Abdominal aortic aneurysm (AAA) is a common disease in vascular surgery, and surgical treatment of AAA has been a mature treatment method for more than 50 years. Open surgery is more traumatic, and patients are mostly of advanced age with relatively poor general condition, and there is a certain rate of complications during the perioperative period. A total of 329 cases of AAA open surgery were completed in the hospital from January 1991 to August 2009, and the complications are summarized as follows. Data and methods I. General data The 329 patients in this group were 254 (77.2%) males and 75 (22.8%) females, aged 14 to 84 years, with a median of 67 years. The combined diseases included hypertension in 134 cases (40.7), ischemic heart disease in 83 cases (25.2), diabetes mellitus in 32 cases (9.7), peripheral artery disease in 21 cases (6.4), cerebrovascular disease in 32 cases (9.7), and also combined iliac aneurysm in 37 cases (11.2). All cases were diagnosed by ultrasound and CTA, and the diameter of the aneurysm was 4.5-11.5 cm. 1. Surgical indications ① Symptomatic AAA. ② Asymptomatic but the diameter of the aneurysm was greater than 5.5 cm or the diameter of the aneurysm grew >0.5 cm/6 months. ③Diameter <5.5cm combined with the patient's wishes. ④The function of each important organ can be evaluated before surgery to tolerate open surgery. Most of the surgical procedures were performed under general anesthesia, but 12 patients used epidural anesthesia because they could not tolerate general anesthesia. A median abdominal incision was made from the subxiphoid process to 3-5 cm above the pubic symphysis, and the aneurysm neck and bilateral iliac (femoral) arteries were freed after opening the abdomen, and the standard method of vascular control was used to block the infrarenal abdominal aorta and bilateral iliac (femoral) arteries by administering heparin 0.5 mg/kg intravenously. -Bilateral iliac (femoral) artery bypass grafting with preservation of at least one internal iliac artery was performed. Results All 329 patients were successfully operated, with a 100% technical success rate. The open surgery included 5 cases of abdominal aortic replacement, 182 cases of abdominal main-double iliac artery graft, and 142 cases of abdominal main-double iliac femoral artery graft. The operative time ranged from 3 to 6 h, with a mean of (3.5±1.7) h. The ICU monitoring time ranged from 12 to 720 h, with a median of 19 h. Except for the early cases, a blood recovery device (Cell-saver) was routinely applied in the later patients. The average bleeding volume was (400±140) ml and the average blood transfusion volume was (360±140) ml. 3 patients died during the perioperative period, and the 30-d perioperative mortality rate was 0.91%. The incidence of major perioperative complications was 19.1% (63/329), including 21 cases of cardiac insufficiency or heart failure, 15 cases of respiratory insufficiency, 6 cases of heart infarction, 5 cases of renal failure, 6 cases of arrhythmia, 2 cases of cerebral infarction, 2 cases of lower limb arterial embolism, 2 cases of wound dehiscence, 1 case of abdominal wall incision hernia, 1 case of subcutaneous hematoma, and 2 cases of lower limb deep vein thrombosis. One patient with cardiac insufficiency or heart failure was treated with cardioplegia, diuresis, and fluid control, and the other four patients with respiratory insufficiency were treated with prolonged mechanical assisted ventilation, and one patient died of acute heart attack. One patient died of frequent ventricular premature and ventricular fibrillation 6 h after surgery, while the other 5 patients with arrhythmias improved after symptomatic treatment. 2 patients with postoperative cerebral infarction showed temporary hemiparesis and recovered after 4-6 h. 2 patients with lower limb artery embolism recovered after lower limb artery thrombectomy. All patients with wound dehiscence and abdominal wall incision hernia were reoperated and repaired. 2 patients with lower extremity deep vein thrombosis improved after anticoagulation therapy. Discussion AAA patients are mostly elderly patients, often combined with a variety of diseases, such as hypertension, coronary heart disease, chronic obstructive pulmonary disease, diabetes mellitus, etc. The chance of one or more organ insufficiency after surgery is greater, and if effective measures are not taken in time, it may lead to rapid deterioration of the condition and even endanger life. The highest rates of postoperative cardiac complications and respiratory insufficiency were observed in our patients, followed by renal insufficiency. Of the three patients who died in this group, one died of acute heart attack, one died of cardiac arrhythmia, and one died of renal failure. I. Cardiac complications The rate of combined coronary artery disease in AAA patients is high, second only to hypertension, accounting for about 20-30% [1], and therefore, the chance of perioperative cardiac accidents is also high, and perioperative myocardial injury is an important factor affecting the prognosis of AAA patients [2]. In our group, there were 21 cases of postoperative cardiac insufficiency, 6 cases of infarction, 6 cases of arrhythmia, and 2 of the 3 patients who died died from cardiac accidents, which should be of great importance to vascular surgeons. First, preoperative evaluation is crucial. Previous history of coronary artery disease, ECG with myocardial ischemic manifestations, and advanced age are high-risk factors. For the above patients, further cardiac examination is essential in addition to routine examination. In recent years, we routinely perform coronary CTA or myocardial nuclear examination in the above patients (advanced age is defined as age >70 years). If serious coronary artery lesions are found, interventional or surgical treatment of the coronary arteries is performed first if they are evaluated together with cardiologists and estimated to be at great risk for surgery. In addition, some studies have shown that the larger the diameter of the aneurysm, the greater the likelihood of postoperative cardiac accidents [3]. Second, it is important to pay attention to the monitoring and maintenance of intraoperative and postoperative cardiac function. Avoid large fluctuations in blood pressure intraoperatively, lower and raise blood pressure in advance when blocking the abdominal aorta and loosening the clamp, pay attention to the monitoring of central venous pressure, and precisely replenish blood volume to prevent heart failure. Some reports have shown that