Endovascular Therapy Proven Effective for Basilar Artery Occlusion

August 7th, 2025

For years, mechanical thrombectomy was used to treat acute ischemic stroke caused by large vessel occlusions (LVOs), but strong evidence supporting endovascular therapy (EVT) for anterior circulation strokes involving the internal carotid or middle cerebral arteries emerged only in 2015. In contrast, using EVTs to treat basilar artery occlusions (BAOs), a posterior circulation stroke, remained controversial because of limited data.

Early trials, BEST (China) and BASICS (Europe/U.S.), failed to show a clear benefit of EVT in BAO. BEST struggled with patient crossover and recruitment, while BASICS had an unexpectedly high rate of favorable outcomes in the medical group (38%), potentially masking any treatment benefit.

Two New Trials

However, two 2023 Chinese trials — ATTENTION and BAOCHE — confirmed the benefit of EVTs for BAOs. Both demonstrated that EVT nearly doubled favorable outcomes (modified Rankin Scale [mRS] 0-3) from ~23% to 46%. The ATTENTION trial, which enrolled healthier patients and had more treated within 12 hours, showed particularly robust results.

A follow-up analysis of ATTENTION confirmed the durability of EVT benefit at one year:

• Favorable outcomes (mRS 0-3): 45% at both 90 days and one year.

• Excellent outcomes (mRS 0-1): improved from 20% to 28%.

• Mortality: 45% with EVT vs. 64% with medical therapy.

These findings surpass observational data, such as the BASILAR registry, where one-year mortality was 54% with EVT and 84% without.

EVT Implications

The definition of “favorable outcome” differs between stroke types: Anterior circulation stroke trials often use mRS scores of 0-2, while posterior circulation (like BAO) allows mRS scores of 0-3 because of differences in resulting impairments. Still, achieving mRS scores of 0-1 in 28% of EVT-treated BAO patients is notable, suggesting not just survival, but functional independence.

BAO outcomes appear more binary than anterior strokes: Patients either do very well or die, with fewer moderate outcomes.

In conclusion, ATTENTION and BAOCHE establish EVT as the new standard of care for acute BAO, particularly when performed within 12 hours. The results reinforce the importance of timely stroke intervention and may lead to broader global adoption of EVT for posterior circulation strokes.

For more information on these trials and their implications of treating BAOs with EVT, click here.