Characterizing Hemodynamic Compensation in Patients With Intracranial Stenosis

Completed

Conditions studied: Stroke, Intracranial Stenosis

In brief

The overall aim of this work is to assess the relationship between stroke risk and hemodynamic compensation strategies, as measured using a novel 3.0 Tesla MRI protocol, in patients with symptomatic intracranial (IC) steno-occlusive disease. Recent studies have shown high two-year ischemic stroke rates in symptomatic patients with IC arterial stenosis. Therapy for IC stenosis patients includes revascularization with angioplasty, IC stenting, or bypass, however identification of patients most likely to benefit from these more aggressive interventions, rather than medical management alone, has been problematic. Accurate measurements of hemodynamic compromise are likely required to better define stroke risk and guide treatment decisions. Specifically, in IC stenosis patients with compromised cerebral perfusion pressure (CPP), the extent of hemodynamic compromise reflects the autoregulatory capacity of vasculature to increase arterial cerebral blood volume (aCBV) and/or develop collaterals to supplement cerebral blood flow (CBF). The prevalence of CBF collateralization and aCBV autoregulation has been hypothesized to correlate uniquely with stroke risk, however the extent of this correlation has been debated. The critical barrier to stratifying stroke risk rests with a lack of (i) methodology for measuring multiple hemodynamic factors with high specificity and (ii) noninvasive approaches capable of monitoring longitudinal progression of impairment. The investigators have demonstrated the clinical utility of relatively new, noninvasive MRI approaches for assessing cerebrovascular reactivity (CVR), aCBV, and collateral CBF. The investigators hypothesize that stroke risk can be more completely evinced from collective measurements of these parameters. Therefore, the investigators propose to implement a novel, validated hemodynamic MRI protocol to assess tissue-level impairment and compensation strategies in patients with IC stenosis. Using a collective approach combining measurements of collateral CBF, aCBV and CVR in multiple brain regions, in conjunction with a statistical model incorporating the above variables as possible prognostic factors, the investigators will quantify the extent to which two-year stroke risk is associated with hemodynamic compensation mechanisms. The noninvasive and multi-faceted scope of this investigation is intended to expand the diagnostic stroke infrastructure and elucidate new hemodynamic prognostic indicators of stroke in this high-risk population.

Key facts

Study ID: NCT02506907
Run by: Vanderbilt University
People needed: 63
Starts: 2012-08-01
Expected to finish: 2017-11-01
Last updated by the study team: 2018-01-25

Who can join

Age: 18 and older, up to 85. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

Adult patients (age 18-85, inclusive)
Symptomatic (TIA or ischemic stroke) in the hemispheric carotid territory of vascular stenosis
Vascular imaging demonstrating large vessel IC stenosis>50% or occlusion of IC carotid or MCA
Sub-acute stroke patients who have received intravenous or intra-arterial treatments
Sub-acute stroke patients ineligible for conventional acute stroke intervention. Language comprehension intact, motor aphasia mild or absent, competent to give informed consent
Most recent qualifying TIA or stroke within 60 days prior to performance date of hemodynamic MRI

You may not qualify if…

ECA stenosis > 70% determined by MRA, CTA, or DSA.
Acute stroke patients presenting with anterior circulation stroke onset eligible for intervention with intra-arterial thrombolysis or mechanical thrombectomy
MRI contraindications (e.g. non-compatible implants, pregnancy, etc.)
Non-atherosclerotic cervical or intracranial stenosis
Heart disease likely to cause cerebral ischemia, including cardiomyopathy with ejection fraction<25%, prosthetic valve, infective endocarditis, sick sinus syndrome, myxoma, left atrial or ventricular thrombus
Existing condition likely to lead to death within 2 years

Where it is running

Vanderbilt University Medical Center — Nashville, Tennessee, United States

Full record on ClinicalTrials.gov

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