Stroke is the third commonest cause of death in Ireland and the leading cause of acquired disability here. Blockages in the large neck arteries cause 10-20% of one stroke type and are associated with a 3-fold increased risk of an early second stroke.

As part of the Dublin Carotid Artery Stroke Study (DUCASS) researchers from University College Dublin and the Mater and St Vincent’s hospitals are looking at ways of identifying people at risk of having a recurrent stroke. One particular type of stroke is caused by a narrowing of one of the arteries in the neck. Until now, the risk of a further stroke has been worked out on the basis of how much the carotid artery is blocked by “sludge” attached to the wall of the vessel.

However, among patients with the same amount of carotid stenosis, some are at very high risk of developing a stroke within days or weeks while for many others the risk of a recurrent stroke seems not as great. This makes it hard for doctors to prioritise who to treat first; some patients at low stroke risk undergo surgery to remove the blockage while other high-risk patients may suffer a disabling stroke before carotid surgery is performed.  It means new ways of defining risk in patients with carotid artery disease are needed.

Prof Peter Kelly, a clinical investigator with the Health Research Board and consultant neurologist at the Mater hospital along with Dr Michael Marnane, Dr Aine Merwick and colleagues are currently researching how different medical tests might better predict the risk of a recurrent stroke. With funding from the Irish Heart Foundation, they are using the latest scanning technology to look inside the blockages in the arteries to see how much inflammation is inside. Greater inflammation means the plaques (blockages) are more likely to destabilize and break off, causing a stroke.

Early research results suggest a scanning technique called positron emission tomography (PET) can predict patients in whom a stroke is likely to recur within a 90 day period. The researchers have found that the results of an ultrasound investigation called transcranial Doppler (TCD) also help predict those at higher risk.  With further work, the research team hopes to find a way of calculating those at higher risk of a further stroke and therefore who would benefit from early bypass surgery or having a stent placed in the blocked vessel.