Cardiovascular Disease - A Modern Day Epidemic

David Cowan

Cardiovascular Disease – A Modern Day Epidemic

Cardiovascular disease has been described as a ‘modern epidemic’, with it representing the second preventable cause of death in the United States of America, second only to smoking. The disease claimed 927,448 lives in 2002, that’s 38 percent of all deaths and it accounts for the most deaths worldwide.

Fig. 1.1 – Death Indictor – Nearly all these deaths were preventable.

The reason for cardiovascular diseases to be more prevalent in the developed world is our lifestyle. In 1998, 44 percent of all deaths in the developed world were because of cardiovascular diseases, compare that to the developing world, where we only see it at 29 percent. Our lifestyle is a major factor because of the food we eat and the way we conduct ourselves. With the collapse of the industrial sector in the UK – coal mining, steal manufacture – its not surprising that cardiovascular disease is rising. Computers have revolutionised the world, but they don’t afford the luxury of flexibility, with people working a 9 to 5 day it would be extremely difficult to get the required exercise.

It is a broad, sweeping term. It's not a single condition. Rather, it is a collection of diseases and conditions, with some types of cardiovascular diseases causing other types of cardiovascular disease - “Cardio” referring to the heart and “Vascular” referring to the blood vessel system.

These problems are usually the consequences of an arterial disease such as Atherosclerosis and Atheroma but can also be because of an infection or clotting problems. Atherosclerosis is the “hardening of the arteries" in which cholesterol and other deposits build up on the inner walls of the arteries, limiting the flow of blood however this is an over-simplification. Actually vascular lesions form on the vessel wall and may restrict or reduce blood flow to the lumen in the vessels. Theses are often known as atheromata or atheromatous plaques. This is where the inner layer of an unstable Atheroma breaks, compromising the structural integrity of the internal artery wall, the break may allow blood loss into the plaque, generate stenosis (Narrowing of a valve or an artery), embolism (The obstruction of a blood vessel by a foreign substance or a blood clot blocking the vessel), sometimes leading to severe morbidity and even possible death. Atheroma being a fatty deposit in the inner lining of the blood vessels.

There are many different forms and variations of cardiovascular disease,

Angina pectoris, - discomfort and chest pains, leading to an Angioplasty, a mechanical dilation of an artery that has been obstructed (PTA - percutaneous transluminal angioplasty) or a coronary artery bypass graft. Arteries or veins from elsewhere in the patient's body are grafted from the aorta to the coronary arteries, bypassing coronary artery narrowing caused by atherosclerosis and improving the blood supply to the myocardium (heart muscle).
Coronary heart disease or inflammation and obstruction of the coronary arteries. It is the end result of the build-up ...

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There are many different forms and variations of cardiovascular disease,

Angina pectoris, - discomfort and chest pains, leading to an Angioplasty, a mechanical dilation of an artery that has been obstructed (PTA - percutaneous transluminal angioplasty) or a coronary artery bypass graft. Arteries or veins from elsewhere in the patient's body are grafted from the aorta to the coronary arteries, bypassing coronary artery narrowing caused by atherosclerosis and improving the blood supply to the myocardium (heart muscle).
Coronary heart disease or inflammation and obstruction of the coronary arteries. It is the end result of the build-up of atheromatous plaques within the walls of the arteries that supply the myocardium.
Myocardial infarction (heart attack, and the acute stage of coronary heart disease)A Myocardial infraction is a sudden heart condition characterized by varying degrees of chest pain or discomfort, weakness, sweating, nausea, and vomiting, sometimes causing loss of consciousness. It occurs when a part of the heart muscle dies because of sudden total interruption of blood flow to a particular area; - the name is derived from “myo” meaning heart muscle and “cardium” referring to the heart.
Transient ischemic attacks - are caused by temporary disturbance of blood supply to a restricted region of the brain and cause recurring and brief neurological dysfunctions. If there are neurological symptoms persist for more than 24 hours it is classified as a Cerebrovascular accident or a stroke.
Peripheral artery disease - is a disease caused by the obstruction of large peripheral arteries.

Fig.1.2 – Clogged Artery – The plaque will build up then the blood will not be able to flow, starving vital organs and causing a heart attack.

But what causes all these diseases?

