Angina

 

What is angina?

Angina is the medical term for a symptom of chest pain or tightness that is usually felt in the centre of the chest and brought on by certain situations such as exercise, cold weather, emotional stress or a heavy meal. Typically it goes away once the person rests or when the aggravating factor (cold weather or emotional stress) disappears. It indicates that the blood supply to the heart muscle is in some way restricted.

If the pain experienced seems to persist, or is accompanied by shortness of breath or sweating, even when resting, it is important to seek medical advice immediately.

How does it occur?

The muscles of the heart are responsible for the lifelong pumping of blood around the body. The heart is also supplied with food and oxygen by means of delicate blood vessels running around the outside of the heart. These are the coronary arteries. In normal health the supply of blood is sufficient to meet the needs of the heart as it pumps blood to the rest of the body.

If one or more of the arteries becomes narrowed, the blood supply becomes restricted. At times of increased need, such as during exercise or stress, the heart rate and blood pressure rise. This puts a greater demand upon the heart, requiring increased blood flow in the coronary arteries. If the arteries cannot deliver sufficient blood to meet this need, the muscles will lack the necessary oxygen and the patient experiences angina.

 

The most common cause of narrowing of the coronary arteries is the gradual build up of fatty material (called 'atheroma') on the inside of the walls of the artery. This process is called atherosclerosis. It is more likely to occur in certain groups of people such as smokers, diabetics, those with high blood pressure or high levels of cholesterol (a type of fat) in the bloodstream, and people with a close family history of angina or heart attacks at an early age.

As the atheroma builds up inside the blood vessels, they become 'furred up' and therefore allow less blood through. There comes a point where the blood supply to the heart muscle is so restricted that in certain situations of increased need, pain is experienced. This is angina.

In rarer cases angina can be caused by problems with the valves of the heart, severe anaemia, conditions that cause the heart to have an abnormal rhythm or spasm of the coronary arteries. The common factor, however, with all causes of angina, is a reduction in the blood supply to the heart muscle.

What are the symptoms?

Classical angina is recognised by the occurrence of a pain across the centre of the chest. It is commonly described as 'vice-like' or 'crushing' or may resemble indigestion or heartburn.

In a typical case, the pain will move to the left arm and is often accompanied by numbness or 'pins and needles' in the forearm or fingers. The pain may also radiate upwards to the neck, throat or jaws. Some people's angina may alter from the description given above. For instance, in some cases they may feel it as a shoulder or back pain, which comes on with exercise and which goes with rest, but each individual will begin to be able to tell what their own angina feels like.

Angina usually lasts a few minutes and if brought on by exercise, then rest will relieve it. The established angina sufferer will recognise those circumstances that predictably bring on an attack and will learn to avoid them or begin treatment early in anticipation of the symptoms.

 

How is angina diagnosed?

In many cases a doctor can confidently suspect a diagnosis of angina from the description of the symptoms given by the patient alone. However, it is still important to confirm the diagnosis and to establish the cause of the angina and the severity of the narrowing of the coronary arteries. This is done by organising one or more of the tests described below:

Electrocardiogram (ECG):

This records the heart's electrical activity via a number of recording pads being placed onto the patient's chest and limbs. It is a simple, painless test that can be performed in the GP's surgery but can be normal in up to 50 per cent of cases of angina, so it is not a particularly accurate test for angina but is still frequently done since it is a useful baseline test for anyone suffering with chest pain and can help to exclude a heart attack.

An exercise ECG

An exercise ECG ('exercise or treadmill test') is an ECG, which is performed whilst the patient gradually increases the amount of exercise they do on a running machine in a carefully controlled way. This is a more accurate way of showing whether or not the heart muscle is starved of oxygen during exercise.

Coronary angiogram

This is another very useful test in which a small tube (a catheter) is threaded from an artery in the arm or leg into the coronary arteries. A dye is injected and an x-ray will show up the precise site of any narrowing of the arteries. This will enable the doctor to assess the most appropriate treatment.

Technetium or thallium scans

In some cases these special scans of the heart are used to detect restriction of the blood supply to the heart. They involve the injection of radioactive markers (either technetium or thallium) into the bloodstream, which are then tracked using a special scan. Areas of poor perfusion of heart muscle (where very little blood is reaching the muscle) can be seen.

Sometimes these scans are done whilst the patient is exercising on a treadmill.

Other tests

Blood tests

These may be carried out to exclude anaemia and to check for diabetes and high cholesterol levels and if the doctors want to exclude a recent heart attack a blood test called a Troponin level will be done. This chemical increases in the blood it heart muscle damage has occurred.

An ultrasound scan of the heart (called an echocardiogram)

This is frequently done to look for valve or other problems that may be contributing towards the angina.

 

What treatment is available?

Treatment for angina falls into three main groups: measures to slow down the narrowing of the arteries, drugs to treat the symptoms of angina, and surgical treatments.

