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Ischemic Stroke, AcutePhase 2COMET-AISNCT05051397

CO2 Modulation in Endovascular Thrombectomy for Acute Ischemic Stroke

A Phase 2 study testing HYPERCAPNIA and NORMOCAPNIA in people with Ischemic Stroke, Acute and Thrombectomy, run by University Hospital, Clermont-Ferrand at 1 site in France.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

Acute ischemic stroke due to large vessel occlusion is responsible of cerebral blood flow impairment with a progressive and extensive ischemic process. Cerebral collateral circulation may preserve an ischemic penumbra that could recover providing timely reperfusion of the occluded vessel. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
HYPERCAPNIA and NORMOCAPNIA
Could I receive a placebo?
No, everyone receives an active treatment
How many people
50 participants
Where
1 siteFrance
Study dates
20 Jul 2022to 20 Oct 2028
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Large vessel occlusion anterior circulation stroke (terminal carotid artery and/or middle cerebral artery M1-M2 segment) eligible to mechanical thrombectomy under general anesthesia

Who cannot join

  • Active smoker
  • Chronic respiratory failure with ambulatory oxygen supplementation
  • Obesity with BMI>40Kg/ m2
  • Intubation before the procedure
  • Heart failure with intolerance to decubitus
  • Severe renal failure
  • Suspected elevated intracranial pressure
  • Pregnant or breastfeeding women

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Lise Laclautre contact

+33 4 73 754963

promo_interne_drci@chu-clermontferrand.fr

France1 site, 1 recruiting

  • CHU

    Clermont-Ferrand, 63000

    Russell Chabanne, MD MSc, rchabanne@chu-clermontferrand.fr

    Russell Chabanne, MD MSc

    Recruiting

Other trials in France

About this study

Official title: Evaluation of the Effect of Moderate and Controlled Hypercapnia on Ischemic Penumbra Vascular Collaterality During General Anesthesia for Anterior Circulation Acute Ischemic Stroke Mechanical Thrombectomy

Acute ischemic stroke due to large vessel occlusion is responsible of cerebral blood flow impairment with a progressive and extensive ischemic process. Cerebral collateral circulation may preserve an ischemic penumbra that could recover providing timely reperfusion of the occluded vessel. Mechanical thrombectomy is the standard of care for anterior circulation large vessel reperfusion. Strategy to promote cerebral blood flow in collateral circulation before reperfusion is scarce and rely mainly on blood pressure maintenance. Carbon dioxide is a potent cerebral vasodilator that could enhance collateral circulation blood flow and cerebral protection before reperfusion. General anesthesia with endotracheal mechanical ventilation could be used for thrombectomy and give the opportunity to modulate and control carbon dioxide tension in the blood. This study will test the effect of moderate hypercapnia on penumbral collateral circulation before reperfusion during mechanical thrombectomy for anterior circulation acute ischemic stroke under general anesthesia.

Read the detailed description

Study will compare 2 groups of patients treated for anterior circulation large vessel occlusion stroke thrombectomy under general anesthesia.

After anesthetic evaluation, patients will be randomized to receive moderate hypercapnia targeting an arterial CO2 tension (PaCO2) of 50mmHg or normocapnia targeting a PaCO2 of 40mmHg.

The anesthetic protocol will use:

  • Rapid sequence induction for orotracheal intubation with PROPOFOL 2mg/Kg and SUXAMETHONIUM 1mg/Kg
  • SUFENTANIL 0,1 µg/Kg and CISATRACURIUM 0,1mg/Kg
  • Maintenance with intravenous continuous infusion of PROPOFOL targeting a BISpectral index 40 to 60
  • Systolic blood pressure will have to be maintained +/- 10% of preoperative baseline value with limits between 120 and 185mmHg (with NOREPINEPHRINE as needed)
  • Mechanical ventilation will use Tidal Volume of 7mL/Kg of ideal body weight, respiratory rate of 15/minute, End expiratory pressure of 5cmH2O. FiO2 will target SpO2 95-98%. Initial End Tidal CO2 (EtCO2) target will be 35mmHg.
  • A first arterial blood gas analysis at groin puncture will evaluate CO2 alveolar-arterial gradient in order to obtain the expected PaCO2 in each group with respiratory rate modulation on the ventilator.
  • ASITN baseline collaterality score will be evaluated at initial angiography with normocapnia in each group. A second evaluation of ASITN will be done just before deployment of intraarterial revascularisation device in hypercapnia or normocapnia depending on randomisation group.
  • Targeted PaCO2 will have to be maintained using EtCO2 surrogate until the end of procedure.
  • A second arterial blood gas analysis at the end of procedure will evaluate final PaCO2.
Being tested
HYPERCAPNIA, NORMOCAPNIA
Keywords
mechanical thrombectomy, large vessel occlusion stroke, carbon dioxide tension, cerebral blood flow, general anesthesia, cerebral collateral circulation
Medical subject headings
Ischemic Stroke

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • HYPERCAPNIABiological

    Controlled moderate hypercapnia PaCO2 50mmHg under general anesthesia with mechanical ventilation

