Coronary artery bypass grafting has been proven to be an important treatment to relieve angina symptoms and prolong the life span of patients with coronary artery disease, especially in patients with multiple lesions and diabetes. According to the statistics of Cosgrove et al, the rate of needing reoperation at 10 years is about 10%, and the number of patients needing reoperation at 20 years after surgery will increase significantly. The total number of patients undergoing secondary coronary artery bypass grafting in China is relatively small due to economic and cultural reasons, surgical techniques, and patients’ perception of fear of secondary surgery, and most of them have severe disease and serious adhesions, mostly diffuse lesions in three vessels. The time interval between the two procedures varies slightly, with an average time of about 8±5 years. Etiology of secondary coronary artery bypass grafting The reappearance of stenotic lesions in the coronary arteries after bypass grafting is divided into two time periods: early and late. The early stage refers to the period within 6 months after surgery, mainly due to technical problems in surgery, such as incomplete recanalization of the vessel that should have been bypassed, resulting in the reappearance of ischemic symptoms within a short period of time; acute and chronic thrombosis due to endothelial damage of the coronary artery or graft; improper selection of the target vessel, such as too small or The coronary artery itself is not severely stenosed resulting in significant postoperative competition for blood flow. Late stage means after 6 months, graft failure (venous intimal hyperplasia, fibrosis, atheromatous plaque formation) and progression of atherosclerosis are the primary causes. Surgical technical factors, antiplatelet therapy and neglect of secondary prevention are also important causes of reappearance of symptoms, and it is clinically found that reoccurrence of stenosis near the original anastomosis is very common in patients with secondary surgery. The literature reports that the 10-year patency rates of arterial and venous bridges are 85% and 61%, respectively, and the 10-year patency rate of internal mammary artery is up to 90%. It can be assumed that the chances of requiring secondary surgery after surgery are significantly higher in young patients who have not used arterial bridges and have not been completely recanalized. Indications for secondary coronary artery bypass grafting The 2010 European Heart Guidelines recommend secondary coronary artery bypass grafting for patients with multiple lesions, bridge occlusion, chronic occlusion of their own coronary arteries, and impaired cardiac function at Class IIa. The 2011 ACCF/AHA guidelines state that an anterior descending bridge diameter stenosis of ≥50% is indicative of re-bypass, and that if there is no ischemia in the anterior descending supply area, then the decision to perform a secondary bypass grafting procedure is a critical one. However, for patients with myocardial ischemia that cannot be controlled by drugs, multiple bridging vascular lesions, chronic occlusive lesions in coronary arteries, unsuitable for PCI, good distal target vessel conditions, and the possibility of applying internal mammary artery, surgical treatment is feasible. The guideline states that the treatment plan will be more reasonable when CABG patients are re-symptomatic after surgery, and the teamwork of medical-surgical and interventional surgeons. Surgical approach Most secondary coronary artery bypass grafting is performed using a median sternal incision, which has the advantages of good field exposure and ease of operation when dealing with emergent problems. For patients with single-branch lesions, small lower sternal incisions and thoracotomy approaches can be chosen depending on the location of the target vessel, graft material, and surgical procedure. A small low sternotomy can be performed for right gastroretinal artery-right crown anastomosis, and left anterior (external) and right anterior (external) thoracotomy can be used for bypass of the anterior descending branch and right crown, respectively. Patients undergoing secondary surgery have severe posterior sternal adhesions, which may damage the heart or existing vascular bridges during chest opening, and the application of electric knife may induce ventricular fibrillation, so extracorporeal defibrillation electrode plates are routinely applied, femoral arteries are prepared, and the routine extracorporeal circulation is loaded and pre-charged before surgery. In the first operation, because the pericardium is not sutured and/or the aortic root is not protected by the thymus gland, complications such as rupture of the heart, aorta and/or injury to the bridge vessels are very likely to occur during the opening of the chest, so CT examination of the aorta is routinely performed before surgery to observe whether there is a gap behind the sternum and to clarify the path, location and patency of the original bypass bridge. If necessary, femoral artery cannulation can be performed before opening the chest. Avoid damaging the bridge vessels, especially the internal mammary artery bridge, and avoid overstretching the venous bridge to prevent distal embolism caused by atheromatous plaque dislodgement. The bridge vessel material for secondary surgery can be chosen from internal mammary artery, radial artery, great saphenous vein, small saphenous vein, gastroretinal artery, and inferior abdominal wall artery. The choice of extracorporeal or non-extracorporeal subsurgical procedures depends mainly on the location of the coronary lesion, the severity of the disease, the skill and choice of the surgeon. He et al. concluded that prolonged extracorporeal time is a risk factor for increased mortality. Non-extracorporeal surgery is more advantageous for patients with severe aortic calcification and single-branch lesions in terms of reducing cerebral complications, but requires more technical surgical manipulation. More literature currently considers secondary coronary artery bypass grafting at room temperature to be safer, with statistically significant differences in operative mortality, transfusion volume, and length of hospital stay. For patients with severe aortic calcification and high risk of aortic coarctation and cerebral complications during upper blocking clamp or lateral wall clamp, technical methods such as using extracorporeal circulation under parallel surgery, Enclose proximal anastomosis device, making a Y- or T-shaped anastomosis proximally, or direct proximal anastomosis with the original bridge vessel can be chosen to reduce aortic manipulation during surgery, depending on the situation. The literature reports that surgical technique and prolonged extracorporeal circulation time are risk factors for mortality. For the original venous bridges, Mrshall et al. concluded that the usual bridges less than 5 years old should be retained and all venous bridges older than 5 years should be removed and re-bypassed. However, Turner et al. concluded that manipulation of venous bridges should be minimized to prevent distal embolism caused by dislodged emboli. Risk factors associated with death include low EF, advanced age, female gender, history of arrhythmia, unstable angina, renal insufficiency, emergency surgery, and prolonged extracorporeal circulation. The risk of death in secondary surgery is significantly higher than that in primary surgery, with mortality rates reported abroad ranging from 4.8 to 16%, and 7% in Fu Wai Hospital. The survival rates at 1, 3, 5 and 6 years for secondary coronary artery bypass grafting were 93.1%, 90.5%, 85.9%, and 80.5%, respectively, which were significantly lower than those for the first operation and less significant than those for the first operation in relieving angina symptoms. This is both an opportunity and a challenge for cardiac surgeons. Along with the improvement of medical technology in cardiac surgery, anesthesia and monitoring rooms, the safety and long-term survival rate of secondary surgery will be significantly improved.