The effect of incremental increases in the number of packed red blood cell units transfused on perioperative outcomes in open abdominal aortic aneurysm repair.

Introduction: Despite abundant evidence in the surgical and critical care literature demonstrating inferior outcomes in transfused patients, liberal use of blood transfusion, particularly after the initial unit, remains common in vascular surgery. We therefore sought to investigate the incremental risk of each additional unit of blood transfused intraoperatively for patients undergoing elective open repair of abdominal aortic aneurysm (AAA) with regards to postoperative mortality and complications.

Methods: Patients in the Vascular Quality Initiative registry undergoing elective open infrarenal AAA repair from 2003 to 2020 were included. Exclusion criteria were age greater than 90, prior aortic surgery, concomitant iliac aneurysm, and concomitant additional major procedure. Multivariable logistic regression was used to calculate adjusted odds ratios for in-hospital mortality with incremental increases in packed red blood cells (pRBCs) given intraoperatively. Univariate analysis was performed for secondary outcomes including postoperative cardiac, respiratory, renal, and wound complications.

Results: Of 4608 patients who underwent elective open AAA repair, 796 patients (16.9%) underwent perioperative transfusion. The overall in-hospital mortality rate was 2.5%. Adjusting for relevant factors, there was an increase in the odds of in-hospital mortality of 24% for each additional unit transfused. Incremental increases in the number of units transfused were associated with significantly higher risk of postoperative myocardial infarction, congestive heart failure, pulmonary complications, renal failure, and wound complications.

Discussion: There appears to be an important increase in the odds of mortality for each additional unit transfused during infrarenal open AAA repair even when controlling for confounders.