Background and Purpose Endovascular therapy (ET) of ischemic stroke with large vessel occlusion has been proved effective by clinical trials and reported with good outcomes in real clinical settings since 2015. We aim to determine national trends of clinical outcome in ET and compare the outcomes before and after mechanical thrombectomy.

Methods We obtained all data from the nationwide database of Health Insurance Review & Assessment Service from 2008 to 2017. The patients with ischemic stroke who received ET were identified using International classification of disease-codes and several codes regarding to ET. In evaluating prognosis of patients receiving ET, good outcome was defined as discharge to home and poor outcomes as cerebral hemorrhage, physical disabilities and death. We analyzed the time points of ET to determine the factors affecting the prognosis. The study period was divided into three periods: 1.when stent-retriever was not used (non-ET period), 2.when it was used for off-label and non-reimbursement (transitional period), and 3.when it was reimbursed (ET period).

Results A total of 15,589 patients who were received ET between January 2008 and December 2017 were analyzed. Of the total subjects, 5,512 patients (35.4%) received intravenous tPA. 3,028 were treated at non-ET period, 4,113 were treated at transitional period and 5,360 were treated at ET period. The rate of home discharge was 35.9%, 39.7% and 41.7% respectively, which was statistically significant (p<0.0001). 3-months mortality were 25.7%, 22.0%, 19.5% (p<0.0001), and 1-year mortality were 34.5%, 30.1% and 26.4% (p<0.0001). There was a decrease in the likelihood of death (hazard ratio 0.693, 95% CI 0.645–0.744) in ET period. The rate of disability was 33.6%, 26.5% and 23.4% (p<0.0001).

Conclusions The nationwide health insurance data showed clinical outcomes of patients with ischemic stroke after ET were significantly better in the ET period in Korea.

Disclosures K. Seo: None. S. Suh: None. K. Lee: None. M. Kang: None.