Table 4.

Summary of large studies evaluating the endovascular management of unruptured cerebral aneurysms.

Study	Important findings
International Study of Unruptured Intracranial Aneurysms (ISUIA) [12]	The 1-year morbidity rate was 6.4% and the mortality rate was 3.1% in 451 patients treated with endovascular coiling. The risk of poor outcome with endovascular procedure was higher with aneurysm diameter greater than 12 mm and posterior circulation location
Meta-analysis by Naggara et al. [20]: retrospective analysis of 97 studies from 2003 to 2011 with 7172 patients	Mortality rate of 1.8% and overall unfavorable outcomes rate (including death) of 4.7%. Endovascular treatment became safer over time with reduction in the rate of poor outcomes from 5.6% before 2000, 4.7% between 2001 and 2003, and 3.1% after 2004. Risk of unfavorable outcomes was 4.9% with coil embolization, 8.1% with liquid embolization agents, and 11.5% with flow diversion
Analysis of treatment by endovascular approach of nonruptured aneurysm (ATENA) by Pierot et al. [21]: prospective study on 739 unruptured aneurysms (<15 mm) treated in 27 centers in Canada and France	Morbidity and mortality at 1 month were 1.7% and 1.4%, respectively. Complications included intraoperative rupture rate of 2.6%, device-related complication rate of 2.9%, and thromboembolism rate of 7.1%
Murayama and colleagues [22]: retrospective study of 916 unruptured aneurysms treated with coil embolization	Rate of recanalization was 20.9%. The recanalization rate for small aneurysms (<10 mm) with narrow necks (<4 mm) was 5.1%, whereas, in small aneurysms with wide necks (>4 mm), it was 20.0%. The recanalization rate was 35.0% in large aneurysms (11–25 mm) and 59.1% in giant aneurysms (>25 mm)
Benes and colleagues [23]:  analysis of 151 unruptured aneurysms treated with coil embolization in 131 patients	Combined morbidity and mortality rate of 1.5% at 6 months. Thromboembolic complication rate of 7.6%