Economic and Efficient: Introducing the Bifurcation-Invisible Sign in Endovascular Thrombectomy for Middle Cerebral Artery Occlusions

Introduction: Selecting thrombectomy techniques for acute ischemic stroke due to large vessel occlusion significantly affects outcomes and costs. This study introduces the Bifurcation-Invisible (BI) sign identified on initial microcatheter angiogram in acute middle cerebral artery occlusions before endovascular thrombectomy. We aimed to evaluate whether this sign is associated with better angiographic outcomes using contact aspiration (CA) versus stent retriever (SR). Methods: In this study, we reviewed 285 cases of acute M1-segment middle cerebral artery (M1-MCA) occlusions treated with SR or CA. Angiographic success was evaluated using modified Thrombolysis In Cerebral Infarction (mTICI) scores after the first attempt, clinical outcomes by 90-day modified Rankin Scale (mRS) scores, and procedural costs were analyzed. Categorical variables were analyzed using χ2 or Fisher’s exact test, and continuous variables using Student’s t test or Mann-Whitney U test. Subgroup multivariate logistic analysis and interaction tests were conducted, with post hoc analysis applying Bonferroni correction. Results: BI-positive patients treated with CA had higher first-pass reperfusion rates (mTICI 2b-3: 64.0% vs. 41.3%, p = 0.005; Bonferroni-corrected p = 0.030) and 19.8% lower device costs (p < 0.05) than those treated with SR. BI-positive CA patients had higher first-pass reperfusion rates (mTICI 2b-3: 64.0% vs. 32.1%; p < 0.001; Bonferroni-corrected p = 0.002) and a 39.9% reduction in device costs (p < 0.05) than BI-negative patients. The interaction tests showed significant interactions between the presence of BI and CA for first-pass reperfusion rates (p = 0.007) and device costs (p < 0.001). Conclusion: The BI sign, a refined version of the branching-site occlusion sign identified via microcatheter angiography, could guide the selection of CA, improving recanalization rates and reducing costs in MCA occlusions.