Abstract 285: Impact of Smoking on Outcomes After Mechanical Thrombectomy for Stroke: A Retrospective Cohort Study

Background The impact of smoking on outcomes following mechanical thrombectomy (MT) for acute ischemic stroke (AIS) remainscontroversial. Smoking is a well‐established vascular risk factor for stroke; however, some studies have reported a “smoker'sparadox," suggesting improved short‐term outcomes following mechanical thrombectomy (MT). We aimed to investigate whethersmoking status is associated with functional recovery, recanalization success, and mortality in patients undergoing MT at acomprehensive stroke center. Methods We conducted a retrospective cohort study of all acute ischemic stroke (AIS) patients who underwent MT at a comprehensive strokecenter (2012‐2024). Patients were stratified by smoking status. The primary outcome was favorable functional outcome (modifiedRankin Scale mRS 0‐2) at discharge and3 months. Secondary outcomes included successful recanalization (mTICI ≥2b), in‐hospital mortality, and post‐proceduralcomplications. Multivariable logistic regression was used to adjust for confounders, including age, sex, NIHSS, and comorbidities. Results A total of 1,254 patients were included (smokers: 265 21.1%, non‐smokers: 977 78.9%). Smokers were significantly younger(61.3 ± 11.7 vs. 73.5 ± 14.1 years, p<0.001) and more likely to be male (61.9% vs. 43.5%, p<0.001). Stroke severity (NIHSS atadmission) was similar between groups (16.16 ± 6.64 vs. 16.76 ± 7.22, p=0.113). Smokers demonstrated better functional outcomesat discharge and 3 months in unadjusted analysis (mRS at discharge: 3.32 ± 1.78 vs. 3.70 ± 1.63, p = 0.002; mRS at 3 months: 3.08± 2.13 vs. 3.55 ± 2.11, p = 0.002). However, in multivariable analysis adjusting for age, NIHSS, ASPECT score, and comorbidities,smoking status was not independently associated with favorable outcome at 3 months (adjusted OR: 1.21, 95% CI: 0.82‐1.78, p =0.342), or with successful recanalization (mTICI ≥2b) (aOR: 0.89, 95% CI: 0.50‐1.59, p = 0.693). Conversely, smoking wasindependently associated with increased 90‐day mortality (aOR: 1.57, 95% CI: 1.01‐2.45, p = 0.046). Age (aOR: 0.95, 95% CI:0.94‐0.96, p < 0.001), lower NIHSS (aOR: 0.91, 95% CI: 0.89‐0.93, p < 0.001), and higher ASPECT scores (aOR: 1.39, 95% CI:1.23‐1.56, p < 0.001) were the strongest predictors of favorable outcomes. Diabetes was significantly associated with worserecovery (aOR: 0.50, 95% CI: 0.27‐0.91, p = 0.024). Conclusion Although smokers initially appeared to have better functional outcomes, this association was confounded by their younger age andother clinical factors. After adjustment, smoking status was not independently associated with favorable outcome at discharge and 3months and was associated with increased 90 day mortality risk. These findings challenge the notion of a “smoker's paradox" andreinforce the dominant role of age, stroke severity, and infarct burden in predicting functional outcomes after MT. Further researchis needed to explore the biological and behavioral mechanisms underlying these observations.