Calcific Aortic Valve Disease, Dysbiosis, Inflammation, TAVI
Conditions
Keywords
Gut microbiota, Metabolomics
Brief summary
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.
Interventions
None listed
Sponsors
Insel Gruppe AG, University Hospital Bern
Tours university
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in gut microbiota-derived metabolite levels before and after TAVI | 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). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in gut microbiota diversity after TAVI | 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. |
| Change in gut microbiota taxonomic composition after TAVI | 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. |
| Sex-specific differences in gut microbiota changes following TAVI | 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. |
| Association between gut microbiota changes and systemic biomarkers | 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). |
| Prognostic value of gut microbiota and metabolite changes after TAVI | 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. |
Countries
Switzerland
Outcome results
None listed