Background Percutaneous coronary intervention (PCI) is indicated for angina with coronary stenosis.However,PCI for asymptomatic coronary stenosis remains controversial.We prospectively followed a group of patients for four years who underwent coronary computed tomography angiography (CCTA) for major adverse cardiac events (MACE).We hypothesized that the results of this trial would reliably reflect the natural outcome of the coronary disease.Methods Consecutive patients who underwent CCTA from June 2008 to May 2009 were selected.Those who could not be reached by telephone,had significant angina,had CT images that were not interpretable,or poor kidney and left ventricular (LV) function were excluded.The patients were divided into five groups:group A normal CCTA without stenosis,group B mild stenosis (1％-49％),group C moderate stenosis (50％-74％),group D severe stenosis (≥75％) and they were treated with optimal medical therapy (OMT) or PCI.The group E had PCI before the CCTA examination.The patients were then followed for MACE after different treatments.MACE included acute myocardial infarction (MI),heart failure (HF) and death.Results The patient population consisted of 419 patients.The follow-up time was (51±5) months.The age was (60±31)years.Male made up 67.78％ of the population (n=284).A total of 51 cases of MACE occurred including 25 MI,eight HF and 18 all-cause deaths.There was no MACE in group A.Although MACE occurred in two patients in group B,they were not attributed to cardiac death.We further compared the MACE in groups C-E and no significant difference was found (P ＞0.05).However,a difference was detected among patients with unstable angina pectoris (UAP),stable angina pectoris (SAP),re-hospitalization,and cerebrovascular events from groups A-E (P ＜0.05).The plaque scores were used to predict MACE.The scores progressively increased significantly with lesion severity (P ＜0.05).Receiver operating curve (ROC) was performed to determine the sensitivity and specificity in predicting MACE.Our scores predicted MI with area of 0.76,predicted HF with area of 0.77,and predicted death with area of 0.70.Conclusions Normal and mild lesions had very few events.With increased stenosis the MACE rate increased progressively.PCI did not significantly reduce the MACE in comparison with OMT in asymptomatic patients.Furthermore,UAP,re-hospitalization,and re-PCI were significantly increased in patients who were treated with PCI.