fluid load directly affects patient prognosis during the perioperative period [4]. Effective postoperative analgesia reduces stress response, decreases cardiac preload, controls blood pressure and heart rate, reduces oxygen consumption, and ensures blood oxygen partial pressure in favor of preventing myocardial infarction. Postoperative myocardial ischemia is easily induced in cardiac patients with a significantly lower than normal erythrocyte pressure product and must be corrected. II. Respiratory insufficiency Preoperative combined chronic obstructive pulmonary disease in about 30% of AAA patients has been shown to be an independent predictor of surgical death and prolonged hospital stay [5, 6]. The probability of respiratory failure is quite high due to postoperative restriction of abdominal breathing, poor sputum evacuation to respiratory tract obstruction and respiratory infection, and possible fibrin deposition in the lung capillaries of patients with massive blood transfusion, which hinders gas exchange. 15 cases of postoperative respiratory insufficiency were observed in this group of patients. In order to reduce the occurrence of postoperative respiratory insufficiency, we routinely performed pulmonary function tests and blood gas analysis before surgery, quit smoking for 2 weeks before surgery, helped patients to perform respiratory function exercises, and some patients had drug-assisted sputum excretion. Postoperative proper use of antibiotics and ventilator, assistance in sputum evacuation and effective pain relief are effective preventive measures. For those who had respiratory insufficiency, extended mechanical assisted ventilation was used, and positive pressure ventilation was used when necessary. 15 patients with respiratory insufficiency in this group were treated with extended mechanical assisted ventilation, and the longest duration of mechanical ventilation was 30 d. All of them improved and were discharged, and no patient died due to respiratory failure. Renal failure Renal failure is another serious complication of AAA open surgery. Intraoperative blockade of the aorta above the renal artery makes the kidney ischemic, and atherosclerotic plaque dislodged into the renal artery during the block are possible causes of damage to renal function. Patients with preoperative preexisting renal insufficiency are more likely to develop renal failure and are an important factor in the prognosis [7]. Glomerular filtration rate is a more accurate reflection of patient prognosis than blood creatinine [8]. Hemodialysis is an effective treatment for renal failure, but dialysis requires anticoagulation, which increases the risk of retroperitoneal and abdominal bleeding; therefore, the early postoperative appearance of renal failure often puts surgeons in a dilemma, but in patients with severe renal failure, there is no choice but to perform dialysis. Five patients in this group developed renal failure after surgery, one patient died after 20 d of ineffective dialysis, and the remaining four patients with renal failure improved after administration of diuretic therapy. Preoperative renal function was routinely evaluated, and if renal function was normal, there was no problem in tolerating 30 minutes of ischemia, and the tolerance time was shortened in those with impaired renal function. For AAA involving the renal artery and requiring suprarenal artery block, the tolerable renal ischemia time should be estimated according to the preoperative renal function, and for those estimated to be difficult to tolerate, the renal artery should be perfused with ice saline to protect the renal function. IV. Acute lower extremity ischemia Lower extremity ischemia is also a common complication after AAA open surgery. The main causes include atherosclerotic plaque detachment, floating endothelial sheets, technical causes including anastomotic stenosis and artificial vessel angulation and distortion. We routinely spray out some of the blood in the artificial vessel after revascularization, which can avoid the occurrence of arterial embolism. Angulation or twisting of the graft vessel is found and must be corrected and another vascular anastomosis is made if necessary. Poorly closed anastomoses should be resutured. Pre-existing atherosclerotic lesions and hypercoagulable state of the lower extremity and slow blood flow are also factors that cause postoperative arterial occlusion. When platelets adhere to the rough intima or the anastomosis of the grafted vessel, they tend to cause local aggregation of coagulation components, thus forming thrombus and blocking the lumen. Therefore, if the arterial block is prolonged, heparin should be supplemented to prevent secondary thrombosis. When arterial occlusion occurs after surgery, immediate surgical exploration should be performed, and appropriate treatment should be done according to the cause. In this group, two cases of acute lower limb ischemia occurred after surgery, and emergency surgical exploration was performed, both of which were arterial occlusions caused by dislodged atherosclerotic plaques, and the blood supply was restored to the affected limbs after embolization. V. Other complications AAA has some other complications, such as bleeding, sigmoid ischemia, anastomotic pseudoaneurysm, artificial vessel infection and rejection, etc. Most hospitals in AAA patients now use blood recovery devices, which can effectively reduce the amount of blood transfusion, but excessive heparinized red blood cell transfusion back can also cause disorders of coagulation mechanism, resulting in extensive blood leakage from the trauma and even postoperative formation of retroperitoneal hematoma. Attention should be paid to correct the disorder of coagulation mechanism, and timely replenishment of plasma and platelets as well as fibrinogen and other coagulation factors. No patients in this group were reoperated due to bleeding, and we routinely ligated the inferior mesenteric artery intraoperatively, and no patient developed significant colonic ischemia. No complications such as anastomotic pseudoaneurysm and artificial vessel infection occurred in all patients. AAA open surgery is more traumatic and has a greater impact on the cardiopulmonary function of elderly patients, and there is a certain incidence of complications in the perioperative period. Monitoring should be strengthened and lesions found should be treated in a timely manner to prevent the evolution of single-organ lesions into multi-organ failure and to reduce perioperative mortality and complication rates.