Introduction/purpose Introduction of the stent retrievers in 2012 has revolutionized the constant evolution of stroke intervention. However, analysis regarding nationwide utilization of mechanical thrombectomy and associated outcomes after approval of the stent retrievers has yet to be performed. Using Nationwide Inpatient Sample (NIS) database, our study analyzed the clinical outcome and trend of national utilization of interventional treatment for acute ischemic stroke over three periods, from 2006 to 2007, from 2008 to 2011, and 2012.

Data for 2006 to 2012 were extracted from NIS database provided by the Agency for Healthcare Research and Quality (AHRQ). Patient selection was based on the International Classification of Diseases, 9^th revision, clinical modification (ICD-9-CM: 433 to 437.1, 39.74 and 99.10) and diagnosis related group (DRG: 543) codes. Patient outcome was evaluated by discharge status, in-hospital mortality, length of stay, and in-hospital complications. Outcomes were grouped by three time periods (Post-MERCI: 2006–07; Post-Penumbra: 2008–11 and Stent Retrievers: 2012). Statistical analysis was performed using Chi-square, ANOVA and multivariate logistic regression accordingly.

Results The average acute stroke admissions per year are: 723,327 during 2006–07 (Post-MERCI); 737,125 during 2008–11 (Post-Penumbra) and 738,490 (Stent Retrievers). Incremental trend was shown for the utility of intravenous tissue plasminogen activator (IV-tPA) administration (1.5%, 2.5% and 3.5% respectively), mechanical thrombectomy (0.2%, 0.5% and 0.7%) and combination of both (0.1%, 0.4% and 0.5%) for corresponding duration. The rate of mortality was significantly lower during 2012 ([IV-tPA: 6.7%; p = 0.007]; [Mechanical thrombectomy: 17.1%; p < 0.0001]; [Combination: 24.3%; p < 0.0001]) compared to 2008–11 (8.2%, 19.3% and 33.2% respectively) and 2006–07 (9.3%, 25% and 27.4% respectively). However, the risk of intracranial hemorrhage was significantly higher during 2012 ([IV-tPA: 8.2%; p < 0.0001]; [Mechanical thrombectomy: 22.7%; p < 0.0001]; [Combination: 37.8%; p < 0.0001]) compared to 2008–11 (6.9%, 17.9% and 26.6% respectively) and 2006–07 (5.5%, 9.4% and 20% respectively).

The age specific mortality following the stroke intervention was significantly decreased for ≥ 80 years (20%; p < 0.0001) and 65–79 years (14.9%; p < 0.0001) in 2012 compared to 2008–11 (25.8% and 20.5% respectively) and 2006–07 (26.3% and 30.2% respectively). In patients <65 years, the reduction of the age specific mortality risk from 2006–07 to 2008–11 (23.7% to 17.2%; p < 0.0001) was also observed from 2008–11 to 2012 (17.2% to 17.4%; p = 0.07), but did not reach statistical significance. Nevertheless, there is increase in the age-specific moderate-severe disability for ≥ 80 years (71.5%; p < 0.0001) and 65–79 years (68.4%; p < 0.0001) in 2012 compared to 2008–11 (65% and 63.4% respectively) and 2006–07 (64.5% and 55.6% respectively). In patients <65 years, the significant increase in the age specific moderate-severe disability risk from 2006–07 to 2008–11 (50.9% to 59.7%; p < 0.0001) was not observed from 2008–11 to 2012 (59.7% to 58.4%; p = 0.15).

Conclusion Introduction of stent retrievers for mechanical thrombectomy in acute stroke intervention has significantly decreased the overall mortality as well as age-specific mortality, especially in patients with 65–79 and ≥80 years-of-age. Our findings suggest that age alone should not be an exclusion criterion for mechanical thrombectomy in an appropriate clinical setting.

Disclosures S. Boddu: None. X. Sun: None. M. Crimmins: None. D. Kimball: None. J. Knopman: None. A. Patsalides: None. P. Gobin: None. N. Lin: None.