article290

MR RESCUE

"Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging Selection".
The New England Journal of Medicine. 2013. 368:914-923.
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Clinical Question

Does endovascular therapy improve outcomes in patients with acute ischemic stroke when selected based on perfusion-imaging and stratified by penumbral pattern?

Bottom Line

Penumbral imaging with CT or MRI did not identify patients who would benefit from endovascular therapy for acute ischemic stroke, and endovascular treatment with first-generation devices showed no superiority to standard care.

Major Points

Mechanical thrombectomy has been proposed to be beneficial for patients with acute ischemic stroke due to large-vessel occlusion in the anterior circulation, especially when administered within a narrow time window. However, whether advanced imaging could identify a subset of patients that benefit most from endovascular therapy remained uncertain.

Guidelines

As of publication, no updated guidelines have been reflected based on this study's findings. Moreover, newer-generation stent retrievers, not included in the study, may have different levels of clinical efficacy.

Design

- Multicenter, phase 2b, randomized, controlled, open-label, blinded outcome trial
- N=118 patients with large-vessel, anterior-circulation ischemic strokes
- Randomized to mechanical embolectomy (n=64) or standard care (n=54)
- Mean patient age: 65.5 years
- Mean time to enrollment: 5.5 hours

Population

Inclusion Criteria
- Age between 18 and 85 years
- NIHSS scores of 6 to 29
- Large-vessel, anterior-circulation ischemic stroke
- Randomized within 8 hours after symptom onset

Exclusion Criteria
- Any contraindication to endovascular therapy

Baseline Characteristics
- Mean age: 65.5 years
- 58% had a favorable penumbral pattern

Interventions

- Mechanical embolectomy (Merci Retriever or Penumbra System) or standard medical care
- All patients underwent pretreatment CT or MRI brain imaging

Outcomes

Primary Outcomes
- No significant interaction between pretreatment imaging pattern and treatment assignment based on 90-day modified Rankin scale scores
- Among all patients, no difference in mean scores on the modified Rankin scale between embolectomy and standard care

Secondary Outcomes
- Embolectomy was not superior to standard care even in patients with a favorable penumbral pattern
- 90-day mortality was 21%; symptomatic intracranial hemorrhage rate was 4%

Criticisms

- Limited by the use of first-generation mechanical thrombectomy devices, advances in clinical practices over the 8-year study period, and variable timing in treatment and imaging approaches.
- Study results may not apply to newer-generation thrombectomy devices with reportedly higher rates of revascularization and better clinical outcomes.

Funding

National Institute of Neurological Disorders and Stroke; study devices initially provided by Concentric Medical, and subsequently by study funds or third-party payers.