For an editorial in the International Journal of Stroke they are completely neglecting 100% recovery stroke rehab. They need to be destroyed and run by survivors.
Posterior circulation stroke from diagnosis to management, including recent data on thrombectomy for basilar artery occlusion from the BAOCHE and ATTENTION trials
Posterior circulation stroke accounts for one-fifth of all strokes, but despite this, it has been a neglected area. It can present considerable challenges in diagnosis, and there are fewer studies examining optimal treatment compared with anterior circulation stroke. This month’s issue of IJS attempts to address this balance. We have a particular focus on posterior circulation stroke with coverage of areas ranging from diagnosis, through acute treatment and thrombectomy, to secondary prevention. This initiative is particularly opportune with the recent announcement of two positive studies of thrombectomy for basilar artery occlusion (BAO).
Diagnosis of posterior circulation stroke can be challenging, in part because of substantial overlap in symptoms and signs with ischemia in the anterior circulation, but some clinical signs are highly specific to posterior circulation strokes because of the unique functions and vascular supply of the brainstem. A comprehensive review from Salerno and colleagues describes the clinical and corresponding anatomical features of PC stroke, and highlights specific syndromes.1 It also covers optimal imaging approaches. It makes for a very useful clinical update.
Management of posterior circulation stroke, particularly acute reperfusion therapy and neurointervention procedures for secondary prevention, has received much less attention than similar interventions for the anterior circulation. For example, whether thrombectomy is as effective for BAO as it is for anterior circulation stroke is debated, particularly after the negative BASICS trial.2 Our second review in this issue provides the latest data on management of posterior circulation stroke, both acute and secondary prevention.3 It highlights the results from two recent trials of thrombectomy presented in May at the European Stroke Congress 2022, which both showed that thrombectomy was highly effective for BAO.4 ATTENTION (EndovAscular TreaTmENT for acute basilar artery occlusION), the protocol paper of which is also published in this issue,5 recruited patients within 0–12 h from the estimated time of stroke onset in China. A total of 340 patients were randomly assigned to thrombectomy or best medical management in a 2:1 ratio. There was a highly significant improvement in the primary endpoint of modified Rankin score 0–3 at 90 days which was achieved in 104/226 (46%) of the endovascular therapy group and 26/114 (22.8%) of the best medical management group; an adjusted risk ratio of 2.1 (95% CI: 1.5–3.0). BAOCHE (Basilar Artery Occlusion CHinese Endovascular trial) differed in that it recruited patients within 6–24 h of symptom onset where the patient was ineligible for IV thrombolysis or had received IVT without recanalization.6 The planned sample size was 318, but after a planned interim analysis after 212 patients, the data and safety monitoring committee recommended early termination of the trial due to highly significant differences between the two treatments. In 217 patients available for the final analysis, 51 of 110 (46.4%) randomized to thrombectomy achieved mRS 0–3 at 90 days, compared with 26/107 (24.3%) receiving best medical therapy, giving an adjusted OR of improved outcome of 2.92 (95% CI: 1.56–5.47).2
The management review also summaries data on the effectiveness of decompressive surgery for posterior circulation intracerebral hemorrhage and ischemic stroke, and the latest data on stenting of symptomatic vertebral and basilar stenosis to prevent recurrent stroke. For the latter, it concludes that current data do not support intervening for intracranial vertebral or basilar stenosis, which has a high peri-procedural stroke risk, but that extracranial stenting may represent a treatment option although more trial data are required.2
BAOCHE demonstrated that some patients with BAO can benefit from thrombectomy up to 24 h after stroke.4 Collateral supply has been shown to be an important determinant of salvable tissue for the anterior circulation, and a paper from Broocks and colleagues, also in this issue, demonstrates the same applies for the posterior circulation.7 To address this question they assessed the posterior collateral circulation score (PCCS), a semiquantitative 10-point grading system was derived from computed tomography angiography (CTA) images. They studied 151 patients with acute BAO, of which 112 patients (74%) underwent endovascular treatment. In patients with a better PCCS (>5), the rate of good outcome was significantly higher (55% vs 11%; p = 0.001). They concluded that collateral supply modifies the effect of recanalization on functional outcome in BAO, particularly in patients with less pronounced ischemic changes on admission computed tomography.
Marked differences in the pattern of posterior circulation disease are seen across the globe. This is highlighted by an article in this issue from The Chinese IntraCranial AtheroSclerosis (CICAS) Study, a prospective, multicentre, hospital-based study which enrolled 228 patients from 22 Chinese centers with noncardiogenic posterior circulation stroke due to vertebral artery disease.8 They looked at the pattern of disease, risk factors, and associated prognosis. Intracranial vertebral disease was more common than extracranial disease in the Chinese population, while patients with combined intracranial disease were more likely to have hypertension. Compared with patients with single stenoses of the vertebral artery, those with multiple-segments-of-vertebral-artery involvement, or single segment involvement but also basilar involvement, had worse outcomes.
Although thrombectomy can transform outcome in stroke patients, not all patients benefit and there is great interest in identifying potentially reversible modifying factors. One such factor is renal impairment. A systematic review in this issue by Jeon and colleagues answers this question in cases from all vascular territories.9 They identified 11 studies including 3453 patients. Renal impairment was associated with fewer functional independence (odds ratio (OR), 0.49; 95% confidence interval (CI), 0.39–0.62) and higher mortality (OR, 2.55; 95% CI, 2.03–3.21) after thrombectomy. However, renal impairment was not associated with successful reperfusion or any increase in and symptomatic intracerebral hemorrhage. A further study on the same topic in this issue, from the DIRECT-MD group in 607 patients, also showed renal impairment was an indicator of poor outcome at 90 days in patients undergoing reperfusion therapy, both thrombolysis and thrombectomy.10
Finally, this issue also includes interesting data from the NAVIGATE ESUS MRI substudy. The main NAVIGATE ESUS study failed to show any benefit for treatment with rivaroxaban compared with aspirin in patients with ESUS (Embolic Stroke of Undetermined Source).11 This substudy acquired data on MRI at baseline and study termination in 718 participants. During the median 11-month interval between scans, incident covert brain infarcts were twice as common as clinical ischaemic stroke.12 However, assignment to rivaroxaban was not associated with reduction in the incidence of brain infarct (OR 0.77, 95% CI 0.49–1.2) or of covert brain infarct among those without clinical stroke (OR 0.85, 95% CI 0.50–1.4). New microbleeds were observed in 7% and did not differ among those assigned rivaroxaban versus aspirin (HR 0.95, 95% CI 0.52–1.7).
University of Cambridge
Email: hsm32@medschl.cam.ac.uk
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