Diagnosing atherosclerosis
Since atherosclerosis is a pathological or disease process rather than an illness in itself, your doctor wishes to establish whether you are at increased risk or whether you have already developed the clinical complications associated with it.The risk or predisposing factors have already been discussed. Part of a general medical examination is enquire into important lifestyle factors, such as:
- dietary habits
- evels of physical activity
- smoking habits
- the amount and kind of alcohol consumed
- less frequently, levels of stress during daily living
It is also important to determine whether the patient suffers from the important predisposing condition of diabetes mellitus or has already developed symptoms suggestive of early arterial obstruction without even noticing them, for example, erectile dysfunction in men. In women menstrual status is significant since risk increases substantially in post-menopausal women. Hypertension is usually symptom-free until a significant clinical complication results. The doctor also needs to know what medication you are currently taking.
After the history has been taken a physical examination will also help determine risk or the presence or absence of atherosclerosis. Since obesity is an important risk factor the doctor should determine your weight and height; the circumference of your waist and hip may also be measured. From this he can calculate important indices, such as, body mass index or waist:hip ratio which provide additional useful information. Hypertension is another significant contributory factor so blood pressure will be measured. Your heart will be assessed for size and normality of rhythm and the retina of your eyes examined for changes indicating arterial damage due to hypertension or diabetes mellitus. Your pulse should be felt in your neck, groin and legs in order to determine whether the arteries supplying these regions are normally functional. The doctor may also use his stethoscope to listen for the noise (bruit) made by blood passing over an atherosclerotic plaque. Skin colour, appearance and temperature also conveys important information regarding blood supply. Blood may be withdrawn after an overnight fast for what is often called a lipoprotein profile. This almost always includes total cholesterol, triglyceride and HDL-cholesterol and glucose determinations. Other less common assays may also be carried out. Urine should be examined for sugar and protein. If positive, or if other suggestive evidence is present, a glucose tolerance test and other assays may be performed to ascertain whether diabetes mellitus or some other predisposing condition is present. In women especially, reduced thyroid function, or hypothyroidism, is not uncommonly a cause of high cholesterol levels. Also tests may be done to determine menopausal status. There is also a host of other rarer disorders which may occasionally require specific investigation.
Of course, if the patient comes in the first place with obvious symptoms and features of one of the clinical complications of atherosclerosis already described, the doctor will then need to determine the extent and severity of the underlying process in order to recommend appropriate treatment. There is often no simple correlation between the severity of clinical symptoms and the extent and severity of atherosclerosis. In such cases, other complications such as thrombosis or even vascular spasm or embolism may have contributed to the presentation.
The extent of functional atherosclerosis is indirectly but usefully assessed by electrocardiography, at rest or during and after exercise. In addition, more direct assessment is increasingly possible through a series of sophisticated and expensive imaging techniques. These may involve catherisation and injection of a dye into a vein so as to visualize the coronary arteries or non-invasive techniques of various kinds which include ultrasound and X-rays amongst others.
Can atherosclerosis be prevented?
For most people clinically important atherosclerosis can be prevented or markedly retarded by means of lifestyle changes alone. In some, cholesterol-lowering medication may be required; and in a few it may be impossible at the present time.Lifestyle changes
- An appropriate diet
- regular exercise
- the elimination of harmful substances.
Diet and exercise work together in a synergistic fashion and can also help reduce stress which can contribute to clinical complications. The principles are easy to understand but putting these into practice can be difficult in Westernised countries. It requires commitment and understanding plus a refusal to be misled by a host of popular fads which promote specific foods or substances as the secret of success. These are almost universally ineffective and are occasionally harmful.
Principles of a healthy diet
Obesity contributes to atherosclerosis directly and indirectly. Most South Africans are overweight. In such people, loss of weight is important in lowering blood pressure, reducing the risk of diabetes mellitus in predisposed individuals and in reducing triglyceride and raising HDL– cholesterol (good) levels. These changes are strongly protective against atherosclerosis and its complications.Loss of weight is achieved by reducing energy intake, especially energy contained in fat, and by increasing energy expenditure through regular exercise. In addition to fat, over-indulgence in simple carbohydrates – eg. sugar, sweets and many soft drinks – also causes obesity. The worst way to approach weight loss is through crash diets; these result in large weight fluctuations, called cycling, and rarely have benefit. Besides weight normalisation, it is desirable to cut down on saturated fat and cholesterol intake. This can be accomplished by reducing the consumption of:
- red meats, the skin of poultry and, especially, processed meats such as salamis and polony
- full cream diary products including, full cream milk, most cheeses and yogurts, many pastries and desserts
- eggs or egg-based products in desserts, pastries and pies
- fried foods especially those cooked in repeatedly used oils.
