Inclusion Criteria:(A patient will be included in the study when the following criteria and requirements are met)  ① Patient age of ≥25 years but ≤85 years, and patients with CAD who require multivessel coronary bypass surgery. ② Angina that affects daily life and work and is uncontrollable with conservative treatment. ③ Significant stenosis in the left main (LM) coronary artery, left anterior descending (LAD) branch or left circumflex (LCX) branch >70%. ④ Severe stenosis (stenosis degree >75%) of three main branches of the coronary artery (anterior descending branch, circumflex branch, right coronary artery) with the need to undergo off-pump coronary artery bypass surgery.  Exclusion Criteria:(A patient will be excluded from the study if they meet any of the following criteria)  ① Unstable preoperative hemodynamic status (vasoactive drugs such as dopamine, epinephrine or norepinephrine to maintain blood pressure, or an intra-aortic balloon pump [IABP] is implanted preoperatively) or requiring emergency surgery. ② Severe emphysema, hypoxemia [postbronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<70% and FEV1% predicted<50% or partial pressure of oxygen (pO2)<60 mmHg or partial pressure of carbon dioxide (pCO2)>40 mmHg without oxygen therapy. ③ Old extensive myocardial infarction without a viable myocardium based on isotope and echocardiography examination, significant cardiac enlargement (cardiothoracic ratio>0.75, EF<30%, left ventricular diastolic diameter (LVDd)>60 mm, left ventricular aneurysm or severe arrhythmia). ④ Severe pleural adhesion, chest deformity, or previous thoracic radiotherapy. ⑤Previous thoracotomy surgery. ⑥ Simultaneous valve or other cardiac surgery. ⑦Planned cardiopulmonary bypass surgery. ⑧Poor condition of the distal coronary artery (diffuse stenosis, chronic total obstructive lesion with severe calcification or inability to match the graft due to a small diameter (<1.0 mm). ⑨Intolerance to surgery in combination with the following complications: Terminal cancer, uncontrolled infection, bleeding, severe brain injury, infarction or bleeding, multiple organ failure and other major organ dysfunction such as severe liver dysfunction or severe congestive heart failure.