As many as three million over-65s could be having so-called ‘silent strokes’ in the wake of surgery, new research suggests. The incidents often go unnoticed except in cases where brain scans are used, leading to underdiagnosis of cases.
Scientists at the Population Health Research Institute of Hamilton Health Sciences and McMaster University in Hamilton, Ontario, Canada led the study. They found that one in 14 post-operative patients had covert strokes when they monitored 1,000 individuals from North and South America, Asia, New Zealand and Europe.
When scaled up to take the entire world’s population into consideration, this could mean three million older people are suffering the attacks. The results of silent strokes can include increased risk of cognitive decline, delirium and even full strokes in the future.
Dr PJ Devereaux, co-principal investigator of the study, said: “We've found that 'silent' covert strokes are actually more common than overt strokes in people aged 65 or older who have surgery.”
Each of the participants in the study was undergoing elective, non-cardiac surgery and was given an MRI scan within nine days of the procedure. Seven per cent of the patients were found to have had a silent stroke without physicians noticing.
In the year that followed, those who had been found to have suffered a covert stroke were 13 per cent more likely to experience a decline in their cognitive performance, delirium or an overt stroke. This is due to a temporary disruption to the blood supply to the brain.
Dr Brian Rowe, scientific director of the Institute of Circulatory and Respiratory Health at the Canadian Institutes of Health Research (CIHR), said: “Vascular brain injuries, both overt and covert, are more frequently being detected, recognised and prevented through research funded by our Institute and CIHR.
“The NeuroVISION Study provides important insights into the development of vascular brain injury after surgery, and adds to the mounting evidence of the importance of vascular health on cognitive decline. The results of NeuroVISION are important and represent a meaningful discovery that will facilitate tackling the issue of cognitive decline after surgery.”