Elena Zapata-Arriaza, MD

Markus HS, Harshfield EL, Compter A, Kuker W, Kappelle LJ, Clifton A, et al. Stenting for symptomatic vertebral artery stenosis: a preplanned pooled individual patient data analysis. Lancet Neurol. 2019;18:666-673.

Symptomatic vertebral artery stenosis is related to an increased risk of recurrent ischemic stroke. However, the superiority of endovascular treatment over the medical approach in vertebral stenosis is not supported by solid scientific evidence, so it’s difficult to determine which therapeutic option is better. Markus et al. aimed to define whether vertebral stenting is more effective than medical treatment for symptomatic vertebral stenosis, using individual patient data pooled from trials published up to now.

After reviewing randomized controlled trials comparing stenting vs medical treatment for vertebral stenosis, the authors included the VIST, VAST and SAMMPRIS trials in pooled analysis. Data from the intention-to-treat analysis were used for all studies. Primary outcome was any fatal or non-fatal stroke during follow-up. Secondary outcomes were posterior circulation stroke, any stroke or transient ischaemic attack, stroke or death, and periprocedural stroke or death, which was defined as stroke or death within 30 days of randomisation. Analyses were performed for vertebral stenosis at any location and separately for extracranial and intracranial stenoses.

Among all included trials, 168 participants (46 with intracranial stenosis and 122 with extracranial stenosis) were randomly assigned to medical treatment and 186 to stenting (64 with intracranial stenosis and 122 with extracranial stenosis). In thestenting group, the frequency of periprocedural stroke or death was higher for intracranial stenosis than for extracranial stenosis (16% vs 1% patients; p<0¡0001). There was no significant difference between either stenting or medical therapy alone in stroke prevention. There was no suggestion of any potential benefit for intracranial stenosis.

Despite study limitations (variety of medical therapy among trials, underpowered analysis due to premature termination of the VIST trial or patient selection based on non-invasive angiography imaging with patients assigned to stenting group without stenosis in VIST trial), this pooled analysis results makes it clear that intracranial stenosis stenting should be rejected as first option treatment because of the confirmed periprocedural risk. Until now, in the case of intracranial vertebral stenosis, the endovascular approach is considered in case of non-response to medical treatment. The risks to the patient must be carefully explained, although in these cases trying to choose the least bad or risky option is always difficult. In the case of extracranial stenosis, the risk of the procedure is acceptable, although the option of treating with medical treatment is also supported in the light of the absence of superiority of one therapeutic option over another. In any case, the anatomical issues, the experience of the center or the confirmation that the stenosis is really symptomatic (taking into account that sometimes the symptoms of the posterior territory can be vague) should influence the final decision.

As for the technical aspects, stenting in posterior circulation will most of the time associate greater risk. The impossibility or difficulty of placing a distal protection system or the need to use a balloon assisted stent that can occlude intracranial perforators  puts us at a disadvantage compared to the anterior circulation. It may be time to propose trials about other antiplatelet agents employment (other than ASA and clopidogrel) in intracranial vertebral stenosis, taking into account the results obtained.