Abstract 15369: Impact of Switching Prasugrel to Clopidogrel on Platelet Inhibition and Clinical Outcomes
BACKGROUND: Many acute coronary syndrome (ACS) patients are switched from prasugrel to clopidogrel within the first year of treatment. AIM: To assess the consequence of switching from prasugrel to clopidogrel on platelet inhibition and clinical outcomes.
METHODS: Platelet reactivity was prospectively evaluated using the VerifyNow P2Y12 assay in a cohort of 300 ACS patients treated by a maintenance dose of prasugrel 10 mg. Patients at high risk of bleeding and/or with high level of platelet inhibition (HPI, PRU<30) were switched to clopidogrel 75 mg and platelet reactivity was reassessed 1 month later. High on-treatment platelet reactivity (HPR) was defined as PRU>208. Bleeding events defined according to the BARC classification and ischemic events were collected at 1 month.
RESULTS: Our population was a high-risk ACS population including two thirds of patients with ST segment elevation myocardial infarction. The other patients were mainly diabetic patients who presented with non ST-elevation myocardial infarction. A group of 31 patients (10.3%) was switched to clopidogrel 75mg of whom 29 (93.5%) had initially HPI. This led to a 10-fold increase in the PRU level (14±4 to 155±15, p=0.0001) and a 6-fold increase in the rate of HPR, from 4.8% in those who remained on prasugrel (n=13/269) versus 29% in those switched to clopidogrel (n=9/31). No major bleeding was reported in our population, but 20.3 % of patients reported minor bleeding mainly BARC 1 bleeding (17.1%). Patients who were switched to clopidogrel had a lower bleeding rate (BARC 1 and 2) than those that remained on prasugrel (9.7 % vs. 32.2%, p = 0.03) (Fig1). There was no ischemic event reported at one month follow-up.
CONCLUSION: Switching from prasugrel 10 mg to clopidogrel 75 mg exposes patients to significant increased risk of HPR with potentially less ischemic protection and to a significant reduction in minor bleeding at one month.
- © 2012 by American Heart Association, Inc.