Abstract Body: Introduction: AHA/ASA guidelines recommend endovascular clot retrieval treatment (EVT) for acute ischemic stroke (AIS) patients without pre-existing disability. However, 30% of AIS patients and 1/4^th of US population has a pre-existing disability. In a national survey, >50% of providers do not consistently offer EVT to pre-stroke disabled AIS patients. Pre-stroke disability is a nearly universal exclusion criteria for enrollment in acute stroke clinical trials. To reduce the research and clinical care disparities in stroke for those with pre-existing disability, high-quality data are urgently needed that delineate influence of pre-stroke disability profiles on response to medical and EVT management, socioeconomic aspects, and granular outcomes relevant to a baseline-disabled population.

Methods: TESTED is a prospective, observational, comparative effectiveness study that will enroll 1060 participants with large vessel occlusion AIS presenting within 24 hours of last known well and moderate-to-severe pre-stroke disability, defined as modified Rankin scale score (mRS) 3 and 4. We will compare the effectiveness of EVT to medical management and determine heterogeneity in treatment effect. Data collected to characterize pre-stroke functional status include: pre-stroke mRS, EQ-5D-5L, Academic Medical Center Linear Disability Scale, disease sources of disability (using Social Security Bluebook), caregiver burden, and profiles of functional impairments using the WHO International Classification of Functioning, Disability and Health (ICF). The primary outcome is 90-day level of disability and key secondary outcomes are utility-weighted mRS, return to pre-stroke mRS, EQ-5D-5L, and physical disability level on the Academic Medical Center Linear Disability Scale. Exploratory outcomes include: Montreal Cognitive Assessment, Home-time, caregiver burden, and others. Inverse probability weighting will be used to derive causal inference.

Results: Enrollment in TESTED will began in December 2023. Thus far, 98 of 1060 patients have been enrolled. 73% are women and average age is 81 (+/-12). Only 5.2% patients have been lost to follow-up. The study will complete enrollment in Spring 2028.

Conclusions: TESTED will provide rigorous data on the comparative effectiveness of EVT to medical management for LVO-AIS patients with pre-stroke disability. The data generated in the study will help reduce clinical care and research disparities among pre-stroke disabled patients.