Safety of coil embolisation in small (smaller than 5 mm) unruptured intracranial aneurysms: A retrospective multicentre analysis

Abstract

BackgroundRisk-benefit analysis results for the treatment of unruptured aneurysms smaller than 5 mm are controversial. This study aimed to identify the outcomes and complication associated with treating such unruptured aneurysms. MethodsThis was a retrospective study of 165 consecutive patients who underwent endovascular procedures for unruptured cerebral aneurysms of a maximum diameter 5 mm between January 2018 and March 2021. Patient background, aneurysm characteristics, adjuvant technique, volume embolization rate (VER), symptomatic complications, and modified Rankin Scale (mRS) scores were examined. ResultsSixty patients with sufficient data were included in the study. The mean age was 62.1 ± 14.6 years, and the median follow-up period was 12 months. The mean maximum diameter was 4.16 ± 0.63 mm, the neck diameter was 2.73 ± 0.82 mm, and 90% of patients had anterior circulation. Complete occlusion was achieved in 34 cases (57.6%). Although there were no intraoperative ruptures, complications were observed in four patients (6.7%), and one patient (1.7%) had worsened mRS score. Only one patient (1.7%) required retreatment. The first coil VER was independently associated with complete occlusion after endovascular treatment. Univariate analysis of complications showed an association between hypertension, hyperlipidaemia, and the estimated glomerular filtration rate. ConclusionsNo patient experienced mRS score deterioration, and only one patient developed permanent disability due to ischemic complications; hence, we could safely treat small unruptured aneurysms. Complications are not related to procedural factors such as coiling adjuvant technique. However, lifestyle-related diseases are related to complications, and we suggest that physicians should remain vigilant of the indication for coiling when treating patients with underlying diseases.