Long-term Neurocognitive Sequelae of Subclinical Microembolization During Carotid Interventions

This study is currently recruiting participants. (see Contacts and Locations)
Verified April 2015 by Stanford University
University of Wisconsin, Madison
Washington University School of Medicine
Information provided by (Responsible Party):
Wei Zhou, Stanford University
ClinicalTrials.gov Identifier:
First received: October 29, 2012
Last updated: April 2, 2015
Last verified: April 2015
Microembolization is commonly associated with carotid artery stenting (CAS), but our understanding of subclinical microembolization is superficial. Through collaborative effects of multidisciplinary team-experts, novel approaches, and longitudinal evaluations, we hope to better understand the clinical significance and long-term cognitive effects of microemboli. This proposal may change our current clinical practice by providing a better outcome measure for carotid interventions and improving outcomes of CAS procedures through risk factor stratification. Our central hypothesis is that development of subclinical microemboli is associated with decline in cognitive function following CAS and that the risk of development of microemboli themselves is associated with patient- and procedure-related factors. We hope that this prospective study will help to clarify these important issues in the era of rapidly evolving percutaneous interventions.

Condition Intervention
Carotid Artery Stenosis
Behavioral: Neuropsychological testing

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective

Further study details as provided by Stanford University:

Primary Outcome Measures:
  • Incidence of microemboli in correlation with changes in neurocognitive assessment performance [ Time Frame: 1 year following CAS procedure ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Risk factor stratification for incidence of microemboli [ Time Frame: 1 year following CAS procedure ] [ Designated as safety issue: No ]

Estimated Enrollment: 200
Study Start Date: June 2011
Estimated Study Completion Date: June 2016
Estimated Primary Completion Date: June 2016 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
Neuroimaging Correlates
Carotid revascularization can significantly reduce the risk of stroke in patients with severe carotid stenosis; however, it has been associated with cognitive decline in 25% of the older adults who undergo the procedure. Neuroimaging techniques that characterize white matter integrity and regional hypoperfusion have the potential to provide sensitive brain structure indicators that may be associated with memory decline following revascularization procedures. In this proposal, we hope to determine the risk factors and cognitive effect of microembolization following carotid revascularization procedures.
Behavioral: Neuropsychological testing


Ages Eligible for Study:   40 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Patients undergoing carotid intervention

Inclusion Criteria:

  • Patient is male or female >40 yrs of age.
  • Patient has occlusive extracranial carotid stenosis (≥70%)
  • Patient is scheduled to undergo an endovascular intervention of a lesion in the extracranial carotid artery
  • Patient agrees to voluntarily participate and signs an informed consent.
  • Patient agrees to be available for follow-up and is able to participate in all study testing procedures.
  • Patient has sufficient visual and auditory acuity for cognitive testing.

Exclusion Criteria:

  • Patient is unable to safely and comfortably undergo magnetic resonance imaging procedures (e.g., claustrophobia, implanted medical devices that are MRI incompatible such as pacemaker, defibrillator, neural stimulator etc)
  • Patient has an untreated or unsuccessfully controlled psychiatric disease (schizophrenia, bipolar disorder).
  • Patient has prominent suicidal or homicidal ideation.
  • Patient has acute illness or unstable chronic illness (e.g. uncontrolled hypertension, hepatic encephalopathy, portal hypertension, ascites, and esophageal varices, pancreatitis).
  • Patient with a history of neurological (e.g., multiple sclerosis, seizure disorder, Parkinson's disease) or systemic illness affecting central nervous system function.
  • Patient has prior closed head injury with ≥24 hours of amnesia.
  • Patient is unable to understand or sign the informed consent.
  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 ClinicalTrials.gov identifier: NCT01718600

Contact: Wei Zhou, MD 650-493-5000 ext 67339 weizhou@stanford.edu

United States, California
Palo Alto Veterans Affairs Recruiting
Palo Alto, California, United States, 94304
Contact: Elizabeth Hitchner, MA    650-493-5000 ext 68632    Elizabeth.Hitchner@va.gov   
Principal Investigator: Wei Zhou, MD         
United States, Missouri
Washington University School of Medicine Recruiting
St Louis, Missouri, United States, 63110
Contact: Kristin Geile, RN, MSN, CCRC    314-286-1506    geilek@wudosis.wustl.edu   
United States, Wisconsin
University of Wisconsin, Madison Recruiting
Madison, Wisconsin, United States
Contact: Vivek Prabhakaran, MD, PhD       VPrabhakaran@uwhealth.org   
Principal Investigator: Vivek Prabhakaran, MD, PhD         
Sponsors and Collaborators
Stanford University
University of Wisconsin, Madison
Washington University School of Medicine
  More Information

Responsible Party: Wei Zhou, Professor of Surgery, Stanford University
ClinicalTrials.gov Identifier: NCT01718600     History of Changes
Other Study ID Numbers: R01NS070308 
Study First Received: October 29, 2012
Last Updated: April 2, 2015
Health Authority: United States: Federal Government

Keywords provided by Stanford University:
carotid artery stenting
neuropsychological testing

Additional relevant MeSH terms:
Carotid Stenosis
Arterial Occlusive Diseases
Brain Diseases
Cardiovascular Diseases
Carotid Artery Diseases
Central Nervous System Diseases
Cerebrovascular Disorders
Nervous System Diseases
Vascular Diseases

ClinicalTrials.gov processed this record on May 26, 2016