Chronic kidney disease (CKD) is associated with an increased risk of acute coronary syndrome (ACS) and cardiovascular death. CKD patients suffering from ACS are exposed to an increased risk of thrombotic recurrences and a higher bleeding rate than patients with normal renal function. However, CKD patients are excluded or underrepresented in clinical trials. Therefore, determining the optimal antiplatelet strategy in this population is of utmost importance. We designed the TicagRelor Or Clopidogrel in severe or terminal chronic kidney patients Undergoing PERcutaneous coronary intervention for acute coronary syndrome (TROUPER) trial: a prospective, controlled, multicenter, randomized trial to investigate the optimal P2Y12 antagonist in CKD patients with ACS. Patients with stage ≥3b CKD are eligible if the diagnosis of ACS is made and invasive strategy scheduled. Patients are randomized 1:1 between a control group with a 600-mg loading dose of clopidogrel followed by a 75-mg/d maintenance dose for 1 year and an experimental group with a 180-mg loading dose of ticagrelor followed by a 90-mg twice daily maintenance dose for the same duration. The primary end point is defined by the rate of major adverse cardiovascular events, including death, myocardial infarction, urgent revascularization, and stroke at 1 year. Safety will be evaluated by the bleeding rate (Bleeding Academic Research Consortium). To demonstrate the superiority of ticagrelor on major adverse cardiovascular events, we calculated that 508 patients are required. The aim of the TROUPER trial is to compare the efficacy of ticagrelor and clopidogrel in stage >3b CKD patients presenting with ACS and scheduled for an invasive strategy. RCT# NCT03357874.Copyright © 2020 Elsevier Inc. All rights reserved.