378 Impact of Thrombus Location on Total Recanalization in Endovascular Thrombectomy for Intracranial Anterior Circulation Occlusion

INTRODUCTION: Endovascular mechanical thrombectomy (MT) is the gold standard treatment for the treatment of large vessel occlusion (LVO) in acute ischemic stroke (AIS). Thrombolysis in cerebral infarction score (TICI) 3 recanalization is associated with better clinical outcome and may be impacted by anatomical thrombus location. METHODS: Patients were included if they were found to have an acute LVO of the ICA terminus or the MCA M1 segment. M1 occlusions were further categorized proximally to distally as proximal, midsegment, and distal. Subgroup analysis was carried out between bifurcation LVO (including distal M1 and terminus lesions) and proximal/middle segment M1 LVO. RESULTS: A total of 303 patients were treated with MT from 2016-2020, with 159 meeting inclusion criteria. Of these, 34 (21.4%) had LVO at the ICA terminus, 28 (17.6%) at the proximal M1 segment, 42 (26.4%) at the midsegment, and 55(34.6%) at the distal M1 segment. Proximal M1 LVO was significantly associated with TICI 3 as compared to terminus(79%vs.50%p=0.0215) and distal M1 lesions(79%vs.49%p=0.0103). Proximal and midsegment lesions showed significantly higher rates of recanalization than distal M1 and ICA terminus LVO(74.3%vs.49.4%,p=0.0015). Distal M1 and ICA terminus lesions were negative predictors on multivariate analysis (OR 0.78, 95%CI:0.67-0.91,p=0.0017) and good functional outcome (OR 0.83, 95%CI:0.73-0.95,p=0.0066). TICI 3 was achieved in 96(60.4%) cases, and TICI 2B in another 55(34.6%). TICI 2B was significantly associated with a higher proportion of mortality or hospice(25%vs11%p=0.0264) and lower good functional outcome(15%vs32%,p=0.0169) versus TICI 3. CONCLUSIONS: Proximal and midsegment M1 lesions were significantly associated with increased proportion of TICI 3 recanalization. TICI 3 recanalization was significantly associated with NIHSS reduction, good functional outcome and a home discharge disposition.