Investigation of Brain Blood Flow Changes in Acute Ischemic Stroke Patients After Successful Endovascular Thrombectomy

NCT07534319 | Recruiting DMC

• 1 other identifier: BASEC2024-00947
• Study Type: observational
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

Introduction: Endovascular thrombectomy (EVT) is an effective treatment strategy to mitigate the ischemic tissue damage caused by the acute cerebral large-vessel occlusion. However, in clinical practice, nearly half of the patients do not experience adequate neurological improvement despite successful recanalization - a phenomenon termed reperfusion failure or clinically ineffective reperfusion. Given the clinical relevance of this phenomenon and the absence of a standardized imaging diagnostic method to identify it, our project aims to explore the potential role of blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) as novel imaging biomarker for studying reperfusion failure. Study population: Adult patients with acute ischemic stroke of the ICA, MCA or with tandem occlusion who have undergone a successful recanalization, described as mTICI score ≥2b. Objective(s): Primary objective: to longitudinally observe blood flow changes derived from BOLD-CVR imaging following successful endovascular thrombectomy in patients with large-vessel occlusion acute ischemic stroke (LVO-AIS) during the early post-treatment phase and assess their association with clinical outcome 90 days post-EVT. Secondary objective: to compare BOLD-CVR findings with those obtained from the clinical standard dynamic susceptibility contrast (DSC) MR perfusion imaging acquired in the same examination session as well as other imaging techniques included in the standard post-treatment imaging protocol at our institution. Outcomes: Clinical outcomes:

• 90-day functional outcome.
• Functional outcome at hospital discharge.
• Neurological deterioration during hospitalization.
• Radiologically confirmed haemorrhagic transformation within the reperfused tissue.
• Radiologically confirmed infarct lesion progression within the reperfused tissue.
• Additionally, DSC MR perfusion imaging parameters and other standard hemodynamic imaging parameters will be considered as imaging outcomes Study design: Single-center prospective observational cohort study Measurements and procedures: Included patients will undergo a total of 3 BOLD-CVR examinations: 72 hours, 7 days, and 90 days after EVT. Participation in the final examination will mark the end of the subject's involvement in the study. Clinical outcomes will be prospectively collected as per established institutional patient management protocols: during hospitalization, at discharge, and at the cerebrovascular outpatient clinic at 3 months. Number of Participants: Target sample size: 100 patients Given the observational study design and exploratory nature of this project, no sample size calculation can be performed. The provided target sample size (N = 100) has been estimated considering the inclusion of as many consecutive subjects as possible. Study period: 2.5 years The investigators aim to enroll a target sample size of 100 patients over a period of 2.5 years. This translates to an inclusion of 3-4 patients per month, with the last three months allocated for the follow-up of the last included patients. Study Centre: Clinical Neuroscience Center, Department of Neurosurgery, University Hospital Zurich Statistical Considerations: The association between BOLD-CVR findings and clinical outcomes will be investigated using regression analyses.

Conditions

Acute Cerebrovascular Accident; Thrombectomy; Cerebral Revascularization; No Reflow Phenomenon

Keywords

Acute Ischemic Stroke; Thrombectomy; Reperfusion Failure; Cerebral Revascularization; No Reflow Phenomenon; BOLD-CVR; Advanced Haemodynamic Imaging

Outcome Measures

Primary Outcomes (1)

• Comparison of the BOLD-CVR signal with the functional outcome at 3 months

  Following a published pipeline, BOLD-CVR values per voxel are obtained through a voxel-wise linear regression analysis between the end-tidal CO₂ time course and the BOLD fMRI signal time course. BOLD-CVR is expressed as the percent BOLD signal change per mmHg CO₂ (%BOLD signal change/mmHg CO₂).9 Predefined anatomical brain masks are applied to delineate three regions of interest: the whole brain, the ipsilateral hemisphere, and the territory of the middle cerebral artery (MCA). These masks are overlaid on the BOLD-CVR maps, and the average BOLD-CVR value is calculated for each region, resulting in average BOLD-CVR values for the whole brain, the ipsilateral hemisphere, and the MCA territory. The functional outcome at 90 days post-EVT will be assessed with the mRS score.

