# Clinical characteristics and outcomes of surgery for renal artery aneurysms: analysis from a single institute in Japan

## TL;DR

This study examines the clinical features and surgical outcomes of renal artery aneurysms in Japan, finding they expand slowly and rarely rupture, with mild post-surgery complications.

## Contribution

The study provides new clinical insights into the natural history and surgical management of renal artery aneurysms in a Japanese cohort.

## Key findings

- Renal artery aneurysms have a low expansion rate of 0.055 mm/month on average.
- Egg-shell calcified aneurysms showed an even lower expansion rate of 0.0005 mm/month.
- Surgical interventions led to complications like renal infarction and bypass occlusion, but with mild renal impairment.

## Abstract

We investigated the clinical characteristics of renal artery aneurysm (RAA) and the outcome of surgical intervention.

The subjects of this retrospective analysis were 105 patients who were admitted to our department between 1999 and 2023.These 105 patients had a collective total of 151 RAAs.

The RAAs were localized unilaterally in 89 patients and bilaterally in 16 patients. The average age at diagnosis was 61.8 ± 12.4 years. The mean diameter on admission was 14.9 ± 7.0 mm. The expansion rate was 0.055 ± 0.46 mm/month (mean follow-up period: 53.1 months). “Egg-shell” calcification appearance was found for 21% of the RAAs, with a lower expansion rate (0.0005 ± 0.003 mm/month). Rupture occurred in one patient with a pseudoaneurysm. 20 aneurysms co-existed with other aneurysms, most commonly with splenic aneurysms (n = 10). Surgery was performed for a collective 34 RAAs in 24 patients, including 15 aneurysmectomies with or without bypasses, 8 aneurysmorrhaphies, 2 ex vivo aneurysm repairs, 1 coil embolization, and 1 stent graft insertion. Post-operative complications included renal infarction (n = 8) and bypass occlusion (n = 4), with the estimated glomerular filtration rate decreasing to 80% (range: 67–99%) and 76% (55–77%), respectively.

RAAs have low expansion rates and a minimal risk of rupture, particularly if they are of the “egg-shell” type. Post-operative adverse events included renal infarctions and bypass failure, with mild renal impairment.