Outcomes in Patients Undergoing Cardiac Surgery Who Decline Transfusion and Received Erythropoietin Compared to Patients Who Did Not: A Matched Cohort Study.
BACKGROUND
Erythropoiesis-stimulating agents, such as erythropoietin (EPO), can be used to treat preoperative anemia. Some studies suggest an increased risk of mortality and thrombotic events, and use in cardiovascular surgery remains off-label. This study compares outcomes in cardiac surgery patients declining blood transfusion who received EPO with a matched cohort who did not.


METHODS
After institutional review board approval, we conducted a retrospective review of all patients who decline blood transfusion who underwent cardiac surgery and received EPO between January 1, 2004, and June 15, 2015, at a single institution. Control patients who did not receive EPO and were not transfused allogeneic red blood cells perioperatively were identified during the same period. Two controls were matched to each EPO patient using an optimal matching algorithm based on age, date of surgery, gender, operative procedure, and surgeon. The European System for Cardiac Operative Risk Evaluation (EuroSCORE) and baseline characteristics remaining unbalanced in the matched cohorts were controlled for in assessing patient outcomes. The primary outcome was a composite of mortality and thrombotic events, and secondary outcomes included change in hemoglobin (Hb) from baseline to discharge, acute kidney injury (AKI), sternal wound infection, atrial fibrillation, time to extubation, intensive care unit, and hospital length of stay (LOS).


RESULTS
Fifty-three patients who decline transfusion and received EPO were compared to 106 optimally matched control patients who did not receive EPO or red blood cell transfusion in the perioperative period. The median additive EuroSCORE was similar between the EPO and control group [6 (4, 9) vs 5 (3, 7), respectively; P = .39]. There was no difference in the primary outcome (P = .12) and mortality was zero in both groups. The EPO group had a higher mean preoperative Hb (13.91 g/dL vs 13.31; P = .02) and a smaller change in Hb from baseline (-2.65 vs -3.60; P = .001). The incidence of AKI (47.17% vs 41.51%; P = .49) was similar and there was no significant difference in all other outcomes, including time to extubation, hospital LOS, or intensive care unit LOS.


CONCLUSIONS
In this retrospective matched cohort study of patients declining transfusion and receiving EPO matched to control patients, there were no clinically meaningful differences in the outcomes.