Measures to slow down the coronary artery narrowing

Treatment for angina falls into three main groups: measures to slow down the narrowing of the arteries, drugs to treat the symptoms of angina, and surgical treatments.

Measures to slow down the coronary artery narrowing

Since most cases of angina are as a result of 'furring up' of the arteries to the heart muscle, it makes sense to do as much as possible to slow this process down. This means reducing to a minimum those things that are known to contribute to the build up of atheroma in the artery and some of these are listed below:

Stopping smoking

Smoking doubles the risk of heart disease and is the single most important thing that a patient with angina can do for themselves to slow down the onset or worsening of angina. On a more positive note, it has been found that a year after someone has stopped smoking, their increased risk of heart disease is halved and after 10 years of not smoking, their chances of heart disease become similar to that of someone who has never smoked.

Doing regular exercise

This must obviously be done with help and advice from the GP or specialist, since obviously, strenuous exercise can be dangerous. However, in most cases regular moderate exercise (which may just mean going for a regular walk each day) can help to promote the blood supply to the heart muscles.

Other lifestyle measures

Avoidance of obesity by eating a healthy diet and not indulging in excessive alcohol intake are helpful in the treatment of angina.

Treating high blood pressure

People with untreated high blood pressure are more likely to develop angina since this contributes to the 'furring up' process mentioned before and puts a greater strain on the heart which has maintain the increased blood pressure. Treating high blood pressure, usually with medication, is therefore beneficial.

Reducing raised levels of cholesterol and triglycerides in the blood

Cholesterol and triglycerides are both types of fat which appear in the blood and which are essential for the normal functioning of the body. However, if the levels of these substances become high, they can contribute significantly to the build up of atheroma in the arteries. In these cases, reducing the levels of these fats in the blood, either by dieting or with the help of cholesterol-lowering drugs, such as a group of drugs called statins, results in a slowing down of the narrowing process in the arteries.

Currently the recommended target for cholesterol level in someone with ischaemic heart disease (angina or past history or heart attack) is total cholesterol of less than 4.

Good control of blood sugar and blood pressure in those angina sufferers with diabetes

The combination of high blood pressure and poorly controlled diabetes is not a good one for the arteries of the body, since this frequently results in the build up of atheroma in the arteries as described above. Therefore, controlling the blood sugar and blood pressure levels in diabetics with a combination of diet and if necessary, medication, is especially important in the treatment and prevention of angina.

Taking aspirin or similar blood thinning medication

Although this involves medication, the taking of aspirin falls into the category of a prophylactic measure. The action of aspirin is to slow down or reverse the narrowing of the arteries to the heart, since by thinning the blood, aspirin has been found to reduce the 'furring up' process within the arteries. Studies have shown that the taking of 75 mg of aspirin a day produced a 13 per cent reduction in the risk of death from heart disease in the subsequent two years, in people with ischaemic heart disease (narrowing of the arteries to the heart).

There are some people who are unable to take aspirin for one reason or another (such as a past history of stomach ulcers or severe allergy to aspirin). For those people, an alternative called clopidogrel is sometimes suitable, as it has been found to have fewer significant side effects. Clopidogrel is also often prescribed for a while after someone has had an angioplasty and stent procedure (see below).

 

Drugs used to treat the symptoms of angina

In principle, the aims of treatment are either to reduce the heart's need for oxygen or to increase its blood supply. In many cases angina can be treated with tablets (either one type or a combination), whilst in the remainder, some form of surgery is needed when drugs have been unsuccessful.

The main groups of medication used to treat angina are set out below.

Betablockers

These work by relaxing and slowing down the heart so that the work demand (and the need for oxygen) is reduced. They also have the advantage that they tend to lower blood pressure. Examples of beta-blockers include atenolol, metoprolol and bisoprolol.

Short-acting Nitrate

these works by temporarily widening the coronary arteries, thus allowing more blood to flow to the heart muscle and also by dilating the blood vessels of the body, which makes it easier for the heart to pump blood around the body. The types of treatment may be in an immediate form of a tablet or spray, both of which are applied under the tongue where they are absorbed within a few minutes. The tablet form of this medication only has a shelf life of 8 weeks and therefore needs to be replaced after this time so the spray form tends to be more commonly recommended. They are mainly used for the temporary relief of angina.

Long acting nitrates (such as isosorbide mononitrate)

These mainly act in the same way as the short acting nitrates mentioned above, but they have a longer lasting action and are therefore used to try to prevent angina from occurring in the first place. They are usually given in the form of a tablet but can also be administered as a patch, which releases the drug slowly into the bloodstream through the skin. Examples include a drug called Isosorbide Mononitrate.

Calcium channel blockers

These work by blocking the movement of calcium salt in the heart muscle, and like betablockers, reduce the work demand on the heart. Examples of this group of drugs include Diltiazem, Amlodipine, Nifedipine, and Verapamil.

