Objectives: Based on previous studies with clopidogrel, the time between acute myocardial infarction (AMI) symptoms onset and primary percutaneous coronary intervention (PCI) was proven as important prognostic factor. Our aim was to assess the relationship between symptoms onset to needle time (SNT) and procedural results and the occurrence of ischemic endpoints in primary angioplasty patients treated with potent P2Y12 inhibitors. Methods: A total of 1,131 out of 1,230 patients randomized to the Prague-18 study (prasugrel vs. ticagrelor in primary PCI) were divided into a high and a low-risk group. The effect of defined SNT on patients' ischemic endpoints and prognosis by their risk status at admission was tested. Results: The median SNT was 3.2 hours. Longer SNTs resulted in a more frequent incidence of TIMI flow <3 post PCI (p=0.015). There were significant differences in the occurrence of the combined ischemic endpoint among the compared SNT groups at 30 days (p=0.032), and 1 year (p=0.011), with the highest incidence in the <<= 1 h SNT group of patients. "Latecomers" (SNT>4 hs) in the high-risk group experienced more reinfarction within 1 year [OR (95% CI) 3.23 (1.09-9.62) p=0.035]; no difference was found in the low-risk group. Conclusions: In the era of intense antithrombotic medication, stratification of MI patients undergoing primary angioplasty, based on initial ischemic risk assessment affected prognosis more than symptom onset to needle time. Longer time delay was significantly related to increased incidence of ischemic events and all-cause mortality only in patients with high ischemic risk. (C) 2021 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.