PDF: MR RESCUE
(2013)Objective
To evaluate whether neuroimaging selection based on penumbral patterns identifies patients who benefit from endovascular therapy for acute ischemic stroke.
Study Summary
Intervention
Mechanical embolectomy using Merci Retriever or Penumbra system vs. standard medical care. Neuroimaging used to classify patients by penumbral pattern.
Inclusion Criteria
Ischemic stroke within 8 hours, anterior circulation occlusion, NIHSS 6–29, with MRI or CT-based penumbral imaging before randomization.
Study Design
Arms: Mechanical Embolectomy vs. Standard Care
Patients per Arm: Embolectomy: 64, Standard care: 54
Outcome
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- Trial failed to demonstrate benefit of endovascular therapy, possibly due to outdated devices.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).
Study Design
- Study Type
- Multicenter, randomized, controlled trial with imaging stratification
- Randomization
- Yes
- Blinding
- Open-label with blinded outcome assessment
- Sample Size
- 118
- Follow-up
- 90 days
- Centers
- 22
- Countries
- United States
Primary Outcome
Definition: 90-day modified Rankin Scale (mRS) distribution
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| Mean mRS 3.1 | Mean mRS 3.0 | - (-0.5 to 0.7) | 0.99 |
Limitations & 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- Outdated endovascular devices (Merci, Penumbra) with low reperfusion rates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
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.