The Interplay between Preoperative Anemia and Postoperative Blood Transfusion on Survival following Fenestrated Aortic Aneurysm Repair.

Background: Anemia is associated with a higher mortality following standard endovascular aortic repair (EVAR). This study evaluates the impact of anemia on fenestrated endovascular aneurysm repair (FEVAR) for complex aneurysm (AAA) repair.
Methods: All elective FEVARs performed between 2010 and 2018 at a tertiary vascular center were analyzed. Anemia was defined as a preoperative hemoglobin (Hb) of <120 g/L for women and <130 g/L for men (World Health Organization definition). Primary outcome was overall survival by Kaplan-Meier. Secondary outcomes included length of hospital stay (LOS) and myocardial infarction (MI). Cox proportional hazard analyses were conducted.
Results: In total, 132 FEVAR patients were followed up for 3.7 (2.2) years. Thirty-eight patients were anemic [average Hb of 112 (13) g/L]. Groups were comparable for age, AAA diameter, body mass index, and comorbidity. Anemic patients had a lower baseline estimated glomerular filtration rate [64.1 (23.2) vs. 70.9 (18.8) mL/min/1.73 m ² , P = 0.022] and a longer procedural time [242 (103) vs. 195.4 (88) min, P = 0.009] with no difference in the number of fenestrations (P = 0.696). Kaplan-Meier analysis demonstrated a higher mortality (log-rank P = 0.03) with 40% deceased versus 21% nonanemic (P = 0.04) at the end of follow-up. Anemic patients had more postoperative myocardial infarctions (MIs) (4 vs. 2, P = 0.037) and a longer LOS [9.2 (7.1) vs. 6.3 (6.8) days, P = 0.001]. Increasing Hb increased the likelihood of survival [hazard ratio, HR -0.8 (0.65-0.94), P = 0.038]. Postoperative transfusion was adversely associated with survival [HR 3.65 (1.05-12.8), P = 0.043].
Conclusions: Anemia appears to be associated with an increased rate of postoperative MI, LOS, frequency of blood transfusion, and mortality rate following FEVAR but this surpassed by postoperative blood transfusion. Optimization of preoperative Hb should be considered as a potential target for improvements in clinical outcomes and hypothetically a consequential reduction in postoperative red blood cell transfusion need.
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