It is not a benign or malignant tumor as it is often called, but an aneurysm formed when the wall of the abdominal aorta loses its normal structure and the blood flow increases the impact pressure on the vessel wall, causing the abdominal aorta to dilate. Abdominal aortic aneurysm is like a bomb in the stomach, which is at risk of rupture at any time when there are irritating factors, such as elevated blood pressure, cough, emotional excitement, trauma, etc. Once an abdominal aortic aneurysm ruptures, arterial blood with high pressure will flow from the rupture of the abdominal aorta into the retroperitoneum or abdominal cavity, and the patient will soon be in a state of shock, with blurred consciousness or even coma, reduced blood pressure, and life at risk. In the past 30 years, with the continuous development of vascular surgery technology in hospitals, adequate preparation before surgery, proper treatment after surgery, and continuous improvement of surgical methods, the mortality rate of patients with abdominal aortic aneurysm has been greatly reduced, so that they can be timely and accurately diagnosed and treated, and the complications can be effectively reduced, so that many patients with abdominal aortic aneurysm can be cured and their lives can be prolonged. I. Pathogenesis and causes The main cause of abdominal aortic aneurysm is abdominal aortic atherosclerosis, which accounts for about 95%, while others are traumatic, infectious, degenerative changes in the middle layer of the arterial wall, congenital, non-infectious aortitis and syphilis. II. Patients with abdominal aortic aneurysm are mostly elderly men, often above 60 years of age. Most of them have hypertension, hyperlipidemia, constipation or chronic cough, or have atherosclerosis in other parts of the body. III. Clinical manifestations Most patients have a pulsating mass in the abdomen around the belly button during physical examination or unintentionally, without other symptoms. If the aneurysm enlarges to a certain extent, it will produce compression symptoms on the surrounding tissues and organs, for example: compression of the sigmoid colon or rectum will cause constipation; compression of the duodenum will cause intestinal obstruction, manifesting as abdominal pain, vomiting and abdominal distension; if the aneurysm enlarges and penetrates into the duodenum or jejunum, upper gastrointestinal bleeding will occur, manifesting as vomiting coffee-like substances; compression of the common bile duct will result in yellowing of the skin and sclera and a significant increase in body temperature; compression of the inflowing duct will result in a significant increase in body temperature; compression of the inflowing duct will result in a significant increase in body temperature. Compression of the ureter may cause hydronephrosis, renal colic or hematuria; compression of the bladder may result in frequent urination and fluctuating urine flow. When the aneurysm invades the lumbar spine, there may be lumbosacral pain. If the thrombus is dislodged in the branch arteries of the abdominal aorta, acute ischemic symptoms of the branch arteries may occur, for example, if the blockage is in the celiac artery or superior mesenteric artery, it may cause postprandial abdominal pain; if the blockage is in the arteries of both lower limbs, it may cause sudden coldness, numbness and pain in both lower limbs; if the blockage is in the renal artery, acute renal insufficiency may occur. If the renal artery is blocked, acute renal insufficiency will occur, manifested as sudden increase in blood pressure, urea nitrogen and creatinine. There is another type of sudden pain in the lower back or abdomen that should be alerted to the possibility of a coarctation aneurysm formation. The most dangerous thing is that the wall of the aneurysm becomes thinner and thinner, and when stimulated by increased blood pressure, the tension on the vessel wall increases significantly, thus causing the weak part of the arterial wall to expand more and more, which eventually leads to the rupture of the arterial wall, resulting in hemorrhagic shock and even threatening life. The most important sign of abdominal aortic aneurysm is a swollen, pulsating mass around the umbilicus or in the middle and upper abdomen, ranging from 4 to 20 cm in diameter. In the early stage of the disease, there is no pressure pain on the aneurysm, but when it increases to a certain level, there may be varying degrees of pressure pain, and systolic murmurs and tremors may be heard to the touch. When the tumor enlarges to a certain degree, it may cause ischemic symptoms in the lower limbs, and the pulsation of the posterior tibial artery and dorsalis pedis artery may be weakened or disappear. The symptoms of acute lower limb ischemia may include cold skin temperature, pale skin color and nail bed, and even inability to move the lower limbs and foot drop. The tumor compresses the iliac vein and causes swelling of the lower limbs. Compression of the spermatic veins may cause varicose veins. Patients with abdominal aortic aneurysm are often accompanied by hypertension (60%). It is important to pay attention to the systemic conditions of heart, brain and kidney, and check whether there are manifestations of coronary heart disease, cerebral thrombosis or sequelae of cerebral hemorrhage, renal insufficiency, etc. IV. Examination methods 1. abdominal plain film: calcified curved shadows, resembling eggshells, can be seen on one or both sides of the lumbar spine. The soft tissue shadow of the tumor, the shadow of lumbar muscle disappears or the vertebral body is destroyed. However, in the early stage when the mass is small, the patient is young or the tumor wall is not calcified, the shadow of calcification is not easily seen. 2.Ultrasonic examination: B-type ultrasound and color Doppler ultrasound examination can help to diagnose abdominal aortic aneurysm. According to the scanned images, the following issues can be understood: ① the presence or absence of abdominal aortic aneurysm; ② the diameter and size of abdominal aortic aneurysm, the accuracy of which can reach ±3mm; ③ the presence or absence of thrombus formation in the aneurysm cavity, the site, size and scope of thrombus and the caliber and size of the channel in the aneurysm cavity; ④ the pulsation of the aneurysm wall (4) the amplitude of the pulsation of the aneurysm wall; (5) further understanding of the size, rule and degree of calcification of the lumen diameter of the upper and lower abdominal aorta of the abdominal aortic aneurysm; (6) understanding the relationship between the upper abdominal aorta on the renal artery and the diaphragm; (7) because ultrasonography is a non-invasive examination, it can be used to follow up surgical or non-surgical patients to understand the effect of surgery or the degree of growth of the aneurysm; it can also understand the leakage between the abdominal aorta and the arterial wall sandwich. 