Optimal Switching Antiplatelet Regimen in Patients with Ticagrelor to a Thienopyridine in Korean Patients (SWAPT-K Study)

BackgroundDual antiplatelet therapy (DAPT) with aspirin and potent P2Y₁₂ inhibitors such as ticagrelor effectively reduces ischemic events but increases bleeding risk. In patients requiring long-term DAPT, switching from ticagrelor to a thienopyridine is often considered to reduce bleeding risk or address other clinical concerns. However, such switching may cause a transient reduction in platelet inhibition, raising concerns about thrombotic complications. In particular, evidence is limited regarding the optimal loading dose strategy for East Asian patients undergoing this transition.MethodsIn this randomized, open-label trial, 43 patients with acute coronary syndrome (ACS) who had received ticagrelor-based DAPT for > 6 months after stent implantation were randomized to clopidogrel 600 mg loading/75 mg maintenance, clopidogrel 300 mg loading/75 mg maintenance, or prasugrel 30 mg loading/5 mg maintenance. Platelet reactivity and inflammatory markers (MMP-2, MMP-9, TNF-α) were assessed at baseline, 48 h, and 5 days after switching. The primary endpoint was the proportion of patients achieving optimal platelet reactivity (OPR).ResultsThe proportion of patients achieving OPR was similar among groups at baseline (p = 0.483), 48 h (p = 0.699), and 5 days (p = 0.729). No significant intergroup differences were observed in inflammatory marker levels at any time point. No major adverse cardiovascular events occurred during follow-up.ConclusionsIn stable ACS patients on long-term DAPT, switching from ticagrelor to either clopidogrel or prasugrel maintained consistent platelet inhibition and inflammatory profiles, indicating that these switching strategies produce comparable pharmacodynamic profiles in East Asian populations during the early post-switch period.Trial RegistrationThis investigator-initiated pharmacodynamic study was not prospectively registered.