Participants being treated with a maintenance dose of 75 mg clopidogrel and 100 mg aspirin daily after previous PCI with coronary stenting were included in the study. Participants were randomly assigned to either the pantoprazole 40 mg once-daily group or the ranitidine 150 mg twice-daily group using a computer-generated randomized table. An independent investigator generated the random allocation sequence. Blood samples were collected at 9:00 on day prior to treatment (day 0) and on day 9. Measuring impedance was performed by one independent investigator in a blinded manner.