According to the CREATE (Multi - Center Registry of Excel Biodegradable Polymer Drug Eluting Stent) registration results show that ExcelTM drug-eluting stents implanted an average of 12 months, target lesion (TLF) the failure rate of 6.7%.Will this study expected target lesion group stent failure rate estimate of 6.7%, the target is 9.5%;Test hypothesis: bilateral 0.05% 0.05%, master degree, clinical follow-up requirements is more than 95%, this research need at least 829 patients, remove the CREDIT II randomized controlled study can provide the number of cases of test group 208 examples, this study still need to be included in the 621 patients.