Perioperative blood transfusion in anemic patients undergoing elective endovascular abdominal aneurysm repair

Although blood transfusion can be lifesaving in active hemorrhage or severe anemia, it is also associated with increased morbidity and mortality. Several trials have established this risk and therefore defined a restrictive standard for transfusion, but this threshold and the risk of transfusions have not been specifically examined in vascular surgery patients. We therefore sought to assess transfusion practices and outcomes of anemic patients undergoing elective endovascular aneurysm repair (EVAR).

The Vascular Quality Initiative database was queried for patients undergoing EVAR between the years 2008 and 2017. Anemic patients were included in the study and were further stratified into mild anemia, defined by a hemoglobin level of 10 to 13 g/dL in men or 10 to 12 g/dL in women, and moderate to severe anemia, defined by a hemoglobin level <10 g/dL. The primary study outcomes were in-hospital mortality and complications.

Among 27,777 EVAR patients, one-third (n = 9232) were anemic and included in the study. One-fifth (n = 1866) of anemic patients received a perioperative transfusion. Transfused patients were more likely to have a history of cardiovascular disease. In-hospital mortality was significantly higher for anemic patients who received transfusions, both in mild anemia (mortality, 3.6% vs 0.4% in no transfusion; P < .001) and in moderate to severe anemia (4.5% vs 1.3%; P < .01). Morbidity was also significantly higher, with anemic patients who received a transfusion having higher rates of myocardial infarction, congestive heart failure, dysrhythmias, renal complications, leg ischemia, respiratory complications, and reoperation compared with anemic patients who did not receive any transfusion. The 30-day mortality was also higher in transfused patients (P < .001). After adjustment for patients' demographics, comorbidities, and operative factors, transfusion in anemic patients was associated with a nearly 4.4-fold increased odds of in-hospital mortality (odds ratio [OR], 4.38; 95% confidence interval [CI], 2.72-7.05; P < .001) and 4.3-fold higher odds of any in-hospital complication (OR, 4.31; 95% CI, 3.47-5.34; P < .001). This was more pronounced among patients with mild anemia, with 5.7 times (OR, 5.7; 95% CI, 1.78-18.0) and 4.3 times (OR, 4.3; 95% CI, 3.46-5.29) the odds of in-hospital mortality and complications, respectively.

Among anemic patients undergoing elective EVAR, transfusion is associated with an increased risk of death and in-hospital complications, even after controlling for patients' comorbidities and operative factors. These data suggest that the restrictive use of blood transfusions might be safer in vascular surgery EVAR patients. Medical management of anemia may be warranted in these patients to reduce morbidity and mortality; however, further studies are needed to evaluate effectiveness.