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Friday, 14 June, 2002, 15:02 GMT 16:02 UK
Drugs protect brain in heart ops
Thousands of bypass operations take place each year
Thousands of bypass operations take place each year
Patients undergoing heart bypass operations should be given beta-blockers to prevent brain damage, say doctors.

Researchers from Duke University Medical Center, Durham, North Carolina, US say if given before or during coronary artery bypass surgery, the heart drugs offer a significant degree of protection to the brain.

They now say all bypass patients should receive the drugs during their operations. Now, only around two-thirds receive them in the US.

The researchers claim this is the first study to look at the drugs' effect on the brain, but beta-blockers have previously been shown to help improve how heart patients fared, and benefit patients undergoing surgery.

Beta blockers should be given to all patients who can receive them

Professor John Pepper, British Cardiac Society
They examined data for over 2,500 patients who had undergone bypass surgery at the centre over a three year period to see how many had experienced strokes, comas, transient ischemic attacks ('mini-strokes') or encephalopathy.

Only 3.9% of patients given beta-blockers suffered any of these neurological problems, compared to 8.2% of those not on the drugs.

And only 1.9% of those taking the drugs suffered a stroke or coma, compared to 4.3% percent for those who did not.

The benefits of beta-blockers were evident, even when researchers took risk factors such as how ill patients were, their age and whether they had diabetes into account.

'Fight or flight' hormones

Beta blockers have been used over the last 30 years to treat high blood pressure, chest pain and heart irregularities.

They act by stopping the so-called 'fight-or-flight' hormones epinephrine and norepinephrine working by reducing the heart rate and blood pressure.

The study was not designed to show why beta blockers protect the brain.

But the research team suggest it could be that they act to control atrial fibrillation, an irregular heartbeat implicated as a risk factor for stroke and sudden heart attack.

Atrial fibrillation was reduced amongst patients in the study, but the researchers say this could not fully explain the lower risk of complications in patients taking the drugs.

Beta blockers could also reduce stress in patients during surgery.

When a person is stressed, large amounts of epinephrine and norepinephrine are produced, which are neutralised by the drugs, helping to maintain a more normal blood flow to the brain.

They could also help stabilise blood clotting after surgery, the researchers suggest.

Many patients will be taking beta blocker pills before the operation.


Dr Mark Newman, who led the study, said all bypass patients, except for those whose heart is pumping at less than 20% of its full potential, should be given beta blockers intravenously during surgery, so that optimum protective levels could be maintained.

He said: "Data is rapidly accumulating that every patient undergoing bypass surgery -- with a few exceptions -- should be given beta-blockers for bypass surgery.

"The bottom line is that bypass surgery is a very safe procedure, and now we are refining our processes and procedures to improve a patient's quality of life in order to maximize the health benefits."

In the UK, around 35,000 bypass operations take place in both the NHS and private sectors.

John Pepper, professor of cardiac surgery at Imperial College, and a member of the council of the British Cardiac Society, told BBC News Online: "There are many benefits of beta blockers in surgery.

"Clearly this new information about reducing the incidence of brain damage is very important.

"Beta blockers should be given to all patients who can receive them - they are not suitable for patients with asthma or chronic bronchitis."

A spokesperson for the Stroke Association said: "Stroke can be a complication of many types of surgery including heart surgery.

"The Stroke Association welcomes any research which may help reduce the risk of stroke and therefore we look forward to learning more about this particular research with interest."

The research is published in the Journal of Cardiothoracic and Vascular Anesthesia.

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