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NCT Number: NCT05051397

CO2 Modulation in Endovascular Thrombectomy for Acute Ischemic Stroke

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.

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Key information

Conditions

Ischemic Stroke, Acute Anesthesia, General Brain Diseases Carbon Dioxide Cardiovascular Diseases Central Nervous System Diseases Cerebrovascular Circulation Cerebrovascular Disorders Ischemic Stroke Nervous System Diseases Stroke Thrombectomy Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

CHU

Clermont-Ferrand, 63000, France

Location status: Recruiting

Location contact

Anna Ferrier, MD

SUB_INVESTIGATOR

Ricardo Moreno, MD

SUB_INVESTIGATOR

Russell Chabanne, MD MSc

CONTACT

[email protected]

Russell Chabanne, MD MSc

PRINCIPAL_INVESTIGATOR

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

  • 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

Treatment and study plan

HYPERCAPNIA

Biological

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

NORMOCAPNIA

Biological

Controlled normocapnia PaCO2 40mmHg under general anesthesia with mechanical ventilation

Primary outcomes

  1. ASITN cerebral vascular collaterality score > 2

    Time frame: Before reperfusion of the occluded vessel

    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.

Secondary outcomes

  1. ASITN cerebral vascular collaterality score

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

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

  2. Volume of cerebral infarction

    Time frame: 24 hours after stroke

    Evaluated with Magnetic Resonance Imaging in milliliters

  3. Progression of cerebral infarction

    Time frame: 24 hours after stroke

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

  4. Neurological clinical outcome

    Time frame: 3 months

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

Other outcomes

  1. Pial Vascular Collaterality within the symptomatic ischemic territory at admission

    Time frame: At admission

    Pial Vascular collaterality evaluated at admission with CT or MRI during patient selection for thrombectomy using the Pial Arterial Filling Score (from 0 indicated no collaterality to 5 indicating excellent collaterality)

  2. Arterial carbon dioxide tension

    Time frame: At groin puncture and at the end of procedure

    Arterial carbon dioxide tension will be measured at 2 time points.

  3. Cerebral infarction extension

    Time frame: Before thrombectomy and at day 1

    The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is an imaging measure of the extent of ischemic stroke. Scores range from 0 to 10, with higher scores indicating a smaller infarct core.

  4. Reperfusion assessed by mTICI

    Time frame: End of procedure

    The modified Treatment In Cerebral Ischemia (mTICI) reperfusion scale ranging from 0 (no perfusion) to 3 (full perfusion with filling of all distal Branches). Good reperfusion will be defined as a score of 2B-3.

  5. Procedural delay

    Time frame: End of procedure

    Time frame from angiosuite admission to groin puncture to reperfusion if any

  6. Number of procedural anesthetic and radiological complications

    Time frame: End of procedure

    Procedural Safety outcomes

  7. Number of Death and neurological complications

    Time frame: Day 7

    Safety outcomes

Study contacts

Contact information is provided by the study sponsor or research team.

Lise Laclautre

CONTACT

[email protected]

+33 4 73 754963

Sponsors and collaborators

Lead sponsor

University Hospital, Clermont-Ferrand

Other

Registry information

Official study 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

Acronym: COMET-AIS

Important dates

Study start
2022
Primary completion
2026
Study completion
2026
First posted
Sep 21, 2021
Registry last updated
Oct 6, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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