BACKGROUND: Two types of treatment are being used for patients with ruptured 
intracranial aneurysms: endovascular detachable-coil treatment or craniotomy and 
clipping. We undertook a randomised, multicentre trial to compare these 
treatments in patients who were suitable for either treatment because the 
relative safety and efficacy of these approaches had not been established. Here 
we present clinical outcomes 1 year after treatment.
METHODS: 2143 patients with ruptured intracranial aneurysms, who were admitted 
to 42 neurosurgical centres, mainly in the UK and Europe, took part in the 
trial. They were randomly assigned to neurosurgical clipping (n=1070) or 
endovascular coiling (n=1073). The primary outcome was death or dependence at 1 
year (defined by a modified Rankin scale of 3-6). Secondary outcomes included 
rebleeding from the treated aneurysm and risk of seizures. Long-term follow up 
continues. Analysis was in accordance with the randomised treatment.
FINDINGS: We report the 1-year outcomes for 1063 of 1073 patients allocated to 
endovascular treatment, and 1055 of 1070 patients allocated to neurosurgical 
treatment. 250 (23.5%) of 1063 patients allocated to endovascular treatment were 
dead or dependent at 1 year, compared with 326 (30.9%) of 1055 patients 
allocated to neurosurgery, an absolute risk reduction of 7.4% (95% CI 3.6-11.2, 
p=0.0001). The early survival advantage was maintained for up to 7 years and was 
significant (log rank p=0.03). The risk of epilepsy was substantially lower in 
patients allocated to endovascular treatment, but the risk of late rebleeding 
was higher.
INTERPRETATION: In patients with ruptured intracranial aneurysms suitable for 
both treatments, endovascular coiling is more likely to result in independent 
survival at 1 year than neurosurgical clipping; the survival benefit continues 
for at least 7 years. The risk of late rebleeding is low, but is more common 
after endovascular coiling than after neurosurgical clipping.