Patients with coronary artery disease are often combined with multi-organ and systemic diseases, such as hypertension, diabetes, abnormal lipid metabolism, cerebrovascular disease, lung, kidney and other organ function decline, thus, determining the special nature of perioperative management in coronary surgery. Reasonable mastering of surgical indications and proper perioperative management are important to reduce the occurrence of postoperative complications, shorten hospitalization time and reduce medical costs. 1, the selection of surgical indications Currently, it is recognized that patients with severe coronary artery disease should be actively treated with surgical procedures. These include severe lesions of the left main stem of the coronary artery, lesions of three vessels, lesions of two branches involving the proximal segment of the anterior descending branch or with significant impairment of left ventricular function, and giant ventricular wall tumors. Patients with unstable angina, such as unsuccessful drug treatment, severe ischemia on ECG during pain attack, impaired left heart function and angina attack after myocardial infarction, should also actively consider coronary artery bypass graft surgery when combined with coronary angiography analysis. (1) Preoperative application of β-blockers, nitrates, calcium antagonists, angiotensin-converting enzyme inhibitors and other drugs according to the condition to adjust heart rate, blood pressure, reduce myocardial oxygen consumption and control angina attacks. Regulation of blood glucose and blood lipids, and improvement of general condition. Clarify the functional status of lung, brain, liver, kidney, digestive system and other organs and systems, and carefully evaluate high-risk factors to guide intraoperative and postoperative management. (2) Ensuring intraoperative perfusion of all organs and tissues is a core aspect. The autoregulation of blood flow in the brain, kidneys and other organs is diminished, and if insufficient perfusion occurs, it is easy to cause postoperative organ functional impairment. Therefore, during surgery, the extracorporeal circulation should ensure sufficient perfusion pressure, and a mean arterial pressure of 60-80 mm Hg (1 mm Hg = 01133 kPa) is appropriate. To reduce the systemic inflammatory response, bleeding tendency, and pulmonary dysfunction caused by extracorporeal circulation, glucocorticoids and high-dose peptidase can be applied intraoperatively. Sudden onset of severe hypotension in the late surgical period should be treated urgently by identifying the cause. Common causes include acute thrombosis of the graft vessel, twisting and folding, bleeding from ligated branches, anastomotic bleeding pericardial tamponade, anaphylactic shock with fisetin, acute myocardial infarction, etc. There have been cases of acute thrombosis of saphenous vein graft vessels, some of which caused hypotension and even death from postoperative myocardial infarction complicated by multiorgan failure. After we found the above, we immediately re-bypassed the graft under extracorporeal circulation, removed the intracoronary thrombus and flushed the coronary artery with urokinase. It has been reported abroad that severe allergy to fisetin can lead to a sudden drop in blood pressure and cardiac arrest, and if treatment with glucocorticoids and epinephrine is not effective, extracorporeal circulation should be performed immediately to assist. (3) Postoperative patients often suffer from hypothermia, surgical stress, hypovolemia, increased peripheral resistance resulting in hypertension, tachycardia, and increased myocardial oxygen consumption. Metabolic acidosis further hinders tissue oxygenation and should be corrected promptly. Treatment includes application of vasodilators to improve peripheral circulation, use of beta-blockers or calcium channel blockers to slow the heart rate, supplementation of colloids, volume replacement, promotion of diuresis, reduction of edema, and intravenous infusion of sodium bicarbonate to regulate the acid-base level. Maintenance of respiratory function is another key to postoperative management. A variety of causes can lead to respiratory insufficiency and hypoxemia in patients. The formation of pleural effusion is associated with the opening of the pleural cavity when the internal mammary artery is taken. In patients with preoperative chronic obstructive pulmonary disease, inflammation should be controlled and respiratory function exercises should be performed; intraoperative attention should be paid to protecting the phrenic nerve, avoiding excessive blood transfusion, applying antispasmodic and wheezing drugs to control asthma; β-blockers should be used cautiously. In patients with cardiogenic asthma, attention should be paid to the presence of perioperative myocardial infarction. Once the standard lead ECG indicates obvious myocardial ischemia, occlusion of the graft vessel should be highly suspected, and the graft should be opened and explored as soon as possible, and the graft should be re-bypassed as