and related problems. Unsurprisingly, CHD costs the UK economy a total of about £9 billion a year.

Atherosclerosis is the cause of CHD, where deposits of fat and inflammatory cells build up in the walls of the coronary arteries. Gradual increase in these deposits or “plaques” reduces blood flow and will often present as angina. Angina is the painful sensation described by the patient due to a restriction in coronary blood flow. Angina typically occurs when the patient undergoes exercise, as the supply of oxygen and glucose is restricted. If the plaque in a coronary artery ruptures, the flowing blood around it clots which can block the artery- leading to a heart attack (or myocardial infarction - MI). Typical symptoms of an MI include, crushing chest pain, often radiating to the jaw or down the left arm, shortness of breath, nausea and vomiting.

Diet plays a relatively small role in promoting CHD, although a ‘healthy’ diet includes low quantities of saturated fat, and adequate supplies of fruit and vegetables. Additional vitamins, minerals and health food supplements do not confer any benefit. Nevertheless, recent studies have shown that fruit and vegetables can play a role as anti-oxidants, oxidation occurring as the deposits form within the artery wall. They also contain potassium which may help to control blood pressure and the aid the regulation of the heartbeat. Leafy and root vegetables also contain a lot of folate, essential for the formation of blood cells and to maintain levels of homocysteine; additionally, links have been established that high levels of homocysteine can contribute to the risk of CHD.

However, high salt levels in a typical diet have been proven to increase blood pressure. Increased blood pressure causes the heart muscle to work harder, causing them to grow larger- this causes some vessels to be obstructed and impairs the function of the heart. High blood pressure has also been linked to the accelerated development of plaques, further increasing the risk of myocardial infarction.

In contrast, the level of cholesterol in the blood increases the risk of MI greatly. High levels of low density lipoprotein cholesterol (or LDL) mean that cholesterol builds up in the coronary arteries quicker. This enhances the plague build up, narrowing the lumen of the artery itself and increasing the risk of plague rupture and heart attack In contrast, high density lipoprotein cholesterol protects the vessels from CHD. The role of dietary cholesterol’s in CHD however is slight, as only 25% of cholesterol in our bodies comes from diet. Nevertheless, when LDL is too high, it can be treated with drugs that reduce LDL levels, such as statins, which also restore HDL to a more normal level.

Since 1994 diabetes has doubled in men and increased more than two and a half times in women. .Men who have type 2 diabetes have a between a two and fourfold increase risk of CHD, with that risk raises to three to fivefold in women. Diabetes plays a relatively large role in the build up of plagues, as the increased levels of glucose within the bloodstream accelerate the plague build up leading to high chance of incident. Diabetes also increases the production of certain cholesterols which are then deposited in the walls of the arteries which also leads to plague growth acceleration.

CHD and genetics is a developing field and very little is known about the genetic links between the two. The genes which actually cause CHD are unknown, but in recent years defective genes have been found which increase production of body cholesterol, which code for faulty cholesterol synthesis or uptake. Family history is a very important factor and a patient being treated for chest pain with a family history of heart failure often signals heart problems above anything else.

In 2007, a third of all premature deaths in men were from CHD and a fifth in women, and a 60 year old woman with CHD and a 50 year old man in the same development on CHD as the woman potentially have the same chance of death. Part of the reason why women are less affected by CHD or have it set on later is the role of oestrogen. Due to the higher levels of oestrogen in the female body, it provides protection to the heart, not much is known about what is done exactly.

There are numerous risk factors for CHD, so there are multiple treatments depending on which risk factors are the most applicable. When blood pressure is too high, drugs called Beta Blockers are given which reduce blood pressure and also offer some protection to the heart. Statins act to reduce cholesterol and slow plaque build up, reducing the risk of another heart attack. After a heart attack, the area surrounding the coronary artery is often dead or damaged due to nutrient starvation (oxygen, glucose etc). The heart’s own function will have also been damaged, making it less efficient due to the scarring of the muscle- ACE (angiotensin converting enzyme) inhibitors work to restore the heart and improve its function. On the other hand, if a patient is admitted as an emergency they are given aspirin, an anti-platelet agent, which prevents the possibility of a clot forming again as it reduces platelet coagulation. Thrombolysis can also be used, where a drug such as Tissue Plasminogen Activator is injected intravenously to dissolve the clot and does so quickly. Angioplasty can also be used, where a wire with a small balloon is placed into the artery and inflated, widening the lumen and allowing blood to flow through the vessel again.

In terms of prevention, the best method of prevention of CHD is to stop smoking, estimates vary but smoking related deaths from CHD per year stand at approximately 25,000 deaths a year and regular exposure to second hand smoke increases the risk of CHD by 25%. Smoking contributes to existing plaques and will quicken Atherosclerosis further increasing the risk of episode. Following stopping smoking is a chance in diet and lifestyle, with little exercise and large amounts of fatty foods a change in diet can slow the growth of plaques. However, as stated before, diet plays a relatively small role and this can only do so much as the damage is already done

Sources

· http://www.ehow.com/how-does_5151206_high-pressure-cause-heart-disease.html

· http://www.bhf.org.uk/publications/publications_search_results.aspx?m=simple&q=chd+statistics

· Professor Martin Bennett

By Jonathan Bennett