Table 1 Selection criteria

a.

At least one documented subarachnoid aneurysm, never ruptured

b.

Patient aged 18 or older

c.

Life expectancy more than 10 years

Exclusion criteria

a.

Patients with recent (less than 3 months) intracranial haemorrhage

b.

Lesion characteristics unsuitable for endovascular treatment

c.

Patients with a single extradural aneurysm

d.

Aneurysms <3 mm or giant aneurysms (≥25 mm)

e.

Patients with a poor outcome (Rankin scale ≥3) after the rupture, surgical or endovascular treatment of another aneurysm

f.

Patients with incompletely treated aneurysms that have previously ruptured

g.

Patients with associated arteriovenous malformations

h.

Patients with new severe progressive symptoms in relationship with the aneurysm (sudden onset, severe persisting headaches suggestive of impending rupture, third-nerve palsy, mass-effect)

i.

Patients with previous intracranial haemorrhage from unknown aetiology

j.

Patients with multiple unruptured aneurysms in whom surgical clipping of one or many aneurysms is planned in addition to endovascular management

k.

Patients with absolute contraindications to anaesthesia, endovascular treatment, or administration of contrast material, including low-osmolarity agents or gadolinium

l.

Pregnant patients

m.

Patients unable to give informed consent