Coronary artery disease, as its also known, tends to run in families and is linked to smoking, lack of exercise, and a diet high in saturated fats, which tends to increase the level of blood cholesterol. It is a common cause of death in many industrialised countries; older men are the most vulnerable group. The condition is treated with drugs or bypass surgery. ‘Research shows that people who develop heart disease usually have one or more of the following: high blood cholesterol, high blood pressure, a history of cigarette smoking, diabetes mellitus, or an inherited (therefore genetic) tendency. They may also be obese (fat) and may not have exercised regularly.’ 3
‘Smoking is a major contributor increasing the likelihood of both thrombosis and atherosclerosis. A raised level of fat, especially cholesterol, in the blood is a major cause of atherosclerosis. Saturated fat of the type found in most meat and animal products, such as milk is particularly dangerous. High blood pressure or hyper intensive disease, a high level of salt in the diet and diabetes are factors which contribute to atherosclerosis and hence coronary heart disease.’ 4
‘Type 2 is the form of diabetes suffered from about 80% of diabetics. It develops when the body produces too little insulin due to malfunction of the beta cells or when the target cells fail to respond to insulin. …Diabetics have a 2-4 times greater than average risk of stroke (caused by damage to the arteries of the brain) and heart disease.’ 5 Diabetes increases the risk for hardening of the arteries, stroke and peripheral vascular disease. This occurs because diabetes changes body chemistry. As a result, blood may clot too easily; blood vessels may narrow, and fat may build up in the blood vessels faster. Two out of three people with diabetes die from heart disease and stroke. Therefore, people with diabetes must also manage blood pressure and cholesterol.
6
’Strategies for preventing the atherosclerosis associated with coronary heart disease include the following:
- Reducing cholesterol levels, triglyceride levels
and the use of fats and oils
- Stress management
- Quitting or abstaining from smoking
- Controlling high blood pressure (hypertension)
-
Controlling diabetes ’ 7
Coronary heart disease is the biggest single cause of premature death in the UK. It is the most common underlying cause of cardiovascular disability and death. Men are affected about four times as frequently as women; before the age of 40 the ratio is eight to one.
A number of interventions have been tried for coronary heart disease. Most effectively is bypass surgery – an operation called coronary artery bypass grafting (CABG) to replace narrowed sections of artery. ‘It splices veins or internal mammary arteries to the affected coronary artery in order to bypass the atherosclerotic blockage and supply blood to the heart muscle. A cold laser may be used to remove atherosclerotic plaques with bursts of ultraviolet light. It does little damage to the arteries and leaves the walls of the vessels smooth, without the burning and scarring created by hot lasers.’ 1 Mechanical cutting devices, called atherotomes, are sometimes to ream atherosclerotic plaque material from the vessel in a procedure called atherectomy. Plaque is made of oily molecules known as cholesterol, fibrous proteins, calcium deposits, tiny blood cells known as platelets, and debris from dead cells. Plaque formation often begins by adolescence and progresses very slowly over the course of decades. Gradually, the growing plaque thickens the wall of the artery, reducing the space available for life-giving blood to flow through
Another procedure is the endoscopic procedure, known as percutaneous transluminal coronary angioplasty (PTCA), involves the use of a balloon- tipped catheter to widen the diseased vessel. PTCA is cheaper and less invasive than CABG, but in roughly a third of cases further surgery is required in six months. The use of the balloon catheter often can be complicated by cracks or weakening of the walls of the vessels and may lead to rapid reclogging of the vessel.
References
- The Columbia Encyclopaedia, Sixth Edition. 2001. (CD ROM)
- Biology by Bill Indge page 31
- Biology by Marcus Barbor page 279
-
Understanding Biology for Advanced level 2nd edition, Glenn Toole 1991
- Biological sciences review, Nov 2002
-