Point‐of‐Care Platelet Function Testing Predicts Bleeding in Patients Exposed to Clopidogrel Undergoing Coronary Artery Bypass Grafting: Verify Pre‐Op TIMI 45—A Pilot Study

Background Guidelines recommend delaying coronary artery bypass grafting ( CABG ) for 5 days after discontinuing clopidogrel. However, platelet function may recover quicker in certain individuals. Hypothesis We hypothesized that perioperative measurement of platelet function with a point‐of‐care P2Y 12 inhibitor assay could predict bleeding during CABG in patients exposed to clopidogrel. Methods Verify Pre‐Op TIMI 45 was a prospective pilot study of 39 patients on clopidogrel who subsequently underwent CABG . Preoperative on‐treatment platelet reactivity was assessed with VerifyNow P2Y 12 Reaction Units ( PRU ), with higher PRU indicating more reactive platelets. Outcomes were stratified by PRU quartiles, as well as prespecified cutpoints for the lowest quartile ( PRU 173), a cutpoint for major bleeding determined by the Youden index using receiver operator curve analysis ( PRU 207), and clopidogrel resistance ( PRU 230). Results Patients in higher PRU quartiles experienced smaller decreases in hemoglobin and hematocrit ( P  < 0.05 for all comparisons), less major bleeding ( P  = 0.021), and less major or minor bleeding ( P  = 0.003). Patients above the PRU 207 and 230 cutpoints had less chest‐tube output ( P  = 0.041 and P  = 0.012, respectively), less major bleeding ( P  = 0.005 and P  = 0.036, respectively), and less major or minor bleeding ( P  = 0.013 and P  < 0.001, respectively). By receiver operator curve analysis, preoperative PRU  ≤ 207 discriminated between patients with and without major bleeding during surgery (area under the curve: 0.76, 95% confidence interval: 0.59‐0.94, P  = 0.018). Conclusions In this pilot study, we found that point‐of‐care platelet function assessment could predict bleeding in patients recently exposed to clopidogrel undergoing CABG .