CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-15). The draft was written by AI, the existence of all 4 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2630 · Search date 2026-08-15 · Methodology v0.7

Intracranial stenting,
does it really help with Reduced recurrent stroke in severe symptomatic intracranial stenosis?

30-Second Summary
D
Evidence Grade D · 34 · Safety warning
Both trials had more stroke events with stenting, but investigator overlap prevents the strongest repeated-refutation grade.
Both trials found significantly more 30-day stroke, death, or hard TIA with stenting, and SAMMPRIS also found more major hemorrhage. At one year in VISSIT, stroke or hard TIA was also unfavorable at 36.2% with stenting versus 15.1% with medical therapy. The American Academy of Neurology (AAN) guideline, reaffirmed in April 2025, states: ‘Stenting should not be recommended as the initial treatment for s-ICAS.’ It does not recommend PTAS for moderate 50%-69% stenosis or as initial treatment for severe 70%-99% stenosis. This guideline supplies clinical context and was not used to calculate the grade. Strict specialist-center assessment is required.
What the
research shows
The grade is D. In SAMMPRIS, 30-day stroke or death was 33/224 (14.7%) with stenting versus 13/227 (5.8%) with medical therapy. At about three years, events were 52/224 (23%) versus 34/227 (15%), an absolute difference of 9.0 points (95% CI 1.5-16.5). VISSIT also favored harm: its 30-day safety endpoint was 14/58 (24.1%) versus 5/53 (9.4%), and the one-year stroke or hard-TIA endpoint was 21/58 (36.2%) versus 8/53 (15.1%). Major investigators overlapped across trials, so they were not counted as independent repeated refutation; the result is D with 34 points.
What the
ads claim
Mechanically widening a stenosed artery does not guarantee fewer strokes. In this population, added periprocedural risk increased total clinical events.
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Useful facts when choosing a product

  • SAMMPRIS tested the self-expanding Wingspan system; VISSIT tested the balloon-expandable PHAROS Vitesse system.
  • The 2011 SAMMPRIS paper and 2014 long-term report describe the same 451-person trial.
  • VISSIT first author Zaidat and investigators including Barnwell also participated in SAMMPRIS.
  • Unlike verdict 1501 on aneurysm coiling, this verdict concerns recurrent-stroke prevention in atherosclerotic intracranial stenosis.
Gap Measurement · Verdict 2630 · D 34
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

SAMMPRIS randomized 451 patients with recent symptoms and 70%-99% stenosis to Wingspan stenting plus identical aggressive medical management, 224, or medical management, 227. The statistical coordinating center generated the sequence, potential events were adjudicated by masked independent panels, and primary analysis followed intention to treat. The NCT00576693 composite primary endpoint matched the paper. NINDS U01 NS058728 was the main support; Stryker supplied devices and some third-party monitoring. The 2014 report was longer follow-up of the same trial, not replication. VISSIT randomized 112, while the reported primary analysis used 58 and 53 treated patients. Micrus Endovascular initiated and funded VISSIT, and Codman stopped it after an unplanned analysis. The NCT00816166 one-year primary endpoint matched the publication.

02

Why this is classified as D (34)

Large hard-outcome trials found significant harm opposite to the benefit claim, but investigator overlap prevented classification as independent repeated refutation, giving D with 34 points.

Counterpoint. D does not mean the risk was small. It means the strong early harm signal lacks the investigator independence required for the strongest repeated-refutation grade.

Rejudgment record. Cross-check applied — SAMMPRIS and VISSIT reports, long-term follow-up, and both registrations were checked for event counts, intention-to-treat analysis, funding, early stopping, same-trial reporting, and author overlap

Scoring profile behind this grade
EndpointHHard endpoint - actual events such as death
ReplicationR1Single confirmatory trial
IndependenceI1Mixed funding sources
Effect sizeE-Harm increased in the trials
PrecisionC0The confidence interval leaves room for benefit

The scoring table and the verdict agree (D).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Reduced 30-day stroke or deathDBoth SAMMPRIS and VISSIT had more events with stenting.
Reduced recurrent events at one to three yearsDThree-year SAMMPRIS and one-year VISSIT outcomes both favored medical therapy.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Study 1Multicenter randomized aggressive-medical-therapy-controlled trial227Main support from NINDS U01 NS058728; Stryker provided devices and some third-party monitoringComposite of 30-day stroke or death and later stroke in the qualifying territoryThirty-day events were 33/224 (14.7%) versus 13/227 (5.8%); enrollment stopped early.Large pivotal hard-outcome trial
Study 2Long-term follow-up of the same SAMMPRIS trial4NINDS with in-kind device and monitoring support from industry partnersLong-term composite primary endpointEvents were 52/224 (23%) versus 34/227 (15%); three-year absolute difference 9.0 points (1.5-16.5).Continuation of the same trial, not separate replication
Study 3International multicenter randomized device trial versus medical therapy53Initiated and funded by Micrus Endovascular; Codman & Shurtleff managed and conducted the unplanned analysisThirty-day safety endpoint and one-year same-territory stroke or hard TIAThirty-day events were 14/58 (24.1%) versus 5/53 (9.4%); one-year events were 21/58 (36.2%) versus 8/53 (15.1%).Same harm direction but with major investigator overlap with SAMMPRIS
§

Receipt — 4 References

All 4 cited sources were verified for existence at the original page (as of 2026-08-15).

Chimowitz MI, Lynn MJ, Derdeyn CP, et al.; SAMMPRIS Trial Investigators. Stenting versus aggressive medical therapy for intracranial arterial stenosis. N Engl J Med. 2011;365(11):993-1003. PMID: 21899409. DOI: 10.1056/NEJMoa1105335.
checked
Derdeyn CP, Chimowitz MI, Lynn MJ, et al.; SAMMPRIS Trial Investigators. Aggressive medical treatment with or without stenting in high-risk patients with intracranial artery stenosis: the final results of a randomised trial. Lancet. 2014;383(9914):333-341. PMID: 24168957. PMCID: PMC3971471. DOI: 10.1016/S0140-6736(13)62038-3.
checked
Zaidat OO, Fitzsimmons BF, Woodward BK, et al.; VISSIT Trial Investigators. Effect of a balloon-expandable intracranial stent vs medical therapy on risk of stroke in patients with symptomatic intracranial stenosis: the VISSIT randomized clinical trial. JAMA. 2015;313(12):1240-1248. PMID: 25803346. DOI: 10.1001/jama.2015.1693.
checked
Turan TN, Zaidat OO, Gronseth GS, et al. Stroke Prevention in Symptomatic Large Artery Intracranial Atherosclerosis Practice Advisory: Report of the AAN Guideline Subcommittee. Neurology. 2022;98(12):486-498. Reaffirmed April 2025. PMID: 35314513. PMCID: PMC8967328. DOI: 10.1212/WNL.0000000000200030.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-15 · Corrections: none

Cite this verdict

Intracranial stenting x fewer recurrent strokes in severe symptomatic stenosis Evidence Grade D card
[Chamgap] Intracranial stenting x fewer recurrent strokes in severe symptomatic stenosis — Evidence Grade D·34. 4 cited sources checked. Source: https://chamgap.com/en/verdicts/cognition/intracranial-stenting-severe-symptomatic-stenosis-recurrent-stroke/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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