Results from the BAOCHE randomised controlled trial (RCT), which found that the addition of thrombectomy to standard medical care within 6–24 hours in basilar artery occlusion stroke patients improved functional outcomes at 90 days—as compared to standard care alone—have now been published in the New England Journal of Medicine (NEJM).
These initial findings were presented earlier this year at the European Stroke Organisation Conference (ESOC 2022; 4–6 May, Lyon, France), and more recently at the LINNC Paris Course (30 May–1 June, Paris, France), by Tudor Jovin (Cooper University Health Care, Camden, USA).
At the outset of their NEJM report, Jovin and colleagues note that, although improved clinical outcomes have been observed with endovascular thrombectomy in anterior circulation stroke, the effects and risks of these procedures at 6–24 hours after symptom onset in patients with acute ischaemic stroke caused by basilar artery occlusion have not yet been extensively studied.
Therefore, in an open-label, multicentre RCT conducted in China over a five-year period, they set out to elucidate the effectiveness and safety of thrombectomy in this location by randomly assigning patients with basilar artery stroke who presented between six and 24 hours after symptom onset to receive either standard medical therapy plus thrombectomy, or a control group consisting of standard medical therapy only.
According to Jovin et al, the BAOCHE trial’s original primary outcome (90-day modified Rankin Scale [mRS] score of 0–4) was changed to a good functional status (mRS 0–3) at 90 days. Here, they clarify that this change was made to the primary outcome during the trial as new data from randomised trials became available that indicated an mRS score of 0–3 is “most indicative of treatment benefit”. The primary safety outcomes were symptomatic intracranial haemorrhage (ICH) at 24 hours and 90-day mortality.
A total of 217 patients were randomised 1:1 and included in the analysis, with 110 in the thrombectomy group and 107 in the control group. The researchers note that randomisation occurred at a median of 663 minutes after symptom onset, and intravenous thrombolysis was used in 14% of patients in the thrombectomy group and in 21% of those in the control group.
Jovin et al also detail that enrolment in BAOCHE was halted at a prespecified interim analysis timepoint because of the superiority demonstrated by thrombectomy at that stage. The researchers relay that the percentage of patients with a 90-day good functional status was almost twice as high in the thrombectomy group (46%) compared to the control group (24%), also noting an adjusted rate ratio of 1.81 here (95% confidence interval [CI], 1.26–2.60; p<0.001). In addition, the results for the original primary effectiveness outcome (mRS 0–4) were 55% in the thrombectomy group and 43% in the control group (adjusted rate ratio, 1.21; 95% CI, 0.95–1.54).
Regarding the prespecified safety outcomes, symptomatic ICH rates were higher in the thrombectomy group, occurring in six of 102 patients (6%) versus in one of 88 (1%) in the control group (risk ratio, 5.18; 95% CI, 0.64–42.18), while 90-day mortality was similar between the two groups at a rate of 31% in the thrombectomy group and 42% in the control group (adjusted risk ratio, 0.75; 95% CI, 0.54–1.04). The researchers further note that procedural complications occurred in 11% of the patients who underwent thrombectomy in BAOCHE.
These outcome data lead Jovin et al to conclude that, among patients with stroke due to basilar artery occlusion who presented 6–24 hours after symptom onset, endovascular thrombectomy led to a higher rate of good functional status at 90 days versus standard medical therapy alone. However, they also highlight the higher ICH incidence, and occurrence of procedural complications, associated with thrombectomy—and acknowledge that the generalisability of their findings outside of the Han Chinese population studied is somewhat limited.