A Single-center, Prospective,Randomized Study of Antiplatelet Effects of Ticagrelor Versus Clopidogrel in Patients With Dual Anti-platelet Therapy After Coronary Artery Bypass Grafting

Inclusion Criteria: * Female and/or male and ≥ 18 and \<80 years of age * Isolated CABG for the first time * either on- or off- pump Exclusion Criteria: * Combined valvular surgery. * A second surgery. * Emergency surgery (a selective operation which change to emergency surgery in some special medical condition). * Serum creatinine\>130μmol/L. * Oral clopidogrel therapy stops less than 5 days before the surgery. * Oral anti-coagulation therapy (warfarin) that cannot be withheld. * History of gastrointestinal or vaginal bleeding, Active pathological bleeding (e.g. active gastroduodenal ulcer or cerebral haemorrhage), history of postoperative gastrointestinal bleeding. * Uric acid nephropathy, history of postoperative gastrointestinal bleeding. * History of cerebral haemorrhage. * Any other condition that may influence platelet count and function. * Postoperative chest drainage \> 200 ml/hr for two hours and more, re-operation for bleeding with persistent cardiac tamponade. * Treated with IABP or ECMO after operation. * Any other condition that may put the patient at risk (e.g., recurrent ventricular arrhythmias, peri-operative myocardial infarction, cancer). * Contraindication to aspirin, clopidogrel and ticagrelor or other reason that study drug should not be administered (e.g., hypersensitivity, moderate or severe liver disease). * Previous enrollment in other investigational drug or device study within 30 days. Being or planning to pregnant.