Tiny umbrella that can prevent a stroke

by MARTYN HALLE, Daily Mail

Patients at risk of life threatening strokes are being treated with a new 'clot-catching' device inserted into their hearts. For years the standard treatment has been to use the blood-thinning drug warfarin to prevent clots.

But this can have side-effects and actually cause the reverse of clotting - uncontrolled bleeding.

The aim of the new device - pioneered by an American company - is to stop clots that form in the heart from travelling along blood vessels into the brain where they can block the blood supply and cause a stroke.

So far, more than 50 patients have had the implant fitted - mostly in Europe - and results suggest it is safe and effective. More trials will start soon at British hospitals.

In the new procedure, doctors attach the acorn-shaped gadget to block off part of the heart where most clots originate, sealing off the danger route to the brain.

The device is a collapsible metal cage, covered with a membrane, and when in place it pops open rather like a tiny umbrella. Its full name is percutaneous left atrial appendage transcatheter occlusion - PLAATO for short.

It has been designed to treat those with a heartbeat disorder known as atrial fibrillation (AF). There are about 200,000 sufferers in Britain, with 20,000 new cases diagnosed each year.

Studies have shown that more than 90 per cent of AF-related strokes result from a blood clot that forms in the left atrial appendage, a small, thumbshaped pouch in the heart's left upper chamber. People with AF are five times more likely to suffer a stroke than those with a normal heart rhythm.

Atrial fibrillation causes a marked decrease in the pumping action of the upper chambers of the heart, which results in sluggish blood flow.

Because the pumping function isn't working properly, the blood is not completely emptied from the heart's chambers, causing it to pool and sometimes clot.

In time, these clots can not only break loose to block arteries to the brain, but can also block arteries to limbs or internal organs with dire consequences.

Dr Peter Block, of Harvard Medical School, who has led research into the device, says: 'There were no adverse events and there seems to be a reduction in stroke. It just catches the clot.'

Atrial fibrillation affects many more people than are diagnosed but in some the condition is only mild and is unlikely to require treatment.

Most of those diagnosed are over 50 and have felt flutters where their heartbeat has changed. Or they have had symptoms of breathlessness. For years, doctors have used warfarin to control clots but the drug is difficult to manage and many patients are unable to tolerate it.

Some doctors are reluctant to treat AF with warfarin because of the risk of elderly patients falling and having an accident, which could cause them to haemorrhage - particularly from a head injury - due to thinner blood.

The new device, effectively a plug, is fitted to the end of a catheter and fed through the body until it reaches the left atrial appendage. It is then expanded and tugged gently so that tiny hooks embed themselves in the surrounding tissue - sealing off the exit.

Dr Block says one beauty of the device is that it can be withdrawn if it does not fit properly.

'It just collapses and we pull it out. We are optimistic this is a good treatment for those patients who are not good candidates for anti-coagulation (warfarin).'

'The left atrial appendage has no purpose; no one needs it,' says Dr Horst Sievert, who carried out a trial on 15 German patients. 'It can be blocked with no disadvantage to the patient.'

Dr Tony Rudd, a stroke specialist at St Thomas's Hospital, London, says the device has great potential.

'At the moment our main treatment is the use of anti-coagulation therapy but this looks to have potential as a genuine alternative to drugs.

'AF affects a large number of people and if we can control it through a device and not drugs, that might be preferable for many patients, particularly those most at risk of problems with warfarin.'