MR RESCUE
A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke
Year of Publication: 2013
Authors: Chelsea S. Kidwell, Jeffrey L. Saver, Reza Jahan, et al.
Journal: New England Journal of Medicine
Citation: Kidwell CS, Saver JL, Jahan R, et al. A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke. N Engl J Med. 2013;368:914–923.
PDF: Clinical Question
Does neuroimaging-based selection identify patients with acute ischemic stroke who benefit from endovascular therapy?
Bottom Line
Endovascular therapy did not show a benefit over standard care in patients with large-vessel anterior circulation stroke, regardless of favorable penumbral imaging pattern.
Major Points
- MR RESCUE assessed whether imaging-defined penumbra could predict benefit from endovascular therapy.
- Randomized patients within 8 hours of symptom onset to mechanical thrombectomy vs standard care.
- Used MRI or CT to classify patients as having favorable penumbral vs non-penumbral pattern before randomization.
- No significant interaction between imaging pattern and treatment outcome.
- Trial failed to demonstrate benefit of endovascular therapy, possibly due to outdated devices.
- Laid groundwork for better patient selection methods in later trials (e.g., DEFUSE 3, DAWN).
Design
Study Type: Multicenter, randomized, controlled trial with imaging stratification
Randomization: 1
Blinding: Open-label with blinded outcome assessment
Enrollment Period: 2004 – 2011
Follow-up Duration: 90 days
Centers: 22
Countries: United States
Sample Size: 118
Analysis: Ordinal logistic regression (shift analysis); interaction analysis between imaging profile and treatment
Inclusion Criteria
- Acute ischemic stroke due to anterior circulation large vessel occlusion (ICA or MCA)
- NIHSS 6–29
- Randomization within 8 hours of symptom onset
- MRI or CT perfusion imaging prior to randomization
Exclusion Criteria
- Pre-stroke disability (mRS >1)
- Coma or rapid improvement
- Inability to undergo imaging or intervention
- Posterior circulation stroke
Baseline Characteristics
| Characteristic | Control | Active |
|---|---|---|
| Age (mean) | 65.6 | 65.4 |
| Female (%) | 41% | 39% |
| NIHSS (median) | 17 | 17 |
| Favorable penumbral pattern (%) | 58% | 58% |
| IV tPA received (%) | 54% | 55% |
Arms
| Field | Endovascular Therapy | Control |
|---|---|---|
| Intervention | Mechanical thrombectomy using Merci Retriever or Penumbra System | Supportive care and IV tPA if eligible; no endovascular therapy |
| Duration | Single procedure within 8 hours of onset; 90-day follow-up | 90-day follow-up |
Outcomes
| Outcome | Type | Control | Intervention | HR / OR / RR | P-value |
|---|---|---|---|---|---|
| 90-day modified Rankin Scale (mRS) distribution | Primary | Mean mRS 3.1 | Mean mRS 3.0 | 0.99 | |
| Recanalization rate | Secondary | NA | 67% | ||
| Mortality at 90 days | Secondary | 20% | 21% | 0.85 | |
| Symptomatic intracerebral hemorrhage | Secondary | 4% | 5% | ||
| Symptomatic ICH | Adverse | 5% in intervention vs 4% in control | |||
| Mortality | Adverse | Approximately 20–21% in both groups |
Subgroup Analysis
No difference in outcomes by imaging profile (favorable vs non-favorable)
Criticisms
- Small sample size and underpowered
- Outdated endovascular devices (Merci, Penumbra) with low reperfusion rates
- Long enrollment period (2004–2011) limited applicability to modern practice
- Imaging criteria for penumbra not standardized by today’s thresholds
Funding
National Institute of Neurological Disorders and Stroke (NINDS)
Based on: MR RESCUE (New England Journal of Medicine, 2013)
Authors: Chelsea S. Kidwell, Jeffrey L. Saver, Reza Jahan, et al.
Citation: Kidwell CS, Saver JL, Jahan R, et al. A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke. N Engl J Med. 2013;368:914–923.
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