Stenting for Vertebral Artery Stenosis Shows No Clear Benefit Over Medication Alone

Vertebral artery stenosis (VAS) — narrowing of the arteries supplying the posterior brain — is a significant and underappreciated cause of ischemic stroke. Patients who have already experienced a transient ischemic attack (TIA) or non-disabling stroke attributable to VAS face substantial recurrence risk. While medical management (antiplatelet therapy, statins, blood pressure control, lifestyle modification) is standard, endovascular approaches including balloon angioplasty and stenting have been used in hopes of mechanically restoring blood flow and reducing recurrence. Whether this invasive strategy actually improves outcomes over optimized medical therapy alone has remained uncertain — the central question this Cochrane review set out to answer.

The review team searched MEDLINE, Embase, BIOSIS, Web of Science indexes, multiple Chinese databases, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform through December 9, 2025. Eligible studies were randomized controlled trials comparing endovascular therapy (ET) plus medical treatment (MT) versus MT alone in adults aged 18 or older with symptomatic VAS. Four multicenter RCTs met inclusion criteria: VAST, VIST, SAMMPRIS, and one additional trial, enrolling a combined 429 participants (231 in the ET+MT arm, 198 in the MT-alone arm) with a mean age of 63.4 years. Endovascular modalities included angioplasty alone, balloon-mounted stenting, and self-expanding stent placement.

For the primary short-term outcome — death or stroke within 30 days of randomization — the pooled risk ratio (RR) was 2.02 (95% CI 0.73 to 5.55; 4 studies, 429 participants), suggesting a numerically higher event rate in the ET+MT group but with wide confidence intervals that preclude a definitive conclusion. For longer-term fatal or non-fatal stroke in the territory of the treated vertebral artery (from 30 days post-randomization to end of follow-up), the RR was 0.54 (95% CI 0.29 to 1.01), hinting at possible benefit but again falling just short of statistical significance. Overall stroke (ischemic or hemorrhagic) during the entire follow-up yielded an RR of 0.76 (95% CI 0.46 to 1.26), and all-cause death an RR of 0.83 (95% CI 0.41 to 1.66). For stroke or TIA during follow-up, based on two studies with 234 participants, the RR was 0.65 (95% CI 0.39 to 1.06). None of these results reached conventional statistical significance.

Critically, no included study reported data on restenosis (≥50% re-narrowing of the treated artery) or good functional outcome — two clinically important endpoints that remain uncharacterized in this literature. Risk of bias assessment using Cochrane RoB 1 found high performance bias across all four trials, as blinding of participants and clinicians to treatment allocation was not feasible. Three of the four trials (VAST, VIST, SAMMPRIS) were stopped early, which typically inflates apparent treatment effects and reduces reliability. GRADE assessment rated all outcomes as low-certainty evidence.

The clinical implications are sobering but important. Despite widespread use of vertebral artery stenting in some centers, this review finds no high-quality evidence supporting its superiority over optimized medical therapy. The confidence intervals are wide enough to be compatible with either modest benefit or modest harm from endovascular intervention. Clinicians should exercise caution before recommending stenting outside of clinical trial settings, particularly given the procedural risks observed in the 30-day window. The authors call for larger, adequately powered RCTs that stratify by stenosis location (extracranial vs. intracranial), severity, and technique, with longer follow-up and standardized outcome reporting including restenosis and functional status.