To characterize the association of onset to puncture time (OPT) with clinical outcomes among patients with acute basilar artery occlusion receiving endovascular therapy (EVT) in clinical practice.

Using the EVT for Acute Basilar Artery Occlusion (BASILAR) study, we identified consecutive patients with acute basilar artery occlusion receiving EVT in 47 comprehensive stroke centers in China from January 2014 to May 2019. The primary outcome was favorable functional outcome (defined as modified Rankin Scale score [mRS] 0–3) at 90 days. Secondary outcomes included function independence (mRS 0–2), mortality, and symptomatic intracerebral hemorrhage. The associations of OPT with clinical outcomes were analyzed using multivariable logistic regression (OPT as a categorical variable) and restricted cubic spline regression (OPT as a continuous variable).

Among 639 eligible patients, the median age was 64 years, and median OPT was 328 minutes (interquartile range 220–490). Treatment within 4–8 hours and 8–12 hours was associated with lower rates of favorable outcome (adjusted odds ratio, 0.63 [95% confidence interval (CI), 0.40–0.98] and 0.47 [95% CI, 0.23–0.93], respectively) compared with treatment within 4 hours. Restricted cubic spline regression analysis showed that the OPT had L-shaped associations with favorable outcome (p_nonlinearity = 0.028) and functional independence (p_nonlinearity = 0.025), with significant benefit loss throughout the first 9 hours, but then appeared relatively flat. The odds of mortality increased relatively for OPT up to 9 hours, but then leveled off (p_nonlinearity = 0.042). The association between symptomatic intracerebral hemorrhage and OPT was not significant.

Among patients with acute basilar artery occlusion in routine practice, earlier treatment with EVT was associated with better outcomes throughout the first 9 hours after onset, but benefit may sustain unchanged afterwards.

This study provides Class II evidence that for patients with acute ischemic stroke due to basilar artery occlusion, earlier EVT is associated with better outcomes.