Calcific aortic stenosis (CAS) is a disease characterized by progressive calcification of the aortic valve, obstructing the passage of blood from the left ventricle into the general circulation. It is the most frequent cause of valve disease in the elderly. To date, no means of preventing the disease has been discovered, and the only treatment available is valve replacement during cardiac surgery, or percutaneous implantation of a valve prosthesis when the narrowing becomes severe and causes symptoms. The intestinal flora or microbiota, the reservoir of all the microorganisms in the gut, is implicated in numerous diseases, particularly of the intestine. But to date, no study has established a link between CAS and microbiota. The intestinal microbiota acts through molecules produced by itself or the host and passing into the bloodstream. In the pathophysiology of CAS, the valve leaflets are breached and do not heal. These molecules can enter and have beneficial or deleterious effects, in particular promoting calcification of aortic valve cells. Concrete objectives: Improve understanding of calcific aortic stenosis in humans Study the composition of intestinal flora in patients with aortic stenosis and compare it with healthy subjects Study the molecules in the intestinal flora likely to be involved in the development of aortic stenosis in humans.
Study Type
OBSERVATIONAL
Enrollment
100
No intervention
Richness of the gut microbiota
The primary endpoint is the evaluation (16S ribosomal ribonucleic acid (rRNA) sequencing) of the species richness using alpha diversity parameters such as the Shannon and Simpson index and diversity between samples using beta diversity with Bray-Curtis dissimilarity approach. The investigators will then identify the bacteria with taxonomy analysis and statistical differences will be done using MaAsLin (Microbiome Multivariable Association with Linear Models) for patients with and without CAS.
Time frame: The sample will be collected at the time of inclusion (with a margin of two additional days depending on the patient's ability to pass stools). The analysis will be performed at the end of the sample collection (an average of 2 years)
Comparison of the levels of the tryptophane metabolites of the gut microbiota in the blood, feces and the aortic valve between patients with and without CAS
The metabolites being studied include tryptophan metabolites (kynurenine pathway, serotonin pathway).
Time frame: The full analysis will be performed at the end of the sample collection. One intermediate analysis is scheduled when half of the samples are collected (one year and two years)
Comparison of the levels of the short chain fatty acids (SCFA) metabolites of the gut microbiota in the blood, feces and the aortic valve between patients with and without CAS
The metabolites being studied include SCFA (acetate, propionate and butyrate).
Time frame: The full analysis will be performed at the end of the sample collection. One intermediate analysis is scheduled when half of the samples are collected (one year and two years)
Comparison of the levels of the trimethylamine N oxide (TMAO) metabolites of the gut microbiota in the blood, feces and the aortic valve between patients with and without CAS
TMAO is derived from trimethylamine (TMA), itself generated by the action of the gut microbiota on dietary choline and phosphatidylcholine contained in red meat, eggs, dairy products and saltwater fish. TMAO and its derivatives (L Carnitine) are measured in blood, stool and valves.
Time frame: The full analysis will be performed at the end of the sample collection. One intermediate analysis is scheduled when half of the samples are collected (one year and two years)
Comparison of the levels of the bile acids metabolites of the gut microbiota in the blood, feces and the aortic valve between patients with and without CAS
The metabolites being studied include 4 bile acids and their derivatives (Cholic, Chenodeoxycholic, Deoxycholic and Lithocholic acid)
Time frame: The full analysis will be performed at the end of the sample collection. One intermediate analysis is scheduled when half of the samples are collected (one year and two years)
Diversity of bacteria families in men and women
Primary endpoint: The primary endpoint is the evaluation (16S rRNA sequencing) of the species richness using alpha diversity parameters such as the Shannon and Simpson index and diversity between samples using beta diversity with Bray-Curtis dissimilarity approach.
Time frame: The sample will be collected at the time of inclusion (with a margin of two additional days depending on the patient's ability to pass stools). The analysis will be performed at the end of the sample collection (an average of 2 years)
Prevalence of bacterial families or species in the microbiota of patients with CAS over the course of time and disease progression.
Primary endpoint: The primary endpoint is the evaluation (16S rRNA sequencing) of the species richness using alpha diversity parameters such as the Shannon and Simpson index and diversity between samples using beta diversity with Bray-Curtis dissimilarity approach.
Time frame: The sample will be collected at the time of inclusion (with a margin of two additional days depending on the patient's ability to pass stools). The analysis will be performed at the end of each year of follow up (an average of 2 years)
Prevalence of bacterial families or species in the microbiota of men versus women with CAS over the course of time and disease progression.
Primary endpoint: The primary endpoint is the evaluation (16S rRNA sequencing) of the species richness using alpha diversity parameters such as the Shannon and Simpson index and diversity between samples using beta diversity with Bray-Curtis dissimilarity approach.
Time frame: The sample will be collected at the time of inclusion (with a margin of two additional days depending on the patient's ability to pass stools). The analysis will be performed at the end of each year of follow up (an average of 2 years)
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