  Comparison of the BOLD CVR signal obtained in the MRI performed within 72 hours after thrombectomy with the functional outcome at three months after intervention (mRS)

Secondary Outcomes (9)

• Comparison of the BOLD-CVR signal with the dynamic susceptibility contrast (DSC) MR perfusion imaging signal parameters

  With 72 hours after thrombectomy; Within 1 week after thrombectomy; at 90 days after thrombectomy.

• Comparison of the BOLD-CVR Signal with the Quantitative Digital Subtraction Angiography signs

  Comparison of the BOLD-CVR signal performed 72 hours after thrombectomy with the intraprocedural quantitative Digital Subtraction Angiography signs (ex. capillary blush, early venous filling, etc.)

• Comparison of the BOLD CVR signal with the National Institutes of Health Stroke Scale (NIHSS)

  at 7 days

• Comparison of the BOLD-CVR signal with the Modified Rankin Scale (MRS)

  at 7 days

• Comparison of the BOLD CVR Signal with neurological deterioration during hospitalization

  Time Frame between the thrombectomy and 7 days post-EVT

Study Arms (1)

Patients with an acute ischemic stroke of the ICA, MCA or both with successful revascularization

* Male and female subjects \>18 years old. * Acute ischemic stroke related to a new occlusion of the internal carotid artery, middle cerebral artery (M1- and/or M2-segment), or both. * Eligibility and performance of endovascular thrombectomy. * Achievement of successful recanalization, defined as mTICI score ≥2b * Written informed consent of the patient or when the patient is not able to participate in the consenting procedure, the written authorization of an independent doctor not involved in the research project is requested to safeguard the interests of the patients (in that case, post hoc written informed consent of the patient or next of kin had to be obtained). Foreign speaking patients should be included by a person with sufficient German language proficiency to act as a translator.

Other: No planned intervention

Interventions

No planned intervention OTHER

No planned intervention

Patients with an acute ischemic stroke of the ICA, MCA or both with successful revascularization

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Probability Sample

Study Population

Patients with an acute ischemic stroke of the ICA, MCA or with tandem occlusion who have had a successful recanalization, defined as mTICI score ≥2b and with written informed consent of the patient or a family member

You may qualify if:

• Male and female subjects \>18 years old.
• Acute ischemic stroke related to a new occlusion of the internal carotid artery, middle cerebral artery (M1- and/or M2-segment), or both.
• Eligibility and performance of endovascular thrombectomy.
• Achievement of successful recanalization, defined as mTICI score ≥2b
• Written informed consent of the patient or when the patient is not able to participate in the consenting procedure, the written authorization of a family member. Foreign speaking patients should be included by a person with sufficient German language proficiency to act as a translator.

You may not qualify if:

• Documented evidence or a confirmed willingness of the patient not to participate in any scientific study.
• Standard contraindications for MRI, such as pacemaker, metallic prothesis, glaucoma, metallic tattoo dyes, verbal confirmed pregnancy. Unwilling or unable to cooperate with breathing manoeuvres.
• Major cardiopulmonary diseases, such as severe uncontrolled asthma bronchiale, severe chronic obstructive lung disease (i.e., GOLD stage ≥III), diffuse interstitial lung disease, pulmonary embolism, acute/subacute myocardial infarction, or severe heart failure (i.e., NYHA class ≥III).
• Symptomatic increased intracranial pressure.
• Presence of intracranial haemorrhage type ≥2 according to the Heidelberg classification.
• New onset of seizure.

Sponsors & Collaborators

• University of Zurich: lead

Study Sites (1)

Zurich University Hospital

Zurich, Canton of Zurich, 8006, Switzerland

RECRUITING

Related Links

• Website of the BOLD-CVR research group from Zurich

MeSH Terms

Conditions

Stroke; No-Reflow Phenomenon; Ischemic Stroke

Condition Hierarchy (Ancestors)

Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Ischemia; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Jorn Fierstra, Prof Dr. med., PhD

  University of Zurich

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Meltem Gönel, Dr. med.

CONTACT

43 253 90 19; meltem.goenel@usz.ch

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof Dr. med., PhD

Study Record Dates

• First Submitted: March 26, 2026
• First Posted: April 16, 2026
• Study Start: June 1, 2025
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): December 1, 2027
• Last Updated: April 16, 2026

Record last verified: 2026-04

Locations

CH (1)