Natural History of True Renal Artery Aneurysms: A Multi-Centre Retrospective Cohort Study and Proposed Algorithm for...

To identify the pattern of growth of true renal artery aneurysms (RAA) in a multicentre cohort and to propose an algorithm for the follow-up of asymptomatic RAA.

A retrospective review of all patients identified to have true RAA with subsequent follow-up cross-sectional imaging at three centres over a 15-year period was performed. Aneurysm maximal diameter was measured on initial and latest imaging and growth pattern assessed by two radiologists in consensus.

In total, 155 patients with 171 aneurysms were identified with follow-up imaging. Mean initial aneurysm size was 1.27 cm (range 0.3-3.4 cm) with a mean follow-up time of 61.08 months (range 12-182.5 months). 159 (93%) aneurysms remained stable in size over time. Overall mean growth rate was 0.015 cm/y. RAA ≤ 1.5 cm at diagnosis were associated with significantly lower mean growth rates (0.01 cm/year; p = 0.0059). No RAA rupture occurred during the follow-up period.

The present study demonstrates an indolent course of RAA with no ruptures reported and stability over time demonstrated in 93% of a multicentre cohort. These findings are in agreement with multiple other published studies. A positive impact on cost, equity of resources, and cumulative radiation exposure with rationalisation of RAA surveillance warrants its consideration, particularly in low risk cohorts.