Impact of Intraoperative High-volume Autologous Blood Collection on Allogeneic Transfusion During and After Cardiac Surgery: a Propensity Score Matched Analysis

Background: Perioperative use of allogeneic blood products is associated with higher morbidity, mortality, and hospital costs after cardiac surgery. Blood conservation techniques such as acute normovolemic hemodilution (ANH) report variable success. We hypothesized that large-volume ANH with limited hemodilution would reduce allogeneic blood transfusion compared to the standard practice.

Study Design And Methods: Retrospective observational study of cardiac surgery patients at the University of Maryland Medical Center between January 2014 and September 2017. Using the institutional Society of Thoracic Surgeons database 91 autologous and 981 control patients who underwent coronary artery bypass grafting, aortic valve replacement, or both were identified. After propensity matching of 13 preoperative characteristics, 84 autologous and 84 control patients were evaluated. Our primary endpoint was avoidance of blood transfusion during index hospitalization, and secondary endpoints were postoperative bleeding and major adverse outcomes.

Results: The median harvest volumes in the ANH and control groups were 1100 mL and 400 mL, respectively. Of the ANH group, 25% received any transfusion versus 45.2% of the control group after propensity score matching (p < 0.006). When controlling for preoperative platelet count, the transfusion rate ratios for ANH were 0.58 (95% confidence interval, 0.39-0.88) for RBCs and 0.63 (0.44-0.89) for non-RBC components, which were both found to be statistically significant. There was no difference found in major adverse events.

Conclusion: These results suggest that large-volume ANH is beneficial in reducing both RBC and non-RBC component usage in cardiac surgery. A further prospective validation is warranted.