Impact of International Subarachnoid Aneurysm Trial results on treatment of ruptured intracranial aneurysms in the United States

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The utilization of endovascular treatment for ruptured intracranial aneurysms is expected to change since the publication of the International Subarachnoid Aneurysm Trial (ISAT) in 2002. The authors performed this analysis to determine the impact of ISAT results on treatment selection for ruptured intracranial aneurysms and associated in-hospital outcomes using nationally representative data.


We determined the national estimates of treatments used for ruptured intracranial aneurysms and associated in-hospital outcomes, length of stay, mortality, and cost incurred using the Nationwide Inpatient Survey (NIS) data. The NIS is the largest all-payer inpatient care database in the US and contains data from 986 hospitals approximating a 20% stratified sample of US hospitals. All the variables pertaining to hospitalization were compared between 2000–2002 and 2004–2006, and in-hospital outcomes were analyzed using multivariate analysis.


In the 3-year periods prior to and after the ISAT, there were 70,637 and 77,352 admissions for ruptured intracranial aneurysms, respectively. There was a significant increase in endovascular treatment after publication of the ISAT (trend test, p < 0.0001) The in-hospital mortality for ruptured intracranial aneurysm admissions decreased from 27% to 24% (odds ratio [OR] 0.89, 95% CI 0.83–0.96, p = 0.003) after the publication of the ISAT. The cost of hospitalization after adjusting for procedures practices was not significantly higher after the publication of the ISAT ($21,437 vs $22,817, p < 0.89), but cost of hospitalization was higher in the post-ISAT period for patients undergoing endovascular procedure.


The results of the ISAT have been associated with a prominent change in practice patterns related to the treatment of ruptured aneurysms. The cost of hospitalization has increased and the mortality has decreased, presumably due to a larger proportion of patients receiving any treatment and endovascular treatment.

Abbreviations used in this paper: HCUP = Healthcare Cost and Utilization Project; ICD-9-CM = International Classification of Disease, 9th Revision, Clinical Modification; ISAT = International Subarachnoid Aneurysm Trial; LOS = length of stay; NIS = Nationwide Inpatient Survey; SAH = subarachnoid hemorrhage.

Article Information

Address correspondence to: Adnan I. Qureshi, M.D., Department of Neurology, University of Minnesota, 12-100 PWB, 516 Delaware Street SE, Minneapolis, Minnesota 55455. email:

Please include this information when citing this paper: published online July 23, 2010; DOI: 10.3171/2010.6.JNS091486.

© AANS, except where prohibited by US copyright law.



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    Bar graph demonstrating the yearly SAH admissions (NIS 2000–2006).

  • View in gallery

    Bar graph demonstrating the yearly distribution of treatments performed between no treatment, endovascular, and surgical treatment among SAH admissions (NIS 2000–2006).



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