Intraoperative Lipoproteins Associated with Postoperative Delirium in a Prospective Observational Study of Older Adults Undergoing Cardiac Surgery

OBJECTIVE: To evaluate serum lipoproteins and other metabolites and their potential associations with the development of postoperative delirium. DESIGN: Prospective observational cohort study. SETTING: Single-site academic medical hospital. PARTICIPANTS: Patients age 60 years and older scheduled for major cardiac surgery with cardiopulmonary bypass (CPB). INTERVENTIONS: Delirium assessments were performed at baseline and twice daily up to postoperative day 3. The primary outcome evaluated serum collected before surgery, at the start and end of CPB, and on postoperative day 1. MEASUREMENTS AND MAIN RESULTS: Sixty-five patients were recruited, with 18% of subjects developing postoperative delirium within 3 days of surgery (10 of 57 subjects with complete cognitive assessments). Metabolomic analysis of serum revealed an association between the abundance of cholesterol in large high-density lipoprotein (L-HDL-C%) at the start of CPB and the development of postoperative delirium (odds ratio per standard deviation increment in biomarker concentration, 0.23; 95% confidence interval [CI], 0.08-0.66). Serum neurofilament light chain was inversely correlated with L-HDL-C% levels at the same time point (Spearman ρ, -0.39; 95% CI, -0.59 to -0.15) and was significantly higher at the end of CPB in subjects who developed delirium compared to subjects who did not develop delirium (median, 20.4 [interquartile range (IQR),16.1-25.4] pg/mL vs 11.9 [IQR, 7.9-16.9] pg/mL). CONCLUSION: Circulating blood biomarkers during surgery may provide insight into postoperative cognitive outcomes and should be evaluated in larger cohorts.