BACKGROUND: The management of unruptured @entity438 is controversial. Investigators from the International Study of @entity438 aimed to assess the natural history of unruptured @entity438 and to measure the risk associated with their repair. METHODS: Centres in the USA, Canada, and Europe enrolled @entity1 for prospective assessment of unruptured @entity439 . Investigators recorded the natural history in @entity1 who did not have surgery, and assessed morbidity and mortality associated with repair of unruptured @entity439 by either open surgery or endovascular procedures. FINDINGS: 4060 @entity1 were assessed-1692 did not have aneurysmal repair, 1917 had open surgery, and 451 had endovascular procedures. 5-year cumulative rupture rates for @entity1 who did not have a history of @entity510 with @entity439 located in internal carotid artery, anterior communicating or anterior cerebral artery, or middle cerebral artery were 0%, 2. 6%, 14 5%, and 40% for @entity439 less than 7 mm, 7-12 mm, 13-24 mm, and 25 mm or greater, respectively, compared with rates of 2 5%, 14 5%, 18 4%, and 50%, respectively, for the same size categories involving posterior circulation and posterior communicating @entity438 . These rates were often equalled or exceeded by the risks associated with surgical or endovascular repair of comparable lesions. @entity1 ' age was a strong predictor of surgical outcome, and the size and location of an @entity439 predict both surgical and endovascular outcomes. INTERPRETATION: Many factors are involved in management of @entity1 with unruptured @entity438 . Site, size, and group specific risks of the natural history should be compared with site, size, and age-specific risks of repair for each @entity1 .

Unruptured XXXX : natural history, clinical outcome, and risks of surgical and endovascular treatment.

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients', 'patient'] @entity439 :: ('MESH:D000783', 'Disease') :: ['aneurysms', 'aneurysm'] @entity510 :: ('MESH:D013345', 'Disease') :: ['subarachnoid haemorrhage'] @entity438 :: ('MESH:D002532', 'Disease') :: ['Unruptured Intracranial Aneurysms', 'artery aneurysms', 'intracranial aneurysms']
@entity438 :: (MESH:D002532,Disease) :: ['intracranial aneurysms']
