Christian Boehme, MD, PhD
Department of Neurology
Medical University of Innsbruck, Innsbruck, Austria
Twitter handle: @chris7ianb
The aim of the study was to assess the safety and efficacy of thrombectomy in basilar artery occlusion between 6 and 24 hours after onset. The authors found that thrombectomy in the late time window improved functional outcomes three months after the index event.
Tudor Jovin explains the difficulties in recruitment during the pandemic and equipoise issues after the interim analysis. The DSMB recommended to stop the trial because the pre-specified stopping boundary was crossed in favour of mechanical thrombectomy.
Alastair Webb asks why the investigators changed the primary functional outcome from mRS <5 to mRS<4 during the study. Tudor Jovin explains that randomised data at the time of the study planning were very scarce. After the BEST and BASICS trials, which used mRS 0-3 as the favourable outcome the investigators changed the mRS cut-off before any data were unblinded.
Alastair Webb implies that the BEST and BASICS trials showed less convincing benefits for the intervention than in BAOCHE, despite being done in the classic time window. Tudor Jovin replies that a main difference in the studies was the use of IVT in BASICS, and also the fact that in BAOCHE a larger part of the population had an NIHSS ≥ 10 points at admission. This subgroup had also a significant benefit in the BASICS trial. Regarding the use of IVT, Tudor Jovin thinks that the additional use of thrombolysis diluted the treatment effect of thrombectomy in the BASICS trial. With regards to BEST, the trial had to deal with a high rate of cross-overs which possibly led to the formally negative results. When looking strictly at patients treated per protocol or those as treated, the results are pretty similar between the BAOCHE and the BEST trial.
Alastair Webb asks if – now after having data from all three trials – is there sufficient evidence for thrombectomy in basilar artery occlusion for all time windows from 0-24h and not only for the late time window. Tudor Jovin thinks that for the 6-24h time window with the selection criteria in BAOCHE, thrombectomy is justified. He concludes that in patients with basilar artery occlusion with an NIHSS ≥ 10 – which was the largest part of participants in BAOCHE and along with the data from BASICS – patients should be treated with thrombectomy. Regarding other subgroups, further studies like TENSION are underway and also, a meta analysis would be very helpful to draw further conclusions.
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