Purpose: The purpose of this study was to clarify the treatment of patients with small abdominal aortic aneurysms (AAAs) less than 5 cm in diameter and those believed to be unfit for operation with AAAs 5 cm diameter or greater. Methods: Four hundred ninety two patients with AAAs less than 5 cm when first seen were entered in a prospective measurement program by ultrasonography or computed tomography scan (exclusively after 1988) every 6 months. A decision regarding operative fitness was made when the AAA was 5 cm. Patients then underwent operation if fit or continued follow-up if their AAA was larger than 5 cm but they were unfit. A further group of 91 patients with aneurysms 5 cm or greater when first seen but unfit for repair were entered in the prospective measurement program. Results: In the group with AAAs less than 5 cm at entry, operation was performed in 201 patients as a result of increase in AAA size to 5 cm or greater (157), AAA expansion of more than 0.5 cm in 6 months (24), or for other reasons (20). Of those with AAAs smaller than 5 cm at entry, 291 have not undergone operation at a mean follow-up of 42 months. Expansion was significantly related to aneurysm size at entry and was highest in the 4.5 to 4.9 cm group at 0.7 cm/year. In the group of patients deemed unfit for operation with 5 cm AAAs [as a graduate of the less than 5 cm group at entry (85 patients) or first seen with AAA greater than 5 cm (91 patients)], 10 ruptures have occurred. Of these patients with ruptured AAAs, six had AAA between 5.0 and 5.6 cm. Conclusions: Because of the risk of rupture demonstrated in our series in AAAs 5 cm or slightly greater and the progressive increase in expansion to a mean of 0.7 cm/year in those AAA between 4.5 and 4.9 cm at entry, recommendation for elective operation in patients with AAAs between 4.5 and 5.0 cm should be strongly considered in a fit patient.
Brown, P. M., Pattenden, R., Vernooy, C., Zelt, D. T., Gutelius, J. R., Cronenwett, J. L., … Hallett, J. W. (1996). Selective management of abdominal aortic aneurysms in a prospective measurement program. Journal of Vascular Surgery, 23(2), 213–222. https://doi.org/10.1016/S0741-5214(96)70265-3