Higher stroke and heart attack risk linked to faulty gene

Researchers have identified a gene that may put people at greater risk of strokes and heart attacks.

Higher stroke and heart attack risk linked to faulty gene Published in PLOS ONE The PlA1/A2 Polymorphism of Glycoprotein IIIa as a Risk Factor for Myocardial Infarction: A Meta-Analysis they say the gene fault may encourage the formation of blood clots – the ultimate cause of most heart attacks and strokes.

Scientists hope gene tests may help doctors one day to pinpoint individuals more likely to suffer these conditions, but experts say lifestyle factors such as smoking and exercise have the greatest influence on risk.

Around one in 10 people in the Caucasian population carries this variation of the gene, named PIA2.

And researchers from King’s College London reviewed more than 80 studies involving about 50,000 people – the largest analysis of this genetic fault to date.

They found individuals with PIA2 were more likely to have a stroke – caused by a blood clot blocking blood supply to the brain – than those without the gene.

Scientists calculate the gene increases a person’s risk of having a stroke by 10-15%.

But how significant this increase is depends on an individual’s baseline risk – influenced by factors such as smoking, diet, weight and exercise, the scientists say.

For people with two copies of the gene the risk rises by up to 70% from this baseline.

In a second study published in the same journal, the scientists show PIA2 is also linked to an increased risk of heart attacks in people under 45.

More research is needed to see whether this holds true for the whole population, they say.

About 150,000 people have a stroke in the UK each year and more than 100,000 heart attacks are recorded annually.

Both thrombotic strokes (the most common kind) and heart attacks are caused by blockage of blood vessels in the heart and brain – ultimately through the formation of clots.

The faulty gene appears to affect a protein called glycoprotein IIIa – present on platelets, natural clotting cells in the blood.

Platelets help trigger the formation of clots to stop bleeding after injury. But scientists say carrying the gene may render them overactive.  They caution that overall the genes play a smaller role in risk than more established factors, such as high blood pressure and obesity.

But developing a genetic test could help predict people at highest risk, allowing doctors to suggest more potent medication or lifestyle changes, they say.

Prof Albert Ferro, of King’s College London, who led the research said: “We would now need to validate this test and see how useful it is in the clinical world.

Leonardo da Vinci still teaching us about the heart

After Leonardo da Vinci dissected the heart of a man he produced the first known description of coronary artery disease.

Leonardo da Vinci still teaching us about the heartMore than 500 years later, coronary artery disease is one of the most common causes of death in the western world.

“He had a great mind, and he was willing to really look and see,” says Mr Francis Wells, a consultant cardiothoracic surgeon at Papworth Hospital in Cambridge, who has spent years studying Leonardo da Vinci’s anatomical drawings, which form part of the Royal Collection in Windsor.

His diagrams and sketches of the skull, skeleton, muscles and major organs fill countless notebooks while his theories on how they function fill many more pages.

But it was the heart that appeared to particularly fire his interest, from 1507 onwards, when he had reached his 50s.

In those drawings, he used his knowledge of fluids, weights, levers and engineering to try to understand how the heart functions. He also looked closely at the actions of the heart valves and the flow of blood through them.

Mr Wells’ book, ‘The Heart of Leonardo’, explores the artist’s drawings and writings on the organ, and he says his insights are “quite astonishing. The more we look, the more right we realise he was.”

Many of Leonardo’s conclusions, such as the description of how the arterial valves close and open – letting blood flow around the heart – holds true today, but is not widely known.

“Even cardiologists get this wrong now,” Mr Wells says. “Only with the use of MRI technology has knowledge of this subject been revisited.”

Many of Leonardo’s drawings were based on studies of hearts from ox and pigs. It was only later in life that he had access to human organs, and these dissections had to be carried out quickly in winter before the body began to degrade.

Contemporary dissections of the heart show he was correct on many aspects of its functioning. For example, he showed that the heart is a muscle and that it does not warm the blood.

He found that the heart had four chambers and it connected the pulse in the wrist with the contraction of the left ventricle.  He worked out that currents in the blood flow, created in the main aorta artery, help heart valves to close. And he suggested that arteries create a health risk if they fur up over a lifetime.

Mr Wells also believes that Leonardo realised that the blood was in a circulation system and may have influenced William Harvey’s discovery in 1616 that blood was pumped around the body by the heart.

Yet none of Leonardo’s theories or drawing were ever published during his lifetime. In fact, his notes were not rediscovered until the late 18th century – more than 250 years after his death.

With hindsight they may have had the potential to revolutionise surgery.

In the 16th century, for example, there was no treatment for cardiac disease, or many other diseases, and surgeons occupied a low status in society.

If people survived surgery, it was more by luck than judgement. Heart surgery has transformed in the past century, but Leonardo’s insights could have made a huge difference if they had been made public earlier.

Even now, however, there is common consensus that we have barely scratched the surface of what we know about the heart.

According to Mr Wells, Leonardo’s legacy is that we should follow the Renaissance Man’s example and continue to challenge, question and enquire rather than listen to accepted wisdom.