Introduction:

Stroke etiology may affect the prognosis of acute basilar artery occlusion (BAO). This study aimed to estimate the efficacy and safety of endovascular treatment (EVT) in BAO strokes due to the underlying stroke etiologies of large artery atherosclerosis (LAA) and cardioembolism (CE).

Patients and methods:

Patients with LAA and CE subtypes from the registry EVT for Acute Basilar Artery Occlusion Study (BASILAR) were selected for this analysis. We estimated the EVT treatment effect relative to standard medical treatment (SMT) in these patients by using a propensity score approach with inverse probability of treatment weighted estimation. Outcomes included 90-day favorable functional outcomes (modified Rankin scale (mRS) 0–3), functional independence (mRS 0–2), all-cause mortality, and symptomatic intracranial hemorrhage (sICH).

Results:

A total of 744 patients were included in the final analysis. After weighting with inverse probability of treatment estimation, the patients who, based on their characteristics, were treated with EVT rather than SMT, demonstrated higher rates of favorable functional outcomes in both the LAA (29.2% vs 11.7%, adjusted OR with 95% CI: 4.34 [2.15–8.78], p < 0.001) and the CE subtype (36.0% vs 8.1%, adjusted OR with 95% CI: 9.14 [1.96–42.55], p = 0.005). A similar finding was also observed for functional independence. EVT patients also demonstrated lower rates of mortality than SMT. Among EVT patients, no significant difference was observed in mortality or sICH between LAA and CE groups, but LAA patients had lower rates of favorable functional outcome and functional independence (29.2% vs 37% and 24.2% vs 32.9%, respectively), where the latter remained significant after adjustment for imbalances in baseline data (p = 0.04).

Conclusions:

In acute BAO strokes, both LAA and CE patients who, based on their characteristics, were treated with EVT rather than SMT, demonstrated better outcomes. Among EVT patients, LAA and CE subtypes displayed important baseline and treatment differences, and LAA patients were less likely to achieve functional independence at 3 months, but mortality and sICH were similar between LAA or CE subtypes. These results need to be confirmed in future clinical trials.