Platelet aggregation inhibitor given^preoperative:Prid:Pt:^Patient:Nom
platelet aggregation inhibitor given^preoperative:prid:pt:^patient:nom
Platelet aggregation inhibitor given^preoperative:Presence or Identity:To identify measures at a point in time:^Patient:Nominal
platelet aggregation inhibitor given^preoperative:presence or identity:to identify measures at a point in time:^patient:nominal