Flow Diversion in Ruptured Intracranial Aneurysms: A Meta-Analysis

BACKGROUND:Flow diversion is now an established technique to treat unruptured intracranial aneurysms not readily amenable to endovascular coil embolization or open microsurgical occlusion. The role of flow-diverting devices in treating ruptured aneurysms is less clear.PURPOSE:To estimate rates of angiographic occlusion and good clinical outcome in patients with ruptured intracranial aneurysms treated with flow-diverting devices.DATA SOURCES:Systematic review of Ovid MEDLINE, PubMed, Cochrane databases, and EMBASE from inception to December 2015 for articles that included ruptured aneurysms treated with flow diversion.STUDY SELECTION:One hundred seventy-two records were screened, of which 20 articles contained sufficient patient and outcome data for inclusion.DATA ANALYSIS:Clinical and radiologic characteristics, procedural details, and outcomes were extracted from these reports. Aggregated occlusion rates and clinical outcomes were analyzed by using the Fisher exact test (statistical significance, α = .05).DATA SYNTHESIS:Complete occlusion of the aneurysm was achieved in 90% of patients, and favorable clinical outcome was attained in 81%. Aneurysm size greater than 7 mm was associated with less favorable clinical outcomes (P = .027). Aneurysm size greater than 2 cm was associated with a greater risk of rerupture after treatment (P < .001).LIMITATIONS:Observational studies and case reports may be affected by reporting bias.CONCLUSIONS:Although not recommended as a first-line treatment, the use of flow diverters to treat ruptured intracranial aneurysms may allow high rates of angiographic occlusion and good clinical outcome in carefully selected patients. Aneurysm size contributes to treatment risk because the rerupture rate following treatment is higher for aneurysms larger than 2 cm.

Endovascular treatment of intracranial aneurysms with detachable coils was first described in 1991¹ and has since become an established method of aneurysm treatment. The International Study of Unruptured Intracranial Aneurysms² and Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms (ATENA)³ demonstrated the effectiveness and relative safety of endovascular coiling for unruptured aneurysms. Similarly, the International Subarachnoid Aneurysm Trial (ISAT), the Barrow Ruptured Aneurysm Trial, and other trials^4–7 have demonstrated the effectiveness and relative safety of endovascular coiling in ruptured aneurysms.In recent years, flow diverters (FDs) have emerged as a new endovascular treatment option for intracranial aneurysms. FDs are a reconstructive treatment in which altered flow within an aneurysm induces gradual remodeling and eventual thrombosis of the aneurysm. Several studies have demonstrated good safety and efficacy of FDs for the treatment of unruptured intracranial aneurysms,^8–17 though the safe use of these devices requires the use of dual antiplatelet therapy.^18–20Understandably, the need for antiplatelet medications and the delayed nature of aneurysm thrombosis have tempered enthusiasm for using FDs for ruptured aneurysms. Nevertheless, several reports have described the use of FDs to treat recently ruptured aneurysms, particularly those that are difficult to treat by other endovascular or open microsurgical techniques.In this meta-analysis, we review the outcomes associated with the use of FDs for the treatment of ruptured intracranial aneurysms. Specifically, we review aneurysm characteristics and endovascular treatment strategies in relation to the rates of angiographic occlusion and good clinical outcome, with the overall goal of guiding FD use in ruptured aneurysms when other treatment options are not viable.