Potassium channel activators (such as nicorandil)

This drug acts by opening up the arteries and veins of the heart in a very sophisticated way. Some studies have also shown it to have some effect in preventing heart attacks.

Angiotensin-converting enzyme (ACE) inhibitors

These drugs, which include Ramipril and Enalapril, are often prescribed particularly for angina sufferers who also need treatment for high blood pressure or heart failure because they have been found to be effective in reducing strain on the heart muscles.

Ivabradine

A relatively new anti-anginal drug it works by reducing the heart rate and tends to be used in people who are unable to take beta-blockers.

 

Surgical treatments

The principal aim here is to improve the obstructed coronary circulation in one of the following two ways:

Coronary angioplasty

Here a fine tube or catheter with a balloon in its tip is introduced into the artery in the arm or groin and is threaded through the blood vessels and into the coronary artery. The tip is sited at the narrowest part and inflated. This compresses the built up material against the wall and so widens the artery. In most cases a short length of tubing called a 'stent' is placed at the same time into the area where the narrowing existed, to prevent the artery from becoming narrow in that area again.

Unfortunately, even if a stent is used, the artery can narrow once more (re-stenosis), in which case the procedure may have to be repeated or, in about 30 per cent of cases, the individual has to go on to have a coronary artery bypass operation.

Coronary artery bypass graft (CABG)

A CABG is a major operation but these days it is quite a common one; 25,000 bypass operations are performed per year in the UK. The patient's chest is opened via a cut down the middle of the breastbone, extending into the upper part of the abdomen. If a vein from the leg is to be used to bypass the narrowed section of coronary artery, a second surgeon will be removing this vein from the leg whilst the first surgeon is at work opening the chest. A heart-lung machine is then used to take over the work of the heart and lungs so that the heart can be stopped whilst the surgeon operates on it.

The surgeon then uses the vein removed from the leg, or an artery called the internal mammary artery from inside the chest wall, to form new coronary arteries where they are needed to bypass the furred up ones. The patient is then taken off the heart-lung machine and blood is then able to flow through the newly-formed arteries to supply the parts of the heart which were previously starved of blood. The operation usually lasts between three and five hours.

After the operation, the patient is taken to the intensive care unit (ICU) until their condition has stabilised enough to allow them back to the ward.

A day or two after the operation, the patient is usually taken from ICU to a normal ward and is usually discharged home, a week or so later. An out-patient follow-up appointment will usually be arranged for them, but the timing of this varies between hospitals. They will be advised by the consultant about resuming activities, but normally it is suggested that they gradually increase what they do over the next three months, after which all normal activities should resume. The timing of return to work will vary from one person to another, but on average someone will need between two to three months off work following a CABG.

Driving is not allowed for one month after a CABG but it may be sensible to leave it until about six weeks before driving again, depending on how the individual feels. One of the most troublesome symptoms afterwards tends to be pain at the site where the chest was opened in the middle of the breastbone, but this will gradually subside.

 

Living with angina

Naturally, as an angina sufferer, one will wish to live as normal a life as possible. This may mean making modifications to lifestyle and cutting down on work commitments in order to reduce those factors, such as physical exertion and stress, which can provoke an attack of angina.

A gradual increase in exercise taken on a regular basis such as walking, swimming, golf and cycling is excellent for the heart and circulation.

Driving is permitted but the DVLC at Swansea should be informed if angina is still active, and driving is necessary or desirable.

Sexual activity is perfectly safe provided that it does not provoke an attack of pain. A tablet of glyceryl trinitrate taken prior to intercourse can be helpful and reassuring.

How can the risk of angina be minimised?

The most important measures aim at reducing the chance of developing atheroma on the walls of the arteries. The relevant protective measures are to:

  • stop smoking
  • avoid obesity
  • keep the cholesterol level as low as possible by healthy eating - your GP will advise about how to achieve this and what level of cholesterol should be achieved
  • take the medication as prescribed by the doctor
  • report any worsening of the angina symptoms. If the symptoms last for more than 15 minutes, or are associated with other features such as sweating, sickness or feeling faint, seek emergency help immediately.
 

Where can I get further information?

Apart from contacting your GP, the following organisations may be of further help:

British Heart Foundation
Greater London House
180 Hampstead Road
London
NW1 7AW
Telephone: 020 7554 0000
Website: www.bhf.org.uk

Heart UK
North Road
Maidenhead
Berkshire
SL6 1PE
Telephone: 01628 628638
Email: ask@heartuk.org.uk
Website: www.heartuk.org.uk

Heartline Association
Community Link
Surrey Heath House
Knoll Road
Camberley
Surrey
GU15 3HH
Telephone: 01276 707636
Email: heartline@easynet.co.uk
Website: www.heartline.org.uk