Background: Prior studies have established an increased risk of overt stroke after noncardiac surgery, with significant associated morbidity and mortality. Similarly, covert stroke in the nonsurgical population is well described and has been shown to be associated with cognitive decline.
Study design: Prospective cohort study.
Setting: Academic centers in nine countries.
Synopsis: This study evaluated 1,114 patients older than 65 years who were hospitalized for noncardiac surgery, excluding patients with carotid and neurosurgical procedures. All enrolled participants completed diffusion-weight MRI of the brain within 9 days of surgery. Follow-up rates for clinical outcomes (1,112; greater than 99%) were excellent, and the primary outcome measure, follow-up Montreal Cognitive Assessment (MOCA) at 1 year, was defined in 1,001 (90%) of the study subjects.
Covert stroke was detected in 78 (7%) of the study participants. Those with covert stroke had a higher incidence of cognitive decline at 1 year (adjusted odds ratio, 1.98; 95% confidence interval, 1.22-3.2) with an absolute risk increase of 13%. Patients with covert stroke also had a higher rate of delirium within 3 days of surgery (hazard ratio, 2.24; 95% CI, 1.06-4.73) and a higher rate of overt stroke and transient ischemic attack at 1 year (HR, 4.13; 95% CI, 1.14-14.99).
This study helps to establish the incidence of covert stroke after noncardiac surgery and provides support for covert stroke as a risk factor for cognitive impairment.
Bottom line: Covert stroke following noncardiac surgery is common, affecting 1 in 14 patients in this study, and it is associated with an increased risk of cognitive decline, perioperative delirium, and subsequent overt stroke.
Citation: The NeuroVISION Investigators (Mrkobrada M et al.). Perioperative covert stroke in patients undergoing noncardiac surgery (NeuroVISION): a prospective cohort study. Lancet. 2019;394(10203):1022-9.
Dr. Herrle is a hospitalist at Maine Medical Center in Portland and at Stephens Memorial Hospital in Norway, Maine.
