SWIFT PRIME Trial: Stent-Retriever EVT Plus IV tPA vs IV tPA Alone
In patients with anterior circulation LVO who had received IV alteplase within 4.5 hours, does adding Solitaire stent-retriever thrombectomy improve functional outcome at 90 days compared with alteplase alone?
Saver et al. (NEJM 2015) · doi:10.1056/NEJMoa1415061 · 196 patients
Population
Included
- Age 18 to 80 years
- Acute ischemic stroke with NIHSS 8 to 29
- Proximal anterior circulation occlusion (intracranial ICA or M1 MCA) on CTA or MRA
- IV alteplase initiated within 4.5 hours of symptom onset
- Groin puncture achievable within 6 hours of onset
- Pre-stroke functional independence (mRS 0 or 1)
- Imaging selection excluding large established infarct core (initially RAPID-based core less than 50 mL; later simplified to ASPECTS 6 or higher)
- Age 18 - 80
- Clinical signs consistent with acute ischemic stroke
- Prestroke Modified Rankin Score ≤ 1
- NIHSS ≥ 8 and < 30 at the time of randomization
- Initiation of IV t-PA within 4.5 hours of onset of stroke symptoms, with investigator verification of correct dosing
- Thrombolysis in Cerebral Infarction (TICI) 0-1 flow in the intracranial internal carotid artery, M1 segment of the MCA, or carotid terminus, confirmed by imaging
- Treatment feasible within 6 hours of symptom onset and within 90 minutes from CTA or MRA to groin puncture
- Willingness to complete protocol-required follow-up visits
- Signed informed consent obtained
- Subject is affiliated with a social security system (if required by individual country regulations)
- Subject meets national regulatory criteria for clinical trial participation
Excluded
- Large established infarct on baseline imaging
- Severe pre-stroke disability
- Standard contraindications to endovascular treatment
- Posterior circulation stroke
- Symptom onset to anticipated puncture beyond 6 hours
Clinical Exclusion Criteria
- Contraindication to IV t-PA per local guidelines
- Pregnancy, lactation, or positive pregnancy test
- Protected individual status under French law
- Rapid neurological improvement suggesting stroke resolution
- Serious radiographic contrast sensitivity
- Known sensitivity to Nickel, Titanium metals or their alloys
- Concurrent investigational study participation
- Hereditary or acquired hemorrhagic diathesis
- Renal Failure as defined by a serum creatinine > 2.0 mg/dl or GFR < 30; Warfarin with INR > 1.7
- Hemodialysis/peritoneal dialysis requirement or angiogram contraindication
- Life expectancy less than 90 days
- Clinical presentation suggests a subarachnoid hemorrhage
- Suspected aortic dissection
- Comorbid disease compromising neurological evaluation or survival
- Current or recent history of illicit drug(s) or abuses alcohol (regular/daily consumption of more than 4 alcoholic drinks per day)
- Known history of arterial tortuosity, pre-existing stent, and/or other arterial disease preventing device access
Imaging Exclusion Criteria
- CT or MRI evidence of hemorrhage
- CT or MRI evidence of mass effect or intracranial tumor (except small meningioma)
- CT or MRI evidence of cerebral vasculitis
- CT showing hypodensity or MRI showing hyperintensity involving greater than 1/3 of the MCA territory (or in other territories, >100 cc of tissue)
- Baseline non-contrast CT or DWI MRI evidence of a moderate/large core defined as extensive early ischemic changes of ASPECTS < 6
- Basilar or posterior cerebral artery occlusion
- CTA or MRA evidence of carotid dissection or complete cervical carotid occlusion requiring stenting
- Imaging evidence suggesting mechanical thrombectomy inappropriateness per investigator judgment
Source: ClinicalTrials.gov NCT01657461· Retrieved 2026-06-08
Secondary Outcome: mRS 0-2 at 90 Days
Protocol-defined primary was the ordinal mRS shift: common OR 2.63, 95% CI 1.57 to 4.40
mRS 0-2 at 90 Days
Study Arms
- Agent
- Solitaire FR (Flow Restoration) or Solitaire 2 stent retriever (Covidien); uniform device protocol
- Route
- Endovascular (mechanical thrombectomy)
- Frequency
- Single procedure following IV t-PA. Workflow targets: qualifying-imaging-to-groin-puncture within 70 min; groin puncture within 6 h of onset and within 90 min of the qualifying CTA or MRA.
- Duration
- One-time procedure
- Co-interventions
- IV t-PA (alteplase) initiated within 4.5 h of onset in ALL patients. Best medical care per local guidelines.
Device + technique from Saver NEJM 2015 p.2287: Solitaire FR/2 only; concomitant cervical ICA stenting NOT permitted (angioplasty allowed for access). Stent retriever deployed 89%; GA 37%; mTICI 2b/3 88%; median imaging-to-groin 57 min. Funded by Covidien. Source: NCT01657461.
- Agent
- IV alteplase (t-PA), standard medical therapy, no thrombectomy
- Route
- IV / Medical
- Co-interventions
- IV t-PA (alteplase) within 4.5 h of onset in ALL patients (shared with intervention arm); best medical care per local guidelines. No endovascular thrombectomy.
Control = continue IV t-PA alone (Saver NEJM 2015 p.2286). 1:1 randomization. Control-arm BP/glucose/antithrombotic targets + imaging-selection table (S1) appendix-deferred. Source: NCT01657461.
Trial Design
Type
- International multicenter randomized trial
- IV tPA alone vs IV tPA plus Solitaire thrombectomy
- Imaging-confirmed proximal anterior circulation occlusion
- Large ischemic cores excluded
Timeline
Stopped early for efficacy after 196 patients
N
196
Enrollment
International multicenter RCT enrolling 196 patients across 39 centers between December 2012 and November 2014 (Saver NEJM 2015). Stopped early for efficacy at 196 of a planned 833 patients.
ClinicalTrials.gov
NCT01657461Bedside Pearl
For an alteplase-eligible LVO patient inside 6 hours with a small infarct core, SWIFT PRIME supports proceeding to Solitaire thrombectomy without delay. The primary mRS shift was significant and functional independence rose from 35% to 60% (NNT of 4, derived from the secondary mRS 0-2 outcome). EXTEND-IA, in a perfusion-selected population, reported a larger absolute gap of 71% versus 40%.
See also