Background and purpose The purpose of this study was to analyze whether early treatment of ruptured aneurysms improves clinical outcomes independent of aneurysm rebleeding.

Methods A prospectively maintained database of ruptured intracranial aneurysms treated at our center from 1996 to 2014 was analyzed. Patients <18 years old were excluded.

Results We identified 1176 consecutive patients with ruptured aneurysms who underwent treatment. Seven hundred and seven patients had their aneurysms secured within 48 h of subarachnoid hemorrhage. Treatment was delayed in 469 patients due to delayed presentation or transfer from other centers. No significant difference was seen between the two groups with respect to Age, Sex, Smoking status and pre-rupture modified Rankin scale. Patients in the early treatment group were more likely to have poor World Federation of Neurological Surgeons clinical grade (mean WFNS 2 vs. 1 p < 0.001). Patients in the delayed treatment group had larger aneurysms (8.56 mm vs. 7.15 mm p < 0.001) and aneurysms more often located in the posterior circulation (p = 0.02). No difference in the incidence of rebleeding was seen between the two groups. Early treatment was associated with improved clinical outcomes at both three and twelve months (Odds Ratio 2.13 95% Confidence intervals 1.31–3.45).

Conclusions Securing ruptured aneurysms early improves mid and long-term clinical outcomes independent of aneurysm rebleeding. Further investigation is required to define the mechanism of the benefit.

Disclosures N. Manning: None. E. Meyers: None. J. Schmidt: None. J. Claassen: None. E. Connolly: None. S. Lavine: None. P. Meyers: None.