Abstract WP158: Impact Of Atrial Fibrillation On Clinical Outcomes After Endovascular Thrombectomy: A Post-Hoc Analysis Of The Defuse-3 Trial

Introduction: Previous studies have failed to show an interaction between known atrial fibrillation (AF) and treatment effect of endovascular thrombectomy (EVT) performed within 6 hours of time last known well. However, it is not known if these findings apply to patients treated beyond 6 hours. The objective of the present study is to determine if a known diagnosis of AF exhibits effect modification on the association between treatment (EVT vs. medical therapy) and outcomes in patients >6 hours from time last known well. Methods: We performed a post hoc analysis of the DEFUSE-3 trial investigating the functional outcomes in study participants stratified by AF status. Our primary endpoint was functional outcome as measured by the modified Rankin Scale (mRS) score. We constructed an ordinal logistic regression model to determine the association between EVT/medical therapy and mRS in subgroups by AF status. Secondary endpoints include functional independence (mRS 0-2 vs. 3-6), final infarct volume, sICH, and mortality, examined via binary logistic or linear regression. We fit treatment modality*AF interaction terms. Results: Among 182 participants, 62 had AF (34 randomized to EVT) and 120 did not have AF (58 randomized to EVT). Patients with AF were older (median: 76.5 vs 66.5), presented with a higher NIHSS (median: 17 vs 16), and received IV tPA less frequently (4.8% vs. 12.5%). In patients with AF, the odds of a one-point improvement in mRS in EVT vs. medical therapy were 4.56 (95% CI: 1.79-12.17), while in patients without AF, the odds were 2.42 (95% CI: 1.27-4.67). We found no significant interaction between AF and EVT for the primary or secondary endpoints. Conclusion: Our study did not show a significant interaction between AF status and EVT, with the caveat that the study may be underpowered to detect such an effect. The trend for greater treatment effect should be evaluated in larger studies.