Lead Investigator: Professor Alison Halliday
Institution: University of Oxford
Grant type: Project grant
Duration: 21 months
Scientific Title: Does surgery for asymptomatic carotid stenosis reduce the risk of dementia? Long-term follow-up of the Asymptomatic Carotid Surgery Trial (ACST-1)
Why did we fund this project?
Comments from members of our Research Network:
'A worthwhile project which complements previous studies.'
'Useful project - makes use of data gathered on previous trial and could potentially inform surgeons and families faced with decision to operate or not.'
'This is an exciting project - especially in the large number of participants. It would also help participants make decisions in life-or-death cases.'
What do we already know?
Vascular dementia is caused by problems with the blood vessels in the brain, for example due to damage following a stroke. One cause of the condition could be the narrowing of these blood vessels, caused by blood clots or fat deposits. This narrowing could reduce blood flow to the brain, meaning that brain cells do not get the oxygen and nutrients that they need to survive and leading to symptoms of dementia.
One such blood vessel that could be affected is called the carotid artery, which is found each side of the neck and is a major supplier of blood to the brain. There is evidence that surgically unblocking this artery can help to prevent stroke and potentially delay or reduce the risk of dementia.
What does this project involve?
In 1993 to 2003, this research team performed a large randomised controlled trial, where they unblocked the artery in a group of people who had a narrowed carotid artery but did not have symptoms related to vessel damage or stroke. A second group of people did not receive the surgery unless they started to show symptoms. The aim of this study was to find out if the surgery could prevent stroke. In the 10 years that followed, the research team found that those who had the surgery before symptoms had fewer strokes.
The researchers now want to re-examine 1,600 of the participants to find out whether they have developed dementia and if there is any difference between the two groups. They will find this information using electronic health records and telephone interviews with family members of the person who took part in the trial.
How will this benefit people with dementia?
This research will give us a clearer idea of whether the narrowing of the carotid artery has a role in the development of dementia. It will also help doctors to give more information about the potential risks and benefits to people who are considering having surgery to correct this narrowing. The research could also give us more insights into whether widening damaged carotid arteries could be helpful in preventing or delaying cognitive decline or vascular dementia.