Assessment of Endovascular Treatment for Acute Basilar Artery Occlusion via a Nationwide Prospective Registry

Abstract

Importance: Several randomized clinical trials have recently established the safety and efficacy of endovascular treatment (EVT) of acute ischemic stroke in the anterior circulation. However, it remains uncertain whether patients with acute basilar artery occlusion (BAO) benefit from EVT.

Objective: To evaluate the association between EVT and clinical outcomes of patients with acute BAO.

Design, setting, and participants: This nonrandomized cohort study, the EVT for Acute Basilar Artery Occlusion Study (BASILAR) study, was a nationwide prospective registry of consecutive patients presenting with an acute, symptomatic, radiologically confirmed BAO to 47 comprehensive stroke centers across 15 provinces in China between January 2014 and May 2019. Patients with acute BAO within 24 hours of estimated occlusion time were divided into groups receiving standard medical treatment plus EVT or standard medical treatment alone.

Main outcomes and measures: The primary outcome was the improvement in modified Rankin Scale scores (range, 0 to 6 points, with higher scores indicating greater disability) at 90 days across the 2 groups assessed as a common odds ratio using ordinal logistic regression shift analysis, adjusted for prespecified prognostic factors. The secondary efficacy outcome was the rate of favorable functional outcomes defined as modified Rankin Scale scores of 3 or less (indicating an ability to walk unassisted) at 90 days. Safety outcomes included symptomatic intracerebral hemorrhage and 90-day mortality.

Results: A total of 1254 patients were assessed, and 829 patients (of whom 612 were men [73.8%]; median [interquartile] age, 65 [57-74] years) were recruited into the study. Of these, 647 were treated with standard medical treatment plus EVT and 182 with standard medical treatment alone. Ninety-day functional outcomes were substantially improved by EVT (adjusted common odds ratio, 3.08 [95% CI, 2.09-4.55]; P < .001). Moreover, EVT was associated with a significantly higher rate of 90-day modified Rankin Scale scores of 3 or less (adjusted odds ratio, 4.70 [95% CI, 2.53-8.75]; P < .001) and a lower rate of 90-day mortality (adjusted odds ratio, 2.93 [95% CI, 1.95-4.40]; P < .001) despite an increase in symptomatic intracerebral hemorrhage (45 of 636 patients [7.1%] vs 1 of 182 patients [0.5%]; P < .001).

Conclusions and relevance: Among patients with acute BAO, EVT administered within 24 hours of estimated occlusion time is associated with better functional outcomes and reduced mortality.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Nogueira reported working with Stryker Neurovascular as a DAWN trial principal investigator (with no compensation), a TREVO registry steering committee member (with no compensation) and a consultant (with compensation); Cerenovus/Neuravi as an ENDOLOW trial principal investigator (with no compensation), EXCELLENT registry principal investigator (with no compensation), and ARISE-2 trial steering committee member (with no compensation); Imperative Care as an Imperative Trial principal investigator (with compensation); Phenox as a PROST trial principal investigator (with compensation); Biogen as a CHARM trial steering committee member (with compensation); Cerenovus/Neuravi, Phenox, Anaconda, Genentech, Biogen, Prolong Pharmaceuticals, Brainomix as a physician advisory board member with compensation; and Viz-AI, Corindus Vascular Robotics, Vesalio, Ceretrieve, Astrocyte, and Cerebrotech as a physician advisory board member with stock options. No other disclosures were reported.

Figures

Figure 1.. Distribution of the Modified Rankin Scale Score at 90 Days in All Patients and the Propensity Score Matching Data Set

EVT indicates endovascular treatment.

Figure 2.. Subgroup Analyses

This forest plot shows that the difference in the primary clinical outcome (common odds ratio indicating the odds of improvement of 1 point on the modified Rankin Scale at 90 days, analyzed with the use of ordinal logistic regression) favored the endovascular treatment (EVT) group across all prespecified subgroups. The common odds ratio was calculated by using ordinal logistic regression taking the following variables into account: age, baseline National Institutes of Health Stroke Scale score (NIHSS), baseline posterior circulation–Alberta Stroke Program Early Computed Tomography Score (pc-ASPECTS), onset to imaging diagnosis time, sex, diabetes mellitus, ischemic stroke, intravenous thrombolysis, onset to outcome measurement time, and location of occlusion. The thresholds for baseline NIHSS and baseline pc-ASPECTS were chosen at the median, and the thresholds for age and time from stroke onset to imaging diagnosis were chosen at the 75th percentile. BA indicates basilar artery; IVT, intravenous thrombolysis; OTI, onset-to-imaging diagnosis time; VA–V4, the fourth segment of vertebral artery.