Abstract Body: Introduction: First pass effect (FPE) in endovascular thrombectomy (EVT) is associated with favorable treatment course and recovery, making it an important prognostic indicator for patients undergoing EVT. Atrial fibrillation (AF) related strokes have been shown to be associated with greater rates of FPE in acute large vessel occlusions; however, the association between AF and FPE in medium vessel occlusions (MeVO) is unknown. We aimed to assess the association between AF and achieving FPE in MeVO.
Methods: A prospectively-maintained retrospective registry of adult acute ischemic stroke patients was retrospectively reviewed (10/2019-10/2023). Patients undergoing EVT for a MeVO in a middle cerebral artery segment (M2/M3) were included. Multivariable logistic regressions with 2500 bootstrap iterations for modified FPE (mFPE, defined as modified Treatment in Cerebral Infarction [mTICI] 2B/2C/3) and FPE (mTICI 2C/3) was performed using the following covariables: age, sex, comorbid conditions, anticoagulation/antiplatelet use, premorbid modified Rankin score, admission National Institutes of Health Stroke Scale, Alberta Stroke Program Early Computed Tomography Score, occlusion location and laterality, thrombolytic administration, and EVT approach (either aspiration-only or combination aspiration with stent retriever). Receiver operator characteristics curve analysis was performed to derive area under the curve (AUC) to assess model performance.
Results: Of 67 patients included, median age was 70 years (IQR 63-82). Most occlusions were in the distal M2 segment (88.1%). Rate of mFPE was 58.2% (39/67); rate of FPE was 34.3% (23/67). In multivariable regressions, AF (adjusted OR 0.04, 95% CI 0.01-0.49, p=0.01) and lack of antiplatelet/anticoagulant use (adjusted OR 0.05, 95% CI 0.01-0.71, p=0.03) were independently associated with lower likelihood of mFPE. AF was the only covariable significantly associated with lower odds of FPE (adjusted OR 0.08, 95% CI 0.01-0.63, p=0.02). Models for mFPE and FPE had AUCs of 0.86 (95% CI 0.78-0.94) and 0.80 (0.75-0.85), respectively.
Conclusion: AF was associated with a significantly lower likelihood of FPE and mFPE in thrombectomy for MeVOs. This may suggest a need to prepare for additional passes and rescue intraprocedural strategies in EVT for MeVO patients with AF. Future studies are needed to further investigate this relationship.