Ocular Perfusion in Patients With Unilateral Carotid Artery Stenosis

May 2, 2024 updated by: Gerhard Garhofer, Medical University of Vienna
The aim of the presented study is to evaluate ocular blood flow, respectively optic nerve head blood flow in patients with carotid artery stenosis before and after carotid endarterectomy or carotid artery stenting. Additionally, the investigators aim to compare optic nerve head blood flow in patients with CAS and healthy age- and sex-matched control subjects. Furthermore, the investigators intend to evaluate brain tissue oxygenation in patients with carotid artery stenosis before, during and after CEA and carotid artery stenting. Finally, the investigators will assess potential correlations between LSFG and NIRS results in patients with unilateral carotid artery stenosis.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Carotid artery stenosis is a condition that can lead to severe consequences such as ocular ischemia or stroke. As the ophthalmic artery branches off the carotid artery, ocular ischemic complications include amaurosis fugax, ocular ischemic syndrome or central retinal artery occlusion. Hence, early diagnosis of carotid artery stenosis and ocular perfusion impairment is of considerable importance to prevent ocular and systemic ischemic complications.

As the retina offers a unique window for examining the microcirculation in a non-invasive manner, several imaging techniques have already been used in recent years to assess ocular alterations associated with carotid artery stenosis. However, these examination techniques have their limitations and are therefore not suitable methods for determining ocular perfusion. On the contrary, Laser Speckle Flowgraphy (LSFG) is a non-invasive, in-vivo imaging method which quantitatively estimates blood flow in the optic nerve head, the choroid, the retina and the iris. LSFG offers a promising alternative from conventional methods, as it eliminates the need for contrast agents, has a low procedural complexity and obtains precise and reproducible measurements.

As the eye and brain share a close vascular relationship, both receiving blood supply from branches of the internal carotid artery, there is potential to establish a correlation between cerebral and ocular hemodynamics. Near-infrared spectroscopy (NIRS) is a simple and non-invasive method which enables continuous assessment of cerebral oxygenation. However, data on the course of oxygenation of the brain tissue using NIRS before, during and after carotid interventions are scarce. Additionally, there is a lack of comparative NIRS data between carotid endarterectomy (CEA) and carotid artery stenting. Furthermore, correlation studies between oxygenation of the brain tissue and ocular perfusion are largely missing.

Hence, the aim of this study is to evaluate optic nerve head blood flow in patients with carotid artery stenosis before and after CEA or carotid artery stenting. Additionally, the investigators will compare optic nerve head blood flow in patients with carotid artery stenosis to healthy sex- and age-matched control subjects. Furthermore, the investigators intend to evaluate brain tissue oxygenation in patients with carotid artery stenosis before, during and after CEA and carotid artery stenting. Finally, the investigators will assess potential correlations between LSFG and NIRS results in patients with unilateral carotid artery stenosis.

Study Type

Observational

Enrollment (Estimated)

45

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Austria
      • Vienna, Austria, 1090
        • Recruiting
        • Department of Clincal Pharmacology, Medical University of Vienna
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

N/A

Sampling Method

Non-Probability Sample

Study Population

A total of 45 patients will be included in the study:

  • 15 subjects with unilateral carotid artery stenosis and planned CEA
  • 15 subjects with unilateral carotid artery stenosis and planned carotid artery stenting
  • 15 healthy age- and sex-matched control subjects

Description

Inclusion Criteria for patients with unilateral carotid artery stenosis:

  • Men and Women aged ≥ 18 years
  • Signed informed consent
  • Normal ophthalmic findings, unless the investigator considers an abnormality to be clinically irrelevant
  • Diagnosis of unilateral carotid artery stenosis and scheduled carotid endarterectomy or carotid artery stenting

Inclusion criteria for healthy age- and sex-matched control subjects:

  • Men and Women aged ≥ 18 years
  • Signed informed consent
  • Normal ophthalmic findings, unless the investigator considers an abnormality to be clinically irrelevant
  • Normal findings in the medical history, unless the investigator considers an abnormality to be clinically irrelevant
  • Non-Smokers

Exclusion criteria for patients with carotid artery stenosis and healthy age- and sex-matched control subjects:

  • Blood donation in the three weeks preceding the study
  • Symptoms of a clinically relevant illness in the three weeks preceding the study
  • Ocular inflammation or infection within the last 3 months
  • History of family history of epilepsy
  • Diabetes mellitus type 1 or type 2
  • Pregnant or breast-feeding women
  • Women of childbearing potential (neither menopausal, nor hysterectomized, nor sterilized) not using effective contraception

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Carotid endarterectomy (CEA) (Group 1)
Subjects with unilateral carotid artery stenosis and planned CEA
Procedure: Carotid endarterectomy (CEA)
Carotid endarterectomy (CEA): Surgical procedure to remove the plaque buildup in the carotid artery.
Carotid artery stenting (Group 2)
Subjects with unilateral carotid artery stenosis and planned carotid artery stenting
Procedure: Carotid artery stenting
Carotid artery stenting: Treatment of the stenosis with a stent. The plaque in the artery wall is not removed but the narrowing is dilated.
Healthy Control Group (Group 3)
Healthy age- and sex-matched control subjects

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Optic nerve head blood flow
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in optic nerve head blood flow (LSFG) in patients with unilateral carotid artery stenosis before and after carotid endarterectomy or carotid artery stenting
Before and 4-6 weeks after CEA or carotid artery stenting

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Retinal oxygen saturation and retinal vessel diameter
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in retinal oxygen saturation and retinal vessel diameter (retinal oximetry)
Before and 4-6 weeks after CEA or carotid artery stenting

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Neurovascular coupling
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in neurovascular coupling (retinal stimulation with flickering-light)
Before and 4-6 weeks after CEA or carotid artery stenting
Retinal nerve fiber layer thickness
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in retinal nerve fiber layer thickness (OCT)
Before and 4-6 weeks after CEA or carotid artery stenting
Retinal thickness
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in retinal thickness (OCT)
Before and 4-6 weeks after CEA or carotid artery stenting
Retinal vessel density
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in retinal vessel density (OCT-A)
Before and 4-6 weeks after CEA or carotid artery stenting
Choroidal vascularity index
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in choroidal vascularity index (EDI-OCT)
Before and 4-6 weeks after CEA or carotid artery stenting
Optic nerve head blood flow
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in optic nerve head blood flow (LDF)
Before and 4-6 weeks after CEA or carotid artery stenting
OPP and arterial BP
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in ocular perfusion pressure and arterial blood pressure
Before and 4-6 weeks after CEA or carotid artery stenting
Brain tissue oxygenation
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Change in brain tissue oxygenation (NIRS) before, during and after CEA or carotid artery stenting
Before and 4-6 weeks after CEA or carotid artery stenting
NIRS and LSFG
Time Frame: Before and 4-6 weeks after CEA or carotid artery stenting
Correlation between optic nerve head blood flow and brain tissue oxygenation before and after CEA or carotid artery stenting (LSFG and NIRS)
Before and 4-6 weeks after CEA or carotid artery stenting

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 9, 2024

Primary Completion (Estimated)

May 2, 2026

Study Completion (Estimated)

May 2, 2026

Study Registration Dates

First Submitted

April 22, 2024

First Submitted That Met QC Criteria

May 2, 2024

First Posted (Actual)

May 3, 2024

Study Record Updates

Last Update Posted (Actual)

May 3, 2024

Last Update Submitted That Met QC Criteria

May 2, 2024

Last Verified

May 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • OPHT-101023

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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