Abstract TP16: Collateral Flow in Posterior Circulation Ischemic Stroke Predict Outcome in Basilar Artery Occlusion: Undergoing Mechanical Thrombectomy

Basilar artery thrombosis is typically associated with devastating outcomes. EVT has proven to be highly effective in the anterior circulation yet outcomes and ways of selecting patients for EVT for basilar artery occlusion remain unclear. Mainly limited by relatively small number of patients as well as different center-specific practices, we evaluated clinical and radiographic variables associated with EVT outcomes. Methods: A single-center retrospective cohort of acute ischemic stroke patients with any LVO between January 2014 and January 2018 were reviewed which underwent EVT. Patients with basilar artery occlusion were identified based on presenting CTA/MRA (n=35). We stratified patients into good outcomes (37.1 % vs 62.9 % p=0.133) and good collaterals vs poor collaterals while adjusting for clot length, posterior circulation collateral score, reperfusion status. Results: A total of (n=334) patients were identified to have an LVO. Out of these (n=35) had basilar artery occlusions. (n=30) had emergent EVT while (n=5) were initially treated with medical management and taken for EVT as a rescue therapy. After stratifying for good vs poor outcomes, multivariate analysis showed that poor collateral score is associated with poor outcome (mRS=3-6) (OR 0.98 p=0.60 CI 0.67-0.97). Clot length greater than 10 mm is associated with poor outcome at 90 days (HR 0.325 p=0.045 CI 0.56-0.833). Conclusion: Basilar artery occlusions carry a worse prognosis in cases with poor collateral scores, clot length >10mm and longer time to reperfusion from symptoms onset.