Endovascular Thrombectomy Efficacy in Basilar Artery Occlusion: Impact of Collateral Circulation and Etiology on Functional Outcomes

BACKGROUND AND OBJECTIVES: Endovascular treatment (EVT) is widely regarded as superior to best medical treatment (BMT) for basilar artery occlusion. However, the benefit of EVT in patients with poor collateral circulation remains uncertain. METHODS: We conducted a post hoc analysis of data from the ATTENTION study. Patients were categorized into good and poor collateral groups based on CT angiography, using the Basilar Artery on Computed Tomography Angiography scores and the posterior circulation collateral score. The efficacy of EVT vs BMT was then assessed within each group. RESULTS: Among 238 patients, 116 had good collaterals and 122 had poor collaterals. In the good collaterals group, EVT significantly improved functional outcomes compared with BMT (modified Rankin Scale 0-3: 65.3% vs 34.1%; P = .004). By contrast, EVT offered limited benefit in the poor collaterals group (modified Rankin Scale 0-3: 27.5% vs 14.3%; P = .388). Subgroup analyses demonstrated that EVT consistently outperformed BMT across nearly all good collateral subgroups. A significant interaction between treatment modality and the presence of atherosclerosis was observed in the good collaterals group ( P = .038), with EVT showing greater benefit in patients with nonatherosclerotic stroke (odds ratio 7.33; 95% CI, 2.47-21.74). CONCLUSION: EVT is strongly recommended for basilar artery occlusion patients with good collateral circulation, especially those with nonatherosclerotic causes of stroke. For patients with poor collaterals, treatment decisions between EVT and BMT should be carefully individualized based on clinical context.