Preoperative transfusion in patients with sickle cell disease to prevent perioperative complications: a systematic review and meta-analysis.

BACKGROUND Sickle cell disease (SCD) is associated with perioperative vascular (SCD-related) and non-vascular complications. To minimize perioperative complications during elective surgery, either exchange blood transfusion or simple blood transfusion can be used. We systematically reviewed the literature and meta-analyzed randomized and observational trials comparing exchange transfusion to simple transfusion, as well as studies comparing preoperative transfusion to no transfusion to assess the relative risk (RR) and benefit of each strategy in sickle cell patients undergoing surgery. METHODS Medline, Embase, and the Cochrane-controlled trial register were searched to identify studies that evaluated exchange transfusion to simple transfusion, as well as studies comparing any form of blood transfusion with no transfusion. Studies were evaluated according to a priori inclusion criteria and critically appraised using established internal validity criteria. Pooled RR was estimated using a random effects model. RESULTS Three randomized trials and seven observational studies were included. We found there was no difference between exchange transfusion and simple transfusion for perioperative mortality, vascular, or non-vascular perioperative complications. However, transfusion-related complications (RR 2.41, 95% confidence interval (CI): 1.49-3.91) and the amount of blood transfused (mean difference 2.03, 95% CI: 1.23-2.83) were higher in those treated with exchange transfusion versus simple transfusion. Similarly, there was no difference in perioperative mortality, vascular, or non-vascular perioperative complications between those treated with preoperative transfusion strategy and no transfusion strategy. CONCLUSION Based on the current literature, neither preoperative exchange transfusion nor simple transfusion reduces perioperative complications in patients with SCD who are undergoing surgery; however, available studies were underpowered to detect a treatment effect.