Stroke care must improve

Medical Matters:   The serious and life-threatening stroke suffered by Israeli Prime Minister Ariel Sharon earlier this month has focused attention on the treatment of strokes.

In particular, it has raised questions about the role of anticoagulant and clot-busting drugs, as well as the place of surgery and medically induced coma in stroke treatment.

Sharon, who remains seriously disabled and semi-conscious, was admitted to hospital on January 4th following a massive stroke. In December, he had experienced a mini-stroke or transient ischaemic attack (TIA) following which he was treated with drugs to prevent a recurrence.

While we do not have all the details of Sharon's treatment, especially the exact medication he had been prescribed, we do know that following the second, larger stroke, he was operated on by neurosurgeons for nine hours in an attempt to drain the haemorrhage that had accumulated in his brain.

And he was also placed in a medically-induced coma for about 48 hours after the second stroke.

It is almost certain that Sharon had two different types of stroke.

The first, milder one was what we call an ischaemic stroke. Some 80 per cent of strokes are of this type, in which the blood supply to a part of the brain is cut off by a clot.

The brain is starved of oxygen by the clot that forms either in an artery in the brain or breaks off from a larger artery, such as the carotid in the neck, and then travels to lodge in the brain.

The second, more serious, stroke suffered by Sharon is termed a haemorrhagic stroke. Between 15 and 20 per cent of strokes are of this type, in which blood leaks from an artery into the brain.

The treatment of ischaemic and haemorrhagic stroke is very different. It is crucial to carry out a CT or an MRI scan to distinguish between the two types. Giving the clot-busting drug, tissue plasminogen activator (TPA) in the early stages of an ischaemic stroke can rapidly reverse any damage caused.

However, giving the same drug to someone with a haemorrhagic stroke is like pouring petrol on a fire and will make the bleeding much worse. TPA must be given within the first three hours of symptoms and requires the input of senior staff in a specialised stroke unit.

Because there is a 44 per cent risk of having either a heart attack or a stroke within 10 years following a minor ischaemic stroke or TIA, it is important to consider measures to prevent a further cardiovascular event.

The first line of treatment is anti-platelet therapy in the form of aspirin. Research shows that for every 1,000 people who have an ischaemic stroke or a TIA, treatment to prevent platelets sticking together (thereby reducing the risk of a clot) taken for three years prevents 25 non-fatal strokes, six non-fatal heart attacks and 15 deaths.

In addition, good control of high blood pressure and diabetes and the use of cholesterol-lowering treatment all help to lower the risk of a further stroke.

Anticoagulants, in the form of warfarin, are confined to a specific group of patients who have a heart rhythm disturbance called atrial fibrillation.

In this condition, clots are flicked off by the heart to the brain. Using warfarin, in these patients significantly reduces the risk of a stroke. Warfarin, however, increases the risk of a fatal bleed into the brain, and so its use cannot be justified in people with a normal heart rhythm.

But back to Sharon. His doctors have said they prescribed anticoagulants after his first stroke.

We also know that he was operated on in an attempt to clear the haemorrhage in his brain. While there is some evidence that draining a clot or reducing brain swelling can help, it is difficult to choose the patients that will benefit.

It has been suggested that haemorrhages in the outer lobes of the brain respond best to surgery and this is the basis of the more radical approach taken in countries like Israel and the United States. A much more conservative approach to stroke surgery is taken on these islands.

Sharon was also placed in a medically-induced coma using barbiturate drugs. This treatment is controversial with little evidence to support its effectiveness.

The idea is to reduce the production of toxins that kill brain cells but the risk is that the patient may emerge from the coma either permanently dependent on life-support or in a persistent vegetative state.

All of which shows just how complex and even controversial aspects of stroke management have become.

It emphasises the importance of having dedicated stroke units in our major hospitals so that a person with an acute stroke is treated in the same way as a patient with a heart attack .

As one stroke specialist put it: "We badly need to upgrade stroke care. A national policy on stroke is sorely needed."

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