A meta-analysis of recent basilar artery occlusion trials—including ATTENTION and BAOCHE—has further indicated the potential benefits held by endovascular therapy (EVT) in treating posterior-circulation large vessel occlusion (PC-LVO) stroke.
Writing in the Journal of NeuroInterventional Surgery (JNIS), authors Jeremy Heit (Stanford University, Stanford, USA), Gautam Adusumilli (Massachusetts General Hospital, Boston, USA) et al note that previous randomised controlled trials (RCTs) and meta-analyses were “underpowered” to demonstrate the superiority of EVT over medical therapy in the treatment of acute ischaemic stroke due to LVO of the posterior circulation.
“We performed an updated systematic review and meta-analysis after the publication of the BAOCHE and ATTENTION trials to determine whether EVT can benefit patients presenting with PC-LVO,” they add.
Results of the ATTENTION RCT were first presented at the 2022 European Stroke Organisation Conference (ESOC; 4–6 May, Lyon, France) by Raul Nogueira (University of Pittsburgh, Pittsburgh, USA), who stated, “[…] I think we can finally say we have conquered the basilar artery territory”, in his talk. The BAOCHE RCT’s findings were also presented at ESOC 2022 by Tudor Jovin (Cooper University Health Care, Camden, USA) and subsequently published in the New England Journal of Medicine (NEJM).
With these new and more positive data to hand, Heit, Adusumilli and colleagues sought to reassess the benefits of EVT following the negative—or, at the very least, inconclusive—findings from prior RCTs, such as the European BASICS trial and the Chinese BEST trial. Neither of these trials were able to demonstrate significantly improved outcomes with EVT as compared to standard medical therapy.
Using the research software solution Nested Knowledge, the authors screened literature for RCTs on EVT in PC-LVO stroke, they detail in JNIS. The primary outcome of their analysis was a 90-day modified Rankin Scale (mRS) score of 0–3, and secondary outcomes included a 90-day mRS score of 0–2, 90-day mortality, and rate of symptomatic intracranial haemorrhage (sICH). A random-effects model was also used to compute rate ratios (RRs) and their corresponding 95% confidence intervals (CIs).
Four RCTs featuring a total of 988 patients—556 in the EVT-plus-medical therapy arm and 432 in the medical therapy-only arm—were included in the meta-analysis.
Outlining their results, Heit, Adusumilli et al report that EVT resulted in “significantly higher rates” of mRS score 0–3 (RR=1.54; 95% CI 1.16–2.04; p=0.002) and functional independence (RR=1.83; 95% CI 1.08–3.08; p=0.024), and lower rates of mortality (RR=0.76; 95% CI 0.65–0.90; p=0.002) at the 90-day follow-up, compared with medical therapy alone.
However, patients treated using EVT also experienced higher rates of sICH (RR=7.48; 95% CI 2.27–24.61; p<0.001), the authors detail.
“EVT conferred significant patient benefit over [medical therapy] alone in the treatment of PC-LVO,” Heit, Adusumilli and colleagues conclude. “Future studies should better define patients for whom EVT is futile and determine factors that contribute to higher rates of sICH.”
Speaking to NeuroNews, Heit stated: “The higher rate of sICH may reflect the high rates of intracranial atherosclerotic disease in the Chinese population that comprised BEST, BAOCHE and ATTENTION. In BAOCHE and ATTENTION, there were high rates of EVT treatment with angioplasty and cerebral artery stent placement that often requires the administration of antiplatelet medications. Further study is needed to determine if these treatments result in increased rates of sICH.
“BAOCHE and ATTENTION also enrolled patients with a favourable posterior-circulation Alberta stroke programme early CT score (PC-ASPECTS)—which may have helped to enrich for patients likely to benefit from EVT. Additional research is needed to better define which patient populations respond favourably and unfavourably to EVT. Our ongoing NIH [National Institutes of Health]-funded PRECISE study is designed to help address this question, and we look forward to reporting our findings when the study is complete.”
“Our study is the largest collation of high-level evidence on the effectiveness of EVT compared to medical therapy in basilar stroke, and we were able to demonstrate a significantly greater benefit conferred by EVT in treating these patients,” Adusumilli added. “The number needed to treat was seven for good functional outcome (mRS 0–3) and functional independence (mRS 0–2), and 10 for preventing mortality. We were also able to reaffirm a strong reperfusion success rate (85%) of EVT in basilar stroke.
“However, this does not close the debate on EVT being beneficial in all patients presenting with basilar stroke—the key being ‘all’. Fifty-five percent of patients after EVT ended up with severe disability or died, so there is clear incongruence between reperfusion success and outcomes. As Dr Heit suggests, further work should focus on determining the patients who are not benefitted by EVT, and how we can treat them.”