What is the long-term outcome for patients with very small abdominal aortic aneurysms?

Objective: To determine the long-term outcome for patients with abdominal aortic aneurysms (AAA) less than 4 cm in AP diameter (very small AAA). Design: Population-based screening study. Materials and methods: One hundred and forty-two patients who had AAA less than 4 cm at presentation were assessed by ultrasound at intervals of 6-12 months. The records of these patients were reviewed. Results: During the period of follow-up the median annual growth rate for aneurysms while under 3.0 cm was 1 mm, rising to 2 mm when between 3.0 and 3.9 cm, and 3 mm when between 4.0 and 4.9 cm in diameter. Elective aneurysm repair was undertaken when aneurysms exceeded the threshold value, which itself increased from 4 cm to 5.5 cm in the 9 years of follow-up. Move patients died with their aneurysm (n=35) then underwent surgery (n=23). There was one perioperative death, and three unrelated late deaths after resection. One aneurysm ruptured in a patient who had refused follow-up 5 years previously. Conclusions: This study suggests that aneurysms less than 4.0 cm diameter are relatively benign, and questions the appropriateness of early intervention.