The additive effects of anaemia and transfusion on long-term survival after coronary artery bypass surgery

OBJECTIVES

To compare the independent and combined effects of anaemia and red blood cell transfusion on late survival after isolated coronary artery bypass grafting.

METHODS

Retrospective analysis of 5243 consecutive patients undergoing primary isolated coronary artery bypass grafting, performed from 2000 to 2015, in a Portuguese Academic Hospital. We identified 1649 patients with preoperative anaemia (A+) and 1422 patients who received a perioperative transfusion (T+)-the 4 possible combinations allowed for the creation of 4 subgroups (A-/T-, A-/T+, A+/T- and A+/T+). The primary endpoint was all-cause mortality at 10 years. We employed inverse probability weighting to control for confounding variables.

RESULTS

Thirty-one percent of the patients had preoperative anaemia, and 27.0% had at least one packed red blood cell transfusion. Inverse probability weighting was effective in eliminating differences in all significant baseline characteristics. The primary endpoint of all-cause mortality at 10 years occurred in 568 patients (20.5%) in the A-/T- group, as compared with 204 (24.4%) in the A-/T+ group (hazard ratio, 1.14; 95% confidence interval, 1.00 to 1.31; P = 0.053), 358 (33.8%) in the A+/T- group (hazard ratio, 1.53; 95% confidence interval, 1.38 to 1.71; P < 0.001), 254 (43.6%) in the A+/T+ group (hazard ratio, 2.25; 95% confidence interval, 1.97 to 2.56; P < 0.001).

CONCLUSIONS

This longitudinal, population-level study emphasizes the adverse long-term outcomes of preoperative anaemia and perioperative red blood cell transfusion. It stresses the importance of an evidence-based, multimodal and multidisciplinary approach to conserving blood resources and optimizing outcomes in patients at high risk for transfusion.