Impact of TAVI on the Gut Microbiota and Its Metabolites (Swiss-GUT-TAVI)

May 4, 2026 updated by: Insel Gruppe AG, University Hospital Bern

Impact of Transcatheter Aortic Valve Implantation on the Composition and Function of the Gut Microbiota

Aortic stenosis is a common heart valve disease in older adults. It occurs when the aortic valve becomes narrowed, making it harder for blood to flow from the heart to the rest of the body. Without treatment, this condition can lead to serious complications and reduced survival. A widely used treatment is transcatheter aortic valve implantation (TAVI), a minimally invasive procedure that replaces the diseased valve and improves blood flow.

Recent research suggests that heart diseases, including aortic stenosis, may affect the gut (intestinal) environment. The gut contains trillions of microorganisms (called the gut microbiota) that play an important role in digestion, immunity, and overall health. In patients with heart conditions, reduced blood flow may impair the intestinal barrier and alter the balance of these microorganisms. This imbalance may contribute to inflammation and other complications.

This study aims to better understand how aortic stenosis and its treatment with TAVI influence the gut microbiota and intestinal health. Researchers will measure specific substances produced by gut bacteria (called metabolites) in blood and stool samples. These include bile acids, trimethylamine N-oxide (TMAO), tryptophan-related compounds, and short-chain fatty acids.

Samples will be collected before and three months after the TAVI procedure. In addition, genetic analysis of stool samples will be performed to identify and compare the types of bacteria present before and after treatment.

The goal is to determine whether improving heart function with TAVI can restore a healthier gut environment. This may help identify new ways to improve outcomes and reduce complications in patients with aortic stenosis.

Study Overview

Status

Active, not recruiting

Conditions

Study Type

Observational

Enrollment (Actual)

40

Contacts and Locations

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

Study Locations

  • Switzerland
      • Bern, Switzerland, 3010
        • Inselspital, Department of Cardiology

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients with severe aortic valve disease referred for transcatheter aortic valve implantation (TAVI) at a single tertiary care center. Patients are enrolled prospectively and undergo evaluation of gut microbiota composition and metabolomic profiles before and after TAVI.

Description

Inclusion Criteria:

  • • 18 years or older

    • Hospitalized for TAVI or investigations before TAVI for significant aortic valve disease

      • Severe CAS is defined as: high flow gradient with normal CO (mean gradient ≥40mmHg, Vmax≥4m/s, valve area ≤ 1cm² or ≤0,6cm/m²) or low flow low gradient (mean gradient<40mmHg, Vmax <4m/s, valve area ≤ 1cm² or ≤0,6cm/m², stroke volume < 35ml/m², LVEF<40%) confirmed by low dose dobutamine echo or high calcium score (> 1200 in women and > 2000 in men), paradoxical low-gradient CAS: LVEF > 55%, Vmax< 4m/s, mean gradient < 40mmHg, area < 1cm²)
      • Combined aortic stenosis and aortic regurgitation, considered as severe valvular heart disease with a need for TAVI.
    • Written informed consent

Exclusion Criteria:

  • - Treatment interfering with the composition of the intestinal microbiota: local or systemic corticosteroids within the last 3 months, antibiotics within the last 3 months, antiretrovirals, bile acid chelators (questran and colesevelam), HIV-targeted antiretroviral therapies, selective serotonin reuptake inhibitor-type antidepressants
  • Clinical criteria: history of cholecystectomy, documented chronic liver disease in the patient, failure to fast on the day of the blood test, inflammatory bowel disease
  • Valve in valve TAVI.
  • LVEF < 20%
  • Patients requiring emergency intervention (myocardial infarction, acute aortic or mitral regurgitation, cardiogenic shock).
  • AS of rheumatic origin, infective endocarditis.

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
Patients with aortic stenosis undergoing TAVI
Patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) as part of routine clinical care. Assessments of gut microbiota composition and metabolomic profiles are performed before the procedure and at 3-month follow-up.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in gut microbiota-derived metabolite levels before and after TAVI
Time Frame: Baseline (pre-TAVI) and 3 months post-TAVI
Quantitative assessment of key gut microbiota-derived metabolites-including bile acids (cholic, chenodeoxycholic, deoxycholic, and lithocholic acid measured via LC-MS in µmol/L), trimethylamine N-oxide (TMAO measured via LC-MS in µmol/L), tryptophan metabolites (measured via LC-MS in µmol/L), and short-chain fatty acids (SCFAs measured via GC-MS in µmol/g) in blood and stool samples, measured before and after transcatheter aortic valve implantation (TAVI).
Baseline (pre-TAVI) and 3 months post-TAVI

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in gut microbiota diversity after TAVI
Time Frame: Baseline and 3 months post-TAVI
Assessment of gut microbiota diversity using 16S rRNA sequencing, including alpha diversity (measured by Shannon and Simpson indices on a scale of 0-10) and beta diversity (measured by Bray-Curtis dissimilarity index score from 0-1), in stool samples collected before and after TAVI.
Baseline and 3 months post-TAVI
Change in gut microbiota taxonomic composition after TAVI
Time Frame: Baseline and 3 months post-TAVI
Analysis of the relative abundance (measured as a percentage of total sequences (%)) and distribution of bacterial families in stool microbiota using 16S rRNA sequencing before and after TAVI.
Baseline and 3 months post-TAVI
Sex-specific differences in gut microbiota changes following TAVI
Time Frame: Baseline and 3 months post-TAVI
Comparison of gut microbiota diversity (Shannon Index score) and composition (relative abundance percentage (%)) between male and female patients before and after TAVI.
Baseline and 3 months post-TAVI
Association between gut microbiota changes and systemic biomarkers
Time Frame: Baseline and 3 months post-TAVI
Evaluation of the statistical correlation (Pearson or Spearman coefficient r) between changes in gut microbiota composition (relative abundance %) and metabolite levels (µmol/L) with systemic markers of inflammation (including IL-6, IL-10, and TNF-α concentration in pg/mL measured via the Meso Scale Discovery [MSD] electrochemiluminescence platform), and cardiovascular function (NT-proBNP in pg/mL).
Baseline and 3 months post-TAVI
Prognostic value of gut microbiota and metabolite changes after TAVI
Time Frame: From baseline to 3 months post-TAVI (and clinical follow-up, if applicable)
Assessment of the statistical correlation (Hazard Ratio or Correlation Coefficient r) between changes in gut microbiota composition (relative abundance %) and metabolite levels (µmol/L) with clinical outcomes, including incidence of heart failure, hemolysis, mortality, and prosthetic valve dysfunction.
From baseline to 3 months post-TAVI (and clinical follow-up, if applicable)

Collaborators and Investigators

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

Sponsor

Insel Gruppe AG, University Hospital Bern

Collaborators

Tours university

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)

March 1, 2024

Primary Completion (Actual)

February 28, 2026

Study Completion (Estimated)

February 28, 2029

Study Registration Dates

First Submitted

April 27, 2026

First Submitted That Met QC Criteria

April 27, 2026

First Posted (Actual)

May 4, 2026

Study Record Updates

Last Update Posted (Actual)

May 8, 2026

Last Update Submitted That Met QC Criteria

May 4, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2023-02339

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

The plan for sharing individual participant data is currently under evaluation. Data sharing will be considered in compliance with institutional guidelines, ethical approvals, and applicable data protection regulations.

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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