Retrograde Autologous Priming in Cardiac Surgery: Results From a Systematic Review and Meta-analysis.

BACKGROUND: Retrograde autologous priming (RAP) before cardiopulmonary bypass (CPB) may minimize allogeneic red cell transfusion. We conducted a systematic review of the literature to examine the impact of RAP on perioperative allogeneic red cell transfusions in cardiac surgical patients. METHODS: This study involved a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies evaluating the use of RAP in cardiac surgery involving CPB. The primary outcome was intraoperative allogeneic red cell transfusion. Secondary outcomes included whole hospital allogeneic transfusions and adverse events such as acute kidney injury (AKI) and stroke. RESULTS: A total of 11 RCTs (n = 1337 patients) were included, comparing RAP patients (n = 674) to control (n = 663). In addition, 10 observational studies (n = 2327) were included, comparing RAP patients (n = 1257) to control (n = 1070). Overall, RAP was associated with a significantly reduced incidence of intraoperative red cell transfusion (n = 18 studies; odds ratio [OR] = 0.34; 95% confidence interval [CI], 0.22-0.55, P < .001) compared to controls. This effect was seen among RCTs (n = 10 studies; OR = 0.19; 95% CI, 0.08-0.45, P < .001) and observational studies (n = 8 studies; OR = 0.66; 95% CI, 0.50-0.87, P = .004) in isolation. RAP was also associated with a significantly reduced incidence of whole hospital red cell transfusion (n = 5 studies; OR = 0.28; 95% CI, 0.19-0.41, P < .001). Among the studies that reported AKI and stroke outcomes, there was no statistically significant increased odds of AKI or stroke in either RAP or control patients. CONCLUSIONS: Based on the pooled results of the available literature, RAP is associated with a significant reduction in intraoperative and whole hospital allogeneic red cell transfusion. Use of RAP may prevent hemodilution of cardiac surgical patients and thus, lessen transfusions. Additional high-quality prospective studies are necessary to determine the ideal priming volume necessary to confer the greatest benefit without incurring organ injury.