text: The importance of this issue is reflected in reports estimating the frequency of clopidogrel nonresponders at about 10% and low responders at about 20%.(44) Among patients identified as clopidogrel responders, switching from clopidogrel to ticagrelor resulted in a mean IPA increase of 26%, whereas switching from ticagrelor to clopidogrel resulted in a mean IPA decrease of 24%.