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RecruitingNCT05780619REVACEIRUpdated Jul 8, 2026

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

An observational study in Stenosis and Occlusion, sponsored by Centre Hospitalier Universitaire de Nīmes. Recruiting at 1 site in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-08.

Sponsored by Centre Hospitalier Universitaire de Nīmes · Observational

From the registry’s dates

  • Started Jun 2023; still recruiting 3 years 5 months later.
Study type
Observational
Model
Cohort
Time perspective
Prospective
Enrollment
77
Ages
18 Years and older
Sex
All
01

Study summary

Routine revascularization of asymptomatic carotid stenosis is questionable as optimal medical therapy has significantly reduced the risk of stroke. Therefore, it is crucial to identify high-risk patients who may still benefit from carotid revascularization. In 2017, the ESC guidelines clarified the criteria associated with a high risk of stroke despite optimal treatment to consider a revascularization procedure, including altered cerebral vasoreactivity. However, cerebral vasoreactivity using transcranial Doppler ultrasound is reserved for qualified centers. It requires a technical platform and trained personnel, is time-consuming and generally not readily available.

A simpler test is therefore necessary. The goal is to quickly and easily detect patients with normal vasoreactivity who do not benefit from the cerebral vasoreactivity test (reference standard) and to reserve the time-consuming cerebral vasoreactivity test for patients likely to have altered vasoreactivity.

The hypothesis of the study is that on a routine measure in transcranial echo-Doppler, the resistance index (RI), can predict the response to the cerebral vasoreactivity test. With this new test, it will be possible to select patients who do not benefit from pharmacological cerebral vasoreactivity testing ("true negatives"). Thus, the time-consuming cerebral vasoreactivity test will be reserved only for patients with a possibility of impaired vasoreactivity.

02

Conditions studied

  • Stenosis
  • Occlusion

Keywords

  • Acetazolamide
03

In context

Constriction, Pathologic

456 studies on the registry are indexed under Constriction, Pathologic; 109 are open to participants now.

This study's planned enrollment of 77 is close to the median of 84 across 144 observational studies indexed under Constriction, Pathologic.

Browse Constriction, Pathologic studies →

Lead sponsor

Centre Hospitalier Universitaire de Nīmes is the lead sponsor of 595 studies on the registry; 90 are open to participants now.

Browse Centre Hospitalier Universitaire de Nīmes studies →

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Non-probability sample

Study population

The study will be carried out at the University Hospital of Nîmes in the department of explorations and vascular medicine (EMV), for patients referred for HRV measurement with a significant stenosis or occlusion.

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • The patient must have given their free and 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

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
  • 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.
Terms in these criteria, in plain language(2)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Contraindication

A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.

05

Study design

Observational model
Cohort
Time perspective
Prospective
Enrollment
77 participants (estimated)
Patient registry
No

Groups and cohorts

  • Patients with abnormal vasoreactivity

    Diagnostic Test: Transcranial Doppler

  • Patients with normal vasoreactivity

    Diagnostic Test: Transcranial Doppler

Interventions

  • Diagnostic testTranscranial Doppler

    Measurement of resistance index on the middle cerebral artery (MCA) (index test) and the Holter (reference test). Patients will be randomized for order of tests

06

What researchers measure

Primary outcomes

  1. Specificity of the difference in average resistance index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  2. Sensitivity of the difference in average resistance index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  3. Positive predictive value of the difference in average resistance index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  4. Negative predictive value of the difference in average resistance index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

Secondary outcomes

  1. Sensitivity of the difference in average Gosling's pulsatility index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  2. Specificity of the difference in average Gosling's pulsatility index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  3. Positive predictive value of the difference in average Gosling's pulsatility index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  4. Negative predictive value of the difference in average Gosling's pulsatility index (delta) between the middle cerebral artery (MCA) on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity

    normal vasoreactivity defined as an increase in the mean of the maximum velocities \> 30% measured by the cerebral vasoreactivity reference test

    Time frame: Day 1

  5. Correlation between delta resistance index and percentage response of vasoreactivity reference test

    correlation coefficient

    Time frame: Day 1

  6. Correlation between delta Gosling's pulsatility index and percentage response of vasoreactivity reference test correlation coefficient

    correlation coefficient

    Time frame: Day 1

  7. Sensitivity of the difference in average Gosling's pulsatility index (delta) between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  8. Specificity of the difference in average Gosling's pulsatility index (delta) between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  9. Positive predictive value oof the difference in average Gosling's pulsatility index (delta) between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  10. Negative predictive value of the difference in average Gosling's pulsatility index (delta) between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  11. Sensitivity of the difference in average resistance index between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  12. Specificity of the difference in average resistance index between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  13. Positive predictive value of the difference in average resistance index between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

  14. Negative predictive value of the difference in average resistance index between the MCA on the M1 segment contralateral and homolateral to the carotid lesion, to detect normal vasoreactivity in symptomatic versus asymptomatic stenosis

    Time frame: Day 1

07

Study locations

1 of 1 sites recruiting
  • CHU de Nîmes
    Nîmes, France
    Recruiting
    • Anissa Megzari · Contactdrc@chu-nimes.fr · 04.66.68.42.36
    • Sarah Coudray · Principal investigator
    • Antonia Perez Martin · Sub investigator
    • Salim ALLAL, MD · Sub investigator
    • Isabelle AICHOUN · Sub investigator
08

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Jun 2023 (actual). Primary completion is estimated for Jun 2029, 72 months after the start.

Of 52 non-industry observational studies under Constriction, Pathologic, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 19 and three quarters within 62. This study's planned 72 months is above that.

Counting every sponsor, half of 64 studies reached it within 31 months; a quarter within 19 and three quarters within 62.

How these figures are worked out, and which studies are left out of them.

Registered
Mar 10, 2023
First posted
Mar 22, 2023
StartActual
Jun 9, 2023
Primary completionEst.
Jun 2029
CompletionEst.
Jun 2029
Last update
Jul 8, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jul 8, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT05780619
Lead sponsor
Centre Hospitalier Universitaire de Nīmes
Responsible party
Sponsor
First posted
Mar 22, 2023
Start date
Jun 9, 2023
Primary completion
Jun 2029 (estimated)
Completion
Jun 2029 (estimated)
Last update
Jul 8, 2026

Study contacts

Sarah Coudray
Contact
sarah.coudray@chu-nimes.fr
04.66.6833.13
Sarah Coudray
principal investigator · CHU de Nimes

Oversight

FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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