Introduction Wide neck aneurysms (WNAs) are more challenging to treat compared to narrowneck aneurysms, requiring more advanced techniques. The Wide Neck/EVERRUN Registry compared endovascular versus microsurgical techniques for both unruptured and ruptured aneurysms.

Purpose To utilize a previously collected multicenter WNA registry and compare treatment strategy (EVT vs. MS) and angiographic results in ruptured vs. unruptured WNAs.

Methods WNAs included in this registry were saccular and not previously treated. WNA definition was aneurysm neck greater than or equal to 4 mm or dome-to-neck-ratio (DTNR) less than 2. Differences in treatment strategy (EVT vs. MS) and angiographic results were the primary outcomes of the study. The angiographic outcome was assessed immediately following treatment and again at last follow-up using the Raymond scale with core lab review (adequate occlusion: RR 1-2). Statistical significance was set at an alpha level of p<0.05. All analysis was performed using R(v. 4.2.1)

Results The analysis included 310 WNA (87 ruptured (R) aneurysms vs. 223 unruptured (U)). There were no significant differences in the rate of EVT vs. MS between ruptured (R) vs. unruptured (U) aneurysms (Clipping, R: 36.8%, U: 37.7%). Amongst EVT, ruptured WNA were more commonly treated with stand-alone coiling (R: 27.6%, U: 5.8%) and balloon-assisted coiling (R: 32.2%, U: 10.8%) and unruptured aneurysms were more commonly treated with flow diversion (R: 1.1%, U: 22.9%) and stent-assisted coiling (R: 2.3%, U: 21.5%)(p<0.05 for all). Ruptured aneurysms had higher rates of adequate angiographic occlusion after initial treatment (R: 88.5%, U: 74.3%)(p<0.05). There was no difference in final adequate occlusion at follow-up (R: 90.1%, U: 90.7%). There were significantly higher rates of WNA retreatment in the ruptured cohort (R: 14.3%, U: 3.1%)(p<0.05). There were more procedural complications in the treatment of ruptured WNA than unruptured (R: 28.7%, U: 17%)(p<0.05). Expectedly, rates of good mRS (0-2) at one year were higher in unruptured WNA patients compared to ruptured (R: 72.8%, U: 90.3%)(p<0.05)

Conclusions When treating WNAs, rupture status significantly influences the EVT choice, likely based on the need for dual antiplatelet therapy. The discrepancy in initial adequate occlusion in the unruptured cohort is likely due to the higher use of flow diverters. Ruptured WNAs were more difficult to treat as evidenced by higher rates of retreatment and procedural complications, however this did not impact the final angiographic outcomes.

Disclosures T. Hardigan: 1; C; Neurosurgery Research and Education Foundation Fellowship. 2; C; Telos. B. Hendricks: 2; C; Medtronic. J. Yoon: None. C. Kellner: 1; C; Penumbra, Siemens. M. Lawton: 2; C; Zeiss, Aesculap. 6; C; Mizuho. J. Mocco: 1; C; Stryker, Microvention, Penumbra. 2; C; Cerebrotech, Viseon, Endostream, Vastrax, RIST, Synchron, Viz.ai, Perflow, CV Aid. 4; C; Cerebrotech, Imperative Care, Endostream, Viseon, BlinkTBI, Myra Medical, Serenity, Vastrax, NTI, RIST, Viz.ai, Synchron, Radical, Truvic. J. Mascitelli: None.