Impact of Postoperative Anemia and Transfusion in Patients Undergoing Complex Endovascular Aortic Aneurysm Repair

While anemia in patients undergoing endovascular aortic repair (EVAR) has been associated with negative outcomes, the impact of transfusion remains unclear and controversial. This study evaluates the impact of postoperative anemia and red blood cell transfusion in patients undergoing complex EVAR (CEVAR) including fenestrated-branched and chimney EVAR.

The Society for Vascular Surgery Vascular Quality Initiative was queried for patients undergoing CEVAR with incorporation of 1 or more viscerorenal vessels from 2014 to 2020. Patients were grouped by postoperative nadir hemoglobin (Hgb) level (<7, 7-8, 8-9, 9-10, >10 g/dL), then stratified by transfusion status. The primary endpoint was major adverse cardiac events (MACE), including myocardial infarction, heart failure, dysrhythmia, and stroke. Secondary endpoints included in-hospital mortality and 1-year survival.

In total, 4,966 patients met criteria for analysis including 9% with Hgb <7, 14% with Hgb 7-8, 16% with Hgb 8-9, 17% with Hgb 9-10, and 43% with Hgb >10. The rate of transfusion correlated inversely by lowest Hgb level: 89%, 74%, 40%, 21%, 6%, respectively. MACE, in-hospital mortality and 1-year survival correlated with Hgb level, with the worst outcomes in the lowest level. MACE was significantly higher for patients that received transfusion across all Hgb groups: 33.42% vs. 15.63%, P = 0.048; 23.38% vs. 14.04%, P = 0.008; 18.69% vs. 5.97%, P < 0.0001; 14.44% vs. 6.55%, P = 0.0006, and 13.08% vs. 3.43%, P < 0.0001, respectively. In-hospital mortality was significantly higher for patients that received transfusion in all groups except Hgb <7. On multivariable analysis transfusion remained an independent predictor for MACE and in-hospital mortality.

Postoperative anemia in patients undergoing CEVAR is associated with worse outcomes. However, rather than attenuating the negative impact of anemia, transfusion is independently associated with increased MACE and in-hospital mortality. These findings suggest potential harm of liberal transfusion and support the practice of using a hemoglobin level of 7 g/dL as the threshold for transfusion in stable patients that are not actively bleeding. Further study is necessary to determine the optimal transfusion threshold for patients undergoing CEVAR.