Endovascular Therapy for Acute Vertebrobasilar Occlusion Stroke

Long B, Gottlieb M. Endovascular therapy for acute vertebrobasilar occlusion stroke. Acad Emerg Med. 2025;32(5):578-580.

Study Population: Four trials comprising 988 participants with posterior circulation stroke confirmed with neuroimaging

Favorable functional status (mRS 0–3), functional independence (mRS 0–2), and all-cause mortality within 90 days

Symptomatic intracranial hemorrhage

Endovascular therapy (EVT) has demonstrated benefit in the treatment of acute ischemic stroke associated with large-vessel occlusion (LVO).1^, 2 Basilar artery occlusion is rare, accounting for approximately 1% of ischemic strokes and 5%–10% of proximal intracranial occlusions. However, it is associated with significant disability and mortality without appropriate treatment.3^, 4 The American Heart Association guidelines state that EVT is a reasonable treatment option for those with vertebrobasilar artery occlusion (VBAO) based on observational studies.5 However, four randomized control trials (RCTs) have recently evaluated EVT in patients with VBAO.6^, 7^, 8^, 9 Here we summarize a systematic review and individual patient-level meta-analysis that assessed the safety and efficacy of EVT versus standard medial therapy in patients with VBAO.10

The systematic review and meta-analysis discussed here included four RCTs and 988 participants with basilar artery occlusion (referred to as VBAO in this meta-analysis) confirmed with neuroimaging who were randomized to EVT versus standard medical treatment alone.10 The systematic review excluded trials that enrolled patients with strokes other than VBAO, such as isolated vertebral artery occlusion. The included trials enrolled patients within 6 h (BASICS),6 8 h (BEST),7 12 h (ATTENTION),8 and 6–24 h (BAOCHE)9 from time of estimated VBAO onset. The BEST (131 participants), ATTENTION (340 participants), and BAOCHE (217 participants) trials were completed in China, while the BASICS trial (300 participants) was conducted in seven countries.6^, 7^, 8^, 9 The median age of the enrolled subject was 67 years (interquartile range 58–74 years). A total of 904 patients (91%) were randomly assigned within 12 h of estimated stroke onset, and large-artery atherosclerosis was the cause of VBAO in 459 patients (48%).

The primary outcome of the systematic review was favorable functional status, defined as a modified Rankin scale (mRS) score of 0–3 at 90 days. Secondary efficacy outcomes included functional independence (mRS 0–2) at 90 days. Safety outcomes included symptomatic intracerebral hemorrhage (sICH; based on the modified Safe Implementation of Thrombolysis in Stroke–Monitoring Study criteria)11 at 24–72 h and all-cause mortality within 90 days.10

Compared to standard medical treatment, EVT was associated with better chance of favorable functional status at 90 days (adjusted odds ratio [OR] 2.41, 95% confidence interval [CI] 1.78–3.26, absolute risk difference [ARD] 15.5%, number needed to treat [NNT] 7).10 EVT was associated with increased chance of functional independence at 90 days (adjusted OR 2.52, 95% CI 1.82–3.48, ARD 14.3%, NNT 7) and all-cause mortality (adjusted OR 0.60, 95% CI 0.45–0.80, ARD 9.8%, NNT 11). However, the risk of sICH was higher with EVT at 24–72 h (adjusted OR 11.98, 95% CI 2.82–50.81, ARD 5%, number needed to harm 20).10

There are several important limitations to this systematic review. First, there are issues with generalizability. All four trials were completed at high-volume centers with extensive experience in EVT, which has been shown to be associated with improved functional outcomes in patients with LVO.12 Three of the four trials were completed in China, with Chinese patients accounting for 690 of the total number of participants (70%).7^, 8^, 9 Studies have demonstrated that Asian populations have higher rates of intracranial atherosclerosis as compared to Western populations.13 However, subgroup analysis suggested EVT was beneficial in patients with and without intracranial atherosclerosis. Subgroup analysis also demonstrated benefit in those with and without atrial fibrillation.10 Second, there was significant heterogeneity among the four trials regarding inclusion criteria, age of the included patients, study duration, stroke severity thresholds, treatment windows, and interventional approaches. A third consideration is that this systematic review found that the risk of sICH was elevated with EVT compared to medical treatment alone in patients with VBAO.10 This is in contrast to several other meta-analyses which found similar rates of sICH with EVT versus medical treatment alone for LVO affecting the anterior circulation.1^, 2^, 14 However, all-cause mortality rates within 90 days were improved with EVT compared to standard medical therapy alone in patients with VBAO. Fourth, stroke severity differed in the included studies. The BASICS and BEST trials excluded patients with cerebellar mass effect, acute hydrocephalus, and extensive bilateral brainstem infarction.6^, 7 The ATTENTION and BAOCHE trials only included patients with posterior circulation Acute.

Stroke Prognosis Early CT Score (pc-ASPECTS) ≥6 for those <80 years, though ATTENTION did include patients ≥80 years with pc-ASPECTS of ≥8 points.8^, 9 For reference, the pc-ASPECTS score ranges from 0 to 10, with a score of 10 correlating to no visible ischemia and scores less than 8 associated with worse outcomes.15 However, most of the included participants had favorable findings on neuroimaging, with median pc-ASPECTs of 9, and 13 participants (1%) had a pc-ASPECTS of 4–5. Fifth, the BEST and BAOCHE trials were stopped prematurely, which can potentially overestimate the treatment effect.7^, 9 Additionally, a number of patients crossed over from medical treatment alone to EVT (28 [7%] controls overall), which could potentially underestimate a treatment effect, though the authors of the systematic review utilized intention-to-treat analysis to address this. Finally, the authors did not discuss the quality or level of certainty of the evidence.

Based on the available data, EVT within 24 h for patients with VBAO is associated with improvement in mRS, functional disability, and survival but an increased risk of sICH. Thus, we have assigned a color recommendation of green (benefits > harms) for EVT compared to standard medical treatment. The efficacy and safety of EVT for patients with mild stroke, isolated vertebral artery occlusion, time from stroke onset to imaging ≥12 h, premorbid mRS ≥2, and neuroimaging with extensive infarcts is unclear with the current data, and thus further study in these patient populations is needed. Importantly, a dedicated protocol for LVO that incorporates EVT and medical therapy with specialist consultation is necessary to optimize patient outcomes.16

The original manuscript was published in Academic Emergency Medicine as part of the partnership between TheNNT.com and AEM.

May 27, 2025