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Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE)

This study has been completed.
Information provided by (Responsible Party):
Chelsea S. Kidwell, MD, Georgetown University Identifier:
First received: October 16, 2006
Last updated: February 26, 2014
Last verified: February 2014

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.

Condition Intervention Phase
Device: Merci Retriever and Penumbra System
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy

Further study details as provided by University of California, Los Angeles:

Primary Outcome Measures:
  • The Modified Rankin Scale Score [ Time Frame: at 90 days post-stroke ] [ Designated as safety issue: No ]

    Scale name is provided (Modified Rankin Scale) which is a standard measure of functional neurologic outcome in stroke. The scale runs from 0-6, running from perfect health without symptoms to death.

    • 0 - No symptoms.
    • 1 - No significant disability. Able to carry out all usual activities, despite some symptoms.
    • 2 - Slight disability. Able to look after own affairs without assistance, but unable to carry out all previous activities.
    • 3 - Moderate disability. Requires some help, but able to walk unassisted.
    • 4 - Moderately severe disability. Unable to attend to own bodily needs without assistance, and unable to walk unassisted.
    • 5 - Severe disability. Requires constant nursing care and attention, bedridden, incontinent.
    • 6 - Dead.

Secondary Outcome Measures:
  • Symptomatic Hemorrhagic Transformation [ Time Frame: from baseline to day 7 ] [ Designated as safety issue: Yes ]

    Symptomatic intracranial hemorrhage is defined as 4 point neurologic worsening on the National Institutes of Health Stroke Scale (NIHSS) score associated with parenchymal hematoma type 2 (PH-2*), remote intracerebral hemorrhage, subarachnoid hemorrhage, or intraventricular hemorrhage on imaging. The NIHSS is a scale measuring specific neurologic deficits caused by a stroke with scores ranging from 0 to 42, and higher scores indicating more severe neurologic deficits.

    *from the modified European Cooperative Acute Stroke Study (ECASS) II criteria

  • Day 90 Mortality [ Time Frame: at day 90 ] [ Designated as safety issue: No ]

Enrollment: 127
Study Start Date: May 2004
Study Completion Date: April 2012
Primary Completion Date: April 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: 1 Mechanical Embolectomy
Participants will be randomized to receive mechanical embolectomy treatment either with the Merci Retriever or Penumbra System and standard medical care or treatment with standard medical care alone.
Device: Merci Retriever and Penumbra System

The MERCI (Mechanical Embolus Removal in Cerebral Ischemia) Retriever consists of a flexible, nickel titanium (nitinol) wire with a helical-shaped distal tip. The helical distal tip is covered with a platinum radiopaque coil, which facilitates fluoroscopic visualization. The body of the MERCI Retriever is covered with a hydrophilic coating that helps facilitate device placement. The MERCI Retriever is available in 6 configurations (Merci Retrievers X6, L5, L4, L6, V series, DAC).

The Penumbra System uses a reperfusion catheter in parallel with a separator component and an aspiration source to achieve separation of the thrombus and subsequent aspiration of the occlusion from the vessel. The system is available in different sizes according to the target vessels (041 Reperfusion Catheter/Separator pair for use in vessels larger than 3mm, notably the ICA and M1; 032 Reperfusion Catheter/Separator pair for use in vessels 2mm - 3mm, notably the M2).

No Intervention: 2
standard medical care

Detailed Description:

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.


Ages Eligible for Study:   18 Years to 85 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00389467

  Hide Study Locations
United States, California
Kaiser Permanente Los Angeles Medical Center 4867 W Sunset Blvd., Los Angeles CA 90027
Los Angeles, California, United States, 90027
University of California at Los Angeles, UCLA Stroke Network, 924 Westwood Blvd #300
Los Angeles, California, United States, 90024
Cedars Sinai Medical Center 8700 Beverly Blvd., Los Angeles CA 90048
Los Angeles, California, United States, 90048
University of California at San Diego, UCSD Medical Center, 200 W. Arbor Drive, OPC, 3rd Floor Suite 3
San Diego, California, United States, 92103
Santa Monica-UCLA Medical Center, 1225 15th Street Santa Monica, CA 90404
Santa Monica, California, United States, 90404
United States, District of Columbia
Washington Hospital Center, 110 Irving Street, NW, Washington, DC 20010
Washington, District of Columbia, United States, 20010
Georgetown University, Georgetown University Hospital, Room GG012, Ground Floor Gorman, 3800 Reservoir Road, NW
Washington, District of Columbia, United States, 20007
United States, Florida
University of Miami 1400 NW 10th Street, 10th Floor, Miami FL 33136
Miami, Florida, United States, 33136
United States, Iowa
University of Iowa Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242
Iowa City, Iowa, United States, 52242
United States, Maryland
Suburban Hospital, 8600 Old Georgetown Road, Bethesda, MD 20814
Bethesda, Maryland, United States, 20814
United States, Massachusetts
Boston University, One Boston Medical Center Place, Department of Neurology, C329
Boston, Massachusetts, United States, 01228
Massachusetts General Hospital, 101 Huntington Ave Ste 300
Boston, Massachusetts, United States, 02199
United States, Missouri
St. Louis University Hospital, 3635 Vista Avenue at Grand Boulevard Saint Louis, MO
St. Louis, Missouri, United States, 63110
United States, New York
Columbia University, 710 W 168th St, NI 551, ,
New York, New York, United States, 10032
Cornell University, New York Presbyterian Hospital, Cornell Campus, 525 East 68th St, Box 141
New York, New York, United States, 10021
United States, Ohio
University of Cincinnati, Department of Neurology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Medical Sciences Bldg, Rm 4015, PO Box 670525
Cincinnati, Ohio, United States, 45267
United States, Pennsylvania
University of Pittsburgh, PUHC-426, 200 Lothrop Street
Pittsburgh, Pennsylvania, United States, 15213
United States, South Carolina
Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29403
Charleston, South Carolina, United States, 29403
United States, Tennessee
Chattanooga Center for Neurologic Research
Chattanooga, Tennessee, United States
United States, Texas
University of Texas at Houston, University of Texas, Houston Stroke Program, Department of Neurology, 6431 Fannin Street, MSB 7044
Houston, Texas, United States, 77030
United States, West Virginia
West Virginia University 1 Medical Center, Morgantown WV 26506
Morgantown, West Virginia, United States, 26506
Canada, Alberta
University of Calgary
Calgary, Alberta, Canada
Sponsors and Collaborators
University of California, Los Angeles
Principal Investigator: Chelsea S Kidwell, MD Professor of Neurology, Georgetown University
Principal Investigator: Reza Jahan, MD Associate Professor of Radiology, UCLA Medical Center, Interventional Neuroradiology
  More Information

No publications provided by University of California, Los Angeles

Additional publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Chelsea S. Kidwell, MD, Professor of Neurology, Georgetown University Identifier: NCT00389467     History of Changes
Obsolete Identifiers: NCT00094588
Other Study ID Numbers: P50NS44378
Study First Received: October 16, 2006
Results First Received: April 12, 2013
Last Updated: February 26, 2014
Health Authority: United States: Food and Drug Administration

Keywords provided by University of California, Los Angeles:
ischemic stroke
blood clot
Merci Retriever
Penumbra System
magnetic resonance imaging

Additional relevant MeSH terms:
Cerebral Infarction
Brain Diseases
Brain Infarction
Brain Ischemia
Cardiovascular Diseases
Central Nervous System Diseases
Cerebrovascular Disorders
Nervous System Diseases
Vascular Diseases processed this record on November 27, 2014