An Optimal Window of Platelet Reactivity by LTA Assay for Patients Undergoing Percutaneous Coronary Intervention

Abstract Objective This study was aimed to investigate an optimal therapeutic window for platelet reactivity (PR) to predict the lowest ischemic and bleeding events in patients underwent percutaneous coronary intervention (PCI) and treated with dual antiplatelet agents. Design A total of 1709 patients who had received coronary stent implantation and had taken aspirin 100 mg in combination with clopidogrel 75 mg daily for >5 days were consecutively recruited and their platelet reactivity was determined by light transmittance aggregometry (LTA). All patients were followed up for 12 months. The primary end-point was the net adverse clinical events (NACE) of cardiovascular death, nonfatal myocardial infarction (MI), target vessel revascularization (TVR) , stent thrombosis (ST) and any bleeding.Result By using the receiver-operating curve (ROC) analysis, the optimal cutoff values were found to be 37.5% and 25.5% respectively in predicting ischemic and bleeding events. Patients were classified into 2 groups according to PR: inside the window group (IW) [adenosine diphosphate (ADP) induced platelet aggregation (PLADP) 25.5%-37.4%)] and outside the window group (OW) (PLADP <25.5% or ≥37.5%). The incidence of NACE was 16.8% and 23.1% respectively in the IW and OW group. The hazard ratio of NACE in IW-group was significantly lower [0.69 (95% CI: 0.54–0.89; P = 0.004)] than that in the OW-group during 12 month follow-up. Conclusion An optimal therapeutic window of 25.5%-37.4% for PLADP predicts the lowest risk of NACE, which could be referred for tailored antiplatelet treatment while using LTA assay. Trial and clinical registry Trial registration number: ClinicalTrials.gov NCT01968499. Registered 18 October 2013 - Retrospectively registered.