Research in context
Evidence before this study
We searched MEDLINE, from database inception until June 20, 2019, using the search terms “stroke”, “noncardiac”, “non-cardiac”, “postoperative”, “perioperative” and “surgery”, restricted to publications in English, to identify studies in people aged 18 years or older evaluating the epidemiology or the impact of covert stroke after non-cardiac surgery. Less than 1% of adults having major non-cardiac surgery have an overt stroke. Although there are several studies showing that covert stroke is frequent after carotid artery procedures, we did not identify any study outside this population that examined the incidence or effect of covert stroke, with the exception of the NeuroVISION pilot study. We did not identify any study examining the relationship between perioperative covert stroke after non-cardiac surgery with 1-year cognitive decline.
Added value of this study
In this international, prospective cohort study of 1114 participants aged 65 years or older who underwent inpatient, elective, non-cardiac surgery and had brain MRI after surgery, perioperative covert stroke occurred in 7% of participants. Patients who had a perioperative covert stroke showed an increased risk of perioperative delirium, overt stroke, or transient ischaemic attack at 1 year, and cognitive decline (primary outcome) 1 year after surgery, compared with patients who did not have a perioperative covert stroke.
Implications of all the available evidence
Perioperative covert stroke occurs in a substantial number of patients aged 65 years or older and is associated with an increased risk of cognitive decline 1 year after non-cardiac surgery. Research is needed to establish prevention and management strategies for perioperative covert stroke.