The National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, is looking for individuals to participate in clinical studies. Participating in clinical trials allows you to play an active role in research on the nature and causes of many disorders of the brain and nervous system, and to possibly help physician-scientists develop future treatments. The information below is designed to help you quickly learn about actively recruiting research studies for which you or someone you know may be eligible.


Approximately 700,000 strokes occur annually in the U.S. making it the third leading cause of death and the leading cause of permanent disability among adults. Over one third of strokes occur in the posterior circulation, the leading cause of which is vertebrobasilar occlusive disease secondary to atherosclerosis. Symptomatic vertebrobasilar disease (VBD) carries a high annual risk of stroke, averaging 10-15% per year despite medical therapy. This represents a potentially treatable high risk stroke etiology. Advances in endovascular angioplasty and stenting have created new treatment options, but these interventions carry significant risks, and the selection criteria for appropriate candidates remains uncertain. Determining predictors of stroke in this population is the first step toward identifying those high risk patients most suitable for consideration of intervention. Our preliminary studies suggest that the risk of stroke in VBD is strongly related to the extent to which intracranial blood flow is compromised. The objective is to conduct a longitudinal study of patients with symptomatic VBD. Our central hypothesis is that patients with symptomatic VBD who demonstrate limitation of blood flow on quantitative magnetic resonance angiography (QMRA) are at higher risk of stroke.The primary aim of this proposal is to test the hypothesis that among patients with VBD, those with distal blood flow compromise are at higher risk of subsequent posterior circulation stroke than those with normal flow. Secondary exploratory aims of the proposal are to determine:the correlation between large vessel flow measured by QMRA and tissue level perfusion measured by MR perfusion in the posterior circulation, and the predictive value of each; other predictive factors for stroke in this population; hemodynamic effects of varying degrees of vertebrobasilar stenosis; changes in hemodynamic status of patients on medical therapy over time; utility of QMRA as a non-invasive screening and monitoring tool in VBD. The study is a prospective multi-center observational cohort study of patients with symptomatic angiographically confirmed vertebrobasilar atherostenosis (≥ 50%), or occlusion). Upon enrollment, patients will undergo hemodynamic assessment with noninvasive MR imaging (including QMRA and MR perfusion), the results of which will be kept blinded from treating physicians and the patients. Patients will be prospectively designated as demonstrating compromised or normal distal cerebral flow based upon an existing validated algorithm of individual posterior circulation vessel flow measurements. Baseline demographic, clinical and laboratory data will be gathered. Subsequently, patients will have monthly clinical follow-up and be re-imaged with QMRA at 6 month intervals for a minimum of 12 months. The primary endpoint will be stroke incidence in the vertebrobasilar territory at one year. Survival analysis methods, with censoring of patients not achieving endpoint at the end of the study period, will be used for comparison of patients with compromised versus normal blood flow. The overall goal of the study is to define the population of patients with symptomatic VBD at highest risk of recurrent ischemic events. The information gained can significantly impact the selection criteria and likelihood for success of future clinical trials aimed at assessing the efficacy of endovascular or surgical interventions for the treatment of VBD. Moreover, the ability to define a low risk population in whom the risks of expensive invasive interventions would be unnecessary will have an equally important impact on the management of the disease both from a clinical and cost perspective. Data regarding the hemodynamic effects and changes over time of vertebrobasilar occlusive disease may also enhance our understanding of the basic pathophysiology and mechanisms of stroke in this morbid disease entity.

Eligibility Criteria:

Inclusion Criteria: - Stroke or TIA in the vertebrobasilar territory - Conventional or CT angiographic demonstration of ≥50% stenosis or occlusion of extracranial or intracranial vertebrobasilar artery - Symptoms within 60 days of enrollment - Age 18 and above - Able to provide informed consent Exclusion Criteria: Neurologic criteria: - Major disabling stroke prohibiting the ability to return for follow-up assessment - Any neurological disease which would confound follow-up assessment Medical criteria: - Any severe co-morbidity condition with less than 12 month life expectancy - Known cardiac disease associated with cardioembolic risk specifically atrial fibrillation, prosthetic valves, endocarditis, left atrial/ventricular thrombus, cardiomyopathy with EF

Study Design:

Study Location:

Multiple U.S. Locations

Study Website: