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 90 minutes from angiography 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
Primary Outcome — mRS Distribution at 90 Days
All randomized patients (anterior circulation LVO, IV alteplase within 4.5 hours)
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 angiography.
- 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 the functional independence gap was the largest of any 2015 trial that used a uniform device protocol (60% vs 35%, NNT of 4 from the secondary mRS 0-2 outcome).
See also