DELIRE: Impact of perioperative anaemia in cardiac surgery: a retrospective observational study comparing different levels of haemoglobin

Introduction anaemia around cardiac surgery (CS) is an independent risk factor for adverse outcomes but transfusion is also associated with morbidity and mortality. However, evidences are still scarce to recommend a transfusion trigger, as in many studies, haemoglobin values in both restrictive and liberal groups were often higher than the planned thresholds. Objective to assess which nadir haemoglobin threshold is linked to morbidity and mortality within the 4 first days after cardiac surgery. Methods retrospective observational study from data collected between May 2013 and January 2018 in the cardiac surgery ICU (CS ICU) of Grenoble Alps University Hospital. 3 groups were compared based on the lowest haemoglobin measurements within the 4 first days after surgery: group 1 under 80g/L, group 2 between 80 and 95 g/L, group 3 no values under 95g/L. Main outcome measured: a composite index including 30-day all-cause mortality, and morbidity: myocardial infarction, low cardiac output syndrome, and renal failure. Results Files from 2220 patients how underwent CS were analysed, 263 in group 1, 575 in group 2 and 1382 in group 3. The demographic analysis showed that patients in group 1 had the worst preoperative renal function and, higher Euroscore 2 (3.9 (sd 3.8) vs group 2, 2.7 (sd 2.9) vs group 3, 1.9 (sd 1.8) p Discussion This large retrospective observational study comparing the impact of different haemoglobin nadir within 4 days after cardiac surgery on morbidity and mortality showed a worsening in outcomes for haemoglobin values under 80g/L.