Annual Case Volume and One-Year Mortality for Endovascular Treatment in Acute Ischemic Stroke.

BACKGROUND: The association between endovascular treatment (EVT) case volume per hospital and clinical outcomes has been reported, but the exact volume threshold has not been determined. This study aimed to examine the case volume threshold in this context. METHODS: National audit data on the quality of acute stroke care in patients admitted via emergency department, within 7 days of onset, in hospitals that treated ≥ 10 stroke cases during the audit period were analyzed. Ischemic stroke cases treated with EVT during the last three audits (2013, 2014, and 2016) were selected for the analysis. Annual EVT case volume per hospital was estimated and analyzed as a continuous and a categorical variable (in quartiles). The primary outcome measure was 1-year mortality as a surrogate of 3-month functional outcome. As post-hoc sensitivity analysis, replication of the study results was examined using the 2018 audit data. RESULTS: We analyzed 1,746 ischemic stroke cases treated with EVT in 120 acute care hospitals. The median annual EVT case volume was 12.0 cases per hospital, and mortality rates at 1 month, 3 months, and 1 year were 12.7%, 16.6%, and 23.3%, respectively. Q3 and Q4 had 33% lower odds of 1-year mortality than Q1. Adjustments were made for predetermined confounders. Annual EVT case volume cut-off value for 1-year mortality was 15 cases per year (P < 0.02). The same cut-off value was replicated in the sensitivity analysis. CONCLUSION: Annual EVT case volume was associated with 1-year mortality. The volume threshold per hospital was 15 cases per year.

Short- and long-term mortality after intravenous thrombolysis for acute ischemic stroke: A propensity score-matched cohort with 5-year follow-up.

ABSTRACT: It remains unknown whether intravenous thrombolysis (IVT), thrombectomy, or poststroke antithrombotic medication lower short- and long-term mortality in acute ischemic stroke (AIS). This study aimed to investigate the efficacy of IVT in AIS using propensity score matching, to determine whether IVT could reduce short- and long-term mortality, and to identify risk factors influencing short- and long-term mortality in AIS.During 2013 to 2014, the nationwide Korea Acute Stroke Assessment registry enrolled 14,394 patients with first-ever recorded ischemic stroke. Propensity score matching was used to match IVT and control cases with a 1:1 ratio. The primary outcome was survival up to 3 months, 1 year, and 5 years, as assessed using Kaplan-Meier estimates and Cox proportional hazards.In total, 1317 patients treated with IVT were matched with 1317 patients not treated with IVT. Survival was higher in the IVT group (median, 3.53 years) than in the non-IVT group (median, 3.37 years, stratified log-rank test, P < .001). Compared with the non-IVT group, thrombolysis performed within 2 hours significantly reduced the risk of 3-month mortality by 37%, and thrombolysis performed between 2 and 4.5 hours significantly reduced the risk of 3-month mortality by 26%. Thrombectomy significantly reduced the risk of 3-month mortality by 28%. Compared with no poststroke medication, poststroke antiplatelet medication was associated with 51%, 55%, and 52% decreases in 3-month, 1-year, and 5-year mortality risk, respectively. Poststroke anticoagulant medication was associated with 51%, 54%, and 44% decreases in the risk of 3-month, 1-year, and 5-year mortality, respectively.IVT and mechanical thrombectomy showed improvement in short-term survival. To improve long-term outcomes, the use of poststroke antithrombotic medication is important in AIS.