There is not one cause for these diseases but a multitude of factors. It could be that cardiovascular disease is hereditary, the patient may be smoking. He or she may have diabetes mellitus, generally overweight people or the intra-abdominal fat, hypertension, lack of exercise, and being male.

Tobacco smoke contains high levels of CO, carbon monoxide. Carbon monoxide affects the heart by reducing the amount of oxygen the blood is able to carry to vital organs. This means that the heart, lungs, brain, and other organs do not always receive enough oxygen to perform rudimentary functions. At the same time, nicotine causes an increase in heart rate and blood pressure. Over time, this causes “wear and tear” on the cardiovascular system. People who use tobacco are more likely to have heart attacks, high blood pressure, blood clots, strokes, haemorrhages, aneurysms, and other disorders of the cardiovascular system.

Another cause of cardiovascular disease is diabetes mellitus; which characterized by varying or importunate Hyperglycaemia or an increase in blood sugar levels. Hyperglycaemia can lead to dehydration and then to Ketoacidosis (Ketoacidosis is a type of metabolic acidosis [increase in acidity in blood plasma] which is caused by high concentrations of keto acids, formed by the removal of an amine group from a molecule.)

Reducing the amount of fat in your diet, particularly saturated fat, can help to reduce blood cholesterol levels. There is a strong link between high blood cholesterol levels and the risk of cardiovascular disease.

A trans-fatty acid is an unsaturated fatty acid molecule that contains a trans-double bond between carbon atoms, produced when plant-based oils are hydrogenated (a chemical reaction in which unsaturated bonds between carbon atoms are reduced by attachment of a hydrogen atom to each carbon. The process therefore results in the saturation of the carbon atoms) to produce solid spreads, such as margarines. They have been found to have the same effect on cholesterol levels as saturated fat.

However, not all fat is bad. Essential fatty acids such as omega-3s, which are found in oily fish, have been shown to further reduce the risk of cardiovascular disease.

Having a build of intra-abdominal fat can also be a contributory factor; intra-abdominal fat will build up in fatty deposits around the vital organs, increasing the risk of hypertension, strokes and diabetes.

Arterial hypertension or high blood pressure is where the blood pressure is constantly elevated. Persistent hypertension is one of the risk factors for strokes, heart attacks and heart failure, and is a leading cause of chronic renal failure (kidney failure).

Also pulmonary artery hypertension (PAH) is an increase in blood pressure in the pulmonary artery. Depending on the cause, it can be a severe disease with a noticeably decreased exercise tolerance and right-sided heart failure.

It has been called “the silent killer” because it usually doesn’t produce symptoms until a major organ is damaged.

Also if a person has a lack of exercise then basically they are not going to be burning off the fat, and it is going to deposit and cause a blockage in the blood vessels system causing a heart attack.

Men have a greater risk of heart attack than women do, and they have attacks earlier in life. Even after menopause, when women's death rate from heart disease increases, it's not as great as men's.

How do you prevent or “cure” Cardiovascular Disease?

It is pretty simple to prevent or “cure” cardiovascular disease; - you just need to take more exercise, cut down on animal fats and give up smoking, if you smoke. As soon as you stop smoking your body starts to repair its self from the devastating effects that smoking has caused.

A healthy diet is just as important to preventing the diseases. You should monitor your calories, cholesterol, fat, fiber and sodium levels. To help people the US Federal government issued a food pyramid (geographical locations isn’t an issue as it can work in UK)

Fig 1.3 – Food Pyramid - Maintaining a healthy heart will; prevent or manage other chronic diseases, assist in losing weight and boosting energy and promote overall good health.

For those with cardiovascular disease, treatment might involve using drugs to lower the blood pressure, decrease the risk of blood clotting, prevent abnormal heart rhythms, and decrease the cholesterol level and should that fail to produce results then a coronary artery bypass graft maybe necessary. If the heart is so badly damages or the graft fails then a heart transplant maybe needed.

Another way to prevent these diseases is to screen the population and find out those who are at risk of developing coronary heart disease; the best way to do this is to monitor the patients’ heart during exercise, screening can also be done by the doctor. Or you can encourage the country to adopt a healthier lifestyle, maybe with targeted advertising and promotions.

A preventable disease – cardiovascular disease is the biggest killer – diet, lifestyle and smoking are all major factors. So many simple precautions for prevention, yet so many deaths.

Bibliography

Biology 1 – OCR, Cambridge University Press