Blood Transfusion Increases the Risk of VTE Following Surgery North American Registry

Red blood cell (RBC) transfusions are associated with a higher risk of venous thromboembolism (VTE) after surgery according to a registry study, led by Ruchika Goel, MD, has been recently published in JAMA Surgery.

Blood transfusion is a common treatment during the perioperative process in patients undergoing surgery. However, it may impair the balance of coagulation factors and the inflammatory cascade. Since hypercoagulation and inflammation are interlinked, a hypercoagulable state may be trigerred by the immunomodulatory and proinflammatory characteristics of RBC transfusion. Despite potential mechanisms, the association between perioperative RBC transfusions and postoperative VTE has not been clarified by any prior studies.

The database of the American College of Surgery National Surgical Quality Improvement Program (ACS-NSQIP) was a registry of 525 hospitals across North America, included 750,937 patients who had surgery in 2014. The authors aimed to investigate the effect of perioperative RBC transfusions on the development of postoperative VTE. Patients were followed during their hospital course and after discharge from hospital to 30 postoperative days. Perioperative RBC transfusion was defined as one or more RBC transfusion event from 72 hours before to 72 hours after surgery. The reference group consisted of patients who never received a perioperative RBC transfusion.

6.3% of the patients received at least one RBC transfusion. The total VTE rate after surgery was 0.8%. The association between perioperative RBC transfusions and VTE was significant for both, deep vein thrombosis (adjusted OR 2.2; 95% CI 2.1-2.4) and pulmonary embolism (adjusted OR 1.9; 95% CI 1.7-2.1). The risk of VTE were doubled within 30 days in patients underwent surgery with at least one RBC transfusion compare to those received none (adjusted OR 2.1, 95% CI 2.0-2.3). There was a significant dose-response effect as the number of transfusion events increased (P < .001 for trend). Furthermore, the analysis of surgical subgroups demonstrated that there was a significant association between perioperative transfusions and the development of VTE for each of surgical subspecialties included.

The results of this study highlighted that blood should be transfused only in patients with a clear indication in the perioperative course. Additionally, the use of anticoagulant therapy in this specific group of patients arises as an important focus for upcoming trials.