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Coronary heart disease (CHD)

Case study: 'I was lucky it was Boxing Day. There was less traffic and the ambulance was able to get to the hospital more quickly.'

What is it?

Man on sofa Coronary heart disease (CHD) refers to disease of the arteries that supply blood to the heart muscle, which in turn damages the heart. This section focuses on the two most common aspects of CHD: angina and heart attacks.

To understand CHD, you need to know that the heart is a muscular bag divided into four chambers. Its function is to send blood to the lungs to receive oxygen and then to pump this oxygen-enriched blood around the body to all the vital organs, e.g. the kidneys, liver and brain. All muscles need a blood supply and the heart is no exception — the coronary arteries supply the heart muscle with all the blood it needs to do its job efficiently.

What are the main symptoms?

Angina

When CHD begins, the coronary arteries become progressively furred up with a fatty substance called atheroma. There are no symptoms at first but as the situation worsens, chest pain develops during physical activity as the coronary arteries are unable to supply enough blood to the heart muscle — this is called angina.
Pain is usually found in the upper chest and most sufferers say it feels like a heavy weight or squeezing sensation that eases off during rest.
This pain may also be felt in the neck, shoulders, arms or back and is frequently mistaken for indigestion, but the relationship with exertion is the key feature that points to a cardiac cause.
Angina can also come on when walking after a heavy meal or against a cold wind or when angry or stressed.
As the coronary arteries become more blocked, pain comes on with relatively little exertion, starting even at rest and taking longer to ease off — this is called crescendo or unstable angina and is serious because, unless treatment is given, one of the coronary arteries may become totally blocked.

Heart attacks

When a coronary artery becomes blocked, the part of the heart muscle supplied by that coronary artery dies — this is more commonly known as a heart attack or myocardial infarction (MI). Heart attacks frequently occur without warning and without the presence of any other obvious symptoms (e.g. angina).
The usual symptoms of MI are severe, persistent, crushing chest pain radiating to the arms, with sweating, nausea, vomiting and breathlessness.
If you suspect you are having a heart attack, call an ambulance, chew an aspirin (this reduces further blood clotting) and rest until the ambulance arrives.
At its worst MI can prove fatal, but even if the patient survives the heart is weakened, unable to pump blood around the body effectively. This condition is known as heart failure, and can cause breathlessness and, sometimes, the accumulation of fluid around the ankles.

What's the risk?

It's high. CHD is the most common cause of death in the UK, accounting for around 117,000 deaths a year and for approximately one in four deaths in men.

There are about 178,000 cases of angina among men every year in the UK.
MI affects six in every thousand men per year.
Although death rates have fallen 4% per year since the 1970s, the death rate in the UK is still high compared with, say, the USA or Australia.
Since the early 1990s the death rate among professional men has been much lower than among unskilled men.

What causes it?

A number of risk factors have been identified. The most important ones are:

Smoking
High blood pressure
High cholesterol levels
Diabetes
Obesity, especially central "apple-shaped obesity" (also known as "big belly obesity")

But the following may also be important:

Lack of exercise
A family history of premature (under 60 years) development of CHD

You should also know that:

Men are at higher risk than women.
Some areas have a higher incidence of, and therefore risk of, CHD — for example, Scotland.
Having a Type A personality (i.e. success-driven, aggressive, ambitious, compulsive and competitive) increases the risk.
Lower social class increases the risk.

How can I prevent it?

Obviously, some of these risk factors cannot be modified — you can't pick your parents! However, first and most importantly don't smoke, and if you do, give it up pronto.

Get your blood pressure checked every five years. It's a quick, simple and painless test that your GP or practice nurse can perform.

Ask your GP for a cholesterol level check if:

You have a family history of high cholesterol levels.
You have a family or personal history of CHD before the age of 60.
You have other risk factors for CHD — see above.
You have signs of high cholesterol, e.g. yellow deposits around the eyes or a white ring around the iris.
If you or a family member has diabetes.

