Ischemic events after percutaneous coronary intervention (PCI) remain a major concern for patients with coronary heart disease (CHD). The aim of the current study was to investigate whether thromboelastography (TEG) was a satisfactory technique to measure platelet function in vitro in order to improve risk stratification and the individual response to antiplatelet therapy. The diagnostic and prognostic utility of the maximum amplitude of adenosine diphosphate induced platelet-fibrin clots (MAADP) was measured with TEG in 759 patients undergoing elective PCI. A 600-mg dose of clopidogrel was taken more than 12 h before surgery in addition to a maintenance dose of aspirin 100 mg/day and clopidogrel 75 mg/day for 2 y. Platelet-fibrin clot strength was also measured in this study. An MAADP > 34 mm significantly predicted ischemic events after PCI, as indicated by an area under the curve (AUC) of 0.79 (95% CI: 0.72-0.87, P < 0.05) according to receiver operating characteristic (ROC) curve analysis. The multivariate Cox proportional hazards model identified MAADP > 34 mm and an FBG level > 7.0 mmol/L as significant independent predictors of first ischemic events at the 2-year time point (P < 0.05). With adequate clopidogrel pretreatment, patients who underwent elective PCI and who experienced ischemic events could be diagnosed with a certain MAADP according to TEG. TEG could be a good tool to measure platelet function.