SELECT2 1-Year
(2024)Objective
To evaluate long-term (1-year) clinical benefit of endovascular thrombectomy for patients with acute ischaemic stroke due to large vessel occlusion with large ischaemic core.
Study Summary
• Functional independence (mRS 0-2) at 1 year: 24% thrombectomy vs 6% medical care (RR 3.17)
• 1-year mortality numerically lower with thrombectomy (45% vs 52%, RR 0.89, NS)
Intervention
Endovascular thrombectomy plus best medical care versus best medical care alone
Inclusion Criteria
Age 18-85 years, pre-stroke mRS 0-1, acute ischemic stroke from ICA or M1 MCA occlusion, large ischemic core (ASPECTS 3-5 or core ≥50mL on CTP/MRI), within 24 hours of last known well
Study Design
Arms: Endovascular thrombectomy plus medical care vs Medical care alone
Patients per Arm: 178 thrombectomy vs 174 medical care (352 total)
Outcome
• Functional independence (mRS 0-2): 24% vs 6% (RR 3.17)
• Independent ambulation (mRS 0-3): 37% vs 18% (RR 1.85)
Bottom Line
In patients with large ischaemic stroke (ASPECTS 3-5 or core ≥50mL), thrombectomy plus medical care provided significant functional benefit at 1 year compared with medical care alone. Thrombectomy nearly quadrupled the rate of functional independence (24% vs 6%) with improved quality of life scores and non-significantly lower mortality.
Major Points
- Prespecified 1-year follow-up analysis of the SELECT2 trial (originally stopped early for efficacy at 90 days)
- First trial showing 1-year benefit of thrombectomy in large core stroke patients
- 1-year mRS distribution significantly favored thrombectomy (gOR 1.43, p=0.0019)
- Functional independence (mRS 0-2) at 1 year: 24% thrombectomy vs 6% medical care (RR 3.17)
- Independent ambulation (mRS 0-3): 37% vs 18% (RR 1.85)
- Number needed to treat for 1-point mRS improvement: 6 patients
- Mortality numerically lower with thrombectomy (45% vs 52%) but not statistically significant
- Quality of life (Neuro-QOL) scores higher in thrombectomy group across mobility, social health, and cognitive domains
- 24% of survivors showed ≥1-point mRS improvement between 90 days and 1 year
- Treatment effect consistent across subgroups including age, NIHSS, time window, ASPECTS, and core volume
- 93% follow-up rate at 1 year (329/352 patients)
Study Design
- Study Type
- Phase 3, open-label, international, multicentre, randomised controlled trial with blinded endpoint assessment (prespecified 1-year follow-up analysis)
- Randomization
- Yes
- Blinding
- Open-label with blinded outcome assessment. Trained assessors masked to treatment and imaging findings collected outcomes.
- Sample Size
- 352
- Follow-up
- 1 year
- Centers
- 31
- Countries
- USA, Canada, Spain, Switzerland, Australia, New Zealand
Primary Outcome
Definition: Ordinal modified Rankin Scale (mRS 0-6) at 1-year follow-up, with scores 5 and 6 merged for analysis
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| Median mRS 6 (IQR 4-6) | Median mRS 5 (IQR 3-6) | - (1.14-1.78) | 0.0019 |
Limitations & Criticisms
- 7% missing primary outcome data at 1-year (higher than REVASCAT but lower than MR CLEAN)
- Trial not powered to evaluate treatment effect differences across subgroups
- Neuro-QOL scores missing for considerable number of patients with missingness associated with treatment allocation
- Stroke recurrence data missing for ~50% of patients, primarily due to deaths
- Adverse event monitoring completed only up to 90-day follow-up
- Did not collect cause of mortality beyond 90 days
- Did not collect duration and type of rehabilitation received
- Only 20% of patients enrolled at non-US sites, limiting generalizability assessment
- Two protocol crossovers occurred (both at same site)
- Open-label design (though outcome assessment was blinded)
Citation
Sarraj A, Abraham MG, Hassan AE, et al. Endovascular thrombectomy plus medical care versus medical care alone for large ischaemic stroke: 1-year outcomes of the SELECT2 trial. Lancet. 2024;403(10428):731-740.