Effect of Preoperative CIMT on Hemodynamics During Liver Transplantation

Overview

Candidates for liver transplantation (CT) carry an increased risk of cardiovascular disease (CVD) due to underlying end-stage liver disease (ESHD) and immunosuppressive drugs used post-transplantation. CVD is a significant cause of long-term mortality after CT \[1\] \[2\]. Carotid Intima-Media Thickness (CIMT), a subclinical marker of atherosclerosis in the preoperative period, is a non-invasive method used to predict future CVD risk \[3\]. High CIMT indicates atherosclerosis and decreased arterial compliance. This can compromise organ perfusion and increase the risk of postoperative complications by increasing intraoperative blood pressure variability (BPV) during anesthesia induction and surgical stress in major surgeries such as CT. Studies investigating whether CIMT is an independent risk factor for perioperative hemodynamic instability in CT patients are limited. The aim of our study is to investigate the effect of CIMT values on intraoperative hemodynamic parameters. Secondary objectives are to determine the association of CIMT with the incidence of hypotension, vasopressor requirement, postoperative acute renal injury (ARI), and major cardiac adverse events (MCAE) after anesthesia induction. Theoretical Benefit: To make a significant contribution to the literature on the relationship between atherosclerosis and anesthesia management by determining whether CIMT is an independent predictor of perioperative hemodynamic instability in chemotherapy patients. Practical Benefit: To ensure the inclusion of CIMT measurement in the anesthesia risk assessment of chemotherapy candidates. Identifying patients with high CIMT will guide the implementation of more aggressive and targeted hemodynamic management strategies (e.g., more frequent invasive monitoring, proactive vasopressor use) during anesthesia induction and maintenance.

This study was planned as a retrospective observational cohort design to examine the relationship between carotid intima-media thickness (CIMT), routinely measured preoperatively and recorded by operating room devices, and intraoperative hemodynamic changes in patients undergoing liver transplantation. Liver transplantation is an advanced surgical procedure performed with a limited number of high-risk patients. CIMT measurement is a non-invasive ultrasonographic method routinely applied in clinical practice as part of cardiovascular risk assessment in liver transplant candidates. Intraoperative hemodynamic data are recorded as standard by operating room information systems. Therefore, the present study was planned by retrospectively analyzing data obtained in clinical practice, without introducing any additional intervention or risk to the patient. Retrospective design is considered a suitable method for evaluating rare outcomes (such as reperfusion syndrome) and analyzing real-life data. Retrospective, observational cohort study Inclusion criteria: Patients over 18 years of age who underwent liver transplantation (LT) at Dicle University Faculty of Medicine Hospital between January 1, 2023 and January 28, 2026, provided written informed consent, and had preoperative CIMT measurements will be evaluated. Exclusion criteria: Patients with carotid artery stenosis or plaque greater than 50%, a history of stroke or transient ischemic attack (TIA), and serious arrhythmias or heart failure that would affect the reliability of intraoperative hemodynamic data. Materials and Methods: The mean CIMT (mm) value measured by standard ultrasound in the preoperative period will be used. Intraoperative Data: All hemodynamic data (MAP, HR, vasopressor doses) from anesthesia induction to the end of surgery are measured every 2-5 minutes via automated recording systems. Intraoperative data will be reviewed and evaluated from the existing recording system. Explanation Regarding Statistical Methods to be Used: Mean ± SD or Median (MESD) will be used for continuous variables, and n (%) for categorical variables. For continuous variables, Independent Samples t-Test or Mann-Whitney U Test will be used. For categorical variables, Chi-square Test or Fisher's Exact Test will be used. The relationship between CIMT value and continuous variables such as KBV, duration of hypotension, and vasopressor dose will be examined using Pearson or Spearman Correlation Analysis. To determine whether CIMT is an independent risk factor for intraoperative hypotension or high KBV, Logistic Regression Analysis (for binary results) or Linear Regression Analysis (for continuous results) will be used, controlling for other clinical variables (age, MELD, BMI, etc.). All analyses will be performed using \[Statistical Software Name: E.g., SPSS 25.0, R, etc.\] and p \< 0.05 will be considered significant. Power Analysis: Since the study was planned retrospectively, the sample size was not predetermined. The adequacy of the current sample size was evaluated based on the development of reperfusion syndrome (RS), which is the primary endpoint. In the literature, the incidence of RS in liver transplant patients is reported to be approximately 30-40%. Accordingly, the expected number of RS events in a sample of N=50 patients was calculated to be approximately 15-20. Considering the events per variable (EPV ≥10) approach recommended for logistic regression analysis, the current sample size was evaluated as sufficient for a predictive model with a limited number of independent variables. In addition, in the evaluation performed for ROC analysis, it was predicted that the current sample size provided statistical power close to 80% under the assumption of moderate effect size (AUC ≈ 0.70).