ArticlesUnruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment
Introduction
Unruptured intracranial aneurysms are diagnosed with greater frequency as imaging techniques improve. The management of unruptured intra-cranial aneurysms remains controversial because of incomplete and conflicting data about the natural history of these lesions and the risks associated with their repair.1, 2, 3, 4, 5, 6, 7, 8, 9
Results of phase 1 of this study have been reported pre-viously,1 and include a retrospective study of the natural history and a prospective assessment of morbidity and mortality associated with surgical repair of unruptured aneurysms. Here, we include only prospective data on the natural history of unruptured intracranial aneurysms, the clinical outcomes of endovascular treatment, and a more comprehensive assessment of the risks of surgical treatment. With these combined data, the study aim is to provide information about the magnitude and determinants of the risks associated with the natural history and repair of unruptured intracranial aneurysms.
Section snippets
Patients
Study coordinators identified eligible patients prospectively from people who were diagnosed between 1991 and 1998, and visited International Study of Unruptured Intracranial Aneurysms (ISUIA) centre. They used the system's central inpatient and outpatient admission records, and records from departments of radiology, neurosurgery, and neurology to identify eligible patients.
Patients were eligible for enrolment if they had at least one unruptured intracranial aneurysm, whether or not they had
Results
Between December, 1991, and December, 1998, 4060 patients were enrolled from 61 centres in the USA, Canada, and Europe. 2035 (50%) patients were identified before 1996; however, the accrual of cases was greatest in 1997 and 1998 when 1775 (43%) joined the study.
Table 1 shows the baseline characteristics of patients in the unoperated and operated cohorts. Conditions that led to the diagnosis of unruptured intracranial aneurysms did not differ substantially in the unoperated and operated cohorts (
Discussion
The idea that the natural history of unruptured intracranial aneurysms cannot be extrapolated from evaluation of patients with ruptured aneurysms is reinforced by the natural history data from this study. These data also indicate that aneurysm size (especially inpatients who have not had previous sub-arachnoid haemorrhage) and location have a significant role in determining the risk of future rupture. Early rupture rates in the prospective group were higher than in the previously published
References (15)
- et al.
“Mini-mental state”. A practical method for grading the cognitive state of patients for the clinician
J Psychiatr Res
(1975) Unruptured intracranial aneurysms-risk of rupture and risks of surgical intervention
N Engl J Med
(1998)- et al.
Mortality and morbidity of surgery for unruptured intracranial aneurysms-a meta analysis
Stroke
(1998) - et al.
Prevalence and risk of rupture of intracranial aneurysms: a systematic review
Stroke
(1998) - et al.
Unruptured intracranial aneurysms
N Engl J Med
(1999) - et al.
Treatment of intracranial aneurysms by embolization with coils
Stroke
(1999) - et al.
Recommendations for the management of patients with unruptured intracranial aneurysms: a statement for healthcare professionals from the Stroke Council of the American Heart Association
Stroke
(2000)
Cited by (0)
Investigators listed at end of report