Abstract 4772: Preoperative Anemia in Patients Undergoing Coronary Artery Bypass Grafting Predicts Acute Kidney Injury
OBJECTIVE Recent authoritative studies suggested that low preoperative haemoglobin concentration may affect cardiac surgery outcomes. This study aimed to investigate whether preoperative anaemia is an independent determinant of adverse events after CABG.
METHODS This single centre prospective study investigated 1214 consecutive patients undergoing CABG between January 2004 and June 2007, collecting 100 variables per patient. In 1047 patients (median age 64, 18.8% female, 38.9% diabetics, 31.9% urgent/emergent, 15.3% with low preoperative LVEF) who underwent on pump procedures and received no preoperative transfusion, the prevalence of preoperative anaemia (according to World Health Organisation definition), and its unadjusted and adjusted relationships with in-hospital death, cardiac morbidity and acute kidney injury (RIFLE criteria) were obtained.
RESULTS The prevalence of preoperative anaemia was 28%. In-hospital death averaged 3.9%, cardiac morbidity 7.3 % and acute kidney injury 4 %. Unadjusted odds ratios for in-hospital death, cardiac morbidity and acute kidney injury were 3.8 (95% CI 2.0 –7.3), 1.7 (95% CI 1.1–2.8) and 4.0 (95% CI 2.1–7.6) respectively. Adjusting for confounders (including co-morbidities, surgical factors and blood transfusions) anaemia proved an independent predictor of acute kidney injury (OR 3.0; 95% confidence interval 1.5 to 6.0) whereas the cardiac morbidity and in-hospital mortality were independently predicted by postoperative kidney function.
CONCLUSIONS Preoperative anaemia is independently associated with acute kidney injury after CABG. Further studies are warranted to determine the impact of new preoperative risk stratification strategies and targeted therapeutic modalities on these outcomes.