There is substantial variation in transfusion practices across institutions, and the optimal transfusion threshold in vascular surgery is undefined.^1,2 It is unclear whether absolute hemoglobin number, the underlying cause of anemia, or other related factors play a role in adverse outcomes. We evaluated the association between blood transfusion and major adverse cardiovascular events (MACE) at different anemic thresholds in patients undergoing open vascular surgery.

This retrospective cohort study obtained data on patients undergoing elective open vascular operations from Society for Vascular Surgeons Vascular Quality Initiative (VQI) registries between January 1, 2003, and December 31, 2020. Cohorts were grouped by operation type (open abdominal aortic aneurysm [AAA] repair, suprainguinal bypass [SIB], or infrainguinal bypass [IIB]), preoperative hemoglobin level (severe: 7-10 g/dL, moderate: >10-12 g/dL, normal: >12 g/dL; to convert to grams per liter, multiply by 10.0), and transfusion status (with vs without perioperative transfusion). Patients with a hemoglobin level under 7 g/dL and urgent or emergent cases were excluded. In accordance with the Common Rule, this study was exempt from ethics review and informed consent requirement because deidentified data were used. We followed the reporting guideline.