Symptoms and diagnosis: The patient complains of a palpable throbbing mass in the abdomen, accompanied by vague abdominal pain. Examination: a throbbing mass can be touched in the midline of the abdomen, shuttle shape, unable to move, with deep pressure pain; blowing murmur can be heard on auscultation. If the abdominal pain is sudden or intensified, it often suggests that the tumor may rupture. If the rupture is small and in the posterior wall, retroperitoneal hematoma can be formed, and the bleeding can be stopped automatically after compression; if the rupture enters into the abdominal cavity, hemorrhagic shock can occur, and the patient can die if no timely operation is performed. If the tumor ruptures into the abdominal cavity, hemorrhagic shock may occur, and the patient may die if timely surgery is not performed. Sometimes, the tumor ruptures into the retroperitoneal space, resulting in swelling of the waist and hypochondrium and subcutaneous petechiae. Sometimes the tumor ruptures into the intestine, abdominal aortic-intestinal fistula can be formed, and gastrointestinal hemorrhage and shock can occur; individual tumor ruptures into the inferior vena cava, abdominal aortic-inferior vena cava fistula is formed, and the patient can have right heart hypertension, and the severe cases can be followed by right heart failure. According to the clinical manifestations of abdominal aortic aneurysm, combined with auxiliary examinations such as ultrasound, CT, MRI and abdominal aortography, the diagnosis can be clearly defined. Auxiliary examination can not only clarify whether the abdominal aortic aneurysm is suprarenal or infrarenal type, but also clarify the size and scope of the abdominal aortic aneurysm and whether it is accompanied by iliac artery lesions, which can provide a reliable basis for the choice of treatment. Abdominal aortic aneurysm is the most common type of aneurysm. Since the first description of abdominal aortic aneurysm in the 16th century, the incidence of abdominal aortic aneurysm has been increasing. This disease is very dangerous and can lead to death if not treated in time. Patients usually have no obvious clinical symptoms, and the disease is often detected during physical examination or abdominal surgery, especially ultrasound. Some emaciated patients can sometimes feel a pulsatile abdominal mass on their own. Individuals may sometimes have abdominal pain, mostly located around the umbilicus or in the mid-upper abdomen. The cause of the disease is not yet completely clear, but it is known to be related to atherosclerosis, more than 95% of developed countries in the West, and about 70% in China. It can also be caused by infection, melphalan, trauma, tuberculosis, leukoaraiosis or congenital dysplasia, etc. Marfan syndrome, polyarteritis and Ehlers-Danlos syndrome can also complicate this disease. Abdominal aortic aneurysms can have the following pathologic changes and consequences: ① Aneurysm rupture The wall of the aneurysm is often irregular, with varying thicknesses, and there is often calcification or atherosclerotic plaque, and the jet-like flow of blood becomes a vortex as it passes through the relatively narrow lumen of the vessel to the enlarged aneurysm. According to Laplace’s law, the more the artery expands, the greater the pressure on its wall. In this way, the aneurysm is progressively enlarged by long-term repeated action. In addition to aggravating pain and producing symptoms such as compression, due to the constant impact of blood flow, the aneurysm will eventually break through the weak point, causing serious bleeding. ②Aneurysm with wall thrombus formation There is often wall thrombus in the aneurysm cavity due to the rough wall and slow blood flow. The wall thrombus can sometimes be dislodged and produce arterial embolism distal to the aneurysm. Occasionally, a wall thrombus may completely block the aneurysmal lumen, usually only in the peripheral arteries. In the case of intimal atherosclerosis, dislodgement of atheromatous plaque and outflow of semi-liquid cholesterol-like material from the aneurysm lumen may also result in distal arterial embolization. ③Secondary infection Aneurysms can also be secondary to infection, which manifests as a sudden increase in symptoms and is characterized by inflammation. On the basis of infection and distal arterial embolism, aneurysms tend to rupture faster. The wall of the aneurysm, due to the effect of eddy current, withstands the impact of blood flow significantly increased, often causing the endothelium or the middle layer to rupture and separate to form an aneurysm-like hematoma of the lamina propria. At this time, the tumor body can rapidly increase in size, the symptoms worsened. General principle: when the tumor diameter is ≥5cm, due to the high chance of rupture, the tumor should be operated or intervened as early as possible; when the tumor diameter is <5cm, the tumor should be operated, intervened by endoluminal intervention, or followed by strict ultrasonography and outpatient visits. Once the tumor is found to increase rapidly or the patient has severe pain or the pain worsens suddenly, early surgery or endoluminal intervention should be performed. < font=""> Treatment: Suprarenal abdominal aortic aneurysm treatment: mainly open aneurysm resection and artificial vascular replacement, as well as related arteries such as renal artery, superior mesenteric artery, celiac artery, lumbar artery and other important arterial reconstruction. There are two types of treatment for infrarenal abdominal aortic aneurysms: First: open aneurysm resection and artificial vascular replacement. The second type: endoluminal abdominal aortic aneurysm repair.