ABSTRACT NUMBER: ESOC2026A1676 HEIGHTENED VULNERABILITY OF THE VERY-OLD TO HEALTHCARE SYSTEM DISRUPTIONS: TEMPORAL TRENDS IN STROKE CARE AND OUTCOMES

Abstract Background and aims As populations age, patients aged ≥80 years comprise a growing proportion of acute ischemic stroke (AIS) admissions. We evaluated whether decade-long advances in acute management and secondary prevention translated into sustained outcome improvements in this vulnerable population. Methods We analyzed 18,434 AIS patients aged ≥80 years (OAS) from the CRCS-K-NIH registry (2011–2022). Temporal trends in treatments and clinical outcomes were evaluated. Post-hoc analyses assessed whether post-2020 outcome deterioration represented a significant trend shift and examined whether similar inflection occurred in patients aged 18-79 years. Primary outcomes were 1-year mortality and 3-month utility-weighted modified Rankin scale (UW-mRS). Results OAS proportion increased from 17.4% to 27.3%. Initial stroke severity declined, atrial fibrillation prevalence decreased, and prestroke anticoagulation tripled (11.7% to 33.5%). Most treatments improved substantially: dual antiplatelet therapy nearly doubled and oral anticoagulation for atrial fibrillation increased. Intravenous thrombolysis showed nonlinear fluctuation with sharp decline around 2015. Endovascular thrombectomy increased until 2018 but subsequently plateaued. Despite treatment improvement, OAS outcomes showed significant inflection: 1-year mortality declined from 27.5% (2011) to 19.4% (2019), then reversed to 23.7% (2022); UW-mRS similarly deteriorated post-2019. In younger patients, functional outcomes continued improving post-2019, while mortality inflection was less pronounced (Figure). Conclusions Very-old AIS patients exhibited significant outcome inflection after 2019 despite treatment intensification, contrasting with younger patients, suggesting disproportionate vulnerability to systemic disruptions such as COVID-19 and healthcare strain. Conflict of interest H-J Bae reports grants from Astrazeneca, Bayer Korea, Bristol Myers Squibb Korea, Dong-A ST, Jeil Pharmaceutical Co., Korean Drug Co., Ltd., Ltd., Samjin Pharm, Takeda Pharmaceuticals Korea Co., Ltd., and Yuhan Corporation, and person fees from Amgen Korea, Bayer, Daiichi Sankyo, JW Pharmaceutical, Hanmi Pharmaceutical Co., Ltd., Otsuka Korea, SK chemicals, and Viatris Korea, outside the submitted work. Figure 1 - belongs to Conclusions