If your cholesterol level is higher than it should be, adjusting what you eat is the first step in getting it down. Your GP will decide if tablets are needed to lower your cholesterol. Essentially, you should avoid fat — so limit:

fry-ups, fish and chips and fatty meat
full-fat milk, cream, full-fat cheese and butter
cakes, pastries, savoury snacks and biscuits

Although taking steps to lower a high cholesterol level is obviously a good idea, it's all too easy to go over the top and become totally obsessed with your diet and latest cholesterol result. Remember that cholesterol is only one risk factor for CHD.

Spend a couple of minutes calculating your Body Mass Index (BMI). Multiply your height (in metres) by itself and divide the answer into your weight (in kilograms) — the resulting number is your BMI:

A healthy weight for your height is 20—25.
Overweight is over 25 and up to 30.
Obese is over 30.

Calculate your BMI

A diet low in fat and high in fibre (roughage) is the best way to try to lose weight at no more than a couple of pounds or so a week.

Drug treatment for obesity.

Ideally, your efforts should be combined with exercise. This instantly conjures up visions of pounding a jogging track getting hot and sweaty and gasping for breath — not so. Brisk walking three times weekly for about 20—30 minutes is enough. If you haven't exercised for some time, or are very overweight, it would be prudent to check first with your GP.

Make sure you don't have diabetes — have your urine checked. If you have diabetes, control it as well as you can.

Should I see a doctor?

If you have been experiencing pain or discomfort across the chest, especially if that pain is similar to the description given in "What are the main symptoms?", you should see your GP without delay. As already mentioned, heart pain is frequently mistaken for indigestion and tests are often needed to rule out, or confirm, CHD. This is not as straightforward as you might think, so don't feel that you've wasted your GP's time even if, after investigation, the pain is attributed to other causes such as chest muscle strain or oesophagitis (inflammation of the gullet).

Your GP will need to question you closely about your symptoms and then he or she will most probably examine you (although the examination is not usually very helpful).

The first investigation he or she will perform is a 12-lead resting ECG (electrocardiogram), which is a painless recording of the heart's electrical activity. The ECG tracing can reveal evidence of a previous heart attack and can sometimes show particular changes which suggest that the patient has CHD. It is important to realise, however, that a normal ECG does not rule out angina or heart disease.

The next stage is an exercise test, which takes place in hospital. With ECG leads attached to your body you'll be asked to walk on a treadmill which will gradually increase in speed, thereby increasing the effort you put in. This might set off the pain you've been experiencing. If typical changes then occur on the ECG, this suggests strongly that your pain is attributable to angina. Unfortunately, a normal exercise test does not necessarily rule out CHD.

Other investigations may be needed if it's impractical to perform an exercise test or if the result is inconclusive — for instance, scanning the heart after exercise during which the patient is given an injection of a minute amount of radioactive material (e.g. thallium).

Sometimes the only way of telling whether the coronary arteries are diseased is to perform a coronary angiogram. This is now a routine test carried out in hospital. A fine catheter is inserted through the groin or arm into the aorta where the coronary arteries arise. Dye is injected through the catheter and down the coronary arteries in turn — X-ray pictures are then taken. Any evidence of CHD should be clearly seen.

A coronary angiogram is also needed if:

a patient with known CHD is being considered for surgery
angina is severe and resistant to treatment
the patient has unstable angina
angina occurs after a heart attack
angina or heart attack occurs in a young (under 50 years of age) patient

What are the main treatments?

Angina

The advice already given about prevention applies.

Angina patients should take a small dose of aspirin every day — usually 75 mg, unless there is aspirin allergy or intolerance.
Acute attacks of angina are treated with glyceryl trinitrate (GTN). This is available as tablets that can be dissolved under the tongue or as an aerosol that is sprayed under the tongue or inside the cheek.

Three main groups of drugs are used in angina:

Ideally, angina patients should be taking beta-blockers (examples are atenolol or bisoprolol), which reduce the heart rate and force of contraction. This has the effect of reducing the amount of oxygen the heart needs when exercising so angina pain is less likely to occur. Some patients, for example asthmatics, should not take these drugs.
Calcium antagonists (examples are nifedipine or amlodipine) work in different ways to reduce the heart's oxygen consumption, thereby improving angina pain.
Long-acting nitrates (examples are Elantan LA or Imdur) (GTN only works for 20 minutes or so) widen coronary arteries and decrease the pressure inside the heart, thus lessening angina pain.

