The Association of Blood Transfusion With Free Flap Survival and Thrombosis: A Review and Meta-analysis.

[INTRODUCTION] As risk factors of free flap loss related to the patient are unmodifiable, proper perioperative protocol is crucial. Perioperative blood transfusion (PBT) may be associated with an increased risk of medical complications, prolonged length of stay, and an increased risk of surgical site infection. The question of this study is whether PBT in free flap reconstructions may be associated with flap failure and anastomosis thrombosis.

[METHODS] Preferred Reporting Items Systematic Review and Meta-Analysis protocol was used, and the literature search was performed on Pubmed, Embase, and Scopus. The risk of bias in individual studies was assessed through the Newcastle Ottawa Scale. Meta-analysis was performed.

[RESULTS] Fifteen articles were enrolled in the study, representing 7871 patients. Statistically significant risk ratios (RRs) were observed, indicating PBT was associated with an increased risk of both anastomosis thrombosis (RR 1.71, 95% confidence interval [CI] 1.12-2.59) and flap failure (RR 2.02, 95% CI 1.25-3.26). Further analysis led to the division of three subgroups due to the operation site. For breast reconstruction, the RR was 7.96 (95% CI 4.00-15.81) for flap failure and 2.94 (95% CI 1.88-4.61) for anastomosis thrombosis. For head and neck reconstruction, the RR were 1.22 (95% CI 0.86-1.73) and 1.02 (95% CI 0.59-1.75), respectively. In the mixed group, RR was 2.23 (95% CI 1.06-4.58) for flap failure and 1.23 (95% CI 0.59-2.56) for anastomosis thrombosis.

[CONCLUSIONS] Although overall PBT is associated with a higher incidence of flap necrosis and anastomosis thrombosis, this association is statistically significant only in breast reconstruction. Further prospective studies focusing on specific flap surgery types are warranted.