Association Between Age and Endovascular Treatment Outcomes: Binational Registry of 9934 EVT Cases From Korea and Taiwan

BACKGROUND: As populations age, there is an increasing need to optimize endovascular treatment (EVT) and to understand country-specific differences in East Asia. We harmonized stroke registries from Korea and Taiwan to enable comparisons of patient characteristics and outcomes, with a particular focus on the impact of age. METHODS: Multicenter prospective stroke registries in Korea (CRCS-K [Clinical Research Collaboration for Stroke in Korea]) and Taiwan (TREAT-AIS [Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke]) were harmonized to form a unified data set of patients undergoing EVT. Outcomes included 3-month modified Rankin Scale, symptomatic intracranial hemorrhage, and successful recanalization. We assessed the association between age and outcomes in the overall population and those who were aged ≥80 years using logistic regression models, adjusting for relevant covariates. RESULTS: A total of 9934 EVT cases (7835 from Korea and 2099 from Taiwan) were included from 2011 to 2023. Patients had a mean age of 70.1±12.9 years (57.6% male; median National Institutes of Health Stroke Scale score, 14 [interquartile range, 9–19]). Compared with Korean patients, Taiwanese patients had a higher prevalence of risk factors and more severe strokes, contributing to lower rates of favorable 3-month outcomes. Increasing age was associated with poorer EVT results; among patients ≥80 years, 18% achieved a modified Rankin Scale score of 0 to 2, compared with 46% of younger patients. However, the risk of symptomatic intracranial hemorrhage did not significantly increase with age (adjusted odds ratio per year, 1.01 [0.99–1.02]; adjusted odds ratio of ≥80 years, 0.98 [0.75–1.29]). Prestroke functional independence, baseline hemoglobin, and bridging thrombolysis were identified as significant modifiers of outcomes in the oldest patients. CONCLUSIONS: Taiwanese EVT patients had more risk factors and worse outcomes than Korean patients. Advanced age is associated with poorer functional recovery, yet selected older patients, particularly those who were functionally independent before the stroke or received bridging thrombolysis, demonstrated meaningful benefit. These results underscore the importance of individualized treatment strategies and careful patient selection, especially as populations continue to age.