Introduction: Radical cystectomy (RC) is associated with significant morbidity including perioperative blood transfusion. The aim of this study was to develop a model that would provide information on the relationship between perioperative blood transfusion and the development of venous thromboembolism (VTE) after RC. Methods: All patients who underwent open RC between between january 2006 and december 2021 at our institution were reviewed retrospectively. Patient with a history of prior VTE, those taking anticoagulation prior to surgery, patients with metastatic bladder cancer or with missing data were excluded. A venous thromboembolism was defined as either a deep venous thrombosis or pulmonary embolism. Patients who developed a VTE within 90 days after surgery were compared to those who did not. Logistic regression was performed to assess the association between covariates and the probability of VTE within 90 days after surgery. Results: A total of 372 cases were enrolled in this study. Almost 224 patients (60.21%) received a perioperative blood transfusion, with a median of 1 (IQR: 0-4) unit transfused. Forty-two patients (11.29%) of whom developed a VTE within 90 days after surgery. There was no significant difference in age, sex, race, Charlson score, clinical stay, BMI. Patient who developed a VTE experienced a longer mean operative time (367.84 vs 311.5 minutes, p=0.01), had adverse pathology (=pT3 or node positive) (p=0.005) and received a greater mean number of transfused units of blood during their stay (2.42 vs 1.26, p=0.02). The variables included in the model were selected based on the univariate analysis and on an a priori basis and included blood transfusion, age, BMI, Charlson score, smoking status, pathologic tumor stage, pathologic nodal stage and operative time. On multivariable logistic regression, each unit of transfused blood given during a patient's hospital stay was significantly associated with development of VTE (OR 1.22, 95% CI 1.12-1.44), as was operative time (OR 1.47, 95% CI 1.16-1.88). Conclusions: The incidence of perioperative blood transfusion is significant at the time of radical cystectomy. This study demonstrates that blood transfusion was associated with an increased risk for developing the VTE. SOURCE OF Funding: None
