Objective: To delineate the natural history of infrarenal aortic aneurysms with respect to growth rate.
Methods: A referral based series of 233 patients with abdominal aortic aneurysm was serially assessed by abdominal ultrasound.
Results: The mean age was 71 years and the median follow up 26 months (range 6-146). The mean growth rate of the series was 3.2mm/year. Division of the initial size into those less than 41 mm (128 patients), between 41-60 mm (92 patients) and those above 60 mm (13 patients) in AP diameter showed mean growth rates per year were 2.6 mm/year, 4.1 mm/year and 6.5 mm/year. Examination of the relationship between aneurysm size and subsequent growth rate over the whole study period revealed a rank correlation of 0.19 (p = 0.002). Aneurysms were also observed to expand at an erratic rate both in terms of time and size.
Conclusions: When the initial decision is to observe the patient, serial ultrasound examinations facilitate later judgements on the balance of risks in relation to surgical treatment.