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In people having a stroke, a new surgical procedure done right away reduces disability

Badhiwala JH, Nassiri F, Alhazzani W, et al. Endovascular Thrombectomy for Acute Ischemic Stroke: A Meta-analysis. JAMA. 2015;314:1832-43.

Review question

In people with acute ischemic stroke affecting the front part of the brain, does a surgical procedure, “endovascular mechanical thrombectomy” (EMT) improve outcomes?


An ischemic stroke occurs when an artery to the brain is narrowed or blocked by a clot and blood is not able to reach part of the brain. More than 4 out of 5 strokes are ischemic. Symptoms of ischemic stroke include difficulty with language (understanding and speaking), vision problems, headache, difficulty walking, and paralysis or numbness.

Very fast treatment of a stroke is critical to success. Doctors can use medications given by mouth, into the bloodstream, or directly to the brain to break up a clot and restore blood flow. Intravenous tissue plasminogen activator (tPA) dissolves clots and improves recovery from strokes, but it can also cause bleeding in the brain. Endovascular mechanical thrombectomy (EMT) uses a small device inserted into the artery to break up or remove a clot.

How the review was done

The researchers did a systematic review based on studies available up to August 2015.

They found 8 randomized controlled trials with 2,423 people (average age 67 years; 53% were men).

Key features of the studies were:

  • EMT began up to 12 hours after the beginning of the stroke (4 hours on average); and
  • EMT was compared with, or added to, tPA.

What the researchers found

The quality of evidence was moderate to high.

Compared with tPA alone, EMT:

  • increased revascularization (blood flow through the artery) at 24 hours; and
  • increased functional independence (ability to take care of oneself) at 90 days.

Compared with tPA, EMT did not:

  • increase bleeding in the brain; or
  • affect death.


In people with acute ischemic stroke, endovascular mechanical thrombectomy improves functional independence but does not reduce risk of death compared with tPA. If someone is having a stroke, they need to get medical attention immediately—call 911.

Endovascular mechanical thrombectomy vs tPA in people with acute ischemic stroke


Number of trials (number of people)

Rate of events with mechanical thrombectomy

Rate of events with tPA

Absolute effect of endovascular thrombectomy

Revascularization (blood flow through the artery) at 24 hours

4 trials (874 people)



About 42 more people out of 100 had blood flow through the blocked artery

Functional independence at 90 days

8 trials (2,387 people)



About 13 more people out of 100 were able to take care of themselves without help

Death at 90 days

8 trials (2,418 people)



No effect*

Symptomatic intracranial hemorrhage (bleeding in the brain) at 90 days

8 trials (2,422 people)



No effect*

*Although the rates for the 2 groups look a little different, the differences were not statistically significant. This means that the differences could simply be due to chance rather than due to the different treatments.

Related Topics


Intracranial hemorrhage
Bleeding inside the skull.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.
The body's network of blood vessels. It includes the arteries, veins, and capillaries that carry blood to and from the heart.

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