Abstract 485: Outcomes of Mechanical Thrombectomy in Patients with Pre‐Stroke Disability: Subgroup Analysis from the EXCELLENT Registry

Introduction Patients with pre‐existing disability, defined by a baseline modified Rankin Scale (mRS) score of 2‐4, are often excluded or underrepresented in mechanical thrombectomy (MT) clinical trials for acute ischemic stroke due to large vessel occlusions (LVOs). As MT becomes more widely adopted in clinical practice, understanding its safety and effectiveness in this population is essential to guide individualized treatment decisions. Methods We conducted a prespecified subgroup analysis of the EXCELLENT registry (NCT03685578), a prospective, multicenter study evaluating MT using the Embotrap® stent retriever in patients with LVOs. Patients with anterior circulation LVO were stratified by baseline mRS 0‐1 versus 2‐4. The primary endpoint was absence of significant disability accumulation at 90 days, defined as return to baseline mRS or a ≤1‐point increase. Secondary outcomes included 90‐day functional independence (mRS 0‐2), favorable outcome (mRS 0‐3), all‐cause mortality, early neurologic deterioration (END, increase in NIHSS ≥4 within 24‐h after thrombectomy), and symptomatic intracranial hemorrhage at 24‐h (sICH). Multivariable logistic regression was used to identify independent predictors of these outcomes. Results Among 892 patients, 732 had baseline mRS 0‐1 and 160 had baseline mRS 2‐4. Patients with pre‐stroke disability were older (mean age 77.1 vs 68.2 years, p<0.001) and had more comorbidities, including atrial fibrillation, congestive heart failure (CHF), coronary artery disease, chronic obstructive pulmonary disease, and prior stroke or TIA. The primary endpoint of no significant disability accumulation was met by a similar proportion of patients regardless of baseline disability status (40.1% vs 33.6%, p=0.174). Independent predictors of this outcome included IV‐tPA administration (p=0.001), lower baseline NIH Stroke Scale (NIHSS) score (p<0.001), younger age (p=0.020), ≤3 thrombectomy passes (p=0.002), and absence of CHF (p=0.002). Patients with baseline mRS 0‐1 had significantly higher rates of 90‐day functional independence (49.0% vs 7.2%, p<0.001) and favorable outcome (66.1% vs 20.8%, p<0.001). After adjustment, baseline disability remained an independent predictor of lower odds of achieving both favorable outcome (p<0.001) and functional independence (p<0.001). Ninety‐day mortality was markedly higher in patients with baseline disability (43.8% vs 14.0%, p<0.001). Adjusted predictors of increased mortality included older age (p<0.001), higher NIHSS (p<0.001), >3 thrombectomy passes (p<0.001), CHF (p=0.002), and baseline disability (p<0.001), while IV‐tPA administration was protective (p=0.007). END occurred more frequently in patients with baseline disability (13.2% vs 7.6%, p=0.025), and after adjustment, was independently associated with >3 thrombectomy passes (p<0.001), but not with baseline disability (p=0.073). Rates of sICH within 24 hours were low and similar between groups (1.8% vs 1.9%, p=0.932). Conclusions Although patients with pre‐existing disability had worse rates of mortality, functional independence, and favorable outcome at 90 days, they were equally likely to avoid significant disability accumulation following MT compared to patients without baseline disability and experienced similar rates of sICH. These findings support the potential benefit of MT in selected patients with pre‐stroke disability and underscore the importance of individualized treatment decisions. Future large‐scale trials are warranted to further assess the efficacy of MT in this population.