Use of serum aβ1-42 and Tau biomarkers in the diagnosis of postoperative cognitive dysfunction

Abstract

Background: Postoperative cognitive dysfunction (POCD) can occur even after general anesthesia and sedation. Postoperative cognitive dysfunction depending on the type of surgery, ranges from 8.9% to 46.1%. Serum Aβ1-42 and Tau protein levels are used to diagnose POCD, dementia, and mild cognitive impairment (MCI). The application of the three-minute cognitive impairment questionnaire (after this referred to as 3D-CAM) to detect cognitive impairment in postoperative and intensive care unit patients, and the identification of biomarkers in blood serum for diagnosis can be used for early detection of this disorder, clarification of the understanding of pathogenesis, prediction and diagnosis. This could lead to better-targeted treatment management. Aim: Use of new novel serum biomarkers in the diagnosis of postoperative cognitive dysfunction Materials and Methods: A total of 34 people aged 65 and over who underwent surgery under general or regional anesthesia were included in the study. Baseline cognitive parameters were determined by the “Montreal Cognitive Assessment (MoCA)” within 24 hours before anesthesia and surgery, and the amount of Aβ1-42 and Tau protein in blood plasma before surgery and anesthesia was determined by biomarker analysis. Within 24 hours postoperative and anesthesia, delirium was assessed by the 3D-CAM method, and serum Aβ1-42 and Tau protein levels were repeatedly analyzed. Results: The average age of the participants was 70.18±5.50, 50% (n=17) were male and 50% (n=17) were female. A total of 34 patients participated in the study, 26 (76.47%) patients did not detect delirium, while 8 (23.53%) patients detected delirium. Within 24 hours preoperative and anesthesia, the score of “The Montreal Test for Assessment of Basic Cognitive Parameters (MoCA)” was 19.88±4.017 pg/ml in patients who were not delirium, and (13.38±9.07) pg/ml delirium in patients who were (13.38±9.07). Patients with moderate cognitive impairment had dementia. The level of Tau protein preoperative was 10.52 (3.22-15.78) pg/ml and postoperative it was 10.31 (3.37-14.28) pg/ml in patients who were not detected delirium (P=0.9751). In the group with delirium, it was 17.75 (3.59-25.69) pg/ml preoperative and 7.57 (3.07-15.95) pg/ml postoperative, which was a statistically significant decrease (P=0.0391). In the group without delirium, the preoperative Aβ1-42 protein level was 11.55 (9.180-13.92) pg/ml and 12.83 (10.05-15.60) pg/ml, or not statistical difference was observed (P=0.3767). The level of Aβ1-42 protein preoperative was 11.73 (9.736-13.73) pg/ml, and postoperative it was 12.39 (9.8914.87) pg/ml, and no statistical difference was observed (P=0.6406). When evaluating the sensitivity and specificity of the biomarker diagnostic method between Tau and Aβ1-42 proteins by ROC curve, the appropriate threshold value of preoperative Tau protein is >15.78, the sensitivity is 75%, the specificity is 73.08%, or it is more significant for diagnosis (P=0.007). Conclusions: 1. It was observed that patients aged 65 years and older who postoperative under general or regional anesthesia had higher levels of Tau protein in the blood plasma before anesthesia, and were more likely to postoperative delirium. 2. The diagnostic sensitivity and specificity of preoperative blood plasma Tau biomarkers for detecting postoperative delirium are good.