Natural History and Chronological Growth Rate of Renal Artery Aneurysms.

: Renal artery aneurysm (RAA) is an uncommon disease, the natural course of which is still not well known. The objective of this study is to define factors that affect the growth rate of RAAs. : We retrospectively reviewed 32 aneurysms in 26 patients at our institute between January 2010 and March 2016. Basal demographics, comorbidities, reason for diagnosis, and details of the aneurysms and interventions were recorded. The chronological changes in the diameter of the RAA using multiplanar reconstructions of computed tomography images were measured and analyzed. : The baseline mean diameter was 20.1±8.4 mm (range: 9.9-41). The mean follow-up period was 3.13±2.1 y (range: 0.5-7.1). The median growth rate was 0.35 mm/y (interquartile range: 0.05, 0.62). The growth rate was slower when the initial diameter was <20 mm than when it was >20 mm (p=0.036). Also, whole-completed calcification was a significant factor for slower growth (p=0.016). We performed ex-vivo surgery in two cases and coil packing with stenting in one. No ruptures occurred during the study period. : Our results suggest that cases with an RAA diameter <20 mm do not require intervention. The interval period can be longer in whole-completed calcification types.