Prospective Evaluation of On-Clopidogrel Platelet Reactivity Over Time in Patients Treated With Percutaneous Coronary Intervention Relationship With Gene Polymorphisms and Clinical Outcome

ObjectivesThis study sought to investigate the evolving pattern over time of on-clopidogrel platelet reactivity (PR) and its relationship with genotype and clinical outcomes after percutaneous coronary intervention.BackgroundWhether on-clopidogrel PR and role of genotype differ over time is unknown.MethodsOn-clopidogrel PR before percutaneous coronary intervention, and 1 and 6 months thereafter via VerifyNow P2Y12 (Accumetrics Inc., San Diego, California), CYP2C19*2, *17, CYP3A5*3, and ABCB1 polymorphisms were evaluated in 300 patients. Death, stroke, myocardial infarction, and bleedings were assessed up to 1 year.ResultsOn-clopidogrel PR varied significantly over time, being higher at baseline than at 1 and 6 months after. From baseline to 1 month, 83 of 300 patients varied their response status. This was mainly due to baseline poor responders becoming full responders (75 of 83). Genotype justifies roughly 18% of this trend. CYP2C19*2 and *17 influence on PR was consistent over time, whereas that of ABCB1 appeared of greater impact at baseline. On-clopidogrel PR at 1 month independently best predicts ischemic and bleeding events. We found a therapeutic window (86 to 238 P2Y12 reactivity units) with a lower incidence of both ischemic and bleeding complications. A risk score was created by combining genotype (ABCB1 and CYP2C19*2), baseline PR, and creatinine clearance to predict 1-month poor responsiveness and 1-year poor prognosis.ConclusionsIn patients at steady state for clopidogrel undergoing percutaneous coronary intervention, PR decreases from baseline to 1 month. Genotype influences ≈18% of this trend. On-clopidogrel PR at 1 month is the strongest predictor of adverse outcomes, and this can be predicted by combining genotype to baseline phenotype and clinical variables