The interplay between pre-operative anemia and post-operative blood transfusion on survival following Fenestrated Aortic Aneurysm Repair

Abstract: Introduction Anemia is associated with a higher mortality following standard-EVAR. This study evaluates the impact of anemia on fenestrated endovascular aortic repair (FEVAR) for complex AAA repair. Methods All elective-FEVAR’s performed between 2010-2018 at a tertiary vascular-centre were analysed. Anemia was defined as a pre-operative haemoglobin (Hb) of 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 132 FEVAR patients were followed-up for 3.7(2.2) years. 38-patients were anaemic (average Hb of 112(13)g/L). Groups were comparable for age, AAA diameter, BMI and co-morbidity. Anaemic patients had a lower baseline eGFR (64.1(23.2) vs. 70.9(18.8) mL/min/1.73m2)(P=0.022) and a longer procedural time (242(103)minutes vs. 195.4(88)minutes (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 vs. non-anaemic 21%(P=0.04) at the end of follow-up. Anaemic patients had more post-operative MI’s (4 vs. 2, P=0.037) and a longer-LOS (9.2(7.1) versus 6.3(6.8) days(P=0.001)). Increasing Hb increased the likelihood of survival (HR -0.8(0.65-0.94) (p=0.038)). Post-operative transfusion was adversely associated with survival (HR 3.65 (1.05 – 12.8), p=0.043). Conclusion Anemia appears to be associated with an increased rate of post-operative MI, LOS, frequency of blood-transfusion and mortality rate following FEVAR but this surpassed by post-operative blood transfusion. Optimisation of pre-operative Hb should be considered as a potential target for improvements in clinical outcomes and hypothetically a consequential reduction in post-operative RBC transfusion need.