Introduction Wide neck aneurysms (WNAs) have classically been defined as having a neck width greater than 4 mm (N>4) and/or dome-to-neck ratio less than 2 (DTNR<2). Although there is a surplus of literature on the various treatment options for WNAs, there is less focused on the natural history of both ruptured and unruptured WNAs.

Purpose To utilize a previously collected multicenter WNA registry/EVERRUN registry and compare baseline patient and aneurysm characteristics of ruptured vs. unruptured WNAs.

Methods Ruptured and unruptured, saccular, not previously treated WNAs (N>4, DTNR<2, or both) were included. Differences in WNA morphology and patient demographics were compared between ruptured (R) and unruptured (U) cohorts. 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 Rvs. 223 U). There was a female preponderance in both groups without significant difference (R: 80.5%, U: 75.8%). Ruptured WNA had significantly smaller neck size(R: 3.72±1.39 mm, U: 4.5±1.78mm) and dome width (R: 5.04±2.39mm, U: 6.29±3.37 mm)(p<0.05) with a trend towards reduced height (R: 5.04±2.16mm, U: 5.74±3.01mm)(p= 0.05). Ruptured aneurysms had higher rates of DTNR <2 alone (R: 60.9%, U: 42.2%) and unruptured aneurysms having higher rates of both DTNR <2 and N>4 (R: 34.5%, U: 50.7%, p<0.05). N>4 alone was also more prevalent in the unruptured cohort (R: 4.6%, U: 7.2%). ICA-Pcomm location was more common in the ruptured cohort (R: 21.1%, U: 9.4%), while ICA-Oph location was more common in the unruptured cohort (R:2.3%, U: 17.0%)(p<0.05). Acomm location was also higher in the ruptured cohort (R24.1%, U: 15.2%). Higher percentages of Asian (A), African American (AA), and Hispanic (H) patients were in the ruptured cohort compared to Caucasian (C) patients (A, R: 6.9%, U: 0.9%; AA, R: 12.6%, U: 7.2%; H, R: 35.5%, U: 29.6%; C, R: 42.5%, U: 60.1%)(p<0.05).

Conclusions The most novel finding in this subsequent analysis is that ruptured WNAs tend to be smaller with unfavorable DTNR whereas unruptured WNAs tend to be larger with a favorable DTNR. Higher rates of Pcomm/Acomm location in the ruptured WNA cohort are consistent with previous studies of all aneurysms and the significant racial disparity in ruptured vs. unruptured WNAs highlight the need for further characterization of both the biological and societal risks that may underlie these results.

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.