The study of new biological heart valves with the "easy change" system, including an assessment of the basic hemodynamic characteristics of the prosthesis, complications associated with valve implantation, and general mortality. Antithrombotic therapy after new biological valve prosthesis is studied. Transesophageal ultrasound is used for assessment of aortic strain, left ventricular strain, and 3D reconstruction of implanted bioprosthesis. The quality of life of patients is assessed using SF36 questionnaire. Heart failure after surgery is assessed by six-minute walking test and plasma BNP level.