Objective: The outcomes reported in the International Subarachnoid Aneurysm Trial (ISAT), a multicenter, prospective, randomized trial to directly compare surgical clipping with endovascular coiling as treatments for ruptured intracranial aneurysms, have been misinterpreted by many to indicate the superiority of coiling to surgical clipping in all instances. To better understand the results of ISAT and their implications for practice patterns, we compared the ISAT results with the results of other published studies regarding the treatment of ruptured intracranial aneurysms.
Methods: Data from 19 published studies were compared with each other and with ISAT results. Outcomes examined were overall rates of mortality, rebleeding, poor outcome (disability and death), procedural complication rates, and rates of reoperation and nontotal occlusion.
Results: In the 19 published studies, mean procedural complication rates were similar (surgical clipping, 11%; endovascular coiling, 9%); ISAT did not report procedural complications. ISAT rates were within the range of the other studies for overall mortality, total rebleeding, and poor outcome. Reoperation rates in the other studies were similar to those of ISAT (endovascular coiling, 12.5%; surgical clipping, 3.4%). The ISAT rate for less than 100% occlusion for endovascular coiling (6%) was below the range in the other studies (8.3-70.4%).
Conclusion: Discrepancies with the results of other published studies, procedural limitations in study design, and lack of some data endpoints and subgroup analysis raise concerns regarding extracting generalizations from the conclusions of ISAT. We think that the creation of a national registry would further the study of treatment of ruptured intracranial aneurysms.