Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy

Stroke most commonly occurs when there is a blockage of blood flow to one of the arteries in
the brain. The blockage is often caused by a clot. There is currently only one FDA-approved
stroke treatment. However, only 2 percent of ischemic stroke patients receive this
treatment because it must be given within 4.5 hours of the stroke onset. There is an
overwhelming need for new treatments that extend the time window to treatment since most
individuals with stroke arrive at the hospital after the 4.5-hour time window.

Two of the most promising new devices are the Merci Retriever, a tiny corkscrew device, and
the Penumbra System, an aspiration device. Both are designed to remove clots from arteries
and thereby restore blood flow to the brain.

The primary purpose of this study is to compare the effectiveness of treatment with the
Merci Retriever or Penumbra System within 8 hours of symptom onset to standard medical
treatment, and to identify people who might benefit from the devices by the appearance of
the stroke on multimodal computerized tomography (CT) or magnetic resonance imaging (MRI).
Previous testing has determined that the use of the Merci Retriever is successful in opening
up blocked blood vessels in approximately ½ of the individuals in whom it is used, and the
Penumbra System is successful in opening up blocked blood vessels in approximately 80% of
the individuals in whom it is used.

A total of 120 participants from approximately 30 different medical centers will be enrolled
into this study. Participants will be randomized to either receive treatment by mechanical
embolectomy with the Merci Retriever or Penumbra System and standard medical care or
treatment with standard medical care alone. Standard care for stroke patients may include
intravenous fluid, careful regulation of blood pressure, blood-thinning medicine (such as
heparin or warfarin), anti-platelet medicine (such as aspirin or clopidogrel), and
rehabilitation therapies.

Participants undergoing the Merci Retriever or Penumbra System procedure will have a
cerebral arteriogram with pictures taken with dye prior to the procedure to determine the
location of the blockage, and following the procedure to determine if blood supply has been
restored. The total mechanical embolectomy procedure with either device will take
approximately 1 to 2 hours. Participants will have brief neurological exams several times
during this time to monitor changes in their neurological condition.

Participants will have follow-up visits, including neurological exams, at 30 days and at 90
days.

This study is part of the Specialized Program of Translational Research in Acute Stroke
(SPOTRIAS), which allows researchers to enhance and initiate translational research that
ultimately will benefit stroke patients by treating more patients in less than 2 hours, and
finding ways to treat additional patients later.