OBJECTIVES: Wide-necked bifurcation aneurysms (WNBAs) pose unique challenges for treatment via traditional endovascular approaches, due to the risk of coil herniation and the need to preserve patency in both parent and daughter vessels. The purpose of this study was to summarize published data associated with the occlusion of WNBAs via single and dual stent-assisted coil embolization.

METHODS: A systematic literature review was conducted using PubMed, Google Scholar, Ichushi, Cinii, and Medical Online databases. Studies were eligible for inclusion if they reported outcomes of interest for >10 patients between 1-Jan-2004 and 31-July-2018 in English or Japanese, and were not reviews, commentary, or case reports. At least 80% of the study population must have received endovascular treatment for unruptured or non-emergent WNBAs.

RESULTS: Thirty-five publications (1,571 patients) were identified. Ten were non-randomized comparative studies while 25 were single-arm. Twenty utilized dual stent-assisted approaches (e.g., Y-stenting) and 15 utilized a single stent. Commonly reported outcomes included: complete/adequate occlusion, mortality, peri-procedural complications, technical success, recanalization, retreatment, and the modified Rankin Scale. No economic data or patient-reported outcome measures were described.

With the exception of one study, assessment of clinical success was performed by the investigator rather than an independent core laboratory. Substantial variation was observed in occlusion rates for both single and dual stent-assisted treatment. For the single stent subgroup, complete occlusion ranged from 12.1-94.1% (immediate; n=9), 66.7-86.5% (6-12M; n=2), and 70.3-89.3% (12-24M; n=7). For the dual stent subgroup, complete occlusion ranged from 25.4-90.0% (immediate; n=10), 60.0-95.7% (6-12M; n=7), and 62.5-85.9% (12-24M; n=5). Retreatment and mortality were similarly reported with substantial variations.

CONCLUSIONS: The evidence base for conventional endovascular treatments for WNBAs consists of low- to medium- quality studies with a limited scope of reported outcomes. As new therapies become available, conventional treatment approaches need to be better understood as an objective performance benchmark.