soon as it is confirmed. Sudden wheezing of unknown origin, some of which can be rapidly relieved by dexamethasone and aminophylline drip, may be related to increased postoperative airway stress and rapid-onset allergic reactions. Severe respiratory insufficiency should be treated with mechanical ventilation to correct hypoxemia as soon as possible. Preoperative respiratory function and arterial blood gas measurement can help guide postoperative respiratory therapy. (4) Perioperative myocardial infarction is a serious complication of coronary artery bypass graft surgery. Elevated serum phosphocreatine isoenzyme, acute myocardial infarction manifestations on ECG, and hemodynamic deterioration may suggest the diagnosis. The cause may be related to poor myocardial protection, prolonged blockade, vasospasm, coronary embolism, graft vessel or coronary thrombosis. Postoperative monitoring of standard lead ECG and dynamic observation of myocardial enzyme changes should be established as routine. Prevention should focus on shortening the operation time, completely reconstructing myocardial blood flow, choosing reliable coronary artery site anastomosis, carefully venting the graft vessel, rational operation to reduce embolism, and applying calcium channel antagonists to prevent and relieve vasospasm. The prognosis of perioperative anterior wall myocardial infarction is mostly poor, while limited myocardial infarction at other sites can generally be stabilized by conservative treatment. Therefore, if abnormal ST-segment elevation cannot be controlled by drugs in postoperative anterior chest leads, we advocate active open-chest investigation to clarify the diagnosis as early as possible; if we wait for the occurrence of severe myocardial infarction before treatment, it will delay the timing of treatment. In one patient, dyspnea, cold extremities, arterial partial pressure of oxygen 50 mm Hg, hypotension, elevated myocardial enzymes, and acute myocardial infarction on electrocardiogram occurred in the 3rd postoperative day, so emergency tracheal intubation, positive inotropic drugs and IABP assistance were performed. Atrial fibrillation and supraventricular tachycardia (supraventricular tachycardia) are the most common postoperative arrhythmias. Recurrent or prolonged episodes can severely disrupt hemodynamics and delay recovery. Risk factors for atrial fibrillation include right coronary artery stenosis, advanced age, male gender, history of atrial fibrillation, history of congestive heart failure, decompression via the right superior pulmonary vein during surgery, and prolonged myocardial block. Atrial fibrillation causes anxiety, discomfort, decreased cardiac output, and increased myocardial oxygen consumption in patients. The treatment principle is to correct acid-base electrolyte balance, improve hypoxia and balance the volume, and slow down the ventricular rate with intravenous cidilan, acetaminophen has the effect of converting the rhythm and dilating the coronary arteries, and β-blockers such as esmolol also have better effect. Some patients developed postoperative cerebral complications in those with significant atherosclerosis of the ascending aorta or carotid arteries. The emboli may originate from atherosclerotic plaques detached from the ascending aorta and carotid arteries. Those with severe carotid artery stenosis are prone to intraoperative cerebral hypoperfusion resulting in cerebral ischemia. Preoperative carotid endarterectomy may reduce the incidence of cerebral complications in this group of patients. In case of cerebral impairment, comprehensive measures such as dehydration, hypothermia, sedation, application of hormones and cerebral protective drugs, ensuring oxygen supply and nutritional support should be implemented in a timely manner. In some patients with upper gastrointestinal bleeding, H2 receptor antagonists can be routinely applied postoperatively, and irritating oral drugs should be avoided in the early stage. Early postoperative anticoagulation with low-molecular heparin or warfarin is used, and aspirin is changed to aspirin after normal feeding. There were deaths due to multiple organ failure complicated by recurrent upper gastrointestinal bleeding. Treatment of severe infection of the incision and sternum is time-consuming, laborious, and expensive and should be avoided at all costs. Risk factors include uncontrolled diabetes mellitus, prolonged exposure of the incision, too deep and excessive free tissue when taking the internal mammary artery; osteoporosis, splitting of the sternum, poor wire fixation, and postoperative violent coughing that can easily cause sternal doffing can also lead to infection. Severe infections cannot be treated by antibiotics and must be surgically cleared. Through reasonable and strict perioperative management, good results can be achieved in the surgical treatment of severe coronary artery disease. Reasonable selection of surgical indications, adequate estimation of high-risk factors and purposeful perioperative management are the keys to successful treatment.