The Safety and Efficacy of Flow Diversion versus Conventional Endovascular Treatment for Intracranial Aneurysms: A Meta-analysis of Real-world Cohort Studies from the Past 10 Years

Abstract

BACKGROUND: Although the flow diverter has advantages in the treatment of intracranial aneurysms, pooled studies that directly compare it with conventional endovascular treatments are rare. PURPOSE: Our aim was to compare the safety and efficacy of flow-diverter and conventional endovascular treatments in intracranial aneurysms.DATA SOURCES: We performed a comprehensive search of the literature using PubMed, EMBASE, and the Cochrane Database. STUDY SELECTION:We included only studies that directly compared the angiographic and clinical outcomes of flow-diverter and conventional endovascular treatments.DATA ANALYSIS: Random effects or fixed effects meta-analysis was used to pool the cumulative rate of short-and long-term angiographic and clinical outcomes.DATA SYNTHESIS: Eighteen studies with 1001 patients with flow diverters and 1133 patients with conventional endovascular treatments were included; 1015 and 1201 aneurysm procedures were performed, respectively. The flow-diverter group had aneurysms of a larger size (standard mean difference, 0.22; 95% CI, 0.03-0.41; P ¼ .026). There was a higher risk of complications in the flow-diverter group compared with the conventional endovascular group (OR, 1.4; 95% CI, 1.01-1.96; P ¼ .045) during procedures. The follow-up angiographic results of flow-diverter treatment indicated a higher rate of complete occlusion (OR, 2.55; 95% CI, 1.70-3.83; P , .001) and lower rates of recurrence (OR, 0.24; 95% CI, 0.12-0.46; P , .001) and retreatment (OR, 0.31; 95% CI, 0.21-0.47; P , .001).LIMITATIONS: Limitations include a retrospective, observational design in some studies, high heterogeneity, and selection bias. CONCLUSIONS:Compared with the conventional endovascular treatments, the placement of a flow diverter may lead to more procedure-related complications, but there is no difference in safety, and it is more effective in the long term.ABBREVIATIONS: BAC ¼ balloon-assisted coiling; CEV ¼ conventional endovascular; FD ¼ flow diverter; IA ¼ intracranial aneurysm; SAC ¼ stent-assisted coiling; SMD ¼ standard mean difference R apid technologic advances in endovascular treatments have been transforming the treatment modalities of intracranial aneurysms (IAs) in recent years. The Guglielmi detachable coil (Stryker), introduced in the early 1990s, provided an alternative to traditional surgical clipping in the treatment of IAs. 1 After that, reconstructive techniques such as balloon-assisted coiling (BAC) and stent-assisted coiling (SAC), were initially used. 2,3 Most recently, low-profile visualized intraluminal support (LVIS; MicroVention), a self-expandable, recyclable, braided stent, has also been widely adopted in clinical practice. 4 Compared with these standard and conventional stent methods, flow diverters (FDs), like the Pipeline Embolization Device (PED; Medtronic) approved by the US Food and Drug Administration in 2011, 5,6 have greater metal coverage and have broader indications for the treatment of complex aneurysms, such as large and giant ICA aneurysms and fusiform, disse...

Appraisal of the Flow Diversion Effect Provided by Braided Intracranial Stents

“…In this sense, flow diversion may be regarded as a continuous rather than binary variable that results in sufficient intra-aneurysmal stasis after endovascular treatment [ 25 ]. Although an exact definition of flow diversion is lacking, it is clearly known that progressive occlusion and minimal/no recanalization [ 26 , 27 , 28 ] are the hallmarks of flow diverters; that is, IAs treated with FDs are expected to occlude progressively and then maintain their occlusion during the follow-up [ 2 ].…”

“…With the advancements in braiding and stent technology, especially the evolution of braided intracranial stents, the durability of endovascular treatment improved. Finally, with the introduction of flow diverters (which are actually densely woven intracranial braided stents), the recurrence rates of angiographically eliminated aneurysms decreased to negligible rates [ 2 ]. Although the mechanism of complete aneurysm occlusion obtained with stent-assisted coiling (SAC) is a topic of ongoing research [ 3 ], current evidence suggests that flow remodeling effect [ 1 ] leading to thrombosis and reduction in shear stress [ 4 , 5 ] are involved in the healing process of aneurysms.…”

Reconstructive endovascular treatment for basilar artery trunk aneurysms: complications and clinical and angiography outcomes

“…This could promote progressive aneurysm occlusion over time. Flow diversion has a higher complete occlusion rate and a lower retreatment rate compared with traditional coil embolization, 19 20 and it produces more favorable angiographic and clinical outcomes than traditional stent-assisted coiling in patients with large or giant basilar trunk and vertebrobasilar junction aneurysms. 7 However, the effects of flow diverters could not be elucidated in this study, perhaps due to small aneurysm size and short follow-up time.…”

In reply

“…Without pretending at all that we now have updated our systematic review of the literature, we could point to other new reviews that have recently been published and that again show that treatment with any stent or flow-diverting stents have a considerably higher risk of complications than endovascular coiling. 5,6 We do welcome results of well-designed studies to substantiate or refute our recommendations. A change of recommendations should however be based on a properly performed search of the literature, to avoid selective referencing, showing that new, good quality evidence has become available.…”

“…Without pretending at all that we now have updated our systematic review of the literature, we could point to other new reviews that have recently been published and that again show that treatment with any stent or flow-diverting stents have a considerably higher risk of complications than endovascular coiling. 5,6…”