Single vs double antiplatelet therapy in acute coronary syndrome: Predictors of bleeding after coronary artery bypass grafting

AIM:To investigate the contribution of anti-platelet therapy and derangements of pre-operative classical coagulation and thromboelastometry parameters to major bleeding post-coronary artery bypass grafting(CABG).METHODS:Two groups of CABG patients were studied:Group A,treated with aspirin alone(n=50),and Group B treated with aspirin and clopidogrel(n=50).Both had similar preoperative,clinical,biologic characteristics and operative management.Classic coagulation parameters and rotational thromboelastometry(ROTEM)profiles were determined preoperatively for both groups and the same heparin treatment was administered.ROTEM profiles(INTEM and EXTEM assays)were analyzed,both for traditional parameters,and thrombin generation potential,expressed by area-under-curve(AUC).RESULTS:There was no significant difference betweenrates of major bleeding between patients treated with aspirin alone,compared with those treated with aspirin and clopidogrel(12%vs 16%,P=0.77).In the 14 cases of major bleeding,pre-operative classic coagulation and traditional ROTEM parameters were comparable.Conversely we observed that the AUC in the EXTEM test was significantly lower in bleeders(5030±1115 Ohm*min)than non-bleeders(6568±548Ohm*min)(P<0.0001).CONCLUSION:We observed that patients with a low AUC value were at a significantly higher risk of bleeding compared to patients with higher AUC,regardless of antiplatelet treatment.This suggests that thrombin generation potential,irrespective of the degree of platelet inhibition,correlates with surgical bleeding.