An abdominal aortic aneurysm is a dilated bulge in the wall of the abdominal aorta. The aneurysm can grow in size and eventually rupture and bleed, leading to the patient’s death. Abdominal aortic aneurysms occur mainly in older people over 60 years of age, with a male to female ratio of 10:3. They are often associated with hypertensive disease and heart disease, but are occasionally seen in younger people as well. They are more common in men than in women. Other rare causes are congenital dysplasia of the aorta, syphilis, trauma, infection, aortitis, and Marfan syndrome. Most abdominal aortic aneurysms are caused by atherosclerosis and are usually located distal to the renal artery, extending to the bifurcation of the abdominal aorta, often involving the iliac artery, and occasionally above the renal artery. Some patients may be asymptomatic before rupture or near rupture. The common causes include atherosclerosis, cystic degeneration of the middle layer of the artery, syphilis, congenital, traumatic, and infectious. Among them, atherosclerosis is the most common cause. When atherosclerosis occurs in the artery, the middle elastic fibers break down and the wall becomes weak, so it cannot withstand the pressure of blood flow in the aorta and becomes locally enlarged, forming an aortic aneurysm. Due to the high pressure of blood flow in the aneurysm, the aneurysm gradually expands and can compress the adjacent organs, even erode the sternum and ribs or bulge out to the body surface, becoming a pulsating mass. In the enlarged aneurysm, blood flow is slowed down and vortexes are formed, which can produce attached wall thrombus. Patients can die due to severe compression of vital organs or self-rupture of the aneurysm. Cystic aneurysms are more likely to rupture than pyknotic ones. Symptoms: Rare before the age of 50, most commonly seen in men between the ages of 60-80. 1. Most patients are asymptomatic and are often found incidentally for other reasons on physical examination. The typical abdominal aortic aneurysm is a swollen mass pulsating laterally and anteriorly and anteriorly, and is accompanied by a vascular murmur in about 50% of patients. 2. Pain: It is a common symptom before rupture and is mostly located around the umbilicus and in the middle and upper abdomen. If the aneurysm invades the lumbar spine, there may be lumbosacral pain. If there is severe pain in the abdomen or lumbar area recently, it often indicates that the aneurysm is on the verge of rupture. Abdominal mass: The most important sign is a distending, pulsating mass around the umbilicus or in the upper and middle abdomen, which is usually palpable unless the patient is obese. The femoral artery or dorsalis pedis artery pulsation is weakened or absent. Rupture: It can be the first symptom of fatal complications, most commonly rupture of the tumor, blood from the tumor into the peritoneal cavity, fortunately more commonly into the retroperitoneal cavity, the bleeding from this part is slow. Abdominal pain and shock from blood loss can last for hours or days, and the patient may seek medical attention. Occasionally, the bleeding is limited, and the patient may have abdominal pain, fever, mild to moderate blood loss, and often rupture again. It may also rupture into the inferior vena cava, producing an aorto-venous fistula with a continuous murmur, high cardiac output, and heart failure. Occasionally, it may enter the duodenum and cause gastrointestinal bleeding. 4.Other serious complications: Acute thrombosis may occasionally be formed in the aneurysm. Abdominal aortic aneurysm thrombosis or atherosclerotic debris can cause lower limb embolism. Intestinal obstruction may occur due to duodenal compression, and peripheral edema may be caused by inferior vena cava obstruction. Secondary bacterial infections are rare. There are currently seven methods for exploring abdominal aortic aneurysms and estimating their size and extent: 1. abdominal palpation, which is the least accurate. 2, abdominal radiograph: if there is a typical oval shell-shaped calcification shadow, the diagnosis can be established, but at least 1/4 of the patients do not have this sign. 3.Two-dimensional ultrasonography: It is valuable for the diagnosis of abdominal aortic aneurysm, easy to operate, with high accuracy in detecting aneurysm, and can clearly show its shape and attached thrombus, which is the preferred diagnostic method at present. 4, abdominal aortography: accuracy is not high, because the width of the aneurysm can be masked by translucent wall thrombus. However, the imaging results often provide valuable information, so it is still a necessary preoperative test. 5.DSA: The results are similar to those of abdominal aortography without the need for intra-arterial injection of contrast agent. 6.CT: Compared with two-dimensional ultrasonography, it can show abdominal aortic aneurysm and its relationship with surrounding tissue structures such as renal artery, retroperitoneum and spine, as well as retroperitoneal hematoma more clearly. However, the cost is higher and the operation time is longer. 7.MRI: Its diagnostic value is similar to ultrasound and CT, but the disadvantage is that it is expensive and time-consuming to operate, but the imaging time will be greatly shortened by the new generation products. Abdominal aortic aneurysm may heal by itself without medical treatment, but the most serious local consequence is death by rupture and bleeding, and the main treatment is surgery. Disease prevention: First of all, we should actively prevent the occurrence of atherosclerosis (primary prevention), if it has already occurred, we should actively treat it to prevent the development of the lesion and strive for its reversal (secondary prevention). If complications have already occurred, timely treatment should be given to prevent its deterioration and prolong the patient’s life (tertiary prevention). Abdominal aortic aneurysms occur mainly in the elderly population over 60 years of age and are often associated with hypertensive disease and heart disease, but they are also occasionally seen in younger people. It is more common in men than in women. The disease is like a time bomb in the body, with a mortality rate of 50%-80% if it ruptures. Most patients are found on physical examination with a pulsating mass in the abdomen. The 5-year survival rate of surgically treated abdominal aortic aneurysms can be more than 60. The main causes of death are heart disease, malignant tumors, and cerebrovascular accidents, and are not related to surgery of the abdominal aorta. In recent years, due to the continuous improvement of medical technology, the mortality rate of surgery has been greatly reduced, postoperative complications have been greatly reduced, and elective resection of abdominal aortic aneurysm has become a safer surgery.