3.Doppler non-invasive vascular examination: it can clarify the blood supply of both lower limbs, and understand whether there is stenosis and obstruction in the iliac artery and both lower limbs arteries. 4.Electron computed tomography (CTA): It has obvious superiority in diagnosis and measurement of suprarenal abdominal aortic aneurysm, thoracoabdominal aortic aneurysm and abdominal aortic aneurysm involving common iliac artery. From imaging it can obtain images of various cross-sections of the thoracoabdominal segment as well as three-dimensional reconstructed arterial images, which is very helpful in diagnosing abdominal aortic aneurysms. 5.Magnetic resonance examination (MRA): It is the most advanced non-invasive imaging method, which does not need contrast agent and can clearly show the morphology of aortic aneurysm through computer imaging, and can obtain images of sagittal plane in addition to cross-section, which is extremely helpful for the diagnosis of coarctation aneurysm, etc. 6.Abdominal aortography: It used to be a routine examination, but now it is believed that there is often wall thrombus in the lumen of abdominal aortic aneurysm, and the contrast agent can only pass through the central part of the aneurysm and cannot reflect the whole picture. (3) those with large aneurysms, high upper segment of the mass, and those who suspect that the mass is above the renal artery and need to know the extent of the lesion and the involved vessels to decide the surgical plan; (4) those with multiple aneurysms, such as iliac artery aneurysm and femoral artery aneurysm. 7. In addition to this, in order to ensure the success of the surgery, a comprehensive understanding of the patient’s systemic condition is also necessary. This includes: echocardiography and pulmonary function tests to understand the cardiopulmonary function, isotope nephrogram to understand the renal function, myocardial nuclear imaging for patients with previous infarction, and coronary angiography if necessary. V. Treatment Treatment The main method of treatment for abdominal aortic aneurysm is surgical resection of abdominal aortic aneurysm + artificial vessel replacement, which is an anastomosis between the artificial vessel and the normal arterial wall near and distal to the abdominal aortic aneurysm (abdominal aorta and iliac/femoral artery wall). This is a relatively mature and classic surgical method, the advantage of which is the success rate of surgery Indications for surgery ① abdominal aortic aneurysm diameter greater than or equal to 4-6CM; ② aneurysm with pain and pressure pain; ③ follow-up confirmed that the aneurysm is rapidly increasing; ④ aneurysm has caused distal vascular embolism; ⑤ aneurysm compression of the gastrointestinal tract or other symptoms; ⑥ aneurysm diameter of less than 4CM, but the local Although the diameter of the aneurysm is less than 4CM, the aneurysm wall is thin and has the tendency to rupture. In recent years, the endovascular treatment of abdominal aortic aneurysm (interventional treatment) has become more and more accepted by the majority of patients. Interventional treatment of abdominal aortic aneurysm does not require opening the abdomen, but only a puncture (or a small incision) is made through the femoral artery at the root of the thigh, and under the guidance of a guidewire and catheter, a kind of overlapping stent is placed into the cavity of the aneurysm, and the two ends of the peritoneal stent are fixed to the normal abdominal aorta near the distal end of the aneurysm. This treatment has the advantages of less damage, faster recovery and fewer complications because it does not require opening the abdomen. It is especially suitable for patients with severe cardiac, pulmonary and renal insufficiency and those who are too weak to withstand general anesthesia and surgical blows. However, certain conditions are required for this treatment, and not all patients are suitable for this treatment. A series of comprehensive examinations must be performed before a specialist decides on the treatment method according to the patient’s specific situation. For abdominal aortic aneurysms smaller than 4 cm without a tendency to rupture, they can be followed up with an ultrasound once every 3 months to 6 months to observe the absence of growth and to control the blood pressure below 120/80 mmhg. VI. 1. The main cause of abdominal aortic aneurysm is atherosclerosis. To prevent the occurrence of this disease, we must start with the prevention of atherosclerosis, limit the intake of animal fat and high cholesterol food, eat more fruits and vegetables rich in vitamins, and keep the bowel movement smooth. 2, Quit smoking and alcohol to prevent atherosclerosis has certain benefits. Once the abdominal aortic aneurysm is formed, it is more important to strictly stop smoking and drinking. 3, at the same time to limit activities, should not be strenuous activities, avoid anger and impatience, control blood pressure below 120/80mmhg, in order to avoid the rupture of abdominal aortic aneurysm. 4.People with chronic obstructive pulmonary disease should pay attention to keeping warm and cold during the seasonal change, reduce the triggering factors of lung infection and avoid violent coughing. 5.Avoid constipation and all factors that increase the pressure in the thoracic and abdominal cavities as much as possible. 6. If there is a sudden onset of severe pain in the abdomen or lower back, it indicates the possibility of rupture of abdominal aortic aneurysm, and it is necessary to go to a hospital with vascular surgery in a hurry, otherwise it may be life-threatening.