Abstract 528: Correlation Between Expression Level of Platelet Endothelial Aggregation Receptor 1 and On-aspirin Platelet Aggregation

Abstract

Background: Aspirin is a basilar support in coronary heart disease secondary prevention, patients with high platelet aggregation during aspirin therapy after percutaneous coronary intervention(PCI) may lead to increased risk of ischemic vascular events. Platelet endothelial aggregation receptor 1(PEAR1) is a platelet transmembrane protein which reported play an important role in platelet aggregation. The aim of the study is to analyze the correlation between PEAR1 expression level and on-aspirin platelet aggregation. Methods: Consecutive patients with acute myocardial infarction after PCI under dual antiplatelet with aspirin and clopidogrel were enrolled in the cohort. Blood samples were obtained 3 days after PCI by peripheral venipuncture. On-aspirin platelet aggregation was assessed by VerifyNow Aspirin Assay, results were recorded as aspirin reaction unit(ARU). Expression of PEAR1 on platelet membrane was determined by washed platelet incubated with mouse anti-human PEAR1 phycoerythrin(PE)-conjugated monoclonal antibody for 20 minutes and analyzed by flow cytometry, results were recorded as mean fluorescence intensity(MFI). Results: A total of 131 patients were enrolled in the study, the average age was 59.88±10.84 years, the average ARU was 443.21±65.99, the median MFI was 137.00(interquartile range 105.00 to 226.00). Patients with high platelet aggregation(ARU>550) showed higher expression of PEAR1 on the surface of platelet than those with low platelet aggregation(ARU<400), although did not achieve a significant difference [129.00(interquartile range 116.75 to 215.75) vs 116.00(interquartile range 86.05 to 197.50), P=0.11]. The expression level of PEAR1 showed a poorly positive correlation with platelet aggregation(Spearman r s =0.21, p=0.02). Conclusion: The study showed that elevated expression of PEAR1 was weakly related to increased on-aspirin platelet aggregation after PCI.