RESUMO
BACKGROUND: Evidence to support immediate P2Y12 inhibitor loading in ST-segment elevation myocardial infarction (STEMI) is limited. OBJECTIVES: This study sought to compare outcomes of STEMI patients receiving immediate or delayed P2Y12 inhibitor treatment. METHODS: Using data from the prospective Bern-PCI registry between 2016 and 2020, we stratified STEMI patients undergoing percutaneous coronary intervention according to time periods with different institutional recommendations regarding P2Y12 inhibitor pretreatment. In cohort 1 (October 2016-September 2018), immediate P2Y12 inhibitor treatment was recommended. In cohort 2 (October 2018-September 2020), P2Y12 inhibitor treatment was recommended after coronary anatomy was confirmed. The primary endpoint was a composite of major adverse cardiac or cerebrovascular events (MACCEs) defined as all-cause death, recurrent myocardial infarction, stroke, or definite stent thrombosis at 30 days. Sensitivity analysis included only patients in whom these recommendations were followed. RESULTS: Cohort 1 included 1,116 patients; pretreatment was actually given in 708 (63.4%). Cohort 2 included 847 patients; pretreatment was withheld in 798 (94.2%). The mean age was 65 ± 13 years, and 24% were female. Baseline characteristics were well-balanced between groups. The median difference for P2Y12 loading to angiography was 52 minutes between cohort 1 and 2 and 100 minutes between patients receiving vs not receiving pretreatment. Rates of MACCEs were similar between cohort 1 and cohort 2 (10.1% vs 8.1%; adjusted HR: 0.91; 95% CI: 0.65-1.28; P = 0.59) and between patients receiving vs not receiving pretreatment (7.1% vs 8.4%; adjusted HR: 1.17; 95% CI: 0.78-1.74; P = 0.45). CONCLUSIONS: In this cohort study of patients with STEMI undergoing primary percutaneous coronary intervention, P2Y12 inhibitor pretreatment was not associated with improved MACCEs.