Clopidogrel responsiveness regardless of discontinuation date predicts increased blood loss and transfusion requirement following off-pump coronary bypass surgery

Abstract

[한글]

[영문]Introduction: Interindividual variability of clopidogrel responsiveness, rather than the proximity to surgery, may influence bleeding and transfusion requirement. The objective of this study was to evaluate the association of % platelet inhibitory response to clopidogrel assessed by modified thromboelastography (TEG) with bleeding and transfusion requirement following off-pump coronary bypass surgery (OPCAB).Materials and methods: One hundred patients receiving clopidogrel within 5 days of OPCAB were prospectively enrolled. Primary endpoint was to compare postoperative bleeding and transfusion requirement in relation to tertile distribution of % platelet inhibitory responses to clopidogrel.Results: Blood loss of the patients in the third tertile was 914 ± 264 ml versus 623 ± 249 ml in the first and 683 ± 254 ml in the second tertile (p = 0.001). Significantly more patients in the third tertile were transfused and the number of units transfused was also larger. On multivariate analysis, % platelet inhibitory response to clopidogrel in the third tertile was associated with 11-fold increased risk of transfusion (95% confidence interval: 2.77 to 47.30, p = 0.001). By receiver operating characteristics curve analysis, the optimal cut-off value for transfusion was 70% platelet inhibitory response to clopidogrel (area under the curve: 0.771; 95% confidence interval: 0.674 to 0.868, p <0.001).Conclusions: Regardless of the proximity of clopidogrel exposure, patients exhibiting % platelet inhibitory response to clopidogrel < 70% may safely undergo OPCAB without increased risk of transfusion requirement. TEG platelet mapping assay might be useful in providing an objective guide to decide the timing of OPCAB in patients who are in need for continued antiplatelet therapy.