In unstable angina all the drugs above are used in combination — the nitrates are given intravenously, and the patient is bed-rested and given oxygen, sometimes with intravenous blood thinners (usually heparin).

Surgery may be an option if angina pain is resistant to treatment or worsens. Certain types of coronary artery blockage are best treated surgically and an angiogram will show your specialist which treatment is most appropriate for you.

Angioplasty

Angioplasty is a technique of widening an obstructed segment (stenosis) of a coronary artery using a tiny balloon mounted on a catheter, which is introduced into the heart under local anaesthetic by puncturing a blood vessel in the groin.

When the balloon is in the correct position, it's inflated against the obstruction, squashing it and thereby widening the artery at that point. More than one obstruction can be dealt with in the same way. Because complications can occur and the coronary artery can be obstructed totally (a 2—4% risk), angioplasty is usually performed where bypass facilities are also available.

Unfortunately, angioplasted vessels are apt to narrow again (up to a 30% risk) in the six months following the procedure. To prevent this, a tiny metal stent is often inserted, which presses against the sides of the coronary artery to prevent it closing.

Coronary artery bypass grafting

If angioplasty is not possible or is unsuccessful, coronary artery bypass grafting (CABG) under general anaesthetic will then be considered. In CABG, a blood vessel removed from the leg or chest is used to bypass the blockage(s). During surgery the heart is stopped and blood is diverted using a special machine which continues pumping blood to all the vital organs. At the end of the procedure, the heart is restarted.

CABG can be combined with a procedure called endarterectomy where atheroma is stripped away from the artery rather like clearing a blocked pipe.

CABG provides dramatic relief from angina in about 90% of patients, and some (but not all) operations increase life expectancy too. The death rate from surgery is around 1%. Atheroma can of course continue to develop in the coronary arteries and the inserted grafts, and a significant proportion of grafts can block off with blood clots, leading to a return of angina. All in all, though, surgery is usually very successful and leads to a great improvement in the quality of life.

Heart attacks

If myocardial infarction occurs, admission to a coronary care unit (CCU) is the safest policy because serious and potentially fatal irregularities of the heartbeat are liable to occur, especially in the first 48 hours. In a CCU you can expect:

24-hour ECG monitoring
An intravenous cannula will be inserted so that medication can be given to you quickly if needed
Oxygen will be given for several hours and you will be kept in bed
Streptokinase will be given intravenously to dissolve the obstructing clot
You may be given blood thinners to prevent deep vein thrombosis (blood clotting in the deep veins of the legs or pelvis)

After a heart attack the surgical options for angina (as described above) may be used to tackle the underlying CHD.

How can I help myself?

If you have a diagnosis of CHD, there's a great deal you can do to help yourself. All the preventative advice applies:

Don't smoke.
Get your BP checked and if it's raised, treated.
Ensure your cholesterol level is below 5.0 mmol/l by modifying your diet and taking any drugs prescribed to you by your GP.
If your BMI is high, lose weight.
Take up some mildly strenuous exercise, e.g. brisk walking.
Take any prescribed medication regularly.
Get checked for diabetes — and if you have it, make sure it's treated actively.

What's the outlook?

People react in different ways when they find out that they have CHD. Some will adopt a fatalistic attitude of "Oh well, you have to die of something!" Others may become over-anxious, worrying about every twinge in the chest in case it heralds the onset of a heart attack. Many will adopt restrictive diets that they can't possibly maintain, or start heavy exercise programs they drop after a few weeks, despite initial good intentions.

Statistics indicate that, overall, somewhere between 0.5 and 4% of CHD patients die per annum. That is obviously a very small proportion of those affected but it should not be a reason for complacency. The advice you have been given here, coupled with the guidance from your GP, should put you on the right track.