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

Abstract

Aim: 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.

Methods: 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.

Results: 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.

Conclusion: 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.