Natural History of Small Abdominal Aortic Aneurysms

ABSTRACT

The operative treatment of abdominal aortic aneurysm (AAA) is generally recommended in ruptured AAA, symptomatic or rapidly expanding AAA, complicated AAA and atypical aneurysms, but there is a controversy in treatment of asymptomatic small-sized AAA. To determine the proper management plan, it is important to know the natural history of AAA, expansion rate and frequency or pattern of complications. There are several reports about the natural history of AAA in western population, but little has been reported in Koreans. Authors performed this study in order to analyze the natural history of small AAA, and to establish a guideline in the proper management of small AAA. PATIENTS & METHODS: Since January 1991, among the patients diagnosed as AAA at Seoul National University Hospital, we followed 15 patients whose aneurysm size was less than 6 cm without operation. In this study, we analysed the natural history of 11 cases with more than 6 months follow up; occurrence of symptoms, physical examinations, and aneurysm size measurement by ultrasound or CT every 6 months. RESULTS: All 11 patients were men, and the mean age was 63.9 years, ranging 54 to 75 years. According to the measurement of largest transverse diameter, mean expansion rate for 6 months was 0.17 0.138 cm. Follow-up period ranged 6~84 months and the median duration was 30 months. Expansion rate according to the initial size was 0, 0.246, 0.178, 0.1 cm/6 months respectively in group A (4.0 cm; 1 case). There was no rupture, aneurysm-related complication, nor death during the follow-up period. We performed elective operations in 2 cases, first case due to aneurysmal expansion over 6 cm, and the other due to severe anxiety of the patient for rupture. CONCLUSIONS: It may be a safe treatment discipline to follow up small AAA patients with sono-guided size measurement and elective operation in selected cases.