O-002 Flow diversion vs bypass surgery for complex aneurysms treatment: results of a randomized clinical trial

Abstract

<h3>Background</h3> Complex aneurysms are ones with a broad neck (dome/neck ratio &lt; 2), with no neck (fusiform), partially thrombosed, with side branching, or giant ones. The prevalence of these lesions ranges from 5 to 14.4% of all anterior circulation aneurysms. There is no universal strategy for complex aneurysm treatment, so the choice of surgical technique is based upon surgeon experience and preference. <h3>Objective</h3> To reveal whether clinical outcomes of flow diversion are superior to bypass surgery in the treatment of anterior circulation complex aneurysms. <h3>Methods</h3> An open, prospective, randomized, parallel-group, multicenter study of complex aneurysms treatment (clinicaltrials.gov NCT03269942) was conducted. The patients who met inclusion criteria were randomized into 2 groups with 1:1 allocation (55 patients each) to undergo flow diverter (FD) implantation or bypass surgery, respectively. Clinical examination and DSA were performed in 6 and 12 months to assess primary (clinical outcome by mRS score) and secondary endpoints (aneurysm occlusion, reoperation rate). <h3>Results</h3> Favorable clinical outcome was maintained in 52 patients (94.5%) from the FD group during 12 months follow-up. In the bypass group were 39 (70,9%) patients with favorable outcomes (p = 0.001). The morbidity and mortality rates were 5.5% and 1.8% for the FD group and 25.4% and 3.6% - for the bypass one. Complete aneurysm occlusion in 6 months was achieved in 46.3% of the patients from the FD group and in 94.3% from the bypass one (p &lt; 0.0001). The occlusion rate in 12 months was 64.8% and 98.1% for the FD and bypass groups, respectively (p &lt; 0.001). There were no significant differences between groups in the rate of hemorrhagic complications (p = 0.297), but an incidence of ischemic complications was higher in the bypass group (p= 0.004). <h3>Conclusion</h3> The study has demonstrated superior clinical outcomes for flow diversion in comparison with bypass surgery in treatment of complex aneurysms. At the same time, being associated with a significantly lower early obliteration rate, flow diversion put patients at risk of prolonged dual antiplatelet regimen and delayed rupture. <h3>Disclosures</h3> <b>R. Kiselev:</b> None. <b>D. andrey:</b> None. <b>K. Orlov:</b> None.