Objective: The aim of the present study was to assess the early clinical outcome and risk factors in old patients with acute ST elevation myocardial infarction (STEMI) following primary percutaneous coronary intervention (PCI). Methods: A total of 136 patients older than 60 years with STEMI who received successful PCI were included in this study. The patients were classified in 2 age groups: patients ≥75 years and <75 years of age. The extent of coronary artery lesions was measured by quantitative coronary artery angiography (QCA). Subjects were tracked for subsequent cardiovascular events: cardiac death, myocardial infarction, heart failure, percutaneous coronary intervention, coronary artery bypass and stroke. Results: Though the older group had a higher prevalence of adverse baseline characteristics and lower final TIMI flow than patients<75y (P<0.05), the procedural success did not make difference between the two groups. In 12 months follow-up of 136 study participants, there occurred 39 CV events : cardiac death (five patients), heart failure (nineteen patients), and stroke (six patients). Three patients received coronary bypass grafts and six patients underwent PCI. Heart failure and overall cardiovascular event rates were higher in older patients compared with those in patients<75y. The main adverse clinical events (MACE) for the old group were a little higher comparing with the younger in 12-month follow-up (P=0.029 6 and P=0.043 4). Multivariate cox analysis identified that a diagnosis of diabetes (HR 2.495, 95%CI 1.224 to 5.083, P= 0.011 8) and time from symptom(HR 1.450, 95%CI 1.143 to 1.841, P= 0.008 2) to PCI as independent predictors of CV events after adjustment of all entered baseline variables. Conclusion: Our study suggests that drug-eluting stent implantation in older patients with acute ST elevation myocardial infarction has high initial procedural success rates despite having more severe baseline risk characteristics, and to shorten the time from symptom onset to PCI may decrease cardiovascular events in old patients following PCI. Objective: The aim of the present study was to assess the early clinical outcome and risk factors in old patients with acute ST elevation myocardial infarction (STEMI) following primary percutaneous coronary intervention (PCI). Methods: A total of 136 patients older than 60 years with STEMI who received successful PCI were included in this study. The patients were classified in 2 age groups: patients ≥75 years and <75 years of age. The extent of coronary artery lesions was measured by quantitative coronary artery angiography (QCA). Subjects were tracked for consecutive cardiovascular events: cardiac death, myocardial infarction, heart failure, percutaneous coronary intervention, coronary artery bypass and stroke. P <0.05), the procedural success did not make difference between the two groups. In 12 months follow-up of 136 study participants, there occ Three patients received coronary bypass grafts and six patients underwent PCI. Heart failure and overall cardiovascular event rates were higher in older patients compared with those in patients <75y. The main adverse clinical events (MACE) for the old group were a little higher comparing with the younger in 12-month follow-up (P = 0.0296 and P = 0.043 4). Multivariate cox analysis identified that a diagnosis of diabetes (HR 2.495, 95% CI 1.224 to 5.083, P = 0.011 8) and time from symptom (HR 1.450, 95% CI 1.143 to 1.841, P = 0.008 2) to PCI as independent predictors of CV events after adjustment of all entered baseline variables. Conclusion: Our study suggests that drug-eluting stent implantation in older patients with acute ST elevation myocardial infarction has high initial procedural success rates despite having more severe baseline risk characteristics, and to shorten the time f rom symptom onset to PCI may decrease cardiovascular events in old patients following PCI