Preoperative hemostatic testing and the risk of postoperative bleeding in coronary artery bypass surgery patients.

BACKGROUND: We sought to assess predictability of excessive bleeding using thrombelastography (TEG), multiplate impedance aggregometry, and conventional coagulation tests including fibrinogen in patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: A total of 170 patients were enrolled in this prospective observational study. TEG, Multiplate aggregometry, and coagulation tests were sampled on the day before surgery. Excessive bleeding was defined as >1000 mL over 18 hours. RESULTS: Multiplate-adenosine diphosphate (ADP) measurements were significantly lower in patients with excessive bleeding, 85.5AU +/- 32.8 versus 108.5AU +/- 30.0, p = 0.012. Bivariate analysis revealed body mass index, myocardial infarction, and multiplate-ADP as predictors of bleeding. In multivariable linear regression analysis, multiplate-ADP remained a significant predictor of bleeding (beta: -6.2 [confidence interval: -12.0 to -0.3], p = 0.035). The lowest interval of multiplate-ADP (<50 AUC) was associated with significantly more bleeding and need for platelet concentrate transfusion. Fibrinogen levels <2.5 g/L were also found to be associated with excess bleeding (p = 0.020). CONCLUSIONS: Multiplate impedance aggregometry identified patients at risk for excessive bleeding after CABG. Low fibrinogen levels were associated with increased bleeding. Neither routine TEG parameters nor conventional coagulation tests were correlated with bleeding.