In our advanced society coronary artery disease and heart attacks have reached epidemic proportions. Unfortunately we are seeing it develop at a younger age. It is now common in the 40s and being seen more often in the 30s. It is not common in women until the late 50s.
The coronary arteries supply the heart muscle with blood and provide the nourishment for the muscle to contract so as to work efficiently as a pump. Coronary artery disease is due to the development of atheroma (a disease of the arteries). Arteriosclerosis or hardening of the arteries is closely related.
In atheroma there is a patchy accumulation of fats, mainly cholesterol, in the arteries. These plaques of fatty material may degenerate and become rough. Platelets (small, round bodies in the blood concerned with the formation of clots) may settle on the rough area and then a clot or thrombus forms.
The wall of the artery may thicken, narrowing the channel through which the blood flows. The localized clot may break off and flow on to block a smaller artery further on. This is an embolus. Or the clot may enlarge and completely block the artery where it first formed.
Several problems or symptoms
Angina is one. This is a chest pain due to narrowing or blocking of the arteries. When the person exerts himself his heart does more work and needs more oxygen. It doesn’t get it because of the obstruction to the arteries. Rest, by reducing the need, will relieve the pain. The drug nitroglycerin, also known as glyceryl trinitrate (GTN) which dilates the coronary arteries also relieves the pain.
It is often said that coronary pain can be diagnosed over the phone. In most cases that is true, as the pain is typical. Clinical examination by listening to the patient’s heart does not usually reveal much. The history is the most important part. The electrocardiograph (ECG) is also invaluable in this form of heart disease.
But there are times when the ECG shows no changes. In these cases the doctor must back his clinical judgment and this will depend on an accurate history. Sometimes the true picture may show on the cardiograph during or following exercise.
Coronary angiography is the ultimate investigation. A fine tube or catheter is inserted into an artery in the arm or leg and this is threaded along the artery to the opening where the coronary artery comes off the aorta, the main artery of the body. A radio-opaque dye is injected along the catheter and flows with the blood through the coronary arteries. X-rays then show whether they are normal, narrowed or blocked.
The risk factors associated with coronary artery disease are well established. But there is controversy about whether anything can be done about some of them. Perhaps the only factor that does cause disagreement among doctors is the level of lipids or fats to be found in the blood. These are cholesterol and triglycerides.
- Family history. If there is a family history of heart disease then we should increase our efforts to change these other factors.
- Obesity. It is unhealthy to be overweight at any age. Being fat also goes with an increase in the fats in the blood and losing weight may make these levels go down to normal.
- Smoking. There is nothing good to be said for smoking. All the evidence is against cigarettes. Pipe and cigar smoking are only moderately dangerous. This may be due not only to the fact that the smoke from these is not so often inhaled but also to the temperature at which the tobacco burns.
- Hypertension. Hypertension appears to be the major factor in older people. High blood pressure, however, can be controlled by drugs.
- High blood fats. There is no doubt that high fat levels in the blood are a major risk factor in coronary artery disease. Where the controversy arises is whether anything can be done about it.
- Stress. We are all subject to stress. Psychologists have divided us into type A (coronary prone) and type B (coronary resistant) personalities. The typical type A personality is dynamic, driving, competitive. We may not be able to change our personalities but we can learn to relax.
- Lack of physical exercise. Lack of physical exercise is associated with an increased risk of coronary artery disease. We can reduce that risk by exercising for 15 to 30 minutes at least three times a week.
How much can be done to prevent coronary artery disease?
Isometric type exercises or slow exercise that doesn’t get the heart pumping are of little use. Strenuous exercise once or twice a week in the unfit is dangerous and can cause a heart attack. Vigorous exercise lowers the level of fat in the blood.
Women over 30 who take the contraceptive pill and smoke have a greater risk of having a heart attack. This research has prompted a lot of hysteria. Many experts, both medical and lay, have suggested stopping the Pill. Few have suggested that these women stop smoking.
There is research to show that lowering the fat levels by diet or drugs will lower the risk. There is also research to show that it makes no difference. Some experts say that it makes a difference only before your first heart attack. But reducing your fat levels won’t prevent a second one.
What is the lay person to do when confronted with all this confusion? You can reduce weight, stop smoking, control your blood pressure, take more exercise, and learn to relax.
If your cholesterol and triglycerides are normal then eat what you like. If not, you ought to watch what you eat. But don’t keep rushing back to the doctor asking him to keep checking your cholesterol levels if you haven’t already eliminated those other five factors.