Assessing cerebral blood flow response using a new index

Diagnostic Performance of the Resistance Index (RI) for the Assessment of Cerebral Vasoreactivity in Transcranial Doppler

This study is testing a new way to measure blood flow in the brain to see if it can help identify patients with narrowed or blocked carotid arteries who might need surgery.

Quick facts

• Study type: Observational
• Enrollment: 77 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Centre Hospitalier Universitaire de Nīmes (Academic / other)
• Locations: 1 site (Nîmes)
• Trial ID: NCT05780619 on ClinicalTrials.gov

What this trial studies

This observational study aims to evaluate the diagnostic performance of the Resistance Index (RI) in assessing cerebral vasoreactivity through transcranial Doppler ultrasound. The study seeks to identify patients with carotid stenosis or occlusion who may benefit from revascularization procedures by distinguishing those with normal vasoreactivity from those with altered responses. By simplifying the testing process, the goal is to reserve more complex assessments for patients who are likely to have abnormal vasoreactivity, thereby optimizing patient care and resource use.

Who should consider this trial

Good fit: Ideal candidates include patients with asymptomatic or symptomatic carotid stenosis of 70% or greater or occlusion of atheromatous origin.

Not a fit: Patients who are not eligible due to contraindications to Acetazolamide or those participating in other interventional studies may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could help identify high-risk patients who may still benefit from carotid revascularization, potentially reducing the risk of stroke.

How similar studies have performed: While the use of transcranial Doppler for assessing cerebral vasoreactivity is established, this specific approach using the Resistance Index is novel and has not been extensively tested.

Eligibility criteria

Inclusion Criteria:

* The patient must have given their free and informed consent and signed the consent form
* The patient must be a member or beneficiary of a health insurance plan
* Stenosis ≥ 70% in diameter reduction in NASCET equivalent or occlusion of atheromatous origin of the cervical internal carotid artery, asymptomatic or symptomatic.
* Presence of a temporal window sufficient to record the homolateral and contralateral middle cerebral artery.
* Patient of legal age with free and informed consent.
* Patient who has signed the consent form.
* Patient affiliated or beneficiary of a health insurance plan.

Exclusion Criteria:

* The subject is participating in an interventional study, or is in a period of exclusion determined by a previous study
* The subject refuses to sign the consent
* It is impossible to give the subject informed information
* The patient is under safeguard of justice or state guardianship
* Contraindication to Acetazolamide Diamox® injection.
* Absence of temporal acoustic window (non visualization of the cerebral parenchyma, no recordable intracranial vessel).
* Insufficient temporal window (visualizable brain parenchyma, no recordable MCA)
* Internal or common carotid artery stenosis ≥70% or occlusion, contralateral to the primary lesion.
* Stenosis ≥50% of the middle cerebral artery homolateral or contralateral to the cervical lesion.
* Patient in exclusion period determined by another study.
* Patient under court protection, guardianship, or conservatorship.
* Patient refusing to sign the consent form.
* Patient unable to express his or her will (dementia, disturbed consciousness, etc.)
* Patient for whom it is impossible to give informed information for health reasons or because of a language barrier.
* Pregnant, parturient, or breastfeeding patient.

Where this trial is running

Nîmes

• CHU de Nîmes — Nîmes, France (Recruiting)

Study contacts

• Principal investigator: Sarah Coudray — CHU de Nimes
• Study coordinator: Sarah Coudray

Conditions Stenosis; Occlusion; Acetazolamide