Indications for CABG (coronary artery bypass grafting) 1. asymptomatic or mildly symptomatic AP The aim of CABG in such patients is not to eliminate symptoms, but rather to improve life expectancy and survival compared with non-surgical treatments (drugs and interventions). LM and LM-like lesions, and three-branch lesions are clear indications for surgery for CABG. In contrast, surgery is preferred for single or double-branch lesions that include proximal stenosis of the LAD. The PTCA technique is gradually entering the field of treatment of LM stenotic lesions. For normal LV function, especially in combination with surgical contraindications (such as renal insufficiency or severe pulmonary dysfunction), PTCA can be considered as an alternative treatment to CABG, but requires very high interventional skills. If the LV function is low, the risk of CABG treatment is not high, and the patient is not skilled in the interventional technique, CABG should be performed early and relatively safer. 2. Stable AP The purpose of CABG in these patients is to prolong life and relieve symptoms. The indications for CABG in these patients are the same as above. CABG is also strongly recommended for bifurcation lesions with significant proximal LAD stenosis including EF <50% or non-invasive tests suggesting the presence of myocardial ischemia, due to the worsening of symptoms compared to the former, whereas for single or bifurcation lesions not involving the proximal LAD, critical coronary stenosis (50-60% lumen reduction except LM) without evidence of myocardial ischemia, insignificant coronary stenosis ( PTCA has been widely used for CAD treatment of three or even multiple lesions. The rate of recanalization required after PTCA is higher than that of CABG. 5-year survival rate is higher in DM patients with CABG than in PTCA group. CABG has a higher initial surgical mortality rate than PTCA group. Therefore, it is important to communicate well with these patients to keep them informed and decide together the best treatment plan for them. The indication of CABG for unstable AP/non-Q-wave MI in these patients is related to both life extension and symptom relief. Therefore the first two indications for CABG are both applicable to such patients. The timing of surgery is the key issue. The degree of patient stability is an independent risk factor for postoperative mortality. Therefore, clinical emphasis is strongly placed on treating such patients with the maximum dose of medication they can tolerate and waiting for their condition to stabilize and progressive ischemia to resolve before performing CABG. 4. MI with ST-segment elevation (with Q waves) The final infarct size and risk of death are closely related to the time from symptom onset to coronary reperfusion, and CABG requires longer time to reestablish coronary circulation than thrombolysis and PTCA treatment However, with a higher degree of reperfusion after surgical treatment, patients may have a smaller final infarct size than with thrombolysis or PTCA. Nevertheless, CABG should only be considered in these patients in exceptional circumstances. Early CABG should be considered in AMI with residual progressive ischemia despite nonsurgical treatment and when imaging shows suitable target vessels in both the infarcted and noninfarcted areas. CABG may be considered in AMI with LM stenosis, severe triple-branch disease, associated valvular disease (whether secondary to AMI or not), and complex anatomic conditions. (whether secondary to AMI or not), and complex anatomic conditions that are not amenable to other treatments. Summary of indications for CABG: Emergency CABG is generally not indicated in these patients, but may be attempted in cases of progressive myocardial ischemia/infarction where intensive nonoperative therapy has failed, if there is surviving myocardium and a suitable target vessel for bypass. 5. LM insufficiency Inadequate Patients undergoing CABG with LM insufficiency have higher perioperative and long-term mortality than those with normal LM function. The effect of surgery depends on the amount of surviving myocardium of the patient, if more, CABG can stabilize and improve LM function in these patients, especially LM insufficiency patients with intermittent ischemia and no or only very mild manifestation of congestive heart failure are particularly suitable for surgical treatment; on the other hand, if the patient has prominent manifestation of chronic heart failure without obvious AP, surgical decision should be considered with or without hibernating myocardium objective basis. Randomized trials have shown that survival after CABG is higher in patients with LM lesions, three or two branches including LAD, combined with LV insufficiency than in patients treated with drugs. CABG in patients with severely hypofunctional LM can have a good surgical outcome if (1) there are preoperative symptoms of AP, (2) the preoperative examination of hibernating or surviving myocardium is high, and (3) the angiography suggests at least two or more vessels that can be bypassed with distal patency. CABG is not appropriate in patients with LM insufficiency, no evidence of intermittent ischemia, and no significant evidence of resuscitable surviving myocardium. The possibility of a left ventricular assist device or heart transplantation should be considered at this time. 6. Fatal ventricular arrhythmias CABG has a higher survival rate and a lower probability of secondary fatal rhythm than drug therapy alone. CABG is more effective for ventricular fibrillation than ventricular tachycardia. CABG is not advocated for ventricular tachycardia with myocardial scarring and no evidence of ischemia. 7. CABG after failed PTCA Making an emergency CABG decision after a failed PTCA procedure is more complex. Key considerations include the cause of PTCA failure, the likelihood of surgical success, the degree of myocardial damage, and the general condition of the patient. Factors affecting the outcome of the procedure include the patient's own condition (e.g., left heart insufficiency, advanced age, extent of multiple lesions, and degree of collateral circulation formation) and also depend on the total ischemic time, which includes the delay in transport to the operating room, when there are dangerous hemodynamic changes, the patient is at significant risk of myocardial infarction or the guidewire or stent is misplaced at a critical site, and the choice of CABG is very clear. Emergency CABG after failed PTCA has a higher mortality and infarction rate compared to elective CABG. Therefore, emergency CABG is not recommended if PTCA fails without a basis for myocardial ischemia, or if the target vessel is poorly patented distally. For patients with coronary artery disease, CABG is only a palliative procedure and does not prevent the progression of vascular disease or cure the disease. There may be a 5% or higher annual recurrence rate of AP 1 year after surgery. This is almost always associated with bridge vessel occlusion, progression of atherosclerosis in unbridged coronary arteries, and, less commonly, lesions in vessels distal to the bridge. 5-7 years of atherosclerosis in venous bridges resulting in bridge vessel occlusion becomes the main reason for surgery. The indications for reoperation are the same as the initial indications, with the difference being the higher surgical risk, with an approximately 3-fold higher risk of in-hospital mortality compared to the initial procedure. Moreover, reoperation is not as effective as the first surgery in relieving symptoms and prolonging life. Therefore, reoperation is generally considered only to relieve severe symptoms or when a non-invasive examination reveals a large area of myocardium on the verge of infarction. In such patients, PTCA has a relatively high value, especially when applied to the vessel with the original lesion. PTCA applied to graft stenosis is significantly less effective than the original lesion.