Association of Carotid Plaque and Serum Lipoprotein-Associated Phospholipase A2 (LP-PLA2) with Postoperative Delirium in Geriatric Patients Undergoing Hip Replacement: A Prospective Cohort Study

Background: The aim of this study was to investigate the relationships among carotid plaque (CP), serum lipoprotein-associated phospholipase (LP-PLA2), and POD in elderly patients. Material/Methods: Sixty-two elderly patients undergoing hip replacement with spinal-epidural anesthesia were divided into CP and non-CP groups based on the preoperative presence or absence of carotid atherosclerotic plaques, as assessed by ultrasound. POD was diagnosed by means of the Confusion Assessment Method (CAM). Blood samples were collected (preoperatively, postoperatively, and postoperative day 2) for the assessment of serum LP-PLA2 by enzyme-linked immunosorbent assay. The CP group was further divided into POD and no-POD subgroups based on the occurrence of POD. Results: The incidence of POD was higher in the CP group than in the non-CP group (P<0.05). While the LP-PLA2 level did not significantly differ between CP and non-CP groups preoperatively (P>0.05), it was higher in the CP group than in the non-CP group postoperatively and on postoperative day 2 (P<0.05). In the CP group, the LP-PLA2 level did not significantly differ between the subgroups preoperatively or postoperatively (P>0.05), but was significantly higher in the POD subgroup than in the no-POD subgroup on postoperative day 2 (P(0.05). Furthermore, the LP-PLA2 level on postoperative day 2 was an independent risk factor for POD (odds ratio: 1.03, 95% confidence interval: 1.00-1.07). Conclusions: The preoperative presence of carotid plaque is closely associated with a higher incidence of POD. The potential mechanism may involve the increased expression of LP-PLA2 in the serum, which can lead to plaque destabilization and subsequent inflammatory cascades.