Trials and tribulations: An evidence-based approach to aneurysm treatment

Since the introduction of embolic coils in the early 1990s, endovascular treatment has gained much traction for use when treating ruptured and unruptured intracranial aneurysms. Three prospective studies have been conducted comparing endovascular coil embolization versus clipping for ruptured intracranial aneurysms. The first study took place in Finland and was the first head-to-head look at treating ruptured aneurysms by either endovascular coiling or surgical clipping. Results from this study suggested better functional outcome after endovascular treatment than surgery at the expenses of higher rates of incomplete aneurysm occlusion. The second largest and only multicenter study was the International Subarachnoid Aneurysm Trial (ISAT). The ISAT took place across Europe and was the first large-scale comparison between endovascular and surgical treatments. The results from this study caused a major opinion shift across the world in regards to optimal treatment of ruptured aneurysms. Additionally, the quantity of data from this study allowed for many subgroup analyses to be made. However, to assess the generalizability of the ISAT study, the Barrow Neurological Institute investigators conducted a single-center study. The intent of this latter study was to remove any potential bias and preselection by enrolling every consenting patient that presented with the designated pathology without any exclusion. However, this enrollment strategy resulted in a high percentage of patients with aneurysms not suitable for endovascular therapy being assigned to the coil group which in turn resulted in a high rate of turn over from the endovascular to the surgical arm of the study. Despite, these limitations, this latter trial presented similar results as the Kuopio and ISAT. Although each of these trials was not methodologically flawless, the combined results from all three suggest that endovascular treatment of ruptured aneurysms suitable for this treatment strategy results in quicker recovery and better functional outcomes at one year at the expenses of lower rates of complete aneurysm obliteration frequently requiring retreatment.