O-012 Trends of ruptured and unruptured aneurysms treatment in the US in post-ISAT era: a national inpatient sample analysis

Background The International Subarachnoid Aneurysm Trial has generated a paradigm shift towards endovascular procedures for treating intracranial aneurysms, but it remains unclear if this has led to a true reduction in the risk for aneurysmal subarachnoid hemorrhage (aSAH). Our study aims to simultaneously quantify the annual intervention rates for ruptured and unruptured cerebral aneurysms, in order to evaluate any association between the treatment burden of unruptured and ruptured aneurysms after the endovascular treatment era. Methods Admissions data from the National Inpatient Sample (NIS; 2004–2014) were extracted. Patients with a primary diagnosis of subarachnoid hemorrhage or unruptured aneurysms treated by either clipping or coiling were included. Within each year, this combined group was randomly matched to a non-aneurysmal control group, based on age, sex and Elixhauser comorbidity index. Multinomial logistic regression was performed to calculate the relative risk ratio (RRR) of undergoing treatment for either ruptured or unruptured aneurysms in comparison to the reference control group, adjusted for time. Results After adjusting for the NIS sampling effects, 243,7754 aneurysm patients were identified, 174,580 (71.6%) of whom were female. The mean (SD) age was 55.4±13.2 years. A total of 121,882 (50.01%) patients were treated for unruptured aneurysms, 79,627 (65.3%) endovascularly and 42,256 (34.7%) surgically. A total of 121,872 (49.99%) patients underwent procedures for aSAH, 68,921 (56.6%) endovascular and 52,951 (43.5%) surgical. Multinomial logistic regression revealed a significant year-to-year decrease in aSAH procedures compared to the control group of non-aneurysmal hospitalizations (RRR 0.963 per year, 95% CI 0.944–0.982, P Conclusion With each passing year, there is a significant decrease in RRR of undergoing treatment for aSAH, concomitant with a stable annual risk of undergoing treatment for UIA. Disclosures M. Salem: None. G. Maragkos: None. S. Gomez-Paz: None. L. Ascanio: None. L. Ngo: None. C. Ogilvy: None. A. Thomas: None. J. Moore: None.