Background:
Anemia is a common condition in patients suffering from end-stage liver disease (1). In previous studies, preoperative anemia was associated with greater mortality in patients undergoing major surgery (2,3). The aim of this study was to investigate whether preoperative anemia influences one-year mortality in patients undergoing orthotopic liver transplantation (OLT).
Methods:
This single-center retrospective study was performed at the Medical University of Vienna after local ethics committee approval. Patients undergoing their first OLT between 2004 and 2016 were included. Exclusion criteria were combined liver-kidney-transplantation and combined liver-lung-transplantation. Anemia was defined according to the classification of the WHO. Hemoglobin values were determined within 24 hours prior to surgery. To assess one-year mortality, a univariate cox regression model for death as event accounting for the combined factor of anemia (mild, moderate, and severe) was calculated.
Results:
We included 607 patients with a mean age of 53±8 years. Preoperatively, 24% (n=146) of patients had no anemia, while 76% (n=461) of patients suffered from anemia. Of the anemic patients, 28% (n=172) had mild anemia, 42% (n=252) had moderate anemia, and 6% (n=37) suffered from severe anemia. Mean age of non-anemic patients was 55±8 years while that of anemic patients was 53±10 years (P=0.01). During OLT, non-anemic patients required less intraoperative transfusion of red blood cell units than did anemic patients (2±3 versus 4±5 units, respectively, P<0.001). One-year mortality after OLT did not differ between patients without preoperative anemia (21% mortality) and those suffering from preoperative anemia (21% mortality, hazard ratio 0.91, P=0.66). 
Conclusion:
This retrospective study suggests that preoperative anemia is associated with increased intraoperative transfusion of red blood cell units but does not affect one-year mortality in patients with end-stage liver disease undergoing their first OLT.
References:
1. Stein J, et al. World J Gastroenterol. 2016;22(35):7908–25. 
2. Baron DM, et al. Br J Anaesth. 2014;113(3):416–23. 
3. Musallam KM, et al. Lancet 2011;378(9800):1396–407.

02 / The influence of preoperative anemia on one-year mortality after orthotopic liver transplantation