Interventional Radiology · Neurointervention · Primary publication with final follow-up

SAMMPRIS (2011): Intracranial Stenting versus Aggressive Medical Management

SAMMPRIS compared aggressive medical management alone with Wingspan intracranial stenting plus the same medical therapy in patients with recently symptomatic severe intracranial atherosclerotic stenosis.

Key takeaway

In patients with a recent TIA or non-disabling stroke caused by 70–99% intracranial atherosclerotic stenosis, aggressive medical management was superior to Wingspan stenting because stenting produced substantially more early strokes and deaths without a compensating long-term benefit.

At a glance

Study design: Investigator-initiated, multicentre, open-label, randomised superiority trial conducted at 50 centres in the United States, with blinded independent adjudication of clinical endpoints. Recruitment was stopped early following a safety review.
Population: Patients aged 30–80 years with a TIA or non-disabling stroke within the preceding 30 days, attributed to catheter-angiographically confirmed 70–99% atherosclerotic stenosis of a major intracranial artery.
Sample size: 451 participants: 224 assigned to PTAS plus aggressive medical management and 227 assigned to aggressive medical management alone
Intervention: Percutaneous transluminal angioplasty and stenting using the Gateway balloon and Wingspan self-expanding stent, together with aggressive medical management. Medical management included aspirin 325 mg daily, clopidogrel 75 mg daily for 90 days, intensive control of vascular risk factors with target systolic blood pressure below 140 mmHg or below 130 mmHg in diabetes and LDL cholesterol below 70 mg/dL, and a structured lifestyle-modification programme.
Comparator: Aggressive medical management alone using the same antiplatelet regimen, risk-factor targets and lifestyle-modification programme.
Primary endpoint: A composite of stroke or death within 30 days after enrolment, ischaemic stroke in the territory of the qualifying artery beyond 30 days, or stroke or death within 30 days after any subsequent revascularisation procedure for the qualifying lesion.

Key results

At 30 days, stroke or death occurred in 14.7% of the PTAS group versus 5.8% of the medical-management group (33 of 224 versus 13 of 227; P=0.002).
The estimated one-year primary-endpoint rates were 20.0% with PTAS versus 12.2% with medical management; the time-to-event curves differed significantly (P=0.009).
During a median final follow-up of 32.4 months, a primary-endpoint event occurred in 52 of 224 participants assigned to PTAS (23%) versus 34 of 227 assigned to medical management (15%; P=0.0252).
Beyond 30 days, primary-endpoint events occurred in 19 of 191 participants at risk in the PTAS group and 21 of 210 in the medical-management group, both approximately 10%, demonstrating no later benefit sufficient to offset the procedural hazard.
In the final analysis, any stroke occurred in 26% of the PTAS group versus 19% of the medical group (59 of 224 versus 42 of 227; P=0.0468), while major haemorrhage occurred in 13% versus 4% (29 of 224 versus 10 of 227; P=0.0009).

Limitations

Recruitment was stopped early because of excess periprocedural events in the PTAS group, reducing the achieved sample size and potentially limiting the precision of longer-term estimates.
Treatment allocation was not masked, although potential endpoints were assessed by independent adjudicators who were unaware of treatment assignment.
The results directly apply to recently symptomatic 70–99% atherosclerotic stenosis and the Gateway–Wingspan strategy; they should not be automatically extrapolated to asymptomatic disease, less severe stenosis, non-atherosclerotic arteriopathy or substantially different devices and selection protocols.
Aggressive medical management was a bundled intervention, so the trial cannot determine the independent contribution of dual antiplatelet therapy, risk-factor control or lifestyle modification.

Why it matters

SAMMPRIS overturned the expectation that intracranial stenting would improve outcomes in recently symptomatic severe intracranial atherosclerotic stenosis. It demonstrated that the early procedural hazard of Wingspan PTAS outweighed any potential later benefit and established intensive medical treatment as the preferred initial strategy in the studied population.

Practice implication

For patients resembling the SAMMPRIS population, aggressive medical management should be the initial treatment. Routine intracranial angioplasty and Wingspan stenting should not be used as a substitute for this regimen because the procedure increased early stroke or death and provided no compensating long-term advantage.

Exam pearl

Remember the decisive 30-day result: stroke or death was 14.7% with Wingspan PTAS versus 5.8% with aggressive medical management.

Viva questions

What was the clinical question addressed by SAMMPRIS?: It tested whether intracranial angioplasty and Wingspan stenting plus aggressive medical management was superior to aggressive medical management alone for preventing recurrent stroke in recently symptomatic severe intracranial atherosclerotic stenosis.
Which patients were enrolled in SAMMPRIS?: Patients aged 30–80 years with a TIA or non-disabling stroke within 30 days, attributable to catheter-angiographically confirmed 70–99% stenosis of a major intracranial artery.
What did aggressive medical management in SAMMPRIS include?: It included aspirin 325 mg daily, clopidogrel 75 mg daily for 90 days, intensive blood-pressure and LDL-cholesterol control, management of other vascular risk factors and structured lifestyle modification.
Which intracranial stent system was evaluated in SAMMPRIS?: The Wingspan self-expanding intracranial stent was deployed after angioplasty with the Gateway balloon.
What was the primary endpoint of SAMMPRIS?: It combined stroke or death within 30 days, later ischaemic stroke in the qualifying-artery territory, and stroke or death within 30 days of any subsequent revascularisation of that lesion.
What was the decisive 30-day SAMMPRIS result?: Stroke or death occurred in 14.7% with PTAS versus 5.8% with aggressive medical management, showing significant early harm from stenting.
Did longer follow-up reveal a delayed benefit from intracranial stenting?: No. Primary-endpoint events remained more frequent with PTAS at final follow-up, and similar post-30-day event rates did not compensate for the initial procedural hazard.
What is the principal management implication of SAMMPRIS?: Aggressive medical management is the preferred initial strategy for recently symptomatic 70–99% intracranial atherosclerotic stenosis; routine Wingspan PTAS should not replace it.
What is an important limitation when applying SAMMPRIS to current endovascular practice?: The trial evaluated a specific device and recently symptomatic population, so its procedural event rates should not be indiscriminately extrapolated to different devices, delayed treatment or more selectively chosen patients.