Abstract: AIM:To investigate the effect of percutaneous coronary intervention (PCI) on clinical symptoms, left ventricular function, survival rate and quality of life in patients with at least one chronic total occlusion (CTO). METHODS: Patients admitted to the hospital from July 2007 to December 2008 and treated with PCI were included in the study when coronary angiography showed at least one main coronary artery occlusion. Patients were divided into PCI-success group or PCI-failure group according to the PCI results of occluded vessels. Anterograde approach and dedicated coronary wires were applied in the intervention operation. Patients were followed up at 1 year after PCI. Statistical differences of death, myocardial infarction, stroke, re-PCI and CABG between groups were evaluated. RESULTS: From July 2007 to December 2008, among the 1490 patients with abnormal coronary angiography results, 434 patients underwent PCI for at least one CTO. Of the 434 cases, the occluded vessels were treated successfully in 316 patients (72.8%). In the PCI-failure group, the average age was higher and more patients had a smoking history. Ratios of prior revascularization or coronary artery bypass graft (CABG) history in PCI-failure group were significantly higher than in PCI-success group. No obvious differences were observed in hypertension, hyperlipidemia, previous myocardial infarction, diabetes mellitus and cardiac function between groups. More patients in PCI-failure group had two CTOs and multivessel lesions (P<0.01 & P<0.01, respectively). Angina pectoris and selective CABG operation were significantly higher in PCI-failure group than those in PCI-success group (P<0.01 & P<0.01, respectively). No obvious differences between groups were seen in the death rate, myocardial infarction, stroke and re-PCI. CONCLUSION: Successful PCI therapy of CTO reduces rates of recurrence of angina pectoris and CABG operation, but no significant differences were found in the rates of death, myocardial infarction, stroke and re-PCI.