An observational study in Calcific Aortic Valve Disease, Inflammation and Dysbiosis, sponsored by Insel Gruppe AG, University Hospital Bern. Active, not recruiting at 1 site in Switzerland. Per ClinicalTrials.gov, last updated 2026-05-08.
Sponsored by Insel Gruppe AG, University Hospital Bern · Observational
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.
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This study's enrollment of 40 is below the median of 95 across 895 observational studies indexed under Inflammation.
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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.
18 years or older
Hospitalized for TAVI or investigations before TAVI for significant aortic valve disease
Exclusion Criteria:
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.
Change in gut microbiota-derived metabolite levels before and after 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).
Time frame: Baseline (pre-TAVI) and 3 months post-TAVI
Change in gut microbiota diversity after 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.
Time frame: Baseline and 3 months post-TAVI
Change in gut microbiota taxonomic composition after 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.
Time frame: Baseline and 3 months post-TAVI
Sex-specific differences in gut microbiota changes following TAVI
Comparison of gut microbiota diversity (Shannon Index score) and composition (relative abundance percentage (%)) between male and female patients before and after TAVI.
Time frame: Baseline and 3 months post-TAVI
Association between gut microbiota changes and systemic biomarkers
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).
Time frame: Baseline and 3 months post-TAVI
Prognostic value of gut microbiota and metabolite changes after TAVI
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.
Time frame: From baseline to 3 months post-TAVI (and clinical follow-up, if applicable)
Plan to share: Undecided — 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.
This study is active, not recruiting, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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Insel Gruppe AG, University Hospital Bern