Fending off riskof stroke

Medical matters:I have been consulted by a lot more people looking for advice on how to prevent heart disease than I ever have by patients worried about a future stroke.

This is despite research showing that people dread having a stroke far more than a heart attack. And with good reason: just half of acute stroke survivors make a complete recovery, while 90 per cent of heart attack survivors return to work and resume normal lives.

Why do people focus more on preventing heart attacks? Is it because they think that the same prevention steps will also protect their brain? Or is it because strokes develop for a variety of reasons, making it more difficult to explain prevention and treatment?

Perhaps younger people regard stroke as something that happens to older people and therefore do not consider themselves at risk. Stroke can occur at any age; half of all strokes occur in people over 70.

Some risk factors are common to both diseases. Smoking, high blood pressure and elevated cholesterol can cause stroke and heart disease. But factors such as narrowing of the neck arteries and the abnormal heart rhythm called atrial fibrillation primarily threaten the brain and require different and sometimes complex treatment.

Almost 10,000 people develop a stroke in the Republic each year. Some 30 per cent of these die within one year of having a stroke. And there are about 30,000 people who are stroke survivors, many of whom have a significant disability that affects their independence, such as speech problems or a weakness on one side of the body (hemiplegia).

There is nothing we can do for certain stroke risk factors. Your age, your ethnicity and having a family history of stroke cannot be changed. But many risk factors for stroke can be modified and your doctor can calculate your risk of developing cardiovascular disease in the next 10 years using European Society of Cardiology (ESC) guidelines.

The single biggest risk factor for stroke is high blood pressure. Hypertension triggers up to 40 per cent of both types of stroke: ischaemic stroke caused by blockages in blood vessels supplying the brain; and the less common haemorrhagic stroke which is caused by a ruptured blood vessel within the brain. If your blood pressure is consistently raised then try losing excess weight, exercise moderately and cut back on salt.

For pressures greater than 140/90, that don't respond to lifestyle changes, talk to your doctor about the need for antihypertensive medication.

If you are a smoker, then your lifetime risk of developing a stroke is raised by 50 per cent. The good news is that within five years of quitting, a person's risk of stroke returns to that of the general population.

The next time you visit your doctor or practice nurse, ask them to listen to your heart beat and feel your pulse. This is the simplest way to check for atrial fibrillation which, if left untreated, may cause blood clots to form and be flicked off to the brain, thereby causing a stroke.

Apart from controlling the heart rate, a key aspect of preventing arrhythmia-induced stroke is to take a blood-thinning drug such as warfarin, which reduces the risk of stroke by 70 per cent. But not everyone is suited to warfarin therapy; you may be offered aspirin as an alternative.

Ask the doctor to listen with his stethoscope to the blood flowing through the carotid arteries at either side of the neck. A blockage makes a distinctive sound called a bruit; an ultrasound test will confirm the extent of the blockage and you may be offered a surgical procedure - a carotid endarterectomy - to clear it.

While the impact of statins (the lipid-lowering group of drugs) in preventing stroke is far less marked than their benefit in preventing heart disease, they may have a role to play in reducing inflammation in blood vessels. But there is little evidence that using statins in people who are not at high risk helps prevent strokes.

And what about diet? A recent paper in the Lancet suggested that taking folic acid could reduce the risk of stroke by 18 per cent. Folic acid reduces the level of the amino acid homosysteine in the blood. High levels of homosysteine have been linked to atherosclerosis, the furring up of arteries by plaque.

Although further research is needed before folic acid supplementation could be justified for stroke prevention, the recent recommendation to fortify bread with folic acid (to help prevent neural tube defects in babies) may in time reduce mortality from stroke.

Last year, a large study showed that eating more than five portions of fruit and vegetables a day significantly reduces your risk of stroke. Compared with people taking fewer than three servings a day, those eating more than five portions of fruit and vegetables had a 26 per cent reduction in the incidence of stroke.

For those who do develop a stroke, the good news is that advances in medical technology, drugs and rehabilitation have transformed acute stroke care.

Specialised units can prevent death and disability in one-fifth of stroke victims. Dedicated stroke units are not available on an equitable basis throughout the State, but that is an issue for another column.

Dr Houston is pleased to hear from readers but regrets he cannot answer individual queries.