Conference Coverage

BASILAR: Endovascular treatment improves outcomes in BAO stroke


 

REPORTING FROM ISC 2020

LOS ANGELES – Endovascular therapy significantly improved functional outcomes and reduced mortality at 90 days, compared with standard thrombolysis alone, new evidence from a large, prospective registry study suggests.

Participants who received both interventions were almost five times more likely to be able to walk independently at 90 days compared with those who received thrombolysis alone.

Despite multiple trials supporting the potential benefits of endovascular therapy for anterior stroke, little prospective research addresses outcomes associated with an ischemic stroke caused by a posterior basilar artery occlusion (BAO).

“Basilar artery occlusion is the ‘orphan’ of the large vessel occlusions,” Raul Gomes Nogueira, MD, PhD, said here at a late-breaking abstract session at the International Stroke Conference sponsored by the American Heart Association.

“They account for about 5% of the large vessel occlusions – but have the most dismal prognosis.” Severe disability and mortality rates associated with BAO, for example, reach an estimated 68% to 78%, he said.

The results, from the EVT for Acute Basilar Artery Occlusion Study (BASILAR), were also simultaneously published in JAMA Neurology.

Prior studies in this patient population are generally single-center, retrospective studies and “the numbers tend to be small,” said Nogueira, who is affiliated with the Marcus Stroke and Neuroscience Center, Grady Memorial Hospital, Emory University School of Medicine in Atlanta, Georgia.

Nogueira and colleagues studied 829 consecutive adults who presented with an acute, symptomatic BAO. They examined a nationwide prospective registry study of people with radiologically confirmed BAO in 47 comprehensive stroke centers across 15 provinces in China.

The median age was 65 years and 74% were men. A total 182 participants received thrombolysis therapy within 6 hours of estimated BAO onset. The 647 people in the dual intervention group also received endovascular therapy within 24 hours.

Standard medical treatment included intravenous rt-PA or urokinase, antiplatelet drugs and systematic anticoagulation alone or in combination. Endovascular therapy included mechanical thrombectomy with stent retrievers and/or thromboaspiration, balloon angioplasty, stenting, intra-arterial thrombolysis, or a combination of these interventions.

Interestingly, participants were not randomly assigned, in part because of the favorable outcomes associated with endovascular therapy. “The high number of patients who received [the dual intervention] may suggest the existence of a lack of equipoise among participating centers,” the researchers note.

Key Efficacy Endpoints

A significantly higher proportion of people in the dual treatment group achieved the primary outcome, functional improvement at 90 days, at 32%, compared with 9.3% in the thrombolysis-only group. This endpoint was defined as a modified Rankin Scale (mRS) score of 3 or less, which reflects an ability to walk independently. The difference was statistically significant (P < .001).

The absolute difference between groups was 22.7% (95% confidence interval, 17.1%-28.2%) with an adjusted odds ratio of 4.70 (95% CI, 2.53-8.75; P < .001) in favor of dual intervention.

The number needed to treat for one additional patient to be able to walk unassisted was 4.4.

Other outcomes, including differences in National Institutes of Health Stroke Scale scores from baseline to 5 to 7 days or discharge, as well as propensity score matching and subgroup analyses, likewise supported the superiority of using both interventions.

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