March 2012

Breakthrough Findings from Irish Research Team Predicts Risk of Recurrent Stroke

Wed, 28 March 12 09:00

Prof Peter KellyThis discovery means that patients who are at very high risk of a second - and often far more debilitating stroke - might be identified through diagnostic imaging tests and receive intensive treatment, such as surgery, to reduce or remove excess carotid plaque.

Stroke kills more than 2,000 people a year in Ireland – a higher death toll than from breast cancer, prostate cancer and bowel cancer combined.  Many strokes are due to the accumulation of fat and fibrous tissue, also known as plaque, in the walls of carotid arteries, which supply blood to the neck and head. Currently, one in four patients who have a  Transient Ischemic Attack (mini-stroke) due to carotid plaque will experience a second stroke within 90 days, even when treated in line with best practice guidelines.

The findings are based on a study involving 60 patients, all of whom had suffered a mini-stroke. A diagnostic imaging test to measure plaque inflammation was carried out on each patient within 14 days of the initial mini-stroke. Follow-up measurements and analysis were carried out for a period of 90 days. Of the 60 patients who participated, 13 had a recurrent stroke. The research team found that there was a very significant association between plaque inflammation and the 13 patients who had a recurrent stroke.

Professor Peter Kelly, Principal Investigator on the project, Associate Professor of Neurology at UCD and Consultant Neurologist at the Mater University Hospital said the findings could have important implications for the health and prospects of patients who present following a minor stroke.

“At the moment 20 out of every 100 patients who suffer a mini-stroke will have another stroke within 90 days. The risk is frontloaded in the week immediately following the mini-stroke, and a recurrence is usually far more profound and debilitating. This research describes a way to determine those patients who are most at risk by measuring the level of plaque inflammation in the carotid artery. We used a diagnostic imaging device known as PET-CT to gauge levels of inflammation, which then shows up on the scan as a bright spot. We were able to set a threshold whereby the level of brightness corresponds to the highest stroke risk – thereby predicting the likelihood of a recurrent stroke for high risk patients,” said Professor Kelly.

Current international guidelines recommend that patients who present following a mini-stroke routinely undergo a number of diagnostic tests, one of which involves a carotid ultrasound to determine the extent to which the carotid artery has narrowed. However, this approach is limited in its effectiveness. The findings from Professor Kelly and his team point to plaque inflammation – not just narrowing - as the primary predictor of recurrent stroke.

“This could fundamentally change the way in which we target and treat patients who present following a mini-stroke. It means that we may be able to significantly reduce the number of people who suffer a second stroke during the high risk period by identifying and treating them more quickly. Further down the line, we can use these findings in trials by inventing drugs that attack and reduce levels of inflammation in the carotid artery.” said Professor Kelly.

“It’s important also to send the message that early diagnosis and treatment can only be effective if people recognise and act on the warning signs from the Irish Heart Foundation’s FAST campaign. A mini-stroke usually manifests itself in temporary and transient symptoms like slurred speech, loss of feeling in the limbs or blurred vision. People often ignore the symptoms because they usually disappear quickly, but a mini-stroke is a shot across the bow and should be treated as a medical emergency,” said Professor Kelly.

Dr Angie Brown, Irish Heart Foundation Medical Director said: “The Irish Heart Foundation's primary role is in cardiovascular disease prevention and supporting research. More recently we've had a leading role tackling stroke at all levels: prevention, stroke symptom awareness with a national act FAST campaign, patient support, driving a national stroke strategy and supporting vital research. Prevention is at the core of our work and it is especially rewarding for our donors to have funded research showing a new breakthrough in identifying patients at high risk of secondary strokes. We believe that in the future, this research will help save lives and reduce disability from stroke in Ireland and around the world.” 

The research was conducted through an alliance of the clinical, higher education and voluntary sectors, led by Professor Kelly and Dr Michael Marnane. The team comprised members from University College Dublin, the Mater University Hospital & St. Vincent’s University Hospital under the banner of the Dublin Academic Medical Centre. Significant funding was provided by the Irish Heart Foundation.

More Information:

  • 10,000 people in Ireland are admitted to hospital with stroke each year.
  • Stroke kills more than 2,000 people a year in Ireland – a higher death toll than from breast cancer, lung cancer and bowel cancer combined.
  • Stroke is the third most common cause of death and the most common cause of acquired physical disability in Ireland.
  • 350-500 lives per year could be saved if stroke unit care was introduced into Ireland.
  • There are 30,000 survivors of stroke in Ireland, many of whom have significant disabilities.
  • Approximately 80 per cent of strokes are caused by a blockage of an artery supplying blood to the brain. 20 per cent of strokes are caused by a bleed into the brain from a burst blood vessel.
  • Under-65s account for about one third of strokes.
  • Nearly one in three people will die within the first year after a stroke. Of those surviving, around 65 per cent will make a reasonable recovery.
  • For more see www.stroke.ie