Association of red blood cell transfusion and postoperative outcomes after endovascular aortic repair.

Argalious, Maged Y; Dalton, Jarrod E; Mascha, Edward J; Cywinski, Jacek B; Clair, Daniel G

BACKGROUND Several studies have documented worse postoperative outcomes in patients who received red blood cell (RBC) transfusion perioperatively during cardiac surgery or in critical care settings. These findings were attributed to activation of the inflammatory response with the release of cytokines and immune suppression. The aim of this study was to evaluate the association of RBC transfusion on the day of surgery and postoperative outcomes following endovascular aortic repair (EVAR). METHODS A total of 510 patients who underwent EVAR from April 2005 to March 2007 were considered for analysis. The exposure of interest was whether or not patients receive RBC transfusion on the day of surgery. The primary outcome was a composite in-hospital morbidity/mortality outcome. The authors assessed the association between RBC transfusion and our composite outcome using logistic regression after adjusting for the available potential confounders using propensity score matching. RESULTS Propensity scores were estimated for 418 out of the 510 patients; 92 patients were not included because of missing data. Propensity matching resulted in 42 successfully matched pairs. Median (quartiles) propensity score was 0.46 (0.28, 0.66) for the matched patients with transfusion and 0.46 (0.29, 0.61) for the matched patients without transfusion (P = .75, Wilcoxon rank sum test). Results of the multivariable model developed after propensity score matching suggest that RBC transfusion was not significantly associated with experiencing a postoperative complication; estimated odds ratio (95% confidence interval) of 2.7 (0.8, 9.0), P = .11. CONCLUSION In this study, RBC transfusion was not independently associated with an increased incidence of in-hospital morbidity and mortality after EVAR.