Abstract 246: High Density Lipoprotein Cholesterol Efflux Capacity And Delirium After Surgery

Abstract

Background: Postoperative delirium is associated with increased perioperative morbidity and mortality. Poor cerebrovascular health may increase delirium risk. We hypothesized that higher HDL concentration is associated with less postoperative delirium. Methods: After IRB approval, we prospectively recruited 65 adults undergoing major, elective cardiac and vascular surgery. Research staff performed preoperative dementia screening using the Mini Mental Status Exam (MMSE) and the Trail Making Test Part B. Postoperative Richmond Agitation Scale Scores and Confusion Assessment Method tool scores were collected from the medical record on postoperative days 1 and 2. Because HDL function often correlates with disease better than cholesterol level, HDL cholesterol efflux capacity (CEC) was measured in J774 macrophages loaded with 3 H-cholesterol in acetylated-LDL and then incubated with ApoB-depleted patient serum for 24 hours. Multivariate logistic regression was used to assess the association between HDL-C and HDL CEC and postoperative delirium, adjusted for age, preoperative MMSE score, preoperative Trail making score, and cardiopulmonary bypass exposure. Results: HDL-C was correlated with HDL CEC (Spearman’s R=0.37, p=0.002). One patient in the first (lowest) tertile, one patient in the second, and six patients in the third HDL-C tertile developed delirium. In contrast, four patients in the first tertile, three patients in the second, and one patient in the third tertile of CEC developed delirium. A higher preoperative HDL-C was independently associated with a higher odds of postoperative delirium (odds ratio 1.14 (95% CI 1.03, 1.26), p=0.01). In contrast, a higher preoperative HDL CEC was associated with a lower odds of delirium (odds ratio 0.82 (95% CI 0.68-0.99), p=0.04). Conclusions: Higher HDL CEC, but not HDL-C, was associated with less postoperative delirium. In this patient population, HDL function may play an important role in the development of postoperative delirium.