Does thromboelastography predict bleeding in patients treated with clopidogrel or ticagrelor in off-pump coronary artery bypass grafting?

Objectives: We sought to investigate the predictive value of platelet function assessment for bleeding in clopi dogrel-or ticagrelor-treated patients undergoing off-pump coronary artery bypass grafting (OPCABG).Methods: This prospective study included patients treated with acetylsalicylic acid and clopidogrel or acetylsalicylic acid and ticagrelor and scheduled for OPCABG. The percentage of platelet aggregation was evaluated by thromboelastography. Postoperative blood loss was measured as the chest tube drainage (CTD) and excessive blood loss was settled as CTD with more than 600 mL at first postoperative 12 h. Major bleeding complications were defined by Bleeding Academic Research Consortium (BARC) type 4-CABG related bleeding or class 3 or class 4 bleeding in universal definition of perioperative bleeding (UDPB) in adult cardiac surgery.Results: A total of 434 consecutive patients were included. There was a negative correlation (r =-0.133, P = 0.0056) between ADP-induced platelet aggregation and CTD at 12 h. The platelet aggregation exhibited a moderate performance (AUC = 0.616) for predicting excessive postoperative blood loss. Multivariable analysis showed that ADP-induced platelet aggregation < 33.45% (OR = 2.976, 95% CI: 1.325-6.711, P = 0.008) was independently associated with excessive postoperative blood loss. However, the percentage of ADP-induced platelet aggregation predicted neither UDPB-defined nor BARC-defined major bleeding. Instead, P2Y12 receptor antagonist discontinuation time was independently related to the risk of major bleeding complication.Conclusions: ADP-induced platelet aggregation detected by thromboelastography was negatively related to postoperative blood loss and platelet aggregation < 33.45% was associated with excessive postoperative blood loss. However, platelet function assessment by thromboelastography failed to predict major bleeding complications.