Postoperative Blood Transfusion as an Independent Predictor of Morbidity and Mortality After Carotid Endarterectomy: A Single-Centre Retrospective Cohort Study

Objective: To determine the prevalence and independent predictors of postoperative blood transfusion following carotid endarterectomy (CEA) and to quantify its association with in-hospital morbidity and 30-day mortality. Methods: A retrospective, single-centre cohort study was conducted. All consecutive patients undergoing CEA for carotid artery stenosis for two years were included without exclusion criteria. Preoperative and serial postoperative haemoglobin (Hb) and platelet values were collected at 6, 12, 24, and 48 h after surgery, together with demographic variables, cardiovascular risk factors, neurological presentation, anaesthetic risk (ASA classification), operative details, transfusion characteristics, postoperative complications, length of stay, and 30-day mortality. Red cell concentrate was indicated when postoperative Hb was ≤9 g/dL and platelet concentrate when postoperative platelets fell below 100 × 103/mm3. The primary outcome was 30-day mortality. Univariate and multivariate linear regression analyses were used to identify independent predictors of mortality and transfusion need. Statistical significance was set at p < 0.05; analyses were performed with SPSS v30.0. Results: A total of 182 patients underwent CEA; 87.4% were male with a mean age of 71.84 years. The 30-day mortality rate was 3.8% (n = 7). Blood transfusion was required in 8.2% of patients (n = 15). On multivariate analysis, postoperative transfusion (p = 0.001) and postoperative complications (p = 0.001) were the only independent predictors of mortality, with transfusion conferring an approximately five-fold increase in mortality risk (relative risk [RR] 4.99; 95% confidence interval [CI] 0.88–28.24). Transfused patients had significantly higher complication rates (60.0% vs. 13.8%; p < 0.001) and longer total hospital stays (11.2 ± 14.9 vs. 4.9 ± 2.3 days; p = 0.001). On multivariate analysis, independent predictors of transfusion were low preoperative Hb (p < 0.001), peripheral arterial disease (PAD; RR 5.09, 95% CI 1.70–15.21; p = 0.002), postoperative complications (p = 0.004), and prolonged hospital stay (p < 0.001). Conclusions: Postoperative blood transfusion is an independent risk factor for mortality after CEA, multiplying mortality risk approximately five-fold. Low preoperative Hb and peripheral arterial disease are the principal preoperative predictors of transfusion requirement. These findings underscore the importance of systematic preoperative anaemia optimisation and the application of evidence-based restrictive transfusion thresholds in patients undergoing carotid surgery.