AbstractBackgroundPotent P2Y12 inhibitors are recommended for up to 12 months after percutaneous coronary intervention (PCI) in patients diagnosed with acute coronary syndrome (ACS). However, the prescription pattern is diverse in real world practice, which includes various switching between antiplatelet regimens. In this study, we analyzed the prescription patterns of prasugrel, and assessed the safety and effectiveness of P2Y12 inhibitors switching patterns in a real world registry of patients subjected to PCI after ACS.MethodsThe EFF-K study included 3077 ACS patients receiving prasugrel-based dual antiplatelet therapy. The cohort was divided into those who were administered with prasugrel as the primary antiplatelet treatment (naïve cohort) or as a substitute agent after clopidogrel or ticagrelor pre-treatment (switch cohort). The primary endpoint was a net adverse clinical event (NACE; a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, or TIMI major bleeding unrelated to coronary-artery bypass grafting).ResultsA total of 3077 patients diagnosed with ACS were included in the analysis. Among the total population, 726 patients (23.6%) were classed as the naïve cohort and 2351 patients (76.4%) as the switch cohort. Baseline characteristics showed that the switch cohort had more comorbidities, such as hypertension, diabetes mellitus, heart failure and previous PCI. The major cause of switching to prasugrel in the switch cohort was the necessity for a more potent antiplatelet agent (56.3%). During a 12-month follow-up period, 51 patients (1.7%) experienced at least one NACE. The incidence of NACE did not differ between the naïve and switch cohort (1.5% vs. 1.7%, Hazard ratio 1.17, 95% Confidence interval 0.56–2.43, P = 0.677). In subgroup analysis, no significant interaction was observed between the treatment strategy and the incidence of NACE across various subgroups.ConclusionsDual antiplatelet therapy with prasugrel seems to be safe and effective both as a primary treatment and as a substitute for other P2Y12 inhibitors in a real world registry of Asian ACS patients receiving PCI.Trial registration: KCT0002356, registered June 13, 2017.