Structural disconnectivity in postoperative delirium: A perioperative two‐center cohort study in older patients

BACKGROUND Structural disconnectivity was found to precede dementia. Global white matter abnormalities might also be associated with postoperative delirium (POD). METHODS We recruited older patients (≥65 years) without dementia that were scheduled for major surgery. Diffusion kurtosis imaging metrics were obtained preoperatively, after 3 and 12 months postoperatively. We calculated fractional anisotropy (FA), mean diffusivity (MD), mean kurtosis (MK), and free water (FW). A structured and validated delirium assessment was performed twice daily. RESULTS Of 325 patients, 53 patients developed POD (16.3%). Preoperative global MD (standardized beta 0.27 [95% confidence interval [CI] 0.21–0.32] p < 0.001) was higher in patients with POD. Preoperative global MK (−0.07 [95% CI −0.11 to (−0.04)] p < 0.001) and FA (0.07 [95% CI −0.10 to (−0.04)] p < 0.001) were lower. When correcting for baseline diffusion, postoperative MD was lower after 3 months (0.05 [95% CI −0.08 to (−0.03)] p < 0.001; n = 183) and higher after 12 months (0.28 [95% CI 0.20–0.35] p < 0.001; n = 45) among patients with POD. DISCUSSION Preoperative structural disconnectivity was associated with POD. POD might lead to white matter depletion 3 and 12 months after surgery.