The CAESAR trial (Comparison of surveillance vs Aortic Endografting for Small Aneurysm Repair) was a multicentre randomised trial that addressed one of the most common clinical questions in vascular surgery: should we repair small abdominal aortic aneurysms early, or watch and wait?
Published in 2010, the trial randomised 360 patients with AAAs measuring 4.1 to 5.4 cm to either immediate EVAR or ultrasound surveillance with repair only if the aneurysm grew to 5.5 cm or became symptomatic.
The results were clear: at a median follow-up of 32 months, there was no difference in all-cause mortality or aneurysm-related mortality between the two groups. The rupture rate in the surveillance group was very low (0.6% per year), confirming that small aneurysms can be safely monitored.
Importantly, 62% of patients in the surveillance arm eventually required repair during follow-up, but delaying surgery did not increase operative risk or worsen outcomes. The quality of life was similar between groups throughout the study period.
CAESAR, together with the similar PIVOTAL trial, confirmed the 5.5 cm threshold for AAA repair that underpins current NICE guidelines and international practice. For trainees, this trial is essential reading for understanding the evidence base behind surveillance protocols and for the common viva question on small aneurysm management.