EditorialThe Unruptured Intracranial Aneurysm Study-II: a critique of the second study
Section snippets
Theoretical bases of natural history studies
In performing a natural history study for a clinical disease process, there are several principles involved. First, there is assumed to be a universe of patients who have that disease, in this case unruptured intracranial aneurysms. This universe of patients contains those with single or multiple unruptured aneurysms, aneurysms that are unruptured at the time of another aneurysm rupture, aneurysms at all locations, aneurysms of all sizes and in patients of all ages and states of health. There
Basis of selection for the ISUIA-II report
In the ISUIA-II report [9], the investigators wanted to determine prospectively the rupture rate of the sample of patients they included in their study. Because the study is prospective it does not have the flaws of a study that looks back at the remaining patients who have survived with unruptured aneurysms, a retrospective study. The investigators enlisted patients in centers in North America and Europe. Other parts of the world were not represented. The patients included were those with
Results
In the unoperated and uncoiled group (no surgery group) there were 1,692 patients of whom 1,077 had no previously ruptured aneurysm and 615 who had a previously ruptured aneurysm at another site. “Patients were removed from follow-up if they had treatment (410 had subsequent surgery and 124 had endovascular treatment), as were those who died (193 patients)” [9]. What does this statement mean? To me, it means that in the group of patients we are supposed to be following for natural history,
Discussion
So, what have we learned from this presumed multimillion dollar study with over 60 centers and more than 100 neuroscientists who were involved? To me, not much. Why? What data am I going to use from this study that will help me with my next patient who has an unruptured aneurysm? The sample of patients with unruptured intracranial aneurysms from the universe of patients with unruptured intracranial aneurysms is so selected and super selected again that I do not know what patient group I am
Conclusion
This is my analysis of this ISUIA-II study. I am unimpressed with the study and find the data of no use to me for all the reasons I stated. The morbidity and mortality statistics for surgical treatment that include cognitive and functional outcomes are helpful for comparing with no treatment options. You have to decide what you think 2, 6.
References (10)
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(2002)Unruptured intracranial aneurysmsnatural history, clinical outcome, and risks of surgical and endovascular treatment
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The diameter-cube hypothesisa new biophysical model of aneurysm rupture
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Cited by (6)
Clipping versus coiling for intracranial aneurysms
2014, Neurologia i Neurochirurgia PolskaCitation Excerpt :Down to the fact that the epidemiologic data: incidence of bleeding and the prevalence of the aneurysms have ground basis, such a low probability of rupture of small aneurysms that was claimed by the ISUIA could be regarded as unreliable. It was noticed that the inclusion of patients had been a result of a careful selection and did not reflect the profile of patients with aneurysms of the general population [31,32]. Only patients who had not undergone treatment after neurosurgical assessment were qualified for the observation.
Factors affecting formation and rupture of intracranial saccular aneurysms
2014, Neurosurgical ReviewBetter outcomes with treatment by coiling relative to clipping of unruptured intracranial aneurysms in the United States, 2001-2008
2011, American Journal of NeuroradiologyEndovascular treatment of intracranial aneurysms
2010, Imaging in MedicineTreatment related morbidity of unruptured intracranial aneurysms: Results of a prospective single centre series with an interdisciplinary approach over a 6 year period (1999-2005)
2007, Journal of Neurology, Neurosurgery and Psychiatry