Evaluation of vitamin D deficiency - insufficiency and its effects on postoperative cognitive functions in patients undergoing coronary bypass surgery

Introduction: Postoperative cognitive dysfunction (POCD); It is defined as a state of cerebral cognitive change that can have long-term effects after anesthesia and surgery, characterized by impaired attention, concentration, and memory. It is not a complete psychiatric diagnosis and is considered as a mild neurocognitive disorder. Neurocognitive regression can be observed as the main neurological complications after coronary artery bypass surgery. Vitamin D may help prevent neurodegeneration as it plays an important role in the regulation of neurotrophic factors, neurogenesis, calcium homeostasis, detoxification and clearance of β-amyloid. In our study we aimed to evaluate whether the preoperative vitamin-D levels of patients who will undergo CABG surgery have an effect on postoperative neurocognitive functions. Materials and Methods: Between May 2021 and November 2022, 100 patients with ASA 1-3 risk score, aged 18-70 who were scheduled for elective CABG surgery at Akdeniz University Medical Faculty Hospital Anesthesiology and Reanimation Clinic, were included in the study. All patient were divided into 2 groups. While Vitamin D insufficiency group has 21-29 ng/ml serum 25(OH)D3 level, Vitamin D deficiency group has less than 20 ng/ml serum 25(OH)D3. Demographic characteristics of the patients, age, gender, BMI, educational status, comorbidities and medications, alcohol abuse, ASA classification, preoperative left ventricular ejection fraction value, preoperative 25 OH vitamin D level, NYHA (New York Heart Association Functional Classification) classification, EuroSCORE 2 values were recorded. MOCA cognitive assessment test was applied to the patients 1 day before the operation and 5-7 days after operation. NIRS monitoring was applied to the patients during the surgery. S100B and CXCL10 Ligand were measured preoperatively and at the postoperative 48th hour. The length of stay of the patients in the intensive care unit and hospital, APACHE2 score in the first 24 hours postoperatively and CASUS score for 5 days postoperatively were also calculated and recorded. While evaluating the findings, they were evaluated using the SPSS 23.0 statistical program for statistical analysis. For statistical significance, the p value was determined to be less than 0.05. Results: Demographic data and perioperative characteristics of the patients in the two groups with vitamin D deficiency (70 case) and insufficiency (30 case) were similar, except for Hypertension (HT). HT was observed significantly higher in patients with preoperative vitamin D deficiency (67.1%) than in patients with insufficiency (43.3%) (p=0.045). POCD was observed in 27.8% of the patients included in the study. 27 cases of POCD; Vitamin D deficiency was detected in 6 of them, and vitamin D deficiency was detected in the remaining 21. When the effect of vitamin D levels on the development of POCD was analyzed; POCD developed in 30% of patients with vitamin D deficiency and in 20% of patients with vitamin D insufficiency. Although a higher rate of POCD was observed in patients with vitamin D deficiency, this difference was not statistically significant (p=0.437). In the subgroup analysis of the data, the ages of 27 patients who developed POCD (66); It was found to be significantly higher than 70 patients (60) who did not develop POCD (p=0.010). 10% of the patients who did not develop POCD and 29.6% of the patients who did develop POCD were female, and the female gender was statistically significantly higher for the development of POCD (p=0.037). A significant correlation was found between the development of POCD and the ASA classification (p=0.032). The rate of ASA 2 is significantly higher in patients who do not develop POCD and the rate of ASA 3 is significantly higher in patients who develop POCD. In 27 cases with POCD; mean MV adherence time [p=0.027], length of stay in the intensive care unit [p=0.015], length of stay in the hospital [p<0.001] were found to be significantly longer. No significant difference was found between cerebral desaturation and POCD development in NIRS monitoring. When the patients who developed hypotension during the period of deterioration in NIRS values (CPB entry and cross-clamp removal) were also examined, POCD development was observed at a similar rate to the patients who did not develop hypotension. Median preop S100B values of all patients were 34.51 (26.79-46.34), postoperative S100B values were 48.37 (35.52-64.34), preop CXCL 10 values were 71.32 (62.05-83.67) and postoperative CXCL 10 values were calculated as 89.33 (70.02-120.95). Although both S100B and CXCL 10 values increased in the postoperative period compared to the preoperative period in all patients, no statistically significant increase was observed in those with vitamin D deficiency compared to the insufficiency (p>0.05). According to the analyzes performed, a negative correlation was found between the postoperative CXCL 10 value and the postoperative MOCA score (r=-0.312; p=0.004) Conclusion: In patients who underwent isolated CABG surgery with vitamin D deficiency/deficiency; We have seen that POCD risk factors such as advanced age, HT, DM, especially in deficient ones, are compatible with the literature. We found that cerebral biochemical markers were elevated in patients who developed POCD in the postoperative period. We believe that in addition to the detection of risk factors in patients who will undergo cardiac surgery, optimizing the preoperative vitamin D level and applying neuromonitoring in the perioperative period will both reduce the development of POCD and reduce the cost due to the length of stay in the intensive care unit and hospital, and this will be supported by studies with larger case series. Key Words: Vitamin D Insufficiency, Postoperative Cognitive Dysfunction, Coronary Artery Bypass Surgery, Montreal Cognitive Assessment Scale, Biochemical Markers, Near Infrared Spectroscopy