Long-term Antiplatelet Therapy After Coronary Artery Bypass Grafting: Time to Reconsider Clopidogrel as the Default Monotherapy

Antiplatelet therapy remains a cornerstone of secondary prevention in coronary artery disease (CAD).Although antiplatelet strategies following percutaneous coronary intervention (PCI) have been well established through numerous large-scale clinical trials, the optimal antiplatelet strategy after coronary artery bypass grafting (CABG) remains less clearly defined because of the limited availability of robust clinical evidence.1) Guideline recommendations for antithrombotic therapy in CABG patients are frequently extrapolated from studies of CAD patients who were treated with medical therapy or underwent PCI.2)3) Extrapolating data from non-surgical populations to post-CABG patients may be inappropriate because CABG patients have distinct clinical risk profiles and undergo revascularization through fundamentally different mechanisms than PCI.In addition, bypass graft disease follows unique pathophysiological pathways compared with native coronary artery disease, further limiting the applicability of PCI-derived evidence.1) Establishing antithrombotic therapy after CABG requires balancing ischemic and bleeding risks to maximize net clinical benefit and facilitate shared decision-making between clinicians and patients.Most CABG patients have received single antiplatelet therapy (SAPT) with low-dose aspirin, which long-term use is appropriate to reduce the risk of ischemic events and graft occlusion.1) In the PCI setting, bleeding risk exerts a greater impact than ischemic risk on the net clinical benefit associated with the intensity and duration of dual antiplatelet therapy (DAPT). 4)A recent guideline recommends 12 months of DAPT with aspirin and a P2Y 12 inhibitor as the standard antithrombotic strategy in CABG patients who are not at high bleeding risk (HBR), regardless of the clinical presentation.1) However, evidence supporting the clinical benefit of DAPT after CABG in patients with CAD remains limited, particularly beyond 1 year after surgery.In patients undergoing CABG for CAD, the use of DAPT may be more appropriately guided by its potential effect on graft patency.[5][6][7][8] Patent CABG grafts restore distal coronary blood flow and protect against spontaneous myocardial infarction arising from proximal plaque rupture and thrombosis.Accordingly, graft failure may be strongly associated with adverse cardiac events and mortality after CABG.[5][6][7][8]