A novel risk assessment tool for postoperative delirium in vascular surgery: The stress model (Siena posTopeRative dElirium in vaScular Surgery)

Objective: Postoperative delirium (POD) is a common complication with a high health-related impact. The creation of a model (Siena posTopeRative dElirium in vaScular Surgery) to identify high-risk patients with consecutive prompt diagnosis and correct management. Methods: This is an observational retrospective study to evaluate POD incidence in patients who underwent elective vascular surgery procedures between 2018 and 2020. POD was detected using CAM and defined as the onset of an acute confusional state, clinically manifesting as a disturbed state of consciousness, cognitive dysfunction, or alteration in perception and behavior. The total population was divided in the development and validation subsamples. Multivariable logistic regression analysis was performed, identifying variables related to the occurrence of POD. An additive score was created and the STRESS score was internally validated using the Validation subgroup. Results: A total of 1067 patients were enrolled. POD occurred in 111 cases (10.4%). Multivariable logistic regression analysis for POD occurrence revealed as significant predictors: age>75 years, CKD, dyslipidaemia, psychiatric disease, CAD, hospitalization in the previous month, preoperative NLR >3.59, preoperative Hb < 12 g/dl, preoperative Barthel score <75, major amputation, CLTI revascularization, general anesthesia, and postoperative urinary catheter. These variables were used to create the STRESS score. The model was applied to both development and validation subgroups; AUC was respectively 0.7079 (p < .0001) and 0.7270 (p < .0001). Conclusion: The STRESS score has a good predictive potentiality for POD occurrence in elective vascular surgery procedures. However, implementation and external validation are needed to be correctly used in everyday clinical practice.