A 14-year experience with 6 cm as a criterion for surgical treatment of abdominal aortic aneurysm

Background: It remains unclear when to recommend operation for an asymptoma tic abdominal aortic aneurysm (AAA). This study examined a prospective seri es of patients for whom standard criteria were applied. Methods: Some 584 consecutive patients with an AAA of diameter 3 cm or grea ter detected by ultrasonographic screening have been observed for up to 14 years. Repeat ultrasonographic examinations have been performed at interval s. Surgery was not considered unless the aneurysm measured 6 cm in diameter , expanded at a rate equivalent to at least 1 cm per year, caused the patie nt symptoms, or an iliac aneurysm was present that required treatment. Results: Operation was performed on 127 patients; the majority (80; 63 per cent) had an aneurysm that reached 6 cm in diameter. Use of the above crite ria prevented rupture in all but 24 (4 per cent) of the 584 patients over t he 14-year interval. Of these 24 patients, Il were unfit for planned surger y and eight declined operation or follow-up. Rupture in the five remaining patients (1 per cent) who were available for treatment compared favourably with the reported 30-day mortality rate for elective surgical treatment of 1.4-12 per cent. Conclusion: Repeated observation is preferable to surgical intervention unt il an aortic aneurysm measures 6 cm in diameter, expands by 1 cm per annum or causes symptoms.