Response to Letter Regarding Article, “Platelet Function Measurement-Based Strategy to Reduce Bleeding and Waiting Time in Clopidogrel-Treated Patients Undergoing Coronary Artery Bypass Graft Surgery: The Timing Based on Platelet Function Strategy to Reduce Clopidogrel-Associated Bleeding Related to CABG (TARGET-CABG) Study”

We thank Drs. Petricevic and Biocina for their interest in Timing Based on Platelet Function Strategy to Reduce Clopidogrel-Associated Bleeding Related to Coronary Artery Bypass Graft (TARGET-CABG) study. Aspirin maintenance dose was a clinical decision. Our previous observations of uniform and near-complete inhibition of platelet cyclooxygenase-1 activity as measured by arachidonic acid-induced platelet aggregation at 81 mg to 325 mg daily aspirin doses question the clinical utility of this test. 1 Current Society of Thoratic Surgeons Blood Conservation Guidelines recommend against preoperative discontinuation of aspirin except in purely elective patients without acute coronary syndrome. 2 There is inconsistent evidence of increased bleeding associated with preoperative aspirin, particularly with doses 325 mg. 3 However, in patients receiving dual antiplatelet therapy, thienopyridine-induced platelet inhibition seems much more relevant. he TARGET-CABG Study used a standardized perioperative management and ANCOVA was performed to correct for confounders, thereby considering doses of aspirin and other perioperative variables known to affect bleeding. A mere correlation between chest tube drainage and aspirin response, as suggested by Petricevic and Biocina, would provide a univariate approach.