Association Between Perioperative Allogeneic Red Blood Cell Transfusion and Venous Thromboembolism After Major Surgery: A Retrospective Cohort Study.

Abstract

Previous observational studies demonstrated a significant association between allogeneic red blood cell (RBC) transfusion and an increased risk of postoperative venous thromboembolism (VTE). However, the confounding effects of procoagulant agent administration have seldom been addressed. This retrospective cohort study included patient who underwent major surgery between 2018 and 2022 at a general referral university-affiliated hospital located in Beijing, China. The exposure was the transfusion of allogeneic RBC products from the surgery day through 30 days postoperatively. The primary outcome was postoperative in-hospital VTE, diagnosed by venous ultrasound or computed tomography pulmonary angiography. Up to 37 patient- or treatment-related confounders, including anemia, estimated blood loss, fresh frozen plasma (FFP) transfusion, were adjusted for using multivariable logistic regression models and the propensity score overlap weighting. Among the 83,478 patients included, 8372 patients (10.0%) received perioperative RBC transfusion, while postoperative VTE occurred in 905 patients (1.1%). Among patients who received RBC transfusions, 75.9% also received FFP. In the unadjusted analysis, RBC transfusion was significantly associated with VTE (odds ratio [OR] = 5.09; 95% confidence interval [CI], 4.43-5.84; P < .001). However, this association was no longer significant after adjusting for all confounders using logistic regression (OR = 1.02; 95% CI, 0.78-1.33; P = .893) or the propensity score overlap weighting (OR = 1.02; 95% CI, 0.77-1.35; P = .874). FFP transfusion was associated with a higher risk of postoperative VTE (OR = 1.33; 95% CI, 1.10-1.62; P = .004). The effect of RBC transfusion on VTE was not modified by FFP transfusion (P for interaction = .612), and remained nonsignificant in either subgroup of patients receiving or not receiving FFP transfusion. After adjustment for confounders, perioperative RBC transfusion was not associated with an increased risk of postoperative VTE, whereas FFP transfusion showed a significant association with VTE.