Background: Both abnormal coronary flow reserve (CFR) following percutaneous coronary intervention (PCI) and elevated white blood cell (WBC) count in acute myocardial infarction (AMI) are known as useful predictors for adverse outcomes. We evaluated the value of abnormal CFR and WBC count for prediction of adverse outcomes in AMI patients following PCI. Methods: We studied 245 consecutive patients (mean age 56짹12, male 195) presenting with AMI who were admitted to our institution. Analyze of CFR and hyperemia microvascular resistance index (MVRI) was performed following PCI by intra-coronary Doppler wire. WBC count was obtained at admission and pre-and post-PCI. The occurrence of major adverse cardiac events (MACE) were analyzed during clinical follow up (19.7짹7.1 months). According to the best cutoff value of the CFR and WBC count for predicting MACE, the patients were divided into 4 groups: group A, CFR<1.4 with WBC count���10.4x109/L; group B, CFR<1.4 with WBC count>10.4x109/L; group C, CFR���1.4 with WBC count���10.4x109/L; group D, CFR���1.4 with WBC count>10.4x109/L. Results: A decreased CFR was associated with an increased WBC count (r=0.145, p=0.024) and an increased MVRI (r=-0.396, p<0.001). An increased WBC count was associated with an increased peak creatine kinase value (r=0.387, p<0.001). The mortality rate was significantly higher in group B (12.96%, p<0.001) than other groups. See the table. Conclusion: Abnormal CFR following PCI with elevation of WBC count in patients with AMI were associated with a higher incidence of adverse long-term clinical outcomes. This observation may provide a potential explanation that links of microvascular dysfunction and vascular inflammation in patients with AMI.