Evidence of an association between brain cellular injury and cognitive decline after non-cardiac surgery

Abstract

BackgroundPostoperative cognitive dysfunction (POCD) is common after non-cardiac surgery, but the mechanism is unclear. We hypothesized that decrements in cognition 1 month after non-cardiac surgery would be associated with evidence of brain injury detected by elevation of plasma concentrations of S100β, neuron-specific enolase (NSE), and/or the brain-specific protein glial fibrillary acid protein (GFAP). MethodsOne hundred and forty-nine patients undergoing shoulder surgery underwent neuropsychological testing before and then 1 month after surgery. Plasma was collected before and after anaesthesia. We determined the relationship between plasma biomarker concentrations and individual neuropsychological test results and a composite cognitive functioning score (mean Z-score). ResultsPOCD (≥−1.5 sd decrement in Z-score from baseline) was present in 10.1% of patients 1 month after surgery. There was a negative relationship between higher plasma GFAP concentrations and lower postoperative composite Z-scores {estimated slope+−0.14 [95% confidence interval (CI) −0.24 to −0.04], P+0.005} and change from baseline in postoperative scores on the Rey Complex Figure Test copy trial (P+0.021), delayed recall trial (P+0.010), and the Symbol Digit Modalities Test (P+0.004) after adjustment for age, sex, history of hypertension and diabetes. A similar relationship was not observed with S100β or NSE concentrations. ConclusionsDecline in cognition 1 month after shoulder surgery is associated with brain cellular injury as demonstrated by elevated plasma GFAP concentrations.