Effects of pre-hospital clopidogrel administration on early and late residual platelet reactivity in ST-segment elevation myocardial infarction patients undergoing primary intervention

The results of our observational study can be summarized as follows:1) The pre-hospital administration of clopidogrel in STEMI patients resulted in a negligible level of platelet inhibition and as a consequence in high residual on-treatment platelet reactivity at the time of intervention in the great majority of patients at the time of intervention; 2) Patients receiving a 600 mg clopidogrel loading dose did not show an improved platelet profile in terms of %IPA or residual PRU levels as compared with those receiving a 300 mg regimen at the time of intervention; 3) The proportion of patients with residual high on-treatment platelet reactivity fell from 86% at the time of intervention to 11% at 1 month.