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International Subarachnoid Aneurysm Trial 2009: Endovascular Coiling of Ruptured Intracranial Aneurysms Has No Significant Advantage Over Neurosurgical Clipping

Bakker, Nicolaas A. MD, PhD; Metzemaekers, Jan D.M. MD, PhD; Groen, Rob J.M. MD, PhD; Mooij, Jan Jakob A. MD, PhD; Van Dijk, J. Marc C. MD, PhD

doi: 10.1227/01.NEU.0000368152.67151.73
Special Commentary

In the May 2009 issue of The Lancet Neurology, the 5-year follow-up results of the International Subarachnoid Aneurysm Trial (ISAT) were published. The authors concluded that, although the significant difference between coiling and neurosurgical clipping of ruptured intracranial aneurysms in terms of death and severe disability after 1 year has vanished (primary endpoint), coiling should still be favored over neurosurgical clipping because mortality rates significantly favored coiling. In this commentary, it is this particular conclusion that is challenged by combining data from previous ISAT publications with the current 5-year follow-up results. This modified intent-to-treat analysis clearly demonstrates that the significant advantage in terms of mortality in favor of the endovascularly treated patients is no longer present, with a hazard ratio of 0.80 in favor of endovascular treatment (95% confidence interval: 0.60–1.05; P = .10). Therefore, for everyday clinical practice and decision making, coiling and clipping are to be considered equivalent in the long term.

Department of Neurosurgery, University Medical Center Groningen, Groningen, The Netherlands

Reprint requests: Nicolaas A Bakker, MD, PhD, Department of Neurosurgery, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands. E-mail:

Received, September 9, 2009.

Accepted, December 27, 2009.

Copyright © by the Congress of Neurological Surgeons