Carotid Plaque Imaging in Acute Stroke

Study Overview
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Brief Summary
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The purpose of this study is to determine the frequency, characteristics, and consequences of vulnerable carotid artery plaques ipsilateral to an acute ischemic stroke or TIA in the territory of the internal carotid artery.

Detailed Description
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Even with extensive diagnostic workup the underlying etiology remains unidentified in about 25% of patients with acute ischemic stroke (AIS) or transient ischemic attack (TIA). Non-invasive high-resolution magnetic resonance imaging (HR-MRI) of the carotid artery allows detecting vulnerable plaques (VP) and quantifying single plaque components. The hypotheses behind this study are that i) a substantial proportion of cases of AIS and TIA within the anterior circulation and no identified cause (cryptogenic AIS or TIA) are caused by VP in the carotid artery; ii) that these patients are at a high risk of developing a recurrent stroke, TIA, or clinically silent lesions detectable by brain MRI; and iii) that VP in the carotid artery are associated with specific infarct patterns as detected by diffusion-weighted MR imaging. Finally, the investigators will search for biomarkers associated with vulnerable carotid artery plaques. Motivating this study are the following considerations: i) data on the frequency and characteristics of VP in patients with cryptogenic AIS or TIA will provide valuable insights into stroke mechanisms; ii) depending on the results this study may have implications for diagnostic decision making and provide the basis for the planning of targeted interventional studies.

Official Title
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Carotid Plaque Imaging in Acute Stroke

Conditions
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Stroke, Ischemic Attack, Transient

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 49 years old Acute ischemic stroke or transient ischemic attack (TIA) Neurological symptoms compatible with a stroke or TIA in the anterior circulation (territory of the internal carotid artery) Onset of symptoms within the last 7 days 1 or more acute ischemic lesion(s) visible on MR diffusion-weighted imaging (DWI) in the territory of a single internal carotid artery Presence of carotid artery plaques in the ipsilateral or contralateral carotid artery as defined by ultrasound (criteria: plaque thickness at least 2mm; located within 1cm proximal or distal to the carotid bifurcation) Written informed consent Exclusion Criteria: Primary referral to an outside hospital (to avoid recruitment bias) DWI positive lesions outside the territory of a single internal carotid artery Carotid artery stenosis > 69% (North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria) ipsilateral to the stroke or TIA as defined by ultrasound (systolic peak flow velocity ≥ 300 cm/s) Standard contra-indications for MRI Documented allergy to MRI contrast media History of radiation to the neck area Renal clearance < 30 ml/minute Creatinine levels > 2 times the upper limit of the standard range of the respective laboratory within the last 30 days prior to MRI Surgical procedure within 24 hours preceding the MRI

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Acute Ischemic Stroke, TIA<br>Patients admitted to a specialized stroke service because of an acute ischemic stroke or a transient ischemic attack (TIA). | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency and characteristics of vulnerable plaques (VP) in the carotid artery ipsilateral to an acute ischemic stroke (AIS) or TIA in the territory of the carotid artery in patients with a cryptogenic stroke | For the primary outcome, definition of a VP will be based on non-invasive high-resolution magnetic resonance imaging (MRI). We will classify plaques according to the American Heart Association - Lesion Type (AHA-LT) classification (Cai et al. Circulation 2002; Saam et al.). Comparisons will include: a comparison of the frequency and characteristics of VP ipsilateral vs. contralateral to the AIS or TIA a comparison of the frequency and characteristics of ipsilateral VP in patients with cryptogenic stroke as compared to patients with cardioembolic stroke or small vessel stroke | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pattern of acute ischemic lesions on brain MRI associated with VP in the carotid artery | The pattern of acute ischemic lesions on brain MRI associated with VP in the carotid artery will be analyzed. | Baseline | 
| Recurrence rates of AIS or TIA in patients with VP in the carotid artery | The recurrence rates of acute ischemic strokes or transient ischemic attacks will be evaluated at follow-up after 12, 24 and 36 months. | 12, 24, 36 Months | 
| Rate of new ischemic lesions on FLAIR MRI at 12 month follow-up in patients with VP in the carotid artery | The rate of new ischemic lesions on FLAIR MRI will be evaluated at follow-up after 12 months. | 12 Months | 
| Association between VP in the carotid artery and atherosclerotic plaques in the aortic arch as determined by transoesophageal ultrasound | The association between VP in the carotid artery and atherosclerotic plaques in the aortic arch as determined by transoesophageal ultrasound will be evaluated in patients with transoesophageal ultrasound. | Baseline | 
| Biomarkers associated with vulnerable carotid artery plaques | Biomarkers probably associated with vulnerable carotid artery plaques will be analyzed. | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stroke, Ischemic Attack, Transient, Magnetic Resonance Imaging, Carotid Arteries, Carotid Artery Plaque, Atherosclerosis