Endovascular Treatment for Basilar Artery Occlusion Stroke with Low NIHSS: Outcomes Explored

Background The role of endovascular treatment (EVT) in basilar artery occlusion (BAO) stroke patients with low NIH Stroke Scale scores (NIHSS <10) remains unclear, and decision‐making guidance is limited. This study sought to assess whether EVT improves outcomes in BAO stroke patients with low NIHSS. Methods We conducted a retrospective cohort study using the 2016‐2022 Nationwide Readmissions Database. Adults with acute BAO stroke and NIHSS 1‐9 were identified and grouped by treatment strategy: EVT (thrombectomy, angioplasty, and/or stenting) vs. medical management (MM). Primary outcomes were functional independence at time of discharge and in‐hospital mortality. Propensity score matching (PSM) adjusted for demographics, comorbidities, symptoms, stroke etiology, and other factors. Subgroup and interaction analyses examined the effects of stroke etiology (embolic vs. non‐embolic) and NIHSS severity. Causal mediation analyses were conducted using established methods; confidence intervals and statistical significance were calculated using bootstrapping and 1,000 simulations. All p‐values less than 0.05 were deemed statistically significant. Results Among 9,461 patients (median age 68, 38.3% female), 1,807 (19.1%) received EVT. After PSM, 2,888 MM and 1,632 EVT patients remained. Rates of functional independence were similar (33.8% EVT vs. 34.0% MM, p=0.24), but EVT patients had higher in‐hospital mortality (16.0% vs. 7.1%, p<0.001). NIHSS and stroke etiology significantly influenced EVT outcomes (interaction p<0.05). For embolic strokes and NIHSS >5, EVT was associated with increased odds of functional independence (OR 1.88, 95% CI 1.10‐3.21, p=0.021) without increased mortality (OR 1.42, 95% CI 0.71‐2.86, p=0.32). For non‐embolic strokes, EVT did not improve discharge outcomes (OR 0.85, 95% CI 0.70‐1.03, p=0.17) and was linked to higher mortality (OR 3.84, 95% CI 2.49‐5.92, p<0.001). Mediation analyses found that, among patients with non‐embolic etiology, higher rates of respiratory complications associated with EVT patients accounted for 75.8% (95%CI 59.7% to 98.3%, p<0.001) of the observed association between EVT and higher odds of death. Conclusion EVT in undifferentiated low‐NIHSS BAO stroke patients was not associated with better short‐term outcomes and was linked to increased mortality. Subgroup findings suggest EVT may benefit select patients with embolic etiology and NIHSS >5, but it may be harmful in non‐embolic cases, possibly driven by higher risks of respiratory complications associated with EVT.