Oral Microbiome in Carotid Atherosclerosis (OMICA)

April 21, 2026 updated by: Prof. Dr. Sótonyi Péter, Semmelweis University Heart and Vascular Center

The Role of the Oral Microbiome in Carotid Atherosclerosis: Investigating in a Cross-sectional Study the Microbial Influence on Plaque Development and Vulnerability Based on Biobank Data

The goal of this observational study, called OMICA (Oral Microbiome in Carotid Atherosclerosis), is to learn how bacteria living in the mouth may influence the development and stability of plaques in the carotid arteries, which supply blood to the brain. Plaque buildup in these arteries can lead to stroke.

Researchers want to understand whether certain oral bacteria are linked to plaque vulnerability, meaning a higher chance that the plaque will rupture and cause a stroke.

The study will include a cohort of adults scheduled for carotid endarterectomy at Semmelweis University. Participants will be enrolled in the Semmelweis University Carotid Biobank project.

The main questions the study aims to answer are:

Do people with more severe gum disease or tooth infection have a higher number of bacteria in their carotid plaques, and are those plaques more likely to rupture?

Are the bacteria found in vulnerable plaques different from those in stable plaques?

Are similar bacteria found in the mouth, gut, and plaques, suggesting that bacteria may travel through the body?

What participants will do:

Have their oral health checked before surgery, including an exam of gum disease and tooth infections.

Provide microbiome samples from the mouth, anus, urine, and carotid plaque (taken during surgery).

Have preoperative photon-counting computed tomography (CT) performed to assess plaque stability and study eligibility.

All samples and imaging data will be analyzed to identify bacterial species and their relationship to plaque type.

The study does not involve any experimental treatment or medication. Participation adds no significant medical risk beyond standard care.

Researchers will compare bacterial patterns between people with vulnerable plaques and those with stable plaques to identify microbial signatures linked to carotid plaque instability.

The results may help create future microbiome-based risk models for detecting people at higher risk of stroke or severe atherosclerosis.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Background and Rationale: Cardiovascular diseases are currently the leading cause of death globally, according to the World Health Organization. Recent studies report a 4.2% prevalence of moderate to severe carotid artery stenosis. A growing body of evidence highlights the association between poor oral health and vascular disease. Periodontitis is a highly prevalent condition, affecting approximately 10% of the global population with its severe form (1). Several studies have revealed correlations between the severity of periodontal disease and the presence of pathogenic bacteria in carotid (2) and atherosclerotic plaques (3).

Methods:

Population: The cross-sectional study includes a cohort of patients undergoing carotid endarterectomy: roughly half with vulnerable and half with stable carotid plaques. Photon-counting computed tomography (CTA) is part of the preoperative eligibility assessment confirming internal carotid artery stenosis and determining inclusion in the study. Only non-invasive magnetic resonance (MR) and ultrasound imaging will be requested from participants as part of the study protocol for classification of plaque vulnerability. All imaging data will be anonymized in accordance with Semmelweis University data protection protocols.

Intervention (Sample Collection): This study involves preoperative oral health evaluation and the collection of oral, anal, urine, blood, and carotid plaque samples during carotid endarterectomy for microbiome analysis. All samples and corresponding data will be fully anonymized and processed within the Semmelweis University Carotid Plaque Biobank (BM/33955-1/2023).

Comparator: Patients with vulnerable vs. stable carotid plaques, as classified by carotid duplex ultrasound (GSM score) and photon-counting CTA and MR plaque characterization.

Outcome:

  1. Identification of periodontal and endodontic pathogens in the oral microbiome that positively correlate with plaque severity and vulnerability.
  2. Distinct microbiome compositions in carotid plaques of patients with stable versus vulnerable lesions, supporting the role of bacterial colonization in plaque instability.
  3. Detection of microbiome similarities across oral, anal, and vascular samples, suggesting systemic bacterial dissemination that may contribute to carotid stenosis progression.

Expected Value of Results: This project integrates microbiome and imaging data to explore links between oral bacteria and carotid plaque vulnerability. By investigating the interplay between oral microbiota and vascular disease, the study aims to deepen our understanding of plaque pathogenesis and progression. The findings may contribute to developing microbiome-based risk prediction models for plaque vulnerability, supported by advanced imaging data.

Study Type

Observational

Enrollment (Estimated)

200

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 Contact Backup

Study Locations

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

No

Sampling Method

Non-Probability Sample

Study Population

Participants will be recruited from patients undergoing carotid endarterectomy at Semmelweis University, Budapest, Hungary, within the framework of the Semmelweis Carotid Plaque Biobank. Eligible individuals are adults with confirmed internal carotid artery stenosis identified by photon-counting CT angiography. Enrollment is consecutive among surgical candidates who provide informed consent. The study population reflects a tertiary vascular surgery center cohort representing both stable and vulnerable plaque phenotypes, as classified by ultrasound, MR, and CTA imaging.

