Strokes - recent promising advances in treatment

Dr J. B. Peiris and Dr Natasha Peiris

HEALTH: Until recently, Western treatment had little to offer for a patient struck down by a paralytic stroke. There is treatment now available for both types of stroke ischaemic and haemorrhagic - clot busters for the former and clot promoter for the latter.

Admission to a centre with CT or MRI facilities within three hours of the stroke is essential for the new forms of treatment, which are currently expensive but cost effective. It has become imperative for patients and family to recognise stroke symptoms and warnings early, for these new forms of treatment to be effective.

What is a stroke or brain attack?

A stroke occurs when blood flow to the brain is interrupted by a blocked or burst blood vessel. When there is a blockage of the blood vessels to the brain it is called an 'ischaemic stroke.'

When a blood vessel ruptures or bursts it causes a 'haemorrhagic stroke.' Thus there are two varieties of stroke which require almost diametrically opposite forms of treatment.

An ischaemic stroke is caused by a thrombus or embolus. A thrombus is the development of blood clot in a vessel wall over fatty deposit.

An Embolus is a travelling particle too large to pass through a small vessel. A haemorrhagic stroke occurs when a weakened blood vessel ruptures.

The rupture may be of an aneurysm (ballooning of a weakened region of blood vessel) or an arterio-venous malformation -AVM- which is a cluster of abnormal blood vessels.

How are strokes treated?

a) Ischaemic- to minimize the clot

* clot busters - e.g. rt-PA or recombinant tissue plasminogen activator

* anticoagulants - warfarin, aspirin

* carotid endarterectomy

* angioplasty/stents

Management of ischaemic stroke Seize the 3-6 hour window of opportunity

Preferably after one hour to exclude TIA

Immediate plain CT head

CT - should show early or no signs of infarction and no haemorrhage.

rtPA 1.1.mg/Kg IV. 10 per cent as bolus in one minute.

- Block buster

Vigorous scientific investigation has demonstrated that intravenous administration of rtPA is an effective interventional therapy for impending ischemic stroke.

The rate of neurological recovery is modest, the risk of intracerebral hemorrhage is low, and mortality is not increased following thrombolytic therapy with rtPA. Not all patients with symptoms of ischemic stroke can be treated with rtPA.

In order to minimise the risk of treatment associated intracerebral hemorrhage, patients must meet strict clinical and radiological criteria before receiving rtPA. Development of other acute interventional therapies in the future may augment the benefits of this medication.

The block buster drug is usually not given for rapidly improving or minor stroke, those with a seizure at onset, history of bleeding from any site, a systolic BP >185 or diastolic BP >110, Platelet count less than 100,000, Blood glucose under 50mg/dl or over 400mg/dl.

Aspirin is and anticoagulants are used to prevent clots from forming or propagating, while angioplasty and stenting of cerebral blood vessels are currently being assessed.

Management of haemorrhagic stroke or brain haemorrhage

Intracerebral haemorrhage (ICH) accounts for about 20-30 per cent of strokes. The onset and progress is often more rapid and outcome poorer.

b) Haemorrhagic - to enhance the clot

* Surgery

* Medical treatment

* Endovascular - coils

Surgery for brain haemorrhage

No overall benefit was shown in a large trial of 1033 patients of whom about half received early surgery and other half were treated conservatively(STICH trial). Some improvement could be expected from surgery in patients who have a large superficial clot with rapid clinical deterioration of the condition.

Early treatment which prevents growth of the clot is needed to minimise the damage. Search for a drug which stops clotting and prevents enlargement of the clot has finally being fruitful.

New drug to enhance clotting

ICH was considered to stop quickly as a result of clotting but now scanning has shown growth of the clot in the first 3-6 hours. Early clot removal did not appear to be beneficial and the search was on for a clotting agent. Recombinant Factor VII has been used to control bleeding in trauma and its value to control ICH has recently being assessed.

In a recent trial of 400 patients with ICH, rFVIIa given within four hours after onset limited the growth of the haematoma, reduced mortality, improved functional outcome at 90 days with a small increase in adverse events due to clotting elsewhere.

The use of Novo seven in other situations of bleeding like trauma, gastro-intestinal and pregnancy is currently being assessed.

With the availability of the new drugs - rtPA for ischaemic stroke and rFVIIa for cerebral haemorrhage, it is becoming increasingly important for patients, relations and friends to recognise early, the premonitory and early symptoms of stroke.

Warning signs of a stroke

They are: Sudden weakness or numbness of the face, arm or leg, especially on one side of the body.

* Sudden confusion, trouble speaking or understanding.

* Sudden trouble seeing in one or both eyes

* Sudden severe headaches with no known cause

* Sudden trouble walking, dizziness loss of balance or coordination

Transient ischemic attacks

TIAs are 'warning strokes' that can happen before a major stroke. They occur when blood flow through a Brain artery is blocked or reduced for a short time.

TIA symptoms are temporary but similar to those of a stroke.

A person who has a TIA is 10 times more likely to have a stroke

Stroke risk factors that can be treated

It is still best to prevent a stroke than attempt to treat it. The risk factors that can be altered are:

* High blood pressure (hypertension)

* Diabetes

* Transient ischaemic attacks

* Elevated blood cholesterol/ lipids

* Cigarette smoking

* Obesity and lack of exercise

* Heart disease

* Alcohol abuse

* High fat and high salt diet

It can be concluded that Western or allopathic has now more to offer a patient with a stroke than mere control of risk factors, supportive therapy and rehabilitation.