Reduced Effect of Aspirin and Clopidogrel Following Hybrid Coronary Revascularization

OBJECTIVE: Reduced effect of antiplatelet therapy following coronary artery bypass grafting is associated with reduced graft patency. We sought to evaluate the impact of hybrid coronary revascularization on the effect of aspirin and clopidogrel and whether high baseline platelet aggregation, high postoperative levels of platelet turnover, and acute-phase response may contribute to the effect. METHODS: We prospectively studied platelet aggregation (VerifyNow and Multiplate Analyzer), platelet turnover (immature platelets, mean platelet volume, and thrombopoietin), and acute-phase reactants (C-reactive protein, von Willebrand factor, and coagulation factor VIII) in 40 patients undergoing elective hybrid coronary revascularization (off-pump surgical revascularization through J-hemisternotomy followed by percutaneous coronary intervention [PCI]). Preoperative blood samples on- and off-aspirin were compared with blood samples obtained postoperatively, following PCI when dual antiplatelet therapy had been initiated and at 1-year follow-up. RESULTS: The antiplatelet effect of aspirin was significantly reduced in the early postoperative period as measured by VerifyNow Aspirin but not by Multiplate ASPI test. The antiplatelet effect of clopidogrel was significantly reduced following PCI as measured by VerifyNow P2Y12 and Multiplate ADP test. The level of baseline aggregation did not predict the antiplatelet effect of aspirin or clopidogrel, and no association was found between platelet aggregation and postoperative platelet turnover or acute-phase reaction. CONCLUSIONS: A transient reduction in the antiplatelet effect of aspirin and clopidogrel was observed after hybrid coronary revascularization despite limited surgical trauma and off-pump technique. Neither baseline platelet aggregation nor postoperatively increased platelet turnover and acute-phase response could explain this finding. ClinicalTrials.gov identifier, NCT02293928.