ISAT‐2.

Trial name or title	International Subarachnoid Aneurysm Trial 2
Methods	Method of randomisation: centralised minimisation procedure via web platform Minimisation criteria to be balanced between groups: age ≥ 70 years, WFNS grade > III, aneurysm size > 3 cm, posterior circulation location of aneurysm
Participants	Target sample size: 1896 participants, expected loss to follow‐up < 10% Listed location countries: Canada, Spain, US Inclusion criteria Aged ≥ 18 years ≥ 1 documented, intradural, intracranial aneurysm, ruptured within last 30 days SAH WFNS ≤ grade IV Participant and aneurysm considered appropriate for either surgical or endovascular treatment by the treating team Exclusion criteria People with absolute contraindications administration of contrast material (any type) People with AVM‐associated aneurysms Aneurysm located at basilar apex
Interventions	Surgical management of the ruptured aneurysm Endovascular management (including use of adjunctive techniques such as flow‐diverting stents and WEB devices in addition to coiling)
Outcomes	Primary outcome Poor clinical outcome (mRS > 2) at 12 months Secondary outcomes Aneurysm haemorrhage following treatment within 12 months Failure of aneurysm occlusion using the intended treatment modality within 48 hours of attempted treatments Overall mortality and morbidity from all causes at 1 and 5 years Occurrence of major aneurysm recurrence within 12 months (SD 2 months) Peritreatment hospitalisation > 20 days or discharge to a location other than home, or both Occurrence of aneurysm rerupture following randomisation but before treatment initiation
Starting date	October 2012
Contact information	clinicaltrials.gov/ct2/show/record/NCT01668563
Notes	Estimated primary completion date: 2023

AVM: arteriovenous malformation; mRS: modified Rankin scale; SAH: subarachnoid haemorrhage; WEB: Wowen EndoBridge; WFNS: World Federation of Neurological Surgeons subarachnoid haemorrhage grading scale.