An aneurysm is defined as a permanent restrictive dilatation of the arterial vessel wall exceeding 50% of the normal vessel diameter. Therefore, a precise definition of abdominal aortic aneurysm (AAA) would require calculation of the ratio of normal to dilated abdominal aorta in the same individual, with correction for influencing factors such as age, sex, race and body surface area. Usually, AAA can be diagnosed with an abdominal aortic diameter of more than 3 cm. 1. Incidence The occurrence of AAA is related to many epidemiological factors, such as age, gender, race, family history, and smoking. The incidence of AAA is correspondingly higher in people of advanced age, males, Caucasians, positive family history, and long-term smokers. The Malma Hospital in Sweden has performed autopsies on all patients who died during hospitalization and found that the incidence of AAA gradually increases with age in people over 50 years of age and can reach 5.9% in male patients over 80 years of age [1]. 2. Etiology The biological mechanisms of aneurysm development are complex, and genetic susceptibility, atherosclerosis and various proteases have been shown to be directly related to its occurrence. All etiologies ultimately manifest as degenerative changes in the middle layer of the aorta, followed by dilatation under blood flow pressure to form aneurysms. 2.1 Genetic susceptibility Several studies have shown that the occurrence of aneurysms is closely related to genetics. A 9-year follow-up of foreign patients with AAA found that aneurysms of all sites also occurred in 15% of the immediate family members of AAA patients, compared with 2% of the control group, P.