Recurrence of Acute Myocardial Infarction in Patients Discharged on Clopidogrel and a Proton Pump Inhibitor After Stent Placement for Acute Myocardial Infarction

Background: The purpose of this study was to determine the readmission rate for acute myocardial infarction (AMI) in patients discharged on clopidogrel and a proton-pump inhibitor (PPI) versus patients discharged on clopidogrel alone after experiencing an AMI and undergoing stent placement. Clopidogrel is a prodrug that requires metabolism in the liver by the cytochrome P450 system (CYP450), in particular cytochrome P450 2C19 (CYP2C19).(1) Recent studies have suggested that medications metabolized by CYP450, such as PPIs, influence the effect of clopidogrel on platelet function(2,3) with an increased risk of cardiovascular events.(4,5) PPIs are often administered with clopidogrel due to the increased bleeding risk of dual antiplatelet therapy, a strategy endorsed by existing consensus guidelines.(6) Hypothesis: Treatment with a PPI in combination with clopidogrel would increase the risk of readmission for an AMI after stent placement for AMI. Methods: We collected data on all patients discharged on clopidogrel after stent placement for an AMI between January 2003 and January 2008. Patients were followed for 1 year after their index hospitalization for readmission for an AMI. Rates of readmission were determined for those discharged on clopidogrel alone versus those discharged on clopidogrel and a PPI. Results: Patients discharged on clopidogrel and a PPI had higher rates of readmission for AMI within 1 year of stent implantation for AMI. Conclusions: Patients discharged on clopidogrel and a PPI, including esomeprazole and pantoprazole, seem to be at an increased risk of recurrent AMI within 1 year after stent placement for an AMI.