Background:The relationship between obstructive sleep apnea (OSA) and platelet reactivity in patients undergoing percutaneous coronary intervention (PCI) has not been defined.The present prospective,single-center study explored the relationship between platelet reactivity and OSA in patients with PCI.Methods:A total of 242 patients were finally included in the study.OSA was screened ovight by polysomnography.Platelet reactivity was assessed with a sequential platelet counting method,and the platelet maximum aggregation ratio (MAR) and average aggregation ratio were calculated.All patients were assigned per apnea-hypopnea index (AHI) to non-OSA (n =128) and OSA (n =l 14) groups.The receiver operating characteristic curve analysis was used to evaluate the accuracy of AHI for high platelet reactivity (HPR) on aspirin and clopidogrel,and multivariable logistic regression was used to determine the independent predictors of HPR on aspirin and clopidogrel.Results:Median AHI was significantly higher in the OSA group than in the non-OSA group (34.5 events/h vs.8.1 events/h,Z =-13.422,P ＜ 0.001).Likewise,median arachidonic acid-and adenosine diphosphate-induced maximum aggregation rate (MAR) in the OSA group was significantly higher than those in the non-OSA group (21.1％ vs.17.7％,Z=-3.525,P ＜ 0.001 and 45.8％ vs.32.2％,Z =-5.708,P ＜ 0.001,respectively).Multivariable logistic regression showed that OSA was the only independent predictor for HPR on aspirin (odds ratio [OR]:1.055,95％ confidence interval [CI]:1.033-1.077,P ＜ 0.001) and clopidogrel (OR:1.036,95％ CI:1.017-1.056,P ＜ 0.001).The cutoffvalue of AHI for HPR on aspirin was 45.2 events/h (sensitivity 47.1％ and specificity 91.3％),whereas cutoffvalue of AHI for HPR on clopidogrel was 21.3 events/h (sensitivity 68.3％ and specificity 67.7％).Conclusion:Platelet reactivity appeared to be higher in OSA patients with PCI despite having received a loading dose of aspirin and clopidogrel,and OSA might be an independent predictor of HPR on aspirin and clopidogrel.