TMAO in Patients With Severe Aortic Stenosis

Inclusion Criteria: * Informed consent to participate in the study * Severe aortic stenosis, defined as aortic valve area \<1.0 cm2 or aortic valve area index \<0.6 cm2/m2 as calculated by the continuity equation on transthoracic echocardiography, regardless of the transvalvular gradient, with or without coexisting symptoms of heart failure * Qualification for surgical aortic valve replacement or transcatheter aortic valve implantation by the Heart Team in accordance with European Society of Cardiology guidelines Exclusion Criteria: * Heart failure of etiology other than aortic stenosis * Coexisting, haemodynamically significant aortic regurgitation * Myocardial infarction within the last 3 months * Coronary revascularization within the last month or planned during transcatheter aortic valve implantation or surgical aortic valve replacement * Chronic kidney disease with estimated glomerular filtration rate \<45 ml/min/1.73 m2 * Acute gastrointestinal disease within the last month * Active neoplastic disease * Chronic inflammatory disease * Autoimmune disease * Chronic intestinal disease * Antibiotic therapy within the last 2 months * Dietary supplements within the last 7 days