Clopidogrel low response is associated with a significantly higher risk for ischemic complications after percutaneous coronary intervention. Ticagrelor and prasugrel are more potent platelet inhibitory drugs and both have been shown to significantly reduce ischemic events as compared to clopidogrel. No direct comparison between ticagrelor and prasugrel in terms of their antiplatelet efficacy exists. The aim of this study is to assess the antiplatelet treatment efficacy of ticagrelor versus prasugrel over time in confirmed clopidogrel low responders undergoing percutaneous coronary intervention.