  • NORMOCAPNIABiological

    Controlled normocapnia PaCO2 40mmHg under general anesthesia with mechanical ventilation

Study groups in NCT05051397
Study groupRoleWhat they receive
HYPERCAPNIAExperimentalUnder general anesthesia with mechanical ventilation, PaCO2=50mmHg will be targeted
Receives: Biological: HYPERCAPNIA
NORMOCAPNIAActive comparatorUnder general anesthesia with mechanical ventilation, PaCO2=40mmHg will be targeted
Receives: Biological: NORMOCAPNIA

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. ASITN cerebral vascular collaterality score > 2

    American Society of Interventional and Therapeutic Neuroradiology (ASITN) cerebral vascular collaterality score ranges from 0 (no collaterals visible to the ischemic site) to 4 (complete and rapid collateral blood flow to the vascular bed in the entire ischemic territory by retrograde perfusion). A score > 2 indicate at least collaterals with slow but complete angiographic blood flow of the ischemic bed by the late venous phase.

    Measured: Before reperfusion of the occluded vessel

Secondary outcomes (4)

  1. ASITN cerebral vascular collaterality score

    American Society of Interventional and Therapeutic Neuroradiology (ASITN) variation during the procedure

    Measured: • At initial angiography in normocapnia and • Before reperfusion at randomized arterial CO2 tension level

  2. Volume of cerebral infarction

    Evaluated with Magnetic Resonance Imaging in milliliters

    Measured: 24 hours after stroke

  3. Progression of cerebral infarction

    Evaluated with Magnetic Resonance Imaging or Computed Tomography in milliliters depending on type of radiological modality for patient selection

    Measured: 24 hours after stroke

  4. Neurological clinical outcome

    Ordinal and dichotomized modified rankin scale (mRS) ranging from 0 (no disability) to 6 (death); good outcome will be defined as mRS 0-2.

    Measured: 3 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted21 Sep 2021
  2. Study start20 Jul 2022
  3. Primary completion20 Oct 2028 (estimated)
  4. Study completion20 Oct 2028 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Double blind
Who is masked
Participant, Outcomes assessor
Enrolment
50 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05051397
Sponsor's protocol ID
COMET-AIS (AOI 2020 Chabanne)
Other IDs
AOI...
Acronym
COMET-AIS
Status last verified
Aug 2026
First submitted
9 Jul 2021
Last updated
3 Sep 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No

Publications

  • Schonenberger S, Henden PL, Simonsen CZ, Uhlmann L, Klose C, Pfaff JAR, Yoo AJ, Sorensen LH, Ringleb PA, Wick W, Kieser M, Mohlenbruch MA, Rasmussen M, Rentzos A, Bosel J. Association of General Anesthesia vs Procedural Sedation With Functional Outcome Among Patients With Acute Ischemic Stroke Undergoing Thrombectomy: A Systematic Review and Meta-analysis. JAMA. 2019 Oct 1;322(13):1283-1293. doi: 10.1001/jama.2019.11455.

    PubMed 31573636

  • Slupe AM, Kirsch JR. Effects of anesthesia on cerebral blood flow, metabolism, and neuroprotection. J Cereb Blood Flow Metab. 2018 Dec;38(12):2192-2208. doi: 10.1177/0271678X18789273. Epub 2018 Jul 16.

    PubMed 30009645

  • Powers WJ, Rabinstein AA, Ackerson T, Adeoye OM, Bambakidis NC, Becker K, Biller J, Brown M, Demaerschalk BM, Hoh B, Jauch EC, Kidwell CS, Leslie-Mazwi TM, Ovbiagele B, Scott PA, Sheth KN, Southerland AM, Summers DV, Tirschwell DL; American Heart Association Stroke Council. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2018 Mar;49(3):e46-e110. doi: 10.1161/STR.0000000000000158. Epub 2018 Jan 24.

    PubMed 29367334

  • Willie CK, Macleod DB, Shaw AD, Smith KJ, Tzeng YC, Eves ND, Ikeda K, Graham J, Lewis NC, Day TA, Ainslie PN. Regional brain blood flow in man during acute changes in arterial blood gases. J Physiol. 2012 Jul 15;590(14):3261-75. doi: 10.1113/jphysiol.2012.228551. Epub 2012 Apr 10.

    PubMed 22495584

  • Olsen TS, Larsen B, Herning M, Skriver EB, Lassen NA. Blood flow and vascular reactivity in collaterally perfused brain tissue. Evidence of an ischemic penumbra in patients with acute stroke. Stroke. 1983 May-Jun;14(3):332-41. doi: 10.1161/01.str.14.3.332.

    PubMed 6658900

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing HYPERCAPNIA and NORMOCAPNIA in people with Ischemic Stroke, Acute and Thrombectomy, run by University Hospital, Clermont-Ferrand at 1 site in France.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 3 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Lise Laclautre (+33 4 73 754963, promo_interne_drci@chu-clermontferrand.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

ASITN cerebral vascular collaterality score > 2 (time frame: Before reperfusion of the occluded vessel). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05051397, which also lists 5 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Sep 2026.

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