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CORONARY HEART DISEASE - ANGINA

What is Coronary Heart Disease ?

The heart is a pump with coronary arteries as its fuel supply pipes: the oxygen carried in the blood is its fuel. The coronary arteries narrow due to deposits of fat (arteriosclerosis) limiting blood flow to the heart muscle. If blood cannot get through to feed the heart muscle, then the heart cannot function properly because it lacks oxygen. Such a lack of oxygen in the heart causes pain called angina. The blood flow and oxygen supply may be alright if you are at rest. However, they are not adequate when the heart works harder, particularly with physical exercise and emotional stress. Pain may also occur at rest due to a temporary narrowing or spasm of muscle in the artery's wall.

Angina is a tight crushing or constricting pain usually felt in the chest over the breastbone, or on both sides. It may spread into the neck, shoulders, arms or back, and may just occur on one side. The pain usually lasts for only a few minutes. If it has occurred after a period of exercise, then the pain usually stops after a few minutes of rest. It is important to realise that considerable furring up of the arteries can occur even without angina, or indeed any other symptom. A heart attack (myocardial infarction or coronary thrombosis) may be, and often is the very first sign of coronary heart disease. It is almost always due to the development of a clot in a narrowed coronary artery.

How does Coronary Heart Disease occur ?

The arteries narrow due to fatty material accumulating in their walls. The cause of arteriosclerosis is not completely understood but many factors seem to speed it up. The most important is smoking. Raised blood pressure and diabetes also make it more likely to occur. Inactive people seem to get more coronary artery disease. Raised blood levels of fatty substances like cholesterol (particularly the part called LDL cholesterol) also play a part. This is often a result of a diet high in fat, particularly of animal origin. Stress of one form or another is thought to be a factor too.

Why does Coronary Heart Disease occur ?

The disorder is commonest in males beyond the age of 40. There is an inherited tendency, so that a family history of coronary disease increases the risk. Extra attention should be paid to those factors that can be changed. The exact way in which these factors actually lead to the furring up of the artery is not fully known.

Treatment Involved for Coronary Heart Disease

DIAGNOSIS

Although the pain is often very typical, you must have tests to confirm the diagnosis. The electrocardiogram (ECG-a recording of the heart's electrical activity) is the simplest, although it is not always helpful. An ECG during exercise on a treadmill or exercise bicycle may be more useful and may show up an abnormality not present while resting. Scans using small doses of radioisotopes such as thallium injected into the blood during exercise can help. However, this test is not always easily available. The most accurate test, cardiac catheterization, involves threading a small tube (catheter) from an artery in the arm or leg into the coronary arteries. An x-ray dye is injected, during x-ray filming, which shows up narrowings of the arteries (coronary arteriography). It is the most accurate test, but carries a small risk of producing a heart attack (myocardial infarction) or heart rhythm disturbance. It is undertaken only when precise diagnosis is essential. This may be when interventional treatment (see below) is being considered.

DRUG TREATMENT

Aims either to reduce the heart's need for oxygen or increase its supply. Reducing the heart's need does not help the underlying problem. Nevertheless it is the mainstay of treatment. Four types of medication are used. Beta-blockers relax the heart muscle so that it doesn't work so hard. There are many different varieties. The second group are nitrates. They make it easier for the heart to work by widening the arteries of the whole body. This means less work for the heart. Nitrates can be swallowed as tablets or absorbed through the mouth or skin. They must be used quite regularly and not just when pain occurs. Other nitrates are put under, or sprayed on to, the tongue. These varieties are used when the angina actually occurs, to shorten the attack. You can also use them before you undertake a task which you know might produce angina. The third group are called calcium antagonists. They block the movement of calcium in the heart's muscle cells and, like beta?blockers reduce the work that the heart needs to do. Finally there is a fourth group called potassium channel activators. They have a similar action to calcium antagonists; the only one in current use is nicorandil. In addition to these specific treatments for anginal pain, there are four types of drugs which may reduce the likelihood of the angina worsening. They have also been shown to reduce the risk of heart attack and its consequences. These are beta-blockers, low dose soluble aspirin (which reduces the stickiness of blood cells), the cholesterol lowering drugs called statins and ACE inhibitors (which help to relax the muscle in the wall of arteries). All four of these drug types may also be of value in patients who do not have angina but who are at special risk of coronary artery disease (such as people with diabetes). There may be reasons for not prescribing some of these drugs for some people : your doctor will discuss their use with you. There are several medications which have not been shown to be of benefit. These include vitamin E, selenium and chelation therapy. Chelation is an expensive technique for drawing minerals out of the blood.

INTERVENTION TREATMENTS

Physically improve blood flow to the heart muscle.. With coronary artery bypass graft surgery (CABG), a vein is removed from under the skin of the leg. It is used to bypass the narrowed segments of a coronary artery. Using arteries (such as the internal mammary artery which runs behind the breastbone) rather than veins seems to lead to better results. Arteries from the forearm may also be used instead of veins. In some instances by-pass surgery can be carried out on a single coronary artery without using a heart-lung machine; the incision may be smaller, the operation shorter and recovery quicker. The most recent interventional treatment is coronary angioplasty. Catheters with small balloons on the tip are passed into the coronary arteries as would be done in an arteriogram. They are positioned within the narrowed segments and are inflated. This stretches the narrowed part of the artery and allows more blood to pass through. Small tubes called stents are often used after the ballooning, to prevent the narrowing returning.

PREVENTIVE MEASURES

Are important and reduce your risk of having a heart attack. Daily low-dose aspirin is useful to reduce the build-up of blood clot in the artery wall. Treating any raised blood pressure, correcting an overweight problem, keeping diabetes under better control, correcting abnormal cholesterol levels and taking a more relaxed approach to life are all important. It is absolutely essential to give up smoking.

During Treatment for Coronary Heart Disease

Each type of drug may produce side-effects although serious problems are uncommon. Beta-blockers may cause fatigue, a tendency to low blood glucose levels if you have diabetes, or cause breathlessness. They can sometimes worsen heart failure and bronchial asthma. If there is a restricted blood supply to the legs, they can cause leg pains. They should be stopped or reduced if they cause dizziness. Nitrates, calcium antagonists and nicorandil may cause flushing sensations and nitrates often cause headaches. Calcium antagonists can also cause swelling of the feet. Pain which starts suddenly and is not relieved by resting or by nitrates under the tongue may be a warning to you of a threatening heart attack (when a narrowed artery blocks completely). It is important that immediate medical help is sought if angina worsens, occurs while at rest, or lasts for more than 20 minutes.

If Coronary Heart Disease is Left Untreated

Treatment aims to abolish pain. Untreated, the pain usually continues and may get worse. Sometimes it does improve by itself but if the pain is new or getting worse seek help without delay. Operating on your arteries in one of the above ways may be advised, particularly if your doctor thinks that there is a high risk of the artery blocking completely. Failure to have such intervention may make the likelihood of you having a heart attack that much greater. Heart attacks can be fatal.

Effects on Family of Coronary Heart Disease

Provided treatment is taken regularly and checks by the doctor are performed frequently, there should be little disturbance to your family. They should encourage you to stop smoking, reduce weight and take suitable exercise If coronary artery disease has occurred below the age of 50, and particularly if your cholesterol is raised, it is worth checking blood fat levels in your children, brothers and sisters. If found to be raised, they may be at risk of developing heart disease themselves and should seek medical advice.