Predicting the Need for Infra-operative Large Volume Blood Transfusions During Thoraco-abdominal Aortic Aneurysm Repair

Objective: Thoraco-abdominal aortic aneurysm (TAAA) repair is a complex procedure performed in patients at high cardiovascular risk. High volume intra-operative bleeding is often recorded, and the amount of intra-operative blood product transfusion is associated with relevant morbidity and mortality. The aim of the study was to identify pre-operative predictors of intra-operative large volume blood transfusions (LVBT) to stratify patients pre-operatively. Methods: This was a retrospective analysis of prospectively collected data of all patients who underwent open TAAA surgery at San Raffaele Scientific Institute from January 2009 to December 2015. Intra-operative red blood cell (RBC) transfusions were administered to maintain a hematocrit of at least 30%. A LVBT was defined as a transfusion of at least four RBC units, corresponding to 1000 mL. Results: The study population included 428 patients: 260 (61%) received fewer than 4 RBC units, and 168 (39%) were transfused with at least 4 RBC units. In patients who underwent LVBT, higher mortality was observed after surgery (p=.003), longer intensive care unit admission (p=.004), and longer mechanical ventilation compared with less transfused patients (p=.0002). The patients who received fewer units were administered a higher dose of heparin during the surgical operation compared with patients of the LVBT group: 340011100 vs. 290011300 IU (international units) (p=.0004). Pre-operative chronic renal failure (OR 1.8), the pre-operative haemoglobin value (OR 0.8), and the need for urgent or emergent surgery (OR 3.15) were independent predictors of LVBT on multivariate analysis. Conclusions: The identification of patients at risk of intra-operative LVBT during TAAA surgery is critical as these patients experience a worse outcome. Nevertheless, only few independent predictors are available for clinical practice. (C) 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.