Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy
Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy
The purpose of this study is to compare the effectiveness of treating acute ischemic stroke
 with mechanical embolectomy using the Merci Retriever or the Penumbra System within 8 hours
 of symptom onset to standard medical treatment, and to identify people who might benefit from
 mechanical embolectomy by the appearance of stroke on multimodal computerized tomography (CT)
 or magnetic resonance (MR) imaging.
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.
Inclusion Criteria:

 -  New focal disabling neurologic deficit consistent with acute cerebral ischemia (NIHSS
 >/= 6)

 -  Age >/= 18 ≤ 85

 -  Clot retrieval procedure can be initiated within 8 hours from onset

 -  Large vessel proximal anterior circulation occlusion on MR or CT angiography (internal
 carotid, M1 or M2 MCA)

 -  Pretreatment MRI performed according to MR RESCUE protocol

 -  Signed informed consent obtained from the patient or patient's legally authorized
 representative

 -  Premorbid modified Rankin score of 0-2

 -  Allowed but not required: patients treated with IV tPA (tissue plasminogen activator)
 up to 4.5 hours from symptom onset with persistent target occlusion on post-treatment
 MR RESCUE MR or CT protocol performed at the completion of drug infusion (Note:
 Rapidly improving neurological signs prior to randomization is an exclusion)

 Exclusion Criteria:

 -  NIHSS >/= 30

 -  Contraindication to MRI (pacemaker etc)

 -  Acute intracranial hemorrhage

 -  Coma

 -  Rapidly improving neurological signs prior to randomization

 -  Pre-existing medical, neurological or psychiatric disease that would confound the
 neurological, functional, or imaging evaluations

 -  Pregnancy

 -  Known allergy to iodine previously refractory to pretreatment medications

 -  Current participation in another experimental treatment protocol

 -  Contrast-Enhanced Neck MRA (magnetic resonance angiography) or CTA (computed
 tomography angiography) suggests proximal ICA occlusion, proximal carotid stenosis >
 67%, or dissection

 -  INR > 3.0 (international normalized ratio)

 -  PTT > 3 x Normal (partial thromboplastin time)

 -  Imaging data cannot be processed by the MR RESCUE computer

 -  Renal Failure (serum creatinine > 2.0 or Glomerular Filtration Rate [GFR] < 30)

 MRI Exclusion Criteria:

 -  Contraindication to MRI (pacemaker, etc)

 CT Exclusion Criteria:

 -  Contraindication to iodinated contrast**

 **Examples of possible iodinated contrast contraindications include:

 -  Hyperthyroidism

 -  History of severe allergic reaction to iodinated contrast material

 -  History of sever kidney disease as an adult, including tumor or transplant surgery, or
 family history of kidney failure

 -  Paraproteinemia syndromes or multiple myeloma

 -  Collagen vascular disease

 -  Severe cardiac insufficiency

 -  Severely compromised liver function

 -  Current therapy with metformin, aminoglycosides