Cardiac bypass, or coronary artery bypass grafting, is a surgical procedure to reconstruct the blood channels of the ischemic myocardium and to improve the blood supply to the myocardium and the lack of oxygen. Coronary artery bypass grafting is mainly performed by end-to-end anastomosis between the internal thoracic artery and a branch of the stenotic artery; or by taking a section of the autologous saphenous vein and performing end-to-end anastomosis between its distal and proximal ends with the ascending aorta and a branch of the stenotic coronary artery, respectively. The indications are patients who cannot be relieved by medication or who have frequent angina pectoris; patients with coronary angiography-confirmed left main stem lesions or severe three-branch lesions. Significant cardiac enlargement, severe pulmonary hypertension, right heart failure, or severe hepatic or renal insufficiency are considered contraindications to the procedure. If there is any discomfort, it is recommended to seek prompt medical attention and treatment.