Description

Inclusion Criteria:

  • Confirmed internal carotid artery (ICA) stenosis on preoperative photon-counting computed tomography (CTA)
  • Adults (≥18 years) undergoing carotid endarterectomy at Semmelweis University.
  • Eligible for surgery based on standard anesthesiologic evaluation.
  • Willing and able to provide written informed consent for participation and sample collection.

Exclusion Criteria:

  • Active systemic infection or current antibiotic therapy within 30 days before surgery.
  • Immunosuppressive therapy or immunodeficiency disorders.
  • Inability to undergo MRI (e.g., pacemaker, metallic implants, severe claustrophobia).
  • Pregnancy or lactation.
  • Malignancy under active treatment.
  • Prior carotid surgery or stenting on the same side.
  • Refusal or inability to provide informed consent.

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
Vulnerable Plaque Group
Participants with vulnerable carotid plaques, identified based on ultrasound gray-scale median (GSM) score, photon-counting CT angiography, and MR plaque characterization.
Other: Sample Collection
Participants undergo preoperative oral health evaluation and the collection of oral, anal, urine, blood, and carotid plaque samples during carotid endarterectomy for microbiome analysis. All samples are fully anonymized and processed within the Semmelweis University Carotid Plaque Biobank (BM/33955-1/2023). No experimental treatments are administered; all activities occur within the framework of biobank-approved surgical and diagnostic procedures.
Other Names:
  • Oral-Systemic Microbiome Analysis
  • Carotid Plaque Microbiome Sampling
Stable Plaque Group
Participants with stable carotid plaques, classified by imaging criteria indicating low vulnerability.
Other: Sample Collection
Participants undergo preoperative oral health evaluation and the collection of oral, anal, urine, blood, and carotid plaque samples during carotid endarterectomy for microbiome analysis. All samples are fully anonymized and processed within the Semmelweis University Carotid Plaque Biobank (BM/33955-1/2023). No experimental treatments are administered; all activities occur within the framework of biobank-approved surgical and diagnostic procedures.
Other Names:
  • Oral-Systemic Microbiome Analysis
  • Carotid Plaque Microbiome Sampling

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Identification of Oral and Carotid Plaque Microbiome Associations
Time Frame: At time of carotid endarterectomy
Microbiome composition of oral and carotid plaque samples will be analyzed using next-generation sequencing to identify bacterial taxa correlated with plaque vulnerability. Relative abundance and diversity indices will be compared between participants with vulnerable and stable carotid plaques to determine microbial associations linked to plaque instability.
At time of carotid endarterectomy

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Differences in Microbiome Composition Between Vulnerable and Stable Carotid Plaques
Time Frame: At time of carotid endarterectomy
Microbial diversity, relative abundance, and taxonomic composition of carotid plaque samples will be compared between vulnerable and stable plaques using 16S rRNA gene sequencing and bioinformatic analysis. Results will help identify microbial signatures associated with plaque stability or vulnerability.
At time of carotid endarterectomy
Identification of Shared Microbial Taxa Across Oral, Anal, Urine, and Carotid Plaque Samples
Time Frame: At time of carotid endarterectomy
Microbiome overlap among oral, anal, urine, and carotid plaque samples will be analyzed to detect bacterial species present across multiple body sites, indicating possible systemic dissemination pathways linked to atherosclerotic plaque progression.
At time of carotid endarterectomy

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Correlation Between Oral Health Status and Carotid Plaque Vulnerability
Time Frame: Within 2 weeks prior to carotid endarterectomy
Clinical periodontal indices (probing depth, attachment loss, and periapical lesion presence) will be correlated with imaging-defined plaque vulnerability scores to evaluate whether oral disease severity predicts plaque instability.
Within 2 weeks prior to carotid endarterectomy

Collaborators and Investigators

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

Sponsor

Semmelweis University Heart and Vascular Center

Collaborators

National Research, Development and Innovation Office, Hungary

Investigators

  • Principal Investigator: Péter Sótonyi, MD, DSc, Semmelweis University Heart and Vascular Center

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

Helpful Links

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)

November 1, 2025

Primary Completion (Estimated)

November 1, 2027

Study Completion (Estimated)

November 1, 2029

Study Registration Dates

First Submitted

November 24, 2025

First Submitted That Met QC Criteria

December 8, 2025

First Posted (Actual)

December 22, 2025

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 21, 2026

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NKFI-Advanced 149634 (Other Grant/Funding Number: National Research, Development, and Innovation Office)
  • BM/33955-1/2023 (Other Identifier: Semmelweis University Carotid Plaque Biobank)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data (IPD) will be de-identified and may be shared with qualified researchers upon reasonable request following completion of the study and publication of primary results, pending ethical and institutional approval.

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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