Hypothesis: Patients who suffer from perioperative covert stroke will have reduced cognitive function 1 year postoperatively
Methods: 1114 patients over 65yo undergoing inpatient noncardiac surgery then underwent brain MRI after surgery, looking for acute brain infarct. These 1114 patients were then screened for cognitive dysfunction at 1 year out. The authors used multivariable regression to explore the association between perioperative covert stroke and cognitive decline 1 year after surgery (defined as a decrease of 2+ points on the MOCA from their preoperative baseline).
Results: 7% of patients had a perioperative covert stroke. Among those who completed the 1 year follow up cognitive assessment, 29 of 69 (42%) with covert stroke exhibited cognitive decline, vs 274 of 932 (29%) of those who did not experience perioperative covert stroke (Absolute risk increase of 13%, p = 0.0055). Covert stroke was also associated with increased risk of perioperative delirium, as well as overt stroke and TIA at 1 year out from surgery.
Strengths:
Multicenter and international
Blinded
Standardized outcome measures (MOCA, etc)
Sensitive measurement for detection of stroke (MRI)
Weaknesses:
Observational, non-randomized
Lack of control group
Follow up period possibly too long to assure that surgery was the greatest contributing factor to any observed cognitive decline
Clinical significance of outcome measures? (ie MOCA score change of 2 points)
Significant participant dropout occurred (~100 of 1114)
Key Point: Perioperative covert stroke occurred in 1 in 14 of patients 65 and older undergoing inpatient noncardiac surgery, ad it was associated with an increased risk for cognitive decline 1 year after surgery